Multilayer shell for food products containing coarse-grained particles in intermediate layer and method of its production

FIELD: food industry.

SUBSTANCE: invention relates to a tubular multilayer thermoplastic shell for food products which contains an outer layer (Z), an inner layer (I) and at least one layer (P) located between them which contains coarse-grained nonorganic and/or organic particles and more than 50% (by weight) of at least one thermoplastic polymer. At least one sort of the coarse-grained particles has average diametre of equivalent ball d₅₀ exceeding 5 mcm while the surface of the outer layer (Z) and/or inner layer (I) has average (based on results of 5 measurements) profile irregularity height R_z equal to at least 5 mcm. Furthermore, the invention relates to a method of production of the said shell for food products.

EFFECT: according to the invention idea the shell is basically or completely identical to natural, collagenic, skin and fibrous or fibre-reinforced cellulose shell in terms of appearance and has larger stability and low level of manufacturing defect.

18 cl, 2 tbl, 9 ex

The invention relates to a tubular multilayer thermoplastic shell for food, which contains the outer layer, inner layer and at least one layer located between them. In addition, the invention relates to a method of manufacturing the specified shell.

Wrappers for food products, in particular sausage casing traditionally made from natural intestinal membranes, collagen fibers, skin fibers, cellulose, reinforced fibers, or textiles. In the world market these shells still account for a major share, particularly in the production of high quality sausages. In second place is the shell of thermoplastic polymers, in particular polyamide or polyamide-polyolefin multilayer compositions. Most thermoplastic shells in the manufacture subjected to extrusion in order to improve their ability to heat shrinkage and mechanical properties. However, thermoplastic membranes have a very unnatural appearance. In addition, they are usually so smooth that loosely resemble naturally structured surface collagen intestinal membranes and thus easily slip from your hands when filling.

Collagen and skin-fibrous casings are produced from the skin of cattle on the Yan-intensive and environmentally harmful method: skin tissue is dissolved acids, for example lactic acid, to fibrils; high-viscosity mass ekstragiruyut, and then using gaseous ammonia or ammonium hydroxide slowly and compact coagulated and uprochnyayuschie drying produce crosslinking (curing) to give products a sufficient stability, so that they can withstand the process of scalding without significant loss of strength. However, for various reasons, such as the epidemic of BSE in cattle and abuse of antibiotics, natural casings, as the shell of the fibers of the skin, becoming less acceptable to consumers. In addition, there is the threat of legal restrictions on their use. It is therefore desirable to find an alternative. Cellulose casings, even reinforced by the fibers can solve this problem only to a limited extent. The method of their production is not less labour-intensive and environmentally harmful than a method of manufacturing a collagen membranes and skin-fibrous membranes. Inedible collagen membrane called the skin-fibrous membranes.

The big advantage of thermoplastic shells for food is the simplicity and economy of manufacture. However, the end user has a lot of prejudice against the sausages in such shells. Natural is th high gloss polymer surface often gives the impression of low quality product. Appearance still could be improved only at the expense of matting surface, but not to such an extent to ensure that the imitation of the natural collagen membranes, skin-fibrous membranes or cellulose casing, reinforced with fibers. In addition, the products have a low surface roughness, if the polymer surface is moistened by the liquid or fat.

In natural intestinal membranes, especially in the membranes of cellulose, reinforced fiber, as well as in the membranes of collagen fibrous texture provides a coarse structured rough surface. The consumer, who is used to such appearance for many decades, associating it with a high quality and, accordingly, with the traditional technology of production of sausage products.

From DE-A 4141292 known single-layer transparent, oriented along two axes of the tubular sheath for food on polyamide basis, which contain finely dispersed pigments with a particle size of from 0.01 to 15 μm. This finely dispersed pigments should have a low tendency to connection blocks.

In WO 02/00026 described multilayer, oriented along two axes of the tubular polymeric membranes, which consist of at least one layer made of polyamide and, if necessary, polyolefin, with dispergirovany the bag into him nanoparticles with a content of from 0.1 to 4% by weight. The nanoparticles consist, in particular, of the layered silicates, stretching them in any direction does not exceed 100 nm. Described the film has high transparency and provides a significant increase in the oxygen barrier.

In WO 01/03508 described cellulose casing for food products, on the outer side of which is coated from an aqueous suspension based on cationic resin and silicon oxide. The particle size of the inorganic substances are, as a rule, in the range from 0.1 to 25 μm, and its content can vary from 20 to 83,3% by mass.

In WO 03/020513 described highly permeable composite film, which consist at least of two layers: the inner layer, which in turn consists, generally, of the polyolefin and the inorganic filler, and from the outer layer, which contains a mixture of at least two incompatible polymers, preferably of atactic polypropylene and low density polyethylene or polystyrene and clutch. Due to the orientation of this multi-layered composition of micro-cracks occur, which provide a high permeability film. The use of such materials lies primarily in the field of hygienic products, such as baby diapers.

In these publications the natural appearance and the structure surface is, i.e. haptic and visual simulation of a collagen film, are not the primary task. Entered inorganic substances are there primarily to increase the roughness, which is required in the filling process is performed, in particular, manually, to reduce the tendency to block when the sliding pieces per roll, for improving the oxygen barrier or permeability, and in the case of the organic filler is to improve Biodegradability. While small particles do not provide sufficient roughness. In addition, these publications apply a polymeric matrix and a combination of polymeric materials, which are partially different from the materials used according to the present invention.

In DE-A 10345839 described multi-layer casing for food products, in the outer layer where organic matter dispersed in the polymeric matrix. This dispersed substance may be introduced into the mass of the outer layer in the form of particles or in any other form. However, it is indicated that the content of coarse-grained soft organic particles in the mass of the outer layer causes difficulties in processing, in particular, leads to the formation of residue on the instruments, and in particular on the edge of the nozzle mass of the co-extrusion nozzle. In addition, organic components, about daysie small heat resistance at high temperature extrusion, which often lie in the range from 200 to 280°C, can be thermally destroyed, to thermally decompose and/or burn. It is preferable to add to the mass of organic matter, which holds a substantial or absolute temperature in the temperature of the extrusion process. Such components are often also form deposits on the tool. These deposits, as in the case of inorganic particles, lead to the need for frequent stops process for cleaning the injectors every few minutes, to the curvature of the shell segments, which are often quite long, and the deviations of the value of the effective diameter (caliber) during extrusion, and therefore, the deviations of the diameter of the extrusion shell.

In DE-A 102004005642 described multilayer membranes for food, in the outer layer containing coarse inorganic particles, which give the shell greater dullness and roughness. It is stated that the presence of the mass of the outer layer of coarse-grained solid inorganic particles leads to technological difficulties.

In particular, this leads to the appearance of deposits on the injectors, causing the need for frequent cleaning if necessary every 5-10 minutes, when it is necessary to interrupt the production process, as well as to the otkloneniyam caliber and, therefore, the deviations of the diameter of the shell. In the case of particularly large inorganic particles of the shell may be because they are more fragile, crack on these particles and even to break or be broken.

Particles of solid material cause abrasion of metal parts of the extruder nozzle, especially their edges, as well as rapid wear of such tools as knives, which are used, for example, for cutting wrappers for food products into segments of the desired length. They quickly blunted due to the presence of solid particles on the surface of the shell and must be replaced or additional sharpening.

You can also refer to unpublished patent application DE 10345839.5 and DE 102004005642.0 that belong to the same shells for food, relative to the applied substances, particles and their sizes, manufacturing methods and properties of the fabricated membranes.

In connection with the foregoing the present invention is a multilayer membrane for food, appearance, and/or roughness which largely or completely matches the natural, collagen, skin-fibrous or cellulose membrane, reinforced fibers, and which provides better process stability and low levels of marriage.

This is the problem solved at the expense of the tubular multilayer thermoplastic shells for food, which contains the outer layer (Z), inner layer (I) and at least one located between the layer (P) and differs in that at least one layer (B) contains more than 50% by weight of at least one thermoplastic polymer and coarse inorganic and/or organic particles, at least one kind of coarse particles has an average equivalent diameter of the ball d₅₀more than 5 μm, and the surface of the outer layer (Z) and/or the inner layer (I) has an average height R_zroughness profile of at least 5 μm by averaging the results of 5 measurements.

Preferred for the layer (B) are thermoplastic polymers based on at least one of the following (co)polymers: (co-)polyamide, (co)polyester, (co)polyolefin, (co-)polyurethane containing polyvinyl (co-)polymer, co-copolymers and/or mixtures thereof.

Different types of particles differ significantly from each other. For example, the first type of particles may be different from the second different chemical composition significantly different methods of manufacture, substantially different forms of particles and/or significantly different distribution of particle sizes.

The layer containing coarse particles, denoted hereinafter as the layer (B). It borders directly with lying on the outside on top of the spine of the outer layer (Z) and/or other intermediate layers. It can border with inner layer (I), which forms the inner surface of the shell. One or more layers (B) contain at least one inorganic and/or organic solid substance in the form of coarse particles. Some of these coarse particles may have a diameter that exceeds the average thickness of the whole layered structure of the shell. Due to this, at least part of the coarse particles can exert pressure on the border with their surface layers (Z) and/or (I) and/or may cause a curvature of at least one layer that can give the shell greater roughness. Coarse particles of at least one layer (B) preferably have such distribution and abundance, so that on average at least three particles 1 mm²the outer or the inner surface had a diameter and location in the shell, providing rise for at least part of the flat surface areas due to the expansion of the main mass around these particles and/or availability of items particles protruding from the main mass. Coarse particle mass, preferably built after the extrusion, mainly in a thin layer, and the layered structure forms a swelling around the coarse particles.

When this outer layer (Z) and inner layer (I) predpochtitel what about the not contain such coarse particles. However, these layers and/or at least one of the intermediate layers may contain a separate Mat of inorganic and/or organic fillers with particle sizes, which are often in the range of 0.5 to 8 μm, preferably in the range from 1 to 6 μm, and particularly preferably in the range from 1.5 to 5 μm. These matting particles often have dimensions not exceeding the thickness of the outer layer (Z). The size distribution of this matting means is preferably relatively narrow, so that at least one matting agent does not contain or contains almost no particles greater than 8 μm, greater than 10 microns, greater than 13 microns, greater than 16 microns, or greater than 20 μm. Due to this, the shell can be given the appearance and tactile characteristics similar to a dull matte collagen membrane, as well as to provide the optimum surface roughness. At least one layer, in particular the outer layer (Z) or the inner layer (I)comprises at least one matting agent.

Casing for food products according to the invention can contain, in particular, 3, 4, 5, 6, 7, 8, 9 or 10 consecutive layers. So this shell implementations may consist of an outer layer (Z), inner layer (I), as well as one, two, three, four, five, six, seven or eight so n is called the intermediate layers, of which at least one intermediate layer made of a mixture of coarse-grained inorganic and/or organic particles, these particles during the manufacturing process layer from this mass by way of coextrusion of at least partially retain their shape or do not change significantly, or no change. This applies at least one layer (B). In preferred embodiments of the invention, the shell except for the outer layer (Z) and inner layer (I) contains one, two, three, or four additional layers, which represent the functional layers of type (A), (B), (C) and/or (HV). Different layers can - though not necessarily strictly separated from each other. Between two adjacent layers can be smooth transitions and/or uneven, dramatically changing the surface boundary. Layer (B) preferably has a thickness of at least 5 μm, at least 10 μm, at least 12.5 μm, or at least 15 μm, particularly preferably at least 17.5 microns in size, at least 20 microns, or at least 22.5 microns, most preferably at least 25 microns.

The total thickness of the shell is usually in the range from 20 to 300 μm, often in the range from 25 to 240 μm, preferably in the range from 30 to 180 μm, particularly preferably more than 35 or less than 140 μm or what the Eney 120 μm, most preferably more than 35 or less than 100 μm, or less than 80 μm. Often shell according to the invention have a total thickness of about 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76 and/or 78 microns.

Shell food is, in particular, almost cylindrical, preferably has an almost circular cross-section and is flexible. It can be used as sausage casings, as well as membranes for dairy and/or other food products. Such a wrapper for food products can be applied in the form of pieces, corrugated tubes from natural intestinal membranes, for example from the rectum, and/or in the form of a ring.

The shell according to the present invention differs from the known prototypes first appearance, which is similar to the shells of the collagen fibers of the skin, pulp reinforced with fibers and/or natural intestinal membranes, multilayer structure having a high content of synthetic thermoplastic polymer and containing at least one layer (P)located between the outer layer (Z) and inner layer (I), as well as higher stability of the manufacturing process.

Under thermoplastic substances in this description refers to such substances, which largely consist of typical thermoplastic floor is Mer. Many of these typical thermoplastic polymers higher than the temperature of operation and the area below the melt have a transitional region of fluidity and/or melting point, particularly at least partially for crystalline polymers.

In many embodiments of the invention at least one layer (B)comprising coarse particles contain inorganic and/or organic particles with equivalent diameter of the ball more than 15 μm or more to 20 μm, preferably more than 25 μm, 30 μm, 35 μm or more to 40 μm, particularly preferably 45 μm or more to 50 μm, even more preferably more than 55 μm, 60 μm or more, and most preferably more than 65 μm or more and 70 μm. However, in some embodiments of the invention may occur inorganic and/or organic particles, in particular, the organic particles with equivalent diameter of the ball more than 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or more than 100 μm. The size distribution of coarse particles is preferably broad or very broad to include some particularly large particles. Preferably all inorganic and/or organic particles of at least one layer (B) or at least their isometrically molded particles have a distribution is iameter equivalent of a ball at least partially within 20 to 40 microns. At least one layer (B) contains at least 0.5% by weight of inorganic and/or organic particles, preferably at least 0.8, or 1.2% by weight, and most preferably at least 1.6 or 2% by mass.

As inorganic substances that can be added to the layer (R) shell, suitable are, in particular:

1. fiber glass, for example glass fibers, glass filaments and/or glass staple fiber;

2. short mineral fibers, e.g. basalt wool, slag wool and/or mineral wool;

3. fillers or reinforcing materials of carbonates, such as chalk, limestone powder, calcite, precipitated calcium carbonate, magnesium carbonate, barium carbonate, dolomite and/or other mixed carbonates;

4. sulfates, such as barium sulfate and/or calcium sulfate;

5. silicates, such as talc, pyrophyllite, chlorite, horn blende, mica, kaolin, clay, wollastonite, rock flour, such as slate flour, synthesized or natural alkaline or alkaline-earth silicates, silicates with several cations, for example MgFe-, AIMg-, CaAl-, NaAl - or SA1-silicates, feldspars, feldspathic, mullite, zeolites and/or alkaline earth metasilicate;

6. silicic acid of various types, such as quartz, fused quartz, cristobalite, land and/or grinding material is with a very high content of SiO ₂as, for example, diatomaceous earth and/or Nabulsi silica, precipitated or pyrogenic silica, glass powder, pumice powder, perlite, it is the Frit and/or glass (micro)beads, and/or silica-alumina beads in the form of solid beads, hollow spheres and/or their fragments;

7. oxides, such as aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, titanium oxide, silicon dioxide and/or;

8. other materials such as carbon fiber, particles of carbon black and/or graphite.

Mainly or largely inorganic particles include particles on the basis of aluminum oxide, carbonate, phosphate, silica, silicate such as wollastonite, sulfate, rocks and/or glassy substance.

The surface features of the inorganic particles can be modified, for example, a clutch, to ensure better compatibility with the surrounding polymer matrix (host mass matrix) or to have a colored coating. In a polymer matrix with inorganic and/or organic particles can occur cavity is formed, in particular, when the hood.

Major inorganic and/or organic particles in layer (B) is particularly necessary to make the shell of relief and roughness. A certain fraction of the medium and/or small Neorganicheskie and/or organic particles may serve to enhance opacity and receive a specific microstructure. You can use a mixture of particles of different shapes. However, the proportion of relatively large particles having mainly two-dimensional configuration, such as plates, preferably should be low or practically zero.

In some embodiments of at least part of the inorganic particles is preferably isometric, linear, needle-like and/or fibrous form. In some cases, it is preferable that most of the applied particles, especially large particles had such a form. It is preferable to use a mixture of inorganic particles, which contains almost isometric particles and mostly linear, needle-like and/or fibrous particles, in particular in respect of from 5:95 to 95:5, preferably in the ratio of from 15:85 to 85:15, more preferably for more than 25:75, or more than 35:65, or less than 75:25, or less than 65:35, and most preferably in the ratio of about 45:55, or 55:45. These particles may have a more or less orderly arrangement. However, preferably they may have an irregular arrangement in the layer (B) in the absence of a preferential direction. The larger particles having average or high hardness, the preferred curvature of the largest particles.

Particles in layer (B), first of all, having the form in the fibre, and/or substantially isometric, needle and/or lamellar particles give the shell a very natural matte sheen and good tactile characteristics. The surface becomes light roughness, which can be adjusted by adjusting the type, quantity and distribution of particle size. The content of the particles may also have an impact on the ability of the shell to maintain a round cross-section. In addition, it was found that inorganic particles can act as a reinforcing element, greatly increasing the stability of the caliber (diameter variation of material with filler compared to the material without filler.

The mass ratio of the inorganic and/or organic particles to the mass of polymer in the entire wrapper for food products is preferably from 0.01:99,99 to 40:60, more preferably at least 0.05:99,95 to 30:70, more preferably at least 0.1:to 99.9 to 20:80, especially at least 0.3:99,7 or at least from 0.5:99,5 to 16:84, 12:88 8:92, preferably at least 0.8:99,2, or at least from 1:99 to 6:94, or even up to 4:96.

The mass ratio of the inorganic and/or organic particles to the mass of polymer in the layer (P) and/or in a different layer containing large particles for one layer is preferably from 0.1:to 99.9 to 50:5, more preferably at least 0.3:99,7 to 40:60, more preferably at least 0.5:of 99.5 to 30:70, especially at least from 0.75:99,25 or at least from 1:99 to 25:75, or up to 20:80, preferably at least 1.5:98,5 or at least from 2:98 to 15:85, or even up to 10:90.

Along with inorganic particles or instead of the layer (B) may contain at least one kind of organic particles.

The organic particles are preferably polysaccharides, proteins, heat-resistant polymers which are used, in particular, for the manufacture of materials, at least chemically similar to the materials used for artificial fibers, and mixtures thereof. They preferably consist primarily or substantially of particles on the basis of polysaccharides, proteins and/or heat-resistant polymers. They are preferably chosen from a sufficiently heat-resistant organic material: organic material with a high melting point of organic materials with higher melting point and/or from organic materials with high decomposition temperature, especially the temperature of melting and/or decomposition temperature of more than 140°C, more than 160°C, 180°C, 200°C, more than 220°C, more than 240°C, 260°C and/or more than 280°C and/or temperature RASMAG the help of more than 180°C, more than 200°C, more than 220°C and/or more than 240°C. the Temperature for the selected method of manufacture or selected organic substances is manifested in what part of the organic matter gets burnt, burned or decomposes otherwise under the influence of temperature. These degradation processes are often recognized by light or dark brown color. While, for example, alginates and carrageenan quite sensitive to temperature, guar gum somewhat less sensitive to temperature, starch powder, usually less sensitive to temperature, and cellulose is the most heat-resistant of these substances. So many types of organic particles, which can be added to a mass of at least one layer, for reasons of thermal stability, it is recommended to select particles of cellulose and/or starch. Especially preferred are the masses or layers containing at least one synthetic material for the matrix based on polyamide and/or containing at least one polyamide particles based on at least one polysaccharide, these materials have a higher proportion of polar bonds.

Layer (B), the modified inorganic and/or organic particles according to the invention, due to the large size of these particles or large agglomerates and/or aggregates the ri producing film membranes leads to the formation of rough matte surface of the outer layer (Z) and/or the inner layer (I), what can bring them by their appearance and tactile characteristics to the surface, for example, cellulose and fibrous casings or collagen casings. This impression will be strengthened if you enter into the outer layer (Z) and/or the inner layer (I) matting agent, such as inorganic and/or organic particles with an average particle size in the layer or in a form of particles from 0.5 to 8 μm. When this layer is P or any other layer may also contain a mixture of at least one polysaccharide, one protein and/or one stable at high temperature synthetic material, in particular in the form of fibers and/or mainly isometric and/or needle-shaped particles, particularly preferably of more or less isometric asymmetrical rounded and/or polyhedral particles.

At least one polysaccharide can be entered in at least one layer in the form of added particles and/or in the matrix. This used at least one polysaccharide may be of natural origin or may be chemically synthesized. It may have branched reticular or linear structure. Suitable polysaccharides are natural thermoplastic starches (thermoplastische blitz chess, TPS) and/or starch. Among unmodified starches preferred natural and/who do termoplastichnye maize and/or potato starch. Starch represents, for example, esters of starch, in particular starch acetate, maleinate starch, starch propionate, starch butyrate, starch laurate and/or oleate starch xanthate starch, phosphate starch sulfate, starch nitrate, starch, ethers, starch, in particular a simple methyl ether starch, simple ethyl ether of starch, simple propyl ether of starch, simple butyl ether starch, simple alkenilovyh ether starch, simple oxicology ether of starch and/or simple oxypropylene ether starch, grafted starches, such as starch, grafted with maleic anhydride and/or succinic acid, and/or oxidized starches, for example dialdehyde starch, carboxyl starch and/or starch is decomposed by persulfate.

Alternative or in combination with at least one of the above starches or starch may contain other components from a family of polysaccharides. These include, in particular, vegetable powders, fibers and fiber segments, for example, from cellulose, cotton, Kapka, flax, hemp, jute, kenaf, baerii, sisal, peat, straw, wheat, potato, tomato, carrot, coconut, pineapple, apples, oranges, spruce, pine and/or tube. Hereinafter fiber, as well as their long or short segments collectively referred to as fiber is AMI.

In addition, you can use organic, synthetic, in particular having high heat resistance and/or high melting point synthetic fibers or polymer powders in the form of added particles and/or in the matrix, for example, on the basis of polyethylene, polypropylene, polyamide, polyacrylonitrile, complex, polyester, fluoropolymer, polysulfone, polyethersulfone, polyetherketone, polyster, polyaramid, polyimide, complex, aromatic polyester, polynoxylin, polyanaline, polybenzimidazole and/or polymer ladder.

Such fibers and/or powders (called particles together), generally have a much higher melting point, a much higher softening temperature and/or a much higher decomposition temperature than the polymer matrix surrounding them in the shell for food, so when processing they are not melted or melted only partially, and/or softened, or melted with a higher viscosity than the surrounding polymer matrix, and can remain visible in the film in the form of so-called inclusions. Therefore, these organic components are also very effective for obtaining a rough structured surface.

In addition, at least one layer over erati at least one additional high and/or low molecular weight component, for example, at least one plasticizer, in particular glycerol, glycol, ester of glycerol and a carboxylic acid, an ester of phthalic acid, stabilizer, bactericidal component, mildew-resistant component and/or at least one of any other special Supplement.

As the polymer component, preferably used in at least one layer of the shell, particularly preferably in the layer (P), in particular, for the mass matrix or layer, fundamentally fit all thermoplastic polymers, such as polyurethanes, urethane polymers, ethers, urethane polymers, esters and ethers, polystyrenes, aliphatic (co-)polyamides, polyolefins, such as polyethylene and/or polypropylene, copolymers of ethylene, propylene and/or α-olefins, aliphatic and/or partially aromatic copolymers of polystyrene, copolymers of vinyl, for example ethylenevinylacetate copolymers, polyvinyl alcohols and their copolymers and/or mixtures thereof. Among the polyurethanes are preferred preaddukta, for example, obtained by reaction of diisocyanate (Toluylendiisocyanat, TDI), isophorondiisocyanate and/or hexamethylenediisocyanate with poly-1,2-propane diol (Polypropylenglykol, PPG) and/or poly-1,4-butanediol (Polytetramethylenglykol, PTMG). Among the polyamides are particularly suitable RA, RA, RA, RA/66 and/or RA/12. Among with whom you particularly preferred polyesters are polyactide, polycaprolactone, copolymers of aliphatic diols with aliphatic dicarboxylic acids and terephthalic acids, and poly(butylenglycoladiapinate). Often the composition of at least one layer, in particular a layer (B)contains a mixture of one or at least two of the above thermoplastic polymers.

The content of thermoplastic components in at least one layer, in particular in the bearing layer, there may be more than 50% by weight, preferably more than 55 or 60% by weight, particularly preferably more than 65 or 70% by weight, or even more than 75, 80 or 85% by weight, in particular, on the basis of at least one (co)polyamide and possibly at least one of the other polymers and/or copolymers.

In addition, at least one layer may contain at least one additional organic matter, for example, on the basis of carbohydrates, particularly starch and/or protein, and/or additives, such as high and/or low-molecular components, in particular plasticizers, such as glycerin, polyethylene glycol, esters of glycerol and carboxylic acids, esters of phthalic acid, or stabilizers, bactericidal and/or fungicidal substances. Organic particles preferably plastificator at least partially at least one plasticizer and thereby make for men is our least partially thermoplastic, to organic particles at least partially formed of a mixed phase of at least one substance, the bulk, and that this was accompanied by a softening of their surface and/or at least partial dissolution.

Colouring and variations of colourings coextruded wrappers for food products can be adjusted by adding inorganic and/or organic dyes and/or inorganic and/or organic pigments, which in the context of this application relate to the particles in one or more of any of the layers, particularly the layer (P), and change due to their different numbers and different homogeneity or structure.

All or nearly all of the layers of wrappers for food products are preferably uniform or have a homogenous structure, or almost homogeneous, if not to take into account the distribution of inorganic and/or organic particles and/or distribution of inorganic and/or organic dyes and/or color differences. Inside the matrix can often be more or less uniform distribution are not mixed with each other organic substances and/or particles. If organic substances forming the matrix and the organic particles have different chemical properties and therefore incompatible, often they are not mixed and is not completely mixed and form a multiphase mixture, which in turn produces some kind of granular structure, consisting of at least two phases. However, if the chemical properties of all or some organic substances are fairly or very similar, they can form a General mixed phase. When this organic particles, such as plasticized and thus became a thermoplastic starch particles, in contact with some of the other thermoplastic organic substances can even be partially or completely dissolve and form a mixed phase.

Layer containing at least two inorganic and/or organic phase, in which the individual substances of the matrix and contained particles are not formed of at least one mixed phase in the manufacturing process, and represent a separate phase, may have a different refractive indices, if the resulting structure is fine-grained and different phases, including the contained particles have different optical properties. In this case, the layer due to the different optical properties may create the impression Mat, which is caused not by the presence of surface roughness and pore volume, however, may increase thanks to them. The more optically effective boundary surface and the greater the difference in optical properties, in which lastnosti refractive indices, the stronger the impression Mat.

At least one layer (B) preferably contains at least 0.05% by volume or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 10 μm and/or volume of particles of at least 524 μm³or at least 15 μm and/or displacement of particles at least 1767 μm³especially preferably at least 0.05% by volume or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 20 μm or displacement of particles at least 4189 μm³or at least 0.05% by volume, or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 25 microns or displacement of particles at least 8181 μm³or at least 0.05% by volume, or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 30 μm or displacement of particles at least 14137 μm³most preferably at least 0.05% by volume or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 40 μm or displacement of particles at least 33510 μm³or less is th least 0.05% by volume, or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 45 μm or displacement of particles at least 47713 μm³in particular at least 0.05% by volume or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 50 μm or displacement of particles at least 65450 μm³or at least 0.05% by volume, or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 55 μm or displacement of particles at least 87114 μm³first of all - at least 0.05% by volume or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 60 μm or displacement of particles at least 113097 μm³or at least 0.05% by volume, or at least 0.2% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 70 μm or displacement of particles at least 179594 μm³.

In the shell according to the invention the combination of inorganic and/or organic particles of at least one layer (B) or at least largely isometrically formed particles have an equivalent diameter of the ball predpochtite the flax at least in the range from 25 to 70 microns, from 30 to 80 microns, or from 40 to 90 μm, most preferably in the range from 50 to 100 μm, from 60 to 110 μm, or from 70 to 120 μm. Along with particles in the selected listed here within may be more than fine particles.

In some embodiments of the combination of inorganic and/or organic particles of at least one layer (B) comprises preferably at least 10% by volume isometrically molded particles relative to the amount of all inorganic and/or organic particles, more preferably at least 30% by volume, even more preferably at least 50% by volume, and most preferably at least 70% by volume.

In some embodiments of the combination of inorganic and/or organic particles of at least one layer (B) contains fibrous, needle-like or linear particle, if the particle shape is represented to a certain extent, in the amount of preferably at least 2% by volume of the total volume of the particles, more preferably at least 5% by volume, even more preferably at least 10% by volume, and most preferably at least 20% by volume.

At least one layer (B) preferably contains at least 0.5% by weight of particles selected from inorganic and/or organic particles, more p is edocfile - at least 1, 2 or 4% by weight, particularly preferably at least 8, 10, 13, or 18% by weight, even more preferably at least 20, 24, or 28% by weight, and most preferably at least 32, or at least 36% by mass.

However, if the composition of the outer layer (Z) and/or any other layer type fibers, in some embodiments of the fibrous content of inorganic particles is preferably at least 0.1% by weight, particularly preferably at least 0.5% by weight, more preferably at least 1, 2 or 4% by weight, even more preferably at least 6, 10 or 15% by weight, and most preferably at least 20 mass%.

In order to achieve the tactile characteristics of natural, collagen, skin-fibrous or cellulose casing, reinforced with fibers, it is preferable to provide the following values of the surface roughness of the outer layer averaged at least according to the results of 5 measurements:

R_a≥0.8 μm, particularly preferably R_a≥1,0 μm, more preferably R_a≥1.2 microns, even more preferably R_a≥1.4 µm, and most preferably R_a≥1.6 ám and/or

R_z≥5.0 µm, particularly preferably R_z≥to 6.0 μm, more preferably R_z≥7.0 µm, even more pre is respectfully - R_z≥8.0 µm, and most preferably R_z≥to 9.0 μm and/or

R_max≥to 6.0 μm, particularly preferably R_max≥7.5 μm, more preferably R_max≥9 μm, even more preferably R_max≥to 10.5 μm, and most preferably R_max≥12 μm.

In particular, the average roughness values lie within approximately R_a≥1,8 µm, R_a≤5.0 µm, R_z≥10 ám, R_z≤35 μm, R_max≥13 μm and/or R_max≥45 μm. Average roughness preferably comprise: R_aabout 2, 2,2, 2,4, 2,6, 2,8, 3,0, 3,2, 3,4, 3,6, 3,8, 4, 4,2, 4,4, 4,6 4.8 μm, R_zabout 11, 12, 13, 14, 15, 16, 17, 19, 21, 23, 25, 27, 29, 31 or 33 μm and/or Rmax of about 14, 15, 16, 17, 18, 19, 20, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41 or 43 mm.

In order to achieve an appearance similar to natural collagen, skin-fibrous or cellulosic membranes, reinforced fibers, it is preferable to provide the following values of the surface gloss of the outer layer averaged at least according to the results of 5 measurements at an angle of incidence of the beam 60°:

in particular, the value of the surface gloss of the outer layer defined by using the Micro-Gloss 60 manufactured by BYK Gardner averaged at least according to the results of 5 measurements is not more than 65. The averaged values of the index glitter preference shall be sustained fashion ≤65, particularly preferably ≤55, more preferably ≤45, even more preferably ≤35, and most preferably ≤25. The smaller values of the index glitter, the more matte looks the outer layer (Z) and/or the inner layer (I), and the reasons for this may be, although not necessarily, associated with components or not only with the components of these layers. The averaged values of the index glitter make up≥0,5, ≥2, ≥4, ≥6 or ≥8, respectively≤22, ≤20, ≤18, ≤16 or ≤14. Preferably they are about 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 or 21.

Measured on dry samples, the tensile strength of the membranes according to the invention is preferably at least 20, 30 or 40 N/mm²especially preferably at least 50 or 60 N/mm²more preferably at least 70 or 80 N/mm²and most preferably 90 or 100 N/mm².

Measured on dry samples, the elongation at rupture of the membranes according to the invention is preferably at least 30, 40, 50, or 60%, especially preferably at least 70 or 80%, more preferably at least 90, or 100%, and most preferably -110 or 120%.

At least one layer except the outer layer (Z), or at the same time provides typical for polymers mechanical properties of membranes, such as high strength at which ADrive and/or high elasticity. This at least one layer is of great importance as a carrier layer. At least one supporting layer should be made, whenever possible, whole and should contain, if possible, a small number of particles or not include them at all, or contain only small particles, because they tend to be somewhat degrade the mechanical properties of the shell. Therefore, the layer (B) only in rare cases can be a supporting layer. Supporting layer preferably has a thickness of at least 15 μm, particularly preferably of at least 18 μm, most preferably at least 22 microns. At least one layer except the outer layer (Z), provides gas and vapour resistance. In some embodiments of the outer layer (Z) can also exhibit a high gas and water vapour barrier.

At least one more layer than the layer (B) preferably contains at least one polymer-based (co-)polyamide, polyolefin, copolymer of ethylene and vinyl alcohol (Ethylen-Vinilakohol-Copolymer, EVOH), vinylanthracene (co-)polymer and/or copolymerizate properties clutch. Particularly preferably at least one of the layers of the membrane contains a polymer-based (co-)polyamide in an amount of at least 50% by weight relative to the weight of the layer or at measures is 55% by weight, or at least 60% by weight, particularly preferably at least 65 mass% or at least 70% by weight, or at least 75% by weight, more preferably at least 80 mass% or at least 85% by weight, or at least 90% by weight, and most preferably at least 95 mass% or at least 98% by weight, or even about 100% by weight. This layer may also be the outer layer (Z) and to be enriched (co-)polyamide. However, it is often preferred to other layer other than the outer layer (Z) and/or at least one layer (B)had the function and composition of the layer (A). In many embodiments of the layers (B) are not a carrier layers due to the fact that they contain relatively large inorganic and/or organic particles and do not possess the appropriate properties or sufficient thickness.

Enriched (co-)polyamide layers (hereinafter abbreviated as denoted by "A") may contain one or more aliphatic polyamides and/or aliphatic copolyamids, and partially aromatic polyamides and/or partially aromatic copolyamids. Their examples are:

- aliphatic polyamides: RA, RA, RA;

- aliphatic copolyamids: R/6, R/66, R/69, R/9, R/10, R/12, complicated polyamidoamine, simple polyamidoamine, copolymer of simple and complex floor is amidoamines, polyamidoamine, the block copolymer simple polyamidoamine;

partially aromatic polyamides: PA6-I, nylon-MXD6 (polycondensate of meta-xylylenediamine and adipic acid), or

partially aromatic copolyamids: PA-I/6-T, PA-6/6-I.

Particularly preferred components are R, RA, RA, RA/66, nylon-MXD6, and PA-I/6-t Especially preferred mixtures contain at least two of these polyamides. The content of the partially aromatic (co)polyamides is not more than 40% by weight relative to the weight of the layer (A), particularly preferably not more than 25 mass%.

Layer (A) may optionally contain other polymers such as a copolymer of ethylene and methacrylic acid (EMAA), derivatives, ionomers, or EVON-soluble (hot) water synthetic polymers, such as vinyl alcohol, partially or completely saponified, copolymers of vinyl alcohol with propene-1-I, polyalkylene glycols, polyvinylpyrrolidone, copolymers of vinylpyrrolidone with at least one α,β-olefinic unsaturated Monomeric structural unit, polymerizati N-vinylamides or (co-)polymers of acrylic acid and/or acrylamide. The content of other polymers preferably does not exceed 35% by weight relative to the weight of the layer (A). In addition, if required, the layers (A) can also contain pigments and/or other tibicines polymer additives.

In many cases, it is preferable that at least one layer served as a barrier to water vapor. Such a layer may be at least one polyolefin layer. Polyolefin layers (hereinafter referred to as layers "In") typically consist of polyethylene, polypropylene and/or copolymers with elements of ethylene, propylene and/or α-olefins, preferably 4-8 carbon atoms, and/or dienes. You can also use functionalized vinyl monomers, for example vinyl acetate, (meth-)acrylic acid esters, (meth-)acrylic acid, as structural units of the copolymers. Particularly suitable are copolymers With₂/S₃and/or C₂/C₈. Layers (C) first and foremost function of moisture as polyolefins typically have a very low permeability for water vapor. In addition, the layers (B) may optionally contain dyes and/or fine-grained pigments which are usually used for painting or for protection from UV radiation. These layers can also be painted.

To ensure a high barrier to oxygen and other gases, if necessary, you can use additional layers (hereinafter referred to as layers) with the corresponding blocking action. Suitable polymers are copolymers of ethyl and delovogo alcohol, partially or completely saponified (EVOH), and vinylidenechloride copolymers, such as vinyl chloride or methyl acrylate as the co monomer grades, Polyvinylidenchlorid, PVDC). These polymers may also contain additives, for example plasticizers, other polymers, such as copolyamids or ionomers. Layers (b) and (C) are usually thermoplastic nature.

Note that the layers (A), (b) and (C) in the multilayer film is not always well seize each other independently. To get a good grasp as an intermediate layer and/or the inner layer using at least one additional adhesive layer ("HV"), which in the manufacture of films, for example, by way of coextrusion provides adhesion with adjacent layers. Suitable amplifiers clutch are, in particular, vaccinated and/or linear copolymers, these copolymers can also contain more than two types of monomers, for example, Monomeric group of ethylene and/or propylene and structural units from the group comprising (meth-)acrylic acid, esters of (meth-)acrylic acid, vinyl acetate and/or anhydride is maleic acid. Especially preferred are, in particular, polyethylene grafted with maleic acid anhydride (LLDPE-g-MAA)copolymer of ethylene and a complex ester of acrylic acid, and SOP is limer ethylene-vinyl acetate (EVA). These polymers may be contained in the layers HV individually or in a mixture. In addition, layers HV can contain other polymers, for example polyethylene and/or other additives and/or pigments.

Layers HV can be excluded with sufficient own clutch between the functional layers, for example, that often occurs between the polyamide and many EVOH or by the insertion of components that increase grip, in a mixture of components, for example, the intermediate layer (B).

Differences in the structure, the structure and/or composition of the individual layers may independently from each other to be insignificant or, on the contrary, distinct. The transitions between the layers from the edge of one layer to the boundary of another layer independently from each other can be clearly or poorly expressed or to be smooth. The boundary layer can be almost flat or quite rough due to the neighboring large particles or clusters of particles, and possibly also in case of strong deviations in the thickness of the individual layers. Particularly preferably, one of the layers, particularly the layer different from the layer (P), performed mechanical load-bearing function. If the carrier layer is a layer (B), this layer preferably has a thickness of at least 15 μm, particularly preferably at least 20 microns.

The outer layer (Z) and/or at least one layer (R) can kombinirov the ü with other these types of layers, to get different multilayer structures. In many implementations, it is important that under the outer layer (Z) was at least one layer that performs mechanical load-bearing function. Below is a list of sequences of layers, in which instead of (Z) for the outer layer the type of this layer. The preferred layer structure (explanation of abbreviations see above):

The outer side of the membrane: the Inner side of the shell:

1. A/R/A

2. In/R/A

3. With/P/

4. A/P/HV/B

5. A/P/HV/C

6. A/P/B/A

7. A/P/C/A

8. A/P/A/A

9. B/HV/P/A

10. C/HV/P/A

11. A/B/P/A

12. A/b/R/S

13. A/b/R/S/A.

14. A/P/A/HV/B

15. A/P/A/HV/A

16. A/C/R/V/a

17. A/HV/A/P/A

18. B/HV/C/P/A

19. And/R/And/R/

20. A/R/a/R/A

21. A/P/HV/P/A

22. A/P/P/HV/B

23. C/a/b/R/A

24. A/P/HV

25. A/P/HV/B/HV/A

26. B/HV/A/P/A/C

27. A/P/A/HV/B/HV/C

28. B/HV/P/HV/C/HV/A

29. A/R/A/a/a

Especially preferred are structures 1, 2, 4, 6, 13, 14, 15, 20 and 21. On the outer side of the shell is the outer layer (Z), and on the inner side of the inner layer (I). At least one layer (R) shell may have the structure or function of the layer (A), (B), (C) and/or (HV), with any combination of transitions between the two layers for the layer (B), as well as other kinds of layers, such as (Z) and (I). Layer (P), layer (A) or the layer (A) preferably combine with (B), (C) and/or (HV). Especially predpochtitel is about, to the layer (P) represented the first layer under the outer layer (Z) or represented the first or second layer in the shell, containing at least 5 layers, under the outer layer (Z).

Shell food than the layer (B) preferably contains at least one layer chosen from the group comprising the layer (A)containing a thermoplastic substance on the basis of one or more (co-)polyamides layer (b)containing the polyolefin(s)and layer (C), representing a barrier to oxygen and other gases, and at least one layer (HV), which is an intermediate and/or inner layer, enhancing grip.

Wrapper for food products preferably includes at least one layer (A)containing a thermoplastic substance on the basis of one or more

(co-)polyamides, at least one supporting layer, which is an intermediate layer, at least one layer (b)containing the polyolefin(s), at least one layer (C), representing a barrier to oxygen and other gases, and/or at least one layer (HV), which is an intermediate and/or inner layer, enhancing grip.

Wrapper for food products preferably includes at least one layer (A)containing a thermoplastic substance on the basis of one or more

(co)polyamides, and at least one layer of the following: at least one layer (b)containing the polyolefin(s), at least one layer (C), representing a barrier to oxygen and other gases, and/or at least one layer (HV), which is an intermediate and/or inner layer, enhancing grip.

Shell food along with the outer layer (Z) preferably includes at least one layer (A)containing a thermoplastic substance on the basis of one or more (co-)polyamides, and at least one layer (HV), which is an intermediate and/or inner layer, enhancing grip.

Preferably at least one layer (B) is a layer (A)containing a thermoplastic substance on the basis of one or more (co-)polyamides.

Preferably at least one layer, in particular a layer not containing coarse particles, or, in particular, the middle layer performs carrier function and has a content of thermoplastic components based on one or more (co-)polyamides more than 50% by mass.

The objective of the invention is also solved using the method of manufacturing the casing for food products according to which is made at least three thermoplastic mass, which soften and/or at least partially melted during soak is trutii, receiving at least three layers, which are processed into a solid film in the form of essentially tubular shell, and whereby at least one mass, which is used for producing the layer (P), located in the middle part of the layered structure between the outer layer (Z) and inner layer (I), add inorganic and/or organic coarse particles, and at least one kind of particles has an average size of the dso at least 5 microns.

Produce a mixture of a thermoplastic polymer matrix and inorganic or organic particles to the receiving layer (B) can be performed, for example, at the stage of preparation of the composition of one of the known methods. Then you can spend coextrusion in the form of extrusion of the sleeve. The above materials as necessary added to the mass during mixing or stirring and generally uniformly or substantially uniformly distributed in the composition, intended for obtaining the corresponding layer. In the extrusion process sleeves all layers simultaneously formed in coextruded annular nozzle and thereafter connect and meld into one seamless multilayer film in the form of a tubular sleeve.

The manufacture of casings for food products having the above described structure, carried out by means of coextrusion, preferably with the next blow sleeves or biaxial stretching of the sleeve. Appropriate methods known to experts in this field of technology.

A mixture containing inorganic and/or organic particles and polymer matrix, as well as other appropriate polymers or mixtures thereof, usually melted in separate extruders, and then unite in a heated co-extrusion ring to the injector. The output is formed molten film annular workpiece, consisting of several layers, which can directly inflate to get sleeves or expose duociau stretching and subsequent heat setting. In the latter case, the molten film, usually by rapid cooling attach to amorphous sleeve, then heated to about 80°C and stretch (i.e. oriented in the direction of two axes by means of an air cushion enclosed between two pairs of wringer rollers. You can then take the heat setting, which stretched the sleeve is passed through the following heating zone with a possible stabilization by means of the second airbag. Thus, the tendency of the shell to heat shrinkage is reduced to a practically acceptable value, which is usually from 5 to 20% in the longitudinal and transverse direction and is measured at 80°C. And finally the shell is made according to the invention, can be processed, that is s get cut, tied with one hand, the corrugated tube shape similar to the intestinal membrane, in particular the shell of the colon or rectum. Such a sheath can be used as packaging for food products, particularly dairy or sausage products, preferably as an artificial sausage casings.

The casing for food products according to the invention have the following features:

1) the Process of making the membrane more stable and allows you to get high quality, if you do not enter coarse particles directly into the outer layer (Z) and inner layer (I), and add them in at least one corresponding weight, which is intended for the manufacture of the intermediate layer. If coarse particles, in contrast, are located in the outer layer (Z), they usually quickly form deposits on the edge of the nozzle, which can interfere with the production process. In the first experiments have established that the mass of sediment is almost inversely proportional to their hardness or hardness of the particles. Deposits of coarse organic particles often have a thickness greater than the deposits of coarse-grained inorganic particles. Deposits in the form of a system containing polyamides, can be at least partially due to the collapse of nahodyawegosya composition, decomposed and/or burning of organic material, for example low molecular weight polyamide, which can be formed during manufacture of the initial mass, in particular, on the basis of the filler (i.e. particles) and polyamide. In the case of the use of coarse organic particles such deposits may occur at least partially due to the combustion products of organic particles. If coarse particles are not contained in the outer layer (Z) and in the inner layer (I) and the edge of the nozzle does not come into direct contact with the layer containing particles, such at least partially burned material forms deposits to a lesser extent or not at all their forms.

1A) Deposits on the injector lead primarily to the so-called variance value caliber, i.e. degrade the uniformity of the diameter of the tube. They significantly reduce the effective cross section of the nozzle and thereby cause deflection of the diameter (caliber) of the sleeve, the resulting extrusion. For example, the first portion of the sleeve has a diameter of 47 mm, the next part 46 mm, then again 47 mm, etc. It is a serious problem.

1B) Deposits can at least partially be removed without stopping the extruder. However, you can easily damage the workpiece. If the stop process, the need to the ora may occur every 5-10 minutes, deposition, as a rule, you can remove by erasing from the edge of the co-extrusion nozzle, and then resume the process. Thus extruded billet is often necessary to cut off and discard too short, and partially defective pieces of shell length from 50 to 450 m With a slight sediment or their absence the manufacturing process runs more stable and lower percentage of marriage, as the process does not need to be stopped to remove the deposits, which in the extrusion process cannot be removed or can be removed only partially.

1B) If deposits are not removed, their accumulation can reach such magnitude that some of the sediment will be captured by the extruded film and even intrude into the film. In such places the film breaks easier, and then also terminates. These defective areas in the shell are invalid, so the relevant section of the shell you want to reject. The breakdown of the shell due to trapped or embedded in the shell deposits periodically occurs because at orientation, as a rule, there are pressures from 1.5 to 2.5 bar.

2) film Surface is less abrasive, if coarse particles are not directly in the outer layer (Z) and not directly in the inner layer (I)and at least one secondary SL is EB. In many embodiments of coarse particles, although they are at least in one of the middle layers are at least partially flat surface of the outer layer (Z) and/or the inner layer (I) together at least partially with one inner layer that surrounds these coarse particles. In these implementations, they are disconnected or often surrounded by a thin polymer film. Thus it is possible to reduce the wear and tear of machinery, auxiliary products and tools, such as knives and/or rubber sponges, for example, when filling the casings of sausage meat. It is primarily concerned with membranes that contain coarse inorganic particles, and to a lesser extent membranes with organic particles.

3) the Presence of coarse particles in the shell according to the invention makes it easier to remove, tear and bursting shell, filled food product.

4) If one of the outer layers, in particular the outer layer (Z)contains at least one matting agent, it is not only rough, but matte outer surface of the shell. The same applies to the inner layer.

Thus, a relatively simple method failed to obtain a homogeneous membrane with highly rough and matte surface is Yu at high process stability, a low level of defects and ensuring great accuracy.

It was possible to produce casings for food products, largely similar to the natural intestinal, collagen, skin-fibrous and cellulosic membranes, reinforced fibers, while coarse particles, although not located in the outer layer (Z), however, give a high surface roughness of the shells.

It was possible to produce membranes with a rough matte surface, in which coarse particles are not in the outer layer (Z), and in one of the other layers, while the outer layer (Z) contains a matting agent. If coarse particles are in the outer layer (Z), in many cases, about every 5 minutes on the injectors appear fat. If these particles are in one of the middle layers, deposits of the same amount are often formed only after 500 minutes or more than 8 hours.

It turned out that the shell that contains only average size of organic particles, does not contain large inorganic particles and very poorly soluble in a mixed phase or not soluble at all, has a much more matte look than the shell, which is as large particles contains only coarse inorganic particles.

When the minimum level of implementation and comparative examples

Further properties of the membranes according to the invention are explained on the examples of implementation options.

Example 1

The sleeve of wollastonite and RA, stretched in the direction of two axes and thermophysiology

By way of coextrusion using five single-screw extruders and installed at the output co-extrusion ring nozzle, made of five-layer tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) intermediate layer (HV), consisting of a clutch based on LLDPE grafted MSA (Modic-AP^®L513),

in another intermediate layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34),

g) another intermediate layer (R=A)consisting of a composition made in co-rotating twin screw mixer of 85% by weight of polyamide RA (Grilon^®F34) and 15% by weight of wollastonite (Tremin^®283 100 EST)

d) the outer layer (Z=A), consisting of 100% by weight of polyamide RA (Grilon^®F34).

Powdered wollastonite added to the layer d), had an average particle size of 8 microns and a wide size distribution with d₉₅about 50 μm and a maximum particle size of about 70 microns. Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range from 50 to 70 microns. While about 10% were in the inner layer (a), about 30% for the intermediate layer (b), about 30% for the intermediate layer), about 20% for the intermediate layer g) and about 10% for the outer layer d). The structure of the shell corresponds to the above scheme A/HV/A/P/A. Layer (R) was the only layer that contains particles. This layer (R) attached to the membrane roughness and haze: the shell had been little gloss surface and high surface roughness (see table 1). When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during short-term production tests visible wear rubber jaws and knives were not observed.

Example 2

The sleeve of cellulose and polyethylene, stretched in the direction of two axes and thermophysiology

By way of coextrusion using four single-screw extruder and installed at the output co-extrusion ring nozzle, made a four-layer tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% p is the weight of the polyamide RA (Grilon ^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) an intermediate layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34),

in another intermediate layer (B)consisting of a composition made in co-rotating twin screw mixer of 54% by weight of polyethylene LDPE (Escorene^®LD165BW), 40% by weight of the clutch based on LLDPE grafted MSA (Modic-AP^®L513), and 6% by weight of cellulose powder (Jelucel^®PF90), while between the types of layers (b) and (HV) there was a transition, and

d) the outer layer (Z=A), consisting of 100% by weight of polyamide RA (Grilon^®F34).

The average particle size of cellulose powder in layer (b) was about 32 μm, the maximum particle size was about 110 μm. Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range from 55 to 75 microns. However, about 15% were in the inner layer (a), about 50% for the intermediate layer (b), about 25% for the intermediate layer) and about 10% for the outer layer d). The structure of the shell corresponds to the above the Hema And/And/R/A. When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during the production testing of visible wear rubber jaws and knives were not observed.

Example 3

The sleeve of wollastonite and RA, stretched in the direction of two axes and thermophysiology

By way of coextrusion using three single-screw extruder and installed at the output co-extrusion ring nozzle, made of three-ply tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) an intermediate layer (A), which served also as a layer (P) and consisted of a composition made in co-rotating twin screw mixer of 85% by weight of polyamide RA (Grilon^®F34) and 15% by weight of wollastonite (Tremin^®283 100 EST; (d₅₀=8 ΜM AND (d₉₅=50 μm), and

C) the outer layer (HV), consisting of 50% by weight of the clutch based on LLDPE grafted MSA (Modic-AP^®L513), 40% by weight polyethylene LDPE (Escorene^®LD165BW) and 10% by weight of wollastonite as a matting tools (Tremin^®283 600 AST; d₅₀=3.5 µm and d₉₅=13 μm).

The wollastonite added as a matting tools, had a rather narrow distribution of particle sizes, while his cropnosis is made of particles had a fairly wide size distribution. Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range of 45 to 65 μm. However, about 60% were in the inner layer (a), about 30% for the intermediate layer (b) and about 10% for the outer layer). Layer (R) was the only layer that contained particles larger than 18 μm. The shell had been little gloss surface and high surface roughness (see table 1). The structure of the shell corresponds to the above scheme A/P/HV. When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during short-term production tests visible wear rubber jaws and knives were not observed.

Example 4

The sleeve of starch, glycerol and RA, stretched in the direction of two axes and thermophysiology

By way of coextrusion using three single-screw extruder and installed at the output co-extrusion ring nozzle, made of three-ply bag the title is ovcu, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) an intermediate layer (A), which served also as a layer (P) and consisted of a composition made in co-rotating twin screw mixer of 50% by weight of polyamide RA (Grilon^®F34), 30% by weight of powdered maize starch and 20% by weight of glycerin, and

C) the outer layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34).

The distribution of particle size was in the range of 5 to 35 μm, the average particle size d₅₀was about 18 microns. Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range of 45 to 65 μm. However, about 60% were in the inner layer (a), about 30% for the intermediate layer (b) and about 10% for the outer layer). Layer (R) was the only layer that contains particles. The shell had a very low surface gloss and high roughness (see table 1). Taka is the structure of the shell corresponds to the above scheme a/R/A. When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during short-term production tests visible wear rubber jaws and knives were not observed.

Due to the presence of glycerol starch was plastifitsirovanie and become thermoplastic. He was also chemically compatible with the polyamide and formed with polyamide mixed phase as a matrix, and the particle content of the starch was decreased. Although the content and size of coarse organic particles is significantly decreased, the appearance of the shell with gloss equal to 4, was very good. Probably in this case is influenced by the structure of the shell with frequent, distinct changes of the refractive index.

Example 5

Permeable sleeve of wollastonite and RA, stretched in the direction of two axes and thermophysiology

Preparation of a composition based on polyvinyl alcohol:

In a reactor with a stirrer and a jacket with a heated liquid at room temperature has uploaded 75% by weight of polyvinyl alcohol (Mowiol^®26-88, Hoechst AG). Then, under stirring at a speed of about 1000 rpm added first 15% by weight of polyethylene glycol, and then to 7.5% by weight of glycerol and 2.5% by weight of water (relative to the total mass of the CME is and). The contents of the reactor was heated to 100-110°C, was mixed at this temperature for 15 minutes and further stirring was cooled to 30-40°C. the resulting powder using a dosing device introduced into a heated twin screw mixer with a cylinder diameter of 25 mm and a ratio of length to diameter 36 through a single nozzle in such a way as to obtain a flow of mass 8 kg/hour. The rotation speed of the screws was 250 rpm Heaters from the boot configured to increase the temperature of the downstream flow in the direction of the nozzle from 120°C to 180°C. Leaving a transparent filament is cooled in the area of air cooling, and then cut using a grinder, having granules.

Manufacturing of a sleeve way of coextrusion:

By way of coextrusion using three single-screw extruder and installed at the output co-extrusion ring nozzle, made of three-ply tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight of the composition of the polyvinyl alcohol,

b) intermediate layer (R=A), which consisted of 75% by weight RE (Grilon^®F34), 20% by weight of the composition based on polyvinyl alcohol (PVAL) and 5% by weight of wollastonite (Tremin^®283 100 EST; d₅₀=8 μm and d₉₅=50 μm), and

C) the outer layer (Z=A), which is 80% by weight of polyamide RA (Grilon ^®F34) and 20% by weight of the composition based on polyvinyl alcohol.

Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range from 50 to 70 microns. However, about 60% were in the inner layer (a), about 30% for the intermediate layer (b) and about 10% for the outer layer). The structure of the shell corresponds to the above scheme a/R/A. Layer (R) was the only layer that contains particles. This layer (R) attached to the membrane roughness and haze: the shell had been little gloss surface and high surface roughness (see table 1). When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during the production testing of visible wear rubber jaws and knives were not observed. Polyvinyl alcohol swells upon contact with water, holding the water in the shell and serves as a conductive medium for water and steam.

Example 6

The sleeve with coarse particles and atroushi means of wollastonite and RA, stretched in the direction of two axes and thermophysiology

By way of coextrusion using five single-screw extruders and installed at the output co-extrusion ring nozzle, made of five-layer tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) intermediate layer (HV), consisting of a clutch based on LLDPE grafted MSA (Modic-AP^®L513),

in another intermediate layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34),

g) another intermediate layer (R=A)consisting of a composition made in co-rotating twin screw mixer of 90% by weight of polyamide RA (Grilon^®F34) and 10% by weight of wollastonite (Tremin^®283 100 EST; d₅₀=8 μm and d₉₅=50 μm) and

d) the outer layer (Z=A), consisting of 90% by weight of polyamide RA (Grilon^®F34) and 10% by weight of wollastonite used as matting tools (Tremin^®283 600 EST; d₅₀=3.5 µm and d₉₅=13 μm).

Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was when the Arno 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range from 55 to 75 microns. While about 10% were in the inner layer (a), about 30% for the intermediate layer (b), about 30% for the intermediate layer), about 20% for the intermediate layer g) and about 10% for the outer layer d). The structure of the shell corresponds to the above scheme A/HV/A/P/A. Layer (R) was the only layer that contained coarse particles, the layer (Z) - contrast, fine particles as a matting tools. The shell was very rough and matte (see table 1). When stretching along two axes of the shell is not damaged. Deposits in the jet was almost absent, and during the production testing of visible wear rubber jaws and knives were not observed.

Example 6 in contrast to example 1 is characterized by the use of matting means in the outer layer (Z), while in the rest of the shell in both examples were fabricated the same way and have the same structure. Mechanical and other properties of these two shells are pretty close.

Unlike shell, described in comparative example 2, which was manufactured in the same way and had the same structure, except that in example 6 coarse particles of wollastonite find the of n in the outer layer (Z) of the shell, and not in the intermediate layer (B), and that the outer layer (Z) contain matting agent, all the mechanical properties of the samples of example 6 were significantly higher than in comparative example 2.

Example 7. Manufacturer inflated sleeves from wollastonite, maize starch and RA

By way of coextrusion using three single-screw extruder and installed at the output co-extrusion ring nozzle, made of three-layer inflated sleeve, which included:

a) an inner layer (I=A), consisting of 100% by weight of polyamide RA (Grilamid^®L25),

b) intermediate layer (R=A), which consisted of a composition made in co-rotating twin screw mixer of 72% by weight of polyamide RA (Grilon^®F34), 20% by weight of maize starch and 8% of wollastonite (Tremin^®283 100 EST; d₅₀=8 μm and d₉₅=50 μm), and

C) the outer layer (Z=A), consisting of 100% by weight RE (Grilamid^®L25).

After the release of the various layers of the coextruded annular nozzle sleeve inflated outside diameter by forcing air into the inner sleeve, and then pass through two pairs of rollers. The diameter of the inflated sleeve was 90 mm and a total wall thickness lying in the range from 90 to 110 μm. However, about 50% were in the inner layer (a), about 40% of the intermediate layer (b) and about 10% for the outer layer). The structure of the shell sootvetstvuyushiye scheme a/R/A. Layer (R) was the only layer that contains particles. This layer (R) gave the shell a special roughness and haze: the shell differed very low surface gloss and high roughness (see table 1). In the process of inflating the casing is not damaged. Deposits in the jet was almost absent, and during the production testing of visible wear rubber jaws and knives were not observed. The starch particles have not been plasticized and, therefore, thermoplastic, so they probably do not form a mixed phase with the surrounding organic matter.

Comparative example 1

(Sleeve, not containing particles, stretched in the direction of two axes and thermofixation)

The method described in examples 1-6, manufactured stretched in the direction of two axes thermophysiology three-layer sleeve, which included:

a) an inner layer (A)consisting of 85% by weight of polyamide RA (Grilon^®F34) and 15% by weight PA6I/6T (Grivory^®G21),

b) not containing particles of the intermediate layer with the properties of the layers (b) and (HV), which, however, did not serve as a layer (P) and consisted of 50% by weight of polyethylene LDPE (Escorene^®LD165BW)mixed with 50% by weight LLDPE grafted MSA (Admer^®NF518E), as the clutch, and

C) the outer layer (A)consisting of 100% of massarina RA (Grilon ^®F34).

The diameter thermofixing sleeve was about 70 mm and a total wall thickness lying in the range from 40 to 60 μm. However, about 20% were in the inner layer (a), about 40% of the intermediate layer (b) and about 40% for the outer layer). Unlike the previous examples, the shell described in comparative example 1 did not contain coarse particles. Particles were absent in all layers. Therefore, this shell was much more smooth and glossy than the shell according to the invention (see table 1). However, due to the absence of particles, the mechanical properties of the film has improved: it has become less brittle and had a higher tensile strength and higher elongation at break. The structure of the shell corresponds to the above scheme a/R/A. Under tension in the direction of two axes, the shell is not damaged. Deposits in the jet was almost absent, and during the production testing of visible wear rubber jaws and knives were not observed.

Comparative example 2

The sleeve containing coarse particles (wollastonite) only in the outer layer (Z), stretched in the direction of two axes and thermophysiology

The method described in examples 1-6, using five single-screw extruders and installed at the output co-extrusion ring nozzle, manufactured Patisson the Yu tubular workpiece, which included:

a) an inner layer (I=A), consisting of 80% by weight of polyamide RA (Grilon^®F34) and 20% by weight PA6I/6T (Grivory^®G21),

b) intermediate layer (HV), consisting of a clutch based on LLDPE grafted MSA (Modic-AP^®L513),

in another intermediate layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34),

g) another intermediate layer (A)consisting of 100% by weight of polyamide RA (Grilon^®F34),

composition made in co-rotating twin screw mixer of 85% by weight of polyamide RA (Grilon^®F34) and 15% by weight of wollastonite (Tremin^®283 100 EST)

d) the outer layer (Z=A)consisting of a composition made in co-rotating twin screw mixer of 85% by weight of polyamide RA (Grilon^®F34) and 15% by weight of wollastonite (Tremin^®283 100 EST).

Tubular workpiece is quickly cooled to about 20°C and then heated to about 80°C. and stretched at this temperature in the direction of the two axes when the drawing ratio of the surface of a 9.25. In the next zone heating the sleeve was subjected to heat-setting, after which thermal shrinkage, measured in water at 80°C, was approximately 10-12%. The diameter thermofixing sleeve was 70 mm and a total wall thickness lying in the range from 50 to 70 microns. While about 10% were in the inner layer (a), about 30% for the intermediate layer (b), about 30% for the intermediate layer), about 20% appromiately layer g) and 10% on the outer layer d). The shell had been little surface gloss and a very large roughness (see table 1). The structure of the shell corresponds to the above scheme A/HV/A/A/P. None of the layers except the layer (Z) does not contain particles. There were deposits of great thickness, which interfered with the process already after 5 minutes, however, during short-term production tests did not cause visible wear, rubber sponges and knives. Deposits in the jet is very often led to deviations of the value caliber stretch shell in the direction of two axes, often captured and implemented deposits manifested as inclusions in the film and sometimes rupture of the film.

As follows from table 1, the casing for food products according to the invention manufactured by the above-described method differs significantly from the traditional shells from the point of view of surface properties due to the presence of the intermediate layer (B), which contains inorganic and/or organic particles.

The size distribution of inorganic particles was determined using a laser granulometer in dilute aqueous suspension. The roughness was determined according to DIN 4762, ISO 4287/1 and DIN 4762/1 E using pentametre S5P with perten-probe RTH6/50E 110457 (Diamond) with a measuring range of 0.8 mm. The arithmetic mean deviation of the profile R_arepresents the arithmetic average of all departures of the roughness profile from the mean line within the controlled area. The average height of asperities profile R_zrepresents the average value of the individual heights of asperities on five successive sections of the length by 5 mm in the microrelief. The maximum height of asperities of the profile Rmax is a maximum of five average heights of asperities. The roughness values were averaged according to the results of 5 measurements. The more the obtained values, the more rough the surface.

Indicator gloss was determined according to DIN 67530, ISO 2813 and ASTM D 523 at an angle of incidence of the beam 60° using Micro Glass 60 by BYK Gardner. While photovoltaic way measured radiation reflected from the surface. The lower the figure the Shine, the more matte the surface.

Mechanical properties, in particular tensile strength, elongation at break values of Sigma 5 and Sigma-15, was determined according to DIN 53455 on sections of the membranes using a universal machine for testing. When the test samples of example 7 were dry, while the samples of all other implementation examples and comparative examples were wet, all segments is bolecek had a width of 15 mm, and the clamping length of the test samples was 50 mm tensile Strength represents the amount of strength at the initial moment of rupture. Elongation is the elongation at the initial moment of rupture, which is a measure of the fragility of the shell. Values of Sigma 5 and Sigma 15 mean force applied when the elongation of the membrane at the 5% or 15%.

All implementation examples and comparative examples, the tensile strength was from good to very good. As can be seen from comparative example 1, the presence of coarse particles, obviously, decreases, however, when the results of measuring the strength should not expect any difficulties to fill the shells with the weight of food.

All implementation examples and comparative examples, the tensile elongation was good to very good. As can be seen from comparative example 1, the presence of coarse particles, obviously, reduces it, however, when the measured values of the elongation at break should not expect any difficulties to fill the shells with the weight of food. Not subjected to stretching, obtained by the method of the bulge of the sleeve in example 7, by contrast, had a very high elongation at break due to smaller relative orientation of the molecules, i.e. due to practical disorder thermoplastic polim the ditch in the film and a relatively low crystallinity.

All values of Sigma 5 and Sigma 15 were good or very good. The higher these values are, the better the mechanical properties.

Determination of permeability (WDD) was produced according to DIN 53 122. When this segment of the shell tightly stretched over the Cup containing the desiccant was placed in a cell for climatic tests and gave with one hand still air with a relative humidity of 85% at 23°C. the Full weight of the Cup shell, drying and sealing wax was determined before and after exposure in the camera for climatic tests.

Shell according to the invention had the appearance, especially similar to collagen membrane.

1. Tubular multilayer thermoplastic casing for food products that include the outer layer (Z), inner layer (I) and at least one located between the layer (P), characterized in that the layer (P)located between the outer layer (Z) and inner layer (I)contains more than 50% by weight of at least one thermoplastic polymer and coarse inorganic and/or organic particles, at least one kind of coarse particles has an average equivalent diameter of the ball d₅₀more than 5 μm, and the surface of the outer layer (Z) and/or the inner layer (I) has an average height R_zroughness profile p is at least 5 μm by averaging the results of 5 measurements.

2. Casing for food products according to claim 1, characterized in that the coarse particles of at least one layer (B) have such distribution and frequency that an average of at least three particles in one mm²the outer and/or inner surface have a diameter and are located in the membrane in such a way that they at least partially protrude from the flat surface areas due to the swelling of the main mass around these particles and/or at the expense of the particles protruding from the main mass.

3. Casing for food products according to claim 1 or 2, characterized in that at least one layer (B) contains at least 0.05% by volume of inorganic and/or organic particles with equivalent diameter of the ball at least 10 μm or volume of particles of at least 524 μm³.

4. Casing for food products according to claim 3, wherein the combination of inorganic and/or organic particles of at least one layer (B) or at least its essentially isometrically formed particles have an equivalent diameter of the ball within the 20 to 40 microns.

5. Casing for food products according to claim 4, characterized in that at least one layer (B) contains at least 0.5% by weight of inorganic and/or organic particles.

6. Casing for food products according to one of claims 1 and 2 or 4 and 5, the ex is different, however, as inorganic particles mainly or largely consist of particles on the basis of aluminum oxide, carbonate, phosphate, silica, silicate, sulfate, rocks and/or glassy substance.

7. Casing for food products according to one of claims 1 and 2 or 4 and 5, characterized in that the organic particles predominantly or largely consist of particles on the basis of polysaccharides, proteins and/or polymers that are resistant to high temperatures.

8. Casing for food products according to one of claims 1 and 2 or 4 and 5, characterized in that the surface of the outer layer (Z) is the indicator gloss was measured using the Micro-Gloss 60 by BYK Gardner and averaged over 5 measurements, not more than 65.

9. Casing for food products according to one of claims 1 and 2 or 4 and 5, characterized in that, along with at least one layer (B) it contains at least one layer selected from the group comprising layers (A)containing a thermoplastic substance on the basis of one (co-)polyamide or more (co-)polyamides, layer (C)containing the polyolefin(s), and the layers (C)blocks the penetration of oxygen and other gases, and optionally at least one layer (HV), which is the intermediate or inner layer, enhancing grip.

10. Casing for food products according to one of PPI 2 or 4 and 5, characterized in that at least one layer (B) is a layer (A)containing a thermoplastic substance on the basis of one (co-)polyamide or more (co-)polyamides.

11. Casing for food products according to one of claims 1 and 2 or 4 and 5, characterized in that at least one layer, in particular the outer layer (Z) and/or the inner layer (I)comprises at least one matting agent.

12. A method of manufacturing the casing for food products according to one of claims 1 to 11, according to which is made at least three thermoplastic mass, which soften and/or at least partially melt during the extrusion, while receiving at least three layers, which are processed into a solid film in the form of a seamless, essentially, of a tubular shell, and whereby at least one mass, which is used for producing the layer (P), located in the middle part of the layered structure between the outer layer (Z) and inner layer (I)add inorganic and/or organic coarse particles, and at least one kind of particles has an average size of d₅₀at least 5 microns.

13. The method according to item 12, wherein at least one layer, particularly a layer that does not contain coarse particles, or, in particular, the intermediate layer, performs nasoduodenal and has a content of thermoplastic components on the basis of one (co-)polyamide or more (co-)polyamides more than 50% by mass.

14. The method according to item 12 or 13, characterized in that the coarse particle mass in the extrusion process are embedded in a thin layer of the shell, while the layered structure has swelling around coarse particles.

15. The method according to one of p and 13, characterized in that the organic compounds that are added to the mass, are largely or completely heat-resistant at the temperature of extrusion.

16. The method according to item 15, wherein the organic particles at least partially plastificator at least one plasticizer and thereby make them at least partially of thermoplastic, with organic particles form a mixed phase of at least part of at least one substance of the main mass and when this happens their surface softening and/or at least partial dissolution.

17. The method according to one of p, 13 or 16, characterized in that the shell at the end of its production can be processed to get cut, tied with one hand, the corrugated tube shape similar to the intestinal membrane, in particular the shell of the colon or rectum.

18. The use of membranes according to one of claims 1 to 11 as packaging for food products, particularly dairy or sausage products, preferably as artificial is Oh sausage casings.