Layered packaging materials and derived containers

 

The invention relates to the field of production of laminated packaging materials and provides good proof packaging for oxygen. Upon receipt of laminated packaging material forming the inner layer of paper or cardboard and the barrier layer deposited on one side of the inner layer. The barrier layer is formed by coating film on at least one side of the base layer and dried by heating for removing water. After this base layer coated with the dried barrier layer are combined and continuously connected to one side of the inner layer. 5 S. and 26 C.p. f-crystals, 1 tab., 12 Il.

The invention relates to methods for laminated packaging material containing an inner layer of paper or cardboard and a barrier layer applied at least on one side of the inner layer.

The present invention also relates to a laminated packaging material obtained according to this method, and packaging containers produced from laminated packaging material. Especially preferred packaging laminates, in which the barrier layer is applied starch or its production is Arial disposable packaging and transportation of liquid food products. Typically, these layered packaging materials made of hard in a specific configuration, but bendable inner layer consisting, for example, of paper or paperboard, to obtain good mechanical stability of the configuration. On both sides of the inner layer are applied impervious to liquid coating of plastic material, effectively protect the inner layer of the absorbing liquid fibrous material from penetrating through it of moisture. These outer layers are usually composed of a thermoplastic, preferably polyethylene, which, in addition, gives the packaging material increased performance thermoclean, whereby the packaging material can be folded in the completed package with the desired geometric configuration.

However, laminated packaging material, consisting only of paper or cardboard and is impervious to liquid plastic, does not have sufficient impermeability to gases, in particular oxygen. This is a major flaw in the packaging of many foods, shelf life which is sharply reduced when in contact with oxygen. To provide the packaging material barrier to gases, in particular oxygen, is pronitsaemosti, for example, aluminum foil or polyvinyl alcohol, on the other side of the inner layer, which should be facing the inside of the packaging.

Compared with aluminum foil, polyvinyl alcohol has many desired properties, with the result that he preferred as a barrier material in many environments. Among them may be mentioned high strength polyvinyl alcohol, compatibility with food products and low cost along with superior characteristics kislotonepronitsaemost. In addition, it is considered appropriate to replace the aluminum foil as a barrier material for gas in the packaging of food products from the point of view of protecting the environment and recycling.

Like many potential barrier or adhesive polymers, such as, for example, ethylene vinyl alcohol, starch, starch derivative, carboxymethylate cellulose and other cellulose derivatives, or mixtures thereof, polyvinyl alcohol is conveniently applied by spraying, i.e. in the form of a dispersion or of an aqueous solution, which when applied is dissipated in the form of a thin uniform layer on the substrate and then dried. However, it was discovered that one of the drawbacks is the addition ethylenically acid, which is applied on the inner layer of paper or cardboard, enters the absorbing liquid fiber of the inner layer. In connection with the removal of water for drying and curing the applied barrier layer, the inner layer is also exposed to elevated temperatures for drying and, as a result, the risk of unwanted formation of cracks in a paper or cardboard layer, respectively, increases due to moisture content, which is difficult to regulate, and drying produced in this layer.

In the patent Sweden 440519 proposed the inclusion in the material of thickener, such as alginate thickener, to reduce the penetration of water into the cardboard. The use of polyvinyl alcohol as a barrier material deposited on the polymer layer, thus preventing the formation of cracks and smoothing the surface of the cardboard, was described in the application PCT/SE96/01237.

One disadvantage is that polyvinyl alcohol is sensitive to moisture and quickly loses its barrier properties when it is exposed to moist environment. This deficiency was previously eliminated in international publication WO 97/22536, a combination of polyvinyl alcohol with one or more known, approved for use with Pedavena. It mainly forms, in combination with polyvinyl alcohol related, well-integrated layer having superior characteristics for gas-tightness, in particular the characteristics kislotonepronitsaemost, with the necessary high characteristics on the permanence of polyvinyl alcohol preserved even in a wet environment.

In the publication WO 97/22536 stated that polyvinyl alcohol mixed with a copolymer of ethylene and acrylic acid or a similar substance, may be applied in the form of dispersion on cardboard, pre-coated with polymer, and then can be dried and vulcanized at temperatures up to 170oFor the formation of the laminated packaging material with very good barrier properties.

Another disadvantage of using, for example, polyvinyl alcohol as a barrier layer instead of aluminum foil is that when storing sensitive to light food in many cases it is also necessary to include in the packing material of a certain type barrier to light. It is assumed that the inner layer of paper or paperboard not skipping (to the naked eye) light, but the light evomo product and may have a negative impact on it from the point of view of the retention period. The use of aluminum foil in the packaging material provides the advantage that aluminum foil is, in itself, is a good barrier for gases and light. On the other hand, polyvinyl alcohol is completely transparent even in mixtures with hydrophobic polymer such as a copolymer of ethylene and acrylic acid or a copolymer of styrene and butadiene. The use of admixtures usual barriers to light, such as carbon black and titanium dioxide, in any of the plastic layers included in the laminated packaging material according to the publication WO 97/22536, it would be possible, but it would receive aesthetically unappealing appearance of the package.

Another disadvantage inherent in the laminated packaging material comprising barrier layers, for example, polyvinyl alcohol, perhaps in conjunction with another polymer, as described in the publication WO 97/22536, is that the packing material can not be made using the same production equipment, which is used for the production of packaging material with aluminum foil as a barrier layer, which will lead to capital investments in new production equipment.

As noted in the addition to such synthetic materials was investigated the possibility of using as a barrier to gas natural and biodegradable polymers (biopolymers), such as starch and derivatives of starch.

It is known that starch has certain characteristics for gas-tightness when used in relatively thick layers, such as films having a thickness of about 20-30 μm. However, such thick layers of starched material unsuitable for use in laminated packaging materials, as they become brittle and prone to cracking and fracture treatment, for example, in the process of applying layers and the bending of the laminate to obtain packages. In addition, they do not have the flexibility required for production and distribution, layered materials, including thick layers of starch were also able to absorb more moisture, which would adversely affect the characteristics of permanence.

From international publication WO 97/16312 known that very thin layers of starch deposited on the inner layer, can provide some of the characteristics of permanence, at least when used in conjunction with the adjacent layer of plastics, which is connected with starch barrier layer by applying a plastic material by extrusion method. Two very thin clinie side of the inner layer of cardboard and covered with a method of extruding a layer of plastic material, provide a barrier to oxygen efficiency 289 cm3/m224 hours at a pressure of 1 ATM. Similarly, two layers of starch applied in quantities of 1 and 1.5 g/m2accordingly, provides a barrier to oxygen efficiency 141 cm3/m224 hours at a pressure of 1 ATM. The results, therefore, were comparable with barrier properties to gas, for example, a film of oriented polyethylene of a thickness of 12 μm, thus presenting a barrier medium efficiency".

The packaging laminated material presented in publication WO 97/16312 is, however, only a gas-tight barrier average efficiency. This means that it can only be used for packaging liquid food products stored under refrigerated conditions for short periods of time. Up to the present time it was not known from the prior art packaging laminate having high performance characteristics in terms of permanence, made with the use of starch or starch derivative as barrier materials. It would be much more desirable to obtain a packing material having sufficient x is especiauy increased shelf life when stored under refrigerated conditions or even in aseptic storage. Such desirable characteristics of high efficiency kislotonepronitsaemost are within about 50 cm3/m224 hours at a pressure of 1 ATM (23oC and relative humidity 50%) or better, for example, up to 30 cm3/m224 hours at a pressure of 1 ATM, i.e. barrier properties for oxygen, comparable properties, for example, polyvinyl alcohol, copolymer of ethylene and vinyl alcohol or polyamides used with a thickness in the range of about 5 microns.

French patent 2684922 describes the coating of a polymeric film, such as polyester, dispersion of surface-active substances containing amelody starch, and drying of the starch at a temperature of up to 180oC. Good characteristics for gas-tightness receive when coverage levels, for example, 0.7 g/m2(dry matter). However, there is no mention of the fact that such quality can be obtained for the laminated packaging material having a paper or cardboard inner layer.

It was found that the laminated packaging material having adequate barrier properties, in particular against gases, can be produced using a method which is suitable for implementation using bachmaniii foil as a barrier layer.

Also found that you can get highly effective barrier properties for oxygen in the packaging laminated material through the use of starch and similar materials.

According to the first aspect of the invention, created a method of obtaining a laminated packaging material comprising the inner layer of paper or cardboard and the barrier layer deposited on one side of the inner layer, characterized in that the polymer dispersion or polymer solution is applied as a barrier layer at least on one side of the base layer and dried by heating for removing water, after which the bearing layer is coated with the dried barrier layer are combined and continuously connected to one side of the inner layer.

Preferably, the barrier layer is applied by spraying an aqueous polymer dispersion or solution. Polyvinyl alcohol may be applied as an aqueous solution, whereas the starch may be partly dispergirujutsja and partially dissolve in water.

The polymer preferably has a hydroxyl functional group and may be selected, for example, polyvinyl alcohol, ethylene vinyl alcohol, starch, starch derivatives, carboxymethyl cellulose and other production is unesenny as the barrier layer, can be dried and, if necessary, to be vulcanized at a temperature of from about 80 to 200oC. For devulcanizing materials, it is preferable to conduct the treatment at a temperature of from about 80 to 130oC.

Most preferably, materials such as polyvinyl alcohol, preferably first dried at temperatures paintings from 80 to 160oWith (preferably from 140 to 160o(C) during the first phase and then vulcanizer at temperatures paintings from 170 to 230oWith the second phase, resulting in an improved barrier for gas at a relative humidity of 80%. If necessary, supporting and barrier materials can be cooled between the two stages.

The polymer with functional groups carboxylic acid may also be included. It can react with the polymer with functional hydroxyl groups during drying/curing.

Properly polymer with functional groups carboxylic acid is selected from a copolymer of ethylene and acrylic or copolymers of ethylene and methacrylic acid or mixtures thereof.

One particularly preferred mixture for the barrier layer is a mixture of polyvinyl alcohol and FOSS higher temperatures so, that dried barrier layer is cured at a temperature of up to 230oWith, preferably approximately 170oC.

The specified barrier layer, preferably, is applied on the carrier layer in the amount of about 0.5-20 g/m2more preferably 2-10 g/m2(dry mass).

Supporting layer may consist of paper or plastic or paper coated with plastic, and preferred materials are described below.

According to one variant of execution of the supporting layer preferably consists of paper in the amount of approximately 15-35 g/m2for example 15-25 g/m2, more preferably 15 g/m2.

Base layer carrying the barrier material and the inner layer can be connected in different ways.

Base layer carrying at least one barrier layer, can be combined and connected with the inner layer by extrusion of a layer of thermoplastic located between them.

When the base layer carries the barrier layer on one of its sides, it is, thus, can be combined with the inner layer by extrusion of a layer of thermoplastic located between the carrier layer and inner layer.

The outer layer of thermoplastic, preferably p is the barrier layer on one or both sides, it can be combined with the inner layer by extrusion of a layer of thermoplastic located between the inner layer and barrier layer.

If the base layer carries the barrier layer on both sides, a layer of thermoplastic can, in this case, be applied to the outer layer of barrier material by extrusion.

The layer of plastic is applied between the inner layer and bearing layer or barrier layer may include a substance that acts as a barrier to light. This is especially preferable when the supporting layer is made of paper or other visually opaque material.

By applying during a separate manufacturing operation an aqueous polymer dispersion or polymer solution as a barrier layer on at least one side of the base layer and drying of the barrier layer when heated for the removal of water and subsequent combining and permanent connection carrier layer coated with the dried barrier layer on one side of the inner layer will be obtained laminated packaging material with a barrier layer with improved barrier characteristics.

Due to the fact that the barrier layer dried or vulcanized at elevated is nim layer and drying the inner layer of paper or cardboard with the following from this, the risk of formation of cracks in the inner layer is completely eliminated.

Given the condition that the plastic layer applied between the inner layer and the paper bearing layer may include a substance that serves as a barrier to light, ideally soot, you will receive a barrier to light, whose unattractive black view can be hidden in a layer located between the inner layer and a thin layer of paper, bearing the barrier layer.

One advantage of the method corresponding to this aspect of the present invention is that the barrier layer is performed during a single operation, can be used in the production of laminated packaging material appropriately and using the appropriate production equipment, as the production of packaging materials with aluminum foil as a barrier for oxygen at the present time.

Also found that you can get in layered packaging material properties of highly effective barrier to oxygen when using starch and similar materials.

Accordingly, the present invention creates a packaging laminate having a paper or cardboard inner layer and at least one gas-tight layer of starch or made the sa at a pressure of 1 ATM (23oC and relative humidity 50%) or better, and the specified gas-tight layer has a mass covering of dry matter or mass covering substances in aggregate state not more than 7 g/m2. Preferably, kislotonepronitsaemost provided with a layer of starch or starch derivative is 40 cm3/m224 hours at a pressure of 1 ATM (23oC and relative humidity 50%) or better. More preferably, kislotonepronitsaemost up to 30 cm3/m224 hours at a pressure of 1 ATM (23oC and 50% relative humidity), for example, 10 cm3/m224 hours at a pressure of 1 ATM (23oC and 50% relative humidity) or less than this value.

Preferably, the packaging laminate includes a layer of plastic polymer, preferably a thermoplastic, such as polyethylene, directly which caused the specified gas-tight layer. Most preferably, this polymer is low density polyethylene. Other thermoplastics that can be used include all other types of polyethylene (including linear low density polyethylene, three-dimensional low-density polyethylene, metallizirovanaya layer is applied with the amount of dry coating to 7 g/m2for example from 0.5 to 5 g/m2more preferably from 0.5 to 3 g/m2for example from 1.5 to 2 g/m2.

Preferably, the gas-tight layer was made entirely of natural materials, but it is permissible to include small amounts of other polymeric materials that do not degrade the required characteristics. For example, gas-tight layer can also include a small amount of water-soluble or water-dispersible polymers having functional hydroxyl groups, for example polyvinyl alcohol, polyolefins containing carboxyl group such as ethylenically acid, or their mixture. The number of such materials can vary from 0 to 30 weight. percent, for example, from 0 to 20 weight. % or from 0 to 10 weight. %.

It has been observed that when the polyethylene is applied to the layer of starch at high temperature, for example above 200oWith the characteristics of the starch on the permanence of increase, and that under appropriate conditions they can achieve high level of performance or to move higher. One preferred method of obtaining optimal performance is the application of starch or starch derivative is not on a thick inner layer, as the description of the case gas-tight layer is supported by the carrier layer of paper or plastic.

When paper is used, preferably, it should be fine, for example, the supporting layer may be made of paper in the range from 10 to 35 g/m2preferably from 10 to 25 g/m2. Paper can also pre-covered with a layer of plastic.

After applying the starch carrier can be combined with the material of the inner layer of paper or cardboard so that the packaging laminated material contained inner layer with specified supporting layer on one of its surfaces. Can be applied one or more layers including a heat-sealable layer on another surface of the inner layer.

The surface of the base layer, which is applied to the starch or starch derivative, preferably, essentially impermeable to liquid solvent.

The degree to which the surface is impermeable, can be measured by measuring surface adsorption, for example, in units of Cobb. ("Cobb"=g (water)/m2absorbed by the surface, which contact with water in the liquid state for 60 seconds). Adsorption of other fluids could be measured in the same way. The way of measuring adsorption units Cobb described in SCAN P12-64 TAPPI T441. The indicator surface adsorbs the t of about 20 to 30 Cobb. Suitable for use in the framework of the invention, the surface of the base layer should be the rate of adsorption of 50 Cobb or less, preferably the rate of adsorption of 30 Cobb or less, more preferably less than 20 Cobb, or most preferably of 10 Cobb or less, for example less than 5 Cobb.

Preferably, the surface of the base layer, which is applied to the starch or starch derivative has a smooth, component 200 Bendtsen or better. The way of measuring the smoothness on Bendtsen described in SCAN (Scandinavian Pulp and Paper Norms) P21-67 and in TAPPI UM535.

This required smoothness is usually achieved when the substrate is made of plastic or has a plastic surface, for example, in the case of a film of plastic or the carrier layer of paper, covered with plastic.

One reason that high barrier characteristics were not achieved according to the publication WO 97/16312 may be that the inner layer of cardboard did not possess the required degree of tightness, with an aqueous solution of starch, which was used, was able to penetrate the surface. This could have an adverse impact on several fronts. In this case, might not be smooth and continuous Powerline, drying cardboard for drying the layer of starch can cause deformation of the surface of the cardboard and, therefore, cracking of the layer of starch. These problems are eliminated when the starch is applied on a separate smooth, impermeable base layer, which is subsequently applied on the inner layer.

The cardboard used according to the publication WO 97/16312, typically would have a surface smoothness in the range of 500-600 Bendtsen. By itself it can be quite impossible to obtain a smooth and continuous layer of starch and the presence of thin areas, providing a passageway for the distribution of oxygen.

In order to avoid cracks, tears or deformations of the layer of starch or starch derivative, it is preferable that the surface on which it is applied, was smooth, for example, to the surface of the substrate had a smoothness of 200 Bendtsen or better (i.e. smaller), for example from 150 Bendtsen, more preferably about 100 Bendtsen.

Describes the materials used as carriers for starch, can also be used with other barrier materials according to the first aspect of the present invention. In General, however, the media of the plastic film is preferred when using starch, and ispolzovanie can be heated to temperatures above 100oWith drying and vulcanization.

Starch for use within the invention may be of any conventional type, however, some starches give better results than others in the used conditions. Preferred modified potato starch, such as Raisamyl 306 (Raisio), oxidized by hypochlorite. Other acceptable starches include corn starch and derivatives, such as oxypropylene corn starch, Cerestar 05773.

Derivatives of starch, are suitable for use within the invention include oxidized starch, cationic starch and oxypropylated starch.

It will be clear that when you specify that the characteristics of gas-tightness of the packaging laminated materials according to the invention are provided by a specific material, such as starch or starch derivative, this does not exclude the case when the characteristics of the gas-tightness of the resulting interaction between the specified material and the adjacent layer of the layered material, and are not the own characteristics of the specified material, taken separately.

Can be obtained auxiliary mechanism contributing to the improvement of the barrier harakteristiki of polyethylene molecules in starch and replacement of water in the starch crystals. Can be used with other polymers that produce a similar effect.

These layers of plastic can be applied to the starch or starch derivative by melt extrusion or can be applied in the form of a pre-formed film by layering by hot pressing, for example, a heated roller. In General, you can use any method that meets this preferred variant of the invention, which provides the desired modification of the barrier characteristics of the starch.

Preferably, the specified plastic layer associated with the starch or starch derivative at a temperature of at least 200oC, preferably from 250 to 350oS, more preferably from 250 to 330oC.

The invention includes a packaging container or packaging formed with the packaging laminate as described, or by the method described according to the invention.

The present invention will be further described and shown in more detail below with the aid of non-limiting examples of methods and packaging laminates obtained in a manner consistent with the preferred options for implementation of the AET method of performing the base layer coated with a barrier layer for use within the present invention; Fig. 2 schematically depicts a method for performing the laminated packaging material according to the present invention; Fig. 3 depicts a cross-sectional view of the layered packaging material corresponding to the present invention; Fig. 4 a top view in perspective known formoustoychivosti packaging container made of laminated packaging material according to the present invention; Fig. 5 (a, b, c, d) schematically depict cross-sections of four different packaging laminated materials, specific variants of carrying out the invention; and Fig. 6 (a, b, C, d) schematically depict how to perform the relevant packaging laminates shown in Fig.5.

Fig. 1 and 2 schematically depict a method that meets the present invention, selected as an example to obtain a laminated packaging material 10 shown in Fig.3. Canvas carrier layer 11, for example, of thin paper, which optionally may be covered with a layer of plastic, leaves the feed bobbin 12 and fed through the applicator 13 (ideally to a device for coating), located adjacent to the cloth by means of which, at about layer 11 in the form, essentially, the associated barrier layer 14. In the case of plastic-covered paper bearing layer dispersion or solution of the polymer is preferably applied to the side, covered in plastic. The amount of coating solution may vary, but preferably it is such that after drying, is formed entirely of a single, essentially, a continuous layer with the amount of dry matter, for example, about 0.5-20 g/m2preferably 2-10 g/m2.

When using polyvinyl alcohol bearing layer 11 preferably consists of a thin layer of paper with a number of approximately 10-35 g/m2preferably 10-25 g/m2more preferably 15-20 g/m2but can also be a plastic layer. However, thin paper has the advantage that it does not change in size with increasing temperature due to drying and possible cure that does not apply to plastic. In General, when applied polymer has to be vulcanized at temperatures above 130oWith the use of plastic film as a medium is not recommended.

The barrier layer 14 is applied on the carrier layer 11 in the form of an aqueous polymer dispersion or polymer solution that includes a polymer with such ha the er polymer with functional hydroxyl groups, for example, polyvinyl alcohol, ethylene vinyl alcohol, starch, starch derivative, carboxymethyl cellulose and other cellulose derivatives, or mixtures thereof.

The barrier layer 14 may also include a hydrophobic polymer, as described in the publication WO 97/22536, for example, a copolymer of styrene and butadiene.

The barrier layer 14 can also include a polymer having functional groups that react with functional hydroxyl groups of the above polymer to obtain a crosslinked barrier layer 14. Such polymers can be polyolefins, modified carboxylic acid groups, or grafted copolymers with monomers containing carboxylic acid group in the olefin Homo - or copolymer. Alternatively, such polymers can be arbitrarily selected copolymers of olefinic monomers and monomers containing functional groups are carboxylic acids, such as carboxylic acids, anhydrides of carboxylic acids, metal salts of carboxylic acids or their derivatives. Specific examples of suitable functional polyolefins include Homo - or copolymers of polyethylene and polypropylene grafted maleic anhydride, ethylenically acid or ethylene layer 14 consisted of a mixture of polyvinyl alcohol and a copolymer of ethylene and acrylic acid. The ratio of concentrations in a mixture of polyvinyl alcohol and a copolymer of ethylene and acrylic acid in the barrier layer 14 should be such that polyvinyl alcohol can form a surface protection against penetration of natural gas in the packaging laminate, the number of a copolymer of ethylene and acrylic acid should be sufficient for the formation of the associated phase, which partially protects the alcohol and partially effectively counteracts or prevents the penetration of liquid through the barrier layer 14.

Canvas carrier layer 11 is served after coating after drying device 15, for example a drying using infrared radiation or the dryer using hot air, which acts on the coated side of the base layer 11 to remove water and drying and curing the applied barrier layer 14 at a temperature drying, which constitutes approximately 80-100oWith, preferably about 90-95oAnd, when it is applied at curing temperature for the crosslinking of functional groups included in the deposited polymer mixture, i.e. the temperature to 190oWith, preferably 170oC.

Finally, the completed base layer 11 with Nanase the th process of making laminated material for the manufacture of laminated packaging material 10, with improved barrier characteristics.

Supporting layer 11 coated with a barrier layer 14 can ideally be used for the production of the packaging material 10 in an appropriate manner and using the appropriate production equipment, as the production of the packaging material with aluminum foil as a barrier layer. In Fig.2 shows a painting of a rigid configuration, but flexible inner layer with a number of approximately 100-500 g/m2preferably about 200-300 g/m2that may be normal fibrous layer of paper or cardboard, having a suitable packing qualities. The inner layer 16 is carried out through the gap between two rotating rollers 17 and connects with the canvas carrier layer 11 with dried or vulcanised barrier layer 14 when applying - using the extruder 18 is one or more layers spriteimage thermoplastic 19, preferably of polyethylene, between the inner layer 16 and the carrier layer 11. As shown, the barrier material 14 is located on the outer surface of the base layer, but, alternatively, it can be located on the inner surface.

Thus, Lamin is of thin layers 21, 22 spriteimage thermoplastic, preferably polyethylene, on both outer sides of the fabric using extruders 23, with the completed laminated packaging material 10 corresponding to the present invention acquires the structure cross-section, schematically shown in Fig.3. Alternatively, two of the extruder 23 can be placed in series for sequential extrusion of thin layers 21 and 22 of thermoplastic on the respective outer side of the laminated cloth.

Two layers 21 and 22 plastic fulfill their role: on the one hand protect the packaging material 10 from moisture and damp outside and also give packing material the ability to be sealed conventional, so-called, by way of thermocline, due to which facing each other layers of plastic may be joined together by applying heat and pressure by means of surface alloying. The operation of thermocline provides obtain mechanically strong, impermeable to fluid sealing connection with the conversion of the packaging material in the finished packing containers.

The outer plastic layer 22, which is printed on the packaging material 10 on toget be supplied with the necessary printed images of decorative and/or informational properties to identify the packaging of the product.

Made of laminated packaging material corresponding to the present invention, may be made impervious to liquids, formoustojchivy packing 24, with enhanced characteristics for gas-tightness, using known packaging and filling devices, which in the course of the continuous form, fill and seal material, forming a complete package 50. An example of such a known packaging container 50 shown in Fig.4.

First, the longitudinal edges of the laminated packaging material 10 are mixed and the tube filled with the appropriate information, then separate package 50 are separated from the fabric repetitive transverse sealing of the tube below the level of content. Packaging 50 are separated from each other by performing incisions in the transverse areas of compaction and form the desired geometric configuration, usually in the form of a parallelepiped, through the final forming operations of folding and sealing.

It should be noted that different packaging laminates corresponding to the invention, can contain many layers in addition to the layers shown in the drawing that the description of the shown embodiments of the invention should not be construed as limiting the present invention.

In Fig.5A schematically shows a cross section of a packaging laminate according to a simple variant of the invention, under the General position 10A, whereas Fig.6A schematically shows the method (indicated by the position 20A) receiving the base layer with the structure used in the laminate material 10A. Laminate 10A contains supporting layer 11, the surface of which has a smooth, essentially, not absorbing structure. Supporting layer 11 may be a plastic film or a thin paper having a specified surface quality. The substrate of the thin paper of about 10-25 g/m2not able to absorb a lot of the starch solution, because it's very thin, and as such available on the market thin paper usually have a very smooth and glossy, hard surface. Particularly suitable for this purpose, the paper is the so-called glassine, which is, however, quite expensive compared to other available in the market securities. Fit can be paper, MG Kraft paper (Munksjo) 10-25 g/m2where MG denotes that the paper is smooth on one surface, on which, preferably, will be applied starch. Most preferably, the substrate 11 was plastro solution or dispersion of starch is applied on the upper side of the sheet substrate 11, which moves in the direction shown by the arrow, with the feed reel (not shown) in paragraph 13A of the coating. The starch solution, preferably, is applied using a technique for applying a liquid film, also called "dispersion coating or wet coating", which is well known in the prior art application of aqueous solutions and dispersions, however, other methods of coating are also suitable according to the invention, for example, application of a coating. An aqueous solution of starch is applied in an amount such that the applied and dried, the layer 14 of starch had the weight to the thickness or the surface of from about 0.5 to about 3 g/m2.

The canvas is covered with a water solution, is served later in the paragraph 15A drying, in which the fabric is dried by a drying device for removing water from an aqueous solution of starch. Drying can be performed by any known drying device, such as drying using infrared radiation or air dryer. Preferably, drying is carried out at a temperature of about 80-100oC.

From the point of drying the dried cloth, with the top layer 14 of starch, served later in the paragraph 23a extrusion, awns on the layer of plastic perform through surface alloying layer of plastic and a layer 12 of starch, receive simultaneous application of heat and plastic. Preferably, the molten polymer is extruded onto the dried layer of starch simultaneously with the filing of the fabric through the gap between two rotating cooling rollers 24A, thus formed laminated material having three of the top layer of the packaging laminate 10a, shown in cross section in Fig.1A, with the outer layer 21 of plastic material deposited on the layer 14 of starch. Extruded plastic material is preferably a thermoplastic polymer, preferably polyethylene, and most preferably low density polyethylene, which provides efficient conversion of the packaging laminate 10 is impervious to liquids, formoustojchivy packing by means of the so-called thermocline. The temperature during extrusion should be at least 200oC, preferably from about 250oWith up to about 330oC.

In an alternative embodiment, the specified surface fusion between the layer 14 of starch and a layer 21 of the plastic can be obtained by applying a pre-made film from a thermoplastic to a dried layer 14 of starch by odnovremennoi film together through the gap between the hot platens, the temperature transmitted from the hot platens, is at least 200oWith and up to 350oC, preferably from about 250oWith up to about 330oC.

Thus obtained three layers of material may then be applied to the cardboard inner layer 16, as shown in Fig.2, to receive a packing laminate 10A.

In Fig. 5b schematically shows a cross section of a packaging laminate 10b corresponding to another variant of the invention, and Fig.6b schematically shows the method (indicated by the number 20b) obtain a laminate 10b.

According to this variant embodiment of the invention, the substrate or supporting layer 11 is covered on both sides with an aqueous solution of starch as described in the embodiment of the invention shown in Fig.5A and 6A.

Therefore, a laminate 10b, which are obtained by the process shown in Fig.6b, includes a substrate 11, as described above, preferably, the film of plastic material, a thin layer (14, 14') of starch deposited on each side of the substrate 11, and the outer layers (21, 21') of the plastic deposited on the outer side of the respective layers of starch by surface fusion of the outer place structure could be obtained the effect of double barrier for gas, because these two are related by fusing the boundaries between starch and plastic.

Accordingly, according to the method shown in Fig.6b, a thin layer of an aqueous solution of starch is applied on each side of the sheet substrate 11, which is fed in the direction shown by the arrow, from a feed reel (not shown) in paragraph 13b coating. The starch solution, preferably applied using a technology dispersion coating in such amount on each side of the substrate 11, so that each applied and dried layer 14, 14' of the starch had the weight to the thickness or the surface of from about 0.5 to about 3 g/m2.

The canvas is covered with a water solution, is held forth in paragraph 15b drying where the cloth is dried by a drying device for removing water from the deposited layers of an aqueous solution of starch. Preferably, drying is carried out at a temperature of about 80-100oSince, as described above.

From the point of drying the dried fabric with the upper layer 14 and lower layer 14' of the starch is fed further through the bending roller 25 in paragraph 23b of the extrusion where the cloth is additionally covered with a layer of plastic on each side. Thus, the layers 21, 21' plastic naimer is extruded on the dried layers of starch simultaneously with carrying out the fabric through the gap between two rotating cooling rollers 24b, in principle, as described above, thus forming the layered material 10b shown in cross section in Fig.5b. Laminate 10b may be connected with the internal layer for the formation of the completed packing element, as shown in Fig.2.

In Fig.5C schematically shows a cross section of a packaging laminate 10C corresponding to the alternative embodiment of the invention, while Fig.6C schematically shows the method (indicated by the number 20C) production of laminated material 10C.

Paper or cardboard inner layer for use in the invention usually has a thickness of from about 100 microns to about 400 microns and a surface weight of approximately 100-500 g/m2preferably about 200-300 g/m2.

According to the method 20s the first web of the inner layer 16 is fed in the direction shown by the arrow, from a feed reel (not shown) in paragraph 28 of the extrusion coating, in which the second fabric base layer 11 having a dried layer 14, 14' of the starch deposited on each side, is applied over the inner layer by means of the intermediate molten spriteimage layer 19 of thermoplastic polymer, predpochtitelno inner layer, starch and substrate is then fed in paragraph 29 of the extrusion, in which the outer layer of thermoplastic 21, 22, preferably, such as low density polyethylene, optionally extruded on each side of the layered material 16' so that the layer of starch on the outside of the substrate 11, which is the opposite side, deposited on the inner layer and the opposite side of the inner layer 16, both were covered with the extruded thermoplastic through the formation of layers 21 and 22.

Suitable thermoplastic resins for the outer layer 14 are polyolefins, preferably polyethylene, and most preferably low density polyethylene, such as, for example, low density polyethylene, linear low-density polyethylene or metallocene polyethylene is obtained in the presence of monospitovo catalyst. The outer layer 22, which in the end will form the outer side of the packaging container obtained from the packaging laminate may, alternatively, be applied to the fabric 16 of the inner layer during the operation, prior to the operations of applying and drying the starch.

In Fig. 5d schematically shows a cross section of a packaging laminate FDS (indicated by the number 20d) obtain a laminate 10d. The packaging laminated material 10d is produced by applying and drying a thin layer 12 of an aqueous solution of starch on the upper side of the substrate 11, which presents a plastic film as described above, according to the method 20A, during the initial operation.

According to the method 20d, the first leaf of the inner layer 16 is fed in the direction shown by the arrow, from a feed reel (not shown) in paragraph 28' extrusion, in which the fabric 11 of the substrate having the dried layer 14 of starch deposited on one side, is applied so that the layer 14 of starch converted to the inner layer, and is applied to the inner layer by means of the intermediate molten spriteimage layer of thermoplastic polymer, preferably polyethylene, and most preferably low density polyethylene. The substrate 11, that is, a plastic film, may form the outer layer of the packaging laminate, facing the inside of the packaging container made of it, thus forming the inner layer of the container. In the final paragraph 29' extruding the outer layer 17 of thermoplastic is applied by extrusion.

The problem with layered materials described in the publication WO 97/16312, with the attendance for the production of cardboard laminates with aluminum foil as a barrier for gas. Such packaging laminates performed by connecting the substrate layers of cardboard and barrier foil using spriteimage polyethylene. In contrast, as can be seen from the above, the base layer of plastic or thin paper carrying a coating of starch on one or both surfaces with plastic, already printed on one or both layers of starch or without it, can serve as a simple replacement of the aluminum foil using known equipment with minimal setups. Preparation of the carrier material, the carrier starch, can be done entirely separately, on different hardware, if necessary, with existing packaging line at the factory can easily adapt to use new materials.

Thus, an additional important advantage of the illustrated preferred variant of the method is that the operation of applying and drying the starch solution can be performed off-line processing of layered material that allows you to avoid costly modifications and overhaul of equipment for manufacturing packaging laminate having inner layer. By applying the SL is actually not absorbing surface, for subsequent connection to other layers of plastic and an inner layer of the operation of the coating can be performed using the same equipment and methods that are currently in use when applied, for example, aluminum foil and inner layers.

From blanks of the packaging laminate 10 in the form of a sheet or fabric, preferably with a pre-made lines, curves and color decorative print is produced formoustojchivy packaging disposable in accordance with known technology "forming-filling-sealing, whereby the packaging form fill and seal using modern, sustainable packaging and filling devices. From, for example, canvases layered packaging material such packages are produced so that the canvas is first converted into the pipe through the connection of the two longitudinal edges of termocline obtaining longitudinal sealed lap joints. The tube is filled with content, such as a liquid food product, and is divided into individual packages by repeated transverse sealings of the tube transversely to the longitudinal axis of the pipe, below the level the seals and give them an unusual geometric shape, usually the shape of a parallelepiped, with additional operations formation and thermocline by known methods.

Through the use of the above described methods and materials by coating an aqueous solution of starch or its derivative on a substrate to support a layer of starch, which consists of specially selected material, in combination with subsequent drying and coating the layer of plastic by heat melting the surface of the plastics obtained significantly improved performance packaging laminated materials in kislotonepronitsaemost compared with the characteristics according to the publication WO 97/16312. Received a radical improvement of the characteristics of the gas-tightness of the applied layer of starch, which is increased by a factor of nearly 10, to obtain the so-called high-performance barrier layer. The best results for gas-tightness is obtained when the supporting layer consists of a polymer or a surface coated with the polymer, however, the layer of thin paper having a surface weight of approximately 10-25 g/m2with a smooth, essentially, not absorbing surfaces, will also provide improved performance on the lawn is up>2put on a plastic film (polyester) and then coated by extrusion with a layer of low density polyethylene, get kislotonepronitsaemost, component 9 cm3/m224 hours at a pressure of 1 ATM (23oC and 50% relative humidity). Similarly, the layer of starch 5 g/m2gives kislotonepronitsaemost constituting about 4 cm3/m2and 7 g/m2give only 3 cm3/m2.

Optimal characteristics for gas-tightness obtained in these examples were used carrying a layer of plastic or with the surface of the plastic, thus, at least in part, are the result of the quality of surface smoothness and moisture-repelling abilities. While the mechanism of the effect obtained when using linked by fusing the boundaries between layers of starch and plastics are not fully understood, it can be assumed that the optimum characteristics for gas-tightness can be partially the result of such boundaries, formed on both sides of the layer of starch as the substrate layer, which is applied to the starch, is a layer of plastic, and the phenomenon of the same type may occur in this gra is meniu mainly applied in an amount of from 0.5 to 3 g/m2dry matter. In quantities less than 0.5 g/m2the tolerances on the thickness of the layer, and the characteristics of permanence becomes less reliable. On the other hand, when amounts greater than about 3 g/m2the risk that the gas-tight layer of starch can become brittle and inflexible, will increase. However, the number of the applied dry matter up to 5 g/m2possible, and for some types of packages and applications can be valid even large number. Characteristics of a layer of starch on the permanence, in General, increase with increasing thickness. Optimal and preferred the applied amount of starch ranges from about 1.5 to about 2 g/m2.

Examples of Packaging laminates were prepared using the inner layer of cardboard Billerud Duplex bearing 12 g/m2low density polyethylene on the outside.

They were prepared by extrusion of low density polyethylene at a temperature of 325oWith the cardboard "Duplex" (Billerud), with a surface weight of 280 g/m2and bending strength/stiffness to bending 320 mn. Was applied to low density polyethylene brand LD273 (Dow) having a melt index of 6.5 to 7.5.

oC.

There were prepared various combinations of carrier material and barrier material, as shown in detail in the table, and everyone was laid on the inner side of the cardboard inner layer by extrusion between them a layer of 10-15 g/m2low density polyethylene at a temperature of 325oC. When preparing element of the barrier material and the supporting material starch for coating was prepared from a dry powdered starch by mixing 10 weight. % starch with water at ambient temperature to form a suspension. The suspension was heated under stirring up to 90-95oC and was maintained at this temperature for 30 minutes. When heated, the starch is swollen.

If it is possible, for example, in the case of oxidized starch Raisamyl 306 (Raisio), starch before using as the coating was cooled to ambient temperature. However, when this may lead to conversion of starch in the gel, for example, in the case of oxypropylated starch, CERESTAR, the starch must be heated (60oC).

Starch weight in the wet state, which is approximately 10 times more necessary the shadow wet-dispersed film type "knife over roll", supplied Harada, also known as "comma-direct coater" or "bull-nose coater".

To accelerate drying of starch was carried out the first operation of drying using heat infrared radiation to a temperature of 80-100oWith, followed by the operation of the hot air drying, during which the coating of the starch was dried with hot air at a feed rate of the sheet is 1 m/min At a temperature of 110oC. generally suitable temperature from 100 to 130oWith, depending on the feed speed on the line.

In some cases, the dried layer of starch was coated by extrusion of low density polyethylene (LDPE). About 25 g/m2low density polyethylene was applied by way of extrusion on the dried layer of starch in the feed speed of 200 m/min, a temperature of 325oC and the temperature of the cooling roller 10-15oSince, as described above. The distance between the extrusion head and the cloth was usually 10-30 see Spritely low-density polyethylene was in contact with the canvas just before entering into the gap between the cooling roller and pressure roller.

A layer of polyvinyl alcohol/ethylenically acid was applied in aqueous solution and dried at a temperature of 150o

Specialist in the art will understand that the present invention is not limited to the illustrated variant of its implementation and that various modifications and changes may be made without departing from the scope of the inventive idea defined by the attached claims. For example, the structure of the packaging material, of course, not limited to the shown number of layers and the number can be as big and smaller, and can freely be varied depending on the desired field of use of the packaging material.

Claims

1. A method of obtaining a laminated packaging material comprising the inner layer of paper or cardboard and the barrier layer deposited on one side of the inner layer, characterized in that the polymer dispersion or polymer solution is applied as a barrier layer on at least one side of the base layer and dried by heating for removing water, after which the bearing layer is coated with the dried barrier layer Combi is ferny layer is applied by coating a liquid film of an aqueous dispersion or solution of the polymer.

3. The method according to p. 1 or 2, characterized in that the aqueous dispersion of a polymer or a polymer solution, which is applied as a barrier layer that includes a polymer with hydroxyl functional groups.

4. The method according to p. 3, characterized in that the polymer with a hydroxyl functional groups selected from polyvinyl alcohol, ethylene vinyl alcohol, starch, starch derivatives, carboxymethyl cellulose and other cellulose derivatives, or a mixture of two or more of them.

5. The method according to any of paragraphs. 1-4, characterized in that the aqueous dispersion of the polymer or the polymer solution deposited as a barrier layer, dried and, if necessary, vulcanizer at a temperature of approximately 80-230oC.

6. The method according to any of paragraphs. 1-4, characterized in that the aqueous dispersion of the polymer or the polymer solution deposited as a barrier layer, dried at 140-160oAnd vulcanizer at a temperature of from 170 to 230oC.

7. The method according to any of paragraphs. 1-6, characterized in that the aqueous dispersion of the polymer or the polymer solution deposited as a barrier layer that includes a polymer with functional groups carboxylic acid.

8. The method according to p. 7, characterized in that the polymer with functional krylovii acid or mixtures thereof.

9. The method according to p. 8, wherein the barrier layer consists of a mixture of polyvinyl alcohol and a copolymer of ethylene and acrylic acid.

10. The method according to any of paragraphs. 7-9, characterized in that the dried barrier layer vulcanizer at temperatures up to 190oC.

11. The method according to any of paragraphs. 1-10, characterized in that the barrier layer is applied on the carrier layer in the amount of about 0.5-20 g/m2preferably 2-10 g/m2.

12. The method according to any of paragraphs. 1-11, characterized in that the carrier layer consists of paper or plastic.

13. The method according to any of paragraphs. 1-12, characterized in that the carrier layer preferably consists of paper in the amount of approximately 15-35 g/m2.

14. The method according to any of paragraphs. 1-13, characterized in that the carrier layer carrying at least one barrier layer, combine and connect with the inner layer by extrusion have between them a layer of thermoplastic.

15. The method according to p. 14, characterized in that the carrier layer carries the barrier layer on one side and is combined with the inner layer by extrusion of a layer of thermoplastic located between the carrier layer and inner layer.

16. The method according to p. 15, characterized in that the outer layer base layer carries the barrier layer on one or both sides and is combined with the inner layer by extrusion of a layer of thermoplastic, located between the inner layer and barrier layer.

18. The method according to p. 17, characterized in that the carrier layer carries a barrier layer on its both sides and a layer of thermoplastic is applied on the outer layer of barrier material by extrusion.

19. The method according to any of paragraphs. 1-18, characterized in that the layer of plastic is applied between the inner layer and the carrier layer or the barrier layer includes a substance acting as a barrier to light.

20. Layered packaging material, characterized in that it is obtained by the method according to any of paragraphs. 1-19.

21. The packaging laminated material having a paper or cardboard inner layer and at least one gas-tight layer of starch or starch derivative, providing characteristics kislotonepronitsaemost of 50 cm3/m2for 24 h at a pressure of 1 ATM at 23oC and a relative humidity of 50% or less, and the specified gas-tight layer has a dry weight of coating or coating weight in the aggregate state is not more than 7 g/m2.

22. The packaging laminate according to p. 21, wherein the characteristic of kislotonepronitsaemost, provide gas-tight layer cromalino humidity of 50% or less.

23. The packaging laminated material under item 21 or 22, characterized in that it contains a layer of plastic, which directly caused the gastight layer.

24. The packaging laminated material under item 23, wherein the plastic is polyethylene, or polypropylene, or polyethylene terephthalate.

25. The packaging laminate according to any one of paragraphs. 21-24, characterized in that the gas-tight layer is applied in an amount of 5 g/m2covering of dry matter.

26. The packaging laminate according to p. 25, characterized in that the gas-tight layer is applied in the amount of 0.5-4 g/m2covering of dry matter.

27. The packaging laminate according to p. 25, characterized in that the gas-tight layer is applied in the amount of 0.5-3 g/m2covering of dry matter.

28. The packaging laminate according to p. 25, characterized in that the gas-tight layer is applied in a quantity of 1.5-2 g/m2covering of dry matter.

29. The packaging laminate according to any one of paragraphs. 21-28, wherein the gastight layer additionally contains a small amount of polyvinyl alcohol, or ethylenically acid, or mixtures thereof.

30. The packing container is great for the Orme sheet or cloth.

31. The packing container, characterized in that it is made by forming a bending of laminated packaging material according to any one of paragraphs. 21-29 in the form of a sheet or cloth.

Priority items:
10.03.1998 - PP. 1-4, 7-12, 14 to 20 and 30;
13.05.1998 - PP. 21-29, 31;
09.03.1999 (PCT/EP 99/01495) - PP. 5, 6 and 13.

 

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SUBSTANCE: packaging material 10 has central layer 11 of paper or cardboard and layer 12 of polyolefin with mineral filler on one side of central layer. Layer 12 with mineral filler has thickness of from 30 micron to 100 micron and has mineral particles in an amount of from 40% to 70% by weight of layer 12 with mineral filler. Both sides of central layer are provided with water-impermeable coating of polyolefin.

EFFECT: increased rigidity and provision for manufacture of containers with improved capturing properties.

8 cl, 4 dwg

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