The laminated packaging material, a method of manufacturing a laminated material and a packaging container produced from it
The invention relates to a laminated packaging material comprising the inner layer of paper or cardboard and gazoballonnyj layer of the polyamide mixture comprising the condensation polymer methoxyaniline and adipic acid, and the second crystalline or semi-crystalline polyamide, printed on one side of the inner layer by covering the joint extrusion. The invention also relates to a method of manufacturing the laminated packaging material and a packaging container produced from the laminated packaging material. 3 S. and 11 C.p. f-crystals, 5 tab., 3 Il. The present invention relates to a laminated packaging material comprising the inner layer of paper or cardboard and gazoballonnyj layer of a polyamide, comprising the condensation polymer methoxyaniline and adipic acid (Nylon-MXD6), printed on one side of the inner layer together with at least one layer thermovalve plastics, by covering the joint extrusion.The present invention also relates to a method of manufacturing the laminated packaging material according to the invention, as well as the packaging container, proiso know the use of the laminated packaging material disposable nature for packaging and transportation of liquid food products. Typically, these laminated packaging materials consist of a rigid form, but the folding of the inner layer consisting, for example, of paper or paperboard, to achieve the high mechanical rigidity of the form. Impervious to liquid coating of plastic applied on both sides of the inner layer and effectively protect the inner layer from absorbing the liquid fibers from moisture. These outer layers are usually composed of a thermoplastic, preferably polyethylene, which, in addition, improves the sealing properties of the packaging material to the packaging material can be turned into a finished package with the given geometry.However, the laminated packaging material consisting only of paper or cardboard and is impervious to liquid plastic, not enough density properties against gases, in particular gaseous oxygen. This is a major flaw in the packaging of many foods, shelf-life, taste and nutrient content which is rapidly deteriorating in contact with gaseous oxygen. Examples of such food products are fruit juices, vitamin C content in which snigees the crystals barrier to gases, in particular gaseous oxygen, a layer having good properties for the delay gaseous oxygen, for example, aluminum foil ("Alifoil"), EVOH (ethylene vinyl alcohol) or PVOH (polyvinyl alcohol), on the other side of the inner layer, which is intended for the treatment of the inside of the finished package.In General, preferably the production of packaging containers for the so-called "extended storage life on the shelf" (ESL) when stored refrigerated, that is, to maintain the vitamin-C content and quality of the Packed product over about 6 weeks of storage at a temperature of 8oWith about 8 weeks of storage at 7oAnd about 10 weeks of storage at 4oC.However, the known hashbarger have certain disadvantages. For example, in some cases, from the point of view of cost, environment and waste, it was assumed that it is possible to replace the aluminum foil used as gatbering material in food packaging. Barrier polymer such as EVOH and PVOH, respectively, are very sensitive to moisture and quickly lose their barrier properties against oxygen gas, when exposed to moisture environment. This, among other things, the which is impervious to moisture. Alternatively EVOH and PVOH, respectively, can be combined with one or more known, approved for food applications polymers for the formation of a continuous, well-integrated layers of high getbasename properties, which are also stored in a wet environment. However, the production of packaging materials, including gaseous layers of EVOH and PVOH, respectively, leads to an increase in cost and material and production of the desired multi-layer laminate, such as gazoballonnyj layers must be surrounded by at least one, often two protective outer layers of plastic on each respective side of the laminate.U.S. patent 4777088 discloses a packaging laminate for the production of packaging for juice, consisting of an inner layer of paper or cardboard with gazoballonnym layer which is applied thereto and includes a nylon (not disclosed in detail), and layer ionomer binder, namely Surlynprinted on gazoballonnyj layer as an intermediate binder layer with the internal (inside the package) polyolefin layer.EP 0520767 discloses a packaging laminate, sostojatsja DuPont Corp, USA), and a binder layer applied between them.The main disadvantage of these known packaging laminate is, however, that they do not have good enough getbasename properties for ESL package at an economical thickness of the polymer layer.Condensation polyamide polymer from methoxyaniline and adipic acid, called "Nylon-MXD6", is a semi-crystalline polyamide and has special properties in comparison with other conventional polyamides, such as, for example, high tensile strength, bending strength and modulus of elasticity, a higher glass transition temperature, low water absorption and good gazoballonnyj properties, against, for example, gaseous oxygen.U.S. patent 5164267 (withdrawn) describes a laminated composite consisting of a sheet of substrate on the basis of celluloide material, the laminated multilayer film containing at least one layer based on a polyamide obtained by polycondensation of aliphatic dicarboxylic acids with Xylenediamine, for example, Nylon-MXD6, while multi-layer film caused by joint extrusion on a substrate with a polyolefin layer in contact with the substrate.
inutah of paper or paperboard for liquid food products, because this material forms a fragile layer that splits easily, for example, when forming or bending of the packaging material, and therefore provides a poor barrier to gases and liquids. In addition, Nylon-MXD6 in gazobetona layer also has an adverse effect on the sealing properties in the process of sealing the packaging material in a packaging container, which leads to packages having a low tightness.JP-A-06305086 describes a laminate of polyamide film biaxial drawing and paper layer, in which the polyamide film contains at least two polyamide layer, and at least one of the layers contains Nylon-MXD6. Film biaxial extrusion laminated to the paper layer by means of dry lamination using adhesives, or by lamination by extrusion. Such film biaxial drawing, therefore, previously produced by various processes, such as, for example, blown film, and then laminated to the other layers.The obtained laminate in JP-A-06305086 quite different from the laminate under item 1 of the formula of the present invention. To promote adhesion between the paper layer and polyamide layer should be used advisatory in turn requires more and/or different materials in the laminate, and thus, leads to increased production costs and a greater detrimental effect on the environment both from the point of view of working conditions, and environmental conditions. In addition, the adhesion between the paper layer and the polyamide layer is likely to deteriorate in such a laminate, since the surface of pre-produced film will be oxidized and/or cured and will not easily stick to the extruded binder layer. In particular, the method is more complicated and less economical to produce such a laminate, as it requires additional pre-production film biaxial drawing.Brief description of the invention Therefore, the present invention is to provide a new, cost-effective, environmentally friendly and well-integrated laminated packaging material of the type described in the introduction possessing good getbasename properties, in particular against gaseous oxygen, as well as good barrier properties against liquids, and good mechanical properties such as flexibility and adhesive strength between the layers.An additional object of the present invention consists in thedat for storage of fruit juices with increased storage life on the shelf, for about 6-10 weeks when stored refrigerated.These objectives are achieved according to the present invention through the laminated packaging material comprising the inner layer of paper or cardboard and gazoballonnyj layer of a polyamide, comprising the condensation polymer methoxyaniline and adipic acid (Nylon-MXD6), printed on one side of the inner layer together with at least one layer thermovalve plastics, by covering the joint extrusion, in which gazoballonnyj layer also includes a second crystalline or semi-crystalline polyamide.By mixing Nylon-MXD6 with other crystalline or semi-crystalline polyamide, such as PA-6 or PA-6/66, properties can be adjusted, it is possible to obtain improved elongation at break and improved sealing properties. The elongation at break of Nylon-MXD6 is only about 2.3%, while for the standard RA-6 it is usually 400-600%. However, too high content of RA-6 will lead to bad gas properties, because they decrease exponentially relative to the number of PA-6. Examples used polyamides in this context are polyamide-6 ( polyamide is an immiscible composition, that is, a two-phase mixture, for which the DSC measurement shows two separate point or melting interval, that is, shows two melting peak, instead of just one with Nylon-MXD6 as a matrix. Such immiscible compositions have the advantage of further improved coloradobrianna properties, as well as improved tensile strength.To achieve optimum properties in respect gazoballonnyj properties, mechanical properties, durability, sealing and resistance to the formation of a swelling number of Nylon-MXD6, included in the mixture in gazobetona layer according to the present invention, comprises more than 50 weight. % and less than 100 weight. %, preferably 60-90 weight. % and more preferably 70 to 80 weight. %.According to one preferred variant implementation of the invention, the second polyamide is a "malono-ceramic hybrid (NCH), which is a molecular composite consisting of crystalline polyamide, such as PA-6, PA-66, PA-6/66 or RA-12, as well as evenly distributed silicate layers. NCH is formed in the polymerization process by dispersion of ceramic mineral in the monomer and polymerization, which creates the morphology of very small, well disperse the output and excellent mechanical properties. Such polyamides are described, for example, in "Journal of Applied Polymer Science", Vol.49, 1259-1264 (1993), and Vol. 55, 119-123 (1995). The advantage of the RA-6 is its low cost, whereas NCH based on PA-6, PA-66 or PA-6/66 has the advantage that gives the best gazoballonnyj properties than its corresponding base polymers. In addition, NCH is the best barrier for moisture than pure RA-6, better than about two times. Example NCH suitable for the mixtures according to the present invention, based on PA-6 and commercially available from UBE Industries (Grade 1022 CM1).Through this blending of Nylon-MXD6 with NCH based on, for example, RA-6, receive optimal gazoballonnyj properties, and mechanical properties. The ratio of Nylon-MXD6 (which is relatively expensive) can be reduced without deterioration gazoballonnyj properties to the same value, as in the case of use of pure PA-6. At the same time, you will receive a mixture of substantially greater elongation at break and, thus, more resistant to cracking when forming and bending, providing uniform gas-tight barrier layer. A mixture of 75 wt.% Nylon-MXD6 and 25 wt.% NCH-PA6 has an elongation at break of more than 200%.In addition, when using NCH as the second component of the mixture of Nylon-MXD6 sijaitsevalta outward from the vertical plane between the corners of the package. Increased resistance to swelling when using NCH, perhaps partly a consequence of the stiffness properties of the NCH material. The modulus of elasticity NCH-PA6 is, for example, about 830-880, whereas for RA-6 it is only 580-600 N/mm2. In addition, flavobacteria properties NCH approximately two times better properties of PA-6. It is very important to reduce the swelling effect, as buyers in some countries discriminate against vsdata appearance packing containers, thinking that distended appearance appears due to fermentation, etc. food.According to the second preferred variant implementation of the present invention provides even more ekonomichnyi environmentally friendly packaging laminate, which improved gazoballonnyj properties, at the same time may be provided as a packaging laminate, better adapted for the production of packaging containers having improved seal. These tasks are achieved with the use of polyamide gatbering layer by covering the joint extrusion, directly on the inner layer of paper or cardboard without intermediate adhesive or binder polymer layer. In affect, and the view of natural sources, re-use, and cost. The expression "extruded floor" thus implies both the extrusion and applying a layer of extruded plastics on the substrate, which is different from the so-called "extrusion-lamination", that is, the lamination of pre-produced film on a substrate by extrusion of the binder of the intermediate layer between the substrate layer and the layer of pre-produced film. It was shown that gazoballonnyj properties of a laminate having a three-layer structure with gazoballonnym layer of a mixture of Nylon-MXD6, a binder layer and polyolefin layer covering the inner side of the inner layer by co-extrusion, improved compared to a laminate having a five-layer structure with additional polyolefin layer in contact with a cardboard layer and a binder layer between the polyolefin layer and gazoballonnym layer.In addition, when the joint extrusion of three-layer structure at one stage, the outer polyolefin layer of the three layers can ekstrudirovaniya at a lower temperature than when the joint extrusion of the double-wall structure having two outer polyolefin layer on the cardboard. is the usual case (it is desirable to include in the process as little as possible extruders), you must ekstradiroval two outer layers at the same temperature. To promote adhesion between the layer of LDPE and cardboard preferred temperature is about 320oC. However, for the outer layer of LDPE laminate can be ekstradiroval at lower temperatures (280oC) LDPE, extrudable at such low temperatures, less prone to oxidation and is more suitable for subsequent heat sealing in the process of transformation of the packaging laminate in a paper container. The risk of getting the "plastic" taste of the Packed product will be excluded if the polyethylene ekstragiruyut at lower temperatures. In the five-layer structure, the temperature of the extrusion somewhere between should be chosen as a compromise to balance adhesion to cardboard against termosvarivaemaya outer LDPE layer, since the two LDPE layer come from a single extruder.It has been proven that gazoballonnyj layer containing a mixture of Nylon-MXD6 and RA-6 or NCH, well glued to the inner layer of paper or paperboard in such high linear velocities, which are necessary for the production of economical laminates. It is not always obvious, because in this respect, various polyamides have different properties. RA-ewout, that plastic layer is glued to the cardboard with a strength greater than the cohesion in the cardboard. Thus, the gap that appears when testing on a break occurs in a cardboard layer, but not between layers. This can be seen when the surface is "broken" plastic cover layer of paper fibers. Similarly, layers NCH or a mixture of PA-6 and NCH is not glued to the cardboard, while the Nylon-MXD6 somewhat stuck. However, the relationship between Nylon-MXD6 and paper can easily be destroyed, because the layer of Nylon-MXD6 is brittle and not flexible and will crack and flake off from the cardboard, when the laminate is bent or twisted.Compared with lamination gatbering layer on the inner layer with an intermediate layer of polyethylene, it has also been proven that the application gatbering layer directly on the inner layer leads to improved barrier to gaseous oxygen by approximately 30-40%. This may be due to the equilibration of moisture between the inner layer and gazoballonnym layer by direct application. When gazoballonnyj layer is in direct contact with the paper or cardboard layer, the result will be such that the moisture from adhesibility layer. The result is a lower moisture content will remain in the polyamide layer, resulting gazoballonnyj properties are better kept in gazobetona layer in this particular case.This unexpected increase coloradobrianna properties does not cover all of the polyamides. This is true only for Nylon-MXD6 and possibly due to the fact that gazoballonnyj properties of Nylon-MXD6 reduced at relatively high humidity, as is usually the case when packaging liquid food products.Gazoballonnyj layer can of course be applied to any desired thickness, but according to a preferred variant implementation of the invention, which is particularly suitable for packaging containers for fruit juices with increased storage life on the shelf, gazoballonnyj layer deposited on the inner layer in the amount of approximately 3-30 g/m2more preferably 4-12 g/m2and more preferably 5-8 g/m2. The reason for this is that when the amounts of deposition of below 5 g/m2can cause a lot of instability in the process for applying and barrier properties. When the amounts of deposition of about 8 g/m2the packaging laminate becomes less economical.Worn polyolefin layer, attached to getbasename layer via a layer of adhesive polymer applied between gazoballonnym layer and the polyolefin layer. The polyolefin layer may contain various types of polyolefins, for example polyethylene, ultra low density (ULDPE), low density polyethylene (LDPE), linear density polyethylene (LLDPE) and metallocene polyethylene (m-PE), or mixtures thereof. In particular, m-RE and a mixture of m-D and some of visherskiy types of polyethylene provide an exceptionally tight seal when TermoSanitari packaging material in the finished packaging containers that are favorable gas-tight packaging container. The gas impermeability of the packaging container, thus, depends on the permanence of the packaging material itself and how tight seals are obtained in the production of packaging containers from the packing material.The layer of adhesive polymer located between gazoballonnym layer and polyolefin layer consists, for example, of polyolefin modified with carboxylic acid groups, for example of polyethylene grafted with maleic acid anhydride, such as some types of Admer
The measurements were carried out on the finished structures of the packaging material, i.e. jointly extruded 5 layer structures (g/m2):
LDPE (13)/cardboard/ LDPE (10)/binder (5)/PA (barrier) (6)/binder (5)/LDPE (25).Coating weight of the barrier layer 6 and 10 g/m2respectively. RE: standard RA-6 brand V company UBE Industries Selar PA3508: amorphous polyamide.The permeability of oxygen gas RA when using only gazobetona layer is about the same as Selar PA at 0% RH, but higher at high relative humidity. Selar RA or RA as only hashbarger, thus, is not of interest from the economic point of view for ESL packaging.Methodology the test program the samples) =5 (see table. 1 in the end of the description).Conclusions: the mixture of Nylon-MXD6/PA6 has the best coloradoonline properties than amorphous RA. A mixture of Nylon-MXD6 with malono-ceramic hybrid (NCH-PA6) has the best coloradoonline properties than the corresponding mixture of Nylon-MXD6/PA6 with standard brands RA. Although the value of hashbarger were obtained for the laminate with 100% Nylon-MXD6 gazoballonnyj layer, the laminate cannot be used in practice as gazoballonnyj layer will crack and flake and will allow oxygen to penetrate into the packaging container made from it. A mixture of Nylon-MXD6 with 80 wt.% Nylon-MXD6 has the best gazoballonnyj properties than the corresponding 60% of the mixture. Although it is not shown in these examples, it was found in other tests, the optimal balance between getbasename properties and mechanical properties of packaging from the laminate obtained in the presence of about 70-80 wt.% Nylon-MXD6 in the mixture. If more than 90 wt.% Nylon-MXD6 barrier layer becomes more brittle and inflexible and, therefore, more prone to cracking and delamination.Example 2
The quality of the mixture of Nylon-MHR - polyamide:
The influence of different melting temperatures in the preparation of Nylon-MHR-RA mixture
To obtain two-phase carried the measurement, these polymers should be mixed with a low melting temperature within a relatively short time of mixing and the use of low shearing forces. In practice, the granules of different polymers are mixed dry, and then melt mixed in the extruder feeding the polymer to the extrusion head. A two-phase mixture provides the best coloradoonline properties than the single-phase mixture type.The following observation was made in experiments on a small scale with the same extrusion equipment and head. The permeability tests were performed on single-layer extruded film (20010% microns).Methodology: Mocon oxtran, the method 1000 flat samples, test gas: 100% oxygen, T= 23oC, t=24 h, RH: 50%, 1 ATM, n (number of samples)=5 (see tab. 2).Conclusion: the film produced at a lower melting temperature of the mixture had more than 100% best coloradoonline properties than film with a high melting point of the mixture, showing that the mixing at a higher temperature provides a mixture of more mixed type.Example 3
Comparison of barrier properties: 3-layer structure against five-layer
The dimension of the structures homostructure (g/m2):
binder(5)/ LDPE(20).3-layer structure (g/m2):
LDPE(16)/cardboard/RA-mix(7)/binder(5)/LDPE(20).the polyamide mixture: 7 g/m2, 75% MXD6+25% PA6-NCH.Methodology: Mocon oxtran, the method 1000 flat samples, test gas: 21% oxygen, T=23oC, t=24 h, RH: 80%, 1 ATM, n (number of samples)=2 (see tab. 3).Conclusion: the 3-layer structure provided on 40% of the best coloradobased than 5-layer structure.Example 4
The effect of the weight ratio between the outer polyethylene layers and their weight densities
Swelling was measured in two separate tests after 10 weeks of storage when cooled, each test contains 10 packs filled with orange juice, the width between the walls of the packaging container has exceeded 78 mm the Values shown in the table represent the number of millimeters, exceeding or falling below the value for reference package which has the structure:
LDPE (16)/cardboard/ LDPE (15)/ binder (5)/ EVOH (5)/ binder (5)/ LDPE (20).Similar structure with gazoballonnym layer of 75:25 Nylon-MXD6 blends with RA NCH has almost the same properties of bulges as EVOH reference sample (measured in other tests).The frequency of leaks of isbale for 15 minutes, n (number of packages)=160.Test laminates (g/m2):
LDPE (16)/cardboard/75: 25 MXD6:PA6NCH (6)/binder (3)/ LDPE (X). Next, see table. 4A, 4B.Conclusion: there is less leakage when the amount of polymer (barrier+binder+LDPE) on the inner side is high.Conclusion: the Swelling is reduced, when the amount of polymer on the outside is low, but on the inside is high.To maintain the level of swelling three-layer laminate at the same level or below the level of the reference five-layer laminate amount of LDPE in the inner layer should be at least 25 g/m2preferably at least 30 g/m2. Outer LDPE layer should be less than at least 20 g/m2preferably about 16 g/m2. At a density less than 16 g/m2the printing application of the external decorative layer may deteriorate.Test results of the swelling showed that when applying a thick inner layer on the continuous outer layer getting smaller the swelling. Unexpectedly, however, while maintaining the internal number is high and external low number of three-layer structure shows less bloating than patellifolia inside the double-wall cardboard laminate above, a total of 45 g/m2(despite the fact that the total internal polymer in the five-layer laminate is 50 g/m2).
1. The laminated packaging material containing an inner layer of paper or cardboard and gazoballonnyj layer constituting the polyamide mixture containing the condensation polymer methoxyaniline and adipic acid and a crystalline or semi-crystalline polyamide with a mass ratio of 60-90: 40-10, preferably 70-80:30-20 respectively, deposited on one side of the inner layer together with at least one layer of heat sealable plastic-polyethylene by means of co-extrusion.2. The laminated packaging material under item 1, characterized in that the polyamide blend is a two-phase immiscible composition, for which the DSC measurement shows two melting interval.3. The laminated packaging material under item 1 or 2, characterized in that the crystalline or semi-crystalline polyamide is a polyamide-6.4. The laminated packaging material according to any one of paragraphs.1-3, characterized in that the crystalline or semi-crystalline polyamide having presented the point characterized in that gazoballonnyj layer applied directly by joint extrusion of the inner layer of paper or cardboard without any intermediate lamination or adhesive layer.6. The laminated packaging material according to any one of the preceding paragraphs, characterized in that gazoballonnyj layer applied in the amount of approximately 4-12 g/m2more preferably 5-8 g/m2.7. The laminated packaging material according to any one of the preceding paragraphs, characterized in that the other side gatbering layer, facing away from the inner layer attached to the plastic layer by an intermediate layer of adhesive polymer of polyethylene grafted with maleic acid anhydride.8. The laminated packaging material according to any one of paragraphs.1-7, characterized in that the other side of the inner layer, facing away from gatbering layer, optionally covered with an outer layer of polyethylene.9. The laminated packaging material according to any one of paragraphs.1-8, characterized in that the outer plastic layer is applied in the amount of 15-20 g/m2and the amount of polyethylene in the inner layer is at least 25 g/m2preferably 30 is first gazoballonnyj layer and the second gazoballonnyj layer, printed on one side of the inner layer, both gazoballonnyj layer consist essentially of a polyamide mixture of condensation and the second crystalline or semi-crystalline polyamides.11. The laminated packaging material according to p. 10, characterized in that the innermost layer of polyethylene applied in an amount of about 7-9 g/m2.12. The production method of the laminated packaging material, which together ekstragiruyut a multilayer film including gazoballonnyj layer and a layer of heat sealable plastic under item 1, the pre-treated surface of the paper or cardboard for its activation, pre-treated with ozone contact surface of the multilayer film and then glued pre-treated surface with each other by application of pressure.13. The method according to p. 12, characterized in that the paper or cardboard is treated to activate the surface by corona discharge or flame, and the side of the layer in contact with the paper or cardboard multilayer film is treated with ozone.14. Hard to form a packaging container for storing liquid food products which are sensitive to gaseous oxygen for an extended period generowania packaging material according to any one of paragraphs.1-11.