Heat-sealable multilayer film with a low gas-permeability and its use as packaging material

[Detailed Description of the Invention]

Especially suitable heat-sealing Possible to use the present invention as a film for packing to the product of the kind which needs the minimum permeability of gas and flavor or high perfume holdout for gaseous low permeability is related with the extended multilayer film. Use of the complex film with the layer in which the seal of polyolefin, an ethylene independent polymer, or a copolymer is possible is known from before for a while. The trial for which the gas permeability of a complex film is reduced has been conducted by already adding the layer of the hydrolyzed ethylene / acetic acid vinyl copolymer. In namely, German country public presentation specification No. 2644209 =GB-PS No. 1567189, The complex film which consists of polypropylene, the adhesion promotion layer of the denatured polyolefin, the hydrolyzed ethylene / acetic acid vinyl copolymer layer, and a layer of polyolefin which can be heat sealed at any time is described. however, the fatal fault that adhesion on the packaging machine parts by packing and friction with an imperfect seal and a defect takes place in order that this kind of complex film may show dissatisfied slide nature in packing at high speed comparatively -- with, it was. In the case of the complex film by the present invention, these faults are eliminated and the high-speed packaging machine is also suitable for remarkable slide nature (slippers properties) and the handling nature in machinery, And it is possible to provide the packaging material which can be used for the foodstuffs which rot easily especially for the minimum gas permeability. Therefore, the polypropylene film in which the present invention was extended in biaxial as a basis film, The adhesion promotion layer of the denatured polyolefin, the gas interception layer of the hydrolyzed ethylene / acetic acid vinyl copolymer, and the heat-sealing layer of an olefin polymer are comprised, To the at least one surface, a basis film is A. The outermost layer which can heat seal the ethylenic copolymer containing polyethylene or at least 3 % of the weight, preferably at least 4% of the weight of ethylene; B) Adhesion promotion layer of polyolefin [ Denaturation ]; C) the acetic acid vinyl unit into which at least 90% is hydrolyzed -- 50~80-mol % -- gas interception layer; of the hydrolyzed ethylene / acetic acid vinyl copolymer to contain D) The adhesion promotion layer of denaturation polyolefin; reach. E) The ethylenic copolymer layer containing polyethylene or at least 3 % of the weight, preferably at least 4% of the weight of ethylene, Or and others -- it has the layer combination thing which carried out for Arrangement in at least 1 axis at any time, and two layers A and B, D and E, layers B and C, or each of C and D may be combined with the single layer by mixing a corresponding polymer --; Layer A a) It is based on the layer in which a seal is possible, and is 0.3~1 % of the weight, preferably 0.4~0.7% of the weight of long-chain aliphatic amine, b) It is based on the layer in which a seal is possible, and they are 0.1~0.7 % of the weight, preferably 0.15~0.50 % of the weight, not mixing with polyethylene or an ethylenic copolymer -- and the softening temperature of polyethylene or an ethylenic copolymer -- a maximum of 50 degreeC -- the distributed thermoplastic polymer which is low or has high softening temperature -- and c) It is based on the layer in which a seal is possible, and is 0.1~1.2 % of the weight, preferably 0.2~0.7% of the weight of the poly Dialkylsiloxane, Or and others -- an additive agent combination thing may be contained and; and a basis film may have one layer of layer A, layer combination thing A~E, B and C, or the polymer mixture of the polymer of layers B and C on the surface besides at any time. The polypropylene of a basis film is the density of 0.90~0.91g / c.c., and 230 degreeC / pressure of 2.16kg/cm preferably.²It is isotactic polypropylene which is alike and sets and has 1~4g/the melt flow index for 10 minutes (DIN No. 53735 therefore measurement). The ethylene of the polymer of the layer which can be heat sealed is independent, or it consists of copolymers. The statistical ethylene / propylene copolymer containing high-density polyethylene or at least 4% of the weight of ethylene preferably 95% of the weight of propylene, and 5% of the weight of ethylene are used suitably. The polymers of the layer which can be heat sealed are the density of 0.895~0.960 g/c.c., and 190 degreeC/pressure 2.16 kp/cm preferably.²It should have a crystalline melting point (it measures with a polarization microscope) of 1~7g/the melt flow index for 10 minutes which can be boiled and set, and 125~148 degreeC. As for the ingredient (a) of an additive agent combination thing, long-chain fatty series tertiary amine with sufficient Then, preferably a fatty series machine are C at mono-unsaturated at any time.₁₂~C₁₈It has Carbon chain length and is two hydroxyalkyl (C).₁~C₄It is tertiary amine replaced by the basis. N, N ―Screw― (2 ―Hydroxy ethyl)- C₁₂~C₁₆Especially alkylamine is preferred. the softening temperature of the polymer in which the seal of the thermoplastic polymer which is not mixed with the polymer in which a seal is possible is possible -- a maximum of 50 degreeC -- it should be low, or should have high softening temperature, and should distribute in the polymer in which a seal is possible by particle diameter (0.01~4 micrometers, preferably 0.1~2 micrometers). Distribution into the polymer in which the seal of the polymer which cannot be mixed is possible can be performed by a publicly known standard method. The suitable polymer which cannot be mixed is polyethylene (softening temperature is about 129degreeC preferably) of thermoplastics, for example, high density, and the amount of polymers, They are ethylene/methacrylic acid copolymer (90~99degreeC), Pori Lauring lactamide (180degreeC), acrylonitrile / butadiene / methacrylate copolymer (80degreeC), and ethylene / vinyl alcohol copolymer (185degreeC). The ethylene / methacrylic acid copolymer which may exist completely partially in the form of an alkaline metal or alkaline-earth-metals salt, preferably Zn salt, or especially Pori Lauring lactamide is preferred. The poly Dialkylsiloxane used as an additive agent ingredient (c) is 10 in 20 degreeC.⁵~10⁶mPas, preferably at least 10⁶It should have the viscosity of mPas. Especially the thing for which poly dimethylsiloxane is used is preferred. the acetic acid vinyl unit into which, as for the gas interception layer, at least 90%, preferably 95% or more are hydrolyzed -- 50~80-mol % -- and -- further -- desirable -- 60~75-mol % -- it consists of included ethylene / an acetic acid vinyl copolymer. the time of measuring this polymer in 85 % of the weight of phenol, and the solvent blend of 15 % of the weight of water -- general -- desirable -- 0.07~0.17/g -- still more preferably it has the intrinsic viscosity of 0.09~0.15/g. The denatured polyolefin is used in order to make an adhesion promotion layer form. Polyolefin in which the polyolefin in question contains a carboxyl group preferably, For example, alpha, beta ―mono unsaturated dicarboxylic acid, for example, maleic acid, fumaric acid, Itaconic acid or its anhydride, acid, ester, Polypropylene or polyethylene which contains at least one sort of monomeric units from the group containing acid amide and acid imide by graft-ization; a copolymer with ethylene, acrylic acid, and/or methacrylic acid, its alkali metal salt (Zn, Na), and/or its C₁~C₄It is the saponification copolymer graft-ized by Alkyl ester or an above-mentioned acid monomer. Graft-ized output is used suitably. It is preferred to use the copolymer of the polyolefin, for example, the polypropylene, or propylene which contains a maximum of 1.0 % of the weight for the unit by which alpha, beta ―mono unsaturated-dicarboxylic-acid anhydride, for example, a maleic anhydride, and its saponification copolymer were graft-ized especially, and ethylene. When mixing an adhesion promotion polymer in either layer A in which a seal is possible, or gas interception layer C, based on a layer formation polymer, 25~30% of the weight of the denatured polyolefin is preferably used for generation of a polymer mixture to 40 % of the weight. the present invention -- therefore, by using the combination thing of an additive agent, the multilayer film which has very good slide nature in combination with good mechanical handling nature can be manufactured. It is also possible to use a film without the ordinary electric processing by which having a bad influence to the slide nature of a film is known. A crack of a film or signs of muddiness which happen when using the lubricant based on publicly known inorganic powder do not exist. The compatibility over the adhesives of the film in the object of applying a cleft strip to a surprising thing, for example is not damaged although this should be expected about the use as an additive agent of poly alkyl siloxane. therefore, especially publicly known lubricant, for example, saturation, or unsaturated fatty acid amide -- and -- comparatively -- the amount of polymers, (The substitution fatty acid amide (erucic acid amide), for example, erucic acid amide, which have 70~150 degrees of melting points C) Since use of oleic amide, An alkyl loosey fatty acid amide or N, and N ―Polyethoxylate fatty acid amide did not guarantee the suitable slide nature in a high-speed packaging machine, it was not expected that a required improvement which excels a publicly known multilayer film with the combination of the additive agent by the present invention is obtained, either. The present invention relates to using the film compound thing of the present invention as a packaging material to foodstuffs sensitive to oxygen. An additive agent can be mixed by mixture into the layer polymer in which a seal is possible, and a multilayer film can be manufactured by a standard method, for example, lamination, or fusion extrusion. Since the direct addition to the layer polymer in which the seal of an additive agent is possible eliminates the necessity for complicated additive agent / master Batches technique, it is advantageous. As for a layer combination thing, it is advantageous to apply to a basis film at a next process aside from manufacture of polypropylene. Either of the ordinary extension art can perform biaxial extension. Extension of a lengthwise direction is a ratio of 5:1~7:1 preferably, and, on the other hand, extension of a transverse direction is preferably performed by the ratio of 7:1~10:1. In the film compound thing of the present invention, the polypropylene basis film should have a thickness of 20~50 micrometers preferably, and 2~6 micrometers of layer combination things should reach preferably, and it should have a thickness of 3.5~5 micrometers still more preferably. In this case, the layer in which a seal is possible has a thickness of 0.8~2 micrometers, preferably 1 micrometer, an adhesion promotion layer has a thickness of 0.1~1 micrometer, preferably 0.4~0.6 micrometer, and a gas interception layer has a thickness of 0.2~1.2 micrometers, preferably 0.6~0.8 micrometer. Layers B and D, and A and E are preferably the same. The examining method The standard specified by the machinery driver estimated the existence of a packaging process, for example, a throughput, packing, and an adhesion thing. Comparatively, during packing at a high speed, when the disorder to these standards does not exist, it is considered that a film is a satisfying thing. The disorder which sometimes arises also means that a film is unsuitable. It is presumed by setting up a packaging machine the optimal before trial that disorder can be excepted. Under the condition (50Ns/(cm)) by which seal intensity was controlled in relation with the present invention²I am understood as power needed for stopping and having been made by 130degreeC and smooth seal Jiu for /0.5 second opening eyes. Seal intensity is denoted by Newton (N) and based on a 15-mm-wide examination strip. The action of the antistatic property of a film is estimated by ashes examination (ash test). an ashes examination is done after carrying out until Charge of the film to some extent (it rubs 3 times in the one direction using wool cloth). It is considered that a film is antistatic property enough when not absorbing the ashes of tobacco from 3-cm distance. the permeability of oxygen -- DIN No. 53380 -- therefore, it measures. muddiness -- ASTM D No. 52 [ 1003 to ] -- and a coefficient of friction is measured by DIN No. 53375. Example 1 They are N and N in order to manufacture a layer combination thing. ―Screw― (2 ―Hydroxy ethyl)- (C)₁₂~C₁₆Some of 0.5 % of the weight of ―Al kill amine and carboxyl groups exist in the form of Zn salt, and they are 190 degreeC/1 kp/cm.²It is 20degreeC, is the density of 0.985 g/c.c., and 20degreeC, and is [ 0.5 % of the weight of the ethylene / methacrylic acid copolymers which come out and have the melting point of 5g/the melt index for 10 minutes, and 99 degreeC, and ] 10.⁶4.5 % of the weight of ethylene is contained for 0.3 % of the weight of poly dimethylsiloxane which has the viscosity of mPas, and they are the density of 0.90 g/c.c., and 230 degreeC/2.16 kp/cm.²It mixes in 98.7 % of the weight of propylene ethylenic copolymers of layer A which is alike and sets and has a crystalline melting point of 5g/the melt index for 10 minutes, and 140 degreeC, And it is included, 0.7 % of the weight of polypropylene which denatured, for example, the graft-ized maleic anhydride, as an adhesion promotion layer, and they are 250 degreeC/2.16 kp/cm.²the acetic acid vinyl unit into which 96% as the polymer which is alike and sets and has 5g/a melt index for 10 minutes, and which saponified, and a gas interception layer was hydrolyzed -- 55-mol % -- carrying out a co-extrusion to the ethylene / acetic acid vinyl copolymer, and the above-mentioned propylene/ethylenic copolymer as layer E to contain Density of 0.905 g/c.c., 230 degreeC/2.16 kp/cm²It extended so that it might join to the basis film of the polypropylene which is alike and sets and has the softening temperature of 2g/the melt index for 10 minutes, and 160~166 degreeC by a standard method and the complex film which ranked next and was extended by the ratio of 10:1 in the length direction at the ratio and transverse direction of 5:1 might be obtained. The layer structure and the character of a final film are shown in the following table. Example 2 They are N and N in order to manufacture a layer combination thing. ―Screw― (2 ―Hydroxy ethyl)- (C)₁₂~C₁₆It is 0.2 % of the weight of the Pori Lauring lactamide and 20degreeC which have 0.5 % of the weight of ―Al kill amine, the density of 1.01 g/c.c., a viscosity index (based on DIN No. 53729) of 250, and the melting point of 176~180 degreeC, is the density of 0.985 g/c.c., and 20degreeC, and is 10.⁶4.5 % of the weight of ethylene is contained for 0.3 % of the weight of poly dimethylsiloxane which has the viscosity of mPas, and they are the density of 0.90 g/c.c., and 230 degreeC/2.16 kp/cm.²It mixes in 99.0 % of the weight of propylene ethylenic copolymers of Genus A which is alike and sets and has a crystalline melting point of 5g/the melt index for 10 minutes, and 140 degreeC, and, subsequently they are the density of 0.905 g/c.c., and 230 degreeC/2.16 kp/cm.²It co-extrudes by the basis film of the polypropylene which is alike and sets and has 2g/a melt index for 10 minutes, and a hardening point of 160~166 degreeC, and a standard method, and joins, And it extended so that the complex film which ranked next and was extended by the ratio of 10:1 in the length direction at the ratio and transverse direction of 5:1 might be obtained. The layer structure and the character of a final film are shown in the following table. Example 3 They are N and N in order to manufacture a layer combination thing. ―Screw― (2 ―Hydroxy ethyl)- (C)₁₂~C₁₆Some of 0.5 % of the weight of ―Al kill amino and carboxyl groups exist in the form of Zn salt, and they are 190 degreeC/1 kp/cm.²It is 20degreeC, is the density of 0.985 g/c.c., and 20degreeC, and is [ 0.5 % of the weight of the ethylene / methacrylic acid copolymers which come out and have the melting point of 5g/the melt index for 10 minutes, and 99 degreeC, and ] 10.⁶4.5 % of the weight of ethylene is contained for 0.7 % of the weight of poly dimethylsiloxane which has the viscosity of mPas, and they are the density of 0.90 g/c.c., and 230 degreeC/2.16 kp/cm.²It mixes in 98.3 % of the weight of propylene ethylenic copolymers of layer A which is alike and sets and has a crystalline melting point of 5g/the melt index for 10 minutes, and 140 degreeC, And it is included, 0.7 % of the weight of denatured polypropylene / ethylenic copolymers, for example, the graft-ized maleic anhydride, as an adhesion promotion layer, and they are 250 degreeC/2.16 kp/cm.²As the copolymer which is alike and sets and has 10g/a melt index for 10 minutes and which saponified, and a gas interception layer the acetic acid vinyl unit into which 96% of of was hydrolyzed -- 55-mol % -- carrying out a co-extrusion to the ethylene / acetic acid vinyl copolymer and the above-mentioned propylene/ethylenic copolymer as layer E to contain, and a copolymer -- the density of 0.905 g/c.c., and 230 degreeC/2.16 kp/cm²It extended so that it might join to the basis film of the polypropylene which is alike and sets and has the softening temperature of 2g/the melt index for 10 minutes, and 160~166 degreeC by a standard method and the complex film which ranked next and was extended by the ratio of 10:1 in the length direction at the ratio and transverse direction of 5:1 might be obtained. The layer structure and the character of a final film are shown in the following table.

[Table]

[Table]

[Table]

good -- good -- Good comparative example 1 They are N and N in order to manufacture a layer combination thing. ―Screw― (2 ―Hydroxy ethyl)- (C)₁₂~C₁₆4.5 % of the weight of ethylene is contained for 0.5 % of the weight of ―Al kill amine, and 0.3 % of the weight of erucic acid amide, and they are the density of 0.90 g/c.c., and 230 degreeC/2.16 kp/cm.²It mixes in 99.5 % of the weight of propylene ethylenic copolymers of layer A which is alike and sets and has a melt index of 5g/10, and a crystalline melting point of 140 degreeC, And it is included, 0.7 % of the weight of polypropylene which denatured, for example, the graft-ized maleic anhydride, as an adhesion promotion layer, and they are 250 degreeC/2.16 kp/cm.²the acetic acid vinyl unit into which 96% as the polymer which is alike and sets and has 5g/a melt index for 10 minutes, and which saponified, and a gas interception layer was hydrolyzed -- 55-mol % -- carrying out the co-extrusion of the ethylene / basis vinyl copolymer, and the above-mentioned propylene/ethylenic copolymer as layer E to contain Density of 0.905 g/c.c., 230 degreeC/2.16 kp/cm²It extended so that it might join to the basis film of the polypropylene which is alike and sets and has the softening temperature of 2g/the melt index for 10 minutes, and 160~166 degreeC by a standard method and the complex film which ranked next and was extended by the ratio of 10:1 in the length direction at the ratio and transverse direction of 5:1 might be obtained. The layer structure and the character of a final film are shown in the above-mentioned table.