JPS6326701B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on polyolefin or ethylene-
The present invention relates to a laminate using a modified polypropylene composition that has good adhesion to polar substances such as saponified vinyl acetate copolymer, nylon, polyester, glass, and metal, and has excellent transparency. In general, polypropylene has mechanical properties, transparency,
It is used in a wide range of fields due to its excellent moldability and sanitary properties, but since it is non-polar, it has poor adhesion to polar substances, and various modifications have been carried out to improve this. For example, attempts have been made to blend polar substances or to perform a graft reaction with polar monomers, but the adhesive properties are still not sufficient. Therefore, in order to further improve the adhesion, modified polypropylene grafted with unsaturated carboxylic acids (hereinafter also simply referred to as modified polypropylene) is mixed with a rubber substance such as ethylene-propylene copolymer or low density polyethylene. A method of using it as a composition has been proposed (Japanese Patent Publication Nos. 54-40112 and 54-40113). However, although the modified polypropylene composition produced in this manner has the effect of improving adhesion to some extent, it has the disadvantage that transparency is significantly reduced. Therefore, even when the modified polypropylene composition is used as an adhesive layer or a coating layer, there is a problem in that the transparency of the resulting laminated film is significantly reduced. The inventors of the present invention have conducted extensive research on laminates using modified polypropylene compositions that exhibit less deterioration in transparency and also have better adhesive properties. As a result, a modified polypropylene composition in which specific low-density polyethylene, that is, linear low-density polyethylene is mixed with modified polypropylene or a polypropylene mixture of the modified polypropylene and unmodified polypropylene, can be used as an adhesive layer or coating layer for other films. The present inventors have discovered that, by doing so, a laminate can be obtained with good adhesion without reducing the transparency of the film. In the case of the present invention, by using the modified polypropylene composition as a coating layer of a film made of a saponified ethylene-vinyl acetate copolymer having gas barrier properties, a polyamide resin, and a polyester resin, it has excellent transparency. A gas barrier laminate having the water resistance and oil resistance of the modified polypropylene composition is obtained. That is, the present invention provides a modified polypropylene grafted with unsaturated carboxylic acids or a polypropylene mixture in which a maximum of 5000 parts by weight of unmodified polypropylene is mixed with 100 parts by weight of the modified polypropylene.
5 parts of linear low-density polyethylene per 100 parts by weight
A laminate consisting of a layer (A) made of a modified polypropylene composition containing ~70 parts by weight and a layer (B) of at least one resin selected from a saponified ethylene-vinyl acetate copolymer, a polyamide resin, and a polyester resin. It is a thing. The present invention also provides a modified polypropylene grafted with unsaturated carboxylic acids or a polypropylene mixture in which a maximum of 5,000 parts by weight of unmodified polypropylene is mixed with 100 parts by weight of the modified polypropylene.
5 parts of linear low-density polyethylene per 100 parts by weight
A layer (A) consisting of a modified polypropylene composition containing ~70 parts by weight, a resin layer (B) selected from a saponified ethylene-vinyl acetate copolymer, a polyamide resin, and a polyester resin, and a layer other than the above (B) layer. A laminate comprising a thermoplastic resin layer (C) is also provided. In the present invention, one resin component used in the modified polypropylene composition is modified polypropylene. The modified polypropylene is a modified polypropylene grafted with unsaturated carboxylic acids, which is obtained by grafting polypropylene with unsaturated carboxylic acids by any method. Further, in the present invention, it is possible to use a mixture of the above-mentioned modified polypropylene and so-called unmodified polypropylene which is not subjected to a graft reaction with unsaturated carboxylic acids. The mixing ratio of the unmodified polypropylene is generally 5000 parts by weight or less, preferably 10 to 100 parts by weight, per 100 parts by weight of the modified polypropylene.
2000 parts by weight is suitable. As a method for producing modified polypropylene grafted with unsaturated carboxylic acids, for example, a method of reacting polypropylene and unsaturated carboxylic acids in a molten state (for example,
-27421), a method of reacting in a solution state (e.g., Japanese Patent Publication No. 15422/1972), a method of reacting in a slurry state (e.g., Japanese Patent Publication No. 18144/1973), a method of reacting in a gas phase (e.g., Japanese Patent Publication No. 1972-154). -77493), but among these methods, the melt-kneading method using an extruder is preferably used because it is easy to operate. Therefore, the method for producing the modified polypropylene using the melt-kneading method will be described in detail. As the polypropylene used as a raw material for the modified polypropylene or the unmodified polypropylene used as a mixture with the modified polypropylene, propylene homopolymers and copolymers can be used without particular limitation. Generally homopolypropylene, propylene-
Ethylene random copolymers, propylene-ethylene block copolymers, copolymers of propylene and α-olefin, and mixtures thereof are used. Among these, especially the melt flow index (hereinafter simply abbreviated as MFI) is 0.5 to 30.
g/10 min homopolypropylene and propylene-ethylene random copolymers are preferably used. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and their acid anhydrides, esters, amides, imides, and metal salts, such as maleic anhydride. , citraconic anhydride,
Itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate,
Maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester,
Fumaric acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid -N-
Monoethylamide, maleic acid-N,N-diethylamide, maleic acid-N-monobutylamide,
Maleic acid-N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-N-
Monoethylamide, fumaric acid-N,N-diethylamide, fumaric acid-N-monobutylamide, fumaric acid-N,N-dibutylamide, maleimide, N
-butylmaleimide, N-phenylmaleimide,
Examples include sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, and the like. Among these, it is most preferable to use maleic anhydride. The amount of such unsaturated carboxylic acids used is not particularly limited, but
To obtain modified polypropylene grafted with good unsaturated carboxylic acids, polypropylene
It is generally preferred to add 0.01 to 20 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight. Additionally, organic peroxides are used to promote the reaction between polypropylene and unsaturated carboxylic acids. Examples of organic peroxides include benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, dicumyl peroxide, α,α'-bis(t-butylperoxydiisopropyl)benzene, 2,5-dimethyl-2 ,5
-di(t-butylperoxy)hexane, 2,5
-dimethyl-2,5-di(t-butylperoxy)hexyne-3, di-t-butyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide and the like. The amount of organic peroxide added is not particularly limited, but is usually 0.005 to 5 parts by weight per 100 parts by weight of polypropylene.
Preferably it is 0.01 to 1 part by weight. Modified polypropylene grafted with unsaturated carboxylic acids is prepared by thoroughly mixing the polypropylene shown above, unsaturated carboxylic acids, and organic peroxide in a tumbler, Henschel mixer, etc. at a temperature above the melting point of polypropylene, generally above the melting point at 280°C. The grafting reaction is carried out by melt-kneading at the following temperature. The melt-kneading method is not particularly limited, and can be carried out using, for example, a screw extruder, a Banbury mixer, a mixing roll, etc., but a screw extruder is preferably used because of its ease of operation. The melt-kneading temperature and time vary depending on the decomposition temperature of the organic peroxide used, but are generally 160 to 280°C for 0.3 to 30 minutes, preferably 170 to 250°C.
℃ for 1 to 10 minutes is appropriate. Note that the melt-kneading may be performed in an inert gas stream. Therefore, in the modified polypropylene grafted with unsaturated carboxylic acids produced as described above, even if the unsaturated carboxylic acids are used in a predetermined ratio as described above, unreacted monomers inevitably remain. Therefore, in order to achieve the desired purpose, the above-mentioned modified polypropylene was further heated at 60°C or higher.
Preferably, the heat treatment is performed at a temperature of 100°C or higher. If the heating temperature is below 60°C, the treatment will take a long time and is not practical. Although the upper limit of the heating temperature is not particularly limited, it is preferably below the melting point of the modified polypropylene in order to prevent fusion of the modified polypropylene. The heat treatment means may be a conventionally known method, such as an aeration band type dryer, a material agitation type dryer, a fluidized bed dryer, a flash dryer, a spray dryer, a rotary dryer, a drum type dryer, a vacuum dryer, Although the drying can be carried out using an infrared drying device, a far-infrared drying device, a microwave drying device, etc., a hot air drying device is preferably used. Note that if the heat treatment is performed under reduced pressure, the treatment effect will be further improved. The heat treatment time is not particularly limited, but if the heating temperature is low and the resulting modified polypropylene contains a large amount of unreacted monomers of unsaturated carboxylic acids, it will take a long time; If it is small, a short time is enough. Generally, it is preferable to carry out the heat treatment so that the amount of unreacted monomer is 0.1% by weight or less. The modified polypropylene composition used in the present invention is obtained by mixing a specific amount of linear low-density polyethylene with the modified polypropylene or a polypropylene mixture of the modified polypropylene and unmodified polypropylene. The linear low-density polyethylene used in the present invention is linear low-density polyethylene that does not substantially have long chain branches. In general, a quantitative measure of the number of long chain branches G=
[η] _b / [η] _l ([η] _b is the intrinsic viscosity of branched polyethylene, [η] _l is the intrinsic viscosity of linear polyethylene with the same molecular weight as branched polyethylene) is approximately 1 (conventional normal The G value of high-pressure low-density polyethylene is 0.1 to 0.6), and the number of short chain branches is 100 carbon atoms in the main chain.
1 to 3 pieces per piece, density 0.910 to 0.945, MFI
(ASTM D1238, 230°C) 0.3 to 30 g/10 min is preferably used. The method for producing linear low density polyethylene is not particularly limited. To give an example of a typical manufacturing method, a pressure of 7 to 45 Kg/ ^cm2 (usually 2000 to 3000 Kg/cm2 for high-pressure low density polyethylene)
cm ² ), at a temperature of 75 to 100°C (120 to 250°C for high-pressure low-density polyethylene), 1-butene, 1-methylpentene, 1-hexene, and octene were α of -1st class
- There is a method of copolymerizing ethylene using olefin as a comonomer. In addition, as a polymerization method,
A solution method, liquid phase method, slurry method, liquid phase method, fluidized bed gas phase method, stirred bed gas phase method, etc. can be used. The amount of linear low density polyethylene in the modified polypropylene composition is 5 parts by weight per 100 parts by weight of the modified polypropylene or polypropylene mixture.
The amount is from 70 parts by weight, preferably from 10 to 50 parts by weight. If the amount of linear low-density polyethylene blended is less than the above range, the effect of improving adhesion will be small, and if it exceeds the above range, not only will the adhesion decrease, but also the transparency and mechanical strength will decrease significantly. Undesirable. The modified polypropylene or polypropylene mixture and the linear low density polyethylene can be mixed using a tumbler, a Henschel mixer, or the like. Further, it is more preferable to melt-knead these mixtures using, for example, a screw extruder, a Banbury mixer, or a mixing roll. The following embodiments are also possible as a method for producing the modified polypropylene composition used in the present invention. That is, a predetermined amount of linear low-density polyethylene is mixed with modified polypropylene produced by a melt-kneading method or a polypropylene mixture of the modified polypropylene and unmodified polypropylene, melt-kneaded again, and then heat-treated to obtain a modified polypropylene composition. obtain. Alternatively, a modified polypropylene composition can be obtained by mixing polypropylene, linear low-density polyethylene, unsaturated carboxylic acids, and organic peroxide, melt-kneading the mixture, and then subjecting the mixture to heat treatment if necessary. The modified polypropylene composition produced as described above desirably contains 0.01 to 5% by weight of unsaturated carboxylic acid. When the content of unsaturated carboxylic acids is less than 0.01% by weight, the effect of improving adhesion is small, and when it exceeds 5% by weight, not only does the manufacturing cost increase, but the effect of improving adhesion becomes saturated.
Furthermore, the modified polypropylene composition may contain heat-resistant stabilizers, weather-resistant stabilizers, lubricants, antistatic agents, nucleating agents, fillers, pigments, dyes, flame retardants, anti-blocking agents, etc. to the extent normally used. good. In the present invention, the saponified ethylene-vinyl acetate copolymer to be laminated with the layer made of the modified polypropylene composition has an ethylene content of 20 to 60, considering gas barrier properties, oil resistance, water permeability, etc.
Mol%, preferably 25-50 mol%, degree of saponification 93%
Above, preferably 96% or more is generally used. Polyamide resins are linear polymers with acid amide bonds obtained by (a) condensation of diamines and dicarboxylic acids, (b) condensation of amino acids, and (c) ring opening of lactams, such as nylon 6, nylon 6, 6 , nylon 6, 10, nylon 11, nylon 12, etc. can be used. Furthermore, polyester resin is obtained by condensation of saturated dibasic acid and glycols,
Specifically, polyethylene terephthalate obtained from ethylene glycol and terephthalic acid; polyethylene containing saturated dibasic acids such as phthalic acid, isophthalic acid, sebacic acid, adipic acid, azelaic acid, glutamic acid, succinic acid, and oxalic acid as copolymerized components. Terephthalate copolymers; and polyethylene terephthalate copolymers containing 1,4-cyclohexanedimethanol, diethylene glycol, propylene glycol, etc. as diol components; or blends thereof are used. As a method for laminating the polar resin and modified polypropylene composition exemplified above to a desired thickness,
Known lamination methods such as an in-die lamination method, an outside-die lamination method, and thermocompression bonding using a press are employed. In the laminate consisting of a polar resin layer and a modified polypropylene composition layer obtained by the present invention,
Each layer may be unstretched, uniaxially stretched, or biaxially stretched, or may be uniaxially or biaxially stretched after lamination. The laminate obtained by the present invention has excellent transparency, gas barrier properties, oil resistance, water resistance, and high strength, so it can be suitably used as a food packaging material. In addition to the above-described laminate structure consisting of a polar material layer and a modified polypropylene composition layer, the present invention also provides a laminate in which another resin layer is laminated to add a new function. Specifically, 5 to 70 parts by weight of linear low-density polyethylene is added to 100 parts by weight of modified polypropylene grafted with unsaturated carboxylic acids or a polypropylene mixture in which up to 5,000 parts by weight of unmodified polypropylene is mixed with 100 parts by weight of the modified polypropylene. a modified polypropylene composition layer (A) containing 2 parts by weight, a resin layer (B) selected from saponified ethylene-vinyl acetate copolymer, a polyamide resin, and a polyester resin, and a thermoplastic resin layer other than (B) ( C) It is a laminate consisting of. Thermoplastic resins other than (B) include polypropylene, polyethylene, polybutene-1, ethylene-
Vinyl acetate copolymer, ionomer resin, cis-
Examples include 1,4-polybutadiene. One or more layers selected from these thermoplastic resins are laminated on the laminate consisting of (A) and (B) with or without the modified polypropylene composition of the present invention.
As the lamination method, the method described above can be used as is. Although the lamination mode of the laminate in the present invention is not particularly limited, the following are preferred examples. (1) Polar resin/modified polypropylene composition/polypropylene, (2) low density polyethylene/polar resin/modified polypropylene composition/polypropylene, (3) ethylene-vinyl acetate copolymer/polar resin/modified polypropylene composition/polypropylene , (4) ionomer resin/polar resin/modified polypropylene composition/polypropylene, (5) cis-1,
4-Polybutadiene/polar resin/modified polypropylene composition/polypropylene, (6) ethylene-propylene random copolymer/modified polypropylene composition/polar resin/modified polypropylene composition/polypropylene, (7) low density polyethylene/modified polypropylene composition Product/Polar resin/Modified polypropylene composition/Polypropylene, (8) Ethylene-vinyl acetate copolymer/Modified polypropylene composition/Polar resin/Modified polypropylene composition/Polypropylene, (9) Ionomer resin/Modified polypropylene composition/Polar Resin/modified polypropylene composition/polypropylene, (10) cis-1,4 polybutadiene/
Examples include modified polypropylene composition/polar resin/modified polypropylene composition/polypropylene. Among these, (1) laminate is a composite film and 2
When it is axially stretched, it becomes a composite biaxially stretched polypropylene film that has excellent gas barrier properties, oil resistance, water resistance, and good transparency. Also
When the laminate of (2) to (10) is biaxially stretched, it is a composite biaxially stretched polypropylene film that has excellent gas barrier properties, oil resistance, water resistance, heat sealability, and good transparency. becomes. The laminate of the present invention described above has excellent adhesion and extremely high peel strength because of the modified polypropylene composition layer, and there is little decrease in transparency. By further laminating other resins with or without the modified polypropylene composition on the laminated structure consisting of the modified polypropylene composition and the polar resin, properties other than gas barrier properties, oil resistance, water resistance, etc. can be improved. In addition, a laminate with new properties and good transparency can be obtained. The present invention will be described below with reference to Examples, but the present invention is not limited thereto. Note that the various physical properties in this specification were measured by the following methods. ΓMFI 2160 at 230℃ by ASTM D1238−52T
It was measured by a load of g. Amount of maleic anhydride in Γ graft reaction A film with a thickness of approximately 0.1 mm was formed by heat pressing, extracted with acetone for 6 hours, and then heated at a temperature of 50℃ for 24 hours.
The infrared absorption spectrum of the sample vacuum-dried for an hour was measured, and the amount of graft-reacted maleic anhydride was determined from the absorption peak intensity of maleic anhydride at 1780 cm ^-1 . Γ Adhesive Strength For adhesion between saponified ethylene-vinyl acetate copolymer, nylon, and polyethylene terephthalate, both were coextruded, cooled and solidified, and then cut into 2 cm width pieces in the longitudinal direction, and the T-peel strength was measured. Γ Transparency Measured by ASTM D1003. Examples 1 to 5 and Comparative Examples 1 to 11 MFI = 0.6 g/10 min, 100 parts by weight of propylene-ethylene random copolymer with ethylene content of 2.0% by weight, 2 parts by weight of maleic anhydride, 2,5-dimethyl-2 ,5-di(t-butylperoxy)hexane
0.12 parts by weight, 0.1 parts by weight of butylated hydroxytoluene, and 0.1 parts by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and L/D=40 with L/D=24.
Melt-kneading pelletization was performed at 220°C using a mmφ extruder, followed by heat treatment at 145°C for 4 hours using a constant temperature dryer to obtain modified polypropylene grafted with maleic anhydride (hereinafter also referred to as grafted PP). MFI of this graft PP = 52.7g/
10 minutes and contained 0.5% by weight of maleic anhydride grafted. Next, 15 parts by weight of the graft PP was added with MFI = 4.0 g/10 min unmodified homopolypropylene in the proportions shown in Table 1, specific gravity 0.922, G = 0.98, MFI = 5.4 g/10 min linear low density polyethylene, specific gravity 0.920, G=
0.25, MFI = 4.0 g/10 min high pressure process low density polyethylene, specific gravity 0.960, G = 1.0, MFI = 5.0 g/10 min linear high density polyethylene, ethylene content 70% by weight, MFI = 5.3 g/10 ethylene-propylene random copolymer, ethylene content 80% by weight,
Mix ethylene-butene-1 random copolymer of MFI=6.4g/10min, L/D=24, 40mmφ
Melt-knead and pelletize at 220℃ using an extruder.
A modified polypropylene composition was obtained. The obtained modified polypropylene composition was formed into a 70μ film and the haze was measured. The results are shown in Table 1. Further, Table 2 shows the adhesive strength between the saponified ethylene-vinyl acetate copolymer, nylon 6, and polyethylene terephthalate. Note that the adhesive strength was determined as follows. That is, the modified polypropylene composition was heated at 200°C from a 40 mmφ extruder with L/D = 20 and a saponified ethylene-vinyl acetate copolymer (MFI = 19.5
g/10 minutes, ethylene content 45 mol%, saponification degree 99%
above), nylon 6 and polyethylene terephthalate from a 30mmφ extruder with L/D=24, respectively.
Coextrusion T- at 200℃, 250℃ and 270℃ respectively
Extrusion through a die to form coextruded sheets of the modified polypropylene composition with a thickness of 0.5 mm, saponified ethylene-vinyl acetate copolymer, nylon 6 and polyethylene terephthalate with a thickness of 0.2 mm, respectively,
T-peel strength was measured at a tensile speed of 20 mm/min.
Further, the haze of the laminate was measured. The results are also shown in Table 2.

【table】

【table】

[Table] Example 6 MFI=1.0g/10min homopolypropylene 290
The mixture was put into an extruder equipped with a T-die set at .degree. C. to obtain a sheet with a thickness of 1.5 mm. Next, this sheet was stretched 5 times in the longitudinal direction using a roll-type stretching machine with a roll surface temperature set at 155°C to produce a uniaxially stretched polypropylene sheet with a thickness of 0.3 mm. Then 250℃
The modified polypropylene composition of Example 3 was charged into an extrusion laminator set at 1, and extrusion laminated to a thickness of 20 μm on the uniaxially stretched polypropylene sheet. Furthermore, using an extrusion laminator set at 200°C, the saponified ethylene-vinyl acetate copolymer used in Example 3 was extruded and laminated to a thickness of 80μ on the modified polypropylene composition side of the above laminated sheet, and uniaxially stretched. polypropylene/
A three-layer laminate sheet of modified polypropylene composition/saponified ethylene-vinyl acetate copolymer was obtained. This laminated sheet was stretched 10 times in the transverse direction using an oven-type stretching machine set at an air temperature of 160°C to obtain a laminated composite film with a thickness of 40 μm. Each layer of this film is non-peelable and has an oxygen permeability of 7.1cc/ ^m2・24hr・
atm, haze was 1.8%. Comparative Example 12 Example 6 except that the modified polypropylene composition of Comparative Example 6 was used in Example 6.
I did the same thing. The obtained film had an oxygen permeability of 7.3 cc/m ² ·24 hr · atm and a haze of 3.5%. Example 7 MFI=1.0g/10min homopolypropylene 290
The mixture was put into an extruder equipped with a T-die set at .degree. C. to obtain a sheet with a thickness of 1.5 mm. Next, this sheet was stretched 5 times in the longitudinal direction using a roll-type stretching machine with a roll surface temperature set at 155°C to produce a uniaxially stretched polypropylene sheet with a thickness of 0.3 mm. Next, 20μ of the modified polypropylene composition of Example 4/40μ of the saponified ethylene-vinyl acetate copolymer/20μ of the modified polypropylene composition was applied onto the uniaxially stretched polypropylene sheet using a two-type, three-layer coextrusion laminator set at a die temperature of 200°C. Co-extrusion laminated so that Furthermore, using a laminator set at a die temperature of 280°C, 20μ of a propylene-ethylene random copolymer with an MFI of 8.0g/10 minutes and an ethylene content of 3.5% by weight was extruded and laminated on the modified polypropylene composition side of the laminated sheet, followed by uniaxial stretching. A five-layer laminate sheet of polypropylene/modified polypropylene composition/saponified ethylene-vinyl acetate copolymer/modified polypropylene composition/propylene-ethylene random copolymer was obtained. This laminated sheet was stretched 10 times in the transverse direction using an oven-type stretching machine set at an air temperature of 160°C to obtain a laminated composite film with a thickness of 40 μm. Each layer of this film was non-peelable, had an oxygen permeability of 12 c.c./m ² ·24 hr · atm, a heat seal temperature of 126°C, and a haze of 2.0%. Comparative Example 13 The same procedure as in Example 7 was conducted except that the modified polypropylene composition used in Comparative Example 7 was used. The oxygen permeability of the obtained flume was 13
cc/ ^m2・24hr・atm, heat seal temperature 131℃,
Haze was 4.0%. Example 8 MFI=0.6 g/10 min, 90 parts by weight of propylene-ethylene random copolymer with ethylene content of 2.5% by weight, 10 parts by weight of the linear low density polyethylene used in Examples 1 to 5, 0.3 parts by weight of maleic anhydride Parts by weight, 0.1 parts by weight of benzoyl peroxide, 0.1 parts by weight of butylated hydroxytoluene, and 0.1 parts by weight of calcium stearate were mixed in a Henschel mixer for 5 minutes, and melt-kneaded at 220°C using a 40 mmφ extruder with L/D=24. , 3 at 140℃ using a constant temperature dryer.
Heat treated for hours. This modified polypropylene composition was grafted with 0.21% by weight of maleic anhydride and had an MFI of 8.5 g/10 minutes. on the other hand,
MFI=1.0g/10min homopolypropylene at 290℃
Thickness is increased by an extruder equipped with a T-die set to
I made a 1.5mm sheet. Next, this sheet was stretched 5 times in the longitudinal direction using a roll-type stretching machine with a roll surface temperature set at 155°C to produce a uniaxially stretched polypropylene sheet with a thickness of 0.3 mm. Next, the die temperature
The above modified polypropylene composition (20μ/ethylene-
A 4-layer sheet of modified polypropylene composition/saponified ethylene-vinyl acetate copolymer/modified polypropylene composition/uniaxially oriented polypropylene is coextruded and laminated so that the saponified vinyl acetate copolymer 40μ/modified polypropylene composition 20μ. I got it. This laminated sheet was stretched 10 times in the transverse direction using an oven-type stretching machine set at an air temperature of 145°C.
A 38μ laminated composite film was obtained. Each layer of this film is non-peelable and has an oxygen permeability of ^13c.c./m2 .
24 hours atm, heat sealing temperature was 132°C, and haze was 2.5%. Comparative Example 14 The same procedure as in Example 8 was conducted except that the high-pressure low-density polyethylene used in Comparative Examples 4 to 8 was used instead of the linear low-density polyethylene. The oxygen permeability of the obtained film was ^14c.c./m2 .
24 hours atm, heat sealing temperature was 135°C, and haze was 5.2%.

Claims (1)

[Scope of Claims] 1. Linear low density based on 100 parts by weight of modified polypropylene grafted with unsaturated carboxylic acids or a polypropylene mixture in which up to 5000 parts by weight of unmodified polypropylene is mixed with 100 parts by weight of the modified polypropylene. A layer (A) consisting of a modified polypropylene composition containing 5 to 70 parts by weight of polyethylene and a layer (B) of at least one resin selected from saponified ethylene-vinyl acetate copolymer, polyamide resin, and polyester resin. A laminate. 2. 5 to 70 parts by weight of linear low-density polyethylene per 100 parts by weight of modified polypropylene grafted with unsaturated carboxylic acids or a polypropylene mixture in which 100 parts by weight of the modified polypropylene is mixed with a maximum of 5000 parts by weight of unmodified polypropylene. A layer (A) consisting of a modified polypropylene composition containing
A laminate comprising a resin layer (B) selected from a saponified ethylene-vinyl acetate copolymer, a polyamide resin, and a polyester resin, and a thermoplastic resin layer (C) other than the above (B) layer.