JPS6036942B2 - Multilayer laminated structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multilayer laminate structure consisting of a polyolefin layer and a nylon layer.

Nylon has excellent transparency and gas permeation resistance, high rigidity, good heat resistance, and other desirable properties for packaging films and containers for foods, pharmaceuticals, and the like. but,
Nylon has the drawbacks of high hygroscopicity and poor heat-sealability, so it is often put to practical use as a laminated structure with polyolefin. In such a laminated structure, the problem is how firmly the layers can be bonded together, and this is particularly important when the laminated structure is used after being boiled, such as in retort food packaging materials. One method for obtaining a laminated structure is coextrusion, but polyolefin and nylon have poor affinity and do not adhere to each other using normal coextrusion methods. As a method for adhering a laminated structure consisting of a polyolefin and a nylon layer by coextrusion, there has been a method for adhering a polyolefin partially or completely with an unsaturated carboxylic acid or its derivative as disclosed in Japanese Patent Publication No. 51-43055. A method using modified polyolefin has been proposed.

However, this method requires long-term adhesion, harsh conditions,
For example, the adhesion when used in chick water is still insufficient.
In order to improve the adhesiveness of the above-mentioned modified polyolefin, a technique of blending a rubber component with the modified polyolefin is also known. However, rubber is easily extracted by organic solvents,
Such techniques can be problematic in oil-based food packaging film or container applications. In particular, when polypropylene is used as the polyolefin, there arises a problem that the transparency of the polypropylene compounded with rubber is impaired. An object of the present invention is to provide a multilayer laminated structure consisting of a polyolefin layer and a nylon layer, which has significantly improved glabellar adhesion, particularly interlayer adhesion when immersed in boiling water. Another object of the present invention is to provide a multilayer laminated structure that has excellent water vapor permeation resistance, gas permeation resistance, and oil resistance, and has high mechanical strength and rigidity. Still another object of the present invention is to provide a multilayer laminate structure comprising a polyolefin layer and a nylon layer with good transparency. That is, the present invention provides a crystallinity of 40% that is partially or entirely grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof.
or more polyethylene or boiling n-hebutane insoluble content 8
A polyolefin composition layer consisting of 0% or more polypropylene 99 to 5% by weight, and a crystallinity of 5% and 30% ethylene/Q-olefin copolymer 1% to 5% by weight, and a nylon layer. It is a multilayer laminated structure consisting of. In the present invention, nylon refers to, for example, nylon 6
, Nylon 66, Nylon 610, Nylon 11, Nylon IZ, etc. are long mirror synthesized polyamides having repeating amide groups as an integral part of the polymer backbone.

Nylon may contain additives such as antioxidants, ultraviolet absorbers, antistatic agents, pigments, dyes, fillers, slip agents, boar agents, retardants, plasticizers, etc. to the extent that they do not impair the purpose of the present invention. It's okay to stay. Polyethylene with a crystallinity of 40% or more, which is a raw material for the modified polyethylene used in the present invention, is an ethylene homopolymer or ethylene and other Q-olefins such as propylene, 1-butene, 3-methyl-1-butene, 1- It refers to a copolymer with hexene, 4-methyl-1-pentene, or other polymerizable monomers such as vinyl acetate, and has a crystallinity of 40% or more, preferably 70% or more.

Note that the crystallinity in the present invention is determined according to ASTM D-618.
This refers to the value measured by X-ray diffraction on a sample prepared under the following conditions. Polypropylene used in the same manner as polyethylene in the present invention has a density of 0.89 g/ to 0.91 g/
Boiling n-hebutane insoluble content 80% or less, melt index (ASTM-D-1238-6 U23000)
0.1 to 30% propylene homopolymer or propylene and 30 mol%, preferably up to 15 mol% of other Q-olefins, such as ethylene, 1-butene, 1-
Pentene, 3-methyl-1-butene, 1-hexene, 3
- Refers to a block or random copolymer with methyl-1-bentene, 4-methyl-1-pentene, etc. In the invention, part or all of the polyethylene or polypropylene is graft-modified, but in the invention, an unsaturated carboxylic acid or a derivative thereof is used as a monomer (hereinafter referred to as a graft monomer) to be grafted onto the polyethylene or polypropylene. be done.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. Derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, metal salts, etc., such as maleic anhydride, citraconic anhydride, itaconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, and methacrylate. Ethyl acid, butyl acrylate, butyl methacrylate, glycidyl acrylate, glycidyl methacrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, itacon Acid diethyl ester, acrylamide, methacrylamide, maleic acid monoamide, maleic acid diamide, maleic acid-N-monoethylamide, maleic acid-N-N'-jethylamide, maleic acid-N-monobutyramide, maleic acid-N,N'- Dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid-
N-monoethylamide, fumaric acid-N,N'-diethylamide, fumaric acid-N-monofutylamide, fumaric acid-N,N'-dibutylamide, maleimide, N-butylmaleimide, N-phenylmaleimide, acrylic acid Examples include sodium, sodium methacrylate, potassium acrylate, potassium methacrylate, and the like. Among these, maleic anhydride is most preferred. Various known methods can be used to graft the graft monomer onto polyethylene or polypropylene.

For example, it is carried out by heating polyethylene or polypropylene and grafting monomers at high temperatures in the presence or absence of a solvent, with or without the addition of a radical initiator. Other vinyl monomers such as styrene may be present during the reaction. The amount of the graft monomer grafted onto polyethylene or polypropylene (hereinafter referred to as grafting ratio) is preferably adjusted so that the grafting ratio of the entire composition is in the range of 10-4 to 5% by weight. From an industrial manufacturing point of view, the grafting rate is 10-
Preparing 2 to 10% by weight of modified polyethylene and then mixing this modified polyethylene or polypropylene with unmodified polyethylene or polypropylene is a preferred method because the concentration of the graft monomer in the composition can be adjusted appropriately. However, it is also possible to graft a predetermined amount of graft monomer to polyethylene or polypropylene from the beginning. In the present invention,
Ethylene/Q-olefin copolymers with a crystallinity of 5 and 30% that are blended into modified polyethylene or modified polypropylene include, for example, ethylene and propylene, 1-butene, 3-methyl-1-butene, 1-hexene, It is a copolymer with one or more Q-olefins such as 3-methyl-1-bentene and 4-methyl-1-pentene, and has a low crystallinity of 30% and no crystallinity.

A copolymer with a crystallinity of less than 5% is easily extracted with an organic solvent, and when modified polypropylene is used as the modified polyolefin, transparency is impaired, so it is not suitable for the purpose of the present invention and cannot be used. Among such ethylene/Q-olefin copolymers, polymerized with a vanadium catalyst, the density is 0.87 to 0.90 g/s, the ethylene content is 85 to 95 mol%, and the crystallinity is 5 to 30%.
When using the ethylene/1-butene random copolymer,
It is most preferred because it improves all of the properties of modified polyethylene or polypropylene, such as transparency, impact resistance, adhesion, and water resistance adhesion. The ethylene/Q-olefin copolymer with a crystallinity of 5 and 30% has a melt index (ASTM-○-1238 19000) of 0.1,
A range of 50 is preferred. The present invention is directed to {a-polyethylene or polypropylene with a crystallinity of 40% or more grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof; b} crystallinity of 5 to 30; % of ethylene/Q-olefin copolymer, crystallinity is 50%.
It has been found that the adhesion of the above modified polyethylene or modified polypropylene to nylon is significantly improved. The polyolefin composition used in the present invention is
(a) 5% by weight of polyethylene or polypropylene 99-free or polypropylene 99-99 or polypropylene with a crystallinity of 40% or more, one or all of which is grafted with an unsaturated carboxylic acid or its derivative;
Preferably from 99 to 7% by weight,'b} Crystallinity 5
The main component is a composition comprising from 1 to 30% by weight of ethylene/Q-olefin copolymer 1 to 5, preferably from 1 to 3% by weight.

If the amount of the ethylene/Q-olefin polymer with crystallinity of 5 or 30% is less than 1% by weight, the effect of the blending will be insufficient, and if it exceeds 5% by weight, the heat deformation resistance, rigidity, and mechanical strength will decrease. is damaged and cannot be used for retort applications. Furthermore, the adhesive strength also decreases. In addition to the above-mentioned components, the polyolefin composition used in the present invention includes weathering stabilizers, heat-resistant stabilizers, pigments, dyes, fillers, and the like.
It may contain antistatic agents, solvents, key fuel agents, plasticizers, and the like. Various known methods can be used to prepare the polyolefin composition used in the present invention. For example, after mixing each component in a ribbon blender, V-type blender, tumbler, Henschel mixer, etc., the components are kneaded with a solvent in an extruder, Banbury mixer, two rolls, kneader, etc., or each component is mixed in a solvent. After mixing the Tsuruazusa thoroughly, a method may be used such as adding a poor solvent to cause precipitation. Methods for producing a laminated structure consisting of a polyolefin composition layer and a nylon layer according to the present invention include: 1) a method in which each film or sheet is produced in advance and the two are bonded together by thermocompression; A method can be used, such as extruding and laminating the polyolefin compositions obtained by extruding the polyolefin compositions, and extruding the polyolefin compositions by melting them in separate extruders and extruding them from the same die.

In the above methods m,
A range of 0,000 to 25,000 is preferred.

The nylon resin temperature in methods (1) and '3' is 1
5030 to 300°C, especially 240oC to 270
A range of 00 is preferred. As a laminate consisting of a polyethylene composition layer and a nylon layer of the present invention, a two-layer structure of nylon/polyolefin composition, a three-layer structure of nylon/polyolefin composition, unmodified polyolefin or nylon/polyolefin composition nonylon, unmodified Examples include a four-layer structure of polyolefin/PoIJ olefin composition/nylon polyolefin composition or a five-layer structure of nylon/polyolefin composition/unmodified polyolefin/polyolefin composition/nylon. The laminated structure of the present invention has significantly improved interlayer adhesion, especially interlayer adhesion after boiling water treatment, and the conventional problem of peeling of the laminate during use has been solved.

Therefore, the high stiffness of polyolefin/nylon laminates,
Taking advantage of mechanical strength, boiling water resistance, gas permeation resistance, water vapor permeation resistance, etc., packaging materials for vegetables, meat, dairy products, etc.
Packaging containers for seasonings, edible oil, pharmaceuticals, etc., or curry,
It can be suitably used as a packaging material for retort foods such as stew. Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded. Examples 1 to 3 Modified polyethylene (hereinafter abbreviated as modified PE) obtained by grafting 2.5% by weight of maleic anhydride onto high-density polyethylene (melt index 12, crystallinity 78%), high-density polyethylene (melt index 1) , crystallinity 76%, hereinafter abbreviated as HDPE), and a mixed gas of ethylene and 1-butene (90 moles of ethylene) in hexane as a polymerization solvent using vanadium oxytrichloride and ethylaluminum sekis chloride as polymerization catalysts in a polymerization vessel. %, 1-butene 10 mol%
) and hydrogen gas, ethylene/1-butene random copolymer (melt index (190q
o)6. (Ethylene content: 91 mol%, density: 0.8 Sagi/Sakaki, hereinafter abbreviated as E8C) were mixed in a tumbler blender according to the parts by weight listed in Table 1, and then granulated with an extruder at 210 qo.

This composition was melted and supplied to a composite bottle molding die at a resin temperature of 23,000.

Meanwhile, in another extruder, nylon 6 (trademark AMILAN CMIOI)
1. Toray ■) was melted and supplied to the die at a resin temperature of 260 qo to form a blown film consisting of a polyolefin layer on the inside and a nylon layer on the outside (the thickness of the polyolefin layer was 50 mm, the thickness of the nylon layer was 20 mm). ) was molded.
Cut the test paper on the middle 15 side from the side wall of this film,
After partially peeling off the polyolefin layer and nylon layer,
Chuck speed of 10 m/s by Instron measuring machine
The peel strength of both layers was determined by measuring min.
Further, test pieces taken out after soaking in 98 oo boiling water for 1 hour were also tested in the same manner. The measurement results are shown in Table 1. Table 1 Comparative Example 1 When the same machine as in Examples 1 to 3 was used except that a composition consisting of 98 parts by weight of HDPE and parts by weight of modified PEa was used as the polyolefin composition, the initial peel strength was 40 f/15. Peel strength after rib and key water treatment is 15 female/15
It was on the side.

Comparative Example 2 The same procedure as in Examples 1 to 3 was performed except that a composition consisting of 28 parts by weight of HDPE, 2 parts by weight of modified PE, and 70 parts by weight of EBC was used as the polyolefin composition, and the initial peel strength was 350 g. /15 skin, peel strength after boiling water treatment was 20 female/15 side.

Examples 4 to 6 In a three-layer laminated sheet forming apparatus, polypropylene (melt index 0.5) was heated at 230C using the first extruder.
Polypropylene (melt index 0.5, hereafter abbreviated as TPP) and polypropylene (melt index 6.0) were mixed with 3% maleic anhydride using a second extruder.
Weight% grafted modified polypropylene (hereinafter referred to as modified PP)
23,000 ml of the composition was prepared by blending the EBC used in Example 1 and the EBC used in Example 1 as shown in Table 2.

The third extruder produces nylon (trademark Amilan CMIOI1).
(manufactured by Toray Ran) was melted to 26,000.

By supplying the three types of molten resins mentioned above to a multi-manifold type die and coextruding them, a three-layer laminate sheet of nylon/modified polypropylene composition/polypropylene (thickness of each layer of 0.1 rib/0.2 rib) is produced. /0.4 ribs) were molded. Cut a test piece of the middle 15 ribs from this sheet,
After partially peeling off the polypropylene composition layer and the nylon layer, the chuck speed was set to 10 using an Instron measuring machine.
Peel strength was measured at 0 side/min. Further, a film taken out after soaking in water vapor at 12,000°C for 1 hour was also tested in the same manner. The haze of the laminated film is ASTM-
It was measured by the method of D-1003. Comparative Example 3 The same procedure as Examples 4 to 6 was conducted except that a composition consisting of 95 parts by weight of PP and 5 parts by weight of modified PP was used as the polyolefin composition.

Comparative Example 4 Example except that ethylene-propylene rubber (melt index 0.7, density 0.8 gross/base, crystallinity 1% or less, ethylene content 80 mol%, hereinafter abbreviated as EPR) was used instead of EBC. This was done in the same manner as in step 6.

The results of Examples 4 to 6 and Comparative Examples 3 to 4 are shown in Table 2. Table 2 *120℃ water vapor - lhr

Claims (1)

[Scope of Claims] 1. Polyethylene or boiling polyethylene with a crystallinity of 40% or more that is partially or entirely grafted with at least one monomer selected from unsaturated carboxylic acids or derivatives thereof.
- Consisting of a polyolefin composition layer consisting of 99 to 50% by weight of polypropylene with a heptane insoluble content of 80% or more and 1 to 50% by weight of an ethylene/α-olefin copolymer with a degree of crystallinity of 5 to 30%, and a nylon layer. Multilayer laminated structure. 2 Density of ethylene/α-olefin copolymer is 0.8
2. The multilayer laminate structure according to claim 1, characterized in that it has a weight in the range of 7 to 0.91 g/cm^3. 3 Ethylene/α-olefin copolymer is ethylene/α-olefin copolymer
The multilayer laminate structure according to claim 1, which is a 1-butene random copolymer.