JPS5995139A - Laminated structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated structure, and more specifically, a resin layer comprising a saponified ethylene-vinyl acetate copolymer having a modified ethylene copolymer resin and/or a modified ethylene copolymer resin. In a laminated structure comprising at least a layer of a polyolefin resin, the modified ethylene copolymer resin has a density of 0.890 to 0.890 obtained by copolymerizing an α-olefin such as ethylene.
950 (J/cc, Mel I index 0.01~
50 (1/10 min, 100 m of ethylene copolymer with 0.15 or less terminal vinyl groups per 1000 carbons)
0.01 to 2 parts of unsaturated carboxylic acid or its derivative
Regarding a laminated structure characterized by using a modified ethylene copolymer resin grafted with a 0-vehicle part, it has various properties such as resistance to gas permeation such as oxygen, carbon dioxide, and aroma (mechanical properties, etc.). It has excellent properties and can be used as food packaging film or packaging material for food containers.

Conventionally, thermoplastic resins, especially polyolefin resins, have been known for their excellent transparency and flexibility. ! 3 and I! It is widely used as a packaging material for food products from various viewpoints.

However, polyolefin resins have drawbacks such as high permeability to gases such as oxygen and carbon dioxide, and the inability to preserve foods for long periods of time.

On the other hand, ethylene-vinyl acetate copolymer cyanide is generally known as a resin having the lowest gas permeability.

One example of a film that takes advantage of the mutual properties of these resins is a laminated film made of a combination of different polymers.

For example, as a food packaging film that requires excellent gas barrier properties and P1 sealing properties, among the laminated films, the above-mentioned polyolefin resin and ethylene
Examples include laminated films of resins made of saponified vinyl acetate copolymers. However, these resins have poor thermal fusion bonding properties and have weak adhesion between the two, resulting in delamination N1, making them very impractical.

In order to improve the above-mentioned drawbacks, methods have been proposed in which the two resins are laminated by interposing an adhesive or by surface treatment, but these methods require complicated processes and have tQI problems. This leads to various problems, such as the fact that the molding method is difficult to use, or the adoption of efficient molding methods such as the JJ extrusion method is restricted.

In addition, attempts have been made to improve the adhesion to polyolefin resins containing unsaturated carboxylic acids in the graph I to improve the adhesion to the saponified products containing edylene-vinyl nitrate. Does not have adhesive strength.

The present invention has been made to solve the above problems,
The aim is to provide a laminated structure with excellent adhesiveness.
Ultimately, resistance to gas permeation such as oxygen, carbon dioxide, and aroma,
It has various excellent properties such as mechanical properties, and is preferably used as a packaging material for food packaging films or food containers.

As a result of intensive studies in line with this purpose, the present inventors have found that by using a modified ethylene copolymer selected from a specific ethylene copolymer resin, saponified ethylene-vinyl acetate copolymer and (4) The present invention was achieved by discovering the basis for a laminated structure having adhesive strength.

That is, the present invention provides a resin layer made of a saponified ethylene-vinyl acetate copolymer and a modified ethylene copolymer resin J:
and/or a layer of a polyolefin resin having a modified ethylene copolymer, wherein the modified ethylene copolymer resin has a density of 0.890 obtained by copolymerizing ethylene and an α-olefin. ~0.
950g/cc, melt index 0.01-50a
/10 minutes, to 100 parts by weight of an ethylene copolymer having 0.15 or less terminal vinyl groups per 1000 carbons,
A laminated structure characterized by using a modified ethylene copolymer resin grafted with 0.01 to 20 parts by weight of an unsaturated carboxylic acid or a derivative thereof.

The ethylene-α-olefin copolymer (hereinafter simply referred to as ethylene copolymer) used in the present invention includes ethylene-propylene copolymer, ethylene-brown-1
copolymers, ethylene-hexene-1 copolymers, ethylene-octene-1 copolymers, ethylene-4/methyl/pentene-1 copolymers, and (J) mixtures thereof. A copolymer with 3 to 12 α-olefins is preferred.

The method for producing the ethylene-α-olefin copolymer is not particularly limited, and includes gas phase polymerization using high, medium, and low pressure methods, slurry polymerization, and solution polymerization.

The above ethylene copolymer has a density of 0.890 to 0.95.
0(J,'cc, preferably 0.91-0.94(]
/CC, melt index is 0.01 to 50 (+ /
10 minutes, preferably 0.1 to 20 g/10 minutes, and the terminal vinyl group in the molecule is ioo.

A specific range of 0.15 pieces or less per 7J-bong is selected.

The above density is 0.89Q! If it is less than J/CC, the moldability will be affected (0.950g), and if it exceeds /cc, the adhesion will be lower (It is not preferable).
- Index (hereinafter simply referred to as MI) is 0. OIM
If the molding time is less than 10 minutes or exceeds 5 og/10 minutes, the molding will be undesirable.

Also, the terminal vinyl group in the molecule of the ethylene copolymer is i o
If the number exceeds 0.15 per carbon, intramolecular crosslinking occurs during modification, resulting in a slow decrease in Ml, which is not preferable.

The unsaturated carboxylic acids or derivatives thereof of the present invention are monobasic acids such as acrylic acid, methacrylic acid, and methyl methacrylic acid, dibasic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and hymic acid, or these acids. anhydride,
Nisdel, amides, imides or metal salts,
At least one of these is used, and maleic acid or maleic anhydride is particularly preferred.

The unsaturated carboxylic acid or its derivative is used in an amount of 0.01 to 20 parts by weight, preferably 0.03 to 10 parts by weight, per 100 parts by weight of the ethylene copolymer. −[2
The ff') of the unsaturated carboxylic acid or derivative is 0.
If the amount is less than 0.01 parts by weight, the adhesiveness will decrease and the desired effect will not be obtained. Moreover, if the number of hanging parts exceeds 20, the resin will become colored or gelatinized, which is not preferable as it will cause the generation of foreign matter.

The modified ethylene copolymer resin used in the present invention is
[0.01 to 20 parts by weight of an unsaturated carboxylic acid or its derivative is grafted to 100 parts by weight of the Boorene copolymer in the presence of an organic peroxide, and the modification is carried out in an extruder or in a panbury. Michili etc.) 1? , kneading (a method to avoid denaturation by melt-mixing in a solvent-free environment such as in a layer,
Alternatively, there are no particular limitations, such as a method of denaturation by heating and mixing in a solvent such as an aromatic mHX hydrocarbon such as benzene, xylene, toluene, or an aliphatic hydrocarbon such as hexane, heptane, ACtane, etc., but it is easy to operate and inexpensive. For certain reasons, it is preferable to carry out the process in an extruder.

The above-mentioned modified ethylene copolymer resin can be used by using the modified product as it is, or by adding a specified amount of the modified product to a polyolefin resin such as unmodified polyethylene or polypropylene or a compatible thermoplastic resin. Good too. The above blend may be a tri-blend or a melt-blend. Examples of the organic peroxides include benzoyl peroxide, lauryl peroxide, azobisisobutyroni-1-lyl, dicumyl peroxylide, t-butyl hydroperoxide, α, α'
-bis(t-butylperoxydiisopropyl)benzene, di-t-butylper A21-side, 2,5-di(
Organic peroxides such as (butylperoxy)hexyne are preferably used.

The laminated structure of the present invention comprises a resin layer made of a saponified ethylene-vinyl acetate copolymer (hereinafter simply referred to as EVAL 1), the modified ethylene copolymer resin and/or a polyolefin containing the modified ethylene copolymer resin. It consists of at least a layer of resin. (1) of the laminate of the present invention
4 or above, the EVAL layer and the modified ethylene copolymer resin layer (hereinafter simply referred to as MPE), or the modified ethylene copolymer resin such as EVΔLFf1, which is a common polyolefin resin (
Hereinafter, it will be simply referred to as 1]0 and 2), and includes a multilayer laminate that is based on a structure consisting of a modified polyolefin resin layer (hereinafter referred to as MPO) blended with a predetermined amount of other thermoplastic resins. For example, [■△I single layer/MPL layer/P○ layer, EV△LJim/MP01iSJ
/PO layer, MPEIiiJ/EVALIi/MPF
Ii? i/POfFt etc. (7) Species 'Z''
Form rli4 all-inclusive.

The saponified ethylene-vinyl acetate copolymer according to the present invention () has a composition with an ethylene content of 20 to 50 mol% and a degree of monotonylation of the vinyl acetate portion of 90 mol% or more.I':Lt ,stomach.

In addition, thermoplastic resins include copolymers of polyebulene and α-olefins produced by high, medium, and low pressure processes, ]-dylene-vinyl acetate copolymers, polypropylene, copolymers of propylene and other α-olefins, Polyolefin resins such as polybutene-1 and poly4-methyl-pentene-1,
Examples include polyvinyl chloride resin, polyvinylidene chloride resin, polyamide 4BJ resin, poly1 stellate resin, polyvinyl alcohol resin, and mixtures thereof.

As a method for manufacturing the V4 layer structure of the present invention, a multi-layer die is used to extrude it in one batch. In addition to extrusion molding methods such as the multilayer inflation method, which involves joining 8 melted resins at the tip of a die to form a laminated structure, and the Gui method, blow molding methods and injection molding methods are also applicable.

The laminated structure of the present invention has mechanical strength, water resistance, moisture resistance or gas permeability. It has various characteristics of I:'J and is applied to films, sheets, tubes, containers (bottles), etc., and is used in many fields such as food, medicine, and cosmetics, which require particularly high barrier properties. It is useful as a material for use.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 (Production of modified ethylene copolymer) 1-ethylene-butene-1 copolymer (density 0.921Q/C
C, melt index 1.0 (J / 10 min, terminal vinyl / L [0,09f [Xl / 1 (1'C;)'1
To 71 parts of 0011' were added 1 part of anhydrous maleic M O,3Iff and 2,5 dimedyl, 2,5 di(turn 1 fributyl bar A x) hexyne-30,05 parts, and the mixture was stirred and blended using a Henschelmikiner. The blend was grafted using an extruder at 230° C. and a residence time of 100 seconds to obtain a modified ethylene copolymer (MPE).

(Manufacture of laminated structure Iho) Using an inflation molding machine, the M P E O J:
] L-tyrene-vinyl acetate saponide (trade name: EVAL ED-F, especially manufactured by Rale, EVAL) resin is supplied to a multilayer die, and the die temperature is 230°C, and the resin is laminated by merging at the river surface of the die lip to form two layers. A three-in-one film was molded consisting of a Vi layer film (laminated structure).
The thickness is M P E 70μ/EV A L 30μ.

A test piece with a width of 25 ml 1 1 was made from the above laminated film, and the adhesive strength was determined as the interlayer peel strength when it was pulled at an angle of 180 degrees and a take-up speed of 50111+11/min using a Tensilon method tensile tester. It is shown in Table 1. The method for measuring the terminal vinyl group in the molecule is to prepare a sheet with a thickness of 6 mm and use an infrared absorption spectrum at a wavelength of 11.
The absorbance at 0.03μ was measured and calculated using the following formula.

/ HlooC= K lo(] I./IX'1/
rH where, d: Density of polyethylene J: Thickness of sheet 1°: Absorbance of base I; Characteristic absorption luminous intensity K; Constant (for wavelength 11.03μ (yo 0.11G)
9-Lid-1-''-Eudylene-propylene copolymerized iho (density (1,922
All Examples except that g/cc, M I 1,0 (1/10 min, 0.08 terminal vinyl groups/10"C) was used in place of the tyrene-butene-1 copolymer of Example 1. A laminated structure was manufactured in the same manner as in Example 1, and the adhesive strength was measured in accordance with Example 1. The results are shown in Table 1.

Example 3 Instead of the ethylene-butene-1 copolymer of Example 1, ethylene-hexene-1'14 was combined with a density of 0.912 g/
cc, M I 1. h/10 min, terminal vinyl group 0
．． A laminated one-layer structure was manufactured in the same manner as in Example 1 except that 08 pieces/103G> was used, and the adhesive strength was measured in accordance with Example 1. The results are shown in Table 1.

J-M l) E 30 car 61% created according to previous example 1
The unmodified ethylene-butene-1 copolymer has a density of 0.92.
1 (J/cc, MIO, 25 seconds, 710 minutes, 0.09 terminal vinyl groups/10"C) (hereinafter referred to as L
1'7k of the modified product (MPE+L-LDPE) mixed with 70% by weight of -L DI) E and -J-). A laminated structure was produced using this modified product in the same manner as in Example 1, and the adhesive strength was measured in accordance with Example 1, and the results are shown in Table 1.

: fr'f: (?J 5 Low density polyethylene (density 0.922 g/cc, M
I O, 25s 710 minutes, product name: 1 bottle of modified LDPE mixed with 30% (MlcE 10L D P
E) is 19. Using this modified product, the same E as in Example 1 was prepared.
VAL and LDPIE (1'1 stone Rex [1'F1
02), set up a 3-layer die at inflation 1, and use E VA L/M P L +L l) P
E / L D P E 3 layers 414 construction 1 water obtained, EV
The adhesive strength between AL/MPE and LDPE was measured and the results are shown in Table 1.

Comparison Example 1 Instead of the ethylene-butene-1 co-τE polymer of Example 1, a nytylene-propylene copolymer (outside the range used in the present invention) (density 0.!118 g/cc, M I 55 (1
An attempt was made to obtain a laminate in the same manner as in Example 1 using 0.07 terminal vinyl groups/103G), but MPE
was too weak to be molded.

ILJL-Dylene-butene-1 copolymer, which is outside the range used in the present invention, has a density of 0.921! II/CG, M I 1g,
A laminated structure was produced in the same manner as in Example 1 using 710 minutes and 0.2 terminal vinyl groups/10'C), and the adhesive strength was measured. The results are shown in Table 1. The bond W, adhesive strength [clo
, the width was as low as 5kg/2CTI1.

Comparison Example 3 Modified Aimetsumar resin (Sangatsu Borikmical ((
A laminated structure was produced in the same manner as in Example 1, except that the adhesive strength was measured, and the results are shown in Table 1. As a result, the adhesive strength was as low as 0.3k (J/2cu width).

Claims (1)

[Claims] 1.] A resin layer made of a saponified diylene-vinyl acetate copolymer and a layer of a polyolefin resin having a modified ethylene copolymer resin and/or a modified ethylene copolymer resin. At least in the laminated structure, the modified ethylene copolymer resin includes ethylene, α-′
Copolymerized with A1 nofin! T IFj density 0
, 890-0.950g/cc, null 1-index 0.01-50o/10min, the terminal vinyl group in the molecule is i
ooo 0.15 or less ethylene copolymer per carbon, 100 parts by weight of unsaturated carboxylic acid or its derivative
．． 2. A laminated structure characterized in that the ethylene copolymer is an ethylene-butene-1 copolymer. The laminated structure according to Claim 1. 3. The laminated structure according to Claim 1 or 2, wherein the unsaturated carboxylic acid or its derivative is maleic anhydride.