JPS6016907B2 - Laminated structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a base material or synthetic resin having an adhesive layer comprising an ethylene-carboxyl group or a monomer copolymer containing a substituted group thereof modified with ethylenically unsaturated carboxylic acid or its anhydride and a metal compound. This relates to a laminated structure with.

In recent years, a wide variety of laminated structures have been developed that are composed of various base materials and synthetic resins, or synthetic resins, and products with higher added value that take advantage of the characteristics of each base material or synthetic resin are becoming popular. These laminates have been put into practical use, and the performance required for these laminates varies depending on the purpose of use.

For example, in the case of packaging materials, functions such as strength, water resistance, moisture resistance, gas permeability, chemical resistance, heat resistance, ultraviolet ray resistance, moldability, and heat sealability are required. On the other hand, polyolefin (
polyethylene, polypropylene, etc.) have strength, water resistance,
Although they have excellent moisture resistance, they have poor gas permeability, and saponified ethylene-vinyl acetate copolymers or nylon have excellent gas permeation resistance, but are inferior in water resistance and moisture resistance. Further, although aluminum foil has excellent UV resistance and heat resistance, it does not have heat sealability. Food packaging requires gas permeability, water resistance, moisture resistance, etc. in order to prevent food contents from discoloration, spoilage, and shape change, and to retain flavor and aroma. As for the saponified polyolefin, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer and polyolefin, or nylon and polyolefin or aluminum foil, which are laminated structures that mutually compensate for the shortcomings of nylon, aluminum foil, etc. Examples include laminated structures such as polyolefins.The functions of the above-mentioned packaging materials are utilized by appropriately selecting the constituent base materials of these laminated structures, but there is a problem with the interlayer adhesion of the components. For example, saponified ethylene-pinyl acetate copolymer (
Structures made of EVAL (hereinafter referred to as EVAL) and polyolefin, or nylon and polyolefin, have no or very weak interlayer adhesion. Conventionally, to improve interlayer adhesion, ethylene-vinyl acetate copolymers modified with ethylene, ethylene-vinyl acetate copolymers modified with unsaturated carboxylic acids, similar modified polyolefins, or ionomers (typically S manufactured by DuPont in the United States
In URLN-A, hydroxides such as Na, K, Mg, Zn, alcoholates, lower fatty acids, etc. are added to a monomer having a carboxyl group in the side chain, such as an ethylene-based polymer copolymerized with a small amount of acrylic acid. In addition, resins with most of the acid groups neutralized are used.

However, although these above-mentioned resins have good compatibility with polyolefins and have good adhesive strength, they are by no means satisfactory for all of the aforementioned saponified ethylene-vinyl acetate copolymers, nylon, aluminum foil, etc. Does not have adhesive strength.

The present invention applies ethylene-carboxyl groups or their substituent-containing monomer copolymers modified by adding ethylenically unsaturated carboxylic acids or their anhydrides to la or o of the periodic table.
This is a laminated structure with a base material, in which a modified product obtained by adding and reacting a carbonate or oxide of a group A metal is used for the adhesive layer, and the adhesive strength with nylon base material is significantly improved.

That is, the adhesive layer used in the present invention is made of ethylene-carboxyl group or its substituent-containing monomer copolymer 1
Ethylene-carboxyl group or its substituent-containing monomer copolymer modified by heating and reacting 0.01 to 10 parts by weight of ethylenically unsaturated acid or its anhydride with 0 parts by weight in the presence of an organic peroxide. and at least one carbonate or oxide of a metal from group LA or OA of the periodic table is added to the ethylene-carboxyl group or a monomer copolymer containing a substituent thereof to form a carboxylic acid group or 10 to 1/5 per mole of the anhydride group
It is a modified ethylene-carboxyl group or a monomer copolymer containing a substituent thereof, which is added at a ratio of 0 mole and subjected to a heating reaction at a temperature higher than the melting point of the ethylene-carboxyl group or a monomer copolymer containing a substituent thereof.

In the present invention, an ethylene-carboxyl group or a monomer copolymer containing a substituent thereof (hereinafter referred to as an ethylene-carboxyl group-containing monomer for brevity).

) refers to a copolymer of ethylene and acrylic acid or its ester, a copolymer of ethylene and methacrylic acid or its ester, or a copolymer of ethylene and vinyl acetate, especially ethylene-vinyl acetate copolymer. Polymers and ethylene-ethyl acrylate copolymers are preferably used. Ethylene-pinyl acetate copolymer (hereinafter referred to as
EVA) is an ethylene copolymer with a vinyl acetate content of 0.1 to 35% by weight, made by any known method, and has a melting index (hereinafter referred to as M.1.) of 0.01 to 5. /10 minutes and a density of 0.9 to 0.9 minutes is usually used. Ethylene-ethyl acrylate copolymer (hereinafter referred to as EEA) is a copolymer with ethylene containing 0.1 to 35% by weight of ethyl acrylate, and is produced by any known method. 1. Usually used is one with a density of 0.09 to 0.97 g/ground and a density of 0.01 to 5 female/10 minutes.

The ethylenically unsaturated carboxylic acids used in the present invention are monobasic unsaturated carboxylic acids such as acrylic acid and methacrylic acid, or dibasic unsaturated carboxylic acids such as maleic acid and itaconic acid, and the anhydrous Examples of the dibasic unsaturated carboxylic acid include anhydrides of the dibasic unsaturated carboxylic acids, such as maleic anhydride and itaconic anhydride.

Carbonates or oxides of metals in group LA or OA of the periodic table used in the present invention include, for example, sodium carbonate, potassium carbonate, lithium carbonate, magnesium carbonate, calcium carbonate, sodium oxide, potassium oxide, lithium oxide,
These include magnesium oxide and calcium oxide.

Regarding the production of the modified product used as the adhesive layer of the present invention, that is, the addition of the ethylenically unsaturated carboxylic acid or its anhydride and the metal compound to the ethylene-carboxyl group-containing monomer copolymer, and the reaction thereof, First, the ethylenically unsaturated carboxylic acid or its anhydride and an organic peroxide such as dicumyl peroxide, ditertiary butyl peroxide, or tertiary butyl perbenzoate are added to the ethylene-carboxyl group-containing monomer copolymer. They are allowed to coexist and heated to form a chemical bond between them.

Although the reaction can be carried out without a solvent or in the presence of a solvent, it is preferable to carry out the reaction without a solvent in terms of post-treatment steps and the like. Furthermore, the time required for the reaction varies depending on the reaction conditions, so it cannot be determined unconditionally, but a very short period of time ranging from a few seconds to several hours, generally a few minutes, is sufficient, and the reaction temperature is also dependent on the temperature at which radicals are generated. Although it depends, it is desirable to carry out the reaction at a temperature equal to or higher than the melting point of the ethylene-carboxyl group-containing monomer copolymer used, since the reaction process becomes easier especially when the modification is carried out without a solvent. Next, the metal compound is added and reacted with the reacted ethylenically unsaturated carboxylic acid group (or its anhydride group). If this order of addition is not used, the ethylenically unsaturated carboxylic acid (or its anhydride) and the metal compound will be mixed with the organic peracid (the ethylene-carboxyl group-containing monomer copolymer and the ethylenically unsaturated carboxylic acid or its anhydride). The reaction between the ethylene-carpoxyl group-containing monomer copolymer and the ethylenically unsaturated carboxylic acid or its bran water does not take place satisfactorily. In addition, when a large amount of organic peroxide is used to promote the reaction between the ethylene-carboxyl group-containing monomer copolymer and the ethylenically unsaturated carboxylic acid or its anhydride, the ethylene-carboxyl group-containing monomer copolymer A crosslinking reaction occurs, which is undesirable. As a result, problems such as a decrease in reaction efficiency, coloring of the product, or poor fluidity occur. According to the above correct order, the ethylene-carpoxyl group-containing monomer copolymer and the ethylenically unsaturated carboxylic acid (or its anhydride) will react satisfactorily, and the metal compound will react with this reaction product. , the above problems will not occur. In the production of the modified product used in the present invention, heating and malt reaction methods include methods using an extruder, methods using a kneading machine such as a Banbury mixer, and a ribbon mixer roll.
You can get caught. For example, in order to modify an ethylene-carboxyl group-containing monomer copolymer, such as EVA, with maleic anhydride and then react it with sodium carbonate, first, EVA, maleic anhydride, and an organic peroxide are thoroughly mixed, and then an extruder is used. to make modified EVA. Next, sodium carbonate is added to the modified EVA, and the mixture is melt-extruded again using an extruder to obtain a metal-bonded modified EVA. The metal-bonded modified EVA was made into a sheet, and the peaks of 178&yo-1, which are the characteristic absorption bands of maleic anhydride, and the peaks of 1550-1, which are the characteristic absorption bands of sodium carboxylate, were measured using an infrared spectrophotometer. Measure. Further, the same peak was measured after extraction for 2 hours using acetone as an extraction solvent, and the ratio before and after extraction was determined, and it was found that there was almost no change.
This indicates that almost the entire amount of the introduced metal compound additive was chemically bonded to the modified EVA.
The amount of the ethylenically unsaturated carboxylic acid or its anhydride used in the present invention is based on the weight part of EVAIO.
0.01 to 1 part by weight, preferably 0.02 to 8 parts by weight, is required.

If the amount added is too small than 0.01 part by weight, the desired adhesive strength cannot be obtained, and if it exceeds 1 part by weight, the resin will be colored or an excessive crosslinking reaction will occur, which is undesirable.

The amount of the metal compound used is 10 to 1/50 mole per mole of the carboxylic acid group or its anhydride group added to the ethylene-carpoxyl group-containing monomer copolymer.

If the amount used is too small, the adhesion will be insufficient, and if it exceeds 10 moles, bubbles may be generated or the physical properties of the ethylene-carboxyl group-containing monomer copolymer may change, causing practical problems. The base materials used in the laminated structure of the present invention include high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, polybutene-1, polyvinyl chloride, polyvinyl alcohol, nylon (6-
Synthesis of homopolymers such as nylon, 6-6 nylon, etc.), copolymers containing these monomers as main components, or synthesis of one or more of these homopolymers and copolymers as main components Examples include mixtures consisting of resins.

In addition, examples of base materials other than synthetic resins include metal plates such as aluminum, metal foils, wood, glass, paperboard, and paper materials such as cardboard. To give an example of the method for manufacturing the laminated structure of the present invention, three kinds of three-layer dies are used, and three independent extruders are used to form the intermediate layer using the modified ethylene-carboxyl group-containing monomer copolymer. The outermost layer is made of nylon and the innermost layer is made of polyolefin, and the resins melted in each extruder are joined at the tip of the die to form a three-layer laminated structure.

As the molding method, in addition to the above-mentioned inflation method or extrusion molding method such as the T-die method, blow molding method, injection molding method, etc. are also applied. The laminate structure of the present invention is composed of at least two layers of a base material and the metal-bonded modified ethylene-carboxyl group-containing monomer copolymer, and further comprises three or more layers including another layer of the same or different type as the base material. It also includes laminated structures.

As an example of the structure of the above-described laminated structure, 1 polyolefinic layer (hereinafter referred to as PO)/metal bond modified ethylene-carpoxyl group-containing monomer copolymer layer (hereinafter referred to as Me
-C)2 Nylon layer (hereinafter referred to as PA)/Me
-C3 Aluminum foil (hereinafter simply referred to as A foil)/M
e-C4 Ethylene-vinyl acetate copolymer saponified layer (
Two-layer structure such as EVAL/Me-C, 1 EVAL/Me-C/P0 2 EVAL/Me-C/PA 3 PA/Me-C/P0 4 A-line foil/Me-C/P0 5 Three-layer structure such as A foil/Me-C/PA, 6 EVAL/Me-C/PO/Me-C7 PA/M
There are four-layer structures such as e-C/PO/Me-C.

The above-mentioned two-layer structure improves heat sealing strength and is used as a simple and useful packaging material for bags, etc., and the three-layer structure EVAL/Me-C/PO or PA/
Me-C/PO has various properties such as gas permeability, mechanical strength, water resistance, and moisture resistance, and is suitable for packaging materials for foods, drugs, cosmetics, and the like.

The laminated structure of the present invention has extremely high adhesive strength, has no delamination, and can be formed into a film, sheet, tube, plate, etc. by taking advantage of the advantages of the base material of the structure, and can be used as a bag material, Used as packaging material for dishes, bottle containers, etc.

Hereinafter, the present invention will be further explained in detail using Examples and Comparative Examples.

Examples 1 to 5, Comparative Examples 1 to 8 Ethylene-vinyl acetate copolymer (M.1.0. Packing density 0
．． 9-vinyl acetate content: 6% by weight) (hereinafter referred to as EVA)
0.5 parts by weight of maleic anhydride (0.00 parts by weight) per 100 parts by weight
5 mol) and 0.05 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)-hexine-3 were thoroughly mixed using a dry blend trowel, and then 220 qo
Maleic anhydride modified EVA was extruded and granulated under the following conditions.
(hereinafter referred to as MEVA) was obtained.

Add 0.0% sodium carbonate as a metal compound to this MEVA.
32 parts by weight (0.6 mol of Na2C03/1 mol of maleic anhydride group) was added and heated at a temperature of 200°C for 5 square meters. The mixture was heated and reacted using an extruder and granulated. This granulated product (hereinafter referred to as metal bond (modified MEVA)) is used as the middle layer, and the outermost layer is made of saponified nylon-6 or ethylene-vinyl acetate copolymer (degree of saponification: 99%, ethylene content: 32 mol%). Density polyethylene (referred to as LDPE) M.1.=0.2, d
= 0.921) as the innermost layer, extruded through a 3-layer die, 3
A layer blown film was prepared. In addition, when nylon is used for the outermost layer, the average thickness of the film is 80 mm, and the innermost layer (
The thickness of each of the middle layer/outermost layer of the LDPE was 50mm/10mm/20mm.

Furthermore, when saponified ethylene-vinyl acetate copolymer is used for the outermost layer, the average thickness of the film is 75-1, and the innermost layer (L
DPE)/intermediate layer/outermost layer thickness is 40r/
It was 15/20mm. In addition, metal-bonded modified MEVA was formed into a sheet with a thickness of 0.5, overlaid with aluminum foil (thickness 0.5), placed on a press heated to 25,000 ℃, and after 5 minutes of incubation, a pressure of 10k9/s. After being allowed to stand for 1 hour under the pressure, it was immediately transferred to a press cooled to 2000℃, cooled for 5 minutes, and then taken out from the press to form a laminate. Test pieces (25 side middle) were made from these laminates and subjected to 1800 peel test (based on JIS-K6254) and oxygen permeation test (
(based on JIS-Z 1707-1975).
In Example 2, 0.0% sodium carbonate was added to the weight part of M old VAIOO.
0.02 parts by weight (0.04 moles of Na2C03/1 mole maleic anhydride groups) were added.

In Example 3, which was carried out using the same procedure as Example 1 in other respects,
0.34 parts by weight of magnesium carbonate per part by weight of MEVAIO (Maya 03 0.8 mol/1 mol maleic anhydride group)
In Example 4, 0.12 parts by weight of magnesium oxide was added to M old VAIOO.
The same procedure as in Example 1 was carried out except that parts by weight (M and o.6 mol/1 mol maleic anhydride group) were added.

In Example 5, ethylene-ethyl acrylate copolymer (hereinafter referred to as EEA) was used instead of ethylene-vinyl acetate copolymer.
(M.1.6, density 0.93 ethyl acrylate content: 1
Modified EE was prepared in the same manner as in Example 1 using
A (hereinafter referred to as MEEA) was created. 0.32 parts by weight of sodium carbonate (Na2C03
A test piece was prepared and evaluated in the same manner as in Example 1, except that 0.6 mol/1 mol maleic anhydride group was added. The test results of Examples 1 to 5, such as adhesion and oxygen permeability, were
It is shown in Table and Table 2. Comparative Example 1 used only the terminally modified ethylene-vinyl acetate copolymer used in Example 1, and Comparative Example 2 used 10 parts by weight of the ethylene-vinyl acetate copolymer of Comparative Example 1 with 0 maleic anhydride. .5 parts by weight was added and reacted (MEVA).

Comparative Example 3 used the maleic anhydride of Comparative Example 2 which was reacted with the addition of 0.005 parts by weight, which is outside the range of the present invention.
In all of the above Comparative Examples 1 to 3, no metal compound was added. In Comparative Examples 4 and 5, sodium carbonate was added to the M old VAIOO weight part by 0.00 weight part (Na2C030.008 mol/
1 mol maleic anhydride group) and 6.4 parts by weight (Na2
C03 (12.0 mol/1 mol maleic anhydride group) was added and reacted.

Comparative Example 6 used MEEA prepared in Example 5 (no metal compound added). Comparative Example 7 used Surlyn A, and Comparative Example 8 used 100 parts by weight of low density polyethylene, 0.5 parts by weight of maleic anhydride and 0.32 parts by weight of sodium carbonate (Na
2C03 (0.6 mol/1 mol maleic anhydride group) was added and reacted. Laminated bodies of Comparative Examples 7 and 8 were prepared in the same manner as in Example 1, and adhesiveness, oxygen permeability, etc. were measured.

The results are shown in Tables 1 and 3. As shown in Table 1, all laminates, such as laminates with EVAL, laminates with aluminum foil, and laminates with nylon, have high adhesion, but in particular, laminates with nylon have high adhesion. It showed remarkable effects. In addition, as shown in Table 2, the oxygen permeability of the laminated structure of the present application was slightly lower than that of the comparative example, and the laminated structure of the present application also showed good results in terms of gas permeation resistance. . In this way, the laminated structure of Fuji's invention has better gas permeation resistance and extremely superior adhesion to metals, synthetic resins, and especially nylon than conventional ones, so it can be used for film sheets, containers, tubes, etc. , has an effect that can be widely applied to plate-shaped bodies, etc.

fleet Table 2 Table 3

Claims (1)

[Scope of Claims] 1. In a laminated structure with a base material, 0.01 to 10 parts by weight of an ethylenically unsaturated carboxylic acid or its At least one oxide or carbonate of a metal in group Ia or IIa of the periodic table is added to a modified ethylene-carboxyl group or a monomer copolymer containing a substituent thereof obtained by chemically bonding an anhydride. The monomer copolymer containing the metal-bonded modified ethylene-carboxyl group or its substituent is added at a ratio of 10 to 1/50 mole per mole of the addition-reacted carboxylic acid group or its anhydride group and used as an adhesive layer. A laminated structure characterized by its use. 2. The laminate structure according to claim 1, wherein the ethylene-carboxyl group or its substituent-containing monomer copolymer is an ethylene-vinyl acetate copolymer. 3. The laminate structure according to claim 1, wherein the ethylene-carboxyl group or its substituent-containing monomer copolymer is an ethylene-ethyl acrylate copolymer. 4. The laminate structure according to claims 1 to 3, wherein the ethylenically unsaturated carboxylic acid or its anhydride is maleic anhydride. 5. The laminated structure according to claims 1 to 4, wherein the carbonate of a metal in group Ia or IIa of the periodic table is sodium carbonate or magnesium carbonate. 6. The laminated structure according to claims 1 to 4, wherein the oxide of a metal in group Ia or IIa of the periodic table is magnesium oxide. 7. The laminated structure according to any one of claims 1 to 6, wherein the base material is nylon. 8. The laminate structure according to claims 1 to 6, wherein the base material is a saponified ethylene-vinyl acetate copolymer. 9. The laminate structure according to claims 1 to 6, wherein the base material is polyethylene. 10. The laminate structure according to claims 1 to 6, wherein the base material is an aluminum foil. 11 Claims 1 to 10, wherein the base material consists of three layers laminated in this order: nylon, an adhesive layer, and polyethylene.
Laminated structure according to item 6.