JPS602984B2 - Manufacturing method for resin laminates - Google Patents

Description

Detailed Description of the Invention The present invention uses a gas barrier resin selected from vinylideso chloride resin, thermoplastic polyester resin, polyamide resin, or saponified product of ethylene/vinyl acetate copolymer and polystyrene resin with excellent rigidity. This invention relates to a method for producing a laminate that is used as a substrate and has excellent oil resistance, gas barrier properties, and high strength.

Conventionally, saponified products of vinylidene chloride resin, thermoplastic polyester resin, polyamide resin, and ethylene/vinyl acetate copolymer (hereinafter referred to as "saponified EVA") have been extremely good in terms of gas barrier properties, oil resistance, mechanical strength, etc. However, it is extremely expensive and has high water permeability, making it difficult to use as a single material in the food industry, automobile industry, etc.

On the other hand, highly rigid polystyrene resins such as high-impact polystyrene and A-spot resin are not only inexpensive, but also have good mechanical strength, vacuum formability, extrusion moldability, and hygiene. It is used for a wide range of purposes.

However, such highly rigid polystyrene resin has poor gas barrier properties and oil resistance, so when used as containers for foods such as mayonnaise and soy sauce, it is impossible to preserve food for a long time, and when used as containers for gasoline. When this happens, there are drawbacks such as a large amount of gasoline being lost and the container becoming wet and deformed. Various proposals have been made to improve the drawbacks of polystyrene resins, but these have complicated the manufacturing process and increased costs. Satisfactory results have not been obtained due to constraints such as limited application design.

One solution to this problem is to consider laminating it with resins such as thermoplastic polyester, polyamide, and saponified EVA, which have properties that compensate for the drawbacks of polystyrene resins, but originally polystyrene resins As expected from its chemical structure, it is non-polar and has a low affinity with the three resins mentioned above, which has the disadvantage that it easily peels off when both resins are simply melted and pressed together.

Although there has been a proposal to provide an adhesive layer between these two resin layers, this requires a separate adhesive coating process, which has the disadvantage of complicating the manufacturing process. An object of the present invention is to provide a method for producing a laminate that has the advantages of gas barrier properties, water resistance, and low cost, and in which both resin layers are firmly bonded with an adhesive.

The present invention aims to achieve the above object,
Wind: Polystyrene resin 'B' selected from impact-resistant polystyrene, mottled resin A, gas barrier resin selected from saponified ethylene-vinyl acetate copolymer, polyamide resin, vinylidene chloride resin, and thermoplastic polyester resin. 'Modified ethylene-vinyl acetate copolymer having a component concentration of unsaturated carboxylic acid or its acid anhydride of 0.001-10% by weight. The present invention provides a method for producing a resin laminate characterized by extrusion.

The most important resin used in the present invention is high impact polystyrene (hereinafter referred to as "HIPS").

), Amo resin is widely known in the industry, and HIPS is, for example, by melting 5-2% by weight of butadiene-styrene rubber into 90-8% by weight of styrene monomer, adding water and a suspending agent to this solution. It is a blended polystyrene resin obtained by blending and manufacturing by a polymerization method such as bulk polymerization, solution polymerization, or suspension polymerization. Also, ABS resin is styrene 70-8
Resin "SAN resin" obtained by polymerization or suspension polymerization of 30 to 2 parts by weight of acronitrile to 95 parts by weight
~70 parts by weight of butadiene-acrylonitrile rubber (
Butadiene 80-6% by weight, acrylonitrile 20-6%
A blend type containing 5 to 3 parts by weight of 4% by weight), or a blend type obtained by dissolving 10 to 4 parts by weight of polybutadiene in 10 parts by weight of a mixed monomer of styrene and acrylonitrile and suspending the mixture. Examples include polymerization types.

Although the chemical composition of the saponified ethylene-vinyl acetate copolymer (saponified EVA) used in the '81 resin is not limited, it is considered from the viewpoint of gas barrier properties, oil resistance, and water vapor permeability. and the ethylene content is 25-50
It is preferable to use one obtained by saponifying mol% of ethylene-vinyl acetate copolymer so that the degree of saponification becomes 93% or more, preferably 96% or more.

Polyamide resin is a linear synthetic polymer having an acid amide bond obtained by condensation of 'a} diamine and dicarboxylic acid, {b) condensation of amino acid, and {condensation of c-lactam,
For example, nylon 6 (polycaproamide), nylon 61
6 (polyhexamethylene adefamide), nylon 6
・10 (polyhexamethylene sebamide), nylon 1
1 (polyundecamide), nylon 12, etc. can be used.

Thermoplastic polyester resins are obtained by condensation of saturated dibasic acids and glycols, such as polyethylene terephthalate obtained from ethylene glycol and terephthalic acid, phthalic acid, phthalic acid, cepacic acid, adipic acid, azelaic acid, and glutaric acid. , polyethylene terephthalate copolymers containing saturated dibasic acids such as succinic acid and oxalic acid as copolymer components, and polyethylene containing 1,4-cyclohexanedimethanol, diethylene glycol, propylene glycol, etc. as diol components as polymer components. It is a terephthalate copolymer, polybutylene, or a blend thereof.

The vinylidene chloride resin is obtained by copolymerizing 75 to 85 parts by weight of vinylidene chloride monomer with 25 to 15 parts by weight of vinyl chloride monomer or acrylonitrile monomer or a mixture thereof (emulsion polymerization, suspension polymerization). It is.

Next, the modified EVA used as the adhesive resin 'C} is an ethylene-vinyl acetate copolymer (hereinafter referred to as "EV") having a melt index of 0.5 to 20 and a vinyl acetate content of 5 to 70% by weight.
It is obtained by graft polymerizing an unsaturated carboxylic acid or its acid anhydride to an unsaturated carboxylic acid or its anhydride (hereinafter referred to as "unsaturated carboxylic acid").

) include acrylic acid, maleic acid, fumaric acid, itaconic acid, himic acid, or anhydrides thereof. Among these, acrylic acid or maleic anhydride is preferred. A method for modifying the EVA is to graft-polymerize the unsaturated carboxylic acid or its anhydride to EVA.

Graft polymerization can be carried out by melting and mixing EVA, an unsaturated carboxylic acid for grafting, and a catalyst in an extruder, or by adding an unsaturated carboxylic acid for grafting and a catalyst to EVA resin particles suspended in an appropriate solvent. There are methods such as adding it and heating it. The unit concentration of unsaturated carboxylic acid in the modified EVA is from 0.001 to 1% by weight.

These adhesive resins may be used alone or in combination with low density polyethylene, EVA, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylate copolymer, ethylene-ethyl acrylate copolymer, etc. Polymers or their Na, K, Ag, Cu, Ba, Z
It may contain 1 to 8% by weight of metal salts such as n, etc. Also, to improve adhesiveness, 0.3 to 5% by weight of polyamide resin, polyester resin, saponified EVA, or ethylene-propylene rubber, Styrene-butadiene rubber,
A rubber material such as butadiene rubber or ethylene-propylene terpolymer may be contained in an amount of 3 to 35% by weight.

Instead of modified EVA, polypropylene of the same type as EVA,
Unsaturated carboxylic acid grafted products of polyolefins such as low-density polyethylene and high-density polyethylene have strong adhesive strength with gas barrier resins, but with polystyrene resins, the resulting laminate, such as balisong or sheet, can be blow-molded. This is not practical because the polystyrene resin and adhesive layer will peel off when blowing or spreading using vacuum forming, press forming, pressure forming, etc.

In the present invention, methods for melt-coextruding and laminating polystyrene resin, polyester resin, polyamide resin, saponified EVA, and vinylidene chloride resin via modified EVA include an in-die lamination method and an outside-die lamination method. In-die laminate provides stronger adhesion. Examples are shown below to specifically explain the present invention.

Example 1 Ethylene-vinyl acetate copolymer “Cucalon” manufactured by Mitsubishi Yuka Co., Ltd.
Eva 41H” (skin 2, specific gravity 0.938, VA content 15
(wt%) 10 parts by weight, 1 part by weight of maleic anhydride, 2.
After adding 0.5 parts by weight of 5-dimethylhexane-2,5-di/·hydroperoxide, it was mixed in a Henschel mixer, and 220q was added in an extruder with a diameter of 100 g and L/D of 28.
It was extruded at 100 ml, and made into pellets after being covered with water.

(After dissolving this modified EVA in boiling xylene and reprecipitating it in a large amount of acetone, the concentration of maleic anhydride in the modified EVA was measured using infrared absorption spectroscopy, and it was found to be 0.0% by weight. ) Using this modified EVA as an adhesive, saponified EVA (EVAL,
(saponency scale mol%, ethylene content $wt%, vinyl acetate content 1wt%, vinyl alcohol content 41wt%) and impact-resistant polystyrene HT88-5 manufactured by Mitsubishi Monsanto were laminated in the die using a T-die, The mixture was then cooled to obtain a laminate sheet having a four-layer structure (modified EVA/saponified EVA/modified EVA/m2; wall thickness 20 mm/20 mm/20 mm/40 mm).

The extrusion temperature of each resin during lamination is modified EVA1
80°C, saponified EVA 210°C, HmS 21000. The peel strength of the tied sheet is the same as that of modified EVA/saponified EV.
0.8k9/arc between A, 0.5 between modified EVA/HmS
It was k9′.

Using this 100mm wide laminated sheet and a multi-cavity (12 x 12) mold, two plug-assisted vacuum forming operations were performed.
The process was carried out at a temperature of 20 qo to obtain a cup with a diameter of 6 mm and a depth of 40 mm.

There was no peeling between the resin layers of this cup.

Example 2 A mixture of the modified EVA 5 used in Example 1, 4 parts by weight of Cucarone Eva Day 41, and 3 parts by weight of styrene-butadiene rubber was used as an adhesive resin.
Mitsubishi Monsanto ABS resin TFX76 instead of mS
A laminated sheet was obtained in the same manner as in Example 1, except that Example 1 was used.

The peel strength between each resin layer is ABS/adhesive layer 0.5k9/
The saponified EVA/adhesive layer had a thickness of 0.7k9', and even when this laminated sheet was vacuum formed, there was no interlayer separation of the resins.

Example 3 A mixture of 49.5 parts by weight of Cucaron EVA 41 and 0.5 parts by weight of Nylon 6 in the modified EVA 5 used in Example 1 was used as an adhesive layer, and polyethylene terephthalate (Amite A manufactured by AKZO) was used as an adhesive layer. 200) as the inner layer and HI Kyo (HT Iso-5) as the outer layer, multiple pins with a three-layer structure of 20 mm inner layer, 20 r adhesive layer, and 1 skin outer layer were made by in-die lamination blow molding method.

The resin temperature during molding was 200°C for the outer layer and 1 for the adhesive layer.
The temperature was 80° C., the inner layer was 270 ○, and the resin pressure in the laminated portion was 5k9/m in gauge pressure of the die.

The interlayer peel strength of each resin in the obtained hollow bottle was 1.0k9/kite between the adhesive layer and polyethylene terephthalate, and 0.5k9/kite between the adhesive layer and the m tower, which is practically acceptable. There were no problems.

Example 4 A hollow bottle was molded in the same manner as in Example 4, except that polyvinylidene chloride was used instead of polyethylene terephthalate and the resin temperature of the inner layer was set to 210°C.

Peel strength between polyvinylidene chloride and adhesive layer is 0.5k
9/ Peel strength between adhesive layer and H grip S is 0.5k9'
skin, and there were no practical problems. ◎Peel strength: T-beer Peel width 1.5cm, tensile speed 5cm/min.In addition, in the laminated structure of the present invention that requires oil resistance, it is preferable that the inner layer is made of gas barrier resin. In addition, for those requiring chemical resistance, the gas barrier resin layer is coated with modified EVA as in Example 1,
It is best to use this as the inner layer.

Example 5 Styrene-butadiene rubber (Califlex TRII0 manufactured by Shell Co., Ltd.) was added to the weight part of the modified EVA7 used in Example 1.
2) An adhesive resin containing 3 parts by weight was used as an adhesive resin, and impact-resistant polystyrene (K-Resin KR-0 manufactured by Philips Co., Ltd.) was used as an adhesive resin.
A laminated sheet was obtained in the same manner as in Example 1, except that Example 1) was used.

The peel strength between each resin eyebrow is H flower S/adhesive layer 0.7k9'
The composition was saponified EVA/adhesive layer 0.8k9/skin, and even when this laminated sheet was vacuum formed, there was no delamination between the resin layers.

Comparative Example 1 Unmodified EVA used in Example 1 (M12, specific gravity 0.93
A laminated sheet was obtained in the same manner as in Example 1, except that the VA content was 14% by weight.

The peel strength between each resin is HmS/adhesive layer 0.1k9'
It was saponified EVA/adhesive layer 0.2k9/arc, and when this laminated sheet was vacuum formed, peeling occurred between each layer,
It was impractical.

Claims (1)

[Claims] 1 (A) Polystyrene resin selected from impact-resistant polystyrene and ABS resin (B) Gas barrier property selected from saponified ethylene-vinyl acetate copolymer, polyamide resin, vinylidene chloride resin, and thermoplastic polyester resin Resin (C) Modified ethylene-vinyl acetate copolymer having a component concentration of unsaturated carboxylic acid or its acid anhydride from 0.001 to 10% by weight Adhesion of resins (A) and (B) above to (C) 1. A method for producing a resin laminate, characterized by melt coextrusion through a plastic resin.