JPH10180954A - Thermoplastic laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin laminate excellent in oil resistance and heat resistance while maintaining excellent characteristics of a styrene resin such as rigidity and transparency. SOLUTION: This is a thermoplastic resin laminate comprising at least three layers, wherein one surface layer is composed of a styrene resin or a styrene resin composition, and the other surface layer is composed of an olefin resin or an olefin resin composition. And the intermediate layer is an unsaturated carboxylic acid, an unsaturated carboxylic acid ester,
Contains 20 to 100% by weight of an ethylene copolymer comprising ethylene and at least one compound selected from unsaturated carboxylic anhydride and vinyl acetate, and 80 to 0% by weight of a propylene resin or an ethylene resin. A laminate made of a thermoplastic resin, which is an adhesive resin layer made of an ethylene copolymer or a resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin laminate comprising at least three layers. More specifically, the present invention relates to a thermoplastic resin laminate having at least three layers, which is excellent in oil resistance and heat resistance while maintaining rigidity and transparency.

[0002]

2. Description of the Related Art A sheet made of a styrene resin composition is used as a raw material for vacuum / pressure molding as one of its uses because of its excellent appearance such as rigidity, processability and gloss. And is mainly used as a food container such as an instant food container or a one-way lunch box.

[0003] Recently, these food containers are required to have oil resistance on the inner surface of the container in order to contain foods containing an oil component. In addition, the container may be heated by a microwave oven with the food in it. In this case, especially if there is a food with an oil component, the location will be extremely hot, so in addition to oil resistance, heat resistance Is required. The styrene-based resin container has low oil resistance and heat resistance, and often cannot meet the above requirements.

[0004] In order to meet such demands, there has been proposed a method of forming a container using a sheet of a blend of a styrene resin composition and an olefin resin composition. However, in this case, the properties of the styrene-based resin such as rigidity are deteriorated, and at the same time, the styrene-based resin and the olefin-based resin generally have poor compatibility. Therefore, it is necessary to use a compatibilizer. Is very expensive, which leads to an increase in cost.

In an attempt to impart oil resistance and heat resistance to a container without reducing rigidity, a film formed using a blend of a styrene-based resin composition and an olefin-based resin composition has been used. A method of thermally laminating the inner surface of a resin container has been proposed. However, this method has a problem that the transparency of the film is reduced.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic resin laminate having excellent oil resistance and heat resistance while maintaining the excellent properties of styrene resin such as rigidity and transparency. is there.

The present inventors have conducted intensive studies on a laminate having a layer made of a styrene-based resin, and found that one surface layer was made of a styrene-based resin or a styrene-based resin composition, and the other surface layer was made of an olefin-based resin. A layer composed of an olefin-based resin composition and an intermediate layer thereof are composed of a specific adhesive resin layer, by forming a laminate of at least three layers,
The inventors have found that the object of the present invention is achieved, and have completed the present invention.

[0008]

That is, the present invention provides a thermoplastic resin laminate comprising at least three layers,
One surface layer is a layer made of a styrene resin or a styrene resin composition, the other surface layer is a layer made of an olefin resin or an olefin resin composition, and the intermediate layer is an unsaturated carboxylic acid, unsaturated carboxylic acid ester, Ethylene copolymer 20 comprising at least one compound selected from saturated carboxylic anhydride and vinyl acetate and ethylene
A thermoplastic resin laminate comprising an ethylene-based copolymer or a resin composition, which contains 100 to 100% by weight and 80 to 0% by weight of a propylene-based resin or an ethylene-based resin. It is. Hereinafter, the present invention will be described in detail.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the thermoplastic resin laminate (hereinafter referred to as "laminate") of the present invention, one surface layer is made of a styrene resin or a styrene resin composition, and the other surface layer is made of an olefin resin. And a layer comprising an olefin-based resin composition, and the intermediate layer is formed from ethylene and at least one compound selected from unsaturated carboxylic acids, unsaturated carboxylic esters, unsaturated carboxylic anhydrides and vinyl acetate. 20 to 100% by weight of an ethylene copolymer and a polypropylene resin or a polyethylene resin 80
It is a laminate of at least three layers, which is an adhesive resin layer containing an ethylene-based copolymer or a resin composition containing 0 to 0% by weight. The laminate generally has a thickness of 10 μm to 1 mm and includes a film or a sheet. Here, in general, a film having a thickness of 10 to 100 μm is distinguished from a film, and a film having a thickness exceeding 100 μm is distinguished from a sheet.

In the above laminate, the layer made of a styrene resin or a styrene resin composition has a thickness of 5 to 500 μm.
m, the layer made of an olefin-based resin or an olefin-based resin composition is preferably 3 to 400 μm in thickness, and the adhesive resin layer is preferably 2 to 100 μm in thickness.

[0011] The adhesive resin layer comprises an unsaturated carboxylic acid,
Ethylene copolymer 20 to 100 consisting of ethylene and at least one compound selected from unsaturated carboxylic esters, unsaturated carboxylic anhydrides and vinyl acetate
Weight% and propylene resin or ethylene resin 80
An adhesive resin layer containing an ethylene-based copolymer or a resin composition containing 0 to 0% by weight.

Specific examples of the above-mentioned ethylene copolymer include ethylene-unsaturated carboxylic acid copolymer and ethylene-unsaturated carboxylic acid copolymer.
Unsaturated carboxylic acid ester copolymer, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester-
Examples include terpolymers of vinyl acetate and multi-component copolymers of ethylene and two or more unsaturated carboxylic esters. The content of the repeating unit derived from ethylene in the ethylene copolymer is usually 40 to 95% by weight, and the content of the repeating unit derived from the above comonomer compound is usually 5 to 60% by weight.

Examples of the unsaturated carboxylic acids include acrylic acid and methacrylic acid. Examples of the unsaturated carboxylic acid ester include methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate,
Examples include stearyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, and glycidyl methacrylate. Examples of the unsaturated carboxylic anhydride include maleic anhydride.

Preferred specific examples of the ethylene copolymer include ethylene-acrylic acid copolymer and ethylene-acrylic acid copolymer.
Methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate -Glycidyl methacrylate copolymer, ethylene-methyl methacrylate-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate copolymer, ethylene-maleic anhydride copolymer, and the like. Among these, an ethylene-methyl methacrylate copolymer or an ethylene-vinyl acetate copolymer is more preferred.

Further, among the above ethylene copolymers,
Those having a solubility parameter (SP value) of 8.45 to 8.70 are more preferable. Here, the solubility parameter (S
P value) is Hildebrand-Scatchchar
The theory of d defines the attractive force between molecules. For a detailed explanation, see a general textbook on polymer chemistry,
For example, it is described in "Polymer Blend, Saburo Akimoto et al., CMC Co., Ltd., 4th printing, pages 125-144 (1991)". Here, the above-mentioned solubility parameter used a method proposed by Small and obtained by calculation from the molecular structure. For more information on this method, see “Journal of Applied Chemi.
Stry), vol. 3, pages 71-80 (1953), whereby the solubility parameter was calculated using the following equation: SP value = 値 F _i / V = ρΣΣF _i / Here, F _i represents the molar attraction force of a constituent group such as an atom or atomic group constituting a molecule, a bond type, V represents a molar volume, ρ represents a density, M represents a molecular weight, and repeated for a polymer. Indicates the molecular weight of a unit (ie, a monomer unit).
The value of F _i are described in the two documents Smal
The value of 1 was used. Copolymers [rho, for .SIGMA.F _i and M, [rho of the homopolymer of the monomer units constituting the copolymer, and calculating the sum of those multiplied by the mole fraction of monomer units in the numerical values of .SIGMA.F _i or M Used.

The method of mixing the resin composition used as the adhesive resin layer is not particularly limited, and may be a method of mixing the respective resin pellets by dry blending, or a method of melting and kneading them by an extruder. Any method of re-granulating into pellets may be used.

The styrenic resin or styrenic resin composition constituting one surface layer is not particularly limited. For example, the gel amount is 0 to 20% by weight and the melt flow rate is 2 to 20 g / 10 minutes. Are preferred. Here, the melt flow rate of the styrene resin or the styrene resin composition conforms to JIS K7210,
This is a value measured under the conditions of 0 ° C. and a load of 5 kgf. Further, the gel amount is a weight ratio of the soft component particles in the styrene resin or the styrene resin composition, and can be measured by the following method. That is, 0.5 g of a styrene-based resin or a styrene-based resin composition was weighed (weight: W1), and the sample was treated at room temperature (about 23 ° C.) with methyl ethyl ketone /
Dissolve in 50 ml of a mixed solvent of methanol (10/1 volume ratio). Next, the insoluble matter at the time of the dissolution is isolated by centrifugation, and the insoluble matter is dried and its weight (W2) is measured. The content of the soft component particles in the styrene resin or the styrene resin composition is determined by (W2 / W1) × 100 (%).

Styrene resin or styrene resin composition
Is polystyrene having a weight average molecular weight of 200,000 to 400,000
0 to 100% by weight and an average gel particle diameter of 0.1 to 5
Rubber-modified police having μm and gel amount of 5 to 30% by weight
Styrene resin containing 100 to 0% by weight of styrene or
Styrene resin compositions are preferred. Here, rubber modified
The average gel particle size of polystyrene is the soft component in the resin.
And the number average particle diameter is determined by the following method.
In other words, transmission electron micrographs of rubber-modified polystyrene
With true image analysis, the particle size (D_i) And the number n _iTo
It is calculated by the following formula. Number average particle size = Σ (n_i・ D_i ^Two) / Σ (n_iD_i)

The method of mixing the polystyrene and the rubber-modified polystyrene is not particularly limited, and may be a method of mixing the polystyrene pellets and the rubber-modified polystyrene pellets by dry blending, or a method of melt-kneading them with an extruder and then mixing the pellets. Any of the methods of re-granulating in a state may be used.

The styrene resin or the styrene resin composition may contain a lubricant, an antistatic agent,
Antioxidants, heat stabilizers, ultraviolet absorbers, pigments, dyes, styrene-butadiene block copolymers and other elastomers can be included, and within a range that does not impair the effects of the present invention, such as mineral oils A plasticizer may be contained.

The olefin resin or the olefin resin composition constituting the other surface layer includes, for example, a propylene resin, a propylene resin composition, an ethylene resin, an ethylene resin composition or a mixture thereof.
Among these, a propylene-based resin or a propylene-based resin composition having a melt flow rate of 0.5 to 20 g / 10 minutes is preferable from the viewpoint of the balance between heat resistance and oil resistance, film transparency, film strength, and extrudability. . here,
The melt flow rate of the propylene-based resin or the propylene-based resin composition is a value measured according to the method of Condition 14 of JIS K7210.

The laminate of the present invention is produced, for example, by co-extrusion of each of the above layers. Examples of the method of co-extrusion include a method of co-extrusion using a film processing machine or a sheet processing machine including a co-pressing T-die extruder, and a method of forming using a co-pressing blown film forming apparatus. Can be

[0023]

As described above, according to the present invention,
A laminate made of a thermoplastic resin having excellent oil resistance and heat resistance can be provided while maintaining excellent properties of the styrene resin such as rigidity and transparency.

[0024]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited to these examples. In addition, among the evaluation items, the items other than the items described above were implemented as follows. (1) Rigidity (tensile elastic modulus) In the take-off direction (MD), width 20 mm, length 100 m
Toyo Seiki Seisakusho Co., Ltd.
A tensile test was performed using a T-type strographic tester under the conditions of a tensile speed of 1 mm / min and a distance between chucks of 60 mm, and the tensile modulus was determined by the following equation. Tensile modulus (kg / cm ² ) = 80% of yield stress / sample strain = 80% of yield strength (kg) / (sample thickness (cm) × sample width (cm)) × distance between chucks ( c
m) / elongation at 80% of yield strength (cm) (2) Film transparency The haze value was measured according to JIS K7105. The smaller the value, the better the transparency. (3) Heat resistance and oil resistance To the obtained molded product, apply 15 ml of pene
It was left in a constant temperature layer at 0 ° C. and 130 ° C., and the time required for Penelough oil to leak at each temperature was examined. The larger the value, the better the heat and oil resistance.

Example 1 As one surface layer, a rubber-modified polystyrene (Sumibright, trade name, manufactured by Sumitomo Chemical Co., Ltd., average gel particle size 0.2
μm, gel amount 26% by weight, melt flow rate 4 g / 1
0 min) The pellet is used as the other surface layer with homopolypropylene (manufactured by Sumitomo Chemical Co., Ltd., trade name: Noblen Y1).
01, a melt flow rate of 12 g / 10 minutes) as an intermediate layer, an ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Aklift WM)
403, methyl methacrylate content 38% by weight, SP value 8.50) 70% by weight of pellets and polypropylene homogenous (trade name: Noblen Y101, manufactured by Sumitomo Chemical Co., Ltd.)
Melt flow rate 12 g / 10 min) Using a mixed pellet of 30% by weight of each pellet, a cast film forming apparatus (3 types and 3 layers co-press T-die manufactured by Modern Machinery Co., Ltd.)
Width: 600mm, Extruder A: 50mmφ, Extruder B: 4
(0 mmφ, extruder C: 40 mmφ), the laminated film was processed under the extrusion conditions shown in Table 1, a cooling roll temperature of 60 ° C, and a take-up speed of 30 m / min.
Further, the thickness of each layer was measured by cross-sectional observation using an optical microscope. Table 1 shows the results.

Comparative Example 1 The same rubber-modified polystyrene pellets as used in Example 1 were used, and the same extruders A and B as the cast film forming apparatus used in Example 1 were used. Extrusion conditions, chill roll temperature 60 ° C, take-off speed 30
The monolayer film was processed under the condition of m / min. Table 1 shows the results.

Comparative Example 2 64% by weight of the same rubber-modified polystyrene pellets as used in Example 1, 27% by weight of the same polypropylene pellets as used in Example 1, and styrene-ethylene as a compatibilizer Propylene-styrene block copolymer resin (Septon 210 manufactured by Kuraray Co., Ltd.)
4, styrene content 65% by weight) A mixture of 9% by weight of pellets was mixed well, and the same extruders A and B as the cast film forming apparatus used in Example 1 were used, and the extrusion conditions shown in Table 1 were used. The monolayer film was processed under the conditions of a cooling roll temperature of 60 ° C. and a take-up speed of 30 m / min.
Table 1 shows the results.

Example 1 satisfying the conditions of the present invention is excellent in all evaluation items. On the other hand, Comparative Example 1 using a single-layer film made of rubber-modified polystyrene is inferior in heat resistance and oil resistance. Comparative Example 2 using a single-layer film made of a blend of rubber-modified polystyrene and polypropylene is inferior in transparency and rigidity of the film.

[0029]

[Table 1] Example Comparative Example 11 2 ──────────────────────────── Laminated 3 layers Single layer Single layer Extruder A (Surface 1) PS PS PS / PP Resin temperature ( ℃) 230 230 230 Extrusion amount (kg / h) 20 20 20 Extruder B (intermediate layer) Adhesive layer PS PS / PP Resin temperature (℃) 190 230 230 Extrusion amount (kg / h) 5 10 10 Extruder C ( Surface layer 2) PP--Resin temperature (℃) 230--Extrusion amount (kg / h) 5--Laminate thickness (μm) 30 30 30 Surface layer 1 thickness (μm) 20--Intermediate layer thickness (μm) 5- − Thickness of surface layer 2 (μm) 5 − − Evaluation result Rigidity (kg / cm ² ) 16000 16500 13000 Film transparency (haze%) 16 17 73 Heat and oil resistance 120 ° C (min) 45 5 70 130 ° C (min) 35 3 60 ─────────────────────────────────

Claims (7)

[Claims] 1. A laminate made of a thermoplastic resin comprising at least three layers, wherein one surface layer is made of a styrene resin or a styrene resin composition, and the other surface layer is an olefin resin or an olefin resin composition. And the intermediate layer is an ethylene-based copolymer of ethylene and at least one compound selected from unsaturated carboxylic acids, unsaturated carboxylic esters, unsaturated carboxylic anhydrides and vinyl acetate, and ethylene. A thermoplastic resin laminate comprising an ethylene-based copolymer or a resin composition containing 100% by weight and 80 to 0% by weight of a propylene-based resin or an ethylene-based resin. 2. The thermoplastic resin laminate according to claim 1, wherein the thickness of the adhesive resin layer is 2 to 100 μm. 3. The thermoplastic resin laminate according to claim 1, wherein the ethylene copolymer has a solubility parameter (SP value) of 8.45 to 8.70. 4. The thermoplastic resin laminate according to claim 1, wherein the ethylene copolymer is an ethylene-methyl methacrylate copolymer or an ethylene-vinyl acetate copolymer. 5. A styrene resin or a styrene resin composition having a gel amount of 0 to 20% by weight and a melt flow rate of 2%.
The thermoplastic resin laminate according to claim 1, wherein the weight is 20 g / 10 min. 6. A styrene resin or a styrene resin composition comprising 0-100% by weight of polystyrene having a weight average molecular weight of 200,000-400,000 and an average gel particle diameter of 0.1-5 μm.
The thermoplastic resin laminate according to claim 1, which is a styrene-based resin or a styrene-based resin composition containing 100 to 0% by weight of a rubber-modified polystyrene having a gel amount of 5 to 30% by weight. 7. The thermoplastic resin laminate according to claim 1, wherein the olefin resin or the olefin resin composition is a propylene resin or a propylene resin composition having a melt flow rate of 0.5 to 20 g / 10 minutes. .