JP2000079665A - Gas barrier synthetic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a synthetic resin foamed sheet excellent in moldability, rigidity or heat resistance and also excellent in steam and oxygen barrier properties. SOLUTION: A gas barrier synthetic resin foamed sheet wherein a gas barrier layer is provided on at least one surface of a foamed sheet base material comprising a resin compsn. containing 40-97 wt.% styrenic resin and 60-3 wt.% olefinic resin is excellent in moldability, rigidity, heat resistance, etc., by the action of the foamed sheet base material and excellent in steam and oxygen barrier properties by the action of the gas barrier layer. Therefore, this foamed sheet is suitable as a container material necessary for suppressing evaporation of moisture or oxidation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-barrier synthetic resin sheet and a gas-barrier synthetic resin foam sheet suitable as a molding material for various food containers, and to containers using these sheets.

[0002]

2. Description of the Related Art Styrene-based resins are widely used as container materials for various foods such as side dishes because of their excellent moldability and rigidity. Because of poor oil resistance, various techniques aiming at improving these properties have been proposed. As such a technique, for example, JP-A-6-25487 discloses a composition in which a styrene-based resin and a propylene-based resin are blended, and JP-A-4-288355 discloses a propylene-based polymer and a styrene-based resin. There is disclosed a composition in which a system polymer and a propylene-styrene copolymer are blended.

[0003] However, the characteristics required for food containers vary depending on the type of food, and it is sometimes not sufficient to have heat resistance and oil resistance. For example, from the viewpoint of preventing drying of the contents due to evaporation of moisture and oxidation of the contents due to permeation of oxygen, and preventing changes in taste, aroma, color, etc. of the food, in addition to heat resistance and oil resistance, Therefore, it is necessary to be able to suppress the passage of water vapor and oxygen.

An object of the present invention is to provide a gas-barrier synthetic resin sheet and a gas-barrier synthetic resin foam sheet which can prevent the passage of gases such as water vapor and oxygen. Another object of the present invention is to provide a container made of a gas-barrier synthetic resin sheet and a gas-barrier synthetic resin foam sheet.

[0005]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that a sheet obtained from a composition of a styrene resin and an olefin resin is used as a base material, and a gas barrier By forming a layer, it has been found that heat resistance and oil resistance can be improved without impairing the moldability and rigidity of the styrene resin, and that excellent gas barrier properties can be imparted, and the present invention has been completed.

That is, the present invention relates to (A) a styrene resin 40
A gas-barrier synthetic resin sheet having a gas-barrier layer on at least one surface of a sheet base comprising a resin composition containing the resin composition containing the olefin resin and the olefin resin in an amount of from 60 to 3% by weight. I will provide a. The present invention also provides
The foamed sheet base comprising a resin composition containing (A) 40 to 97% by weight of a styrene-based resin and (B) 60 to 3% by weight of an olefin-based resin has a gas barrier layer on at least one surface. To provide a gas barrier synthetic resin foam sheet. Further, the present invention provides a container made of a gas-barrier synthetic resin sheet or a gas-barrier synthetic resin foam sheet.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The gas-barrier synthetic resin sheet of the present invention is obtained by forming a gas-barrier layer on a sheet substrate.

The sheet substrate can be obtained by molding a resin composition containing a styrene resin as the component (A) and an olefin resin as the component (B). Examples of the styrene resin (A) used in the resin composition include a polymer of a styrene monomer and a copolymer of a styrene monomer and another monomer copolymerizable therewith.

As the styrene monomer, styrene,
Alkyl-substituted styrene such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-t-butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, α-methyl-4- One or more selected from α-alkyl-substituted styrene such as methylstyrene, halogenated styrene such as 2-chlorostyrene and 4-chlorostyrene, and the like can be given.

Other monomers copolymerizable with the styrene monomer include acrylic acid or methacrylic acid, methyl acrylate or methyl methacrylate, ethyl acrylate or ethyl methacrylate, butyl acrylate or butyl methacrylate, acrylic acid 2 Acrylic acid such as -ethylhexyl or 2-ethylhexyl methacrylate (C _1-
C ₈₎ esters or methacrylic acid (C ₁ ~C ₈₎ esters, acrylonitrile, maleic anhydride, maleimide,
One or more types selected from maleic acid or derivatives thereof such as N-substituted maleimide such as N-methylmaleimide and N-ethylmaleimide can be mentioned.

The styrene resin of the component (A) may be a rubber-modified styrene resin. Examples of the rubber used in the production of the rubber-modified styrene resin include non-styrene rubbers such as butadiene rubber, butadiene-isoprene rubber, butadiene-acrylonitrile rubber, ethylene-propylene rubber, isoprene rubber, acrylic rubber, and ethylene-vinyl acetate rubber; At least one selected from styrene rubbers such as butadiene rubber and styrene-isoprene rubber can be used. The butadiene rubber may be a high cis type having a high content of cis-1,4 structure or a low cis type having a low content of cis-1,4 structure. When the rubber-modified styrenic resin is used, the content of the rubber component in the resin is 1 to 2
It is preferably 0% by weight.

When the component (A) is formed into a copolymer, the polymerization form is not particularly limited, and a block copolymer,
It may be a random copolymer or a copolymer having a tapered block structure.

The content of the component (A) in the resin composition is from 40 to 97% by weight, preferably from 60 to 97% by weight.

Examples of the olefin resin (B) used in the resin composition include homopolymers of olefin monomers such as ethylene, propylene, and butylene, and other monomers copolymerizable with the olefin monomer and the olefin monomer. And copolymers thereof. Examples of the other monomer copolymerizable with the olefin monomer include the styrene monomer used in the component (A) and a monomer copolymerizable with the styrene monomer. As the component (B), polypropylene is preferable, and any of low density, medium density and high density polypropylene may be used.

The content of the component (B) in the resin composition is 60 to 3% by weight, preferably 40 to 3% by weight.
It is.

The resin composition may further contain one or more compatibilizers selected from the following (C-1) to (C-4) as component (C). When a component that also acts as a compatibilizing agent with the component (B) is used as the component (A), the compatibilizing can be sufficiently performed only by the action alone. There is no.

(C-1) A copolymer comprising a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof. Examples of the vinyl aromatic compound include monomers used in the component (A) described above, and examples of the conjugated diene compound include butadiene, chloroprene, and isoprene.

(C-2) An epoxidized product of a copolymer comprising a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof. Examples of the copolymer comprising a vinyl aromatic compound and a conjugated diene compound include a copolymer (C-1).

(C-3) A copolymer of a styrene monomer as a constituent unit of the component (A) and a monomer as a constituent unit of the component (B).

(C-4) A copolymer of a vinyl aromatic compound and a compound having a carboxyl group or an acid anhydride. Examples of the vinyl aromatic compound include the styrene-based monomer used in the component (A) described above, and examples of the compound having a carboxyl group and the acid anhydride are copolymerizable with the styrene-based monomer used in the component (A). Other monomers can be mentioned.

The compounding amount of the compatibilizer of the component (C) is (A)
And preferably 0.1 to 20 parts by weight, particularly preferably 2 to 5 parts by weight, based on 100 parts by weight of the total amount of component (B).
Parts by weight.

If necessary, a colorant such as a pigment, a dispersant such as a higher fatty acid salt, an inorganic filler such as talc, a conductivity-imparting agent, an antistatic agent, and silicone are added to the resin composition. be able to.

The sheet base material can be obtained by, for example, melting and kneading a pellet (resin pellet) made of a resin composition with a usual extruder, and then extruding the same through a circular die, a T die and the like.

The gas barrier synthetic resin sheet of the present invention comprises:
It can be manufactured by forming a gas barrier layer on one surface or both surfaces of a sheet substrate. The gas barrier layer can be formed on part or all of one surface of the sheet substrate.

As a method of forming the gas barrier layer, a method of coextruding a sheet base material and a resin having a gas barrier property, a method of laminating a resin film having a gas barrier property on a sheet base material, and the like are applied. Can be. Examples of the resin material for forming the gas barrier layer include one or more selected from polypropylene, saponified ethylene-vinyl acetate copolymer, polyamide resin, polyester resin, and polyacrylonitrile resin.

The gas barrier synthetic resin sheet of the present invention comprises:
It has the following characteristics (a) or (b) or (a) and (b).

(A) JIS K7126 (20 ° C., 80
% RH) per 0.6 mm of the laminated sheet (thickness of 0.1 mm).
The oxygen barrier property of the 6 mm gas-barrier synthetic resin sheet is 500 cc / m ² /24h/1013.25hPa or less. The oxygen barrier property is preferably 0.5~100cc / m ^2/24
h / 1013.25 hPa, particularly preferably 0.5 to 50 cc / h
m ² /24h/1013.25hPa.

(B) JIS K7129 (40 ° C., 90
% RH) per 0.6 mm of the laminated sheet (thickness of 0.1 mm).
The water vapor barrier property of a 6 mm gas barrier synthetic resin sheet is 100 g / m ² /24h/1013.25hPa or less. The water vapor barrier property is preferably 0.5~80g / m ^2/24
h / 1013.25 hPa, particularly preferably 0.5 to 40 g /
m ² /24h/1013.25hPa.

The gas barrier synthetic resin sheet of the present invention comprises:
A resin non-foamed sheet made of the same or different material may be laminated on one or both sides to form a laminate of two or more layers. The resin non-foamed sheet used in this case can be appropriately selected from desired materials in accordance with the intended use and properties to be imparted, for example, heat resistance, abrasion resistance, improvement in surface appearance, printability, and the like. . Known methods such as a co-extrusion method and a dry lamination method can be applied as a method for manufacturing the laminate. When applying the co-extrusion method, it is desirable to interpose an adhesive layer between the substrate and the gas barrier layer. Examples of the adhesive for forming the adhesive layer include known adhesives such as urethane resin-based adhesives, acrylic resin-based adhesives, and polyester resin-based adhesives. Urethane resin-based adhesives are preferred because of their strength.

The gas barrier synthetic resin foam sheet of the present invention is obtained by forming a gas barrier layer on a foam sheet substrate obtained by subjecting the above resin composition to foam molding. Examples of the foam molding method include a method of adding a chemical foaming agent and performing extrusion molding, a method of performing extrusion molding while injecting a foaming gas raw material, and a method of extruding a liquid foam gas raw material impregnated with a resin composition. Etc. can be applied. Examples of the chemical foaming agent and foam gas raw material include hydrocarbons such as sodium hydrogen carbonate, ammonium hydrogen carbonate, azodicarbonamide, azobisisobutyronitrile, liquid propane, and butane.

The gas-barrier synthetic resin foamed sheet of the present invention has the same numerical range as the gas-barrier synthetic resin sheet in the characteristics (a) or (b) of the gas-barrier synthetic resin sheet described above. .

The foamed gas-barrier synthetic resin sheet of the present invention preferably has at least one selected from the following requirements. Any one of these requirements may be provided, but it is particularly preferable that two or three requirements are provided, and it is more preferable that all four requirements are provided.

The surface gloss is preferably at least 10%, particularly preferably 1%, in order to keep the surface appearance beautiful after molding the container.
5% or more. When the surface gloss is 10% or more, the surface appearance does not deteriorate even when it is elongated during molding. The surface gloss is a value measured at an incident angle of 60 ° according to JIS K7105.

The expansion ratio is preferably 1.05 to 3.0.
And more preferably 1.4 to 2.2 times. When the expansion ratio is 1.05 times or more, heat retention, heat insulation, and appearance are good, and when the expansion ratio is 3 times or less, the container has good stacking properties and does not bulk.

The average number of cell membranes per unit thickness is preferably 1 to 50 / mm, particularly preferably 5 to 40 / mm. When the average number of cell membranes is 1 / mm or more, heat retention, heat insulation and appearance are good, and when the number is 50 / mm or less, the container has good stiffness and impact resistance.

The thickness is preferably 0.3 to 2.0 mm, particularly preferably 0.5 to 1.0 mm. The thickness is 0.
When it is 3 mm or more, the container has good stiffness and heat insulation, and when it is 2.0 mm or less, the container has good stacking properties and is not bulky.

The foamed gas-barrier synthetic resin sheet of the present invention can be formed into a laminate of two or more layers by laminating resin-non-foamed sheets made of the same or different materials on one or both surfaces. This laminate can be manufactured in the same manner as in the case of the laminate of the gas barrier synthetic resin sheet described above.

The gas-barrier synthetic resin sheet or the gas-barrier synthetic resin foam sheet of the present invention can enhance deep drawability and thin-wall moldability. Therefore, the sheet base of the resin sheet or the foam sheet of the resin foam sheet can be used. It is preferable that the component (A) and the component (B) form a bicontinuous phase in the substrate. Here, "the component (A) and the component (B) form a bicontinuous phase in the sheet substrate or the foamed sheet substrate" means that the sheet substrate or the foamed sheet substrate has an MD direction (sheet flow direction). In both the TD direction (the direction orthogonal to the MD direction), the styrene resin phase of the component (A) and the thermoplastic resin phase of the component (B) are independent of each other, such as particles or fibrous particles. This means that both phases form a mixed phase structure in a state where they are connected to each other in a network. When the gas-barrier synthetic resin sheet or the gas-barrier synthetic resin foam sheet of the present invention has such a bicontinuous structure, the volume change rate represented by the following formula (I) and the volume change rate represented by the following formula (II) Satisfying the relationship of the weight loss rate.

V ′ / V = 0.5 to 2.5 (I) [wherein V ′ represents the volume (cm ³ ) of the sheet after immersion in tetrahydrofuran at 25 ° C. for 24 hours, and V represents the volume before immersion. Indicates the volume (cm ³ ) of the sheet. (W−W ′) / W × n _PS ≧ 0.7 (II) wherein W ′ represents the weight (g) of the sheet after immersion in tetrahydrofuran at 25 ° C. for 24 hours, and W represents the weight before immersion. It shows the weight (g) of the sheet, and n _PS indicates the content ratio (% by weight) of the styrene resin in the sheet before immersion].

The resin sheet or foamed resin sheet having such a bicontinuous phase structure can be obtained by the above-described manufacturing method.
It can be obtained by adjusting so as to simultaneously satisfy the following three requirements. That is, the viscosity ratio of the component (A) to the component (B) is (A) / (B) = 1 or more, preferably (A) / (B) =
Adjust the screw speed in the extruder to 1 or more
00 rpm or less, preferably 40 to 80 rpm, and the melting temperature of the resin composition is 200 to 250 ° C., preferably 21 to
It can be obtained by adjusting the temperature to 0 to 240 ° C.

The container of the present invention is obtained by molding the above-mentioned gas-barrier synthetic resin sheet or the gas-barrier synthetic resin foam sheet into a desired shape. The term “container” as used in the present invention includes a main body and a lid. For example, a container for a side dish includes a tray and a lid. The container of the present invention is particularly suitable for applications in which evaporation of water is required to be suppressed or oxidation is required.
The present invention can be applied to a roux container such as curry, a yogurt container, a milk potion container for coffee, and the like.

[0042]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In addition, each test below was performed by the following method.

(Heat resistance of sheet) 3 g of salad oil (manufactured by Nisshin Oil Co., Ltd.) was applied to a sheet cut into a 10 cm square,
It was left in a thermostat at 00 ° C. for 2 minutes. Then, after allowing to cool to room temperature, the change in the sheet dimensions was measured, the degree of oil penetration was visually observed, and the heat resistance was evaluated according to the following criteria. The change in the sheet size was expressed as a percentage of the length and width of the sheet after heating and cooling to the original size. ：: Absolute value of dimensional change is less than 10%, and there is no oil seepage. Δ: The absolute value of the dimensional change is 10% or more and less than 20%,
Less than 50% of the total area was soaked with oil. ×: Absolute value of dimensional change is 20% or more, 5% of total area
Oil was soaked in 0% or more.

(Oxygen Barrier Property) Into this cup container shown in FIG. 1, cooked fresh broccoli (boiled broccoli in hot water for 3 minutes, chilled in ice water) was added. After fusing with the container opening to seal the cup container, it was placed in a refrigerated showcase and left at 4-7 ° C. for 7 days. Thereafter, the degree of discoloration of broccoli was visually observed and evaluated according to the following criteria. It should be noted that the smaller the degree of discoloration, the more the passage of oxygen was suppressed (the more discoloration due to oxidation was suppressed). ：: Bright green color was maintained. Δ: Discolored to whitish brown. X: Discolored to whitish brown and slick.

(Water Vapor Barrier Property) 200 g of water was placed in the cup container shown in FIG. 1, and the gas barrier synthetic resin sheet was fused to the container opening to seal the cup container.
After being left in a thermostat at 40 ° C. for 20 days, the amount of reduction (% by weight) of water was measured, and the water vapor barrier property was evaluated based on the following criteria. ：: less than 5% by weight of water. Δ: The decrease in water was 5% by weight or more and less than 10% by weight. X: The reduction of water is 10% by weight or more.

(Appearance of Cup Container) The appearance of the cup container shown in FIG. 1 was visually observed and evaluated according to the following criteria. ：: The surface is smooth and glossy. Δ: The surface is rough and there is no gloss. ×: The surface was extremely rough and rough when touched by hand.

(Cross Strength of Cup Container) Using a tensile tester (R-500) manufactured by Shimadzu Corporation, the cup container shown in FIG. 1 was compressed at a crosshead speed of 10 mm / min. The maximum buckling load was determined, and the strength of the waist was evaluated according to the following criteria. ：: 20 kgf or more. Δ: 15 kgf or more and less than 20 kgf. X: Less than 15 kgf.

(Impact resistance of cup container) 200 g of water was put into the cup shown in FIG. 1, dropped on a concrete surface from a predetermined height, and a height at which 50% or more of the container was cracked was determined. The impact properties were evaluated. ：: 50 cm or more. Δ: 10 cm or more and less than 50 cm. ×: less than 10 cm.

Examples 1 to 5 and Comparative Examples 1 to 4 A resin composition comprising the compatibilizers of the components (A), (B) and (C) having the compositions shown in Table 1 was prepared by the following method. A gas barrier synthetic resin sheet was produced. In Table 1,
The components (A) and (B) are expressed in weight%, and the component (C) is expressed in parts by weight based on the total amount of the components (A) and (B). The details of the component (A), the component (B), and the component (C) are as follows.

(A) Component GPPS: Styrene resin ("Daicel Styrol 51" manufactured by Daicel Chemical Industries, Ltd.) HIPS: High impact polystyrene resin ("Daicel Styrol S85" manufactured by Daicel Chemical Industries, Ltd.) Rubber content: 8 weight %) SBS: Styrene-butadiene block copolymer ("Taprene 126" manufactured by Asahi Kasei Corporation; rubber content: 60
(B) Component PP: Polypropylene (“F” manufactured by Grand Polymer Co., Ltd.)
219D ") HDPE: High-density polyethylene (" HIZEX "manufactured by Mitsui Chemicals, Inc.) (C) Component (compatibilizer) (C-3a): Styrene-ethylene-propylene-styrene copolymer (" Septon "manufactured by Kuraray Co., Ltd.) 2104 ”) (C-2a): Epoxy-modified styrene-butadiene copolymer (“ Epofriend A10 ”manufactured by Daicel Chemical Industries, Ltd.)
20 ") (C-2b): Hydrogenated epoxy-modified styrene-butadiene copolymer (JP-A-7-25984, page 2, column 2, 3)
(C-3b): Polypropylene-polystyrene graft copolymer (Nippon Oil & Fats Co., Ltd.) obtained by hydrogenating Epofriend A1020 manufactured by Daicel Chemical Industries, Ltd. by the method described in lines 1-43. "Modie Bar A310"
0 ") (C-3c): polycarbonate-polystyrene graft copolymer (" MODIVER CL15 "manufactured by NOF Corporation)
0D ") (C-4): Styrene-maleic anhydride copolymer (" Dailac 232 "manufactured by Arko Chemical Co., Ltd.) (Gas barrier film) Barrier film a: Unstretched polypropylene film (Toyobo Co., Ltd." Toyobo " Bilen film-CTP
1128 ") Barrier film b: saponified ethylene-vinyl acetate copolymer film (" 75R "manufactured by UCB Co., Ltd.) Barrier film c: nylon film (Toyobo Co., Ltd.)
Barrier film d: Biaxially stretched polyester film (Toyobo espppet film manufactured by Toyobo Co., Ltd.) (Gas barrier resin) Barrier resin a: Polypropylene (F219D manufactured by Grand Polymer Co., Ltd.) ) Barrier resin b: saponified ethylene-vinyl acetate copolymer (“EVAL” manufactured by Kuraray Co., Ltd.) Barrier resin c: nylon 6 (“10” manufactured by Ube Industries, Ltd.)
30B ") Barrier resin d: polyethylene terephthalate (" Dianight MA521H "manufactured by Mitsubishi Rayon Co., Ltd.).

First, such a resin composition is melt-kneaded by a twin-screw extruder (PCM30 / 2-28.5-2V manufactured by Ikegai Co., Ltd.), and then extruded in a strand shape, and cut into resin pellets. Obtained. Next, a gas-barrier synthetic resin sheet was obtained using a resin pellet and a gas-barrier film or gas-barrier resin. When a gas barrier film is used, the resin pellets are formed into a multilayer extruder (φ50 mm, φ30 mm,
φ20mm) extruder and φ20mm
An adhesive (ethylene-vinyl acetate copolymer; "Evert" manufactured by Sumitomo Chemical Co., Ltd.) is supplied to an extruder, and a gas barrier film is thermally laminated on a sheet substrate obtained by co-extrusion of the adhesive. Alternatively, they were obtained by lamination by hot melt lamination. When a gas barrier resin is used, the resin pellets are supplied to a φ50 mm extruder of a multilayer extruder, and the barrier resin is further supplied to a φ30 mm extruder to form a φ20 mm extruder.
Use an urethane resin-based adhesive (trade name Takerac A9)
71, manufactured by Takeda Pharmaceutical Co., Ltd.) and obtained by co-extrusion. A cup container as shown in FIG. 1 was formed from each of the thus obtained gas-barrier synthetic resin sheets using a single-shot vacuum forming machine manufactured by Asano Laboratories. The moldability of the container was as easy as the case of the sheet made of the styrene resin alone. Each test shown in Table 1 was performed on these gas barrier synthetic resin sheets and cup containers. Table 1 shows the results.

[0052]

[Table 1]

The gas barrier synthetic resin sheet of the example is
The moldability, rigidity and surface gloss were good, heat resistance and impact resistance were enhanced, and the water vapor barrier properties were also excellent. Example 1
The sheet substrates of Nos. 5 to 5 had a bicontinuous phase structure, and the sheet substrate of Comparative Example 1 had a sea-island structure in which polypropylene was a sea.

Examples 6 to 10, Comparative Examples 5 to 6 First, (A) of the composition shown in Table 2 (the same numerical value as in Table 1) was used.
Resin pellets were obtained in the same manner as in Examples 1 to 5, using a resin composition comprising the compatibilizer of the component, the component (B), and the component (C). One part by weight of mineral oil was spread on the resin pellet, and a mixture of sodium bicarbonate and sodium citrate (manufactured by Sankyo Chemical Co., Ltd .; CellMike 623) as a foaming agent was added in the amount (weight) shown in Table 1. Part) A mixed resin composition for a resin foam sheet was obtained. Using this resin composition, a gas-barrier synthetic resin foam sheet was obtained according to Examples 1 to 5. From each gas barrier synthetic resin sheet thus obtained, a cup container as shown in FIG. 1 was formed in the same manner as in Examples 1 to 5. The moldability of the container was as easy as the case of the foamed sheet made of the styrene resin alone. The same tests as in Examples 1 to 5 were performed on these gas barrier synthetic resin sheets and cup containers. Table 2 shows the results.

[0055]

[Table 2]

The gas-barrier synthetic resin foam sheet of the examples had good moldability, rigidity and surface gloss, improved heat resistance and impact resistance, and also had excellent water vapor barrier properties. The sheet substrates of Examples 6 to 10 had a bicontinuous phase structure, and the sheet substrate of Comparative Example 5 had a sea-island structure of polypropylene.

Examples 11 to 14, Comparative Example 7 The component (A) having the composition shown in Table 3 (same numerical value as in Table 1),
A gas barrier synthetic resin sheet was obtained in the same manner as in Examples 1 to 5, using a resin composition comprising the compatibilizers of the components (B) and (C). From each of the gas-barrier synthetic resin sheets obtained in this manner, as in Examples 1 to 5, FIG.
A cup container as shown in the following was molded. The moldability of the container is
It was easy as in the case of the sheet of the styrene resin alone. The same tests as in Examples 1 to 5 were performed on these gas barrier synthetic resin sheets and cup containers. Table 3 shows the results.

[0058]

[Table 3]

The gas barrier synthetic resin sheet of the example is
The moldability, rigidity and surface gloss were good, heat resistance and impact resistance were improved, and oxygen barrier properties were also excellent.

Examples 15 to 18, Comparative Example 8 The component (A) having the composition shown in Table 4 (the same numerical value as in Table 1),
A gas barrier synthetic resin foam sheet was obtained in the same manner as in Examples 6 to 10 using a resin composition comprising the compatibilizers of the components (B) and (C). From each gas barrier synthetic resin sheet thus obtained, a cup container as shown in FIG. 1 was formed in the same manner as in Examples 1 to 5. The moldability of the container was as easy as the case of the foamed sheet made of the styrene resin alone. The same tests as in Examples 1 to 5 were performed on these gas barrier synthetic resin sheets and cup containers. Table 4 shows the results.

[0061]

[Table 4]

The gas-barrier synthetic resin foam sheet of the examples had good moldability, rigidity and surface gloss, improved heat resistance and impact resistance, and also had excellent oxygen barrier properties.

[0063]

The gas-barrier synthetic resin sheet and the gas-barrier synthetic resin foam sheet of the present invention have good moldability, rigidity,
It has good surface gloss, excellent heat resistance and impact resistance, and also has excellent water vapor barrier properties and oxygen barrier properties.
Therefore, the container obtained from the gas-barrier synthetic resin sheet and the gas-barrier synthetic resin foam sheet of the present invention is suitable for applications in which evaporation and oxidation of moisture in the contents of the container need to be suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view and a front view of a cup container formed in an example.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 23/00 C08L 23/00 25/04 25/04 51/04 51/04

Claims (9)

[Claims] (A) 40 to 97% by weight of a styrene resin
And (B) a gas-barrier synthetic resin sheet having a gas-barrier layer on at least one surface of a sheet substrate made of a resin composition containing 60 to 3% by weight of an olefin-based resin. 2. The gas according to claim 1, wherein the resin composition further comprises at least one compatibilizer selected from the following (C-1) to (C-4) as the component (C). Barrier synthetic resin sheet. (C-1) a copolymer of a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof; (C-2) an epoxidized product of a copolymer of a vinyl aromatic compound and a conjugated diene compound; or (C-3) a copolymer of a styrene monomer serving as a constituent unit of the component (A) and a monomer serving as a constituent unit of the component (B), and (C-4) a vinyl aromatic compound. , A copolymer with a compound having a carboxyl group or an acid anhydride. 3. The gas-barrier synthetic resin sheet according to claim 1, which has the following characteristics (a) or (b). (A) 500 cc of oxygen barrier property per 0.6 mm of the laminated sheet according to JIS K7126 (20 ° C., 80% RH)
/ m ² /24h/1013.25hPa or less. (B) The water vapor barrier property per 0.6 mm of the laminated sheet according to JIS K7129 (40 ° C., 90% RH) is 100.
g / m ² /24h/1013.25hPa or less. 4. A container comprising the gas-barrier synthetic resin sheet according to claim 1, 2 or 3. 5. (A) 40 to 97% by weight of a styrene resin
And (B) a gas-barrier synthetic resin foam sheet having a gas barrier layer on at least one surface of a foam sheet substrate made of a resin composition containing 60 to 3% by weight of an olefin-based resin. 6. The resin composition further comprising at least one compatibilizer selected from (C-1) to (C-4) according to claim 2 as the component (C). 6. The gas barrier synthetic resin sheet according to item 5. 7. The gas-barrier synthetic resin sheet according to claim 5, which has the characteristics of (a) or (b) according to claim 3. 8. The gas barrier synthetic resin sheet has a surface gloss of 10% or more, an expansion ratio of 1.05 to 3.0 times, an average number of cell membranes per unit thickness of 1 to 50 / mm, and The gas-barrier synthetic resin sheet according to claim 5, which has one or more requirements selected from a thickness of 0.3 to 2.0 mm. 9. A container comprising the gas-barrier synthetic resin sheet according to any one of claims 5 to 8.