JP2001316558A - Rubber modified styrenic resin composition - Google Patents

Abstract

(57) [Problem] To provide a sheet excellent in water vapor barrier property, impact resistance, rigidity and heat resistance, and a container formed from the sheet. A (a ₁₎ and rubber-modified styrene resin,
(A ₂ ) a polystyrene resin, and the ratio (weight ratio) of the component (a ₁ ) to the component (a ₂ ) is (a ₁ ) /
(A ₂ ) = A styrene-based resin (A) and a cyclic polyolefin-based resin (B) having a ratio of 70/30 to 100/0,
The ratio (weight ratio) of the component (A) and the component (B) is
(A) / (B) = 80/20 to 50/50,
A resin composition is prepared and a sheet is formed with the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber-modified styrenic resin composition having excellent water vapor barrier properties, and more particularly to a rubber-modified styrenic resin composition used as a container for packaging foods and the like. The present invention relates to a formed sheet and a container formed from the sheet.

[0002]

2. Description of the Related Art A styrene resin sheet generally used for food packaging containers is formed by extruding a resin composition containing a styrene resin and a rubber-modified styrene resin having a salami-shaped rubber into an extruder. It is manufactured by. The styrene-based resin sheet has a good balance between the rigidity (elastic modulus) of the sheet and impact resistance, and is easy to mold a container. However, styrene resins have insufficient water vapor barrier properties and cannot be stored for a long period of time when filled with a liquid substance.

On the other hand, cyclic polyolefin resins have very high water vapor barrier properties. Further, the cyclic polyolefin-based resin has a glass transition temperature of about 60 to 160 ° C., and is excellent in container moldability because it is an amorphous resin.

However, cyclic polyolefin-based resins have poor impact resistance and poor compatibility with other resins. JP Hei 10
JP-A-111402 discloses a light-diffusing alloy sheet having a sea-island structure formed of a cyclic polyolefin-based resin and a transparent thermoplastic resin such as poly (4-methylpentene-1) or polycarbonate. However, this light diffusing alloy sheet is inferior in various physical properties such as impact resistance, rigidity and moldability since both resins are not compatible.

Japanese Patent Application Laid-Open No. 7-258504 discloses a polymer alloy sheet for packaging a highly moisture-resistant chemical, comprising 99 to 80% by weight of a cyclic polyolefin resin and 1 to 20% by weight of a styrene elastomer. JP 9
JP-A-1750 discloses a resin composition comprising 60 to 97.5% by weight of a polyolefin having a cyclic olefin component and 2.5 to 40% by weight of a styrene-based thermoplastic elastomer. There is disclosed a multilayer plastic container having an outer layer made of a resin layer containing 0.1% surfactant.

However, even the molded articles of these resin compositions have insufficient impact resistance. Further, since a large amount of a cyclic polyolefin-based resin, which is more expensive than a styrene-based resin, is used, it is not suitable for general-purpose applications such as food packaging containers.

[0007]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a rubber-modified styrenic resin composition having excellent water vapor barrier properties, a sheet formed from this composition, and a container formed from the sheet. It is in.

Another object of the present invention is to provide a rubber-modified styrene resin composition which is excellent in water vapor barrier properties and excellent in impact resistance even if the content of the cyclic polyolefin resin is small, and formed from this composition. And a container formed from the sheet.

Still another object of the present invention is to provide a rubber-modified styrenic resin composition having excellent rigidity, a sheet formed from the composition, and a container formed from the sheet.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a resin composition containing a rubber-modified styrene resin and a cyclic polyolefin resin has a water vapor barrier property and an impact resistance. The inventors have found that the present invention has excellent properties, and have completed the present invention.

That is, the resin composition of the present invention comprises (A)
Styrene resin and (B) cyclic polyolefin resin
A composition comprising (A) at least a rubber-modified component.
It is made of styrene resin. The component (A) comprises (a)
₁) A rubber-modified styrenic resin;_Two) Polystyrene
And (a)₁) Component and (a) _Two)
The ratio (weight ratio) to the components is (a₁) / (A_Two) = 50 /
It is about 50-100 / 0. (A) component and (B) component
(A) / (B) = 95 / 5−
40/60, preferably (A) / (B) = 95 / 5-5
It is about 0/50.

[0012] The present invention also includes a sheet formed from the resin composition. The present invention also includes a container formed of the sheet.

[0013]

DETAILED DESCRIPTION OF THE INVENTION [(A) Styrene resin] (A)
The component can be composed of at least (a ₁ ) a rubber-modified styrenic resin. The rubber-modified styrene-based resin is a polymer in which a rubber-like polymer is dispersed in a matrix composed of a polystyrene-based resin by copolymerization (graft polymerization, block polymerization, or the like) or the like. It is a graft copolymer obtained by polymerizing at least an aromatic vinyl monomer in the presence of coalescence by a conventional method (bulk polymerization, bulk suspension polymerization, solution polymerization, emulsion polymerization, etc.).

Examples of the aromatic vinyl monomer for forming the polystyrene resin include styrene, alkyl-substituted styrene (for example, vinyl toluene, vinyl xylene, p-ethyl styrene, p-isopropyl styrene,
Butylstyrene, pt-butylstyrene, etc.), halogen-substituted styrene (eg, chlorostyrene, bromostyrene, etc.), α-alkyl-substituted styrene having an alkyl group substituted at the α-position (eg, α-methylstyrene, etc.), and the like. Can be illustrated. These aromatic vinyl monomers can be used alone or in combination of two or more. Of these monomers, styrene, vinyltoluene, α-methylstyrene and the like, particularly styrene, are usually used.

The aromatic vinyl monomer may be used in combination with a copolymerizable monomer. Examples of the copolymerizable monomer include, for example, a vinyl cyanide monomer (eg, acrylonitrile), an unsaturated polycarboxylic acid or an acid anhydride thereof (eg, maleic acid, itaconic acid, citraconic acid or Acid anhydride), imide-based monomers [for example, maleimide, N-alkylmaleimide (for example,
N-C _1-4 alkylmaleimide, etc.), N-cycloalkylmaleimide (eg, N-cyclohexylmaleimide, etc.), N-arylmaleimide (eg, N-phenylmaleimide, etc.)], acrylic monomer [eg,
(Meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
_C1-20 alkyl (meth) acrylates such as hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) Hydroxy C _2-4 alkyl (meth) acrylates such as phenyl acrylate, benzyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate And the like]. These copolymerizable monomers are:
They can be used alone or in combination of two or more. The amount of the copolymerizable monomer in all the monomers is usually 1 to 50% by weight, preferably 3 to 40% by weight, more preferably 5 to 40% by weight.
It can be selected from a range of about 30% by weight.

As the rubbery polymer, for example, diene type
Rubber [Polybutadiene (low cis type or high cis type polybuta
Diene), polyisoprene, styrene-butadiene copolymer
Coal, styrene-isoprene copolymer, butadiene-a
Acrylonitrile copolymer, isobutylene-isoprene copolymer
Polymer, styrene-isobutylene-butadiene copolymer
Rubber, etc.], ethylene-vinyl acetate copolymer, acrylic resin
(Polyacrylic acid C _2-8Alkyl ester as main component
Copolymerized elastomer), ethylene-α-olefin
-Based copolymer [ethylene-propylene rubber (EPR)
Etc.], ethylene-α-olefin-polyene copolymer
[Ethylene-propylene-diene rubber (EPDM)
Etc.], urethane rubber, silicone rubber, butyl rubber, water
-Added diene rubber (hydrogenated styrene-butadiene copolymer)
, A hydrogenated butadiene-based polymer, etc.). What
The above copolymer is a random or block copolymer.
AB copolymers, ABA
Type, tapered type, and radial teleblock type structure
Copolymers and the like. These rubbery polymers are simply
They can be used alone or in combination of two or more. Preferred go
Polymer is a polymer of conjugated 1,3-diene or a derivative thereof.
Coalesce, especially diene rubber [polybutadiene (butadiene
Rubber), isoprene rubber, styrene-butadiene copolymer
Body etc.].

The content of the rubbery polymer is, for example, 3 to 8
It is about 0% by weight, preferably about 4 to 70% by weight, particularly preferably about 5 to 55% by weight (for example, about 6 to 60% by weight).

The form of the rubbery polymer dispersed in the matrix composed of the polystyrene resin is not particularly limited, and may be a core / shell structure, an onion structure, a salami structure, or the like. The particle size of the rubbery polymer constituting the disperse phase is, for example, a volume average particle size of 0.05 to 30 μm, preferably 0.1 to 10 μm, and more preferably 0.2 to 7 μm.
It can be selected from a range of about μm (particularly 0.5 to 5 μm). Further, the graft ratio of the rubbery polymer is 5 to 150.
%, Preferably about 10 to 150%.

Of these rubber-modified styrenic resins,
Impact polystyrene (HIPS), styrene-acrylonitrile-butadiene copolymer (ABS resin), α-
Methylstyrene-modified ABS resin, imide-modified ABS resin, MBS resin and the like are preferable, and HIPS is particularly preferable.

The weight average molecular weight of the polystyrene resin constituting the matrix of the rubber-modified styrene resin is 1
0.00-1,000,000, preferably 50,000
00 to 500,000, more preferably 100,00
It is about 0 to 500,000.

The component (A) may be composed of (a ₁ ) a rubber-modified styrenic resin alone, but in order to improve moldability, rigidity, etc., (a ₁ )
(A ₂ ) It is preferable that the composition is combined with a polystyrene resin. (A ₂ ) As the polystyrene resin,
A homopolymer or a copolymer of the aromatic vinyl monomer and a copolymer of the aromatic vinyl monomer and the copolymerizable monomer can be used. The proportion of the copolymerizable monomer in the copolymer can be used from the same range as described above. Among these (a ₂ ) polystyrene resins, from the viewpoint of compatibility with the rubber-modified styrene resin, polystyrene (GPPS), styrene-acrylonitrile copolymer (AS resin), styrene-methyl methacrylate copolymer, Styrene-maleic anhydride copolymer (SMA resin) and the like are preferred, and GPPS is particularly preferred.

The ratio (weight ratio) of the component (a ₁ ) to the component (a ₂ ) is (a ₁ ) / (a ₂ ) = 50 / 50-100 /
0, preferably about 60/40 to 100/0, and more preferably about 70/30 to 100/0.

Further, if necessary, an acrylic resin (for example, poly (meth) such as polymethyl methacrylate) may be used.
Alkyl acrylate, polyacrylonitrile,
Polyacrylamide, olefin resin (polyethylene, polypropylene, etc.), vinyl resin (vinyl chloride resin, vinylidene chloride resin, fluorine resin, vinyl acetate resin, ethylene-vinyl acetate copolymer, polyvinyl alcohol, ethylene- Vinyl alcohol copolymer, polyvinyl acetal, etc.), polyamide resin (nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 612, nylon 6/66, nylon 6/11 etc.), polyester resin (poly C _2-4 alkylene terephthalate, poly C _2-4 alkylene naphthalate, liquid crystalline polyester, etc.), polyacetal resin, thermoplastic polyurethane resin, polyether resin, polyketone resin, polyphenylene oxide resin, etc. You may.

[(B) Cyclic polyolefin resin] The cyclic polyolefin resin has a cyclic olefin unit in the main chain. Examples of the cyclic olefin include cycloalkylene, cycloalkenylene, cycloalkynylene, polycyclic olefin, and the like.

Examples of the cycloalkylene include C _3-10 cycloalkylene such as cyclopropylene, cyclobutylene, cyclopentene, cyclohexene and cyclooctene, and derivatives thereof.

Examples of cycloalkenylene include cyclopropenylene, cyclobutenylene, cyclopentenylene, cyclohexenylene, cyclooctenylene and the like.
Examples thereof include _3-10 cycloalkenylene and derivatives thereof.

Examples of the cycloalkynylene include, for example, cyclopropynylene, cyclobutynylene, cyclopentynylene, cyclohexynylene, cyclooctynylene and the like.
Examples thereof include _3-10 cycloalkynylene and derivatives thereof.

Examples of the polycyclic olefin include norbornene, dicyclopentadiene, dicycloheptadiene, tetracyclododecene, hexacycloheptadecene and derivatives thereof.

[0029] As the derivatives, include C _1-5 alkyl substituents, C _2-5 alkylidene substituents, C _1-5-alkoxy substituents, C _2-5 acyl substituents, halogen substituents, carboxyl substitution products are Can be

These cyclic olefins can be used alone or in combination of two or more.

The cyclic polyolefin resin may be a homopolymer of the cyclic olefin or a copolymer of a monomer copolymerizable with the cyclic olefin. Examples of the copolymerizable monomer include an olefin monomer and a vinyl monomer.

Examples of the olefin monomers include ethylene, propylene, allene, 1-butene, butadiene, 1-pentene, 1-hexene, 1-heptene,
Examples include linear C _2-10 olefins such as octene, and branched C _3-6 olefins such as isobutene and isoprene. Of these, linear C _2-6 olefins are preferred.

Examples of the vinyl monomers include vinyl esters, vinyl ethers, halogen-containing vinyl monomers, and (meth) acrylic monomers.

The vinyl esters include vinyl acetate,
And vinyl propionate. Examples of vinyl ethers include C _1-4 alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether.
Examples of the halogen-containing vinyl monomer include vinyl chloride and vinylidene chloride. (Meth) acrylic monomers include (meth) acrylic acid, (meth) acrylic acid esters (C _1-10 alkyl (meth) acrylates such as ethyl (meth) acrylate, hydroxyalkyl (meth) acrylate) , (Meth) glycidyl acrylate) and (meth) acrylonitrile.

These copolymerizable monomers can be used alone or in combination of two or more.

The ratio (molar ratio) of the cyclic olefin to the copolymerizable monomer is as follows: cyclic olefin / copolymerizable monomer = 100/0 to 10/90, preferably 80/20 to
20/80, more preferably 60 / 40-30 / 70
It is about.

Examples of the cyclic olefin homopolymer or copolymer include polymers represented by the following formulas (1) to (5):
Particularly, a polymer represented by the following formula (1) or (2) can be exemplified.

[0038]

Embedded image

(Wherein R ^{1 to} R ⁵ are the same or different,
Represents a hydrogen atom, a halogen atom, an alkyl group, an acyl group, an alkoxyl group, a carboxyl group or an alkylidene group, X represents an integer of 0 or more, and Y represents a natural number.) The glass transition temperature of the cyclic polyolefin resin is 60 to
It is about 160 ° C., and can be appropriately selected from this range according to the use and the molding temperature.

The melt flow rate of the cyclic polyolefin resin at the time of melting is 260 ° C. under a load of 2.16 kg.
It can be selected from the range of 50 g / 10 min, preferably 10 to 40 g / 10 min.

The ratio (weight ratio) of component (A) to component (B) is (A) / (B) = 95/5 to 40/60, preferably (A) / (B) = 95/5. To 50/50 (for example, 90/10 to 50/50), more preferably (A) / (B) = 80/20 to 50/50 (for example, 7
5/25 to 50/50).

[Resin Composition] The resin composition of the present invention comprises:
It may be a mixture of powders of the components (A) and (B), or may be prepared by kneading the components (A) and (B).
For the kneading, a conventional method can be used. For example, each component is dry-mixed with a Henschel mixer or a ribbon mixer, and a conventional melt mixing such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, a mixing roll, or the like is used. It can be supplied to the machine and melt-kneaded. Styrene resin composition,
It may be in the form of a pellet.

A coloring agent, if necessary, may be added to the resin composition.
Dispersants, release agents, stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), flame retardants, lubricants, fillers, antistatic agents and the like may be added.

The resin composition of the present invention contains a white colorant (for example, calcium carbonate, titanium oxide (titanium white), zinc oxide, zinc sulfide, lithopone, etc.) in order to enhance the hygiene.
In particular, titanium oxide may be added. The white colorant may be used in an amount of 1 to 30 parts by weight, preferably about 3 to 15 parts by weight, per 100 parts by weight of the total of the components (A) and (B). Further, a blue colorant, a green colorant, a black colorant and the like may be used together with the white colorant.

[Molding Method] The resin composition is excellent in moldability. The method for producing the resin sheet is not particularly limited,
The resin composition can be supplied to a usual extruder, melt-kneaded, extruded from a die (flat, T-shaped (T-die), cylindrical (circular die), etc.) and molded. The sheet may be stretched (uniaxially stretched, biaxially stretched, or the like), or may be an unstretched sheet that has a draw (drawing) applied in the extrusion direction. If necessary, a blowing agent (chemical blowing agent or gas)
May be foamed and extruded.

The sheet may be a single-layer sheet or a laminated sheet composed of a plurality of layers.
The laminated sheet may be a laminated sheet in which a layer composed of the resin composition of the present invention is formed on at least one surface layer or inner layer. Examples of such a laminated sheet include a laminated sheet having a two-layer structure, a laminated sheet having two and three layers, and a laminated sheet having three and five layers. The material of the laminated sheet is not particularly limited as long as the formability and impact resistance are not impaired. For example, a resin layer formed of a styrene resin of the same type as the component (A) or a cyclic polyolefin of the same type as the component (B) It may be a laminated sheet of a resin layer formed of a base resin and a resin layer formed of the resin composition of the present invention.

The laminated sheet can be prepared by a method such as coextrusion, heat lamination or dry lamination, and does not necessarily require an adhesive.

The thickness of the entire resin sheet is 0.1 to 3 m
m, preferably 0.1 to 2.5 mm (for example, 0.1 to 2.5 mm)
2 mm), and more preferably about 0.2 to 1.5 mm (for example, 0.2 to 1 mm).

The sheet obtained in this way can be subjected to secondary forming by, for example, conventional thermoforming such as free blow molding, vacuum forming, bending, pressure forming, match mold forming, hot plate forming and the like. .

The resin composition and sheet of the present invention have high gas barrier properties (particularly, water vapor barrier properties). Also, it has excellent impact resistance, rigidity, heat resistance and moldability. Therefore, it can be used for various purposes, for example, as a secondary molded article such as a container. Examples of the container include a container for filling a liquid such as a beverage, a container for food, a container for medicine, a container for an oven or a microwave oven, a container of a type in which boiling water is poured (for example, a container for instant food, etc.), a food containing fats and oils (for example, In addition to oil-and-fat-containing foods such as gyoza, foods such as fish and shellfish from which oils and fats ooze, etc.), containers used for heat sterilization, and non-heated containers. The container may include not only a container body having a concave portion for accommodating the container, but also a lid. The lid may be removable or hingedly connected to the container body as long as it can be opened and closed. The lid may be formed of a sealant made of a metal foil having high gas barrier properties.

Further, since the container of the present invention has particularly excellent water vapor barrier properties, it can be preferably used as a container for sealing and filling a liquid or gel-like substance (eg, a milk portion container). .

[0052]

According to the present invention, it is possible to obtain a rubber-modified styrenic resin composition having excellent water vapor barrier properties and excellent impact resistance and rigidity. This resin composition has high moldability and is useful for obtaining a sheet for molding a container or the like.

[0053]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, the evaluation method of each evaluation item in an Example, and the content of each component used are as follows.

[Tensile Modulus] Using a tensile tester, JI
MD direction and TD of the sheet according to S K 7127
The tensile modulus in the direction was measured.

[Water vapor barrier property] JIS K 7129
The water vapor barrier property of the sheet (0.8 mm thick) under the conditions of 40 ° C. and 90% RH was measured in accordance with the above.

[Abbreviations and Details of Each Component] HIPS: Daicel Styrol S85 GPPS manufactured by Daicel Chemical Industries, Ltd. Daicel Styrol 31N manufactured by Daicel Chemical Industries, Ltd. Cyclic PO-1: Addition polymer of norbornene (Mitsui Chemicals, Inc.) Apel APL6509, glass transition temperature 80
C) Cyclic PO-2: Ring-opening polymer of norbornene (manufactured by Zeon Corporation, Zeonoa 1420, glass transition temperature 140)
° C) PP: Polypropylene (Grand Polymer Co., Ltd., B
101WA)

Examples 1-4 and Comparative Examples 1-2 After the components were dry-blended using a tumbler at the ratios shown in Table 1, a single-screw extruder (L / D = 3) having a diameter of 65 mm was used.
After melt-kneading at a cylinder temperature of 210 ° C according to 2), the mixture was extruded from a T-die into a sheet at a die temperature of 210 ° C. The sheet was cooled by a cooling roll to produce a sheet having a thickness of about 0.8 mm. Table 1 shows the evaluation results of the obtained sheets.

[0058]

[Table 1]

According to the results shown in Table 1, in Examples 1 to 4, rigidity and water vapor barrier properties were excellent, but in Comparative Examples 1 and 2,
Poor water vapor barrier properties.

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[Procedure amendment]

[Submission date] September 6, 2000 (2000.9.6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0058

[Correction method] Change

[Correction contents]

[0058]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 45/00 C08L 45/00 51/06 51/06 51/08 51/08 55/02 55/02 F Terms (reference) 3E067 AB01 AB26 AB81 BA20A BB15A BB25A CA04 CA17 FA01 FC01 3E086 AB01 AD01 AD05 AD06 BA02 BA04 BA15 BB02 CA01 4F071 AA22 AA39 AA77 AF07 AH05 BC01 4J002 BC04X BK00Y BN03W BN14WBN

Claims (6)

[Claims] 1. A resin composition comprising (A) a styrene-based resin and (B) a cyclic polyolefin-based resin, wherein the component (A) comprises at least a rubber-modified styrene-based resin. 2. The component (A) is composed of (a ₁ ) a rubber-modified styrenic resin and (a ₂ ) a polystyrene resin, and a ratio (weight) of the (a ₁ ) component to the (a ₂ ) component. Ratio),
_{(A 1) / (a 2} ) = 50 / 50~100 / 0 a is claim 1 resin composition. 3. The resin composition according to claim 1, wherein the ratio (weight ratio) of the component (A) to the component (B) is (A) / (B) = 95/5 to 40/60. 4. The resin composition according to claim 1, wherein the ratio (weight ratio) of the component (A) to the component (B) is (A) / (B) = 95/5 to 50/50. 5. A sheet formed from the resin composition according to claim 1. 6. A container formed from the sheet according to claim 5.