JPH0613631B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is a falling ball characterized by comprising a styrene polymer and a polyester elastomer, and the polyester elastomer comprising two or more polyester elastomers having different soft segments. The present invention relates to a thermoplastic resin composition having excellent impact strength, impact strength anisotropy, rib strength and chemical resistance.

<Prior Art> Styrene-based polymers typified by polystyrene and styrene-acrylonitrile copolymer have excellent mechanical properties, processability, and the like, and are used in many fields such as vehicle fields and weak electrical fields. There is. Further, conventionally, a method for improving the mechanical properties of these styrene-based polymers, particularly impact resistance, has been studied, and polybutadiene, ethylene / propylene copolymer, rubbery polymers such as polyacrylic acid ester,
High impact polystyrene (HIPS) obtained by graft-polymerizing compounds such as styrene and acrylonitrile,
Acrylonitrile-butadiene rubber-styrene (AB
S) and styrene polymers such as acrylonitrile-ethylene / propylene rubber-styrene (AES) are also put to practical use.

<Problems to be Solved by the Invention> However, the above-mentioned styrene-based polymer obtained by introducing a rubber-like polymer has impact resistance due to restrictions on graft polymerization,
At present, there is a limit to the balance between thermal stability and chemical resistance.

For example, when the amount of acrylonitrile in the graft polymer is increased in an attempt to improve chemical resistance, impact resistance, particularly falling ball impact strength, decreases, and at the same time, a copolymer having a high acrylonitrile content is produced as a by-product, resulting in thermal stability. In particular, there is a problem in that the stability of the molded product is poor when it stays in the molding machine and coloring of the molded product occurs.

Further, also in the styrene-acrylonitrile copolymer, when the acrylonitrile content is increased in order to improve the chemical resistance, there is a problem that the thermal stability and the processability are lowered as in the above graft polymer.

As a method for improving these problems, for example, Japanese Patent Laid-Open No.
0-1777037 gazette AES resin or AAS
A method of blending a saturated polyester resin with a resin (improvement in chemical resistance), AE described in JP-A-60-177039.
A method of blending S resin with a polyester elastomer (improvement of falling ball impact strength) has been proposed, and some improvement effect is recognized.

However, in recent years, with the decrease in the thickness of molded products, these resin compositions are still lacking in impact resistance, particularly falling ball impact strength, and new anisotropy and a new defect such as a marked decrease in rib strength of the molded product. Is occurring.

<Means for Solving Problems> The inventors of the present invention have earnestly studied to solve the above problems without sacrificing the excellent mechanical properties and processability which are the original features of styrene-based polymers. As a result, they have found that a composition comprising a styrene polymer and a specific polyester elastomer is a composition having excellent falling ball impact strength, anisotropy, rib strength and chemical resistance, and have reached the present invention. It is a thing.

The present invention will be described in detail below.

The styrene-based polymer (A) in the present invention, styrene,
It is a polymer containing an aromatic vinyl compound such as α-methylstyrene, p-methylstyrene, and chlorostyrene as an essential component, and is a homopolymer of an aromatic vinyl compound, and can be copolymerized with another aromatic vinyl compound. A copolymer consisting of a compound, a graft polymer obtained by polymerizing an aromatic vinyl compound alone or in combination with another copolymerizable compound in the presence of a rubbery polymer, and further a styrene polymer thereof (a homopolymer, It also means a mixture of a copolymer and a graft polymer).

The other copolymerizable compound constituting the above-mentioned copolymer or graft polymer, acrylonitrile, unsaturated nitrile compounds such as methacrylonitrile (i), methyl (meth) acrylate, ethyl (meth) acrylate, Unsaturated carboxylic acid alkyl ester such as butyl (meth) acrylate (ii), acrylic acid, methacrylic acid, maleic acid, maleic acid anhydride, unsaturated carboxylic acid such as citraconic acid anhydride or unsaturated dicarboxylic acid anhydride (iii) ),
Maleimide, methylmaleimide, ethylmaleimide, N
Examples thereof include maleimide compounds (iv) such as -phenylmaleimide and o-chloro-N-phenylmaleimide.

Specific examples of the copolymer include the following various copolymers. Styrene-acrylonitrile copolymer,
α-methylstyrene-acrylonitrile copolymer, styrene-methylmethacrylate copolymer, α-methylstyrene-acrylonitrile-methylmethacrylate copolymer, styrene-maleic anhydride copolymer, styrene-acrylonitrile-maleic anhydride copolymer Polymer, styrene-maleimide copolymer, styrene-N-phenylmaleimide copolymer, styrene-acrylonitrile-N-phenylmaleimide copolymer.

Further, as the rubbery polymer constituting the graft polymer,
Diene polymers such as polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer
(i), ethylene-propylene copolymers, ethylene-propylene-non-conjugated diene (ethylidene norbornene, dicyclopentadiene, etc.) copolymers and other ethylene-propylene polymers (ii), chlorinated polyethylene (iii), poly Examples thereof include acrylic rubber (iv) typified by butyl acrylate, ethylene-vinyl acetate copolymer (v), and the like.

Specific examples of the graft polymer include the following various graft polymers. Acrylonitrile-diene rubber-styrene polymer, methylmethacrylate-diene rubber-styrene polymer, acrylonitrile-ethylene-propylene rubber-styrene polymer, acrylonitrile-acrylic rubber-styrene polymer, acrylonitrile-chlorinated polyethylene- Styrene polymer, styrene-diene rubber-maleic anhydride polymer.

In the present invention, falling ball impact strength, anisotropy, rib strength,
From the viewpoint of not only chemical resistance but also the balance between processability and impact resistance, the styrene-based polymer is particularly a graft polymer or a mixture of the above-mentioned graft polymer and another homopolymer or copolymer. It is preferable.

These various styrene-based polymers can be produced by a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, or a combination thereof.

The graft polymerization of the graft polymer may be carried out in one step, or the multi-step graft polymerization may be carried out by changing the constituent components of the monomers.

In the thermoplastic resin composition of the present invention, two or more polyester elastomers having different soft segments are used.

Polyester elastomer is a block copolymer consisting essentially of a high-melting "hard segment" mainly composed of aromatic polyester and a "soft segment" having a relatively low molecular weight and low melting point. Depending on the type of soft segment, polyester-polyester It is roughly classified into ether type, polyester-polyester type and polyester-polylactone type.

The hard segment mainly composed of an aromatic polyester is a unit obtained from an acid component mainly composed of an aromatic dicarboxylic acid or an ester forming derivative thereof and a low molecular weight glycol having 2 to 10 carbon atoms or an ester forming derivative thereof, If necessary, a small amount of an aliphatic dicarboxylic acid having 2 to 32 carbon atoms, an alicyclic dicarboxylic acid, or an ester-forming derivative thereof may be used in combination. Further, the soft segment is an aliphatic polyether such as poly (alkylene oxide) glycol having a relatively low molecular weight, and having 2 to 2 carbon atoms.
Aliphatic polyesters and polylactones obtained from 32 aliphatic dicarboxylic acids, alicyclic dicarboxylic acids or their ester-forming derivatives and low molecular weight glycols having 2 to 10 carbon atoms or their ester-forming derivatives.

Examples of these constituents include terephthalic acid as an aromatic dicarboxylic acid or its ester-forming derivative,
Isophthalic acid, naphthalenedicarboxylic acid, dibenzoic acid,
Examples thereof include dicarboxybenzene sulfonic acid alkali metal salts and the like, or lower alkyl esters, cycloalkyl esters, aryl esters, hydroxyalkyl esters, acid halides and the like, and one kind or two or more kinds are used.

Examples of the low molecular weight glycol having 2 to 10 carbon atoms or its ester-forming derivative include ethylene glycol, propylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, neopentyl glycol, diethylene glycol, 2 2,2-bis (4-hydroxyphenyl) propane, p-xylylene glycol and the like can be mentioned, and one kind or two or more kinds are used.

Examples of the poly (alkylene oxide) glycol include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol and the like, or two kinds of alkylene oxide components such as ethylene oxide, propylene oxide and tetramethylene oxide. Examples thereof include random or block copolymers obtained by copolymerizing the above.

Examples of the aliphatic dicarboxylic acid having 2 to 32 carbon atoms, the alicyclic dicarboxylic acid or their ester-forming derivatives include adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, dimer acid and the like, or lower ones thereof. Examples thereof include alkyl esters, cycloalkyl esters, aryl esters, hydroxyalkyl esters, acid halides and the like, and one kind or two or more kinds are used.

Examples of the polylactone include poly ε-caprolactone, polyenant lactone, polycaprylolactone and the like, and random or block copolymers obtained by copolymerizing two or more kinds of ε-caprolactone, enanthlactone, caprylolactone and the like.

The composition ratio of the hard segment and the soft segment in the polyester elastomer is not particularly limited, but the hard segment is 20 to 95% by weight and the soft segment is 8
5 to 5% by weight is preferable.

These polyester elastomers can be produced by a known polycondensation method.

In the present invention, at least two polyester elastomers having different soft segments are essential.

If only one kind of polyester elastomer is mixed with the styrene-based polymer, a composition excellent in falling ball impact strength, impact strength anisotropy, rib strength and chemical resistance cannot be obtained with any of the polyester elastomers.

The resin composition of the present invention comprises a styrene polymer (A) 30-
96% by weight, an aromatic polyester in which the hard segment is an aromatic polyester, and an aromatic polyester in the soft segment is 2 to 68% by weight of an aliphatic polyether type polyester elastomer (B-1) and an aromatic polyester in the hard segment. And the soft segment is an aliphatic polyester: aromatic polyester-aliphatic polyester type polyester elastomer (B-
2) and / or the hard segment is an aromatic polyester, and the soft segment is a polylactone and comprises 2 to 68% by weight of an aromatic polyester-polylactone type polyester elastomer (B-3). Outside of this range, a composition having an excellent balance of physical properties such as falling ball impact strength, rib strength and chemical resistance cannot be obtained.

There is no limitation on the mixing order of the styrene-based polymer (A) and two or more polyester elastomers having different soft segments (B), as well as batch mixing, after mixing the styrene-based polymer and the polyester elastomer, Examples thereof include a method of further adding and mixing polyester elastomers having different soft segments, a method of mixing two or more kinds of polyester elastomers having different soft segments, and then further adding and mixing a styrene polymer.

For mixing and kneading, Banbury mixer, single-screw extruder,
It can be carried out by a known device such as a twin-screw extruder or a combination thereof.

Upon mixing, known additives such as antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, lubricants, plasticizers, dyes and pigments, as well as glass fibers, metal fibers, carbon fibers, potassium titanate, talc, carbonic acid. Reinforcing agents such as calcium, as well as fillers, polyvinyl chloride, ethylene-vinyl chloride copolymer, chlorinated polyethylene, ethylene-vinyl acetate copolymer, polymethylmethacrylate, thermoplastic polyester resin, polyamide, polyacetal, Other thermoplastic resins such as polycarbonate, polysulfone, and polyphenylene ether can be appropriately blended.

Examples will be described below, but the present invention is not limited thereto.

Examples <Production of styrene-based polymer (A)> A-1: Styrene-acrylonitrile copolymer By a known suspension polymerization method, 71% by weight of styrene, 29% by weight of acrylonitrile, and intrinsic viscosity (30 ° C, dimethylformamide). A copolymer of 0.65 was obtained.

A-2: α-methylstyrene-acrylonitrile copolymer By a known emulsion polymerization method, α-methylstyrene 75% by weight, acrylonitrile 25% by weight, intrinsic viscosity (30 ° C.,
A dimethylformamide) 0.48 copolymer was obtained.

A-3: Styrene-acrylonitrile-methylmethacrylate copolymer By a known suspension polymerization method, styrene 20% by weight, acrylonitrile 30% by weight, methylmethacrylate 50% by weight, intrinsic viscosity (30 ° C., dimethylformamide) 0.5.
A copolymer of 2 was obtained.

A-4: Styrene-maleic anhydride copolymer A copolymer having 87% by weight of styrene, 13% by weight of maleic anhydride and an intrinsic viscosity (30 ° C., dimethylformamide) of 0.58 was obtained by a known bulk polymerization method. .

A-5: Styrene-N-phenylmaleimide-acrylonitrile copolymer By a known emulsion polymerization method, 67% by weight of styrene, 10% by weight of N-phenylmaleimide, 23% by weight of acrylonitrile, intrinsic viscosity (30 ° C, dimethylformamide) 0.63.
A copolymer of

A-6: Acrylonitrile-Zinene rubber-Styrene polymer According to a known emulsion polymerization method, the weight average particle diameter is 0.43 μ,
100 parts by weight of polybutadiene rubber latex having a gel content of 85% by weight (solid content 50% by weight), 35 parts by weight of styrene and 15 parts by weight of acrylonitrile were graft-polymerized to obtain a polymer having a rubber content of about 50% by weight.

A-7: Acrylonitrile-ethylene-propylene rubber-styrene polymer By a known suspension polymerization method, propylene 50% by weight, ethylene number propylene having a iodine value of 15: 100 parts by weight ethylene-propylene-ethylidene norbornene, 70 parts by weight of styrene and 30 parts by weight of acrylonitrile. A part was graft-polymerized to obtain a polymer having a rubber content of about 50% by weight.

A-8: Acrylonitrile-acrylic rubber-styrene polymer By a known emulsion polymerization method, 94% by weight of butyl acrylate, 5% by weight of acrylonitrile and 1% by weight of ethylene glycol dimethacrylate were polymerized to obtain a weight average particle diameter of 0.23 μm. An alkyl acrylate rubber latex was obtained.

Next, 50 parts by weight of a monomer mixed solution consisting of 70% by weight of styrene, 20% by weight of acrylonitrile, and 0% by weight of methyl methacrylate was added to 50 parts by weight of solid content in the latex, and graft polymerization was carried out by a known emulsion polymerization method. A polymer having a rubber content of about 50% by weight was obtained.

A-9: Styrene-diene rubber-maleic anhydride polymer By a known bulk suspension polymerization method, 10% by weight of polybutadiene rubber with 75% by weight of gel, 75% by weight of styrene and 15% by weight of maleic anhydride were graft-polymerized. A polymer having a rubber content of about 10% by weight was obtained.

<Polyester Elastomer (B)> B-1: Polyester Elastomer in which Hard Segment is Aromatic Polyester and Soft Segment is Aliphatic Polyether Perprene P-40H and P-15 manufactured by Toyobo Co., Ltd.
0B B-2: Polyester elastomer in which the hard segment is an aromatic polyester and the soft segment is an aliphatic polyester Perprene S-3001 styrene polymers (A-1) to (A-9) manufactured by Toyobo Co., Ltd., a polyester elastomer (B -1) and / or (B-2) was mixed with a 40 mm extruder based on the compounding ratios shown in Tables 1-4.
The mixture was kneaded and granulated at 20 ° C to obtain the compositions shown in Tables 1 to 4.

Various test pieces were prepared from the obtained composition by an injection molding machine and used for evaluation. The test results are shown in Methods-1 to 4.

-Molding conditions-Toshiba machine injection molding machine IS-90B (5 ounces) Molding temperature: 240 ° C Mold temperature: 60 ° C Injection pressure: 100kg / cm ² (hydraulic pressure) Injection speed: 80% -Evaluation method-1) Falling ball Impact Strength A 150 × 90 × 3 mm molded product having a side gate with a thickness of 2.5 mm and a width of 4 mm in the center of the short side was molded under the above-mentioned molding conditions, and the impact strength at -30 ° C. was measured.

2) Anisotropy Izod impact test pieces were cut from the above-mentioned molded product in a direction parallel to the flow of the resin (MD) and a direction perpendicular to the direction (TD),
The notched Izod impact strength at 0 ° C was measured.

3) Rib strength 120 × 120 with a film gate with a thickness of 0.5 mm on one side and a thickness of 1.5 mm and a height of 10 mm over the entire length from the gate side to the non-gate side of the center of the molded product.
A molded product of × 3 mm was molded under the above-described molding conditions, three rib-strength test pieces with a width of 10 mm were cut from the gate side in parallel with the side having the gate, and one end of the test piece was fixed with an autograph chuck. . Attach the jig that hooks the rib root of the test piece to the other check of the autograph, 1
The rib breaking strength at 23 ° C. was measured at a speed of 0 mm / min, and the average value of three test pieces was shown.

4) Chemical resistance 150 × 20 × 3m from the above-mentioned molded product of 150 × 90 × 3mm
A test piece of m is cut out and a cantilever burr jig (Japanese Patent Laid-Open No. 58-4
5251 (see page 3), gasoline was applied, and after standing for 3 minutes, the distance (Xc) from the maximum deflection point to the crack initiation point was measured, and the critical strain (%) was calculated based on the following formula. It was

h: Thickness of test piece (3 mm) δ: Maximum deflection amount (30 mm) l: Distance from fixed end to maximum deflection point (100 mm) <Effect of the Invention> As is clear from the examples and comparative examples in Tables 1 to 4, the styrene-based polymer and the polyester elastomer,
A composition in which two or more kinds of polyester elastomers having different soft segments have excellent falling ball impact strength, anisotropy, rib strength and chemical resistance.

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Claims (3)

[Claims] 1. An aromatic polyester-aliphatic polyether type polyester elastomer (B-), wherein the styrene polymer (A) is 30 to 96% by weight, the hard segment is an aromatic polyester, and the soft segment is an aliphatic polyether. 1) Aromatic polyester-aliphatic polyester type polyester elastomer (B-2) in which 2 to 68% by weight and the hard segment is an aromatic polyester and the soft segment is an aliphatic polyester, and / or the hard segment is an aromatic polyester. A thermoplastic resin composition characterized by comprising 2 to 68% by weight of an aromatic polyester-polylactone type polyester elastomer (B-3) in which the soft segment is polylactone. 2. A graft polymer obtained by polymerizing an aromatic vinyl compound alone or an aromatic vinyl compound and another copolymerizable compound in the presence of a rubbery polymer, the styrene polymer (A), or The thermoplastic resin composition according to claim 1, which is a homopolymer of such a graft polymer and an aromatic vinyl compound or a mixture of a copolymer of an aromatic vinyl compound and another copolymerizable compound. . 3. The rubbery polymer is one or more polymers selected from a diene polymer, an ethylene-propylene polymer and an acrylic rubber, and the other copolymerizable compound is an unsaturated nitrile compound. The thermoplastic resin composition according to claim 2, which is one or more compounds selected from an unsaturated carboxylic acid alkyl ester, an unsaturated dicarboxylic acid anhydride, and a maleimide compound.