JP2002088211A - Method for producing thermoplastic resin composition molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a thermoplastic resin composition molding which comprises a thermoplastic resin composition containing a syndiotactic alkenylaromatic resin and a polyphenylene ether resin and/or a non-syndiotactic alkenylaromatic resin and is excellent in chemical resistance and external appearance. SOLUTION: This molding is produced from a thermoplastic resin composition containing (A) a syndiotactic allcenylaromatic resin and (B) a polyphenylene ether resin and/or a non-syndiotactic alkenylaromatic resin in a wt. ratio of ingredient A to ingredient B of (1/99)-(60/40) under the conditions satisfying the equation: Tma>Tf>=[Tma- (Tma-Tg)/3}] (wherein Tf is the molding temperature; Tma is the melting point of ingredient A; and Tg is the glass transition point of the composition).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a molded article of a thermoplastic resin composition. More specifically, the present invention comprises a thermoplastic resin composition containing an alkenyl aromatic resin having a syndiotactic structure and a polyphenylene ether resin and / or an alkenyl aromatic resin having no syndiotactic structure, The present invention relates to a method for producing a molded article of a thermoplastic resin composition having excellent chemical resistance and excellent appearance.

[0002]

2. Description of the Related Art Amorphous resins such as polyphenylene ether resins and alkenyl aromatic resins having no syndiotactic structure have excellent dimensional stability and the like, and are excellent in terms of shape stability of molded articles. However, since it has low resistance to chemicals such as organic solvents, various oils, and detergents, it is not suitable for applications requiring chemical resistance. Japanese Patent Application Laid-Open No. 02-64140 discloses a technique for adding an alkenyl aromatic resin having a syndiotactic structure to a polyphenylene ether-based resin in order to compensate for this drawback. However, simply adding a polyphenylene ether-based resin does not easily crystallize an alkenyl aromatic-based resin having a syndiotactic structure, and cannot improve chemical resistance.
In order to solve such a problem, the mold temperature at the time of injection molding must be equal to or higher than (glass transition temperature of alkenyl aromatic resin having a syndiotactic structure −10 ° C.) (melting of alkenyl aromatic resin having a syndiotactic structure). Temperature +
Japanese Patent Application Laid-Open No. H11-11010)
Although disclosed in Japanese Patent No. 5236, the degree of crystallization cannot be sufficiently increased, and the effect of improving solvent resistance is small. Further, when the temperature of the mold during injection molding is high, there is a drawback that the cooling time until the molded product is taken out is prolonged and productivity is deteriorated.

[0003]

In view of such circumstances, an object of the present invention is to provide an alkenyl aromatic resin having a syndiotactic structure and a polyphenylene ether-based resin and / or having a syndiotactic structure. Another object of the present invention is to provide a method for producing a molded article of a thermoplastic resin composition comprising a thermoplastic resin composition containing a non-alkenyl aromatic resin and having excellent chemical resistance and excellent appearance.

[0004]

That is, the present invention comprises the following components (A) and (B) at a weight ratio of (A) / (B) of 1/99 to 60/40. The present invention relates to a method for producing a molded article made of a thermoplastic resin composition, wherein the molded article is molded under the condition of the following formula (1). (A): alkenyl aromatic resin having a syndiotactic structure (B): polyphenylene ether resin and / or alkenyl aromatic resin having no syndiotactic structure Tma> Tf ≧ [Tma-{(Tma- Tg) / 3}] (1) Here, Tf represents a molding temperature, Tma represents a melting temperature of the component (A), and Tg represents a glass transition temperature of the thermoplastic resin composition.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The component (A) is an alkenyl aromatic resin having a syndiotactic structure. A syndiotactic structure is a syndiotactic structure in which a phenyl group or a substituted phenyl group, which is a side chain with respect to a main chain formed from carbon-carbon bonds, is alternately located in the opposite direction. Its tacticity is determined by nuclear magnetic resonance ( ¹³ C)
-NMR method). ^The tacticity measured by the ¹³ C-NMR method is determined by the ratio of the presence of a plurality of continuous structural units, for example, dyad,
In the case of styrene-based polymer having a syndiotactic structure, it is usually 75% or more, preferably 85% by racemic diad. Or polystyrene having a syndiotacticity of 30% or more, preferably 50% or more in racemic pentad,
Poly (alkyl styrene), poly (halogenated styrene), poly (halogenated alkyl styrene), poly (alkoxy styrene), poly (vinyl benzoate), their hydrogenated polymers and their mixtures, or mainly A copolymer as a component is referred to. In addition,
Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tertiary-butylstyrene), poly (phenylstyrene), poly (vinylnaphthalene), poly (vinylnaphthalene) Vinyl (styrene), and poly (halogenated styrene) includes poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like. Also, as poly (halogenated alkylstyrene), poly (chloromethylstyrene)
Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

Particularly preferred alkenyl aromatic resins as component (A) include polystyrene and poly (p-
Methylstyrene), poly (m-methylstyrene), poly (p-tert-butylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p
-Fluorostyrene) and copolymers containing these structural units. In addition, the said styrene-type polymer can be used individually by 1 type or in combination of 2 or more types.

The component (A) is described in, for example, JP-A-62-18
As described in JP-A-7708, an alkenyl aromatic monomer is polymerized in an inert hydrocarbon solvent or in the absence of a solvent using a titanium compound and a condensation product of water and a trialkylaluminum as a catalyst. Can be manufactured.

The component (B) of the present invention is a polyphenylene ether resin and / or an alkenyl aromatic resin having no syndiotactic structure. As the polyphenylene ether-based resin, the following general formula (wherein, R ₁ , R ₂ ,
R ₃ , R ₄ and R ₅ are each selected from a hydrogen atom, a halogen atom, a hydrocarbon group or a substituted hydrocarbon group, and one of them is always a hydrogen atom. ) Is a (co) polymer obtained by oxidatively polymerizing one or more of the phenolic compounds represented by the formula (2) with oxygen or an oxygen-containing gas using an oxidation coupling catalyst.

Specific examples of R ₁ , R ₂ , R ₃ , R ₄ and R _{5 in} the above general formula include hydrogen, chlorine, bromine, fluorine,
Iodine, methyl, ethyl, n- or iso-propyl,
pri-, sec- or t-butyl, chloroethyl, hydroxyethyl, phenylethyl, benzyl, hydroxymethyl, carboxyethyl, methoxycarbonylethyl, cyanoethyl, phenyl, chlorophenyl, methylphenyl, dimethylphenyl, ethylphenyl, allyl, etc. . Specific examples of the above general formula include phenol, o-, m- or p-cresol, 2,6-,
2,5-, 2,4- or 3,5-dimethylphenol,
2-methyl-6-phenylphenol, 2,6-diphenylphenol, 2,6-diethylphenol, 2-methyl-6-ethylphenol, 2,3,5-, 2,3
6- or 2,4,6-trimethylphenol, 3-methyl-6-t-butylphenol, thymol, 2-methyl-6-allylphenol and the like. Furthermore, a phenolic compound other than the above general formula, for example, a polyhydric hydroxyaromatic compound such as bisphenol-A, tetrabromobisphenol-A, resorcin, hydroquinone, and a novolak resin, and a phenolic compound represented by the above general formula are used. It may be used as a raw material for a polymer. Among these compounds, 2,6-dimethylphenol, 2,6-dimethylphenol
Diphenylphenol, 3-methyl-6-t-butylphenol and 2,3,6-trimethylphenol are preferred.

The oxidative coupling catalyst used in the oxidative polymerization of the phenol compound is not particularly limited, and any catalyst having a polymerization ability can be used. The method for producing such a polyphenylene ether-based resin is as follows:
For example, U.S. Pat.
Nos. 6875 and 3257357, JP-B-52-17880, JP-A-50-51197, JP-A-1-304119 and the like.

Specific examples of the polyphenylene ether resin in the present invention include poly (2,6-dimethyl-1,1)
4-phenylene ether), poly (2,6-diethyl-
1,4-phenylene ether), poly (2-methyl-6)
-Ethyl-1,4-phenylene ether), poly (2-
Methyl-6-propyl-1,4-phenylene ether), poly (2,6-dipropyl-1,4-phenylene ether), poly (2-ethyl-6-propyl-1,4)
-Phenylene ether), poly (2,6-butyl-1,1)
4- (phenylene ether), poly (2,6-dipropenyl-1,4-phenylene ether), poly (2,6-dilauryl-1,4-phenylene ether), poly (2
6-diphenyl-1,4-phenylene ether), poly (2,6-dimethoxy-1,4-phenylene ether), poly (2,6-diethoxy-1,4-phenylene ether), poly (2-methoxy- 6-ethoxy-1,
4-phenylene ether), poly (2-ethyl-6-stearyloxy-1,4-phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2-methyl-1) , 4-phenylene ether), poly (2-ethoxy-1,4-phenylene ether), poly (2-chloro-1,4-phenylene ether), poly (3-methyl-6-t-butyl-1,4) -Phenylene ether), poly (2,6-dichloro-1,4)
-Phenylene ether), poly (2,5-dibromo-)
Examples thereof include 1,4-phenylene ether), poly (2,6-dibenzyl-1,4-phenylene ether), and various copolymers containing a plurality of repeating units constituting these polymers. Some copolymers include 2,3,6-
Copolymers of polysubstituted phenols such as trimethylphenol and 2,3,5,6-tetramethylphenol and 2,6-dimethylphenol are also included. Preferred among these polyphenylene ether resins are poly (2,6-
Dimethyl-1,4-phenylene ether) and 2,6-
It is a copolymer of dimethylphenol and 2,3,6-trimethylphenol.

Although the preferred range of the molecular weight of the polyphenylene ether-based resin that can be used in the present invention varies depending on the purpose, the range is not generally defined.
Generally 0.1 to 0.7 dl / g, preferably 0.3 to 0.3 dl / g, expressed as intrinsic viscosity measured in chloroform at 30 ° C.
0.6 dl / g.

The polyphenylene ether resin used in the present invention is styrene, α-
A copolymer modified by grafting a styrene compound such as methylstyrene, p-methylstyrene, vinyltoluene and chlorostyrene may be used.

An alkenyl aromatic resin having no syndiotactic structure is a homopolymer of an alkenyl aromatic compound produced by ordinary radical polymerization or the like or a monomer copolymerizable with the alkenyl aromatic compound. And the like. Examples of the alkenyl aromatic compound include styrene, α-methylstyrene, α-ethylstyrene, α-methylstyrene-p-methylstyrene, o
-Nucleated alkyl-substituted styrene such as -methylstyrene, m-methylstyrene, p-methylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-
Examples thereof include halogenated styrenes such as bromostyrene, dichlorostyrene, dibromostyrene, trichlorostyrene, and tribromostyrene. Among them, styrene and α-methylstyrene are preferable.

Examples of the monomer copolymerizable with the vinyl aromatic compound include, for example, vinyl cyanide such as acrylonitrile, methacrylonitrile, fumaronitrile, and maleonitrile; methyl methacrylate, methyl acrylate, methacrylic acid; Acrylic acid, maleic anhydride and the like can be mentioned, and among them, acrylonitrile is preferable.

Further, rubber-modified high impact polystyrene (HIPS) comprising 70 to 99% by weight of the above alkenyl aromatic resin and 1 to 30% by weight of diene rubber can be used. Examples of the diene rubber constituting HIPS include homopolymers of conjugated diene compounds such as butadiene, isoprene and chloroprene, copolymers of conjugated diene compounds and unsaturated nitrile compounds or aromatic vinyl compounds, and also natural rubber. And one or more of these can be used. In particular, polybutadiene and a butadiene-styrene copolymer are preferred. HIP
S is emulsion polymerization, suspension polymerization, bulk polymerization, solution polymerization, or
It is obtained by a method of their combination.

The thermoplastic resin composition of the present invention comprises (A) and (B) in a weight ratio of (A) / (B) of from 1/99 to 60 /
40, preferably 3/97
４０40/60. If (A) is too small, the effect of improving chemical resistance is poor. on the other hand,
When (A) is excessive, heat resistance is deteriorated.

The thermoplastic resin composition of the present invention may contain dyes, pigments, antistatic agents, lubricants, antioxidants, weathering agents and the like. Further, the thermoplastic resin composition of the present invention may contain an inorganic filler such as calcium silicate, magnesium silicate, glass fiber, metal whisker, silica, calcium carbonate, wollastonite, talc, mica, and kaolin.

The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and examples thereof include various methods such as a solution blending method and a melt kneading method. Among these, the melt kneading method is preferred. As a specific method, a method in which each component is melt-kneaded with a known kneading machine such as a Banbury mixer, a plast mill, a Brabender, or a single-screw or twin-screw extruder can be exemplified. In kneading, the kneading temperature is usually 1
A range of 50 to 400C, preferably 200 to 350C is selected.

The method for producing a molded article of the thermoplastic resin composition of the present invention is characterized in that the molded article is molded under the condition of the following formula (1). Tma> Tf ≧ [Tma-{(Tma−Tg) / 3}] (1) where Tf represents a molding temperature, Tma represents a melting temperature of the component (A), and Tg is a glass of the thermoplastic resin composition. Represents the transition temperature.

When the molding method is injection molding or extrusion molding, Tf corresponds to the cylinder temperature of the injection molding machine or extruder. Generally, the cylinder temperature can be set for each of a plurality of zones.
It is necessary to set the above region to the temperature range of the above equation (1). When the molding method is press molding, Tf corresponds to the temperature of the press die, and it is necessary to substantially keep the entire surface within the temperature range of the above formula (1). When the molding method is calender molding, Tf corresponds to the set temperature of the calender roll.
In calendering, generally three or more calender rolls are used, but it is necessary that the number of rolls equal to or more than 1/2 be within the temperature range of the above formula (1).

The molding method used for producing the molded article of the thermoplastic resin composition of the present invention is not limited to the above-mentioned molding method. It is necessary to set the temperature of a region of at least half of the flow path to the temperature range of the above formula (1), and in the case of a molding method that does not involve the flow of the resin outside the inside of the mold, the metal contacted with the molten resin The temperature of the mold part is calculated by the above equation (1).
It is necessary to set the temperature range.

When Tf is higher than Tma, crystallization of component (A) does not proceed sufficiently, and the effect of improving chemical resistance is poor. Further, when Tf is [Tma-{(Tma-Tg)
/ 3}]], the fluidity of the resin composition is poor, the appearance of the molded product is deteriorated, and molding becomes difficult. That is, by adopting the condition of the above formula (1) of the present invention, crystallization of the component (A) is promoted, chemical resistance is improved, and a molded article having a good appearance can be obtained. .

The molded article of the present invention is used in fields where chemical resistance is required, for example, electric and electronic parts such as flyback transformers and deflection yokes, peripheral parts such as microwave ovens, and the like.
For water supply / drainage / supply / exhaust parts such as pumps, tanks, ducts, etc.
It can be used for battery cases and other battery cases, tap water dispensers, developing tanks, fans and fan housings. In addition, automotive applications such as instrument panels, wheel covers, fuse holders, radiator grills, ignition coils, side mudguards, bumpers, etc., housings for OA equipment, chassis for OA equipment,
It can be used for mechanical parts such as trays and coin mechanical chassis of vending machines.

[0025]

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. The meanings of the abbreviations used in Examples and Comparative Examples are shown below. Component (A): Alkenyl aromatic resin having SPS syndiotactic structure Trademark “XAREC 130ZC” (made by Idemitsu Petrochemical Co., Ltd.)
Melting point: 272 ° C. Component (B): PPE polyphenylene ether resin Resin having an intrinsic viscosity of 0.3 in a chloroform solvent at 30 ° C.
40 dl / g poly (2.6-dimethyl-1,4-phenylene ether) (B) Component: Alkenyl aromatic resin having no APS syndiotactic structure Trademark “Sumibrite H5”
54 "(manufactured by Nippon Polystyrene Co., Ltd.) High impact polystyrene

Reference Example 1: Preparation of thermoplastic resin composition 1 10% by weight of PPE, 20% by weight of SPS, and 70% by weight of APS were mixed with a twin-screw kneader TEM50A (manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 280.degree. Number 200
After melt-kneading under the condition of rpm and extruding from the die,
The mixture was cooled in a water tank and pelletized with a strand cutter to obtain a thermoplastic resin composition 1.

Reference Example 2 Preparation of Thermoplastic Resin Composition 2 A thermoplastic resin composition 2 was obtained in the same manner as in Reference Example 1, except that PPE was 30% by weight, SPS was 20% by weight, and APS was 50% by weight.

Glass transition of continuous phase of thermoplastic resin composition
Measurement method of temperature Use a differential scanning calorimeter to measure temperature from 20 ° C to 300 ° C.
The temperature was raised at a rate of ° C./min, and the glass transition temperature of the composition was measured according to JIS K7121. The glass transition temperatures of the continuous phases of the thermoplastic resin compositions 1, 2, and 3 are each 12
It was 0 ° C, 145 ° C, and 120 ° C.

The methods for evaluating physical properties and the like are described below. Evaluation of crystallinity of molded products Samples were cut out from each molded product, and 20 to 300 ° C.
Up to 10 ° C./min, and the temperature of the exothermic peak due to the crystallization of SPS around 170 to 190 ° C. of the molded article, the heat of crystallization, and 265 in accordance with JIS K7121.
The temperature of the endothermic peak due to the crystal melting of SPS around 熱 275 ° C. and the heat of fusion were measured. SP in molded products
As an index indicating the degree of crystallinity of S, ΔH
I asked. It can be said that the larger the ΔH is, the more the SPS is crystallized in the molded product. ΔH (J / g) = (caloric value of endothermic peak around 265-275 ° C.) − (Caloric value of exothermic peak near 170 ° -190 ° C. of molded product) Evaluation of chemical resistance Wash with chill ethyl ketone (M
EK) for 30 seconds and removed from MEK,
I went right away. The color difference (ΔE) representing the degree of discoloration after immersion on the test piece before immersion was measured using a spectrophotometer Macbeth Color Eye CE-3000. As ΔE increases, discoloration due to MEK increases and solvent resistance deteriorates. Appearance evaluation The appearance of the molded article was visually evaluated. Evaluation is ○ = good,
X = roughness occurred.

Example 1 Cylinder temperature setting ranges C1, C2, C3,
Injection molding machine (Cycap 1) divided into four zones of C4
10/50, manufactured by Sumitomo Heavy Industries, Ltd., the C1 to C4 temperatures were both set to 260 ° C., and the thermoplastic resin composition 1 was injection molded at a mold temperature of 80 ° C. to obtain an ASTM tensile No. 1 dumbbell. . Using the obtained test pieces, measurement of ΔH, chemical resistance test, and appearance evaluation were performed. Table 1 shows the results.

Examples 2 to 5 and Comparative Examples 1 to 4 Evaluations were made in the same manner as in Example 1 except for the compositions and molding conditions shown in Table 1. The results are shown in Tables 1 and 2.

The following can be seen from the results. All the examples satisfying the conditions of the present invention show excellent evaluation results. On the other hand, Comparative Examples 1 and 3 where the molding temperature is too high are inferior in chemical resistance, and Comparative Examples 2 and 3 where the molding temperature is too low are inferior in moldability.

[0033]

[Table 1] * 1: [Tma-{(Tma-Tg) / 3}]

[0034]

[Table 2] * 1: [Tma-{(Tma-Tg) / 3}]

[0035]

As described above, according to the present invention, a thermoplastic resin containing an alkenyl aromatic resin having a syndiotactic structure and a polyphenylene ether resin and / or an alkenyl aromatic resin having no syndiotactic structure are provided. A method for producing a molded article of a thermoplastic resin composition comprising a resin composition, having excellent chemical resistance and excellent appearance was able to be provided.

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Claims (1)

[Claims] 1. A molded article comprising a thermoplastic resin composition containing the following components (A) and (B) at a weight ratio of (A) / (B) of 1/99 to 60/40. The method for producing a molded article of a thermoplastic resin composition which is molded under the condition of the following formula (1). (A): alkenyl aromatic resin having a syndiotactic structure (B): polyphenylene ether resin and / or alkenyl aromatic resin having no syndiotactic structure Tma> Tf ≧ [Tma-{(Tma- Tg) / 3}] (1) Here, Tf represents a molding temperature, Tma represents a melting temperature of the component (A), and Tg represents a glass transition temperature of the thermoplastic resin composition.