JP2008031338A - Transparent antistatic resin molded article and various molded articles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent antistatic resin molded article, such as a display case or an article for a clean room, which is excellent in transparency, heat resistance, and antistatic properties and can suppress not only the degradation of appearance and transparency due to adhered dust but also electrification. <P>SOLUTION: The transparent antistatic resin molded article is prepared by molding a resin composition which is prepared by compounding 0.1-30 pts.wt. antistatic agent (D) into 100 pts.wt. resin composition (C) which is prepared by compounding 1-90 wt.% copolymer (A) having a polystyrene-conversion weight average molecular weight of 100,000 or higher and a molecular weight distribution Mw/Mn of 1.8-3.0 and consisting of 0-10 wt.% alkyl (meth)acrylate monomer and 100-90 wt.% aromatic vinyl monomer, with 99-10 wt.% polycarbonate resin (B), provided that (A)+(B)=100 pts.wt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transparent antistatic resin molded article having good transparency, heat resistance and antistatic properties, and more particularly to a display case or clean room article comprising the same.

Polycarbonate resin (PC) is widely used in automobile parts, OA equipment housings and the like because of its excellent heat resistance and impact resistance. Polycarbonate resin is one of the plastics that is excellent in transparency because of its high light transmittance in the visible light region, and is also excellent as an optical material. For this reason, polycarbonate resins have been conventionally used as various optical materials such as plastic lenses, and recently, they are being applied to optical use parts with stricter required quality such as optical discs and light guide plates.
However, although polycarbonate resin is excellent in transparency and impact resistance, it has poor melt processability due to its high melt viscosity, and also has a property of being easily charged due to its high surface resistivity, and adheres because it is transparent. There has been a problem that the appearance is remarkably impaired by dust or the like, and the packaging material such as precision electronic parts is concerned about the influence on the contents by the discharge.
In general, as a means for imparting antistatic properties to a resin, it is known to add an antistatic agent such as a low molecular weight type such as a surfactant or a high molecular weight type comprising a specific polymer. In this case, since the molding temperature is high, the antistatic agent itself is thermally deteriorated at a high temperature during the molding process, so that the molded product is discolored or transparency is lowered due to excessive precipitation of the antistatic agent. There was a problem that occurred.
In order to solve the above problems, an alternative by adding an antistatic agent to PC / ABS alloy or transparent ABS has been proposed, but none of them has been improved sufficiently in transparency or heat resistance. Accordingly, it has been desired to obtain a transparent antistatic molded article having excellent transparency, heat resistance, and antistatic properties.
Japanese Patent Laid-Open No. 10-101921

  An object of the present invention is to provide a transparent antistatic resin molded article excellent in transparency, heat resistance and antistatic properties.

As a result of intensive studies in view of such problems, the present inventors have found that a resin composition comprising a specific copolymer composed of a specific monomer composition, a polycarbonate resin, and an antistatic agent has the above object. It has been found that this has been achieved, and the present invention has been achieved.
That is, the present invention relates to a (meth) acrylic acid alkyl ester monomer of 0 to 10% by weight and an aromatic vinyl having a polystyrene equivalent weight average molecular weight of 100,000 or more and a molecular weight distribution Mw / Mn of 1.8 to 3.0. 1 to 90% by weight of a copolymer (A) comprising 100 to 90% by weight of a monomer and a resin composition (C) comprising 99 to 10% by weight of a polycarbonate resin (B) (provided that (A) + (B ) = 100 parts by weight) to provide a transparent antistatic resin molded product obtained by molding a resin composition obtained by blending 0.1 to 30 parts by weight of the antistatic agent (D). .

  The transparent antistatic resin molded product obtained in the present invention is excellent in antistatic properties while having transparency and heat resistance, and therefore can suppress appearance defects and transparency deterioration due to adhering dust, and can be charged. It can be effectively used as a transparent antistatic resin molded product having a high industrial value that can be suppressed, particularly as a display case or a clean room product.

Hereinafter, the present invention will be described in detail.
The transparent antistatic resin molded article in the present invention has a polystyrene-equivalent weight average molecular weight of 100,000 or more and a molecular weight distribution Mw / Mn of 1.8 to 3.0 (meth) acrylic acid alkyl ester monomer 0-10. 1% to 90% by weight of copolymer (A) consisting of 100% to 90% by weight and aromatic vinyl monomer and resin composition (C) consisting of 99% to 10% by weight of polycarbonate resin (B) (provided that (A) + (B) = 100 parts by weight) is obtained by molding a resin composition obtained by blending 0.1 to 30 parts by weight of the antistatic agent (D).

As the (meth) acrylic acid ester monomer constituting the copolymer (A) in the present invention, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2 Ethyl acrylate acrylate and the like, and aromatic vinyl monomers include styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl-p-methyl styrene, Halogenated styrene, ethyl styrene, p-isopropyl styrene, pt-butyl styrene, 2,4-dimethyl styrene, divinyl benzene, etc. are exemplified, and one or more types can be selected and used. is there. Among these, methyl acrylate, butyl acrylate, methyl methacrylate, and butyl methacrylate are particularly preferable as the (meth) acrylic acid ester monomer, and styrene is preferable as the aromatic vinyl monomer.
In the present invention, monomers that can be copolymerized with these monomers within a range that does not impede its purpose, for example, vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, etc. , Maleimide monomers such as N-phenylmaleimide and N-cyclohexylmaleimide, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and (anhydrous) maleic acid, and epoxy group-containing monomers such as glycidyl methacrylate It is also possible to select one or more types for use.

  It is important that the content of the (meth) acrylic acid ester monomer in the copolymer (A) in the present invention is in the range of 0 to 10% by weight. When this content exceeds 10% by weight (the aromatic vinyl monomer is less than 90% by weight), when mixed with the polycarbonate resin (B), the transparency which is a feature of the present invention is impaired. Preferably, the (meth) acrylic acid alkyl ester monomer is 1 to 10% by weight and the aromatic vinyl monomer is 99 to 90% by weight.

  In addition, it is important that the copolymer (A) in the present invention has a polystyrene-equivalent weight average molecular weight of 100,000 or more and a molecular weight distribution Mw / Mn in the range of 1.8 to 3.0. When the weight average molecular weight in terms of polystyrene is less than 100,000, the difference in melt viscosity with the polycarbonate resin is large, so that appearance defects in the final product are likely to occur, and the molecular weight distribution Mw / Mn is 1.8 to 3.0. Deviating from the range is not preferable because the product strength tends to be impaired.

  The copolymer (A) in the present invention can be produced by a known polymerization method. Among them, a bulk polymerization method or a solution polymerization method is preferable, and a continuous bulk or solution polymerization method is more preferably used. . More specifically, a raw material in which a (meth) acrylic acid ester monomer, an aromatic vinyl monomer, and, if necessary, a solvent such as ethylbenzene, toluene, methyl ethyl ketone, etc., is supplied to the polymerization step, After the step of polymerizing the monomer and after the step, the mixed liquid containing the polymer, the unreacted monomer and / or the solvent is heated, and simultaneously or after heating, the mixture is introduced into the decompression chamber and the unreacted monomer and / or Or the separation and recovery process for separating the solvent from the polymer, and further pelletizing the polymer discharged from the recovery process by adding additives such as colorants, antioxidants, and diffusing agents as necessary. It is preferable to consist of the granulation process.

As a method for adjusting the polystyrene-equivalent weight average molecular weight (100,000 or more) and molecular weight distribution (Mw / Mn 1.8 to 3.0) of the copolymer (A) in the present invention, the polymerization method, polymerization temperature, or It can be adjusted by appropriately setting the amount of the polymerization initiator and molecular weight regulator used.
The polystyrene-converted weight average molecular weight and molecular weight distribution of the copolymer (A) in the present invention can be measured using a Shimadzu high performance liquid chromatography (HSG column) after dissolving the copolymer in tetrahydrofuran. It is.

Furthermore, the pH of the copolymer (A) in the present invention is preferably 7.0 or less, and more preferably 6.0 or less. In addition, this pH is arbitrarily adjusted by adding an acid component such as phosphoric acid when mixing the copolymer (A) and the polycarbonate or the amount of the polymerization method and the additive during polymerization. Is possible.
Further, the alkali metal salt in the copolymer (A) in the present invention is preferably less than 0.1% by weight. In addition, the content of the alkali metal salt can be arbitrarily adjusted by the polymerization method of the copolymer (A), the adjustment of the additive during polymerization and the amount thereof, or the washing method of the copolymer (A). Is possible.

  The polycarbonate resin (B) in the present invention is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds and phosgene are reacted, or a transesterification method in which a dihydroxydiaryl compound and a carbonate such as diphenyl carbonate are reacted. Representative examples include 2,2-bis (4-hydroxyphenyl) propane; polycarbonate resin produced from “bisphenol A”.

  Examples of the dihydroxydiaryl compound include bisphenol A, bis (4-hydroxydiphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2, 2-bis (4-hydroxyphenyl) octane, bisbis (4-hydroxydiphenyl) phenylmethane, 2,2-bis (4-hydroxydiphenyl-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3) -Tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5dibromophenyl) propane, 2,2-bis (4 Bis (hydroxyaryl) alkanes such as -hydroxy-3,5-dichlorophenyl) propane; , 1-bis (4-hydroxyphenyl) cyclopentane, bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4′-dihydroxydiphenyl ether, 4,4′- Dihydroxy diaryl ethers such as dihydroxy-3,3′-dimethyldiphenyl ether, 4,4′-dihydroxydiphenyl sulfide, dihydroxydiaryl sulfides such as 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfide Dihydroxy diaryl sulfoxides such as 4,4′-dihydroxydiphenyl sulfoxide, dihydro such as 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxy-3,3′-dimethyldiphenyl sulfone Siji aryl sulfones and the like.

  These may be used alone or in combination of two or more. In addition to these, piperazine, dipiperidyl hydroquinone, resorcin, 4,4′-dihydroxydiphenyls, and the like may be mixed.

  Further, the above-mentioned dihydroxydiaryl compound and a trivalent or higher valent phenol compound as shown below may be mixed and used. Trihydric or higher phenols include phloroglucin, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -heptene-2,4,6-dimethyl-2,4,6-tri- (4 -Hydroxyphenyl) -heptane, 1,3,5-tri- (4-hydroxyphenyl) -benzol, 1,1,1-tri- (4-hydroxyphenyl) -ethane and 2,2-bis- (4 4 '-(4,4'-hydroxydiphenyl) cyclohexyl) -propane and the like. In addition, when manufacturing these polycarbonate resins, a molecular weight regulator, a catalyst, etc. can be used as needed.

  The resin composition (C) in the present invention is a resin composition comprising 1 to 90 parts by weight of the above-mentioned copolymer (A) and 99 to 10 parts by weight of the polycarbonate resin (B), and the copolymer (A) is If it is less than 1 part by weight (polycarbonate resin (B) exceeds 99 parts by weight), the moldability tends to be inferior. If the copolymer (A) exceeds 90 parts by weight (polycarbonate resin (B) is 10 parts by weight). Less than) This is not preferable because the heat resistance tends to be insufficient.

  The transparent antistatic resin molded product in the present invention is 0.1 to 30 parts by weight of the antistatic agent (D) with respect to the resin composition (C) (where (A) + (B) = 100 parts by weight). It is obtained by molding a resin composition obtained by blending. If the antistatic agent (D) is less than 0.1 part by weight relative to 100 parts by weight of the resin composition (C), sufficient antistatic properties cannot be obtained, and if it exceeds 30 parts by weight, the transparency tends to decrease. Therefore, it is not preferable.

  Examples of the antistatic agent (D) used in the present invention include a cationic surfactant such as an alkylamine salt, a sulfate of a higher alcohol, a sulfate ester salt of an ethylene oxide adduct of a higher alcohol, and an ethylene oxide addition of an alkylphenol. Sulfate salts, alkane sulfonates, alkyl benzene sulfonates, alkyl sulfosuccinates, salts of naphthalene sulfonate formalin condensates, phosphate esters of higher alcohol ethylene oxide adducts, ethylene oxide adducts of alkylphenols Anionic surfactant such as phosphate ester salt, higher fatty acid sorbitan ester, higher fatty acid monoglycerin ester, higher fatty acid monoglycerin ester ethylene oxide adduct, higher alcohol ethylene oxide adduct, higher fatty acid oxidation ester Nonionic surfactants such as lene adducts, alkylphenol ethylene oxide adducts, amido ethylene oxide adducts, ethylene oxide adducts of alkylamines, polyalkylene glycols, polyalkylene glycol copolymers, polyether ester amides, etc. 1 type or 2 types or more can be used.

  In the present invention, it is also possible to add an ultraviolet absorber, a lubricant, a release agent, a flame retardant, an antioxidant and the like as long as the characteristics are not impaired.

  In the present invention, other thermoplastic resins such as polyamide, polybutylene terephthalate, polyphenylene oxide, polyoxymethylene, and polyethylene can be further mixed within a range that maintains transparency as necessary.

  Furthermore, there is no restriction | limiting in particular in the mixing method of each component in this invention, It can mix using an extruder, a Banbury mixer, a roll, a kneader, etc.

  The molding temperature for molding the transparent antistatic resin molded product of the present invention is preferably 210 to 260 ° C. If the molding temperature is less than 210 ° C, warpage and deformation are likely to occur due to residual molding strain, and if it exceeds 260 ° C, the antistatic agent itself tends to cause thermal deterioration and poor appearance due to silver streak or burn. .

  In addition, in order to obtain the transparent antistatic resin molded product of the present invention, it can be molded by a molding method according to the purpose, such as injection molding, extrusion molding, or profile extrusion molding.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not restrict | limited at all by these.

〔Example〕
-Copolymer (A)-
Copolymer A-1: A copolymer was produced using a continuous polymerization apparatus comprising one fully mixed reaction tank having a capacity of 20 liters. 92 parts by weight of styrene as an aromatic vinyl monomer, 8 parts by weight of methyl methacrylate as a (meth) acrylic acid alkyl ester monomer, 0.03 parts by weight of t-dodecyl mercaptan, and t-butyl par as a polymerization initiator Polymerization is carried out by continuously supplying a polymerization raw material consisting of 0.015 parts by weight of oxy (2-ethylhexanoate) and 10 parts by weight of ethylbenzene to the reaction vessel at a rate of 13 kg / h using a plunger pump. The polymerization conversion rate at the reactor outlet was adjusted to 53.5 parts by weight by adjusting the temperature. The polymerization temperature at this time was 150 ° C. The number of revolutions in the reaction vessel was 150 rpm, and the polymerization temperature was measured by inserting thermocouples in the upper, middle, and lower portions of the reaction vessel. The temperature at the three locations was an average value of ± 0.2 ° C. It is considered that the polymerization liquid is uniformly mixed. Following the polymerization, the polymerization solution continuously drawn out from the reaction vessel is supplied to a devolatilizer to separate volatile components such as unreacted monomers and organic solvents, and then the resin is passed through an extruder. Pelletization was performed to prepare a copolymer A-1.
Polystyrene-converted average weight molecular weight Mw and molecular weight distribution Mw / Mn were measured using high-performance liquid chromatography (manufactured by Shimadzu Corporation) and Shimadzu HSG column in 0.02 g of the obtained copolymer dissolved in 10 ml of THF (hereinafter the same When measured by a method), they were 200,000 and 2.1, respectively. Further, the polymer was incinerated, dissolved in pure water, and quantified by ICP method and atomic absorption method (hereinafter measured by the same method). The content of alkali metal salt was 0.003% by weight, 1 g of the combined product was dissolved in 40 ml of acetone, then 40 ml of methanol and 40 ml of pure water were added, and the pH of the supernatant obtained by allowing to stand for 1 hour was measured (hereinafter measured by the same method) and found to be 6.3. .

  Copolymer A-2: Copolymer A-2 was prepared in the same manner as Copolymer A-1, except that 5 parts by weight of methyl methacrylate, 95 parts by weight of styrene, and 0.01 parts by weight of t-dodecyl mercaptan were used. Created. The copolymer A-2 had Mw of 250,000, Mw / Mn of 2.2, an alkali metal salt content of 0.002% by weight, and a pH of 6.4.

  Copolymer A-3: Copolymer A-3 was prepared in the same manner as Copolymer A-1, except that 100 parts by weight of styrene and 0.00 parts by weight of t-dodecyl mercaptan were used. In addition, Mw of copolymer A-3 was 280,000, Mw / Mn was 2.1, content of alkali metal salt was 0.002% by weight, and pH was 6.4.

  Copolymer Ai: Copolymer Ai was prepared in the same manner as Copolymer A-1, except that 20 parts by weight of methyl methacrylate, 80 parts by weight of styrene, and 0.02 parts by weight of t-dodecyl mercaptan were used. Created. The copolymer Ai had an Mw of 240,000, an Mw / Mn of 2.2, an alkali metal salt content of 0.003% by weight, and a pH of 6.4.

  Copolymer A-ii: Copolymer A-ii was prepared in the same manner as Copolymer A-1, except that 80 parts by weight of methyl methacrylate, 20 parts by weight of styrene, and 0.02 parts by weight of t-dodecyl mercaptan were used. Created. The copolymer A-ii had an Mw of 100,000, an Mw / Mn of 2.2, an alkali metal salt content of 0.003% by weight, and a pH of 6.4.

  Copolymer A-iii: Nitrogen-substituted glass reactor was charged with 110 parts of pure water and heated to 70 ° C. Thereafter, an emulsifier aqueous solution in which 1.0 part of potassium oleate was dissolved in 20 parts of pure water and a monomer mixture consisting of 5 parts by weight of methyl methacrylate, 95 parts by weight of styrene and 0.01 part by weight of t-dodecyl mercaptan was added for 4 hours. Over a period of time. Thereafter, the polymerization was continued for 3 hours to complete the polymerization. After the completion of polymerization, 5 parts of 10% aqueous sodium hydroxide solution is added per 100 parts by weight of copolymer latex (solid content), and then salted out, dehydrated and dried using magnesium sulfate to obtain copolymer A-iii. It was. The copolymer A-iii had an Mw of 260,000, an Mw / Mn of 2.5, an alkali metal salt content of 0.85% by weight, and a pH of 8.9.

-Polycarbonate resin (B)-
B-1: Caliber 200-20 (manufactured by Sumitomo Dow)

-Antistatic agent (D)-
D-1: Electro stripper TS-6 (manufactured by Kao Corporation)

[Examples 1-5, Comparative Examples 1-5]]
About each said component, it mixed in the ratio shown in Table 1, and the predetermined | prescribed pellet was obtained with the twin-screw extruder (Nippon Steel Works TEM-35) which set the cylinder temperature to 240 degreeC. The obtained pellets were preliminarily dried at 100 ° C., and various test pieces were obtained at a cylinder set temperature of 250 ° C. using an injection molding machine (J-150EP manufactured by Nippon Steel Works). However, in Comparative Example 5, since the injection molding was not possible at 250 ° C., the cylinder temperature was set to 300 ° C. The results are shown in Table 1. Various test conditions are as follows.

Transparency : A flat plate of 100 × 50 × 3 mm was prepared, and haze was measured using a haze meter (HM-150 Murakami Color Research Laboratory). unit:%
Heat resistance : The deflection temperature under load was measured according to ISO 75 under the condition of 0.46 MPa. Unit: ° C

Antistatic property : A square test piece having a thickness of 3 mm was prepared, the condition was adjusted at 23 ° C. and humidity of 50% RH for one month, and the surface specific resistance value before and after washing with water was measured by Toago Denshi Kogyo's Ultramegame. Measurement was performed with a meter SN8210. Unit: Ω
Appearance : Yellowness YI (transmitted light) was measured with CMS-35SP manufactured by Murakami Color Research Laboratory. It shows that the smaller the YI value, the better the yellowness.

Since the transparent antistatic resin molded product (especially display case or clean room product) in the present invention is excellent in transparency, heat resistance and antistatic property, it is possible to suppress deterioration in appearance and transparency due to adhering dust, and charge can be prevented. Since it can be suppressed, it can be used as a transparent antistatic resin molded product such as a display case or a clean room product with high industrial value.

Claims (6)

Polystyrene-converted weight average molecular weight of 100,000 or more and molecular weight distribution Mw / Mn of 1.8 to 3.0 (meth) acrylic acid alkyl ester monomer 0 to 10% by weight and aromatic vinyl monomer 100 -90% by weight of copolymer (A) 1-90% by weight and polycarbonate resin (B) 99% by weight of resin composition (C) (provided that (A) + (B) = 100 parts by weight A transparent antistatic resin molded product obtained by molding a resin composition obtained by blending 0.1 to 30 parts by weight of an antistatic agent (D) with respect to The copolymer (A) is a copolymer comprising 1 to 10% by weight of a (meth) acrylic acid alkyl ester monomer and 99 to 90% by weight of an aromatic vinyl monomer. Transparent antistatic resin molded product. The transparent antistatic resin molded article according to claim 1 or 2, wherein the pH of the copolymer (A) is less than 7. The transparent antistatic resin molded article according to claim 1 or 2, wherein the content of the alkali metal salt in the copolymer (A) is less than 0.1% by weight. It is a display case, The transparent antistatic resin molded product of Claims 1-4. The transparent antistatic resin molded product according to claim 1, which is a clean room product.