JP6376020B2 - Thermoplastic resin composition and molded article thereof - Google Patents

Description

  The present invention relates to a thermoplastic resin composition obtained by blending a graft copolymer and a vinyl copolymer, and a molded article thereof.

  ABS resin obtained by graft-copolymerizing aromatic vinyl compounds such as styrene and α-methylstyrene, vinyl cyanide compounds such as acrylonitrile and methacrylonitrile on rubbery polymers such as diene rubber is Since it is excellent in mechanical strength such as impact and rigidity, moldability and cost performance, it is widely used in application fields such as home appliances, communication related equipment, general goods and medical related equipment.

  As an example of home appliances, as a washing machine application, in recent years, ultra-concentrated compact detergents known under trade names such as “Nanox” (registered trademark) and Ultra Attack neo have been spreading. These ultra-concentrated compact detergents tend to deteriorate the resin as compared with conventional detergents, and resin materials used for washing machine applications are required to have chemical resistance against them. In medical-related equipment applications, chemical resistance against disinfecting alcohol is required.

  Until now, as a resin composition excellent in transparency, chemical resistance and color tone stability, it has been a thermoplastic resin composition in which a graft copolymer (B) is dispersed in a vinyl copolymer (A). Thus, a thermoplastic resin composition in which the proportion of the triple sequence of acrylonitrile monomer-derived units present in the acetone-soluble component of the thermoplastic resin composition is 10% by weight or less with respect to the acetone-soluble component is obtained. It has been proposed (see, for example, Patent Document 1). However, the transparent ABS resin disclosed in Patent Document 1 is still insufficient for high chemical resistance against chemicals such as organic solvents and solvents such as detergents and alcohols for disinfection that are required in recent years. The fact is that the use is limited.

  On the other hand, as means for improving the chemical resistance of ABS resin, it is generally known to increase the content of vinyl cyanide compound, for example, 10 to 30% by weight of aromatic vinyl monomer, unsaturated In a vinyl copolymer obtained by polymerizing a vinyl monomer mixture containing 50 to 85% by weight of a carboxylic acid alkyl ester monomer and 8 to 15% by weight of a vinyl cyanide monomer, A thermoplastic resin composition in which a graft copolymer (B) obtained by graft polymerization of one or more vinyl monomers or a vinyl monomer mixture in the presence of a polymer is dispersed. Thermoplastic whose ratio of triple sequence of units derived from acrylonitrile monomer present in acetone-soluble component of thermoplastic resin composition is 0.001 wt% or more and 10 wt% or less with respect to acetone-soluble component Tree Composition (see, for example, Patent Document 2), aromatic vinyl monomer 10-30% by weight, unsaturated carboxylic acid alkyl ester monomer 30-80% by weight, vinyl cyanide monomer 1-10 A vinyl copolymer obtained by polymerizing a vinyl monomer mixture containing% by weight, and a graft copolymer obtained by graft polymerizing one or more vinyl monomers in the presence of a rubbery polymer. A transparent thermoplastic resin composition (for example, patents) having a reduced viscosity of 0.70 to 0.75 dl / g in methyl ethyl ketone of an acetone-soluble component of the resin composition. Reference 3) has been proposed.

  On the other hand, as a technique for improving the paintability, impact resistance and processability of ABS resin, a rubber-containing graft copolymer (A) having a weight average molecular weight of 250,000 to 450,000 and an aromatic vinyl monomer And a hard polymer containing a vinyl cyanide monomer having a weight average molecular weight of 100,000 to 200,000 and containing 20 to 30% by weight of the vinyl cyanide monomer (BI) And a hard polymer mixture (B) comprising a hard polymer (B-II) having a weight average molecular weight of less than 100,000 and containing 35 to 50% by weight of a vinyl cyanide monomer (for example, , See Patent Document 4). Further, as means for improving the impact resistance and fluidity of ABS resin, for example, a copolymer obtained by copolymerizing a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer, and rubber Acetone-soluble component in a rubber-reinforced thermoplastic resin composition containing a graft copolymer obtained by graft-polymerizing a monomer mixture containing at least an aromatic vinyl monomer and a vinyl cyanide monomer in the presence of a glassy polymer The proportion of the component having a molecular weight of less than 50,000 in the acetone-soluble component relative to the total weight is less than 30% by weight and the proportion of the component having a molecular weight of 250,000 or more is 5 to 15% by weight, and the weight-average molecular weight of the acetone-soluble component A rubber-reinforced thermoplastic resin composition having a molecular weight distribution (Mw / Mn) represented by a ratio of (Mw) to number average molecular weight (Mn) in the range of 1.5 to 2.5 ( In example, such as Patent Document 5) it has been proposed.

  Furthermore, the ABS resin tends to yellow when directly exposed to sunlight, and there is a problem that it tends to yellow (dark yellow) even in a dark environment. As a means for improving the dark yellowing of ABS resin, for example, 100 parts by weight of rubber-reinforced thermoplastic resin (A), phenolic antioxidant (a), hindered amine light stabilizer (b) and phosphorus 0.5 to 3.5 parts by weight of total antioxidant (c), 0.25 to 0.75 parts by weight of benzotriazole light stabilizer (d), ethylene / carbon monoxide / (meth) acrylic The acid ester copolymer (e) is in the range of 0.5 to 6.0 parts by weight, and the weight ratio of the rubber polymer (a) to 100 parts by weight of the rubber-reinforced thermoplastic resin (A) is ( A): A thermoplastic resin composition in which the weight ratio of (a): (b): (c) is 1: 0.004-0.008: 0.0020-0.005: 0.006-0.05. (For example, refer patent document 6) etc. are proposed.

JP 2002-179873 A JP 2010-116427 A JP 2011-190388 A JP 2000-7877 A JP 2012-136644 A JP 2014-98113 A

  However, even with the techniques disclosed in Patent Documents 1 to 6, chemical resistance to the ultra-concentrated compact detergent is still insufficient, and there has been a problem that yellowing occurs in the dark when contacted with the super-concentrated compact detergent. Further, the technique disclosed in Patent Document 3 has a problem of insufficient fluidity, and the techniques disclosed in Patent Documents 1 to 3 and 5 have a problem of insufficient impact resistance.

  In view of the above-mentioned problems in the prior art, the present invention is a thermoplastic resin composition that is excellent in fluidity, excellent in chemical resistance and impact resistance, and capable of obtaining a molded product with reduced dark yellowing during chemical contact. The purpose is to provide goods.

As a result of intensive studies to achieve the above object, the present inventor has found that the above-described problems can be solved by the following configuration.
(1) Vinyl containing at least 60 to 80% by weight of an aromatic vinyl monomer (a1) and 20 to 40% by weight of a vinyl cyanide monomer (a2) in the presence of the rubbery polymer (r) 20 to 40 parts by weight of the graft copolymer (A) obtained by graft copolymerization of the monomer mixture (a) is added to at least the aromatic vinyl monomer (b1) and the vinyl cyanide monomer (b2). Is a thermoplastic resin composition comprising 60 to 80 parts by weight of a vinyl copolymer (B) obtained by copolymerizing a vinyl monomer mixture (b) containing the thermoplastic resin, The acetone-soluble component (C) in the composition has a weight average molecular weight of 150,000 to 250,000, a degree of dispersion of 2.8 or more, and a content of vinyl cyanide monomer-derived units of 29 to 36% by weight. And
10 to 30% by weight of component (C-1) having a content of vinyl cyanide monomer-derived unit of 35% by weight or more in 100% by weight of acetone-soluble component (C), vinyl cyanide single amount 70-90 weight% of components (C-2) whose content of a body-derived unit is less than 35 weight%,
In 100% by weight of the component (C-1), the proportion of components having a molecular weight of 30,000 to 200,000 is 70% by weight or more, the proportion of components having a molecular weight exceeding 200,000 is 10 to 20% by weight, and the molecular weight is 30. The proportion of ingredients less than 1,000 is 20% by weight or less,
In 100% by weight of the component (C-2), the proportion of the component having a molecular weight of 30,000 to 200,000 is 40 to 60% by weight, the proportion of the component having a molecular weight exceeding 200,000 is 20% by weight or more, and the molecular weight is 30. A thermoplastic resin composition in which the proportion of components less than 1,000 is 20% by weight or less.
(2) Vinyl containing at least 60 to 80% by weight of the aromatic vinyl monomer (a1) and 20 to 40% by weight of the vinyl cyanide monomer (a2) in the presence of the rubbery polymer (r). 20 to 40 parts by weight of the graft copolymer (A) obtained by graft copolymerization of the monomer mixture (a) is added to at least the aromatic vinyl monomer (b1) and the vinyl cyanide monomer (b2). ) Containing a vinyl monomer mixture (b) containing 60 to 80 parts by weight of a vinyl copolymer (B), and a method for producing a thermoplastic resin composition,
The vinyl copolymer (B) contains at least an aromatic vinyl monomer (b1) of 55 to 65% by weight and a vinyl cyanide monomer (b2) of 35 to 45% by weight. becomes the body mixture (b-1) copolymerizing, high nitrile-containing vinyl copolymer having a weight average molecular weight is 100,000～150,000 and (B-1), at least an aromatic vinyl monomer (B1) A vinyl monomer mixture ( b-2 ) containing more than 65% by weight and 75% by weight or less and vinyl cyanide monomer (b2) of 25% by weight or more and less than 35% by weight is copolymerized. And a method for producing a thermoplastic resin composition in combination with a high molecular weight vinyl copolymer (B-2) having a weight average molecular weight of 250,000 to 350,000.
(3) Compounding ratio (weight ratio) of the high nitrile-containing vinyl copolymer (B-1) and the high molecular weight vinyl copolymer (B-2) constituting the vinyl copolymer (B) ) Is (B-1) / (B-2) = 33/67 to 67/33. The method for producing a thermoplastic resin composition according to (2).
(4) A molded product obtained by molding the thermoplastic resin composition according to (1).
(5) (2) or (3) the production method of a molded article obtained by molding the thermoplastic resin composition obtained by the production method described.

  The thermoplastic resin composition of the present invention is excellent in fluidity. With the thermoplastic resin composition of the present invention, it is possible to obtain a molded article having excellent chemical resistance and impact resistance and reduced darkness yellowing during chemical contact. According to the method for producing a thermoplastic resin composition of the present invention, thermoplasticity that can provide a molded product having high fluidity, excellent chemical resistance and impact resistance, and reduced darkness yellowing at the time of chemical contact. A resin composition can be provided.

It is the schematic which shows the chemical-resistance evaluation method in an Example and a comparative example.

  The thermoplastic resin composition of the present invention is obtained by blending a later-described graft copolymer (A) with a later-described vinyl-based copolymer (B). By mix | blending a graft copolymer (A), the fluidity | liquidity of a thermoplastic resin composition can be improved and the impact resistance of a molded article can be improved. By blending the vinyl copolymer (B), the fluidity of the thermoplastic resin composition can be improved, the chemical resistance of the molded product can be improved, and yellowing in the dark at the time of chemical contact can be reduced. .

  The graft copolymer (A) constituting the thermoplastic resin composition of the present invention comprises at least 60 to 80% by weight of the aromatic vinyl monomer (a1) in the presence of the rubbery polymer (r), cyanide. It is obtained by graft copolymerization of a vinyl monomer mixture (a) containing 20 to 40% by weight of the vinyl monomer (a2). The vinyl monomer mixture (a) may further contain other monomers copolymerizable with the above (a1) and (a2).

  Examples of the rubber polymer (r) include polybutadiene, poly (butadiene-styrene) (SBR), poly (butadiene-acrylonitrile) (NBR), polyisoprene, poly (butadiene-butyl acrylate), poly (butadiene- Methyl methacrylate), poly (butyl acrylate-methyl methacrylate), poly (butadiene-ethyl acrylate), ethylene-propylene rubber, poly (ethylene-isoprene), poly (ethylene-methyl acrylate), natural rubber, etc. Can be mentioned. Two or more of these may be used. Of these, polybutadiene, SBR, NBR, ethylene-propylene rubber, and natural rubber are preferable from the viewpoint of further improving impact resistance.

  The content of the rubbery polymer (r) is 20 with respect to the total amount of the rubbery polymer (r) constituting the graft copolymer (A) and the vinyl monomer mixture (a) described later. ~ 80 wt% is preferred. When the content of the rubbery polymer (r) is 20% by weight or more, the impact resistance of the molded product can be further improved. The content of the rubbery polymer (r) is more preferably 35% by weight or more. On the other hand, if the content of the rubbery polymer (r) is 80% by weight or less, the moldability of the thermoplastic resin composition can be further improved. The content of the rubber-like polymer (r) is more preferably 60% by weight or less.

  The weight average particle diameter of the rubber polymer (r) is not particularly limited, but is preferably 0.1 μm or more, and more preferably 0.15 μm or more from the viewpoint of improving the impact resistance of the molded product. On the other hand, from the viewpoint of improving the impact resistance and fluidity of the molded product, 1.5 μm or less is preferable, and 0.5 μm or less is more preferable. Further, from the viewpoint of further improving the rigidity and impact resistance of the molded product, the SBR having a relatively large particle diameter having a weight average particle diameter of 0.5 to 1.2 μm and the weight average particle diameter of 0.1 to 0.00. It is preferable to use polybutadiene having a relatively small particle diameter of 3 μm.

  Here, the weight average particle diameter of the rubber polymer (r) is determined by diluting and dispersing the rubber polymer latex with an aqueous medium, and measuring the laser scattering diffraction particle size distribution analyzer “LS 13 320” (Beckman Coulter, Inc.). )) And can be calculated from the particle size distribution measured.

  Examples of the aromatic vinyl monomer (a1) include styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, vinyltoluene, and t-butylstyrene. Two or more of these may be contained. Among these, styrene is preferable from the viewpoint of further improving the fluidity of the thermoplastic resin composition and the rigidity of the molded product.

  The content of the aromatic vinyl monomer (a1) in the vinyl monomer mixture (a) is from the viewpoint of further improving the fluidity of the thermoplastic resin composition and the rigidity of the molded product. Of the total 100% by weight of the body mixture (a), 60% by weight or more is preferable, and 70% by weight or more is more preferable. On the other hand, the content of the aromatic vinyl monomer (a1) in the vinyl monomer mixture (a) is preferably 80% by weight or less from the viewpoint of improving fluidity and impact resistance of the molded product, 75% by weight or less is more preferable.

  Examples of the vinyl cyanide monomer (a2) include acrylonitrile, methacrylonitrile, ethacrylonitrile and the like. Two or more of these may be contained. Among these, acrylonitrile is preferable from the viewpoint of further improving the chemical resistance and impact resistance of the molded product.

  The content of the vinyl cyanide monomer (a2) in the vinyl monomer mixture (a) is selected from the viewpoint of further improving the chemical resistance and impact resistance of the molded product. Of the total 100% by weight of a), 20% by weight or more is preferable, and 25% by weight or more is more preferable. On the other hand, the content of the vinyl cyanide monomer (a2) in the vinyl monomer mixture (a) is preferably 40% by weight or less, and preferably 30% by weight or less from the viewpoint of improving the color tone of the molded product. More preferred.

  Other monomers copolymerizable with these are vinyl monomers other than the above-mentioned aromatic vinyl monomer (a1) and vinyl cyanide monomer (a2), If it does not impair the effect of invention, there will be no restriction | limiting in particular. Specific examples include unsaturated carboxylic acid alkyl ester monomers, unsaturated fatty acids, acrylamide monomers, and maleimide monomers. Two or more of these may be contained.

  As an unsaturated carboxylic acid alkyl ester monomer, for example, an ester of an alcohol having 1 to 6 carbon atoms and acrylic acid or methacrylic acid is preferable. The ester of an alcohol having 1 to 6 carbon atoms and acrylic acid or methacrylic acid may further have a substituent such as a hydroxyl group or a halogen group. Examples of the ester of an alcohol having 1 to 6 carbon atoms and acrylic acid or methacrylic acid include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acryl Examples include acid 2,3,4,5,6-pentahydroxyhexyl, 2,3,4,5-tetrahydroxypentyl (meth) acrylate, and the like. Two or more of these may be contained. “(Meth) acrylic acid” refers to acrylic acid or methacrylic acid.

  Examples of the unsaturated fatty acid include itaconic acid, maleic acid, fumaric acid, butenoic acid, acrylic acid, and methacrylic acid.

  Examples of the acrylamide monomer include acrylamide, methacrylamide, N-methylacrylamide and the like.

  Examples of maleimide monomers include N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-cyclohexylmaleimide, Examples thereof include N-phenylmaleimide.

  In the present invention, the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is not particularly limited, but is preferably 50,000 to 300,000. If the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is 50,000 or more, the chemical resistance of the molded product can be further improved. On the other hand, if the weight average molecular weight of the acetone-soluble component of the graft copolymer (A) is 300,000 or less, the fluidity can be further improved. 100,000 or less is more preferable.

  For the graft copolymer (A) having a weight average molecular weight in the range of 50,000 to 300,000 for the acetone-soluble component, for example, an initiator or a chain transfer agent described later is used, and a polymerization temperature is set in a preferable range described later. For example, it can be easily manufactured.

  In the present invention, the degree of dispersion of the acetone-soluble component of the graft copolymer (A) is not particularly limited, but is preferably 2.0 to 2.5. If the degree of dispersion of the acetone soluble part of the graft copolymer (A) is 2.0 to 2.5, the graft copolymer (A) can be easily produced, and the flowability and resistance of the molded product can be improved. Chemical properties can be further improved.

  For the graft copolymer (A) having a dispersity of acetone-soluble in the range of 2.0 to 2.5, for example, an initiator or a chain transfer agent described below is used, and the polymerization temperature is set in a preferable range described below. For example, it can be easily manufactured.

Here, the weight average molecular weight and dispersity of the acetone-soluble component of the graft copolymer (A) were measured by concentrating the filtrate obtained by filtering the acetone-insoluble component from the graft copolymer (A) using a rotary evaporator. It can be determined by converting polystyrene as a standard substance from a GPC chromatogram measured using a solution of about 0.2% by weight in which about 0.03 g of soluble component is dissolved in about 15 g of tetrahydrofuran. The GPC measurement can be performed under the following conditions.
Measuring device: Waters 2695
Column temperature: 40 ° C
Detector: RI2414 (differential refractometer)
Carrier eluent flow rate: 0.3 ml / min (solvent: tetrahydrofuran)
Column: TSKgel SuperHZM-M (6.0 mm ID × 15 cm), TSKgel SuperHZM-N (6.0 mm ID × 15 cm) in series (both Tosoh).

  Although there is no restriction | limiting in particular in the graft rate of a graft copolymer (A), From a viewpoint of improving the impact resistance of a molded article, 10 to 100% is preferable.

Here, the graft ratio of the graft copolymer (A) can be determined by the following method. First, 80 ml of acetone was added to about 1 g (m: sample weight) of the graft copolymer (A) and refluxed in a hot water bath at 70 ° C. for 3 hours. p. After centrifuging at m (10000 G) for 40 minutes, the insoluble matter is filtered to obtain an acetone insoluble matter. The obtained acetone insoluble matter is dried under reduced pressure at 80 ° C. for 5 hours, its weight (n) is measured, and the graft ratio is calculated from the following formula. Here, X is the rubbery polymer content (%) of the graft copolymer (A).
Graft ratio (%) = {[(n) − ((m) × X / 100)] / [(m) × X / 100]} × 100.

  In this invention, there is no restriction | limiting in particular in the manufacturing method of a graft copolymer (A), Arbitrary methods, such as an emulsion polymerization method, a suspension polymerization method, a continuous block polymerization method, and a solution continuous polymerization method, can be used. The emulsion polymerization method or the bulk polymerization method is preferable, the particle size of the rubbery polymer (r) can be easily adjusted to a desired range, and the polymerization stability can be easily adjusted by removing heat during polymerization. Therefore, the emulsion polymerization method is more preferable.

  When the graft copolymer (A) is produced by an emulsion polymerization method, the charging method of the rubbery polymer (r) and the vinyl monomer mixture (a) is not particularly limited. For example, all of these may be charged in the initial batch, or a part of the vinyl monomer mixture (a) may be continuously charged in order to adjust the distribution of the copolymer composition. A part or all of the monomer mixture (a) may be divided and charged. Here, continuously charging a part of the vinyl monomer mixture (a) means charging a part of the vinyl monomer mixture (a) in the initial stage and continuously charging the remainder over time. Means. In addition, dividing and charging part or all of the vinyl monomer mixture (a) means charging part or all of the vinyl monomer mixture (a) at a time after the initial charging. means.

  When the graft copolymer (A) is produced by an emulsion polymerization method, various surfactants may be added as an emulsifier. As the various surfactants, anionic surfactants such as carboxylate type, sulfate ester type, and sulfonate type are particularly preferably used. Two or more of these may be combined. In addition, as a salt said here, alkali metal salts, such as sodium salt, lithium salt, potassium salt, ammonium salt, etc. are mentioned.

  Examples of carboxylate type emulsifiers include caprylate, caprate, laurate, myristate, palmitate, stearate, oleate, linoleate, linolenate, and rosinate. , Behenate, dialkylsulfosuccinate and the like.

  Examples of the sulfate ester type emulsifier include castor oil sulfate ester, lauryl alcohol sulfate ester, polyoxyethylene lauryl sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, and the like. .

  Examples of the sulfonate type emulsifier include dodecylbenzene sulfonate, alkyl naphthalene sulfonate, alkyl diphenyl ether disulfonate, naphthalene sulfonate condensate, and the like.

  When the graft copolymer (A) is produced by an emulsion polymerization method, an initiator may be used as necessary. Examples of the initiator include peroxides, azo compounds, and water-soluble potassium persulfate. Two or more of these may be combined. Initiators are also used in redox systems.

  Examples of the peroxide include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, t-butyl isopropyl carbonate, di-t-butyl peroxide, t-butyl peroctate, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (T-Butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexanoate, etc. are mentioned. Of these, cumene hydroperoxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, and 1,1-bis (t-butylperoxy) cyclohexane are particularly preferably used. It is done.

  Examples of the azo compound include azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2-cyano-2-propylazo. Formamide, 1,1′-azobiscyclohexane-1-carbonitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, 1-t-butylazo-2 -Cyanobutane, 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane and the like. Of these, azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), and 1,1′-azobiscyclohexane-1-carbonitrile are particularly preferably used.

  The addition amount of the initiator used for producing the graft copolymer (A) is not particularly limited, but the weight average molecular weight and the degree of dispersion of the acetone-soluble portion of the graft copolymer (A) are within the above-mentioned ranges. From the viewpoint of easy adjustment to 0.1 to 0.5 parts by weight with respect to a total of 100 parts by weight of the rubbery polymer (r) and the vinyl monomer mixture (a).

  When producing the graft copolymer (A), a chain transfer agent may be used. By using a chain transfer agent, the weight average molecular weight, dispersity, and graft ratio of the acetone-soluble component of the graft copolymer (A) can be easily adjusted to a desired range.

  Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan and n-octadecyl mercaptan, and terpenes such as terpinolene. Two or more of these may be combined. Of these, n-octyl mercaptan and t-dodecyl mercaptan are preferably used.

  The addition amount of the chain transfer agent used for producing the graft copolymer (A) is not particularly limited, but the weight average molecular weight and degree of dispersion of the graft copolymer (A), and the graft ratio are within the above-mentioned ranges. From the viewpoint of easy adjustment, the amount is preferably 0.05 parts by weight or more and more preferably 0.2 parts by weight or more with respect to 100 parts by weight in total of the rubbery polymer (r) and the vinyl monomer mixture (a). . On the other hand, 0.7 parts by weight or less is preferable, and 0.6 parts by weight or less is more preferable.

  When the graft copolymer (A) is produced by an emulsion polymerization method, the polymerization temperature is not particularly limited, but it is easy to adjust the weight average molecular weight, the degree of dispersion, and the graft ratio of the graft copolymer (A) to the above ranges. From the standpoint of emulsification stability, 40 to 70 ° C is preferable.

  When the graft copolymer (A) is produced by an emulsion polymerization method, it is common to add a coagulant to the graft copolymer latex and recover the graft copolymer (A). As the coagulant, an acid or a water-soluble salt is preferably used.

  Examples of the acid include sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid and the like. Examples of the water-soluble salt include calcium chloride, magnesium chloride, barium chloride, aluminum chloride, magnesium sulfate, aluminum sulfate, aluminum ammonium sulfate, aluminum potassium sulfate, and sodium aluminum sulfate. Two or more of these may be combined. From the viewpoint of improving the color tone of the molded article, it is preferable not to leave an emulsifier in the thermoplastic resin composition, and it is preferable to use an alkali fatty acid salt as the emulsifier and to perform acid coagulation.

The vinyl copolymer (B) constituting the thermoplastic resin composition of the present invention is a vinyl monomer containing at least an aromatic vinyl monomer (b1) and a vinyl cyanide monomer (b2). It is obtained by copolymerizing the body mixture (b). The vinyl monomer mixture (b) may further contain other monomers copolymerizable with the above (b1) and (b2).
Examples of the aromatic vinyl monomer (b1) include those exemplified as the aromatic vinyl monomer (a1), and styrene is preferable.

  The content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture (b) is from the viewpoint of further improving the fluidity of the thermoplastic resin composition and the rigidity of the molded product. Of the total 100% by weight of the body mixture (b), 55% by weight or more is preferable, 60% by weight or more is more preferable, and 62% by weight or more is more preferable. On the other hand, the content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture (b) is preferably 75% by weight or less from the viewpoint of further improving the fluidity and impact resistance of the molded product. 72 wt% or less is more preferable, and 70 wt% or less is more preferable.

  Examples of the vinyl cyanide monomer (b2) include those exemplified as the vinyl cyanide monomer (a2), and acrylonitrile is preferred.

  The content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture (b) improves the chemical resistance and impact resistance of the molded product, and reduces yellowing in the dark at the time of chemical contact. From the viewpoint of further reduction, in the total 100% by weight of the vinyl monomer mixture (b), 25% by weight or more is preferable, 28% by weight or more is more preferable, and 30% by weight or more is more preferable. On the other hand, the content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture (b) is preferably 45% by weight or less, more preferably 40% by weight or less from the viewpoint of further improving impact resistance. More preferred is 38% by weight or less.

  Other monomers copolymerizable with these are vinyl monomers other than the above-mentioned aromatic vinyl monomer (b1) and vinyl cyanide monomer (b2), If it does not impair the effect of invention, there will be no restriction | limiting in particular. Specifically, what was illustrated as another monomer in a vinyl-type monomer mixture (a) is mentioned.

  In the present invention, the weight average molecular weight of the vinyl copolymer (B) is not particularly limited, but is preferably 100,000 to 350,000. 160,000-250,000 is more preferable. If the weight average molecular weight of the vinyl copolymer (B) is 100,000 or more, the chemical resistance of the molded product can be further improved, and yellowing in the dark at the time of chemical contact can be further reduced. 16,000 or more is more preferable. On the other hand, if the weight average molecular weight of the vinyl copolymer (B) is 350,000 or less, the fluidity can be further improved. 25,000 or less is more preferable.

  In the present invention, the degree of dispersion of the vinyl copolymer (B) is not particularly limited, but is preferably 2.0 to 3.5. If the degree of dispersion of the vinyl copolymer (B) is 2.0 or more, the vinyl copolymer (B) can be easily produced. 2.5 or more is more preferable. On the other hand, if the degree of dispersion of the vinyl copolymer (B) is 3.5 or less, the fluidity and chemical resistance of the molded product can be further improved, and yellowing in the dark at the time of chemical contact can be further reduced. it can.

  Here, the weight average molecular weight and dispersity of the vinyl copolymer (B) were determined using a solution of about 0.2% by weight obtained by dissolving about 0.03 g of the vinyl copolymer (B) in about 15 g of tetrahydrofuran. It can be measured in the same manner as the graft copolymer (A).

  In the present invention, as the vinyl copolymer (B), two or more kinds of copolymers obtained by copolymerizing monomer mixtures (b) having different monomer compositions and composition ratios may be used. Two or more types of copolymers having different weight average molecular weights may be used. For example, as the vinyl copolymer (B), a high nitrile-containing vinyl copolymer (B-1) described later and a high molecular weight vinyl copolymer (B-2) may be combined. In this case, it is preferable that the composition ratio and the weight average molecular weight of the monomer mixture (b) are in the above-mentioned preferable ranges as the whole vinyl copolymer (B) including two or more kinds of copolymers.

  In the present invention, the method for producing the vinyl copolymer (B) is not particularly limited, and any method such as a suspension polymerization method, an emulsion polymerization method, a bulk polymerization method, and a solution polymerization method can be used. Of these, bulk polymerization and suspension polymerization are preferred from the viewpoints of ease of polymerization control, ease of post-treatment and productivity. From the viewpoint of fluidity of the resulting thermoplastic resin composition, chemical resistance and color tone of the molded product, and ease of adjustment of the weight average molecular weight and dispersity of the vinyl copolymer (B), it is suspended. A polymerization method is preferably used. By the suspension polymerization method, a slurry of the vinyl copolymer (B) is obtained, and then a bead-like vinyl copolymer (B) is obtained through dehydration and drying.

  When the vinyl copolymer (B) is produced by suspension polymerization, a suspension stabilizer may be used. Examples of the suspension stabilizer include inorganic suspension stabilizers such as clay, barium sulfate, and magnesium hydroxide, and organic substances such as polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylamide, and methyl methacrylate / acrylamide copolymer. And suspension stabilizers. Two or more of these may be combined. Of these, organic suspension stabilizers are preferably used from the viewpoint of color tone.

  When manufacturing a vinyl-type copolymer (B) by suspension polymerization method, you may use an initiator and a chain transfer agent as needed. Examples of the initiator and the chain transfer agent include the initiator and the chain transfer agent exemplified in the method for producing the graft copolymer (A).

  When the vinyl copolymer (B) is produced by the suspension polymerization method, there is no particular limitation on the monomer charging method, the initial batch method, a part or all of the monomers are continuously added. Either a charging method or a method in which a part or all of the monomer is divided and charged may be used.

  When the vinyl copolymer (B) is produced by the suspension polymerization method, the polymerization temperature is not particularly limited, but it is easy to adjust the weight average molecular weight and the degree of dispersion of the vinyl copolymer (B) to the above ranges. From the viewpoint of suspension stability, the polymerization is started at 60 to 80 ° C., and the temperature rise is started when the polymerization rate reaches 50 to 70%, and finally the temperature is set to 100 to 120 ° C. preferable. In addition, it is preferable to pressurize the inside of a polymerization tank to 0.3-0.5 MPa with inert gas, such as nitrogen, at the time of temperature rising start.

  The thermoplastic resin composition of the present invention comprises 20 to 40 parts by weight of the graft copolymer (A) and vinyl based on the total of 100 parts by weight of the graft copolymer (A) and the vinyl copolymer (B). It is formed by blending 60 to 80 parts by weight of the copolymer (B). When the graft copolymer (A) exceeds 40 parts by weight and the vinyl copolymer (B) is less than 60 parts by weight, the chemical resistance and rigidity of the molded product are lowered, and yellowing in the dark at the time of chemical contact Is likely to occur. On the other hand, when the graft copolymer (A) is less than 20 parts by weight and the vinyl copolymer (B) exceeds 80 parts by weight, the melt viscosity of the thermoplastic resin composition increases, and the impact resistance of the molded product Sex is reduced.

  In the thermoplastic resin composition of the present invention, the rubber polymer (r) equivalent content in the graft copolymer (A) is preferably 10 to 25% by weight in a total of 100% by weight of the thermoplastic resin composition. . By setting the rubber polymer (r) equivalent to such a range, the chemical resistance and impact resistance of the molded product can be further improved.

  The thermoplastic resin composition of the present invention has an acetone-soluble component (C) having a weight average molecular weight of 150,000 to 250,000, a dispersity of 2.8 or more, and derived from a vinyl cyanide monomer. The content of the unit is 29 to 36% by weight. Here, the vinyl cyanide monomer-derived unit means a structural unit derived from a vinyl cyanide monomer in the copolymer contained in the acetone-soluble component (C). As for chemical resistance, the graft copolymer (A) and vinyl copolymer (B) contained in the molded product are grafted to the rubbery polymer (r) as compared with the graft component having high resistance to chemicals. The influence by the component which is not (acetone soluble part (C)) is large. On the other hand, the component not grafted on the rubber polymer (r) has a relatively high fluidity. Therefore, in the present invention, attention was focused on the acetone-soluble component (C) in the thermoplastic resin composition. Furthermore, in order to improve the chemical resistance of the molded product, it is effective to suppress the penetration of the chemical solution attached to the molded product, specifically, to strengthen the entanglement of molecular chains by increasing the molecular weight, It is effective to enhance the interaction between the molecular chains by improving the intermolecular force by increasing the nitrile. In addition, a vinyl copolymer having a relatively high vinyl cyanide monomer-derived unit content and a relatively low molecular weight, and a relatively high molecular weight vinyl cyanide monomer-derived unit content In the present invention, among the acetone-soluble components (C), vinyl cyanide is used because chemical resistance can be improved while maintaining moldability by using a combination of vinyl copolymers having a low content. Molecular weight of the component (C-1) having a content of the monomer-based unit of 35% by weight or more and the component (C-2) having a content of the vinyl cyanide-based monomer-derived unit of less than 35% by weight Focused on the distribution. Furthermore, the effect | action which reinforce | strengthens the interaction between the molecules which suppress a chemical | medical agent penetration | permeation is show | played effectively, when content of the unit derived from a vinyl cyanide type monomer is 35 weight% or more. On the other hand, the effect of improving the compatibility with the graft copolymer (A) is effectively exhibited when the content of the vinyl cyanide monomer-derived unit is less than 35% by weight. Therefore, in the present invention, focusing on whether the content of the vinyl cyanide monomer-derived unit is 35% by weight or more or less than 35% by weight, the component (C-1) and the component ( C-2) Attention was paid to each molecular weight distribution. That is, 10 to 30% by weight of component (C-1) and 70 to 90% by weight of component (C-2) are contained in 100% by weight of acetone-soluble component (C), and 100% by weight of component (C-1). %, The proportion of components having a molecular weight of 30,000 to 200,000 is 70% by weight or more, the proportion of components having a molecular weight of more than 200,000 is 10 to 20% by weight, and the proportion of components having a molecular weight of less than 30,000 is 20%. The proportion of the component having a molecular weight of 30,000 to 200,000 is 40 to 60% by weight and the proportion of the component having a molecular weight exceeding 200,000 is 20% in 100% by weight of the component (C-2). %, And the proportion of components having a molecular weight of less than 30,000 is 20% by weight or less.

  By setting the weight average molecular weight of the acetone-soluble component (C) to 150,000 or more, impact resistance and chemical resistance of the molded product can be improved, and yellowing in the dark at the time of chemical contact can be reduced. On the other hand, fluidity | liquidity can be improved by making the weight average molecular weight of acetone soluble part (C) into 250,000 or less. 230,000 or less is more preferable.

  By setting the degree of dispersion of the acetone-soluble component (C) to 2.8 or more, the fluidity can be improved. 3.0 or more is more preferable.

  By making the content of the unit derived from vinyl cyanide monomer of acetone-soluble component (C) 29% by weight or more, the chemical resistance, rigidity, and impact resistance of the molded product are improved. Dark yellowing can be reduced. On the other hand, when the content of the unit derived from the vinyl cyanide monomer in the acetone-soluble component (C) is 36% by weight or less, the fluidity, the impact resistance of the molded product, and the color tone can be improved.

  By containing 10% by weight or more of component (C-1) having a content of vinyl cyanide monomer-derived units of 35% by weight or more in 100% by weight of acetone-soluble component (C), Improves chemical properties, rigidity, and impact resistance, and can reduce yellowing in the dark at the time of chemical contact. On the other hand, impact resistance and color tone can be improved by containing 30% by weight or less of component (C-1).

  Further, in 100% by weight of the acetone-soluble component (C), by containing 70% by weight or more of the component (C-2) in which the content of the vinyl cyanide monomer-derived unit is less than 35% by weight, a molded product is obtained. It is possible to improve the impact resistance. On the other hand, by containing 90% by weight or less of the component (C-2), the rigidity and impact resistance of the molded product can be improved.

  Furthermore, when the ratio of the component having a molecular weight of 30,000 to 200,000 is 70% by weight or more in 100% by weight of the component (C-1), fluidity and chemical resistance of the molded product are improved. On the other hand, the proportion of components having a molecular weight of 30,000 to 200,000 is more preferably 80% by weight or less. In addition, if the proportion of the component having a molecular weight exceeding 200,000 is 10% by weight or more in 100% by weight of component (C-1), chemical resistance and impact resistance are improved, and the yellowing in the dark at the time of chemical contact Can be reduced. On the other hand, if the proportion of the component having a molecular weight exceeding 200,000 is 20% by weight or less, the fluidity is improved. Furthermore, if the proportion of the component having a molecular weight of less than 30,000 in 100% by weight of component (C-1) is 20% by weight or less, the chemical resistance of the molded product is improved, and the yellowing in the dark at the time of chemical contact is improved. Can be reduced. 15% by weight or less is more preferable. On the other hand, the proportion of components having a molecular weight of less than 30,000 is more preferably 10% by weight or more.

  If the ratio of the component having a molecular weight of 30,000 to 200,000 is 40 to 60% by weight in 100% by weight of component (C-2), the fluidity and chemical resistance of the molded product are improved, and the chemical contact It is possible to reduce yellowing in the dark in the time. Further, if the proportion of the component having a molecular weight exceeding 200,000 in 100% by weight of component (C-2) is 20% by weight or more, the chemical resistance and impact resistance of the molded product are improved, and darkness at the time of chemical contact The yellowing can be reduced. More preferably 25% by weight or more. On the other hand, the proportion of the component having a molecular weight exceeding 200,000 is more preferably 50% by weight or less. Furthermore, if the proportion of the component having a molecular weight of less than 30,000 in 100% by weight of component (C-2) is 20% by weight or less, the chemical resistance of the molded product is improved, and the yellowing in the dark at the time of chemical contact is improved. Can be reduced. On the other hand, the proportion of components having a molecular weight of less than 30,000 is more preferably 5% by weight or more.

  Here, the component having a molecular weight of less than 30,000 is a component having relatively high fluidity of the component not grafted to the rubbery polymer (r) of the graft copolymer (A), but the content thereof is in the above range. When it is more, the chemical resistance tends to decrease. On the other hand, a component having a molecular weight exceeding 200,000 is a component that contributes to an improvement in chemical resistance. However, if the content in the component (C-2) is more than the above range, the fluidity tends to decrease.

  Here, the weight average molecular weight and the degree of dispersion of the acetone-soluble component (C) in the thermoplastic resin composition were determined by concentrating the filtrate obtained by filtering the acetone-insoluble component from the thermoplastic resin composition with a rotary evaporator. It can be measured in the same manner as the graft copolymer (A) using a solution of about 0.2% by weight in which about 0.03 g of the soluble component (C) is dissolved in about 15 g of tetrahydrofuran.

Here, the content of the vinyl cyanide monomer-derived unit in the acetone-soluble component (C) of the thermoplastic resin composition can be determined by the following composition distribution measurement. First, 5 g of an acetone soluble component (C) collected by concentrating a filtrate obtained by filtering acetone insoluble components from a thermoplastic resin composition using a rotary evaporator is dissolved in 80 ml of acetone. Cyclohexane is gradually added to the obtained solution, and the addition is stopped when it becomes cloudy. This cloudy solution was added to 8000 r. p. After centrifugation at m (10000 G) for 40 minutes, the supernatant is separated to obtain an insoluble matter. The insoluble matter is dried under reduced pressure at 80 ° C. for 5 hours, and its weight is measured. Then, FT-IR analysis was performed on a film with a thickness of 30 ± 5 μm produced by a heat press set at 230 ° C., and the inclusion of vinyl cyanide monomer-derived units from the intensity ratio of the following peak appearing in the FT-IR chart The amount and its weight can be quantified.
Unit derived from aromatic vinyl monomer: 1605 cm ⁻¹ peak attributed to vibration of benzene nucleus Unit derived from vinyl cyanide monomer: 2240 cm ⁻¹ peak attributed to —C≡N stretching Separated supernatant 5 ml of cyclohexane is further added to the liquid, and insoluble matter is obtained from the cloudy liquid by the same method. Repeat the above operation, add cyclohexane in 5 m increments until the cloudiness disappears, and determine the content and weight of insoluble vinyl cyanide monomer-derived units in each cyclohexane addition amount as vinyl cyanide monomer-derived units. It can be measured separately for each content. By the above method, the weights of the component (C-1) having a unit derived from vinyl cyanide monomer of 35% by weight or more and the component (C-2) having a unit of less than 35% by weight are obtained.

  Moreover, about each sample divided according to content of the vinyl cyanide monomer-derived unit, a component having a molecular weight of less than 30,000 is measured by GPC measurement by the same method as described in the vinyl copolymer (B). The weight ratio of components having a molecular weight of 30,000 to 200,000 and components having a molecular weight exceeding 200,000 can be determined.

  In the thermoplastic resin composition of the present invention, for example, the graft copolymer (A) and the high nitrile content described later can be used as the method for bringing the acetone-soluble content (C) into the weight average molecular weight and the degree of dispersion. The method of mix | blending the vinyl copolymer (B) containing a vinyl copolymer (B-1) and a high molecular weight vinyl copolymer (B-2) is mentioned.

  In the thermoplastic resin composition of the present invention, another thermoplastic resin or a thermosetting resin may be further blended within a range that does not impair the object of the present invention. Examples of other thermoplastic resins include polyamide resins, polyphenylene sulfide resins, polyether ether ketone resins, polyester resins such as polylactic acid resins, polysulfone resins, polyether sulfone resins, aromatic or aliphatic polycarbonate resins, polyarylate. Resin, polyphenylene oxide resin, polyacetal resin, polyimide resin, polyetherimide resin, aromatic or aliphatic polyketone resin, fluororesin, polyvinyl chloride resin, polyvinylidene chloride resin, vinyl ester resin, cellulose acetate resin, polyvinyl alcohol Resin etc. are mentioned. Examples of the thermosetting resin include phenol resin, melamine resin, polyester resin, silicone resin, and epoxy resin. Two or more of these may be blended.

  In the thermoplastic resin composition of the present invention, if necessary, glass fiber, glass powder, glass beads, glass flake, alumina, alumina fiber, carbon fiber, graphite fiber, as long as the object of the present invention is not impaired. Inorganic fillers such as stainless fiber, whisker, potassium titanate fiber, wollastonite, asbestos, hard clay, calcined clay, talc, kaolin, mica, calcium carbonate, magnesium carbonate, aluminum oxide and minerals; hindered phenol, sulfur-containing Antioxidants such as compounds or phosphorus-containing organic compounds; heat stabilizers such as phenols and acrylates; UV absorbers such as benzotriazoles, benzophenones, and salicylates; hindered amine light stabilizers; higher fatty acids, acids Esters, acid amides or higher al Lubricants and plasticizers such as montoleic acid; release agents such as montanic acid and salts thereof, esters thereof, half esters thereof, stearyl alcohol, stearamide and ethylene wax; various flame retardants; flame retardant aids; Anti-coloring agents such as phosphites; neutralizing agents such as phosphoric acid, monosodium phosphate, maleic anhydride, and succinic anhydride; nucleating agents; antistatic agents such as amines, sulfonic acids, and polyethers; Colorants such as carbon black, pigments and dyes can be blended.

  Next, the manufacturing method of the thermoplastic resin composition of this invention is demonstrated. The thermoplastic resin composition of the present invention can be obtained, for example, by melt-kneading the aforementioned graft copolymer (A), vinyl copolymer (B) and other components as required. The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and there are a method of mixing each component constituting the thermoplastic resin composition using a mixer, a method of uniformly melting and kneading them. Can be mentioned. Examples of the mixer include a V-type blender, a super mixer, a super floater, and a Henschel mixer. Examples of the melt kneader include a kneader, a single screw or twin screw extruder, and the like. The melt kneading temperature is preferably 210 to 320 ° C, more preferably 230 to 300 ° C. The obtained thermoplastic resin composition is generally used after being pelletized by a pelletizer.

In the method for producing a thermoplastic resin composition of the present invention, as the vinyl copolymer (B), at least 55 to 65% by weight of an aromatic vinyl monomer (b1) and a vinyl cyanide monomer ( b2) A high nitrile-containing vinyl copolymer having a weight average molecular weight of 100,000 to 150,000 (copolymerized with a vinyl monomer mixture ( b-1 ) containing 35 to 45% by weight) B-1), a vinyl-based monomer containing at least 65% by weight of the aromatic vinyl-based monomer (b1) and 75% by weight or less and a vinyl cyanide monomer (b2) of 25% by weight or more and less than 35% by weight It is preferable to combine the monomer mixture ( b-2 ) with a high molecular weight vinyl copolymer (B-2) having a weight average molecular weight of 250,000-350,000.

The content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture ( b-1 ) constituting the high nitrile-containing vinyl copolymer (B-1) is the same as that of the thermoplastic resin composition. From the viewpoint of improving moldability and the color tone of the molded product, 55% by weight or more is preferable and 58% by weight or more is more preferable in the total 100% by weight of the vinyl monomer mixture ( b-1 ). On the other hand, the content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture ( b-1 ) improves the impact resistance and chemical resistance of the molded product, and is a dark place at the time of chemical contact. From the viewpoint of reducing yellowing, it is preferably 65% by weight or less, and more preferably 62% by weight or less.

On the other hand, the content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture ( b-1 ) constituting the high nitrile-containing vinyl copolymer (B-1) depends on the resistance of the molded product. From the viewpoint of improving chemical properties and impact resistance and reducing yellowing in the dark at the time of chemical contact, it is preferably 35% by weight or more, and more preferably 38% by weight or more. On the other hand, the content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture ( b-1 ) is preferably 45% by weight or less from the viewpoint of improving the fluidity and color tone of the molded product, 42% by weight or less is more preferable.

The content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture ( b-2 ) constituting the high molecular weight vinyl copolymer (B-2) depends on the flow of the thermoplastic resin composition. From the viewpoint of improving the properties and the color tone of the molded product, 65% by weight or more is preferable and 68% by weight or more is more preferable in the total 100% by weight of the vinyl monomer mixture ( b-2 ). On the other hand, the content of the aromatic vinyl monomer (b1) in the vinyl monomer mixture ( b-2 ) improves the impact resistance and chemical resistance of the molded product, and is a dark place at the time of chemical contact. From the viewpoint of reducing yellowing, 75% by weight or less is preferable, and 72% by weight or less is more preferable.

On the other hand, the content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture ( b-2 ) constituting the high molecular weight vinyl copolymer (B-2) is determined by the thermoplastic resin composition. From the viewpoint of improving impact resistance and chemical resistance of an object and reducing yellowing in the dark at the time of chemical contact, it is preferably 25% by weight or more, and more preferably 27% by weight or more. On the other hand, the content of the vinyl cyanide monomer (b2) in the vinyl monomer mixture ( b-2 ) is preferably 34% by weight or less from the viewpoint of improving the impact resistance and color tone of the molded product, 30% by weight or less is more preferable.

  In the method for producing a thermoplastic resin composition of the present invention, the weight average molecular weight of the high nitrile-containing vinyl copolymer (B-1) is 100,000 to 150,000. If the weight average molecular weight of the high nitrile-containing vinyl copolymer (B-1) is 100,000 or more, chemical resistance can be improved and dark yellowing at the time of chemical contact can be reduced. On the other hand, if the weight average molecular weight of the high nitrile-containing vinyl copolymer (B-1) is 150,000 or less, the fluidity is improved.

  Moreover, in the manufacturing method of the thermoplastic resin composition of this invention, the weight average molecular weights of a high molecular weight vinyl type copolymer (B-2) are 250,000-350,000. If the weight average molecular weight of the high molecular weight vinyl copolymer (B-2) is 250,000 or more, chemical resistance is improved, and yellowing in the dark at the time of chemical contact can be reduced. On the other hand, if the weight average molecular weight of the high molecular weight vinyl copolymer (B-2) is 350,000 or less, the fluidity is improved.

  By setting the weight average molecular weights of the high nitrile-containing vinyl copolymer (B-1) and the high molecular weight vinyl copolymer (B-2) within the above range, the acetone-soluble component (C ) Can be easily adjusted to the above desired range.

  The degree of dispersion of the high nitrile-containing vinyl copolymer (B-1) and the high molecular weight vinyl copolymer (B-2) is not particularly limited, but is preferably 2.0 to 3.0. When the degree of dispersion is in the above range, the fluidity and chemical resistance can be further improved, and yellowing in the dark place during chemical contact can be further reduced.

  A high nitrile-containing vinyl copolymer (B-1) having a weight average molecular weight of 100,000 to 150,000 and a high molecular weight vinyl copolymer having a weight average molecular weight of 250,000 to 350,000 (B- 2) can be easily produced, for example, by using the above-mentioned initiator or chain transfer agent, or setting the polymerization temperature within the above-mentioned preferred range.

  In the method for producing the thermoplastic resin composition of the present invention, the above-mentioned high nitrile-containing vinyl copolymer (B-1) and high molecular weight vinyl copolymer (B-2) are converted into (B-1) / It is more preferable to combine at (B-2) = 33/67 to 67/33 (weight ratio). By setting (B-1) / (B-2) to 33/67 or more, chemical resistance and impact resistance can be further improved, and yellowing in the dark at the time of chemical contact can be further reduced. On the other hand, by setting (B-1) / (B-2) to 67/33 or less, impact resistance and color tone can be further improved.

  The thermoplastic resin composition of the present invention can be molded by any molding method. Examples of the molding method include injection molding, extrusion molding, inflation molding, blow molding, vacuum molding, compression molding, gas assist molding, and the like, and injection molding is preferably used. The cylinder temperature during injection molding is preferably 210 to 320 ° C, and the mold temperature is preferably 30 to 80 ° C.

  The thermoplastic resin composition of the present invention can be widely used as a molded article having an arbitrary shape. Examples of the molded article include films, sheets, fibers, cloths, nonwoven fabrics, injection molded articles, extruded molded articles, vacuum / pressure molded articles, blow molded articles, and composites with other materials. The molded article of the present invention is useful for applications such as home appliances, communication-related equipment, general goods, and medical-related equipment, and can be preferably used for exterior parts that are in contact with detergents and solvents.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. First, the evaluation method in an Example is demonstrated.

(1) Weight average particle diameter of rubbery polymer The rubbery polymer latex is diluted and dispersed in an aqueous medium, and the particle size distribution is measured by a laser scattering diffraction particle size distribution analyzer “LS 13 320” (Beckman Coulter, Inc.). Was measured. From the particle size distribution, the weight average particle size of the rubber polymer (r) was calculated.

(2) Graft ratio of graft copolymer (A) 80 ml of acetone is added to about 1 g (m: sample weight) of the graft copolymer (A) and refluxed in a 70 ° C. water bath for 3 hours. 8000 r. p. After centrifugation at m (10000 G) for 40 minutes, the insoluble matter was filtered. The obtained acetone insoluble matter was dried under reduced pressure at 80 ° C. for 5 hours, its weight (n) was measured, and the graft ratio was calculated from the following formula. Here, X is the rubbery polymer content (%) of the graft copolymer (A).
Graft ratio (%) = {[(n) − (m) × X] / [(m) × X]} × 100.

  Moreover, it obtained by concentrating acetone soluble part with a rotary evaporator.

(3) Weight average molecular weight and degree of dispersion The acetone-soluble content of the graft copolymer (A) was obtained by the operation of (2). Further, 80 ml of acetone was added to about 1 g (m: sample mass) of the thermoplastic resin composition pellets obtained in each example and comparative example, and the mixture was refluxed in a 70 ° C. hot water bath for 3 hours. p. After centrifuging at m (10000 G) for 40 minutes, the insoluble matter was filtered to obtain an acetone-soluble matter (C) of the thermoplastic resin composition. About 0.03 g of each of the acetone-soluble content of the graft copolymer (A), the vinyl copolymer (B), and the acetone-soluble content (C) of the thermoplastic resin composition was dissolved in about 15 g of tetrahydrofuran, An approximately 0.2% by weight solution was prepared. From the GPC chromatogram measured under the following conditions, the weight average molecular weight and the degree of dispersion in terms of polystyrene were calculated.
Equipment: Waters 2695
Column temperature: 40 ° C
Detector: RI2414 (differential refractometer)
Carrier eluent flow rate: 0.3 ml / min (solvent: tetrahydrofuran)
Column: TSKgel SuperHZM-M (6.0 mm ID × 15 cm), TSKgel SuperHZM-N (6.0 mm ID × 15 cm) in series (both Tosoh).

(4) Content of unit derived from vinyl cyanide monomer in acetone-soluble component (C) of thermoplastic resin composition Acetone-soluble component of thermoplastic resin composition obtained by operation of (3) above ( C) was heated and pressurized with a heating press set at 230 ° C. to produce a film with a thickness of 30 ± 5 μm. The obtained film was subjected to FT-IR analysis, and the content of vinyl cyanide monomer-derived units (acrylonitrile monomer-derived units) was determined from the intensity ratio of the following peaks appearing on the FT-IR chart.
Unit derived from aromatic vinyl monomer: 1605 cm ⁻¹ peak attributed to vibration of benzene nucleus Vinyl cyanide monomer derived unit: peak at 2240 cm ⁻¹ attributed to —C≡N stretching.

(5) Composition distribution and molecular weight distribution of acetone-soluble component (C) of thermoplastic resin composition The filtrate obtained by filtering the acetone-insoluble component from the thermoplastic resin composition pellets obtained in each Example and Comparative Example was removed with a rotary evaporator. Cyclohexane is gradually added to a solution obtained by dissolving 5 g of acetone-soluble component (C) collected by concentration in 80 ml of acetone, and the addition is stopped when the solution becomes cloudy. This cloudy solution was added to 8000 r. p. After centrifugation at m (10000 G) for 40 minutes, the supernatant was separated to obtain an insoluble matter. The insoluble matter was dried under reduced pressure at 80 ° C. for 5 hours, and its weight was measured. Thereafter, a film with a thickness of 30 ± 5 μm was produced by a heating press set at 230 ° C., and the obtained film was subjected to FT-IR analysis, and from the intensity ratio of the following peak appearing on the FT-IR chart, The content of the monomer-derived unit (acrylonitrile monomer-derived unit) and its weight were quantified.
Unit derived from aromatic vinyl monomer: 1605 cm ⁻¹ peak attributed to vibration of benzene nucleus Vinyl cyanide monomer derived unit: peak at 2240 cm ⁻¹ attributed to —C≡N stretching

  5 ml of cyclohexane was further added to the separated supernatant, and insoluble matter was obtained from the cloudy solution by the same method. Repeat the above operation, add cyclohexane in 5 m increments until the cloudiness disappears, and determine the content and weight of insoluble vinyl cyanide monomer-derived units in each cyclohexane addition amount as vinyl cyanide monomer-derived units. It was measured separately for each content. By the said method, the content of the component (C-1) whose content of an acrylonitrile monomer origin unit is 35 weight% or more and the component (C-2) less than 35 weight% was calculated | required.

  Further, for each sample divided by the content of the vinyl cyanide monomer-derived unit, GPC measurement was performed by the same method as described in the above (3), a component having a molecular weight of less than 30,000, The weight ratio of 200,000 components and components exceeding 200,000 molecular weight was determined.

(6) Impact resistance (Charpy impact strength)
SE-50DU manufactured by Sumitomo Heavy Industries, Ltd. in which the thermoplastic resin composition pellets obtained in each Example and Comparative Example were dried in a hot air dryer at 80 ° C. for 3 hours and then the cylinder temperature was set to 230 ° C. The molding machine was filled and a 4 mm thick dumbbell specimen was immediately molded. About five obtained dumbbell test pieces, Charpy impact strength was measured by a method based on ISO179, and the number average value was calculated.

(7) Rigidity (flexural modulus)
SE-50DU manufactured by Sumitomo Heavy Industries, Ltd. in which the thermoplastic resin composition pellets obtained in each Example and Comparative Example were dried in a hot air dryer at 80 ° C. for 3 hours and then the cylinder temperature was set to 230 ° C. The molding machine was filled and a 4 mm thick dumbbell specimen was immediately molded. For each of the three obtained dumbbell test pieces, the flexural modulus was measured by a method based on ISO178, and the number average value was calculated.

(8) Fluidity (melt flow rate (MFR))
After the thermoplastic resin composition pellets obtained in each Example and Comparative Example were dried in a hot air dryer at 80 ° C. for 3 hours, MFR was measured by a method based on ISO 113 under the conditions of a measurement temperature of 220 ° C. and a load of 98 N. It was measured.

(9) Chemical resistance Sumitomo Heavy Industries, Ltd., in which the thermoplastic resin composition pellets obtained in each Example and Comparative Example were dried in a hot air dryer at 80 ° C. for 3 hours, and then the cylinder temperature was set to 230 ° C. The product was filled into a SE-50DU molding machine, and a dumbbell specimen having a thickness of 4 mm was formed.

For two dumbbell test pieces, half of the dumbbell test piece 3 having the weld portion 4 was set in a jig as shown in FIG. 1 in an environment of a temperature of 23 ° C. and a humidity of 50%. Next, isopropanol 2 was dropped into the weld portion 4 using the dropper 1 while applying a load to the end face of the dumbbell test piece 3 having the weld portion 4 with a weight 5 having a weight of 1 kg, and allowed to stand for 24 hours. After standing, the presence or absence of fracture of the weld portion was observed by visual observation, and evaluated according to the following criteria.
When the weld part does not break in both: ○
If even one weld breaks: x.

(10) Dark yellowing at the time of chemical contact After the thermoplastic resin composition pellets obtained by the respective examples and comparative examples were dried in a hot air dryer at 80 ° C. for 3 hours, the cylinder temperature was set to 230 ° C. The plate was filled into a SE-50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd., and a plate test piece having a length of 50 mm, a width of 30 mm, and a thickness of 3 mm was molded. About the obtained plate test piece, L *, a *, and b * were measured using CCM (Spectrophotometer Macbeth 7000A) by Sumika Color Co., Ltd., respectively.

  Further, the plate test piece was immersed in “Nanox” kept at 50 ° C., allowed to stand for 24 hours, and then irradiated with light using an open frame carbon arc lamp type light resistance tester (black panel temperature 63 ° C.) for 24 hours. Next, after standing for 24 hours in a constant temperature and humidity chamber with a temperature of 80 ° C. and a humidity of 80%, using a CCM (Spectrophotometer Macbeth 7000A) manufactured by Sumika Color Co., Ltd. It was measured. ΔE * was calculated from the measured values of L *, a *, and b * before and after the test.

(Reference Example 1) Graft copolymer (A- (1))
In a 5 liter four-necked flask equipped with a stirring blade, 31.5 parts by weight of polybutadiene latex (rubber weight average particle diameter 0.30 μm, gel content 85%) (solid content conversion), styrene-butadiene rubber Latex (rubber weight average particle size 1.0 μm, gel-free) 13.5 parts by weight (in terms of solid content), pure water 130 parts by weight, sodium laurate 0.4 parts by weight, glucose 0.2 parts by weight, pyrroline Sodium sulfate 0.2 parts by weight, ferrous sulfate 0.01 parts by weight, after substitution with nitrogen, the temperature was adjusted to 60 ° C., with stirring, 5.84 parts by weight of styrene, 2.16 parts by weight of acrylonitrile and t -Initial addition of 0.083 parts by weight of monomer mixture of dodecyl mercaptan over 30 minutes.

  Subsequently, 0.12 parts by weight of cumene hydroperoxide, 1.8 parts by weight of sodium laurate as an emulsifier, and 25 parts by weight of pure water were continuously added dropwise over 4 hours. At the same time, a monomer mixture of 34.26 parts by weight of styrene, 12.74 parts by weight of acrylonitrile and 0.483 parts by weight of t-dodecyl mercaptan was continuously added dropwise over 4 hours. After the monomer mixture was added dropwise, an initiator mixture of cumene hydroperoxide 0.08 parts by weight, emulsifier sodium laurate 0.3 parts by weight and pure water 25 parts by weight was added over 2 hours to polymerize. Was terminated. The obtained graft copolymer latex was coagulated with 1.5% by weight sulfuric acid, neutralized with sodium hydroxide, washed, centrifuged and dried to obtain a powdered graft copolymer (A- (1) ) The graft ratio of the obtained graft copolymer (A- (1)) was 24%. The weight average molecular weight of the acetone-soluble component is 80,000, the degree of dispersion of the acetone-soluble component is 2.2, and the content of the acetone-soluble component derived from the vinyl cyanide monomer is 27. % By weight.

(Reference Example 2) Graft copolymer (A- (2))
In a 5 liter four-necked flask equipped with a stirring blade, 50 parts by weight of polybutadiene latex (rubber weight average particle diameter 0.30 μm, gel content 85%) (solid content conversion), 130 parts by weight of pure water, Charge 0.4 parts by weight of sodium laurate, 0.2 parts by weight of glucose, 0.2 parts by weight of sodium pyrophosphate, 0.01 parts by weight of ferrous sulfate, and after nitrogen replacement, adjust the temperature to 60 ° C. and stir. However, a monomer mixture of 6.7 parts by weight of styrene, 2.5 parts by weight of acrylonitrile and 0.058 parts by weight of t-dodecyl mercaptan was initially added over 30 minutes.

  Subsequently, an initiator mixture of 0.32 parts by weight of cumene hydroperoxide, 1.5 parts by weight of sodium laurate as an emulsifier and 25 parts by weight of pure water was continuously dropped over 5 hours. At the same time, a monomer mixture of 29.8 parts by weight of styrene, 11.0 parts by weight of acrylonitrile and 0.193 parts by weight of t-dodecyl mercaptan was continuously added dropwise over 3 hours. After dropping of the monomer mixture, only the initiator mixture was continuously dropped for 2 hours, and then the polymerization was terminated. The obtained graft copolymer latex was coagulated with 1.5% by weight sulfuric acid, neutralized with sodium hydroxide, washed, centrifuged and dried to obtain a powdered graft copolymer (A- (2) ) The graft ratio of the obtained graft copolymer (A- (2)) was 38%. The acetone-soluble component has a weight average molecular weight of 83,000, the acetone-soluble component has a dispersity of 2.3, and the acetone-soluble vinyl cyanide monomer-derived unit content is 27. % By weight.

(Reference Example 3) Graft copolymer (A- (3))
Except that t-dodecyl mercaptan in the monomer mixture to be initially added is 0.01 parts by weight and t-dodecyl mercaptan in the monomer mixture added in parallel after the start of polymerization is 0.04 parts by weight. A graft copolymer (A- (3)) was obtained in the same manner as in Reference Example 1. The graft ratio of the obtained graft copolymer (A- (3)) was 50%. The weight average molecular weight of the acetone-soluble component is 300,000, the degree of dispersion of the acetone-soluble component is 2.4, and the content of the unit derived from the vinyl cyanide monomer based on the acetone-soluble component is 27. % By weight.

(Reference Example 4) Graft copolymer (A- (4))
In the monomer mixture to be initially added, 3.6 parts by weight of styrene, 0.6 part by weight of acrylonitrile, 0.15 part by weight of t-dodecyl mercaptan, and 10.8 parts by weight of methyl methacrylate were added. Initial addition was performed in the same manner as in Reference Example 1 except that these monomer mixtures were added over 45 minutes.

  Subsequently, an initiator mixture of 0.3 parts by weight of cumene hydroperoxide, 1.6 parts by weight of sodium laurate as an emulsifier and 25 parts by weight of pure water was continuously dropped over 5 hours. At the same time, a monomer mixture of 8.4 parts by weight of styrene, 1.4 parts by weight of acrylonitrile, 25.2 parts by weight of methyl methacrylate and 0.36 parts by weight of t-dodecyl mercaptan was continuously added dropwise over 5 hours. did. A graft copolymer (A- (4)) was obtained in the same manner as in Reference Example 2 except that the monomer mixture was added dropwise and the polymerization was terminated by maintaining for 1 hour. The graft ratio of the obtained graft copolymer (A- (4)) was 47%. Moreover, the weight average molecular weight of the acetone soluble part was 78,000, and the dispersion degree of the acetone soluble part was 2.2. In other words, the content of the acetone-soluble vinyl cyanide monomer-derived unit was 5% by weight.

  The graft copolymers (A) prepared according to Reference Examples 1 to 4 are shown together in Table 1.

(Reference Example 5) Vinyl-based copolymer (B- (1))
First, as a medium for suspension polymerization, a methyl methacrylate-acrylamide copolymer was produced by the following method.

  80 parts by weight of acrylamide, 20 parts by weight of methyl methacrylate, 0.3 part by weight of potassium persulfate, and 1800 parts by weight of ion-exchanged water were charged into the reactor, and the gas phase in the reactor was replaced with nitrogen gas. While stirring well, the temperature was maintained at 70 ° C., and the polymerization was terminated when the polymerization rate reached 99% to obtain an aqueous solution of acrylamide and methyl methacrylate binary copolymer. The resulting aqueous solution had a slightly cloudy viscosity. To this aqueous solution, 35 parts by weight of sodium hydroxide and 15000 parts by weight of ion-exchanged water were added to obtain a 0.6% by weight aqueous solution of a binary copolymer of acrylamide and methyl methacrylate. After saponification by stirring at 70 ° C. for 2 hours, the mixture was cooled to room temperature to obtain an aqueous solution of a transparent suspension polymerization medium (methyl methacrylate-acrylamide binary copolymer).

  In a 20 L autoclave, 6 parts by weight of the aqueous methyl methacrylate-acrylamide binary copolymer solution and 150 parts by weight of pure water were added and stirred at 400 rpm, and the system was replaced with nitrogen gas. After the temperature was raised to 70 ° C., 41.8 parts by weight of acrylonitrile, 3.8 parts by weight of styrene, 0.034 parts by weight of azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) A monomer mixture of 293 parts by weight and 0.44 parts by weight of t-dodecyl mercaptan was added over 30 minutes with stirring to initiate the polymerization reaction. When 15 minutes, 40 minutes, 65 minutes, and 85 minutes had elapsed after the addition of the monomer mixture, 4.0 parts by weight of styrene was added each time four times using a feed pump. Further, 95 minutes after the addition of the monomer mixture, 38.4 parts by weight of styrene was added to the autoclave using a feed pump. After all the monomers were added, the temperature was raised to 100 ° C. over 60 minutes. When the temperature reached 80 ° C., the inside of the autoclave was pressurized to 0.3 MPa with nitrogen gas. After reaching 100 ° C, the temperature was maintained at 100 ° C for 30 minutes, and then cooling, polymer separation, washing, and drying were performed to obtain a bead-shaped vinyl copolymer (B- (1)). The resulting vinyl copolymer (B- (1)) had a weight average molecular weight of 110,000, a dispersity of 2.1, and a vinyl cyanide monomer-derived unit content of 36% by weight. .

(Reference Example 6) Vinyl-based copolymer (B- (2))
A 20 L autoclave was charged with 6 parts by weight of a methyl methacrylate-acrylamide binary copolymer aqueous solution obtained in Reference Example 5 and 150 parts by weight of pure water, stirred at 400 rpm, and the system was replaced with nitrogen gas. After the temperature was raised to 70 ° C., 28.9 parts by weight of acrylonitrile, 11.1 parts by weight of styrene, 0.32 parts by weight of azobisisobutyronitrile, 0.063 parts by weight of t-dodecyl mercaptan and 0.094 of n-octyl mercaptan Part by weight of the monomer mixture was added over 30 minutes with stirring to initiate the polymerization reaction. After 1 hour from the addition of the monomer mixture, 15 parts by weight of styrene was added using a feed pump. Thereafter, styrene was added to the autoclave three times, 15 parts by weight per time, at intervals of 30 minutes. After all the monomers were added, the temperature was raised to 100 ° C. over 60 minutes. When the temperature reached 80 ° C., the inside of the autoclave was pressurized to 0.3 MPa with nitrogen gas. After reaching 100 ° C., the temperature was maintained at 100 ° C. for 30 minutes, and then cooling, polymer separation, washing, and drying were performed to obtain a bead-shaped vinyl copolymer (B- (2)). The resulting vinyl copolymer (B- (2)) had a weight average molecular weight of 320,000, a degree of dispersion of 2.8, and a content of vinyl cyanide monomer-derived units of 27% by weight. .

Reference Example 7 Vinyl-based copolymer (B- (3))
A vinyl copolymer (B- (3)) was obtained in the same manner as in Reference Example 5 except that t-dodecyl mercaptan in the monomer mixture was changed to 0.75 parts by weight. The obtained vinyl copolymer (B- (3)) had a weight average molecular weight of 54,000, a degree of dispersion of 2.1, and a content of vinyl cyanide monomer-derived units of 36% by weight. .

(Reference Example 8) Vinyl-based copolymer (B- (4))
The monomer mixture to be added initially was 44 parts by weight of acrylonitrile, 3.8 parts by weight of styrene, 0.034 parts by weight of azobisisobutyronitrile, and 2,2′-azobis (2,4-dimethylvaleronitrile). Reference Example 5 except that 293 parts by weight and 0.75 parts by weight of t-dodecyl mercaptan were added, and the amount of styrene added was changed to 36.2 parts by weight when 95 minutes had elapsed after the addition of the monomer mixture. In the same manner as above, a vinyl copolymer (B- (4)) was obtained. The obtained vinyl copolymer (B- (4)) had a weight average molecular weight of 55,000, a degree of dispersion of 2.1, and a content of vinyl cyanide monomer-derived units of 40% by weight. .

Reference Example 9 Vinyl copolymer (B- (5))
The vinyl copolymer (B- (5)) was prepared in the same manner as in Reference Example 6 except that 0.32 parts by weight of t-dodecyl mercaptan of the monomer mixture to be initially added was added and n-octyl mercaptan was not added. ) The resulting vinyl copolymer (B- (5)) had a weight average molecular weight of 130,000, a dispersity of 2.1, and a vinyl cyanide monomer-derived unit content of 27% by weight. .

Reference Example 10 Vinyl copolymer (B- (6))
A vinyl copolymer (B- (6)) was obtained in the same manner as in Reference Example 6 except that t-dodecyl mercaptan and n-octyl mercaptan as the monomer mixture to be initially added were not added. The obtained vinyl copolymer (B- (6)) had a weight average molecular weight of 320,000, a dispersity of 2.9, and a content of vinyl cyanide monomer-derived units of 27% by weight. .

(Reference Example 11) Vinyl-based copolymer (B- (7))
A 20 L autoclave was charged with 6 parts by weight of a methyl methacrylate-acrylamide binary copolymer aqueous solution obtained in Reference Example 5 and 150 parts by weight of pure water, stirred at 400 rpm, and the system was replaced with nitrogen gas. After heating up to 70 ° C., a monomer mixture of 12 parts by weight of acrylonitrile, 9 parts by weight of styrene, 29 parts by weight of methyl methacrylate, 0.3 parts by weight of azobisisobutyronitrile and 0.4 parts by weight of t-dodecyl mercaptan Was added over 30 minutes with stirring to initiate the polymerization reaction. When 60 minutes had elapsed after the addition of the monomer mixture, 2 parts by weight of styrene and 13 parts by weight of methyl methacrylate were added using a feed pump. After 30 minutes, 4 parts by weight of styrene and 11 parts by weight of methyl methacrylate were added to the autoclave. Thirty minutes later, 7 parts by weight of styrene and 13 parts by weight of methyl methacrylate were added to the autoclave. After all the monomer mixture was added, the temperature was raised to 100 ° C. over 120 minutes. When the temperature reached 80 ° C., the inside of the autoclave was pressurized to 0.3 MPa with nitrogen gas. After reaching 100 ° C., the temperature was maintained at 100 ° C. for 30 minutes, and then cooling, polymer separation, washing, and drying were performed to obtain a bead-shaped vinyl copolymer (B- (7)). The resulting vinyl copolymer (B- (7)) had a weight average molecular weight of 140,000, a dispersity of 2.4, and a vinyl cyanide monomer-derived unit content of 12% by weight. .

Reference Example 12 Vinyl copolymer (B- (8))
A 20 L autoclave was charged with 6 parts by weight of a methyl methacrylate-acrylamide binary copolymer aqueous solution obtained in Reference Example 5 and 150 parts by weight of pure water, stirred at 400 rpm, and the system was replaced with nitrogen gas. After heating up to 70 ° C., a monomer mixture of 30 parts by weight of acrylonitrile, 18 parts by weight of styrene, 0.3 part by weight of azobisisobutyronitrile and 0.5 part by weight of t-dodecyl mercaptan was stirred for 30 minutes. The polymerization reaction was started. Thirty minutes after the addition of the monomer mixture, 12 parts by weight of methyl methacrylate was added using a feed pump. Thereafter, at 30 minute intervals, 20 parts by weight of methyl methacrylate was added to the autoclave twice in total. After all the monomers were added, the temperature was raised to 100 ° C. over 60 minutes. When the temperature reached 80 ° C., the inside of the autoclave was pressurized to 0.3 MPa with nitrogen gas. After reaching 100 ° C., the temperature was maintained at 100 ° C. for 30 minutes, and then cooling, polymer separation, washing, and drying were performed to obtain a bead-shaped vinyl copolymer (B- (8)). The obtained vinyl copolymer (B- (8)) had a weight average molecular weight of 115,000, a degree of dispersion of 2.4, and a content of vinyl cyanide monomer-derived units of 30% by weight. .

Reference Example 13 Vinyl copolymer (B- (9))
A 20 L autoclave was charged with 6 parts by weight of a methyl methacrylate-acrylamide binary copolymer aqueous solution obtained in Reference Example 5 and 165 parts by weight of pure water, stirred at 400 rpm, and the system was replaced with nitrogen gas. After raising the temperature to 70 ° C., a monomer mixture of 4 parts by weight of acrylonitrile, 24 parts by weight of styrene, 72 parts by weight of methyl methacrylate, 0.4 parts by weight of azobisisobutyronitrile and 0.01 parts by weight of t-dodecyl mercaptan Was added over 30 minutes with stirring to initiate the polymerization reaction. Polymerization was continued at 70 ° C. and normal pressure for 5 hours, followed by cooling, polymer separation, washing, and drying to obtain a bead-shaped vinyl copolymer (B- (9)). The resulting vinyl copolymer (B- (9)) had a weight average molecular weight of 300,000, a degree of dispersion of 2.7, and a content of vinyl cyanide monomer-derived units of 5% by weight. .

In addition, the materials used in the examples and comparative examples are as follows.
Ethylene / carbon monoxide / (meth) acrylic acid ester copolymer: “Elvalloy” (registered trademark) HP-4051 manufactured by Mitsui DuPont Polychemical Co., Ltd.
Hindered amine light stabilizer: bis (2,2,6,6, -tetramethyl-4-pipedinyl) sebacate "ADEKA STAB" (registered trademark) LA-57 manufactured by ADEKA Corporation
Phosphorus antioxidant: Distearyl pentaerythritol diphosphite “ADEKA STAB” PEP-8 manufactured by ADEKA Corporation
Benzotriazole UV absorber: 2- (2-hydroxy-5-methylphenyl) benzotriazole “Biosorb” 520 manufactured by Kyodo Pharmaceutical Co., Ltd.
(Examples 1-6, Comparative Examples 1-10)
The graft copolymer (A) prepared in Reference Examples 1 to 4 and the vinyl copolymer (B) prepared in Reference Examples 5 to 13 were blended at the blending ratios shown in Tables 3 to 5, respectively. After adding 0.3 parts by weight of t-butylhydroxytoluene and 0.3 parts by weight of tri (nonylphenyl) phosphite as additives, the mixture was mixed at 23 ° C. with a Henschel mixer, and the resulting mixture was extruded by a 40 mmφ extruder. Extruded into a gut at a temperature of 230 ° C. and pelletized. The obtained pellets were injection-molded at a molding temperature of 230 ° C. and a mold temperature of 40 ° C. to prepare test pieces for evaluation. Each physical property was measured by the said method using the obtained test piece.

(Comparative Example 11)
The graft copolymer (A) prepared in Reference Example 1 and the vinyl copolymer (B) prepared in Reference Example 9 were blended in the blending ratios shown in Table 5, respectively, and “Elvalloy” HP-4051 was further blended. 5 parts by weight, 0.5 part by weight of “Adeka Stub” LA-57, 0.45 part by weight of “Adekastab” PEP-8, 0.6 part by weight of “Biosorb” 520, and after mixing at 23 ° C. with a Henschel mixer, The obtained mixture was extruded into a gut shape at an extrusion temperature of 230 ° C. by a 40 mmφ extruder and pelletized. The obtained pellets were injection-molded at a molding temperature of 230 ° C. and a mold temperature of 40 ° C. to prepare test pieces for evaluation. Each physical property was measured by the said method using the obtained test piece.

  The result of the Example and comparative example which were obtained by each Example and comparative example is shown to Tables 3-5.

  The thermoplastic resin compositions of Examples 1 to 6 are excellent in fluidity. In addition, the molded product has excellent chemical resistance and impact resistance, and can reduce yellowing in the dark at the time of chemical contact.

1: Dropper 2: Isopropanol (chemical)
3: Dumbbell specimen 4: Weld part 5: Weight (1 kg)
6: Chemical resistance test jig

Claims (3)

A vinyl monomer containing at least 60 to 80% by weight of an aromatic vinyl monomer (a1) and 20 to 40% by weight of a vinyl cyanide monomer (a2) in the presence of the rubber polymer (r). 20 to 40 parts by weight of graft copolymer (A) obtained by graft copolymerization of body mixture (a) contains at least aromatic vinyl monomer (b1) and vinyl cyanide monomer (b2) A method for producing a thermoplastic resin composition comprising 60 to 80 parts by weight of a vinyl copolymer (B) obtained by copolymerizing a vinyl monomer mixture (b).
The vinyl copolymer (B) contains at least an aromatic vinyl monomer (b1) of 55 to 65% by weight and a vinyl cyanide monomer (b2) of 35 to 45% by weight. becomes the body mixture (b-1) copolymerizing, high nitrile-containing vinyl copolymer having a weight average molecular weight is 100,000～150,000 and (B-1), at least an aromatic vinyl monomer (B1) copolymerized vinyl monomer mixture ( b-2 ) containing more than 65% by weight and 75% by weight or less and vinyl cyanide monomer (b2) containing 25% by weight or more and less than 35% by weight And a method for producing a thermoplastic resin composition in combination with a high molecular weight vinyl copolymer (B-2) having a weight average molecular weight of 250,000 to 350,000. A composition ratio (weight ratio) of the high nitrile-containing vinyl copolymer (B-1) and the high molecular weight vinyl copolymer (B-2) constituting the vinyl copolymer (B), The method for producing a thermoplastic resin composition according to claim 1 , wherein (B-1) / (B-2) = 33/67 to 67/33. The process according to claim 1 or 2 obtained by molding the thermoplastic resin composition obtained by the process according moldings.

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