JP6041381B2 - Thermoplastic resin composition for vehicle lamp and molded product - Google Patents

Description

  The present invention is not only excellent in the performance balance required as a resin composition for vehicle lamps such as impact resistance, fluidity, weather resistance, etc., but also in vapor deposition appearance and tapping strength at the time of mounting, particularly in a low temperature environment. The present invention relates to an excellent thermoplastic resin composition for vehicle lamps and a molded article obtained from the resin composition.

  In general, a vehicular lamp is a structure in which a lens is mounted so as to cover a front opening of a lamp housing having a reflector, and a light source bulb is installed in a lamp chamber surrounded by the lamp housing and the lens. . Usually, the vehicular lamp is fixed to a tapping boss formed on the back side of the lamp housing by bolting via a vehicle body.

  In such a vehicular lamp, in order to effectively reflect the light emitted from the light source bulb, the inner surface of the lamp housing is generally subjected to silver paint or aluminum deposition to act as a reflecting surface of the reflector. However, in order to improve the productivity due to the problem caused by the organic solvent and the simplification of the manufacturing process, the paint removal and the undercoat treatment process are omitted (so-called direct vapor deposition). Thereby, in order to express high brightness as a reflector, the smoothness of the product surface is regarded as important as a resin material constituting the lamp housing.

  In general, the lamp housing and lens parts are joined by melting the resin by various welding methods. However, it is necessary to secure a certain level of welding strength, and the appearance during welding is emphasized. There is a need for a technique that does not generate (molten resin residue).

  For example, Patent Documents 1 to 3 have been proposed for resin compositions having performance required for these vehicular lamps.

JP 2000-276909 A

JP 2005-112991 A

JP 2001-253990 A

  However, even if it is comprised with the resin composition provided with the performance required as a vehicle lamp like these patent documents 1-3, when tapping strength at the time of attaching to a vehicle body is inadequate, at the time of bolt fastening There is a problem that the tapping boss is broken or the lamp is dropped due to insufficient strength when tightening the bolt. Particularly in cold districts, such a malfunction is likely to occur, and there is a demand for a resin material for vehicle lamps having sufficient tapping strength.

  The object of the present invention is not only excellent in the performance balance required as a resin composition for vehicle lamps, such as impact resistance, fluidity, and weather resistance, but also the appearance of vapor deposition and the tapping strength at the time of attachment, particularly tapping in a low temperature environment. An object is to provide a thermoplastic resin composition for vehicle lamps having excellent strength and a molded product obtained from the resin composition.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that the composite rubber having a specific polymer structure is a single monomer such as a vinyl cyanide monomer or an aromatic vinyl monomer. The inventors have found that the above object can be achieved by using a graft copolymer obtained by polymerizing a body mixture, and have reached the present invention.

That is, the present invention relates to a thermoplastic resin composition (graft copolymer (A) and copolymer (20) comprising 20 to 70 parts by weight of graft copolymer (A) and 30 to 80 parts by weight of copolymer (B). The total of B) is 100 parts by weight), and the graft copolymer (A) is composed of 5 to 50% by weight of the conjugated diene rubbery polymer and 50 to 95% by weight of the crosslinked acrylate polymer. the composite rubber 10-80 parts by weight having a core-shell structure, the vinyl cyanide-based monomer, a monomer 20 to 90 parts by weight of at least one selected aromatic vinyl monomer or found by graft-polymerizing The number of particles of the composite rubber having a circle equivalent particle diameter of 150 nm or less with respect to the composite rubber present in the graft copolymer is 20% or less of the total composite rubber particles. And a copolymer B) is a copolymer obtained by copolymerizing an aromatic vinyl monomer, a vinyl cyanide monomer, and other vinyl monomers that can be copolymerized if necessary. The present invention relates to a thermoplastic resin composition for vehicle lamps.

  According to the present invention, not only is it excellent in the performance balance necessary as a resin composition for vehicle lamps such as impact resistance, fluidity, and weather resistance, but also the appearance of vapor deposition and the tapping strength at the time of mounting, especially the tapping strength in a low temperature environment. An excellent thermoplastic resin composition for vehicle lamps and a molded product obtained from the resin composition can be provided.

Below, it demonstrates in detail about the thermoplastic resin composition for vehicle lamps of this invention.
The present invention relates to a thermoplastic resin composition (graft copolymer (A) and copolymer (B) comprising 20 to 70 parts by weight of graft copolymer (A) and 30 to 80 parts by weight of copolymer (B). Is 100 parts by weight).

  The graft copolymer (A) used in the present invention comprises an aromatic vinyl monomer, cyanide in the presence of a composite rubber composed of a conjugated diene rubber-like polymer and a crosslinked acrylate ester polymer. A graft copolymer obtained by graft polymerization of at least one monomer selected from vinyl monomers and other vinyl monomers copolymerizable therewith.

  Examples of the conjugated diene rubber-like polymer constituting the composite rubber used in the present invention include polybutadiene rubber, styrene-butadiene rubber (SBR), styrene-butadiene-styrene (SBS) block copolymer, and styrene- (ethylene-butadiene). -Styrene (SEBS) block copolymer, acrylonitrile-butadiene rubber (NBR), methyl methacrylate-butadiene rubber. In particular, polybutadiene rubber and styrene-butadiene rubber are preferable.

  Although there is no restriction | limiting in particular in the weight average particle diameter of the conjugated diene type rubber-like polymer which comprises a composite rubber, From a viewpoint of a physical-property balance, it is preferable that it is 0.1-1.0 micrometer, 0.2-0.5 micrometer. It is more preferable that The weight average particle diameter of the conjugated diene rubber-like polymer can be adjusted by a known method, but the purpose is to produce a conjugated diene rubber-like polymer having a relatively small particle diameter in advance and agglomerate it. It is also possible to use an agglomerated enlarged conjugated diene rubbery polymer having a weight average particle diameter of

  The crosslinked acrylate polymer constituting the composite rubber used in the present invention is an acrylate monomer having an alkyl group having 1 to 16 carbon atoms in the presence of a crosslinking agent, such as methyl acrylate or ethyl acrylate. , Butyl acrylate, 2-ethylhexyl acrylate, or the like, or, if necessary, other copolymerizable monomers such as styrene, acrylonitrile, methyl methacrylate, etc. The resulting polymer.

  Examples of the crosslinking agent used in the crosslinked acrylic acid ester polymer constituting the composite rubber include divinylbenzene, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, diallyl phthalate, dicyclopentadiene di (meth) acrylate, Trimethylolpropane tri (meth) acrylate, pentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, triallyl cyanurate, triallyl isocyanurate Etc.

  The composite rubber used in the present invention can be obtained by emulsion polymerization of a monomer (mixture) constituting a crosslinked acrylate ester polymer in the presence of a conjugated diene rubber polymer. That is, the composite rubber of the present invention has a core-shell structure in which the conjugated diene rubber-like polymer is the core and the crosslinked acrylate polymer is the shell.

  The ratio of the conjugated diene rubbery polymer and the crosslinked acrylate polymer constituting the composite rubber used in the present invention is 5 to 50% by weight of the conjugated diene rubbery polymer, and the crosslinked acrylate polymer. Although it is necessary to be 50 to 95% by weight, the conjugated diene rubbery polymer is preferably 7 to 40% by weight and more preferably 10 to 30% by weight from the viewpoint of balance of physical properties.

  The composite rubber used in the present invention is a conjugated diene rubber-like polymer core as described above, and is characterized by having a core-shell structure in which the cross-linked acrylate polymer is a shell. Not all acrylate-based polymers are polymerized into conjugated diene rubber-like polymers, and some may exist as single particles of crosslinked acrylate-based polymers. Thereafter, the conjugated diene rubber-like polymer and the cross-linked acrylic acid ester polymer include not only the composite rubber having a core-shell structure but also the cross-linked acrylic acid ester polymer present alone. Even so, it is called composite rubber.

  In the present invention, regarding the composite rubber present in the graft copolymer (A), the number of composite rubber particles having an equivalent circle particle diameter of 150 nm or less needs to be 50% or less of the total composite rubber particles. If the number of particles of the composite rubber having an equivalent circle particle size of 150 nm or less is more than 50%, the resulting thermoplastic resin composition is inferior in tapping strength and vapor deposition appearance. The number of particles having a circle-equivalent particle diameter of 150 nm or less is preferably 40% or less, and more preferably 20% or less.

  The composite rubber present in the graft copolymer (A) and having an equivalent circle particle diameter of 150 nm or less is often a single particle of the above-mentioned crosslinked acrylate polymer, and the single particle is thermoplastic. This is a main factor that adversely affects the tapping strength and vapor deposition appearance of the resin composition. Therefore, in order to reduce particles having an equivalent circle particle diameter of 150 nm or less, it is necessary to prevent the generation of single particles of a crosslinked acrylate ester polymer as much as possible during the production of the composite rubber.

  Further, even if the composite rubber having a core-shell structure is used, the present invention is a single particle of a crosslinked acrylate ester-based polymer because the tapping strength and the vapor deposition appearance are adversely affected if the equivalent circle particle diameter is 150 nm or less. It is necessary that the number of particles having a circle-equivalent particle diameter of 150 nm or less is 50% or less of the composite rubber containing.

  Any method may be used as a method of not producing single particles of the crosslinked acrylic ester polymer at the time of polymerization of the composite rubber used in the present invention. For example, a method of changing an emulsifier amount, a monomer addition rate, etc. It is done.

  When polymerizing the composite rubber, the polymerization initiator used is a water-soluble polymerization initiator such as potassium persulfate, sodium persulfate, ammonium persulfate, cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, acetyl Oil-soluble polymerization initiators such as peroxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide can be appropriately used. Furthermore, specific examples of the reducing agent preferably used include ferrous sulfate heptahydrate, sulfite, bisulfite, pyrosulfite, nitrite, nithionate, thiosulfate, formaldehyde sulfonate, Examples thereof include benzaldehyde sulfonate, carboxylic acids such as L-ascorbic acid, tartaric acid and citric acid, further reducing sugars such as lactose, dextrose and saccharose, and amines such as dimethylaniline and triethanolamine. Examples of the chelating agent include tetrasodium pyrophosphate and sodium ethylenediaminetetraacetate.

  As the emulsifier used when polymerizing the composite rubber, carboxylate, sulfate, sulfonate and the like can be used as appropriate. Furthermore, specific examples of emulsifiers preferably used include potassium oleate, dipotassium alkenyl succinate, sodium rosinate, sodium dodecylbenzenesulfonate, and the like.

  The gel content in the toluene solvent of the composite rubber used in the present invention is not particularly limited, but from the viewpoint of physical properties balance, the gel content of the composite rubber is preferably 90% or more, and 95% or more. It is more preferable.

  The graft copolymer (A) used in the present invention includes an aromatic vinyl monomer, a vinyl cyanide monomer, and other vinyls copolymerizable with these in the presence of the above composite rubber. It is a graft copolymer obtained by graft polymerization of at least one monomer selected from the system monomers.

  The graft copolymer (A) needs to contain 10 to 80 parts by weight of composite rubber in 100 parts by weight of the graft copolymer. If the composite rubber is less than 10 parts by weight, the impact resistance is poor, and if it exceeds 80 parts by weight, the fluidity is poor. The content of the composite rubber is preferably 30 to 70 parts by weight, and more preferably 40 to 60 parts by weight.

  Examples of the aromatic vinyl monomer constituting the graft copolymer (A) include styrene, α-methylstyrene, paramethylstyrene, bromostyrene, and the like, and one or more of them can be used. In particular, styrene and α-methylstyrene are preferable.

  Examples of the vinyl cyanide monomer constituting the graft copolymer (A) include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile and the like, and one or more of them can be used. Particularly preferred is acrylonitrile.

  Examples of other copolymerizable vinyl monomers constituting the graft copolymer (A) include (meth) acrylic acid ester monomers, maleimide monomers, amide monomers, and the like. 1 type, or 2 or more types can be used. (Meth) acrylic acid ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl acrylate, (meth) acrylic Examples include phenyl acid, 4-t-butylphenyl (meth) acrylate, (di) bromophenyl (meth) acrylic acid, chlorophenyl (meth) acrylate, and the maleimide monomer includes N-phenylmaleimide, N-cyclohexylmaleimide and the like can be exemplified, and examples of the amide monomer include acrylamide and methacrylamide.

  The composition ratio of the above-mentioned monomer graft-polymerized with the composite rubber is not particularly limited, but 60 to 90% by weight of aromatic vinyl monomer, 10 to 40% by weight of vinyl cyanide monomer, and copolymerizable Other vinyl monomer composition ratio of 0 to 30% by weight, aromatic vinyl monomer 30 to 80% by weight, (meth) acrylic acid ester monomer 20 to 70% by weight and copolymerizable Composition ratio of other vinyl monomers 0 to 50% by weight, aromatic vinyl monomers 20 to 70% by weight, (meth) acrylic acid ester monomers 20 to 70% by weight, vinyl cyanide monomer The composition ratio is preferably 10 to 60% by weight of the monomer and 0 to 30% by weight of another copolymerizable vinyl monomer.

  There is no restriction | limiting in particular in the method for superposing | polymerizing a graft copolymer (A), An emulsion polymerization method, suspension polymerization method, block polymerization method, etc. can be used. When the emulsion polymerization method is used, a latex of the graft copolymer (A) can be obtained by graft polymerization of the above-described monomer to the above-described composite rubber. The latex of the graft copolymer (A) is coagulated by a known method, and the powder of the graft copolymer (A) can be obtained through washing, dehydration, and drying steps.

  Graft rate of the graft copolymer (A) (determined from the acetone soluble and insoluble amounts of the graft copolymer and the weight of the composite rubber in the graft copolymer), and the reduced viscosity of the acetone soluble component (0. 4 g / 100 cc, measured at 30 ° C. as an N, N dimethylformamide solution), any structure can be used depending on the required performance, but from the viewpoint of balance of physical properties, the graft ratio is 5 to 150 %, And the reduced viscosity is preferably 0.2 to 2.0 dl / g.

  As the aromatic vinyl monomer, vinyl cyanide monomer, and other copolymerizable monomers constituting the copolymer (B), monomers used in the graft copolymer (A) The same can be used.

  The copolymer (B) used in the present invention can be polymerized by a conventionally known polymerization technique such as an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or a solution polymerization method. The polymers obtained by the respective polymerization methods may be combined, or one or two or more types of copolymers having different polymerization methods and composition ratios may be combined.

  Although there is no restriction | limiting in particular in the ratio of each monomer which comprises a copolymer (B), When a total amount of the monomer which comprises a copolymer (B) is 100 weight part, it is a viewpoint of a physical-property balance. From 50 to 85 parts by weight of the aromatic vinyl monomer, from 15 to 50 parts by weight of the vinyl cyanide monomer, and from 0 to 35 parts by weight of the other copolymerizable monomer.

  The thermoplastic resin composition for vehicle lamps of the present invention has a graft copolymer (A) of 20 to 70 parts by weight when the total of the graft copolymer (A) and the copolymer (B) is 100 parts by weight. It is necessary that the copolymer (B) has a ratio of 30 to 80 parts by weight. When the graft copolymer (A) is less than 20 parts by weight, the impact resistance is poor. If it exceeds 70 parts by weight, the fluidity and vapor deposition appearance are poor. From the viewpoint of the balance between physical properties such as impact resistance, fluidity and tapping strength and weather resistance, the graft polymer (A) is 30 to 60 parts by weight, and the copolymer (B) is 40 to 70 parts by weight. Is preferred. Further, the amount of the composite rubber contained in the thermoplastic resin composition for vehicle lamps is preferably 3 to 50% by weight, more preferably 10 to 30% by weight from the viewpoint of physical property balance.

  The thermoplastic resin composition for vehicle lamps according to the present invention includes hindered amine light stabilizers, hindered phenol-based, sulfur-containing organic compound-based, phosphorus-containing organic compound-based antioxidants, phenol-based, acrylate as necessary. Heat stabilizers such as benzoate, benzotriazole, benzophenone, salicylate UV absorbers, organic nickel, lubricants such as higher fatty acid amides, plasticizers such as phosphate esters, polybromophenyl ether, Tetrabromobisphenol-A, brominated epoxy oligomers, halogenated compounds such as brominated compounds, phosphorus compounds, flame retardants and flame retardants such as antimony trioxide, odor masking agents, carbon black, titanium oxide, pigments, and Dye etc. can also be added. Furthermore, reinforcing agents and fillers such as talc, calcium carbonate, aluminum hydroxide, glass fiber, glass flake, glass bead, carbon fiber, and metal fiber can be added.

  The thermoplastic resin composition for vehicle lamps of the present invention can be used by mixing with other thermoplastic resins as long as the purpose is not impaired. Examples of such other thermoplastic resins include polycarbonate resins such as polycarbonate, acrylic resins such as polymethyl methacrylate, polyamide resins such as nylon 6, nylon 66, nylon 11, and nylon 12, polybutylene terephthalate resin, Polyester resins such as polyethylene terephthalate resin and polylactic acid can be used.

  The thermoplastic resin composition for a vehicle lamp of the present invention can be obtained by mixing the above-described components. In order to mix, well-known kneading apparatuses, such as an extruder, a roll, a Banbury mixer, a kneader, can be used, for example.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” are based on weight.

Production of small particle size styrene-butadiene rubber latex After replacing the inside of a 10 liter pressure vessel with nitrogen, 95 parts by weight of 1,3-butadiene, 5 parts by weight of styrene, 0.5 parts by weight of n-dodecyl mercaptan, potassium persulfate 0.3 parts by weight, disproportionated sodium rosinate 1.8 parts by weight, sodium hydroxide 0.1 parts by weight, and deionized water 145 parts by weight were charged and reacted at 70 ° C. for 8 hours with stirring. Thereafter, 0.2 parts by weight of disproportionated sodium rosinate, 0.1 parts by weight of sodium hydroxide and 5 parts by weight of deionized water were added. Further, stirring was continued for 6 hours while maintaining the temperature at 70 ° C. to complete the reaction. Thereafter, the remaining 1,3-butadiene was removed under reduced pressure to obtain a styrene-butadiene rubber latex. The obtained styrene-butadiene rubber latex was dyed with osmium tetroxide (OsO ₄ ), dried, and photographed with a transmission electron microscope. Using an image analysis processor (apparatus name: IP-1000PC manufactured by Asahi Kasei Co., Ltd.), the area of 1000 rubber particles was measured, and the equivalent-circle particle diameter (diameter) was obtained. The weight average particle of styrene-butadiene rubber As a result of calculating the diameter, the weight average particle diameter was 120 nm.

Production of agglomerated styrene-butadiene rubber latex 270 parts by weight of the styrene-butadiene rubber latex obtained above and 0.1 part by weight of sodium dodecylbenzenesulfonate were added to a 10-liter pressure vessel and stirred for 10 minutes. Thereafter, 20 parts by weight of 5% aqueous phosphoric acid solution was added over 10 minutes. Subsequently, 10 parts by weight of a 10% aqueous potassium hydroxide solution was added to obtain an agglomerated styrene-butadiene rubber latex (1).
As a result of calculating the weight average particle diameter of the agglomerated styrene-butadiene rubber by the above-described method, the weight average particle diameter was 330 nm.

To a 10 liter pressure vessel, 270 parts by weight of the styrene-butadiene rubber latex obtained above and 0.3 parts by weight of sodium dodecylbenzenesulfonate were added and stirred and mixed for 10 minutes, and then 20 parts by weight of 5% aqueous phosphoric acid solution. Was added over 10 minutes. Next, 10 parts by weight of a 10% aqueous potassium hydroxide solution was added to obtain an agglomerated styrene-butadiene rubber latex (2).
As a result of calculating the weight average particle size of the agglomerated styrene-butadiene rubber by the above-mentioned method, the weight average particle size was 250 nm.

Production of cross-linked butyl acrylate rubber latex In a nitrogen-replaced glass reactor, 180 parts by weight of deionized water, 15 parts by weight of butyl acrylate, 0.1 parts by weight of allyl methacrylate, 0.16 parts by weight of dipotassium alkenyl succinate (in terms of solid content) ), 0.15 part by weight of potassium persulfate was added and reacted at 65 ° C. for 1 hour. Thereafter, an emulsifier aqueous solution in which 0.64 parts by weight of dipotassium alkenyl succinate (in terms of solid content) was dissolved in 85 parts by weight of butyl acrylate and 0.53 parts by weight of allyl methacrylate and 20 parts by weight of deionized water was added for 3 hours. Over time. After dripping, it was kept for 3 hours to obtain a crosslinked butyl acrylate rubber latex.

The weight average particle diameter of the obtained crosslinked butyl acrylate rubber latex was calculated by the method described below. Graft copolymerization was performed using 15 parts (solid content) of the obtained crosslinked butyl acrylate rubber latex, 64 parts of styrene, and 21 parts of acrylonitrile to obtain a graft copolymer. The graft copolymer powder was melt-kneaded to obtain pellets. From the obtained pellet, an ultrathin section was cut out at −85 ° C. using a cryomicrotome, stained with ruthenium tetroxide (RuO ₄ ), and photographed with a transmission electron microscope (JEM-1400: manufactured by JEOL Ltd.). I took a picture. Using an image analyzer (Asahi Kasei IP-1000PC), the area of 1000 cross-linked butyl acrylate rubber particles was measured, the equivalent circle diameter (diameter) was determined, and the weight average particle diameter of the cross-linked butyl acrylate rubber latex was calculated. As a result, the weight average particle size was 200 nm.

Manufacture of composite rubber latex (a-1) A 10 L glass reactor is charged with 20 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (1) and 160 parts by weight of deionized water, and nitrogen replacement is performed. went. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 20 parts by weight of butyl acrylate and 0.1 parts by weight of allyl methacrylate were added. An aqueous solution in which 0.9 part by weight of dipotassium alkenyl succinate and 0.1 part by weight of tertiary butyl hydroperoxide are dissolved in 25 parts by weight of deionized water after the temperature in the tank reaches 50 ° C. 60 parts by weight of butyl acrylate and 0.4 parts by weight of allyl methacrylate were continuously added dropwise over 5 hours. After dropping, the mixture was held for 3 hours to obtain a composite rubber latex (a-1) composed of an enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Manufacture of composite rubber latex (a-2) A 10 L glass reactor is charged with 30 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (1) and 160 parts by weight of deionized water. went. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 25 parts by weight of butyl acrylate and 0.2 parts by weight of allyl methacrylate were added. An aqueous solution in which 0.9 part by weight of dipotassium alkenyl succinate and 0.1 part by weight of tertiary butyl hydroperoxide are dissolved in 25 parts by weight of deionized water after the temperature in the tank reaches 50 ° C. 45 parts by weight of butyl acrylate and 0.24 parts by weight of allyl methacrylate were continuously added dropwise over 3 hours. After dropping, the mixture was held for 3 hours to obtain a composite rubber latex (a-2) composed of an enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Manufacture of composite rubber latex (a-3) A 10 L glass reactor is charged with 20 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (2) and 160 parts by weight of deionized water, and nitrogen replacement is performed. went. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 20 parts by weight of butyl acrylate and 0.1 parts by weight of allyl methacrylate were added. An aqueous solution in which 0.9 part by weight of dipotassium alkenyl succinate and 0.1 part by weight of tertiary butyl hydroperoxide are dissolved in 25 parts by weight of deionized water after the temperature in the tank reaches 50 ° C. 60 parts by weight of butyl acrylate and 0.4 parts by weight of allyl methacrylate were continuously added dropwise over 5 hours. After dripping, it hold | maintained for 3 hours and obtained composite rubber latex (a-3) comprised from enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Manufacture of composite rubber latex (a-4) Into a 10 L glass reactor, 20 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (1) and 160 parts by weight of deionized water were charged and replaced with nitrogen. It was. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 5% of an emulsifier solution prepared by dissolving 0.9 parts by weight of dipotassium alkenyl succinate and 0.1 parts by weight of tertiary butyl hydroperoxide in 25 parts by weight of deionized water, 16 parts by weight of butyl acrylate, 0% of allyl methacrylate .1 part by weight was added, and the temperature in the tank reached 50 ° C., and held for 1 hour. The remaining emulsifier solution, 64 parts by weight of butyl acrylate, and 0.4 parts by weight of allyl methacrylate were added over 5 hours. It was dripped continuously. After dropping, the mixture was held for 3 hours to obtain a composite rubber latex (a-4) composed of an enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Manufacture of composite rubber latex (a-5) A 10 L glass reactor was charged with 20 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (1) and 160 parts by weight of deionized water, followed by nitrogen substitution. It was. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 20% of an emulsifier solution obtained by dissolving 0.9 parts by weight of dipotassium alkenyl succinate and 0.1 parts by weight of tertiary butyl hydroperoxide in 25 parts by weight of deionized water, 16 parts by weight of butyl acrylate, 0% of allyl methacrylate .1 part by weight was added, and the temperature in the tank reached 50 ° C., and held for 1 hour. The remaining emulsifier solution, 64 parts by weight of butyl acrylate, and 0.4 parts by weight of allyl methacrylate were added over 5 hours. It was dripped continuously. After dropping, the mixture was held for 3 hours to obtain a composite rubber latex (a-5) composed of an enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Manufacture of composite rubber latex (a-6) A 10 L glass reactor was charged with 20 parts by weight (solid content) of the above-mentioned agglomerated styrene-butadiene rubber latex (1) and 160 parts by weight of deionized water, followed by nitrogen substitution. It was. After nitrogen substitution, when the temperature in the tank reached 45 ° C., 0.2 parts by weight of glucose, 0.03 part by weight of anhydrous sodium pyrophosphate and 0.001 part by weight of ferrous sulfate were added to 20 parts by weight of deionized water. Dissolved aqueous solution was added. Furthermore, 40% of an emulsifier solution obtained by dissolving 0.9 parts by weight of dipotassium alkenyl succinate and 0.1 parts by weight of tertiary butyl hydroperoxide in 25 parts by weight of deionized water, 16 parts by weight of butyl acrylate, 0% of allyl methacrylate .1 part by weight was added, and the temperature in the tank reached 50 ° C., and held for 1 hour. The remaining emulsifier solution, 64 parts by weight of butyl acrylate, and 0.4 parts by weight of allyl methacrylate were added over 5 hours. It was dripped continuously. After dropping, the mixture was held for 3 hours to obtain a composite rubber latex (a-6) composed of an enlarged styrene-butadiene rubber and a crosslinked butyl acrylate polymer.

Production of Graft Copolymer (A-1) Into a glass reactor, 60 parts by weight (solid content) of the composite rubber latex (a-1) was charged and nitrogen substitution was performed. After nitrogen substitution, when the temperature inside the tank reached 60 ° C., 0.2 part by weight of glucose, 0.1 part by weight of anhydrous sodium pyrophosphate and 0.005 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. An aqueous solution dissolved in was added. After reaching 65 ° C., a mixture of 12 parts by weight of acrylonitrile, 28 parts by weight of styrene, 0.1 part by weight of tertiary decyl mercaptan, 0.3 part by weight of cumene hydroperoxide and 20 parts by weight of deionized water was mixed with potassium oleate. An aqueous emulsifier solution in which 0 part by weight was dissolved was continuously added dropwise over 5 hours. After dropping, the mixture was held for 3 hours to obtain a graft copolymer latex (A-1). Thereafter, salting out, dehydration, and drying were performed to obtain a powder of the graft polymer (A-1).

Production of graft copolymers (A-2) to (A-6) Graft copolymers (A-2) except that the composite rubber latex (a-1) was changed to the composite rubbers (a-2) to (a-6). -1), and graft copolymer latexes (A-2) to (A-6) were obtained. Thereafter, salting out, dehydration and drying were performed to obtain powders of graft polymers (A-2) to (A-6).

Production of Graft Copolymer (A-7) In a glass reactor, 60 parts by weight of agglomerated and enlarged styrene-butadiene rubber latex (1) was charged in terms of solid content, and nitrogen substitution was performed. After nitrogen substitution, when the temperature inside the tank reached 60 ° C., 0.2 part by weight of glucose, 0.1 part by weight of anhydrous sodium pyrophosphate and 0.005 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. After adding the aqueous solution dissolved in the solution, the temperature was raised to 65 ° C. Thereafter, 12 parts by weight of acrylonitrile, 28 parts by weight of styrene, 0.1 part of tertiary decyl mercaptan, 0.3 part by weight of cumene hydroperoxide and 20 parts by weight of deionized water were added with 1.0 part by weight of potassium oleate. The dissolved aqueous emulsifier solution was continuously added dropwise over 4 hours. After dropping, the mixture was held for 3 hours to obtain a graft copolymer latex (A-7). Thereafter, salting-out, dehydration and drying were performed to obtain a graft polymer (A-7) powder.

Production of Graft Copolymer (A-8) A glass reactor was charged with 15 parts by weight of agglomerated and enlarged styrene-butadiene rubber latex (1) in terms of solid content and 45 parts by weight of crosslinked butyl acrylate rubber latex in terms of solid content. Nitrogen replacement was performed. After nitrogen substitution, when the temperature inside the tank reached 60 ° C., 0.2 part by weight of glucose, 0.1 part by weight of anhydrous sodium pyrophosphate and 0.005 part by weight of ferrous sulfate were added by 10 parts by weight of deionized water. After adding the aqueous solution dissolved in the solution, the temperature was raised to 65 ° C. Thereafter, 12 parts by weight of acrylonitrile, 28 parts by weight of styrene, 0.1 part of tertiary decyl mercaptan, 0.3 part by weight of cumene hydroperoxide and 20 parts by weight of deionized water were added with 1.0 part by weight of potassium oleate. The dissolved aqueous emulsifier solution was continuously added dropwise over 4 hours. After dropping, the mixture was held for 3 hours to obtain a graft copolymer latex (A-8). Thereafter, salting-out, dehydration and drying were performed to obtain a graft polymer (A-8) powder.

Production of copolymer (B) A copolymer (B) comprising 70 parts by weight of styrene and 30 parts by weight of acrylonitrile was obtained by a known bulk polymerization method. As a result of measuring the reduced viscosity of the obtained copolymer (B) by the above method, the reduced viscosity was 0.60 dl / g.

Additive (C)
Light stabilizer: ADEKA Corporation ADK STAB LA77Y
UV absorber: Sumitomo 200 manufactured by Sumitomo Chemical Co., Ltd.

<Examples 1-5 and Comparative Examples 1-6>
After the graft copolymer (A), copolymer (B) and additive (C) shown in Table 1 were mixed, pellets were obtained by melt-kneading at 240 ° C. using a 40 mm twin screw extruder. Various molded products were molded from the obtained pellets with an injection molding machine set at 250 ° C., and physical properties were evaluated. The evaluation results are shown in Table 1. In addition, each evaluation method is shown below.

The obtained pellet was cut out at a low temperature of −85 ° C. using a cryomicrotome to obtain an ultrathin section. The obtained ultrathin sections were stained with ruthenium tetroxide (RuO ₄ ), and observed and photographed using a transmission electron microscope (JEM-1400: manufactured by JEOL Ltd.). The area of 1000 particles was measured using an image analysis apparatus (Asahi Kasei IP-1000PC), and the equivalent circle diameter (diameter) was determined to calculate the ratio of the number of rubber particles that is 150 nm or less.

Impact Resistance Various test pieces were molded according to ISO test method 294 using the pellets obtained in each Example and Comparative Example, and impact resistance was measured.
The impact resistance was in conformity with ISO 179, and a Charpy impact value with a notch was measured at a thickness of 4 mm. Unit: kJ / m ²

The pellets obtained in Examples and Comparative Examples fluidity, in compliance with ISO 1133, 220 ° C., was measured melt volume flow rate under the condition of 10kg load. Unit; ^cm 3/10 minutes

For evaluation of weather resistance, the pellets obtained in each of Examples and Comparative Examples were used, and injection molding machine (SAV-30-30 manufactured by Yamashiro Seiki Seisakusho, cylinder temperature: 210 ° C, mold temperature: 50 ° C) was used. A molded product (90 mm × 55 mm × 2.5 mm) was used. Using a Sunshine Super Long Life Weather Meter, WEL-SUN-HCH-B, manufactured by Suga Test Instruments Co., Ltd., an accelerated exposure test was conducted for 500 hours under conditions of 63 ° C. and rain. Thereafter, the color difference (ΔE) before and after exposure was measured using a colorimeter.

Tapping strength Using the pellets obtained in each Example and Comparative Example, a molded product having a boss portion with an inner diameter of 3.2 mm, an outer diameter of 9.0 mm, and a height of 25 mm in the center (a disk shape with a diameter of 130 mm and a thickness of 3 mm) ) With an injection molding machine. Insert a JIS Class 2 M4 × 12 mm self-tapping screw and 1 mm thick washer into the boss part of this molded product in an environment of minus 10 ° C., and visually check for cracks in the boss part when tightened with a torque of 1.5 Nm. Confirmed by
○: No crack or crack occurred △: Slightly cracked ×: Significant crack or crack occurred

Vapor deposition appearance Using pellets obtained in each Example and Comparative Example, obtained by molding after being retained in the cylinder for 15 minutes with a plate obtained by molding with an injection molding machine set at 260 ° C. The prepared plates were prepared, and the surfaces of the plates were subjected to a vapor deposition treatment, and the change in the degree of fogging of the vapor deposition appearance between the unretained product and the 15-minute retained product was determined as follows.
○: Almost no change in the degree of fogging of the vapor deposition appearance in the non-staying and staying products ×: There is a clear change in the degree of clouding of the deposition appearance in the non-staying and staying products

  As shown in Table 1, Examples 1 to 5 are examples of the thermoplastic resin composition for vehicle lamps according to the present invention, and are necessary as a resin composition for vehicle lamps such as impact resistance, fluidity, and weather resistance. In addition to excellent performance balance, it has excellent vapor deposition appearance and tapping strength in a low temperature environment.

  As shown in Table 1, Comparative Example 1 was inferior in impact resistance and tapping strength because the amount of the graft copolymer used was small. In Comparative Example 2, since the amount of the graft copolymer used was large, the fluidity and the vapor deposition appearance were inferior. Comparative Examples 3 and 4 were inferior in impact resistance, tapping strength, and vapor deposition appearance because the number of composite rubber particles having a circle equivalent particle diameter of 150 nm or less exceeded 50%. In Comparative Example 5 using a conjugated diene rubber and Comparative Example 6 in which a conjugated diene rubber-like polymer and a cross-linked acrylate polymer are not present as a composite rubber, the weather resistance was poor.

  As described above, the resin composition for vehicle lamps of the present invention not only has excellent performance balance required as a resin composition for vehicle lamps such as impact resistance, fluidity, and weather resistance, but also has a vapor deposition appearance and a vehicle lamp product. Since it is excellent in tapping strength at the time of attachment, especially in a low temperature environment, the added value as a resin composition for vehicle lamps is high, and the utility value as a vehicle lamp product is high.

Claims (3)

A thermoplastic resin composition containing 20 to 70 parts by weight of the graft copolymer (A) and 30 to 80 parts by weight of the copolymer (B) (the total of the graft copolymer (A) and the copolymer (B) is 100). And the graft copolymer (A) is a composite rubber having a core-shell structure composed of 5 to 50% by weight of a conjugated diene rubbery polymer and 50 to 95% by weight of a crosslinked acrylate polymer. 10 to 80 parts by weight, a vinyl cyanide monomer, a monomer 20 to 90 parts by weight of at least one selected aromatic vinyl monomer or we obtained by graft-polymerizing, graft A graft copolymer characterized in that the number of particles of a composite rubber having an equivalent circle particle diameter of 150 nm or less with respect to the composite rubber present in the polymer is 20% or less of the total composite rubber particles, (B) is aromatic vinyl A vehicle lamp characterized by being a copolymer obtained by copolymerizing a monomer, a vinyl cyanide monomer, and, if necessary, other vinyl monomers that can be copolymerized Thermoplastic resin composition.   A lamp molded product obtained by molding the thermoplastic resin composition for a vehicle lamp according to claim 1. The vehicle lamp comprised with the lamp molded article of Claim 3.