Resin composition

Abstract

Provided is a resin composition that has excellent physical properties and is less likely to cause mold staining during molding. [Solution] According to one aspect of the present invention, there is provided a resin composition comprising an acrylonitrile-butadiene-styrene copolymer (ABS resin) and glycerin, wherein the content of glycerin in the resin composition is less than 100 ppm.

Description

[Technical Field]

[0001] The present invention relates to a resin composition. [Background technology]

[0002] Acrylonitrile-butadiene-styrene copolymer (ABS resin) is used in a wide range of applications due to its excellent impact resistance, moldability, etc. (see Patent Document 1). However, depending on storage conditions, external environment, etc., mold contamination may occur during molding of ABS resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-110943 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above circumstances, the present invention aims to provide a resin composition which is excellent in various physical properties and which is less likely to cause mold contamination during molding. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a resin composition comprising an acrylonitrile-butadiene-styrene copolymer (ABS resin) and glycerin, wherein the content of glycerin in the resin composition is less than 100 ppm.

[0006] According to this embodiment, it is possible to provide a resin composition that is excellent in various physical properties and is less likely to cause mold contamination during molding. DETAILED DESCRIPTION OF THE INVENTION

[0007] <Resin composition> The resin composition of this embodiment contains an acrylonitrile-butadiene-styrene copolymer (ABS resin). <<ABS resin>> ABS resin is a general term for resins obtained by copolymerization using acrylonitrile, butadiene, and styrene as raw material monomers, and the ratio of each component can be set arbitrarily. In addition to or instead of styrene, monomers such as α-methylstyrene, vinyltoluene, dimethylstyrene, chlorostyrene, vinylnaphthalene, etc. can be used as the raw material monomers. In addition to or instead of acrylonitrile, monomers such as methacrylonitrile, ethacrylonitrile, fumaronitrile, etc. can be used.

[0008] [[ID=??]] Furthermore, in addition to or instead of butadiene, monomers such as acrylic rubber mainly composed of butyl (meth)acrylate, chlorinated polyethylene, and ethylene-propylene-diene rubber (EPDM), which is an ethylene-based rubber, can be used. In addition to acrylonitrile, butadiene, and styrene, other monomers can be used as the raw material monomers. Examples of such other monomers include (meth)acrylate esters such as methyl methacrylate. Therefore, in this specification, the term "ABS resin" includes, in addition to acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-ethylene-propylene-diene-styrene copolymer (AES resin), acrylonitrile-styrene-acrylate copolymer (ASA resin), acrylonitrile-chlorinated polyethylene-styrene copolymer (ACS resin), methyl methacrylate-acrylonitrile-butadiene-styrene copolymer (MABS resin: transparent ABS resin), and the like.

[0009] As the ABS resin, any resin can be used as long as it is mainly composed of the ABS resin. For example, an ABS resin blend, an ABS resin alloy, etc. can be used. It should be noted that there seems to be a duplicate tag ID "13" in the original text. I have translated it as best as possible while keeping all the original content intact. If this is an error in the original, you may need to correct it accordingly.Examples of resins containing ABS resin as a main component include PC / ABS resin blends, which are blends of polycarbonate (PC) and ABS resin. Furthermore, for the purpose of improving the heat resistance of ABS resins and improving the compatibility of PC / ABS resin blends and polyamide / ABS resin blends, these may be blended with, for example, a styrene-N-phenylmaleimide-maleic anhydride copolymer.

[0010] The resin composition of this embodiment contains glycerin (glycerol) in addition to the ABS resin, and the content of glycerin in the resin composition is less than 100 ppm. In this specification, the content (mass % or ppm) of X in Y refers to the proportion of X when the total mass of Y is taken as 100 mass %. <<Glycerin>> As described above, mold contamination may occur during molding of ABS resin depending on storage conditions, external environmental conditions, etc. The present inventors conducted extensive research to solve this problem and found that the glycerin content in a resin composition containing an ABS resin has a significant effect. If the glycerin content in the resin composition is 100 ppm or more, mold contamination frequently occurs during molding of the resin composition, regardless of storage conditions, external environmental conditions, etc. Therefore, the glycerin content in the resin composition is adjusted to less than 100 ppm.

[0011] Here, glycerin is a component that is introduced into a resin composition along with a fatty acid or a salt thereof used as an emulsifier when an ABS resin is produced by emulsion polymerization, for example. From the viewpoint of preventing mold contamination during molding of the resin composition, it is preferable to minimize the glycerin content in the resin composition. To achieve this, it is effective to strongly heat the resin composition during the resin composition production process to volatilize the glycerin. However, in this case, the color of the resin composition may deteriorate due to the thermal history, and the mechanical strength of molded products obtained from the resin composition may decrease. For this reason, it is not realistic to reduce the glycerin content in the resin composition to 0 ppm, and it is preferable to leave a small amount of glycerin in the resin composition. Further investigations by the present inventors have revealed that, unexpectedly, by leaving a small amount of glycerin in the resin composition, the fluidity of the resin composition is improved, resulting in good molding processability.

[0012] For these reasons, the content of glycerin in the resin composition is preferably about 0.1 ppm or more and less than 100 ppm, more preferably about 0.1 ppm or more and 80 ppm or less, even more preferably about 0.5 ppm or more and 60 ppm or less, particularly preferably about 1 ppm or more and 40 ppm or less, and most preferably about 1.5 ppm or more and 20 ppm or less. A resin composition containing glycerin in the above range can improve moldability and suitably prevent mold staining during molding. The glycerin content in the resin composition can be adjusted by setting the production conditions in the production process of the ABS resin as described below, or by separately adding glycerin to the resin composition.

[0013] <Method of manufacturing resin composition> The resin composition of the present embodiment can be produced, for example, as follows. That is, first, a latex of a rubber-like polymer is obtained by emulsion polymerization. Next, to this latex, monomers such as a vinyl cyanide monomer and an aromatic vinyl monomer are added all at once, batchwise or continuously to carry out emulsion graft polymerization with the rubber-like polymer, thereby obtaining a latex of graft copolymer (A). Next, the graft copolymer (A) is precipitated (salted out) from this latex and recovered. Thereafter, the graft copolymer (A) is mixed with a copolymer (B) of monomers such as a vinyl cyanide monomer and an aromatic vinyl monomer.

[0014] <<Graft copolymer (A)>> Examples of the rubbery polymer contained in the graft copolymer (A) include polymers of conjugated diene monomers such as butadiene, isoprene, dimethylbutadiene, chloroprene, and cyclopentadiene; polymers of non-conjugated diene monomers such as 2,5-norbornadiene, 4-ethylidenenorbornene, and 1,4-cyclohexadiene; and, if necessary, copolymers exhibiting rubbery elasticity obtained by copolymerizing aromatic vinyl monomers such as styrene, α-methylstyrene, and vinyltoluene; cyanide vinyl monomers such as acrylonitrile and methacrylonitrile; acrylic acid ester monomers such as methyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate; methacrylic acid ester monomers such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; and olefin monomers such as ethylene, propylene, 1-butene, isobutylene, and 2-butene. In one embodiment, the rubbery polymer is preferably polybutadiene.

[0015] By using emulsion polymerization to prepare the rubbery polymer, the particle size, particle size distribution, etc. can be strictly controlled. In this emulsion polymerization, various surfactants such as anionic surfactants, nonionic surfactants, and amphoteric surfactants can be used as emulsifiers, and also fatty acids or salts thereof (preferably higher fatty acids or salts thereof) can be used. That is, the resulting resin composition may further contain fatty acids or salts thereof. Anionic surfactants include carboxylic acid compounds, sulfate ester compounds, and the like, and specific examples thereof include alkali metal salts of rosin acid, alkyl sulfonates having 8 to 20 carbon atoms, alkylaryl sulfates, and condensates of sodium naphthalenesulfonate and formaldehyde.

[0016] Specific examples of nonionic surfactants include polyvinyl alcohol or copolymers thereof (e.g., copolymers with acrylamide), polyvinyl ether or copolymers thereof (e.g., copolymers with maleic acid), polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, and polyoxyethylene fatty acid esters. Specific examples of amphoteric surfactants include lauryl dimethylaminoacetic acid betaine, lauric acid amidopropyl betaine, hydroxyalkyl (having 12 to 14 carbon atoms) hydroxyethyl sarcosine, lauric acid amidopropyl hydroxysulfobetaine, sodium cocoamphodiacetate, sodium lauraminopropionate, lauryl dimethylamine oxide, and N-[3-alkyl(12,14)oxy-2-hydroxypropyl]-L-arginine hydrochloride.

[0017] Examples of fatty acids (higher fatty acids) or salts thereof include a first higher fatty acid or salt thereof having 12 to 14 carbon atoms, a second higher fatty acid or salt thereof having 16 to 18 carbon atoms, or a mixture thereof. That is, the fatty acid or salt thereof preferably contains at least one of a first higher fatty acid or salt thereof having 12 to 14 carbon atoms, and a second higher fatty acid or salt thereof having 16 to 18 carbon atoms. The first higher fatty acid or a salt thereof is thought to be a component that affects, for example, the fluidity (melt mass flow rate: MFR) and heat resistance (weight loss temperature) of the resulting resin composition. The first higher fatty acid may be either a saturated fatty acid or an unsaturated fatty acid, but a saturated fatty acid is preferred. Examples of salts of the first higher fatty acid include alkali metal salts, ammonium salts, and lower amine salts. Among these, alkali metal salts are preferred as salts of the first higher fatty acid, and sodium salts or potassium salts are more preferred. The first higher fatty acid or its salt may be either an anhydride or a hydrate. The first higher fatty acid or its salt is preferably at least one selected from lauric acid (dodecanoic acid), tridecanoic acid, myristic acid (tetradecanoic acid), and salts thereof, and more preferably at least one selected from lauric acid, myristic acid, and salts thereof.

[0018] The content of the first higher fatty acid or its salt in the resin composition is preferably less than about 5000 ppm (about 10 ppm to less than 5000 ppm), more preferably about 50 ppm to 4000 ppm, even more preferably about 100 ppm to 3000 ppm, particularly preferably about 300 ppm to 2000 ppm, and most preferably about 500 ppm to 1000 ppm. In this case, the fluidity and heat resistance of the resin composition are easily improved. Hereinafter, in this specification, when the higher fatty acid is a salt or a hydrate, the content of the higher fatty acid or its salt is expressed as a value converted into the higher fatty acid which is a free acid. In this specification, the content of each higher fatty acid or salt thereof means the proportion of each higher fatty acid or salt thereof in the entire resin composition, unless otherwise specified.

[0019] The second higher fatty acid or a salt thereof is thought to be a component that affects, for example, the fluidity and molding processability (mold fouling resistance) of the resulting resin composition. The second higher fatty acid may be either a saturated fatty acid or an unsaturated fatty acid. Examples of salts of the second higher fatty acid include alkali metal salts, ammonium salts, and lower amine salts. Among these, alkali metal salts are preferred as salts of the second higher fatty acid, and sodium salts or potassium salts are more preferred. The second higher fatty acid or its salt may be either an anhydride or a hydrate. The second higher fatty acid or its salt is preferably at least one selected from palmitic acid, stearic acid, palmitoleic acid (hexadecenoic acid), oleic acid (octadecenoic acid), linoleic acid, linolenic acid, and salts thereof, and more preferably at least one selected from palmitic acid, stearic acid, oleic acid, linoleic acid, and salts thereof.

[0020] The content of the second higher fatty acid or its salt is preferably less than about 12,000 ppm, more preferably about 500 ppm to 10,000 ppm, even more preferably about 1,000 ppm to 8,000 ppm, particularly preferably about 1,500 ppm to 6,000 ppm, and most preferably about 2,000 ppm to 4,000 ppm, which is likely to improve the flowability and moldability of the resin composition. The second higher fatty acid or its salt preferably contains linoleic acid or its salt, which can further improve the molding processability of the resin composition. Also, 1 The higher fatty acid or its salt preferably includes myristic acid or its salt. Myristic acid By including the hydroxybenzoate or its salt, the heat resistance of the resin composition can be further improved. do.

[0021] The first higher fatty acid or its salt and the second higher fatty acid or its salt may contain an animal-derived higher fatty acid or its salt, but preferably contain a plant-derived higher fatty acid or its salt. By using a plant-derived higher fatty acid or its salt, carbon dioxide emissions can be reduced, thereby reducing the environmental load. Whether or not the first higher fatty acid or its salt and the second higher fatty acid or its salt contain a plant-derived higher fatty acid or its salt, and / or the content thereof, is specified in ASTM D6866. 14 It can be determined by measuring the biomass degree using C isotope measurement.

[0022] Furthermore, the plant-derived higher fatty acid or salt thereof preferably comprises a higher fatty acid or salt thereof prepared from at least one type of vegetable oil such as palm oil, palm olein, palm kernel oil, olive oil, rapeseed oil, sesame oil, cottonseed oil, soybean oil, sunflower oil, safflower oil, rice bran oil, corn oil, coconut oil, or linseed oil, and more preferably comprises a higher fatty acid or salt thereof prepared from at least one type of vegetable oil such as palm oil, palm olein, or palm kernel oil. Specifically, plant-derived higher fatty acids or salts thereof can be obtained by appropriately mixing higher fatty acids or salts thereof prepared from two or more types of vegetable oils, or by adding a desired higher fatty acid or salt thereof to a higher fatty acid or salt thereof prepared from at least one type of vegetable oil. By using such a first higher fatty acid or a salt thereof and a second higher fatty acid or a salt thereof, the type and content of the higher fatty acid or a salt thereof contained in the resin composition can be easily adjusted to within the desired range.

[0023] The volume average particle size of the rubbery polymer is preferably about 250 nm to 400 nm, more preferably about 300 nm to 500 nm. A mixture of rubbery polymers with different average particle sizes may also be used. Such rubbery polymers can be produced by first obtaining a rubbery polymer having a small particle size (e.g., a volume average particle size of 100 nm or less) by emulsion polymerization and then enlarging the small particle size rubbery polymer. Examples of enlarging methods include a method in which small particle size rubbery polymers are coagulated and enlarged by applying shear force using a Manton-Gaulin homogenizer or the like, or a method in which an acidic substance such as an inorganic acid, an organic acid, or an acid group-containing copolymer is added to a latex to chemically enlarge the rubbery polymer. Rubbery polymers produced by such methods are characterized by a broad particle size distribution.

[0024] Alternatively, rubbery polymers can be produced by emulsion polymerization using a small amount of emulsifier under conditions that reduce the particle number, resulting in enlargement. Rubbery polymers produced by this method are characterized by a narrow particle size distribution. The particle size of the rubber polymer can be measured by diluting the rubber polymer latex with pure water and using a laser diffraction scattering particle size distribution analyzer (Model LS230, manufactured by COULTER). The particle size distribution of the graft copolymer (A) can be measured by stirring 1 g of the graft copolymer (A) in 100 g of dimethylformamide (DMF) for 24 hours, diluting the mixture with more DMF to an appropriate concentration (the concentration that provides the highest sensitivity when measuring with a measuring instrument), and then using a laser diffraction / scattering particle size distribution measuring instrument.

[0025] Examples of the aromatic vinyl monomer used in the graft copolymer (A) include styrene, α-methylstyrene, chlorostyrene, butylstyrene, vinyltoluene, and divinylstyrene. On the other hand, examples of the vinyl cyanide monomer used in the graft copolymer (A) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Furthermore, examples of vinyl-based monomers that can be copolymerized with these and that are used as needed in the graft copolymer (A) include (meth)acrylic acid ester monomers such as methyl (meth)acrylate and butyl (meth)acrylate, and maleimide-based monomers such as n-methylmaleimide and n-phenylmaleimide. In one embodiment, the graft copolymer (A) is preferably an acrylonitrile-butadiene-styrene copolymer (ABS resin).

[0026] The graft copolymer (A) is preferably obtained by emulsion graft polymerization of 30 to 90 parts by mass of a mixture of monomers in the presence of 10 to 70 parts by mass of the rubbery polymer. By adjusting the amount of the rubbery polymer to fall within the above range, the appearance of the molded article can be improved, and the impact resistance and productivity of the resin composition can be improved. The monomer mixture preferably contains 10% by mass or more and 40% by mass or less of a vinyl cyanide monomer, 60% by mass or more and 90% by mass or less of an aromatic vinyl monomer, and 0% by mass or more and 30% by mass or less of a monomer copolymerizable therewith. During emulsion graft polymerization, it is preferred to add, to the rubber polymer latex, a mixture of monomers as well as, for example, a polymerization initiator, an emulsifier, a chain transfer agent, and the like.

[0027] As the polymerization initiator, for example, at least one of organic hydroperoxides such as cumene hydroperoxide and diisopropylbenzene hydroperoxide, organic peroxyesters such as t-butyl peroxyacetate, t-hexyl peroxybenzoate and t-butyl peroxybenzoate, persulfates such as potassium persulfate and ammonium persulfate, and diazo compounds such as azobisbutyronitrile can be used. In addition to these polymerization initiators, a reducing agent such as iron ions, a secondary reducing agent such as sodium formaldehyde sulfoxylate, and a chelating agent such as tetrasodium ethylenediaminetetraacetate can also be combined.

[0028] As the emulsifier, various surfactants such as anionic surfactants, nonionic surfactants, and amphoteric surfactants can be used, but it is preferable to use the first higher fatty acid or a salt thereof, the second higher fatty acid or a salt thereof, or a mixture thereof, as described above. In the latter case, the content of the first higher fatty acid or its salt in the mixture is preferably about 5% to 40% by mass, more preferably about 10% to 35% by mass, and even more preferably about 15% to 30% by mass, while the content of the second higher fatty acid or its salt in the mixture is preferably about 60% to 95% by mass, more preferably about 65% to 90% by mass, and even more preferably about 70% to 85% by mass.

[0029] Examples of chain transfer agents that can be used include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, and terpinolene. In this embodiment, a sulfur-containing chain transfer agent such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, or ethyl thioglycolate is preferably used as the chain transfer agent. Use of a sulfur-containing chain transfer agent makes it easy to adjust the balance of various physical properties of the resulting resin composition.

[0030] The amount of emulsifier used in emulsion graft polymerization is preferably about 0.1 to 10 parts by mass, more preferably about 0.5 to 7.5 parts by mass, and even more preferably about 1 to 5 parts by mass, per 100 parts by mass of the rubber-like polymer. The precipitating agent used for precipitating (salting out) the graft copolymer (A) may be, for example, at least one selected from the group consisting of sulfuric acid, acetic acid, magnesium sulfate, hydrochloric acid, and calcium chloride. The temperature in the emulsion graft polymerization is not particularly limited, but is preferably about 30°C or higher and 90°C or lower, more preferably about 40°C or higher and 80°C or lower, and even more preferably about 50°C or higher and 70°C or lower.

[0031] The graft copolymer (A) can be recovered by, for example, (i) dehydrating the slurry (latex after adding the precipitating agent) using a centrifugal dehydrator or a press dehydrator, and then drying using a flash dryer or the like, or (ii) simultaneously dehydrating and drying using a compression dehydrator or an extruder or the like. The bulk density of the graft copolymer (A) was measured by placing a thoroughly dried graft copolymer (A) in a cylindrical container with a volume of 100 cm 3 In this specification, the bulk density is measured in accordance with JIS K 6721:1977.

[0032] The content of the rubbery polymer in the graft copolymer (A) is preferably about 40% by mass or more and about 70% by mass or less, and more preferably about 45% by mass or more and about 65% by mass or less. In this case, the impact resistance of the graft copolymer (A) can be improved. The content of the rubbery polymer in the graft copolymer (A) can be adjusted, for example, by changing the ratio of the aromatic vinyl monomer and the vinyl cyanide monomer used relative to the rubbery polymer during emulsion graft polymerization. The constituent units of the graft copolymer (A), excluding the rubber polymer, preferably contain aromatic vinyl monomer units in an amount of about 65% to 85% by mass and vinyl cyanide monomer units in an amount of about 15% to 35% by mass, which can further improve the impact resistance and chemical resistance of the graft copolymer (A).

[0033] The graft copolymer (A) is preferably in the form of particles. The graft copolymer (A) is a rubber-like polymer particle formed by graft copolymerization of an aromatic vinyl monomer, a vinyl cyanide monomer, or the like. It is a component that is insoluble in organic solvents such as methyl ethyl ketone (MEK) and toluene and can be separated by centrifugation. Such particles are also called gel components. The graft copolymer (A) may form an occlusion structure in which particulate aromatic vinyl-vinyl cyanide copolymer is encapsulated inside particles of the rubbery polymer. In the resin composition obtained by melt-blending the graft copolymer (A) and the copolymer (B), the gel fraction exists as a dispersed phase in the form of particles in the continuous phase of the copolymer (B).

[0034] The volume average particle size of the graft copolymer (A), i.e., the volume average particle size of the gel fraction, is preferably about 0.1 μm or more and 1 μm or less, more preferably about 0.15 μm or more and 0.5 μm or less, which increases the impact resistance of the graft copolymer (A) and tends to improve the appearance of molded articles. In this specification, the volume-average particle size is a value calculated from an image analysis of particles dispersed in a continuous phase after ultrathin sections are cut from pellets of a resin composition obtained by melt-blending graft copolymer (A) and copolymer (B) and observing the pellets with a transmission electron microscope (TEM). The volume-average particle size can be adjusted, for example, by the particle size of the rubbery polymer used in emulsion graft polymerization. The particle size of the rubbery polymer can also be adjusted by the method of adding an emulsifier or the amount of water used during emulsion polymerization.

[0035] The graft ratio of the graft copolymer (A) is preferably about 10% by mass or more and 100% by mass or less, and more preferably about 20% by mass or more and 70% by mass or less. In this case, the impact resistance of the graft copolymer (A) can be further improved. In this specification, the graft ratio is a value calculated based on the gel fraction (G) and the rubber polymer content (RC) of the graft copolymer (A) by the formula: graft ratio (% by mass) = [(G-RC) / RC] × 100. The graft ratio represents the amount of aromatic vinyl-vinyl cyanide copolymer bound to rubbery polymer particles by grafts and the amount of aromatic vinyl-vinyl cyanide copolymer encapsulated in the particles per unit mass of the rubbery polymer. The graft ratio can be adjusted, for example, during emulsion graft polymerization, by setting the ratio of monomer to rubbery polymer, the type and amount of polymerization initiator, the amount of chain transfer agent, the amount of emulsifier, polymerization temperature, charging method (lump sum / multistage / continuous), monomer addition rate, etc.

[0036] The degree of swelling of the graft copolymer (A) in toluene is preferably about 5 to 20 times. This further improves the impact resistance of the graft copolymer (A) and tends to improve the appearance of molded articles. In this specification, the degree of swelling in toluene represents the degree of crosslinking of rubbery polymer particles, and is a value calculated by dissolving the graft copolymer (A) in toluene, separating the insoluble matter by centrifugation or filtration, and then calculating the ratio of the mass of the graft copolymer (A) in a state swollen with toluene to the mass of the dried graft copolymer (A) after removing the toluene by vacuum drying. The degree of swelling in toluene is affected by, for example, the degree of crosslinking of the rubber-like polymer used in emulsion graft polymerization, and this can be adjusted by selecting a polymerization initiator and / or an emulsifier during emulsion polymerization of the rubber-like polymer, setting the polymerization temperature, adding a polyfunctional monomer such as divinylbenzene, or the like.

[0037] <<Copolymer (B)>> The copolymer (B) is a copolymer comprising an aromatic vinyl monomer, a vinyl cyanide monomer, and, if necessary, a vinyl monomer copolymerizable therewith. Examples of the aromatic vinyl monomer used in the copolymer (B) include styrene, α-methylstyrene, and vinyltoluene. On the other hand, examples of the vinyl cyanide monomer used in the copolymer (B) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Furthermore, examples of vinyl-based monomers that can be copolymerized with these and that are used as needed in the copolymer (B) include (meth)acrylic acid ester monomers such as methyl (meth)acrylate and butyl (meth)acrylate, and maleimide-based monomers such as n-methylmaleimide and n-phenylmaleimide. In one embodiment, the copolymer (B) is preferably an acrylonitrile-styrene copolymer (AS resin or SAN resin).

[0038] The copolymer (B) preferably contains 10% by mass or more and 40% by mass or less of a vinyl cyanide monomer, 60% by mass or more and 90% by mass or less of an aromatic vinyl monomer, and 0% by mass or more and 30% by mass or less of a vinyl monomer copolymerizable therewith. By setting the content of the vinyl cyanide monomer within the above range, the moldability of the resin composition is improved, and the chemical resistance, impact resistance, and heat resistance can be improved. Furthermore, by setting the content of the aromatic vinyl monomer within the above range, the moldability of the resin composition is improved, and the impact resistance and chemical resistance can be improved. Furthermore, by setting the content of the copolymerizable vinyl monomer within the above range, the balance of moldability, impact resistance, heat resistance, etc. of the resin composition can be improved.

[0039] The resin composition preferably comprises 10 to 50 parts by mass of graft copolymer (A) and 50 to 90 parts by mass of copolymer (B), and the rubber polymer content in the resin composition is 3 to 35% by mass.More preferably, the resin composition comprises 15 to 45 parts by mass of graft copolymer (A) and 55 to 85 parts by mass of copolymer (B), and the rubber polymer content in the resin composition is 5 to 30% by mass. By setting the content of the graft copolymer (A) and the content of the rubber-like polymer in the resin composition within the above ranges, the impact strength of the resin composition can be improved, and the moldability and rigidity can be enhanced, resulting in a molded product with a good appearance.

[0040] The resin composition is preferably used in the form of pellets obtained by melt-kneading the graft copolymer (A) and the copolymer (B) in an extruder or the like. Suitable extruders include, for example, twin-screw extruders, single-screw extruders, multi-screw extruders, and continuous kneaders equipped with twin rotors. A combination of these extruders can also be used. The extruder has, for example, a kneading section for melt-kneading the graft copolymer (A) and the copolymer (B), and at least one devolatilizing section. The graft copolymer (A) and the copolymer (B) fed to the extruder are first melted in the kneading section and kneaded to a uniform composition. The kneading section is configured by combining mixing elements such as kneading disks. From the viewpoint of kneading efficiency, it is preferable to use an element downstream of the kneading section that has the effect of pushing the molten resin back upstream to fill the kneading section. Examples of such elements include a reverse lead full flight, a reverse offset kneading element, and a seal ring.

[0041] The resin composition melt-kneaded in the kneading section is conveyed in a molten state to a devolatilizing section, where volatile components are devolatilized through a vacuum vent. The devolatilized molten resin composition is extruded in the form of strands through a multi-hole die and cut by a cold cut method, an in-air hot cut method, an underwater hot cut method, or the like to obtain a resin composition in the form of pellets. As a method of devolatilization extrusion, a water injection devolatilization method in which water is added before the devolatilization section is preferred because it has excellent devolatilization efficiency. For example, a method in which the graft copolymer (A) and the copolymer (B) are melt-kneaded in a kneading section, and then a further kneading section is provided to uniformly knead and disperse water in the molten resin composition, and volatile components are devolatilized together with water in a downstream devolatilization section can be mentioned. Similarly, it is preferable that the kneading section where water is added and kneaded is also filled up. The amount of water added is preferably about 0.05% by mass or more and 2% by mass or less based on the resin composition.

[0042] The cylinder temperatures of the kneading section and the devolatilizing section of the extruder are not particularly limited, but are preferably about 150° C. or higher and 280° C. or lower, more preferably about 170° C. or higher and 260° C. or lower, and even more preferably about 190° C. or higher and 240° C. Setting the cylinder temperature high makes it easier to increase the efficiency of devolatilizing volatile components from the resin composition. The pressure in the devolatilization section is preferably set to about 10 mmHg or less when no water is added, and to about 40 mmHg or less when water is added. Here, the volatile components include monomers derived from the graft copolymer (A) and the copolymer (B), substances derived from the solvent components, substances derived from the monomer components produced by thermal decomposition, surfactants added as emulsifiers, substances derived from fatty acids (higher fatty acids) or salts thereof, impurities mixed in the emulsifiers (e.g., glycerin), etc.

[0043] During kneading, additives such as lubricants, pigments, dyes, antioxidants and ultraviolet absorbers, and reinforcing agents such as glass fibers and talc may be added to the resin composition as needed. In this embodiment, silicone oil is preferably used as the lubricant. By using silicone oil, it is easy to adjust the balance of various physical properties of the resulting resin composition. In the above-described method for producing a resin composition, the content of glycerin in the resin composition can be adjusted by, for example, changing at least one of the conditions in the precipitation step of the graft copolymer (A), the conditions in the extrusion step of the resin composition, and the addition of additional glycerin. In particular, when the graft copolymer (A) is produced by emulsion polymerization, if a fatty acid or a salt thereof is used as an emulsifier, glycerin produced when preparing the fatty acid or a salt thereof from fats and oils can be used as the glycerin contained in the resin composition without extensive removal.

[0044] <Characteristics of resin composition> The resin composition preferably has a melt mass-flow rate (MFR) of about 5 g / 10 min or more, more preferably about 10 g / 10 min or more, and even more preferably about 15 g / 10 min or more, as measured in accordance with JIS K 7210:1999 (ISO 1133:1997) at a temperature of 220°C and a load of 10 kg. The upper limit of the MFR of the resin composition is usually 30 g / 10 min. The MFR of the resin composition can be, for example, about 5 g / 10 min or more and 30 g / 10 min or less. A resin composition having such a melt mass-flow rate can be evaluated as having excellent fluidity and good moldability.

[0045] The resin composition preferably has a flexural strength of about 62 MPa or more, more preferably about 72 MPa or more, and even more preferably about 82 MPa or more, measured at 2 mm / min in accordance with JIS K 7171:2016 (ISO 178:2010). The upper limit of the flexural strength of the resin composition is usually about 100 MPa. The flexural strength of the resin composition can be, for example, about 62 MPa or more and 100 MPa or less. A molded article obtained from a resin composition having such a flexural strength can be determined to have excellent mechanical strength.

[0046] The resin composition has a Charpy impact strength of 8 kJ / m when measured at 23°C using a notched test piece in accordance with JIS K 7111-1:2012. 2 It is preferable that the concentration is about 13 kJ / m or more. 2 More than 35kJ / m 2 It is more preferable that the concentration is about 18kJ / m or less. 2 More than 30kJ / m 2 It is more preferable that the Charpy impact strength is about 100% or less. A molded article obtained from a resin composition having such a Charpy impact strength can be evaluated as having high toughness.

[0047] Furthermore, the resin composition preferably has a gloss of about 92% or more, more preferably about 94% or more, and even more preferably about 96% or more, or even 100%, measured at a measurement angle of 60° in accordance with JIS Z 8741: 1997. Molded articles obtained from such resin compositions can be evaluated as having extremely high gloss. The resin composition preferably has a deflection temperature under load measured flatwise at 1.8 MPa in accordance with JIS K 7191-1, -2:2015 of about 75° C. or higher, more preferably about 77.5° C. or higher and 95° C. or lower, and even more preferably about 80° C. or higher and 90° C. or lower. Molded articles obtained from such resin compositions can be evaluated as having extremely high mechanical strength.

[0048] Furthermore, the yellowness index (YI) of a 2 mm thick sample prepared using the resin composition, measured in accordance with JIS K 7373:2006, is preferably about 50 or less, more preferably about 35 to 47.5, even more preferably about 36 to 45, and particularly preferably about 37 to 42.5. Molded articles obtained from such resin compositions can be evaluated as having good hue. Furthermore, it may be provided in the following aspects.

[0049] (1) A resin composition comprising an acrylonitrile-butadiene-styrene copolymer (ABS resin) and glycerin, wherein the content of the glycerin in the resin composition is less than 100 ppm.

[0050] (2) The resin composition according to (1) above, wherein the content of the glycerin in the resin composition is 0.1 ppm or more and less than 100 ppm.

[0051] (3) The resin composition according to (1) or (2) above, further comprising a fatty acid or a salt thereof.

[0052] (4) In the resin composition described in (3) above, the fatty acid or its salt includes at least one of a first higher fatty acid or its salt having 12 to 14 carbon atoms, and a second higher fatty acid or its salt having 16 to 18 carbon atoms.

[0053] (5) The resin composition according to (4) above, wherein the second higher fatty acid or its salt includes at least one of linoleic acid or its salt and myristic acid or its salt.

[0054] (6) The resin composition according to any one of (1) to (5) above, wherein the melt mass-flow rate (MFR) measured in accordance with JIS K 7210:1999 at a temperature of 220°C and a load of 10 kg is 5 g / 10 min or more.

[0055] (7) In the resin composition according to any one of (1) to (6), the Charpy impact strength measured at 23°C using a notched test piece in accordance with JIS K 7111-1:2012 is 8 kJ / m 2 The above is the resin composition.

[0056] (8) The resin composition according to any one of (1) to (7) above, wherein the deflection temperature under load measured in a flatwise state at 1.8 MPa in accordance with JIS K 7191-1, -2:2015 is 75°C or higher. Of course, this is not the case.

[0057] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims. [Example]

[0058] The resin composition will be described in more detail below based on examples, but is not limited to these examples. 1. Production of polybutadiene (rubber-like polymer) First, 153 parts by mass of ion-exchanged water was added to an autoclave, and while stirring, 15 parts by mass of an 18% by mass aqueous solution of plant-derived potassium higher fatty acid (emulsifier), 0.08 parts by mass of divinylbenzene (crosslinking agent), 0.2 parts by mass of t-dodecyl mercaptan (chain transfer agent), 0.1 parts by mass of potassium persulfate (polymerization initiator), 0.3 parts by mass of potassium chloride, and 0.001 parts by mass of tetrasodium ethylenediaminetetraacetate tetrahydrate (chelating agent) were added and dissolved.

[0059] After that, 100 parts by mass of butadiene was added, and the temperature was raised to 62°C, and polymerization was carried out for 8 hours. Then, the temperature was raised to 70°C, and polymerization was carried out for an additional 7 hours. After the polymerization was completed, the pressure was released to remove the remaining butadiene, and a latex of polybutadiene with small particle sizes was obtained. This polybutadiene latex was agglomerated using a Manton-Gaulin homogenizer (pressure agglomeration agglomeration machine) to obtain a polybutadiene latex. The obtained polybutadiene latex had a solid content of 38% by mass and a volume average particle size of polybutadiene of 320 nm.

[0060] 2. Preparation of graft ABS resin (graft copolymer (A)) First, 100 parts by mass of polybutadiene latex was added to an autoclave, and then 5 parts by mass of acrylonitrile, 12 parts by mass of styrene, 0.1 part by mass of t-dodecyl mercaptan (chain transfer agent), and 48 parts by mass of ion-exchanged water were added while stirring, and the mixture was heated. After the temperature reached 50°C, 0.06 parts by mass of ferrous sulfate (reducing agent), 0.2 parts by mass of tetrasodium ethylenediaminetetraacetate tetrahydrate (chelating agent), and 4 parts by mass of sodium formaldehyde sulfoxylate dihydrate (secondary reducing agent: Rongalit dihydrate) were added to initiate polymerization. 40 minutes after the temperature reached 50°C, an additional 0.06 parts by mass of ferrous sulfate (reducing agent), 0.2 parts by mass of tetrasodium ethylenediaminetetraacetate tetrahydrate (chelating agent), and 4 parts by mass of sodium formaldehyde sulfoxylate dihydrate (secondary reducing agent: Rongalit dihydrate) were added.

[0061] Furthermore, a mixture of 0.1 parts by mass of diisopropylbenzene hydroperoxide (polymerization initiator: NOF Corporation's "Percumyl P"), 0.2 parts by mass of t-butyl peroxyacetate (polymerization initiator: Arkema Yoshitomi Co., Ltd.'s "Lupasol-70"), 3 parts by mass of an 18% by mass aqueous solution of plant-derived potassium higher fatty acid (emulsifier), 9 parts by mass of acrylonitrile, 21 parts by mass of styrene, 0.4 parts by mass of t-dodecyl mercaptan (chain transfer agent), and 13 parts by mass of ion-exchanged water was continuously added over 4 hours from the start of polymerization. After the addition was completed, the mixture was stirred at 70°C for 2 hours to complete the polymerization. This latex was added to a salt solution prepared by mixing 203 parts by mass of ion-exchanged water, 2.2 parts by mass of magnesium sulfate heptahydrate (precipitating agent), and 0.9 parts by mass of 20% by mass sulfuric acid (precipitating agent) for precipitation (salting out), to obtain a grafted ABS resin.

[0062] 3. Production of AS resin (copolymer (B)) The feed solution to be supplied to a 50 L reaction tank was prepared so as to contain 54 parts by mass of styrene, 20 parts by mass of acrylonitrile, 26 parts by mass of ethylbenzene, 0.02 parts by mass of t-butylperoxyisopropyl carbonate (polymerization initiator) as a polymerization initiator, and 0.06 parts by mass of n-dodecyl mercaptan (chain transfer agent) as a chain transfer agent. This feed liquid was bubbled with nitrogen gas, passed through a mixer, and then continuously fed to the reaction vessel at a rate of 10 L / hour into the liquid phase of the polymerization liquid. The polymerization temperature was maintained at 144°C, and the reaction liquid filling rate in the reaction vessel was maintained at 60 vol%, and the reaction liquid was continuously withdrawn in an amount equal to the amount of the feed liquid. The evaporated gas generated in the reaction vessel was condensed in a heat exchanger outside the reaction vessel, and the condensate was returned to the liquid phase in the reaction vessel. The extracted reaction liquid was introduced into a devolatilizer maintained at 250°C and a high vacuum of 11 mmHg, and the unreacted monomer and organic solvent were removed and recovered to obtain pelletized AS resin.

[0063] 4. Production of resin composition Example 1 A pellet-shaped resin composition was produced by blending 22 parts by mass of grafted ABS resin and 78 parts by mass of AS resin and melt-kneading them using a twin-screw extruder at a temperature of 225° C. In order to remove remaining volatile matter, devolatilization was performed through a vacuum vent and by pouring water into the mixture.

[0064] Example 2 A pellet-shaped resin composition was produced in the same manner as in Example 1, except that 250 ppm of glycerin was added to 100 parts by mass of the total of the graft ABS resin and AS resin. Example 3 A pellet-shaped resin composition was produced in the same manner as in Example 1, except that the brine used for precipitating (salting out) the grafted ABS resin was changed to brine prepared from 406 parts by mass of ion-exchanged water, 4.4 parts by mass of magnesium sulfate heptahydrate (precipitating agent), and 1.8 parts by mass of 20% by mass sulfuric acid (precipitating agent), and the temperature for melt-kneading the grafted ABS resin and AS resin was changed to 260°C.

[0065] Example 4 A pellet-shaped resin composition was produced in the same manner as in Example 1, except that 42 parts by mass of the graft ABS resin and 58 parts by mass of the AS resin were blended. (Comparative Example) A pellet-shaped resin composition was produced in the same manner as in Example 1, except that 500 ppm of glycerin was added to 100 parts by mass of the total of the graft ABS resin and AS resin.

[0066] 5. Measurement and Evaluation 5-1. Measurement of higher fatty acid content The content of higher fatty acids in each resin composition was measured using the following procedure. The freeze-pulverized resin composition was extracted with ethanol for 1.5 hours using an Exfat extraction device. The extract was then concentrated and filtered through a membrane filter to obtain a measurement sample. This was measured using a Shimadzu LC-10 CLASS-VP (detector: RID-10A, column: YMC ODS-A, mobile phase: MeOH: 1000 mL / H2O (0.5% H3PO4 / H2O): 80 mL).

[0067] 5-2. Measurement of glycerin content The glycerin content in each resin composition was measured by the following procedure. First, 5 mL of acetone was added to 0.5 g of the resin composition, and the mixture was left to stand for 12 hours, then shaken for 12 hours in a shaker to dissolve it. Next, 5 mL of methanol was added to cause reprecipitation, and the supernatant was filtered through a 0.45 μm membrane filter to prepare a measurement sample. Then, 1.0 μL of the measurement sample and 0.2 μL of a 10% by mass tetramethylammonium hydroxide / methanol solution were simultaneously injected into a JMS-Q1500GC manufactured by JEOL Ltd. (column: DB-WAX 0.25 mm, 0.50 μm, 30 m, column temperature: 70°C HOLD 5 min, heating rate 10°C / min, 200°C HOLD 12 min, split ratio 30:1, column flow rate 1 mL / min, measurement range: m / z = 29 to 550, quantification ion: m / z = 59 (reference ion m / z = 45, 89)) and measurements were performed.

[0068] 5-3.Melt mass-flow rate (MFR) measurement The melt mass flow rate (MFR) of the resin composition of each of the Examples and Comparative Examples was measured in accordance with JIS K 7210:1999 at a temperature of 220° C. and a load of 10 kg. 5-4. Charpy impact strength measurement The Charpy impact strength of the resin compositions of each of the Examples and Comparative Examples was measured at 23°C using notched test pieces in accordance with JIS K 7111-1:2012.

[0069] 5-5. Measurement of deflection temperature under load The deflection temperature under load of the resin compositions of each of the Examples and Comparative Examples was measured in accordance with JIS K 7191-1, -2:2015, flatwise, at 1.8 MPa. 5-6. Evaluation of mold fouling Mold fouling was evaluated by visually inspecting the degree of mold fouling caused by adhesion of low molecular weight components from the resin during injection molding of the resin compositions of each Example and Comparative Example according to the following criteria. A: No stains were observed even after 1,500 shots or more. B: Staining occurred after 1,000 or more shots but less than 1,500 shots. C: Staining occurred after less than 1000 shots.

[0070] 5-7. Yellowness Index (YI) Measurement The yellowness index (YI) of a 2 mm thick sample prepared using the resin composition of each of the Examples and Comparative Examples was measured in accordance with JIS K 7373:2006. The results are shown in Table 1 below. [Table 1]

[0071] From the results shown in Table 1, the resin compositions of each Example had an appropriate glycerin content, and therefore were superior in mold fouling resistance to the resin compositions of the Comparative Examples. It was also confirmed that the physical properties of the resin compositions of each Example could be controlled by adjusting the glycerin content.

Claims

1. A resin composition comprising: Contains acrylonitrile-butadiene-styrene copolymer (ABS resin) and glycerin, A resin composition, wherein the content of the glycerin in the resin composition is 0.1 ppm or more and less than 100 ppm.

2. The resin composition according to claim 1, The resin composition further contains a fatty acid or a salt thereof.

3. The resin composition according to claim 2, The resin composition, wherein the fatty acid or salt thereof comprises at least one of a first higher fatty acid or salt thereof having 12 to 14 carbon atoms, and a second higher fatty acid or salt thereof having 16 to 18 carbon atoms.

4. The resin composition according to claim 3, A resin composition, wherein the second higher fatty acid or its salt includes linoleic acid or its salt.

5. The resin composition according to claim 3, A resin composition, wherein the first higher fatty acid or a salt thereof includes myristic acid or a salt thereof.

6. The resin composition according to claim 1, A resin composition having a melt mass-flow rate (MFR) of 8 g / 10 min or more, measured in accordance with JIS K 7210:1999 at a temperature of 220°C and a load of 10 kg.

7. The resin composition according to claim 1, The Charpy impact strength measured at 23°C using a notched test piece in accordance with JIS K 7111-1:2012 is 8 kJ / m ２ The above is the resin composition.

8. The resin composition according to claim 1, A resin composition having a deflection temperature under load of 75°C or higher, measured flatwise at 1.8 MPa in accordance with JIS K 7191-1, -2:2015.

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