resin composition

Abstract

The present invention provides a resin composition containing ABS-based resin and possessing a good balance of various physical properties. [Solution] According to one aspect of the present invention, a resin composition is provided which contains an acrylonitrile-butadiene-styrene copolymer (ABS resin), silicon atoms (Si), and sulfur atoms (S), wherein the mass ratio of silicon atoms to sulfur atoms (Si / S) is less than 1.

Description

Technical Field

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

Background Art

[0002] Acrylonitrile-butadiene-styrene copolymer (ABS resin) is widely used in a wide range of applications because of its excellent impact resistance, moldability, etc. (see Patent Document 1). However, in general, in ABS resin, impact strength and other physical properties are in a trade-off relationship. Therefore, it is difficult to impart various physical properties to ABS resin in a well-balanced manner.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above circumstances, the present invention aims to provide a resin composition containing an ABS resin and having various physical properties in a good balance.

Means for Solving the Problems

[0005] According to one aspect of the present invention, there is provided a resin composition containing an acrylonitrile-butadiene-styrene copolymer (ABS resin), a silicon atom (Si), and a sulfur atom (S), and having a mass ratio of silicon atom to sulfur atom (Si / S) less than 1.

[0006] According to such an aspect, it is possible to provide a resin composition containing an ABS resin and having various physical properties in a good balance.

Modes for Carrying Out 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 arbitrarily set. In addition to or instead of styrene, monomers such as α-methylstyrene, vinyltoluene, dimethylstyrene, chlorostyrene, vinylnaphthalene, etc. can be used as raw material monomers. In addition to or instead of acrylonitrile, monomers such as methacrylonitrile, ethacrylonitrile, fumaronitrile, etc. can be used.

[0008] 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 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), etc.

[0009] As for the ABS resin, any resin can be used as long as it has ABS resin as its main component. For example, ABS resin blends and ABS resin alloys can be used. Examples of resins primarily composed of ABS resin include PC / ABS resin blends, which are made by blending polycarbonate (PC) and ABS resin. Furthermore, to improve the heat resistance of ABS resins and the compatibility of PC / ABS resin blends and polyamide / ABS resin blends, these may be blended with, for example, styrene-N-phenylmaleimide-maleic anhydride copolymer.

[0010] The inventors diligently studied how to improve the balance of various properties such as impact strength, melt mass flow rate (MFR), and flexural strength exhibited in resin compositions containing ABS resin. As a result, they found that the balance of various physical properties in a resin composition is easily influenced by the content of specific atoms in the resin composition, particularly the content of silicon atoms (Si) and sulfur atoms (S), with the sulfur atom (S) content having a particularly strong influence. They then discovered that the balance of various properties in a resin composition can be controlled by adjusting the mass ratio of silicon atoms to sulfur atoms (Si / S). Here, a simpler approach is to adjust the mass ratio of the silicon-containing compound that provides silicon atoms to the resin composition and the sulfur-containing compound that provides sulfur atoms.

[0011] However, during the preparation of the resin composition or the manufacture of molded products from the resin composition, some silicon-containing compounds and / or sulfur-containing compounds may be incorporated into (bonded to) the ABS resin, decomposed, or dissipated (volatilized) from the resin composition, causing the content in the resin composition to change (decrease) from the initial amount, or making them undetectable. Therefore, it is practically difficult to determine the amount of silicon-containing compounds and sulfur-containing compounds that contribute to the expression of physical properties in the resin composition from the initial amount. The inventors have found that the optimal indicator for this determination is the mass ratio of sulfur atoms to silicon atoms (Si / S). Specifically, the resin composition of this embodiment contains silicon atoms (Si) and sulfur atoms (S) in addition to the above-mentioned ABS resin, and the mass ratio of silicon atoms to sulfur atoms (Si / S) is less than 1.

[0012] <<Silicon atoms (Si) and sulfur atoms (S)>> As described above, the silicon atoms contained in the resin composition originate from a silicon-containing compound. Examples of such silicon-containing compounds include at least one of the following: silicone oil, silicone resin, silane coupling agent, silica (e.g., fused silica). Among these, silicone oil is preferred as the silicon-containing compound. That is, it is preferable that the silicon atoms originate from silicone oil. Resin compositions containing a moderate amount of silicon-containing compound (especially silicone oil) tend to have a relatively high MFR. Therefore, the moldability of the resin composition can be improved. On the other hand, if the content of silicon-containing compound (especially silicone oil) in the resin composition is too high, the flexural strength and gloss of the molded product made from the resin composition tend to decrease.

[0013] Furthermore, as mentioned above, the sulfur atoms contained in the resin composition originate from sulfur-containing compounds. Examples of such sulfur-containing compounds include at least one of the following: sulfur-containing chain transfer agents, sulfur-containing fillers (e.g., barium sulfate, molybdenum sulfide), sulfur-containing coupling agents, sulfur-containing polymerization initiators, sulfur-containing emulsifiers, sulfur-containing reducing agents, sulfur-containing precipitating agents, sulfur-containing antioxidants, and the like. Among these, sulfur-containing compounds are preferably sulfur-containing chain transfer agents. In other words, it is preferable that the sulfur atoms originate from the sulfur-containing chain transfer agent. If there is too little sulfur-containing compound (especially sulfur-containing chain transfer agent), the molecular weight of the ABS resin increases, resulting in improved impact strength of the resin composition, but the MFR tends to decrease. Examples of such sulfur-containing chain transfer agents include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and ethyl thioglycolate.

[0014] The above mass ratio (Si / S) may be less than 1, but is preferably between 0.005 and less than 1, more preferably between 0.01 and 0.75, even more preferably between 0.015 and 0.5, even more preferably between 0.03 and 0.25, and particularly preferably between 0.045 and 0.1. By adjusting the mass ratio (Si / S) within this range, various properties are exhibited in a particularly well-balanced manner in the resin composition. In particular, even though the mass ratio (Si / S) is 0.005 or higher, meaning the content of silicon-containing compounds is low compared to the content of sulfur-containing compounds, the inclusion of silicon-containing compounds in the resin composition can suppress the deterioration of physical properties that are affected by sulfur-containing compounds.

[0015] The content of silicon atoms in the resin composition is preferably about 1000 ppm or less, more preferably about 750 ppm or less, still more preferably about 500 ppm or less, particularly preferably about 250 ppm or less, and most preferably about 100 ppm or less. The lower limit of the content of silicon atoms in the resin composition is usually about 10 ppm. The content of silicon atoms in the resin composition can be, for example, about 10 ppm or more and 1000 ppm or less. In this case, it can be determined that the resin composition appropriately contains a silicon-containing compound (particularly, silicone oil). For this reason, the MFR of the resin composition becomes high, and thus the molding processability can be improved. Further, the molded product produced from the resin composition is likely to have excellent flexural strength and glossiness. In this specification, the content of X in Y (mass% or ppm) means the ratio occupied by X when the whole of Y is 100 mass%.

[0016] The content of sulfur atoms in the resin composition is preferably about 2000 ppm or less, more preferably about 200 ppm or more and 1800 ppm or less, still more preferably about 300 ppm or more and 1600 ppm or less, and particularly preferably about 400 ppm or more and 1400 ppm or less. In this case, it can be determined that the resin composition appropriately contains a sulfur-containing compound (particularly, a sulfur-containing chain transfer agent). For this reason, it is possible to prevent the molecular weight of the ABS resin from becoming unnecessarily high, and thus it is possible to suppress a decrease in the MFR of the resin composition and maintain a sufficiently high impact strength.

[0017] <Method for producing the resin composition> The resin composition of this embodiment can be produced, for example, as follows. That is, first, a latex of a rubbery polymer is obtained by an emulsion polymerization method. Next, monomers such as vinyl cyanide monomers and aromatic vinyl monomers are added to this latex in one batch, batchwise, or continuously, and emulsion graft polymerization is carried out on the rubbery polymer to obtain a latex of the graft copolymer (A). Next, the graft copolymer (A) is precipitated (salting out) from this latex and recovered. Thereafter, the graft copolymer (A) is mixed with a copolymer (B) of monomers such as vinyl cyanide monomers and aromatic vinyl monomers.

[0018] <<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-ethylidene norbornene, and 1,4-cyclohexadiene; and, if necessary, aromatic vinyl monomers such as styrene, α-methylstyrene, and vinyltoluene, vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, acrylate monomers such as methyl acrylate, ethylhexyl acrylate, and octyl acrylate, methacrylate monomers such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate, and olefin monomers such as ethylene, propylene, 1-butene, isobutylene, and isobutylene, and copolymers showing rubbery elasticity copolymerized with the like. In one embodiment, the rubbery polymer is preferably polybutadiene.

[0019] By using the emulsion polymerization method for the preparation of the rubbery polymer, its 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 the emulsifier, and fatty acids or their salts (preferably higher fatty acids or their salts) can also be used. Anionic surfactants include carboxylic acid-type compounds and sulfate ester-type compounds. Specific examples include alkali metal salts of rosinic acid, alkyl sulfonates with 8 to 20 carbon atoms, alkylaryl sulfates, and condensates of sodium naphthalene sulfonate and formaldehyde.

[0020] Specific examples of nonionic surfactants include, for example, polyvinyl alcohol or its copolymers (e.g., copolymers with acrylamide), polyvinyl ether or its copolymers (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, for example, lauryldimethylaminoacetic acid betaine, lauramidopropyl betaine, hydroxyalkyl (12 to 14 carbon atoms) hydroxyethyl sarcosine, lauramidopropyl hydroxysulfobetaine, sodium cocoamphodiacetate, sodium lauaminopropionate, lauryldimethylamine oxide, and N-[3-alkyl(12,14)oxy-2-hydroxypropyl]-L-arginine hydrochloride.

[0021] Examples of fatty acids (higher fatty acids) or salts thereof include a first higher fatty acid having 12 to 14 carbon atoms or a salt thereof, a second higher fatty acid having 16 to 18 carbon atoms or a salt thereof, or mixtures thereof. The first higher fatty acid or its salt is considered 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 or 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 the salt of the first higher fatty acid, and sodium salts or potassium salts are more preferred. Furthermore, the first higher fatty acid or its salt may be either anhydrous or hydrated. 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 their salts, and more preferably at least one selected from lauric acid, myristic acid, and their salts.

[0022] The content of the first higher fatty acid or its salt in the resin composition is preferably less than 5000 ppm (10 ppm to less than 5000 ppm), more preferably 50 ppm to 4000 ppm, even more preferably 100 ppm to 3000 ppm, particularly preferably 300 ppm to 2000 ppm, and most preferably 500 ppm to 1000 ppm. In this case, the fluidity and heat resistance of the resin composition are easily improved. In this specification, when a higher fatty acid is a salt or hydrate, the content of the higher fatty acid or its salt shall be the value converted to the value of the higher fatty acid as a free acid. Furthermore, in this specification, unless otherwise specified, the content of each higher fatty acid or its salt refers to the proportion of each higher fatty acid or its salt in the entire resin composition.

[0023] The second higher fatty acid or its salt is considered to be a component that affects, for example, the fluidity and moldability (mold fouling) of the resulting resin composition. The second higher fatty acid may be either a saturated or 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 the salt of the second higher fatty acid, and sodium salts or potassium salts are more preferred. Furthermore, the second higher fatty acid or its salt may be either anhydrous or hydrated. 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 their salts, and more preferably at least one selected from palmitic acid, stearic acid, oleic acid, linoleic acid and their salts.

[0024] The content of the second higher fatty acid or its salt is preferably less than 12,000 ppm, more preferably between 500 ppm and 10,000 ppm, even more preferably between 1,000 ppm and 8,000 ppm, particularly preferably between 1,500 ppm and 6,000 ppm, and most preferably between 2,000 ppm and 4,000 ppm. In this case, the fluidity and moldability of the resin composition are easily improved. The second higher fatty acid or its salt preferably includes linoleic acid or its salt. Including linoleic acid or its salt can further improve the moldability of the resin composition. Also, the 1 The higher fatty acid or its salt preferably contains myristic acid or its salt. Myristic acid Alternatively, including a salt thereof can further improve the heat resistance of the resin composition.

[0025] The first higher fatty acid or its salt and the second higher fatty acid or its salt may include animal-derived higher fatty acids or their salts, but it is preferable that they include plant-derived higher fatty acids or their salts. By using plant-derived higher fatty acids or their salts, carbon dioxide emissions can be reduced, thereby lowering the environmental burden. Whether the first higher fatty acid or its salt and the second higher fatty acid or its salt include, and / or their content, higher fatty acids or their salts of plant origin is as defined in ASTM D6866. 14 This can be determined by measuring the biomass content using the 1C isotope assay method.

[0026] Furthermore, the plant-derived higher fatty acids or salts thereof preferably include higher fatty acids or salts thereof prepared from at least one of the following vegetable oils: 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, and linseed oil, and more preferably include higher fatty acids or salts thereof prepared from at least one of the following vegetable oils: palm oil, palm olein, and palm kernel oil. Specifically, higher fatty acids derived from plants or their salts can be obtained by appropriately mixing higher fatty acids or their salts prepared from two or more vegetable oils, or by adding a desired higher fatty acid or its salt to a higher fatty acid or its salt prepared from at least one vegetable oil. By using such a first higher fatty acid or its salt and a second higher fatty acid or its salt, the type and content of higher fatty acids or their salts contained in the resin composition can be easily adjusted to the desired range.

[0027] The volume-average particle diameter of the rubbery polymer is preferably between 250 nm and 400 nm, and more preferably between 300 nm and 500 nm. Furthermore, multiple types of rubbery polymers with different average particle diameters may be mixed and used. Such rubbery polymers can be produced by first obtaining a rubbery polymer with a small particle size (for example, a volume-average particle size of 100 nm or less) by emulsion polymerization, and then enlarging this small-particle-size rubbery polymer. Methods for enlarging in this case include, for example, applying shear force to the small-particle-size rubbery polymer using a Manton-Gorin homogenizer to cause aggregation and enlargement, or chemically enlarging the rubbery polymer by adding an acidic substance such as an inorganic acid, organic acid, or an acid group-containing copolymer to latex. Rubbery polymers produced by such methods are characterized by a broad particle size distribution.

[0028] Furthermore, rubbery polymers can be produced, for example, by using a method that involves emulsion polymerization and enlargement under conditions that reduce the number of particles by using a small amount of emulsifier. Rubbery polymers produced by this method are characterized by a narrow particle size distribution. The particle size of rubbery polymers can be measured by diluting the latex of the rubbery polymer with pure water and using a laser diffraction scattering particle size distribution analyzer (COULTER LS230). Furthermore, the particle size distribution of graft copolymer (A) can be measured by stirring 1 g of graft copolymer (A) in 100 g of dimethylformamide (DMF) for 24 hours, then adding more DMF to dilute it to an appropriate concentration (the concentration with the best sensitivity for measurement using the measuring instrument), and finally using a laser diffraction scattering particle size distribution analyzer.

[0029] Examples of aromatic vinyl monomers used in the graft copolymer (A) include styrene, α-methylstyrene, chlorostyrene, butylstyrene, vinyltoluene, and divinylstyrene. On the other hand, examples of vinyl cyanide monomers used in the graft copolymer (A) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Furthermore, vinyl monomers that can be copolymerized with these and used as needed in the graft copolymer (A) include, for example, (meth)acrylic acid ester monomers such as methyl (meth)acrylate and butyl (meth)acrylate, and maleimide monomers such as n-methylmaleimide and n-phenylmaleimide. In one embodiment, the graft copolymer (A) is preferably an acrylonitrile-butadiene-styrene copolymer (ABS resin).

[0030] The graft copolymer (A) is preferably obtained by emulsion graft polymerization of 30 to 90 parts by mass of a monomer mixture in the presence of 10 to 70 parts by mass of the above-mentioned rubbery polymer. By setting the amount of rubbery polymer within the above range, the appearance of the molded product can be improved, as well as the impact resistance and productivity of the resin composition. The monomer mixture preferably contains 10% to 40% by mass of vinyl cyanide monomers, 60% to 90% by mass of aromatic vinyl monomers, and 0% to 30% by mass of monomers copolymerizable with these. In emulsion graft polymerization, it is preferable to add a mixture of monomers, as well as, for example, a polymerization initiator, emulsifier, chain transfer agent, etc., to the latex of the rubbery polymer.

[0031] As polymerization initiators, at least one of the following can be used: 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. In addition to these polymerization initiators, reducing agents such as iron ions, secondary reducing agents such as sodium formaldehyde sulfoxylate, and chelating agents such as tetrasodium ethylenediaminetetraacetate can also be combined.

[0032] Various surfactants such as anionic surfactants, nonionic surfactants, and amphoteric surfactants can be used as emulsifiers, but it is preferable to use the first higher fatty acid or its salt, the second higher fatty acid or its salt, 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% by mass or more and 40% by mass or less, more preferably about 10% by mass or more and 35% by mass or less, and even more preferably about 15% by mass or more and 30% by mass or less. On the other hand, the content of the second higher fatty acid or its salt in the mixture is preferably about 60% by mass or more and 95% by mass or less, more preferably about 65% by mass or more and 90% by mass or less, and even more preferably about 70% by mass or more and 85% by mass or less.

[0033] 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, terpinolene, and the like. In this embodiment, as described above, sulfur-containing chain transfer agents such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and ethyl thioglycolate are preferably used as the chain transfer agent. By using a sulfur-containing chain transfer agent, it is easy to adjust the balance of various physical properties of the resulting resin composition.

[0034] The amount of emulsifier added when performing emulsion graft polymerization is preferably 0.1 parts by mass to 10 parts by mass, more preferably 0.5 parts by mass to 7.5 parts by mass, and even more preferably 1 part by mass to 5 parts by mass, per 100 parts by mass of the rubbery polymer. Furthermore, examples of precipitating agents used for precipitation (salting out) of the graft copolymer (A) include at least one selected from the group consisting of sulfuric acid, acetic acid, magnesium sulfate, hydrochloric acid, and calcium chloride. The temperature in emulsion graft polymerization is not particularly limited, but is preferably between 30°C and 90°C, more preferably between 40°C and 80°C, and even more preferably between 50°C and 70°C.

[0035] The graft copolymer (A) can be recovered by, for example, (i) dewatering the slurry (latex after the addition of a precipitating agent) using a centrifugal dewatering machine or press dewatering machine and then drying it with an air-flow dryer or the like, or (ii) simultaneously dewatering and drying using a compression dewatering machine or extruder or the like. Furthermore, the bulk density of the graft copolymer (A) was measured by placing the thoroughly dried graft copolymer (A) in a cylindrical container at 100 cm³. 3 This can be done by filling the container and measuring its mass. In this specification, the measurement of bulk density shall be performed in accordance with JIS K 6721:1977.

[0036] The content of the rubbery polymer in the graft copolymer (A) is preferably 40% to 70% by mass, and more preferably 45% to 65% by mass. In this case, the impact resistance of the graft copolymer (A) can be increased. The content of the rubbery polymer in the graft copolymer (A) can be adjusted, for example, by the ratio of aromatic vinyl monomers and vinyl cyanide monomers used to the rubbery polymer during emulsion graft polymerization. Furthermore, it is preferable that the constituent units of the graft copolymer (A), excluding the rubbery polymer, consist of approximately 65% ​​to 85% by mass of aromatic vinyl monomer units and approximately 15% to 35% by mass of vinyl cyanide monomer units. This configuration can further improve the impact resistance and chemical resistance of the graft copolymer (A).

[0037] The graft copolymer (A) is preferably in particulate form. The graft copolymer (A) is a rubbery polymer particle formed by graft copolymerization of aromatic vinyl monomers, vinyl cyanide monomers, etc., and is insoluble in organic solvents such as methyl ethyl ketone (MEK) and toluene, and is separated by centrifugation. Such particles are also called gel components. Furthermore, the graft copolymer (A) may also form an occlusion structure in which aromatic vinyl-vinyl cyanide copolymers are encapsulated in particulate form within the rubbery polymer particles. In a resin composition obtained by melt-blending a graft copolymer (A) and a copolymer (B), the gel component exists as a particulate dispersed phase within the continuous phase of copolymer (B).

[0038] The volume-average particle diameter of the graft copolymer (A), i.e., the volume-average particle diameter of the gel portion, is preferably about 0.1 μm to 1 μm, and more preferably about 0.15 μm to 0.5 μm. In this case, the impact resistance of the graft copolymer (A) is increased, and the appearance of the molded product tends to be good. In this specification, the volume-average particle size is calculated from image analysis of particles dispersed in a continuous phase, obtained by cutting ultrathin sections from pellets of a resin composition obtained by melt-blending graft copolymer (A) and copolymer (B), and observing them 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 be adjusted by the method of adding emulsifiers and the amount of water used during emulsion polymerization.

[0039] The grafting rate of the graft copolymer (A) is preferably 10% by mass or more and 100% by mass or less, and more preferably 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 grafting rate is a value calculated based on the gel content (G) and rubbery polymer content (RC) of the graft copolymer (A) using the formula: grafting rate (mass%) = [(G-RC) / RC] × 100. The graft ratio represents the amount of aromatic vinyl-vinyl cyanide copolymer and aromatic vinyl-vinyl cyanide copolymer contained in each unit mass of the rubbery polymer particles, which are bonded by grafts. The graft ratio can be adjusted, for example, during emulsion graft polymerization by setting the ratio of monomers to rubbery polymers, the type and amount of polymerization initiator, the amount of chain transfer agent, the amount of emulsifier, the polymerization temperature, the charging method (all at once / multi-stage / continuous), and the monomer addition rate.

[0040] The degree of toluene swelling of the graft copolymer (A) is preferably between 5 and 20 times. This further enhances the impact resistance of the graft copolymer (A) and makes it easier to obtain a good appearance for the molded product. In this specification, the degree of toluene swelling represents the degree of crosslinking of the rubbery polymer particles and is a value calculated from the ratio of the mass of the graft copolymer (A) in the toluene-swollen state to the mass of the dry state after removing the toluene by vacuum drying, after dissolving the graft copolymer (A) in toluene and separating the insoluble matter by centrifugation or filtration. Furthermore, the degree of toluene swelling is affected, for example, by the degree of crosslinking of the rubbery polymer used in emulsion graft polymerization. This can be adjusted by selecting the polymerization initiator and / or emulsifier during emulsion polymerization of the rubbery polymer, setting the polymerization temperature, and adding polyfunctional monomers such as divinylbenzene.

[0041] <<Copolymer (B)>> Copolymer (B) is a copolymer comprising an aromatic vinyl monomer, a vinyl cyanide monomer, and a vinyl monomer that can be copolymerized with these as needed. Examples of aromatic vinyl monomers used in copolymer (B) include styrene, α-methylstyrene, and vinyltoluene. On the other hand, examples of vinyl cyanide monomers used in copolymer (B) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. Furthermore, vinyl monomers that can be copolymerized with these and used as needed in copolymer (B) include, for example, (meth)acrylic acid ester monomers such as methyl (meth)acrylate and butyl (meth)acrylate, and maleimide monomers such as n-methylmaleimide and n-phenylmaleimide. In one embodiment, copolymer (B) is preferably an acrylonitrile-styrene copolymer (AS resin or SAN resin).

[0042] Copolymer (B) preferably contains 10% to 40% by mass of a vinyl cyanide monomer, 60% to 90% by mass of an aromatic vinyl monomer, and 0% to 30% by mass of a vinyl monomer copolymerizable with these. By setting the content of vinyl cyanide monomers within the above range, the moldability of the resin composition can be improved, as well as chemical resistance, impact resistance, and heat resistance. Furthermore, by setting the content of aromatic vinyl monomers within the above range, the moldability of the resin composition can be improved, as well as its impact resistance and chemical resistance. Furthermore, by setting the content of copolymerizable vinyl monomers within the above range, the balance of moldability, impact resistance, heat resistance, etc., of the resin composition can be improved.

[0043] 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 content of rubbery polymer in the resin composition is preferably 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 content of rubbery polymer in the resin composition is preferably 5% to 30% by mass. By setting the content of the graft copolymer (A) and the content of the rubbery polymer in the resin composition to the above ranges, the impact strength of the resin composition can be improved, as well as the moldability and rigidity can be enhanced, and the appearance of the molded product can be improved.

[0044] The resin composition is preferably used in pellet form by melt-kneading a graft copolymer (A) and 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 with twin rotors. Multiple of these extruders can also be used in combination. The extruder has, for example, a kneading section for melting and kneading graft copolymer (A) and copolymer (B), and at least one defoliation section. The graft copolymer (A) and copolymer (B) supplied to the extruder are first melted in the kneading section and kneaded to a uniform composition. The kneading section is composed of a combination of mixing elements such as kneading discs. Downstream of the kneading section, it is preferable to use an element that pushes the molten resin back to the upstream side, thereby filling the kneading section, from the viewpoint of kneadability. Examples of such elements include reverse lead full flight, reverse offset kneading, and seal rings.

[0045] The resin composition, melt-kneaded in the mixing section, is transported in a molten state to the defoliation section, where volatile components are defoliated by vacuum venting. The defoliated molten resin composition is extruded in a strand shape from a porous die and cut using methods such as cold cutting, air hot cutting, or underwater hot cutting to obtain pellet-shaped resin compositions. As a method of devolatilization extrusion, the water-injection devolatilization method, in which water is added before the devolatilization section, is preferred because it has excellent devolatilization efficiency. For example, one method is to melt-knead the graft copolymer (A) and copolymer (B) in the kneading section, then provide another kneading section to uniformly knead and disperse water in the molten resin composition, and then devolatilize the volatile components together with the water in the downstream devolatilization section. It is also preferable that the kneading section where water is added and mixed is filled to a similar state. The amount of water added is preferably 0.05% by mass or more and 2% by mass or less relative to the resin composition.

[0046] The cylinder temperature of the kneading and devolatilization sections of the extruder is not particularly limited, but is preferably between 150°C and 280°C, more preferably between 170°C and 260°C, and even more preferably between 190°C and 240°C. Setting a higher cylinder temperature makes it easier to increase the devolatilization efficiency of volatile components from the resin composition. Furthermore, it is preferable to set the pressure in the devolatilization section to approximately 10 mmHg or less if water is not added, and approximately 40 mmHg or less if water is added. Here, volatile components include monomers derived from graft copolymer (A) and copolymer (B), substances derived from solvent components, substances derived from monomer components produced by thermal decomposition, surfactants added as emulsifiers, substances derived from higher fatty acids or their salts, etc.

[0047] During the mixing process, additives such as lubricants, pigments, dyes, antioxidants, and UV absorbers, as well as 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 easier to adjust the balance of various physical properties of the resulting resin composition. In the resin composition manufacturing method described above, the mass ratio of silicon atoms to sulfur atoms (Si / S) in the resin composition can be adjusted by changing at least one of the following: the type and ratio of sulfur-containing chain transfer agent in the added chain transfer agent, the amount of chain transfer agent added, the type and ratio of silicone oil in the added lubricant, the amount of lubricant added, etc.

[0048] <Properties of resin compositions> The resin composition preferably has a melt mass flow rate (MFR) of approximately 10 g / 10 min or more, more preferably 13 g / 10 min or more, and even more preferably 15 g / 10 min or more, measured under conditions of 220°C and 10 kg load in accordance with JIS K 7210:1999 (ISO 1133:1997). The upper limit of the MFR of the resin composition is usually around 60 g / 10 min. The MFR of the resin composition can be, for example, between 10 g / 10 min and 60 g / 10 min. A resin composition having such a melt mass flow rate can be evaluated as having excellent fluidity and good moldability.

[0049] The resin composition preferably has a bending strength of approximately 62 MPa or higher, more preferably 72 MPa or higher, and even more preferably 82 MPa or higher, measured at a rate of 2 mm / min in accordance with JIS K 7171:2016 (ISO 178:2010). The upper limit of the bending strength of the resin composition is usually around 100 MPa. The bending strength of the resin composition can be, for example, between approximately 62 MPa and 100 MPa. Molded articles obtained from a resin composition having such bending strength can be judged to have excellent mechanical strength.

[0050] Furthermore, the resin composition preferably has a flexural modulus of approximately 1900 MPa or higher, more preferably 1950 MPa or higher, and even more preferably 2000 MPa or higher, measured at a rate of 2 mm / min in accordance with JIS K 7171:2016. The upper limit of the flexural modulus of the resin composition is usually around 2400 MPa. The flexural modulus of the resin composition can be, for example, between 1900 MPa and 2400 MPa. Molded articles obtained from resin compositions having such a flexural modulus can also be judged to have excellent rigidity.

[0051] The resin composition preferably has a tensile yield stress of approximately 40 MPa or more, more preferably approximately 42 MPa or more, and even more preferably approximately 44 MPa or more, measured at a rate of 50 mm / min in accordance with JIS K 7161-1, -2:2024 (ISO 527-1, -2:2019). The upper limit of the tensile yield stress of the resin composition is usually around 60 MPa. The tensile yield stress of the resin composition can be, for example, between approximately 40 MPa and 60 MPa. Molded articles obtained from a resin composition having such a tensile yield stress can be judged to have excellent load-bearing capacity.

[0052] Furthermore, the resin composition preferably has a tensile fracture stress of approximately 30 MPa or higher, more preferably approximately 32 MPa or higher, and even more preferably approximately 34 MPa or higher, measured at a rate of 50 mm / min in accordance with JIS K 7161-1, -2:2024. The upper limit of the tensile fracture stress of the resin composition is usually around 60 MPa. The tensile fracture stress of the resin composition can be, for example, between 30 MPa and 60 MPa. Molded articles obtained from resin compositions having such tensile fracture stress can also be judged to have excellent load-bearing capacity.

[0053] The resin composition preferably has a load deflection temperature of approximately 75°C or higher, more preferably approximately 77.5°C or higher, and even more preferably approximately 80°C or higher, measured under flatwidth and 1.8 MPa conditions in accordance with JIS K 7191-1, -2:2015 (ISO 75-1, -2:2013). The upper limit of the load deflection temperature of the resin composition is usually around 90°C. The load deflection temperature of the resin composition can be, for example, between approximately 75°C and 90°C. Molded articles obtained from resin compositions having such a load deflection temperature can be judged to have excellent heat resistance.

[0054] The resin composition has a Charpy impact strength of 20 kJ / m², measured at 23°C using a notched test specimen in accordance with JIS K 7111-1:2012. 2 It is preferable that it be around 24 kJ / m³2 More than 36kJ / m 2 It is more preferable that it be around 28 kJ / m³ 2 More than 32kJ / m 2 It is even more preferable that the Charpy impact strength is within the following range. Molded articles obtained from such a resin composition can be evaluated as having excellent impact resistance and toughness.

[0055] Furthermore, the resin composition preferably has a gloss level of 92% or higher, more preferably 94% or higher, even more preferably 96% or higher, and may be 100%, as measured at a 60° measuring angle in accordance with JIS Z 8741:1997. Molded articles obtained from such a resin composition can be evaluated as having extremely high gloss levels. Furthermore, they may be provided in the following embodiments.

[0056] (1) A resin composition comprising an acrylonitrile-butadiene-styrene copolymer (ABS resin), silicon atoms (Si), and sulfur atoms (S), wherein the mass ratio of silicon atoms to sulfur atoms (Si / S) is less than 1.

[0057] (2) A resin composition according to (1) above, wherein the mass ratio (Si / S) is 0.005 or more.

[0058] (3) A resin composition according to (1) or (2) above, wherein the content of silicon atoms in the resin composition is 1000 ppm or less.

[0059] (4) A resin composition according to any one of (1) to (3) above, wherein the content of sulfur atoms in the resin composition is 2000 ppm or less.

[0060] (5) A resin composition according to any one of (1) to (4) 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 10 g / 10 min or more.

[0061] (6) A resin composition according to any one of (1) to (5) above, wherein the bending strength measured at a rate of 2 mm / min in accordance with JIS K 7171:2016 is 62 MPa or more.

[0062] (7) A resin composition according to any one of (1) to (6) above, wherein the flexural modulus measured at a rate of 2 mm / min in accordance with JIS K 7171:2016 is 1900 MPa or higher.

[0063] (8) A resin composition according to any one of (1) to (7) above, wherein the tensile yield stress measured at a rate of 50 mm / min in accordance with JIS K 7161-1, -2:2024 is 40 MPa or more.

[0064] (9) A resin composition according to any one of (1) to (8) above, wherein the tensile fracture stress measured at a rate of 50 mm / min in accordance with JIS K 7161-1, -2:2024 is 30 MPa or more.

[0065] (10) A resin composition according to any one of (1) to (9) above, wherein the temperature of deflection under load measured flatwise and at 1.8 MPa in accordance with JIS K 7191-1, -2:2015 is 75°C or higher. Of course, this is not always the case.

[0066] Finally, while various embodiments relating to this disclosure have been described, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Examples]

[0067] The resin compositions will be described in more detail below based on the examples, but are not limited to these examples. 1. Production of polybutadiene (rubber-like polymer) First, 149 parts by mass of deionized water was added to an autoclave, and while stirring, 15 parts by mass of an 18% aqueous solution of potassium tallow fatty acid (emulsifier), 0.07 parts by mass of divinylbenzene (crosslinking agent), 0.19 parts by mass of t-dodecyl mercaptan (sulfur-containing 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.

[0068] Subsequently, 100 parts by mass of butadiene were added, and the temperature was raised to 60°C for 9 hours of polymerization. Then, the temperature was raised to 70°C for a further 6 hours of polymerization. After polymerization was complete, the pressure was removed to remove the remaining butadiene, and a small particle size polybutadiene latex was obtained. This polybutadiene latex was enlarged using a Manton-Gorin homogenizer (pressure-assisted flocculation and enlargement machine) to obtain polybutadiene latex. The obtained polybutadiene latex had a solid content of 39% by mass and a volume-average particle size of 330 nm.

[0069] 2. Manufacturing of grafted ABS resin (grafted copolymer (A)) First, 100 parts by mass of polybutadiene latex was added to an autoclave, and while stirring, 3 parts by mass of acrylonitrile, 8 parts by mass of styrene, 0.1 parts by mass of t-dodecyl mercaptan (sulfur-containing chain transfer agent), and 50 parts by mass of deionized water were added and the temperature was raised. After reaching 50°C, polymerization was started by adding 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). Forty minutes after reaching 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.

[0070] Furthermore, a mixture of 0.1 parts by mass of diisopropylbenzene hydroperoxide (polymerization initiator: manufactured by Nippon Oil & Fats Co., Ltd., "Parkmil P"), 0.2 parts by mass of t-butyl peroxyacetate (polymerization initiator: manufactured by Arkema Yoshitomi Co., Ltd., "Lupazol-70"), 3 parts by mass of an 18% aqueous solution of potassium tallow fatty acid (emulsifier), 10 parts by mass of acrylonitrile, 22 parts by mass of styrene, 0.4 parts by mass of t-dodecyl mercaptan (sulfur-containing 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 complete, the mixture was stirred at 70°C for 2 hours to complete the polymerization. Magnesium sulfate and sulfuric acid (precipitating agent) were added to this latex to precipitate (salt-out) and obtain grafted ABS resin.

[0071] 3. Manufacturing of AS resin (polymer (B)) [Manufacturing of AS resin (B-1)] The feed solution to be supplied to the 50L reaction vessel was prepared to consist of 55 parts by mass of styrene, 20 parts by mass of acrylonitrile, 25 parts by mass of ethylbenzene, 0.02 parts by mass of t-butyl peroxyisopropyl carbonate (polymerization initiator) as a polymerization initiator, and 0.04 parts by mass of n-dodecyl mercaptan (sulfur-containing chain transfer agent) as a chain transfer agent. After bubbling the feed solution with nitrogen gas and passing through a mixer, it was continuously supplied to the reaction vessel at a rate of 10 L / hour into the liquid phase of the polymerization solution. The polymerization temperature was maintained at 143°C, and the reaction solution filling rate in the reaction vessel was maintained at 60 vol%, with an equal amount of reaction solution being continuously withdrawn. The evaporated gas generated in the reaction vessel was condensed in a heat exchanger outside the vessel, and the condensed liquid was returned to the liquid phase of the reaction vessel. The extracted reaction solution was introduced into a volatile matter removal apparatus maintained at 250°C and a high vacuum of 10 mmHg, where unreacted monomers and organic solvents were devolved and recovered to obtain pelletized AS resin (B-1).

[0072] [Manufacturing of AS resin (B-2)] Pellets of AS resin (B-2) were obtained in the same manner as AS resin (B-1), except that the amount of t-dodecyl mercaptan (sulfur-containing chain transfer agent) added was changed to 0.01 parts by mass.

[0073] 4. Manufacturing of resin compositions (Example 1) A pelletized resin composition was produced by blending 30 parts by mass of grafted ABS resin, 70 parts by mass of AS resin (B-1), and 0.25 parts by mass of silicone oil (silicone-containing compound) with a total of 100 parts by mass of these resins, and melt-kneading the mixture at a temperature of 220°C using a twin-screw extruder. In order to remove any remaining volatile components, defloration was performed by vacuum venting and water injection defloration.

[0074] (Example 2) A pelletized resin composition was prepared in the same manner as in Example 1, except that the amount of silicone oil was changed to 0.025 parts by mass. (Example 3) A pelletized resin composition was prepared in the same manner as in Example 1, except that the silicone oil was omitted.

[0075] (Example 4) A pelletized resin composition was prepared in the same manner as in Example 1, except that 42 parts by mass of grafted ABS resin, 58 parts by mass of AS resin (B-1), and 0.03 parts by mass of silicone oil were blended with a total of 100 parts by mass of these resins. (Comparative Example 1) A pelletized resin composition was prepared in the same manner as in Example 1, except that 30 parts by mass of grafted ABS resin, 70 parts by mass of AS resin (B-2), and 0.25 parts by mass of silicone oil were blended with a total of 100 parts by mass of these resins.

[0076] 5. Measurement and Evaluation 5-1. Measurement of silicon atom (Si) and sulfur atom (S) content in resin compositions The silicon atom (Si) and sulfur atom (S) content in the resin compositions of each example and comparative example was measured using the fundamental parameter method with a scanning X-ray fluorescence analyzer (ZSX Primus III NEXT, Rigaku Corporation). 5-2. Measurement of Melt Mass Flow Rate (MFR) The melt mass flow rate (MFR) of the resin compositions in each example and comparative example was measured in accordance with JIS K 7210:1999 under conditions of 220°C and 10 kg load.

[0077] 5-3. Measurement of tensile yield stress and tensile fracture stress The tensile yield stress and tensile fracture stress of the resin compositions of each example and comparative example were measured as follows. First, using the resin composition, dumbbell-shaped test specimens were prepared using an injection molding machine (manufactured by Nippon Steel Corporation, model "J140AD-180H"). For these test specimens, the tensile yield stress and tensile fracture stress were measured using a tensile testing machine (manufactured by Intesco Corporation, model "210X-3 universal testing machine") under test conditions of 50 mm / min, in accordance with JIS K 7161-1, -2:2024.

[0078] 5-4. Measurement of Bending Strength The flexural strength of the resin compositions in each example and comparative example was measured as follows. Using a resin composition, dumbbell-shaped samples were prepared using an injection molding machine (Nippon Steel Corporation, "J140AD-180H"). The bending strength of these samples was measured using a bending test machine (Toyo Seiki Co., Ltd., "Bendgraph II") under test conditions of 2 mm / min, in accordance with JIS K 7171:2016.

[0079] 5-5. Measurement of Flexural Modulus The flexural modulus of the resin compositions in each example and comparative example was determined in accordance with JIS K 7171:2016 by the following method. Specifically, a fully automatic bending tester (Toyo Seiki Seisakusho Co., Ltd., "Bendograph") and a test specimen (length 80 mm, width 10 mm, thickness 4 mm) obtained by molding the resin composition were used, and the measurement was taken by bending the test specimen at a bending speed of 2 mm / min with a support distance of 64 mm. 5-6. Measurement of Charpy impact strength The Charpy impact strength of the resin compositions in each example and comparative example was measured at 23°C using notched test specimens in accordance with JIS K 7111-1:2012.

[0080] 5-7. Measurement of load deflection temperature The load deflection temperature of the resin compositions in each example and comparative example was measured flatwise under conditions of 1.8 MPa, in accordance with JIS K 7191-1, -2:2015. 5-8. Measurement of Glossiness The gloss of the resin compositions in each example and comparative example was measured at a 60° measurement angle in accordance with JIS Z 8741:1997.

[0081] These results are shown in Table 1 below. [Table 1]

[0082] As shown in Table 1, the resin composition of Example 2 had a slightly lower Charpy impact strength, but other physical properties were good, demonstrating an excellent balance of various physical properties. Similarly, the resin composition of Example 4 had slightly lower physical properties other than Charpy impact strength, but its Charpy impact strength was extremely good, and it also demonstrated an excellent balance of various physical properties. The resin compositions of Examples 1 and 3 had slightly lower Charpy impact strength and at least one other physical property, resulting in a poorer balance of physical properties compared to the resin compositions of Examples 2 and 4. In contrast, the resin composition of Comparative Example 1 had a mass ratio (Si / S) of 1 or more, a clearly low MFR, and did not exhibit a sufficiently high Charpy impact strength, resulting in a poor balance of various physical properties compared to the resin composition of the example.

Claims

1. A resin composition, It contains an acrylonitrile-butadiene-styrene copolymer (ABS resin), silicone oil or its decomposition products, and a sulfur-containing chain transfer agent or its decomposition products. The mass ratio of silicon atoms (Si) to sulfur atoms (S) in the resin composition (Si / S) is 0.005 or more and 0.25 or less. A resin composition wherein the content of sulfur atoms in the resin composition is 1270 ppm or more and 2000 ppm or less.

2. In the resin composition according to claim 1, A resin composition having a mass ratio (Si / S) of 0.1 or less.

3. In the resin composition according to claim 1, A resin composition in which the content of silicon atoms is 90 ppm or more and 1000 ppm or less.

4. In the resin composition according to claim 1, A resin composition having a melt mass flow rate (MFR) of 10 g / 10 min or more, measured under conditions of 220°C and 10 kg load, in accordance with JIS K 7210:1999.

5. In the resin composition according to claim 1, A resin composition having a bending strength of 62 MPa or more, measured under conditions of 2 mm / min in accordance with JIS K 7171:2016.

6. In the resin composition according to claim 1, A resin composition having a flexural modulus of 1900 MPa or higher, measured at a density of 2 mm / min in accordance with JIS K 7171:2016.

7. In the resin composition according to claim 1, A resin composition having a tensile yield stress of 40 MPa or more, measured at a density of 50 mm / min in accordance with JIS K 7161-1, -2:2024.

8. In the resin composition according to claim 1, A resin composition having a tensile fracture stress of 30 MPa or more, measured at a density of 50 mm / min in accordance with JIS K 7161-1, -2:2024.

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

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