Flame-retardant styrene resin composition and molded article

Abstract

To provide a flame-retardant styrenic resin composition that excels in flame retardancy, impact resistance, weather resistance, and low dielectric property, and a molded article comprising the flame-retardant styrenic resin composition.SOLUTION: A flame-retardant styrenic resin composition comprises 45-96 mass% of a styrenic resin (A), 3-25 mass% of a silicone / acryl composite rubber graft copolymer (B) with a vinyl polymer composed of one or more vinyl monomer units grafted to a composite rubber comprising polyorganosiloxane and polyalkyl (meth)acrylate, and 1-30 mass% of a phosphonate compound or a phosphinic acid compound (C).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a flame-retardant styrene-based resin composition and a molded product containing the flame-retardant styrene-based resin composition.

Background Art

[0002] Styrene-based resins are used in a wide range of applications because they are excellent in moldability, dimensional stability, and impact resistance in addition to their impact resistance. Among them, polystyrene-based resin compositions imparted with flame retardancy are used in a wide variety of applications including home appliances and OA equipment. At present, thinning of products is required due to reduction or weight reduction. Conventionally, various flame retardants have been proposed to impart flame retardancy to styrene-based resins. Among them, bromine-based flame retardants, which are inexpensive and have an excellent balance of physical properties, are widely used. However, due to the recent active movement to regulate halogen-containing organic compounds, especially in Europe, the demand for flame-retardant resins or flame-retardant resin compositions that do not contain bromine elements is increasing. In recent years, the use of styrene-based resins in high-frequency applications such as next-generation mobile communications that take advantage of their low dielectric properties has been studied.

[0003] However, under outdoor use or under high-temperature and high-humidity use, styrene-based resin products imparted with flame retardancy are significantly discolored or have a reduced impact strength, and their use may be restricted. In order to solve such problems, various proposals have been made, such as specific flame-retardant formulations and the addition of rubber-like elastic bodies.

[0004] For example, Patent Documents 1 and 2 disclose a flame-retardant resin composition in which a phosphinate compound and a hindered amine compound are blended with a styrene-based resin. Further, Patent Document 3 discloses a flame-retardant thermoplastic resin composition in which a specific organic phosphorus compound and a specific composite rubber-based graft copolymer are blended with a rubber-reinforced polystyrene-based resin.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-7565 [Patent Document 2] Japanese Patent Publication No. 2022-69320 [Patent Document 3] Japanese Patent Publication No. 2000-212385 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, while the technologies described in Patent Documents 1 and 2 can improve the light resistance of styrene resins and prevent discoloration due to light, they may be unusable in outdoor applications where they are affected by temperature changes and weather conditions such as rain due to a significant decrease in impact strength. Furthermore, Patent Document 3 discloses the addition of a specific composite rubber-based graft copolymer to improve impact strength. However, while the technology in Patent Document 3 can prevent discoloration due to light, it is unusable in outdoor applications where it is affected by temperature changes and weather conditions such as rain due to a decrease in impact strength, and the specific organophosphorus compound used also has the problem of inhibiting low dielectric properties.

[0007] Therefore, the present disclosure aims to provide a flame-retardant styrene-based resin composition that is excellent in flame retardancy, impact resistance, weather resistance, and low dielectric properties, and a molded article containing the flame-retardant styrene-based resin composition. [Means for solving the problem]

[0008] The inventors of the present invention have conducted diligent studies to solve the above problems and have found that a styrene-based resin (A) and We have discovered that a flame-retardant styrene-based resin composition with excellent flame retardancy, impact resistance, weather resistance, and low dielectric properties can be obtained by including predetermined amounts of a silicone / acrylic composite rubber graft copolymer (B), in which a vinyl polymer composed of one or more vinyl monomer units is grafted onto a composite rubber containing polyorganosiloxane and polyalkyl (meth)acrylate, and a phosphonic acid ester compound or phosphinic acid compound (C), respectively. This has led to the completion of the present invention.

[0009] In other words, the present invention is as follows. [1] A flame-retardant styrene resin composition characterized by containing 45 to 96% by mass of a styrene resin (A), 3 to 25% by mass of a silicone / acrylic composite rubber graft copolymer (B) in which a vinyl polymer composed of one or more vinyl monomer units is grafted onto a composite rubber containing polyorganosiloxane and polyalkyl (meth)acrylate, and 1 to 30% by mass of a phosphonic acid ester compound or phosphinic acid compound (C).

[0010] [2] The flame-retardant styrene resin composition according to [1], wherein the styrene resin (A) is a styrene copolymer resin containing one or more monomer units selected from the group consisting of methacrylic acid monomer units, alkyl methacrylate monomer units, and maleic anhydride monomer units.

[0011] [3] The flame-retardant styrene resin composition according to either [1] or [2], wherein the average particle size of the silicone / acrylic composite rubber graft copolymer (A) is 0.5 to 1.2 μm.

[0012] [4] A flame-retardant styrene resin composition according to either [1] or [2], further comprising 0.05 to 3 parts by mass of a hindered amine compound (D) and / or an ultraviolet absorber (E).

[0013] [5] The flame-retardant styrene resin composition according to [4], wherein the hindered amine compound (D) is a NOR-type hindered amine compound.

[0014] A molded article characterized by comprising the flame-retardant styrene resin composition described in either item [6][1] or [2]. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a flame-retardant styrene-based resin composition that is excellent in flame retardancy, impact resistance, weather resistance, and low dielectric properties, and a molded article containing the flame-retardant styrene-based resin composition. [Modes for carrying out the invention]

[0016] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below, but the present invention is not limited to the following description and can be implemented in various ways within the scope of its gist.

[0017] [Flame-retardant styrene resin composition] The flame-retardant styrene resin composition of this embodiment is characterized by containing 45 to 96% by mass of a styrene resin (A), 3 to 25% by mass of a silicone / acrylic composite rubber graft copolymer (B) in which a vinyl polymer composed of one or more vinyl monomer units is grafted onto a composite rubber containing polyorganosiloxane and polyalkyl (meth)acrylate, and 1 to 30% by mass of a phosphonic acid ester compound or phosphinic acid compound (C). This results in a flame-retardant styrene-based resin composition with excellent flame retardancy, impact resistance, weather resistance, and low dielectric properties.

[0018] <Styrene resin (A): Component (A)> In the flame-retardant styrene-based resin composition of this embodiment, the content of styrene-based resin (A) is 45 to 96% by mass, preferably 55 to 94% by mass, and more preferably 60 to 92% by mass. By setting the content to 45% by mass or more, low dielectric properties can be maintained. Furthermore, by setting the content to 96% by mass or less, flame retardancy and impact resistance can be obtained.

[0019] The styrene-based resin (A) that can be used in this embodiment is preferably a resin obtained by polymerizing a styrene-based monomer and, if necessary, one or more monomers selected from other vinyl-based monomers copolymerizable with the styrene-based monomer and rubbery polymers (a1). In particular, from the viewpoint of weather resistance, the styrene-based resin (A) is more preferably a styrene copolymer containing a styrene-based monomer homopolymer (= polystyrene), a rubber-modified styrene-based resin, or a styrene-based monomer and one or more monomer units selected from the group consisting of methacrylic acid monomer units, alkyl methacrylate monomer units, and maleic anhydride monomer units. The following describes in detail the preferred forms of styrene-based resin (A): polystyrene, rubber-modified styrene-based resin, and styrene copolymer resin.

[0020] <Polystyrene> In this embodiment, polystyrene is a styrene monomer homopolymer obtained by polymerizing styrene monomers, and commonly available ones can be appropriately selected and used. Examples of styrene monomers constituting polystyrene include, in addition to styrene, α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and styrene derivatives such as t-butylstyrene or bromostyrene and indene. Styrene is particularly preferred from an industrial standpoint. One or more of these styrene monomers can be used. Polystyrene may further contain monomer units other than the above-mentioned styrene monomer units, as long as it does not impair the effects of the present invention, but it typically consists of styrene monomer units.

[0021] <<Rubber-modified styrene resin>> In this embodiment, the rubber-modified styrene resin is a matrix resin having styrene monomer units in which particles of a rubbery polymer (a1) (hereinafter referred to as rubbery polymer particles (1)) are dispersed, and it can be produced by polymerizing styrene monomers in the presence of the rubbery polymer (a1).

[0022] In addition to styrene, the styrene monomers constituting the rubber-modified styrene resin of this embodiment include, for example, α-methylstyrene, α-methylp-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and styrene derivatives such as t-butylstyrene or bromostyrene and indene. Styrene is particularly preferred. One or more of these styrene monomers can be used.

[0023] The rubber-like polymer (a1) contained in the rubber-modified styrene resin of this embodiment may, for example, have a resin containing styrene monomer units obtained from the above-mentioned styrene monomer encapsulated inside the particles of the rubber-like polymer (a1) (including salami structure and core-shell structure), and / or the surface of the rubber-like polymer particles (1) may be grafted with a resin containing styrene monomer units.

[0024] As the rubbery polymer (a1), for example, rubber components such as polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer can be used. In addition, the rubber component may include polystyrene and / or This may include forms containing polystyrene-unsaturated carboxylic acid polymers, etc. Among these, the rubbery polymer (a1) is preferably polybutadiene or styrene-butadiene copolymer. For polybutadiene, both high-cis polybutadiene with a high cis content and low-cis polybutadiene with a low cis content can be used. Furthermore, both random and block structures can be used for the styrene-butadiene copolymer. One or more of these rubbery polymers (a1) can be used. Also, saturated rubber obtained by hydrogenating butadiene rubber can be used.

[0025] Examples of such rubber-modified styrene resins include HIPS (high-impact polystyrene), ABS resin (acrylonitrile-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), and AES resin (acrylonitrile-ethylene propylene rubber-styrene copolymer).

[0026] When the rubber-modified styrene resin is a HIPS resin, among these rubbery polymers (a1), high-cis polybutadiene composed of 90 mol% or more cis-1,4 bonds is particularly preferred. In the high-cis polybutadiene, it is preferable that vinyl-1,2 bonds be composed of 6 mol% or less, and particularly preferable that they be composed of 3 mol% or less.

[0027] Furthermore, the content of isomers of the constituent units of the above-mentioned isis-polybutadiene that have a cis-1,4 structure, a trans-1,4 structure, or a vinyl-1,2 structure can be calculated by measuring with an infrared spectrophotometer and processing the data using the Morello method.

[0028] Furthermore, the above-mentioned high-cis polybutadiene can be easily obtained by polymerizing 1,3-butadiene using a known production method, for example, a catalyst containing an organoaluminum compound and a cobalt or nickel compound.

[0029] The content of the rubber-like polymer (a1) in the rubber-modified styrene resin is preferably 3 to 20 parts by mass, and more preferably 5 to 15 parts by mass, per 100 parts by mass of the total amount of the rubber-modified styrene resin. If the content of the rubber-like polymer (a1) is less than 3 parts by mass, the impact resistance of the styrene resin (A) may decrease. Also, if the content of the rubber-like polymer (a1) exceeds 20 parts by mass, the flame retardancy may decrease.

[0030] In this disclosure, the content of the rubbery polymer (a1) contained in the rubber-modified styrene resin is a value calculated using pyrolysis gas chromatography.

[0031] The average particle size of the rubbery polymer particles (1) contained in the rubber-modified styrene resin is preferably 0.5 to 4.0 μm, and more preferably 0.8 to 3.5 μm, from the viewpoint of impact resistance and flame retardancy.

[0032] In this disclosure, the average particle size of the rubbery polymer particles (1) contained in the rubber-modified styrene resin can be measured by the following method. Ultrathin sections with a thickness of 75 nm were prepared from a rubber-modified styrene resin stained with osmium tetroxide, and photographs were taken at a magnification of 10,000x using an electron microscope. In the photograph, the black-stained particles are the rubbery polymer (a1). From the photograph, the following formula (N1) was derived: Average particle diameter=ΣniDri 3 / ΣniDri 2 (N1) (In the above formula (N1), ni is the number of particles of the rubbery polymer (a1) with particle size Dri (= rubbery polymer particle (1)), and particle size Dri is the particle size calculated as the equivalent circle diameter from the area of ​​the particles in the photograph.) The area-average particle diameter is calculated and used as the average particle diameter of the rubbery polymer particles (1). This measurement involves scanning a photograph at a resolution of 200 dpi and analyzing it using the image analysis device IP-1000. The measurement is performed using particle analysis software manufactured by Asahi Kasei Corporation.

[0033] The reduced viscosity of the rubber-modified styrene resin (which is an indicator of the molecular weight of the rubber-modified styrene resin) is preferably in the range of 0.50 to 0.85 dL / g, and more preferably in the range of 0.55 to 0.80 dL / g. If it is less than 0.50 dL / g, the impact strength may decrease, and if it exceeds 0.85 dL / g, the moldability may decrease due to a decrease in fluidity. In this disclosure, the reduced viscosity of the rubber-modified styrene resin is the value measured in a toluene solution at 30°C and a concentration of 0.5 g / dL. The method for producing rubber-modified styrene resins is not particularly limited, but they can be produced by bulk polymerization (or solution polymerization) in which styrene monomers (and solvents) are polymerized in the presence of a rubbery polymer (a1), bulk-suspension polymerization in which the reaction transitions to suspension polymerization, or emulsion graft polymerization in which styrene monomers are polymerized in the presence of a rubbery polymer (a1) latex. In bulk polymerization, the resin can be produced by continuously supplying a mixed solution of the rubbery polymer (a1), styrene monomers, and optionally an organic solvent, organic peroxide, and / or chain transfer agent to a polymerization apparatus configured by connecting a fully mixed reactor or a tank reactor and multiple tank reactors in series.

[0034] <Styrene-based copolymer resin> In this embodiment, the styrene copolymer resin is a resin containing styrene monomer units and other monomer units copolymerizable with the styrene monomer units (for example, unsaturated carboxylic acid monomer units). For example, when the other monomer units are unsaturated carboxylic acid monomer units, the styrene copolymer resin according to the present invention preferably contains 69 to 98% by mass, more preferably 74 to 96% by mass, and even more preferably 77 to 92% by mass, when the total content of styrene monomer units and unsaturated carboxylic acid monomer units is 100% by mass. By setting the content to 69% by mass or more, the fluidity of the resin can be improved. On the other hand, by setting the content of styrene monomer units to 98% by mass or less, it becomes difficult to have a desired amount of unsaturated carboxylic acid monomer units, which are an example of other monomers, and it becomes difficult to obtain the effects of these monomer units described later. Furthermore, in this embodiment, the use of a styrene copolymer improves the dispersibility and interfacial adhesion of the silicone / acrylic composite rubber graft copolymer (B), thereby improving its impact strength and weather resistance. In this embodiment, the unsaturated carboxylic acid monomer includes unsaturated carboxylic acid monomers and unsaturated carboxylic acid ester monomers.

[0035] In the preferred styrene copolymer resin of this embodiment, unsaturated carboxylic acid monomer units play a role in improving heat resistance. When the total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units in the styrene copolymer resin is 100% by mass, the content of unsaturated carboxylic acid monomer units is preferably 2 to 16% by mass, more preferably 4 to 14% by mass, and even more preferably 8 to 13% by mass. By setting the content to 2% by mass or more, the dispersibility of component (C) and interfacial adhesion with the silicone / acrylic composite rubber graft copolymer (B) are improved, improving flame retardancy and impact resistance, as well as further improving heat resistance. On the other hand, by setting the content to 16% by mass or less, low dielectric properties are maintained and mechanical properties are further improved.

[0036] Generally, styrene-methacrylic acid-methyl methacrylate copolymer resins, which are one form of the styrene-based copolymer resin in the present invention, are almost always produced by radical polymerization on an industrial scale. However, in this embodiment, various alcohols can be added to the polymerization system to suppress the gelation reaction in the defoliation step.

[0037] Unsaturated carboxylic acid ester monomers can be used to suppress the dehydration reaction of unsaturated carboxylic acid monomers through intermolecular interactions and to improve the mechanical strength of resins. Furthermore, unsaturated carboxylic acid ester monomers also contribute to improving resin properties such as weather resistance and surface hardness.

[0038] In this embodiment, when the total content of styrene monomer units, unsaturated carboxylic acid monomer units, and unsaturated carboxylic acid ester monomer units is set to 100% by mass, the content of unsaturated carboxylic acid ester monomer units is preferably 0 to 15% by mass, more preferably 1 to 12% by mass, and even more preferably 2 to 10% by mass. By setting the content to 15% by mass or less, water absorption can be suppressed and low dielectric properties can be maintained. Furthermore, by setting the lower limit of the content of unsaturated carboxylic acid ester monomer units to 0% by mass, heat resistance can be improved and costs can be reduced, but from the above viewpoint, the content of unsaturated carboxylic acid ester monomer units can also be greater than 0% by mass.

[0039] Furthermore, when unsaturated carboxylic acid monomers and unsaturated carboxylic acid ester monomer units are bonded adjacent to each other in a polymer chain, a de-alcoholization reaction may occur under certain conditions when a high-temperature, high-vacuum defloration apparatus is used, forming a six-membered cyclic acid anhydride. The styrene copolymer resin of this embodiment may contain this six-membered cyclic acid anhydride, but it is preferable to have as little of the generated six-membered cyclic acid anhydride as possible, as it reduces fluidity.

[0040] In this embodiment, the content of styrene monomer units (e.g., styrene monomer units), unsaturated carboxylic acid monomer units (e.g., methacrylic acid monomer units), and unsaturated carboxylic acid ester monomer units (e.g., methyl methacrylate monomer units) in the styrene copolymer resin is determined by proton nuclear magnetic resonance ( 1 It can be determined from the integral ratio of the spectrum measured with a 1H-NMR detector.

[0041] In this embodiment, the styrene copolymer resin may further contain monomer units other than styrene monomer units and, as an example of other monomers, unsaturated carboxylic acid monomers (e.g., unsaturated carboxylic acid monomer units and unsaturated carboxylic acid ester monomer units), to the extent that it does not impair the effects of the present invention. However, the styrene copolymer resin in the present invention is preferably typically composed of styrene monomer units, unsaturated carboxylic acid monomer units, and / or unsaturated carboxylic acid ester monomer units.

[0042] The styrene monomer constituting the styrene copolymer resin of this embodiment is not particularly limited, but examples include styrene, α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, t-butylstyrene, bromostyrene, indene, and other styrene derivatives. From an industrial standpoint, styrene is preferred as the styrene monomer. These styrene monomers can be used individually or in combination of two or more.

[0043] The unsaturated carboxylic acid monomers constituting the styrene copolymer resin of this embodiment are not particularly limited, but examples include methacrylic acid, acrylic acid, maleic anhydride, maleic acid, fumaric acid, itaconic acid, etc. Methacrylic acid is preferred as the unsaturated carboxylic acid monomer because it has a significant effect in improving heat resistance and is liquid at room temperature, making it easy to handle. These unsaturated carboxylic acid monomers can be used individually or in combination of two or more.

[0044] The styrene copolymer resin of this embodiment is composed of an unsaturated carboxylic acid ester monomer and Examples of such monomers, though not particularly limited, include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and cyclohexyl (meth)acrylate. Methyl (meth)acrylate is preferred as the (meth)acrylate monomer because it has little effect on the reduction of heat resistance. These unsaturated carboxylic acid ester monomers can be used individually or in combination of two or more.

[0045] Suitable styrene-based copolymer resins for this embodiment include styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-methacrylic acid-methyl methacrylate copolymer, styrene-acrylic acid copolymer, styrene-methyl acrylate copolymer, styrene-acrylic acid-methyl acrylate copolymer, styrene-methyl methacrylate-butyl methacrylate copolymer, styrene-butyl methacrylate copolymer, or styrene-maleic anhydride copolymer.

[0046] In this embodiment, the weight-average molecular weight (Mw) of the styrene copolymer resin is preferably 100,000 to 350,000, more preferably 120,000 to 300,000, and even more preferably 140,000 to 240,000. When the weight-average molecular weight (Mw) is 100,000 to 350,000, a resin with a better balance of mechanical strength and fluidity is obtained, and the inclusion of gel material is also reduced. The weight-average molecular weight (Mw) is a value obtained on a standard polystyrene basis using gel permeation chromatography.

[0047] In this embodiment, there are no particular limitations on the polymerization method of the styrene copolymer resin, but for example, a bulk polymerization method or a solution polymerization method can be suitably employed as a radical polymerization method. The polymerization method mainly comprises a polymerization step of polymerizing the polymerization raw materials (monomer components) and a defoliation step of removing volatile components such as unreacted monomers and polymerization solvents from the polymerization product.

[0048] The following describes an example of a polymerization method for styrene copolymer resins that can be used in this embodiment. When polymerizing polymerization raw materials to obtain styrene copolymer resins, the polymerization raw material composition typically contains a polymerization initiator and a chain transfer agent. Polymerization initiators used in the polymerization of styrene copolymer resins include organic peroxides, such as peroxyketals like 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, and n-butyl-4,4-bis(t-butylperoxy)valerate; dialkyl peroxides like di-t-butylperoxide, t-butylcumylperoxide, and dicumylperoxide; diacyl peroxides like acetylperoxide and isobutyrylperoxide; peroxydicarbonates like diisopropylperoxydicarbonate; peroxyesters like t-butylperoxyacetate; ketone peroxides like acetylacetone peroxide; and hydroperoxides like t-butylhydroperoxide. Of these, 1,1-bis(t-butylperoxy)cyclohexane is preferred from the viewpoint of decomposition rate and polymerization rate.

[0049] Examples of chain transfer agents used in the polymerization of styrene copolymer resins include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan.

[0050] In this embodiment, solution polymerization using a polymerization solvent can be employed as the polymerization method for the styrene copolymer resin, if necessary. Examples of polymerization solvents that can be used include aromatic hydrocarbons, such as ethylbenzene, and dialkyl ketones, such as methyl ethyl ketone. These can be used individually or in combination of two or more. Other polymerization solvents, such as aliphatic hydrocarbons, can be further mixed with aromatic hydrocarbons, provided that they do not reduce the solubility of the polymerization product. It is preferable to use these polymerization solvents in an amount not exceeding 25 parts by mass per 100 parts by mass of total monomers. If the amount of polymerization solvent exceeds 25 parts by mass per 100 parts by mass of total monomers, the polymerization rate tends to decrease significantly, and the mechanical strength of the resulting resin tends to decrease greatly. Adding the polymerization solvent at a ratio of 5 to 20 parts by mass per 100 parts by mass of total monomers before polymerization is preferable in terms of ensuring uniform quality and controlling the polymerization temperature.

[0051] In this embodiment, there are no particular restrictions on the apparatus used in the polymerization step to obtain the styrene copolymer resin, and it may be appropriately selected according to the polymerization method of the styrene copolymer resin. For example, when bulk polymerization is employed, one or more fully mixed reactors can be used in the polymerization apparatus. There are also no particular restrictions on the devolatilization step. When bulk polymerization is employed, polymerization is carried out until the amount of unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less, and then devolatilization is performed by known methods to remove volatile components such as the unreacted monomer. More specifically, conventional devolatilization equipment such as flash drums, twin-screw devolatars, thin-film evaporators, and extruders can be used, but devolatilization equipment with fewer retention areas is preferred. The temperature for the devolatilization treatment is usually around 190 to 280°C, and 190 to 260°C is more preferred from the viewpoint of suppressing the formation of six-membered ring acid anhydrides due to the proximity of unsaturated carboxylic acid monomers (e.g., methacrylic acid) and unsaturated carboxylic acid ester monomers (e.g., methyl methacrylate). Furthermore, the pressure used for devolatilization is typically around 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, and more preferably 0.13 to 2.0 kPa. Desirable devolatilization methods include, for example, removing volatile components by reducing pressure under heating, and removing them by passing the material through an extruder or the like designed for the purpose of removing volatile components.

[0052] <Silicone / acrylic composite rubber graft copolymer (B): Component (B)> In the flame-retardant styrene-based resin composition of this embodiment, the content of the silicone / acrylic composite rubber-based graft copolymer (B) is 3 to 25% by mass, more preferably 5 to 20% by mass, and even more preferably 8 to 15% by mass. If the content is less than 3% by mass, impact resistance cannot be obtained, and if it is more than 25% by mass, low dielectric properties and heat resistance are impaired.

[0053] The silicone / acrylic composite rubber graft copolymer (B) that can be used in this embodiment may be a composite rubber graft copolymer having a composite rubber containing a polyorganosiloxane and a polyalkyl (meth)acrylate, and a vinyl polymer composed of one or more vinyl monomer units, wherein the vinyl polymer is grafted onto the composite rubber. Furthermore, the silicone / acrylic composite rubber graft copolymer (B) is preferably in particulate form. The average particle size of the silicone / acrylic composite rubber graft copolymer (B) is not particularly limited, but is preferably 0.3 to 1.5 μm, and more preferably 0.5 to 1.2 μm. Setting the average particle size to 0.5 to 1.2 μm significantly improves impact resistance, as well as weather resistance and flame retardancy. In this invention, the average particle size of the silicone / acrylic composite rubber graft copolymer (B) is determined by measuring the primary particle size of the composite rubber graft copolymer dispersed in the styrene-based resin matrix using transmission electron microscopy (TEM). Specifically, it can be determined, for example, in the following manner. Ultrathin sections with a thickness of 100 nm, cut from the flame-retardant resin composition pellets of the present invention, were stained with osmium tetroxide vapor for 60 minutes, then with ruthenium tetroxide vapor for another 60 minutes, and then observed using TEM. Using the images obtained from TEM observation, the primary particle sizes of 30 composite rubber-based graft copolymers dispersed in the matrix were measured, and the number average was defined as the average particle size in the present invention.

[0054] The composite rubber content in the silicone / acrylic composite rubber graft copolymer (B) is preferably 70 to 90% by mass of 100% by mass of the composite rubber graft copolymer. A composite rubber content of 70% by mass or more tends to improve impact resistance, while a content of 90% by mass or less tends to improve color development and dispersibility while maintaining good impact resistance. Furthermore, the Si content of (B) in the composite rubber graft copolymer is preferably 1% by mass or more, and more preferably 2.5% by mass or more, from the viewpoint of further improving the impact resistance of the molded product, as detected by the ICP / AES method. There is no particular upper limit for the Si content, but it is preferably 10% by mass or less from the viewpoint of color development. The quantitative determination of Si by ICP / AES (Inductively Coupled Plasma / Atomic Emission Spectroscopy) was performed on a silicone / acrylic composite rubber graft copolymer after sulfuric acid decomposition and alkali melting treatment of the sample. The Si content was then determined using ICP / AES (JOBIN YVON Ultima 2C ICP emission spectrometer). The ICP / AES method is an analytical method that uses high-temperature plasma (inductively coupled plasma: ICP) obtained by applying a high voltage to a gas such as argon to create a plasma, and then generating Joule heat due to overcurrent within the plasma using a high-frequency fluctuating magnetic field. By introducing the sample into this high-temperature inductively coupled plasma, the sample is atomized and thermally excited, and the emission spectrum as it returns to its ground state allows for the identification and quantification of elements. The silicone / acrylic composite rubber graft copolymer (B) contains, in addition to a material having a structure in which monomers or monomer mixtures are grafted onto a composite rubber, an ungrafted (co)polymer. The grafting rate of the silicone / acrylic composite rubber graft copolymer (B) is not particularly limited, but 20 to 150%, and especially 25 to 100%, is preferred in order to obtain a resin composition that has excellent balance of impact resistance, flame retardancy, and gloss. Here, the grafting rate is calculated as follows: Grafting rate (%) = <Amount of vinyl copolymer grafted onto rubbery polymer particles (1)> / <Rubber content of silicone / acrylic composite rubber graft copolymer (B)> × 100.

[0055] In this embodiment, the composite rubber in the silicone / acrylic composite rubber graft copolymer (B) has a structure in which the polyorganosiloxane and the polyalkyl (meth)acrylate are intertwined in such a way that they cannot be separated from each other. As the polyorganosiloxane constituting the composite rubber, a polymer containing dimethylsiloxane units as constituent units is preferred. As the dimethylsiloxane constituting the polyorganosiloxane, examples include dimethylsiloxane-based cyclic compounds with three or more membered rings, with those having 3 to 7 membered rings being preferred. Specifically, examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. These can be used alone or in mixtures of two or more. Among these, octamethylcyclotetrasiloxane is preferred as the main component due to the ease of controlling the particle size distribution.

[0056] In this embodiment, the polyorganosiloxane is preferably one that contains a siloxane containing a vinyl polymerizable functional group as a component. Here, a siloxane containing a vinyl polymerizable functional group is one that contains a vinyl polymerizable functional group and can be bonded to dimethylsiloxane via a siloxane bond. Among siloxanes containing a vinyl polymerizable functional group, various alkoxysilane compounds containing a vinyl polymerizable functional group are preferred considering their reactivity with dimethylsiloxane. These siloxanes containing a vinyl polymerizable functional group can be used alone or as a mixture of two or more. Furthermore, the polyorganosiloxane of this embodiment may be crosslinked with a siloxane-based crosslinking agent. Examples of siloxane-based crosslinking agents include trifunctional or tetrafunctional silane-based crosslinking agents, such as trimethoxymethylsilane, triethoxyphenylsilane, and tetramethoxysilane. Examples include tetraethoxysilane and tetrabutoxysilane.

[0057] There are no particular limitations on the method for producing the polyorganosiloxane in this embodiment, and for example, the following method can be employed. First, a mixture containing dimethylsiloxane and, if necessary, a vinyl polymerizable functional group-containing siloxane, or a mixture further optionally containing a siloxane-based crosslinking agent, is emulsified with an emulsifier and water to prepare a latex. After the latex is atomized into fine particles, it is polymerized at high temperature using an acid catalyst, and then the acid is neutralized with an alkaline substance to obtain polyorganosiloxane latex. For the preparation of the latex, a method using a homogenizer is preferred because it tends to result in a narrower particle size distribution.

[0058] The emulsifier used in the above manufacturing method is not particularly limited as long as it can emulsify dimethylsiloxane, but anionic emulsifiers are preferred. Examples of anionic emulsifiers include sodium alkylbenzenesulfonate and sodium polyoxyethylene nonylphenyl ether sulfate, and among these, sodium alkylbenzenesulfonate and sodium laurylsulfonate are preferred.

[0059] Examples of acid catalysts used for polymerization of polyorganosiloxane in this embodiment include sulfonic acids such as aliphatic sulfonic acid, aliphatic-substituted benzenesulfonic acid, and aliphatic-substituted naphthalenesulfonic acid, as well as mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid. These acid catalysts can be used individually or in combination of two or more. Among these, mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid that do not have micelle-forming ability are preferred because they can narrow the particle size distribution of the polyorganosiloxane latex and further reduce defects in the appearance of molded articles caused by emulsifier components in the polyorganosiloxane latex.

[0060] In this embodiment, the polyalkyl (meth)acrylate constituting the composite rubber is a polymer containing alkyl (meth)acrylate units and polyfunctional alkyl (meth)acrylate units as constituent components. Examples of the alkyl (meth)acrylate include alkyl acrylates such as n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and alkyl methacrylates such as 2-ethylhexyl methacrylate and n-lauryl methacrylate, which can be used alone or in combination of two or more. Among these, n-butyl acrylate is particularly preferred considering impact resistance and weather resistance of the molded product.

[0061] Examples of the above-mentioned polyfunctional alkyl (meth)acrylates include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, triallyl cyanurate, etc., which can be used alone or in combination of two or more. There are no particular restrictions on the content of polyfunctional alkyl (meth)acrylate units, but it is preferably 0.1 to 2.0% by weight, and more preferably 0.3 to 1.0% by weight, of 100% by weight of polyalkyl (meth)acrylate. By setting the polyfunctional alkyl (meth)acrylate content to 0.1% by weight or more, the decrease in impact strength due to changes in the morphology of the composite rubber tends to be suppressed, and by setting the polyfunctional alkyl (meth)acrylate content to 2.0% by weight or less, the impact strength tends to be further improved.

[0062] To produce the composite rubber consisting of the polyorganosiloxane and polyalkyl (meth)acrylate described above, first, the alkyl (meth)acrylate component and the polyfunctional alkyl (meth)acrylate component are added to the latex of the polyorganosiloxane component and impregnated into the polyorganosiloxane. Then, a radical polymerization initiator such as a known peroxide, azo initiator, or redox polymerization initiator combining an oxidizing agent and a reducing agent is used, with redox polymerization initiators being preferred.

[0063] A composite rubber-based graft copolymer is obtained by radical polymerization of one or more vinyl monomers in the presence of the above-mentioned composite rubber to form graft portions made of vinyl polymers on the composite rubber. One specific manufacturing method is emulsion graft polymerization. In this emulsion graft polymerization method, a vinyl monomer is added to the latex of a composite rubber, and graft polymerization is carried out in one or multiple steps by radical polymerization to obtain a composite rubber graft copolymer latex. Next, this composite rubber graft copolymer latex is immersed in hot water in which a coagulant is dissolved, and the graft copolymer is separated by salting out and solidification, and recovered in powder form.

[0064] There are no particular limitations on the vinyl monomers mentioned above, but examples include aromatic alkenyl compounds such as styrene, α-methylstyrene, and vinyltoluene; methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, and 2-ethylhexyl methacrylate; acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate; and vinyl cyanide compounds such as acrylonitrile and methacrylonitrile.

[0065] Furthermore, the radical polymerization of the above-mentioned composite rubber and vinyl monomer can be carried out using the same radical polymerization initiators as those used in the production of the composite rubber consisting of the above-mentioned polyorganosiloxane and polyalkyl (meth)acrylate.

[0066] <Phosphonic acid ester compound or phosphinic acid compound (C): (C) component> In this embodiment, the phosphonic acid ester compound or phosphinic acid compound (C) has good moisture and heat resistance and therefore excellent weather resistance. When used in combination with a silicone / acrylic composite rubber graft copolymer (B) in which a vinyl polymer composed of one or more vinyl monomer units is grafted onto a composite rubber containing polyorganosiloxane and polyalkyl (meth)acrylate, it exhibits a high flame retardant synergistic effect. The phosphonic acid ester compound or phosphinic acid compound (C) includes phosphonic acid esters, phosphinic acid compounds, or phosphinate compounds. The content of the phosphonic acid ester compound or phosphinic acid compound (C) in the flame-retardant styrene resin composition of this embodiment is 1 to 30% by mass, preferably 2 to 25% by mass, and more preferably 3 to 20% by mass. If the content is 1% by mass or more, sufficient flame retardancy can be obtained. Furthermore, if the content is 30% by mass or less, a flame-retardant styrene resin composition with excellent impact resistance can be obtained.

[0067] <<Phosphonic acid ester compounds>> Examples of phosphonic acid ester compounds in this embodiment include those represented by the following chemical formula (1). [Chemical formula] (In the above chemical formula (1), R 6 ~R 10 are each independently a hydrogen atom or a monovalent hydrocarbon group which may have a substituent, and R 6 ~R 10 may be the same or different from each other.) In the present specification, as the monovalent hydrocarbon group, it may be either linear (either straight-chain or branched-chain) or cyclic (any of monocyclic, condensed polycyclic, bridged cyclic and spiro cyclic), and examples thereof include a cyclic hydrocarbon group having a side chain. Further, the hydrocarbon group may be either saturated or unsaturated. Examples of the monovalent hydrocarbon group include an alkyl group, a cycloalkyl group, an allyl group, an aryl group, an alkylaryl group, an arylalkyl group, and the like. <>

[0068] Specific examples of the phosphonate ester compound represented by the above chemical formula (1) include compounds represented by the following formulas (1-1) to (1-8). [Chemical formula] [[ID=2 --]]

[0069] [[ID=3 —]] Further, as the phosphonate ester compound, a compound represented by the following general formula (2) can also be used. [Chemical formula] (In the above general formula (2), X 1 , X 2 are each independently an aromatic substituted alkyl group represented by the following formula (3).) [Chemical formula] (In the above general formula (3), La is a branched or straight-chain aliphatic hydrocarbon group having 1 to 5 carbon atoms, Lr is a phenyl group, a naphthyl group or an anthryl group which may have a substituent, and n is an integer of 1 to 3. Further, * in the general formula (3) represents a bond with a phosphorus atom.)

[0070] Examples of aliphatic hydrocarbon groups of La in the above general formula (3) include alkanediyl groups, alkanetriyl groups, and alkanetetrayl groups. Specifically, examples include alkylene groups with 1 to 5 carbon atoms, such as methylene, ethylene, trimethylene, isopropyldiyl, butylene, and pentylene groups. Also, examples include alkanetriyl groups with 1 to 5 carbon atoms, such as methanetriyl, ethanetriyl, propanetriyl, butanetriyl, and pentanetriyl groups. Furthermore, examples include alkanetetrayl groups with 1 to 5 carbon atoms, such as methanetetrayl, ethanetetrayl, propanetetrayl, butanetetrayl, and pentanetetrayl groups.

[0071] In the above general formula (3), Lr is a phenyl group, naphthyl group, or anthryl group, which may be unsubstituted or substituted. Examples of substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, or propyl groups, and halogen atoms, such as fluorine, chlorine, or bromine atoms. In addition, in the above general formula (3), Lr can be bonded to any carbon atom in La.

[0072] In this embodiment, a particularly preferred form of the phosphonic acid ester compound represented by general formula (2) is the compound represented by the following formula (4). [ka]

[0073] In the above general formula (4), R 12 and R 15 These are each a phenyl group, naphthyl group, or anthryl group, which may be the same or different, and which may have substituents. Examples of substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, and propyl groups, and halogen atoms, such as fluorine, chlorine, and bromine atoms.

[0074] In the above general formula (4), R 11 , R13 , R 14 , R 16 Each of these may be independent of and identical or different, and may be a hydrogen atom, a branched or linear alkyl group having 1 to 4 carbon atoms, or a substitution. It is a group selected from a phenyl group, a naphthyl group, or anthryl group, which may have a group. Examples of alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, and t-butyl groups. Examples of substituents on phenyl, naphthyl, or anthryl groups include alkyl groups having 1 to 5 carbon atoms such as methyl, ethyl, and propyl groups, and halogen atoms such as fluorine, chlorine, and bromine atoms.

[0075] In this embodiment, another preferred form of the phosphonic acid ester compound represented by general formula (2) is the compound represented by the following general formula (5). [ka]

[0076] In the above general formula (5), R 21 , R 22 These are each an independent, identical or distinct phenyl group, naphthyl group, or anthryl group, which may have substituents on their aromatic rings, with the phenyl group being preferred. In the above general formula (5), R 21 and R 22 The phenyl group, naphthyl group, or anthryl group may have a hydrogen atom substituted on its aromatic ring. Examples of substituents include methyl, ethyl, propyl, butyl, or an aryl group having 6 to 14 carbon atoms, with the bonding group of the aromatic ring being an oxygen atom, a sulfur atom, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

[0077] In this embodiment, other preferred forms of the phosphonic acid ester compound represented by general formula (2) include, in particular, the compound represented by the following general formula (6). [ka]

[0078] <<Phosphinic acid compounds>> The phosphinic acid compound according to this embodiment is of general formula (7) [ka] [In the above general formula (7), R 1a and R 1b Each of these is independently identical or distinct, representing a hydrogen atom, a halogen atom, or a lower alkyl group, and R 1c x represents a hydrogen atom, halogen atom, hydroxyl group, lower alkoxyl group, or lower alkyl group, and x, y, and z each independently represent an integer from 1 to 4. Compounds represented by ] and / or general formula (8) [ka] [In the above general formula (8), R 2a and R 2b Each of these is independently identical or different, representing a hydrogen atom, a halogen atom, or a lower alkyl group, and R 2c Compounds represented by [where x and y are independently the same or different and represent a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkoxyl group, or a lower alkyl group, and x or y are independently integers from 1 to 4, and z is an integer from 1 to 5] are preferred. From the viewpoint of excellent color tone and flame retardancy, compounds of general formula (7) are more preferred, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is particularly preferred.

[0079] Furthermore, in general formulas (7) or (8), "lower alkoxy group, lower alkyl" refers to a linear, branched, or cyclic alkoxy group or alkyl group having 1 to 5 carbon atoms.

[0080] In this embodiment, examples of phosphinic acid compounds include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or 10-benzyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. Examples of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide include HCA from Sanko Co., Ltd. Also, 10-benzyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide For example, BCA from Sanko Co., Ltd. can be used as an additive.

[0081] -Phosphinate compounds- In this embodiment, the phosphinic acid compound includes phosphinate compounds. The phosphinate compound in this embodiment is represented by the following general formula (i) and preferably contains at least one phosphinate selected from phosphinates and diphosphinates, and more preferably 70% by mass or more of the total phosphinate compound (100% by mass). The following general formula (i): [ka] [In the above equation (i), R i1 and R i2 Each of these is independently either unsubstituted or has one or more hydrogen atoms substituted R i3 A linear or branched alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 6 to 14 carbon atoms, which may be substituted by: The substituent R i3 This is expressed by the following formula (ii): [ka] In the above formula (ii), R ii1 Each of these is independently a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, and * represents a bond with another atom. M iis at least one selected from the group consisting of calcium ions, magnesium ions, aluminum ions, zinc ions, bismuth ions, manganese ions, sodium ions, potassium ions, and protonated nitrogen bases, p + is M i It represents the ion valency, and is a positive integer from 1 to 3, m i1 n is a positive integer between 1 and 3. - |p| represents a negative integer of -1, -2, or -3, and r is a positive integer of 1 to 3. + ×r|=|n - xm i1 | is also R i1 and R ii1 If there are multiple instances of each, each R i1 and R ii1 They may be the same or different. Therefore, the phosphinate compound in this embodiment may contain known flame retardants other than phosphinates represented by general formula (i) in an amount of 30% by mass or less relative to the total amount of the phosphinate compound (100% by mass). In the above formula (i), M i The ion value of "p + The absolute value of the product of " and "r" is "n - " and "m i1 It is equal to the absolute value of the product of and . In (i) above, p + 1 or 2 is preferred. i1 1 or 2 is preferred. - For -1 or -2, r is preferably 1 or 2.

[0082] In this embodiment, preferred phosphinate compounds are represented by the following general formula (iii). [ka] [In the above formula (iii), R 11 and R 12 Each is independently a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, M 1is at least one selected from the group consisting of calcium ions, magnesium ions, aluminum ions, zinc ions, bismuth ions, manganese ions, sodium ions, potassium ions, and protonated nitrogen bases, a + is M 1 It represents the ion valency, and is an integer from 1 to 3, m 1 a is an integer between 1 and 3, and a = m 1 That is. R 11 and R 12 If there are multiple instances of each, each R 11 and R 12 They may be the same or different.

[0083] In this embodiment, preferred diphosphinates are those represented by the following general formula (iv). [ka] [In the above formula (iv), R 21 and R 22 Each is independently a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, L 23 This is a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 6 to 14 carbon atoms, or an arylalkylene group having 6 to 14 carbon atoms, M 2 b is at least one selected from the group consisting of calcium ions, magnesium ions, aluminum ions, zinc ions, bismuth ions, manganese ions, sodium ions, potassium ions, and protonated nitrogen bases, + is M 2 It represents the ion valency, and is an integer from 1 to 3, m 2 b is an integer between 1 and 3, q ​​is an integer of 1 or 2, and b × q = 2m 2 That is. R 21 and R 12 If there are multiple instances of each, each R 21 and R 22They may be the same or different. At least one is selected from the group consisting of ].

[0084] In the above formulas (i), (ii), (iii), and (iv), examples of linear or branched alkyl groups having 1 to 6 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl, butyl, amyl, or hexyl groups, and branched alkyl groups such as isopropyl, isobutyl, s-butyl, t-butyl, isoamyl, or t-amyl groups. In the above formulas (i), (ii), (iii), and (iv), the aryl group having 6 to 10 carbon atoms may have a monocyclic or fused ring structure. Examples include the phenyl group or the naphthyl group. In formula (iv) above, a linear or branched alkylene group having 1 to 10 carbon atoms can be a group obtained by removing one hydrogen atom from the linear or branched alkyl group having 1 to 6 carbon atoms. In the above formula (iv), the arylene group having 6 to 10 carbon atoms is a group obtained by removing one hydrogen atom from the above aryl group having 6 to 10 carbon atoms. In formula (i) above, the aralkyl group having 6 to 14 carbon atoms can be a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group, a methylphenyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a methylnaphthyl group, an ethylnaphthyl group, or a tert-butylnaphthyl group. In formula (iv) above, examples of alkylarylene groups having 6 to 14 carbon atoms include methylphenylene group, ethylphenylene group, tert-butylphenylene group, methylnaphthylene group, ethylnaphthylene group, and tert-butylnaphthylene group. In the above formula (iv), examples of arylalkylene groups having 6 to 14 carbon atoms include phenylmethylene, phenylethylene, phenylpropylene, and phenylbutylene groups. In the above equation (iii), R 11 and R 12Each of these is preferably independently a linear alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. In the above formula (iii), M 1 Calcium, magnesium, aluminum, or zinc are preferred. Also, a is M 1 This represents the ionic charge, which is 2 or 3. In the above equation (iv), R 21 and R 22 Each of these is preferably independently a linear alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. In the above equation (iv), L 23 Each of these is preferably independently a linear alkylene group having 1 to 6 carbon atoms or an arylene group having 6 to 10 carbon atoms. In the above equation (iv), M 2 Calcium, magnesium, aluminum, or zinc are preferred. Also, b is M 2 This represents the ionic charge, which is 2 or 3. Phosphinate compounds have excellent electrical properties, making them suitable for flame-retardant materials requiring insulation. They also have excellent hydrolytic properties, making them suitable for use in high-temperature and high-humidity environments, and they are highly recyclable.

[0085] The phosphinates used in this embodiment are primarily monomeric compounds, produced in aqueous solution using phosphinic acid and metal carbonates, metal hydroxides, or metal oxides. However, depending on the reaction conditions and environment, polymeric phosphinates with a condensation degree of 1 to 3 may also be included.

[0086] Such phosphinates are not particularly limited, but include, for example, calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methanedi(methylphosphinate), magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate) Examples include aluminum, zinc methanedi(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, and zinc diphenylphosphinate, as well as calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, aluminum ethylbutylphosphinate, and dibouti It is preferable that the material is aluminum diethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, or zinc diethylphosphinate, and more preferably aluminum diethylphosphinate. Examples of commercially available phosphinate compounds (b) include, but are not limited to, Exolit® OP1230, OP1240, OP1311, OP1312, OP930, and OP935 manufactured by Clariant Japan.

[0087] In this embodiment, the phosphonic acid ester compound or phosphinic acid compound (C) (including phosphinate compound) is preferably granular. In particular, when the phosphinate compound is granular, the average particle size of the phosphinate compound is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 20 μm or less, from the viewpoint of improving the mechanical strength and appearance of the molded article obtained by molding the flame-retardant styrene resin composition of this embodiment, and it is preferable to use a powder of the phosphinate compound that has been ground to this particle size. Preferably, it is more than 0.5 μm and 20 μm, and more preferably more than 1 μm and 20 μm or less. Using a powder with a preferred particle size is particularly preferable because it not only exhibits high flame retardancy but also significantly increases impact strength. When a granular phosphinate compound is used as the phosphinate compound in this embodiment, the average particle size of the granular phosphinate compound is measured based on the volume-based particle size measured using a laser diffraction / scattering particle size distribution analyzer. Furthermore, the value is measured using a 3% isopropanol aqueous solution as the dispersion medium for the phosphinate compound. Specifically, using a laser diffraction / scattering particle size distribution analyzer LA-910 (manufactured by Horiba, Ltd.), a blank measurement is performed with a 3% isopropanol aqueous solution as the dispersion medium, and then the sample is added to achieve a specified transmittance (95% to 70%) and measured. The dispersion of the sample in the dispersion medium is performed by irradiating it with ultrasound for 1 minute.

[0088] The flame-retardant styrene resin composition of this embodiment may further contain 0.05 to 3 parts by mass of one or more selected from the group consisting of hindered amine compounds (D) and ultraviolet absorbers (E) per 100 parts by weight of the total amount of components (A), (B), and (C). <Hindered amine compounds (D): Component (D)> The flame-retardant styrene resin composition of this embodiment may contain a hindered amine compound (D). The content of the hindered amine compound (D) is 0.05 to 3 parts by weight, preferably 0.1 to 2.5 parts by weight, and more preferably 0.2 to 2.0 parts by weight, per 100 parts by weight of the total amount of components (A), (B), and (C). High weather resistance can be obtained if the content is 0.1% by mass or more, or 3.0% by mass or less. The hindered amine compound (D) is preferably a NOR (alkoxyimino group) type hindered amine compound or a hindered amine light stabilizer. In particular, the NOR (alkoxyimino group) type hindered amine compound has a synergistic effect with component (C) in terms of flame retardancy, resulting in high flame retardancy.

[0089] The alkoxyimino group in the aforementioned NOR (alkoxyimino group) type hindered amine compounds is an N-alkoxyl group (>N-OR) structure, as opposed to the NH type where the imino group (>NH) portion of the piperidine ring remains NH, or the N-methyl type where H is replaced by a methyl group. The N-alkoxyl group readily captures alkyl peroxy radicals (R'O2·) and becomes a radical, exhibiting a flame retardant effect. On the other hand, in the case of N-methyl type hindered amine compounds or NH type hindered amine compounds, there is a risk of reduced flame retardancy.

[0090] The above alkoxyl group (-OR) is not limited to an alkoxyl group in which oxygen is bonded to an alkyl group, and R includes groups other than alkyl groups, such as cycloalkyl groups, aralkyl groups, and aryl groups.

[0091] Specific examples of these alkoxy groups include methoxy, propoxy, cyclohexyloxy, and octyloxy groups. In particular, from the viewpoint of suppressing the bleed-out of component (B) or component (C) from molded articles (e.g., sheets and films) formed from the composition of this embodiment, propoxy, cyclohexyloxy, or octyloxy groups are preferred as they increase the molecular weight of the NOR-type hindered amine compound.

[0092] The NOR-type hindered amine compounds used in this embodiment are not particularly limited as long as they have an N-alkoxyl group (>N-OR) structure. Specific examples include, for instance, NOR-type hindered amine compounds described in Japanese Patent Publication No. 2002-507238, International Publication No. 2005 / 082852, International Publication No. 2008 / 003605, etc., which are preferred examples.

[0093] Furthermore, among NOR-type hindered amine compounds, high-molecular-weight types are particularly preferred. High-molecular-weight types are generally oligomeric or polymeric compounds. High-molecular-weight types reduce mold deposits during molding and offer superior plating properties.

[0094] The above-mentioned oligomeric or polymeric NOR-type hindered amine compound preferably has 2 to 100 repeating units, and more preferably 5 to 80.

[0095] Specific examples of NOR-type hindered amine compounds include the following compounds: 1-cyclohexyloxy-2,2,6,6-tetramethyl-4-octadecylaminopiperidine; 2,2,6,6-tetramethyl-4-piperidyl)sebacate; 2,4-bis[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl)butylamino]-6-(2-hydroxyethylamino)-s-triazine; bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl)adipate; 4, An oligomeric compound formed by the condensation of 4'-hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine) and 2,4-dichloro-6-[(1-octyloxy-2,2,6,6-tetramethylpiperidine-4-yl)butylamino]-s-triazine, which is terminally capped with 2-chloro-4,6-bis(dibutylamino)-s-triazine; 4,4'-hexamethylenebis(amino-2,2,6,6-tetramethylpiperidine) and 2-chloro-4,6-bis(dibutylamino)-s-triazine An oligomeric compound that is a condensation product with 2,4-dichloro-6-[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl)butylamino]-s-triazine; 2,4-bis[(1-cyclohexyloxy-2,2,6,6-piperidine-4-yl)-6-chloro-s-triazine; peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine, 2,4,6-trichloro-s-triazine, cyclohexane, and N,N'-ethane-1,2-diylbis(1,3-propanediamine) Reaction products with (N,N',N'''-Tris{2,4-bis[(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidine-4-yl)n-butylamino]-s-triazine-6-yl}-3,3'-ethylenediiminodipropylamine); bis(1-undecanoxy-2,2,6,6-tetramethylpiperidine-4-yl) carbonate; 1-undecyloxy-2,2,6,6-tetramethylpiperidine-4-one; bis(1-stearyloxy-2,2,6,6-tetramethylpiperidine-4-yl) carbonate.

[0096] Examples of commercially available NOR-type hindered amine compounds include FlamestabNOR116FF, TINUVIN NOR371, TINUVIN XT850FF, TINUVIN XT855FF, and TINUVIN PA123 from BASF, and LA-77Y, LA-81, and FP-T80 from ADEKA Corporation.

[0097] In this embodiment, the above-described NOR-type hindered amine compound (B) may be used alone or in combination of two or more.

[0098] The hindered amine light stabilizers used as hindered amine compounds (D) in this embodiment include, for example, 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis(2, 2,6,6-Tetramethyl-4-piperidyl)-1,2,3,4-Butanetetracarboxylate, Tetrakis(1,2,2,6,6-Pentamethyl-4-piperidyl)-1,2,3,4-Butanetetracarboxylate, Bis(2,2,6,6-Tetramethyl-4-piperidyl)·di(tridecyl)-1,2,3,4-Butanetetracarboxylate, Bis(1,2,2,6,6-Pentamethyl-4-piperidyl)·di(tridecyl)-1,2,3,4-Butanetetracarboxylate, Bis(1,2,2,4,4-Pentamethyl-4-piperidyl)-2 -Butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-tert-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[ 2,4-Bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]-1,5,8-12-tetraazadodecane, 1,6,11-Tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane, 1,Examples of hindered amine compounds include 6,11-tris[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazine-6-yl]aminoundecane. These may be used individually or in combination of two or more. In this embodiment, the hindered amine compound (D) is preferably one or more selected from the group consisting of NOR (alkoxyimino group) type hindered amine compounds and hindered amine light stabilizers. Therefore, the hindered amine compound (D) may be a mixture of NOR (alkoxyimino group) type hindered amine compounds, a mixture of hindered amine light stabilizers, or a mixture of NOR (alkoxyimino group) type hindered amine compounds and hindered amine light stabilizers.

[0099] <UV absorber (E): (E) component> In this embodiment, the content of the ultraviolet absorber (E) is 0.05 to 3 parts by weight, preferably 0.1 to 2.5 parts by weight, and more preferably 0.2 to 2.0 parts by weight, per 100 parts by weight of the total amount of components (A), (B), and (C). A highly weather-resistant flame-retardant styrene resin composition can be obtained if the content is 0.1% by weight or more, or 3.0% by weight or less.

[0100] Examples of the ultraviolet absorber (E) in this embodiment include organic ultraviolet absorbers such as benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, triazine compounds, oxanilide compounds, and malonic acid ester compounds. Among these, organic ultraviolet absorbers are preferred, benzotriazole compounds, benzophenone compounds, and triazine compounds are more preferred, benzophenone compounds and triazine compounds are even more preferred, and benzophenone compounds are particularly preferred. By selecting an organic ultraviolet absorber, the transparency and mechanical properties of the styrene-based resin composition of the present invention are improved.

[0101] Specific examples of the above benzotriazole compounds include, for example, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butyl-phenyl)-benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole), and 2-(2'-hydroxy-3',5'-di-ter Examples include t-amyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2N-benzotriazole-2-yl)phenol], among which 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2N-benzotriazole-2-yl)phenol] are preferred, and 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole is particularly preferred.

[0102] Examples of commercially available benzotriazole compounds include "Seesorb 701," "Seesorb 705," "Seesorb 703," "Seesorb 702," "Seesorb 704," and "Seesorb 709" from Cipro Chemical Co., Ltd., "Biosorb 520," "Biosorb 582," "Biosorb 580," and "Biosorb 583" from Kyodo Pharmaceutical Co., Ltd., "Chemisorb 71," "Chemisorb 72," and "Chemisorb 79" from Chemipro Chemical Co., Ltd., "Ciasorb UV5411" from Cytec Industries, Ltd., "LA-32," "LA-38," "LA-36," "LA-34," and "LA-31" from ADEKA Corporation, and "Chinubin P," "Chinubin 234," "Chinubin 326," "Chinubin 327," and "Chinubin 328" from BASF Corporation.

[0103] Specific examples of the above-mentioned benzophenone compounds include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-n-dodecyloxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.

[0104] Examples of commercially available benzophenone compounds include "Seesorb 100", "Seesorb 101", "Seesorb 101S", "Seesorb 102", and "Seesorb 103" from Cipro Chemical Co., Ltd., "Biosorb 100", "Biosorb 110", and "Biosorb 130" from Kyodo Pharmaceutical Co., Ltd., "Chemisorb 10", "Chemisorb 11", "Chemisorb 11S", "Chemisorb 12", "Chemisorb 13", and "Chemisorb 111" from Chemipro Chemical Co., Ltd., "Ubinal 3049" and "Ubinal 3050" from BASF, "Ciasorb UV9", "Ciasorb UV284", "Ciasorb UV531", and "Ciasorb UV24" from Scitec Industries, Ltd., and "ADEKA Stab 1413" and "ADEKA Stab LA-51" from ADEKA Corporation.

[0105] Examples of the above triazine compounds include, for example, compounds having a 1,3,5-triazine skeleton. Specifically, such triazine compounds include, for example, those manufactured by ADEKA Corporation. Examples include the "LA-46," "LA-F70," and BASF's "Chinubin 1577ED," "Chinubin 1600," "Chinubin 400," "Chinubin 405," "Chinubin 460," "Chinubin 477-DW," and "Chinubin 479."

[0106] Specific examples of the salicylate compounds mentioned above include phenyl salicylate and 4-tert-butylphenyl salicylate. Commercially available products of such salicylate compounds include, for example, "Seesorb 201" and "Seesorb 202" from Cipro Chemical Co., Ltd., and "Chemisorb 21" and "Chemisorb 22" from Chemipro Chemical Co., Ltd.

[0107] Specific examples of the above cyanoacrylate compounds include, for example, ethyl-2-cyano-3,3-diphenylacrylate and 2-ethylhexyl-2-cyano-3,3-diphenylacrylate. Commercially available products of such cyanoacrylate compounds include, for example, "Seesorb 501" manufactured by Cipro Chemical Co., Ltd., "Biosorb 910" manufactured by Kyodo Pharmaceutical Co., Ltd., "Ubisorator 300" manufactured by Daiichi Chemical Co., Ltd., and "Ubinal 3030", "Ubinal 3035", and "Ubinal 3039" manufactured by BASF.

[0108] Specific examples of the above-mentioned oxalinilide compounds include, for example, 2-ethoxy-2'-ethyloxalinilide acid bisalindide, and commercially available products of such oxalinilide compounds include, for example, Clariant's "Hostavin VSU".

[0109] As the above malonic acid ester compound, 2-(alkylidene)malonic acid esters are preferred, and 2-(1-arylalkylidene)malonic acid esters are more preferred. Examples of commercially available malonic acid ester compounds include Clariant's "Hostavin PR-25" and "Hostavin B-CAP".

[0110] <Optional addition ingredients> The flame-retardant styrene resin composition of this embodiment and the molded article containing the flame-retardant styrene resin composition may contain, in addition to the above components (A) to (E), any conventionally known additives, processing aids, and other optional additives as needed, provided that the effects of the present invention are not impaired. Examples of such additives and processing aids include antioxidants, flame retardants, lubricants, antistatic agents, and fillers.

[0111] Examples of the above-mentioned antioxidants include phenolic compounds, phosphorus compounds, and thioether compounds.

[0112] Examples of the above phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, distearyl(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, 1,6-hexamethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 4,4'-thiobis(6-tert-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 2, 2'-Ethylenedenbis(4,6-di-tert-butylphenol), 2,2'-Ethylenedenbis(4-sec-butyl-6-tert-butylphenol), 1,1,3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-Tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate, 1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 2-tert-butyl-4-methyl-6-(2-acryloyloxy-3- tert-butyl-5-methylbenzyl)phenol, stearyl [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate methyl]methane, thiodiethylene glycol bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylene bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyric acid]glycol ester, bis Examples include 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, and triethylene glycol bis[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]. These may be used individually or in combination of two or more.

[0113] Examples of the phosphorus-based antioxidants mentioned above include tris(2,4-di-tert-butylphenyl) phosphite, trisnonylphenyl phosphite, tris[2-tert-butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl] phosphite, tridecyl phosphite, octyldiphenyl phosphite, di(decyl)monophenyl phosphite, di(tridecyl)pentaerythritol diphosphite, and di(nonylphenyl)pentaerythritol Litol diphosphite, bis(2,4-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetra(tridecyl)isopropylidene diphenol diphosphite, tetra(tridecyl)-4,4'-n- Butylidenebis(2-tert-butyl-5-methylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite, tetrakis(2,4-di-tert-butylphenyl) biphenylenediphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-tert-butylphenyl)-2-ethylhexylphosphate Examples include 2,2'-methylenebis(4,6-tert-butylphenyl)-octadecyl phosphite, 2,2'-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetrakis-tert-butyldibenzo[d,f][1,3,2]dioxaphosphine-6-yl)oxy]ethyl)amine, and phosphites of 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-tert-butylphenol. These may be used individually or in combination of two or more.

[0114] Examples of the thioether-based antioxidants mentioned above include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, as well as pentaerythritol tetra(β-alkylmercaptopropionate esters). These may be used individually or in combination of two or more.

[0115] As the above lubricant, fatty acid amides, fatty acid esters, fatty acids, fatty acid metal salts, etc., can be used.

[0116] Examples of the above aliphatic amide lubricants include stearic acid amide, oleic acid amide, and erucic acid. Examples include amides, beheninamides, ethylenebisstearate amides, ethylenebisoleamides, ethylenebiserucamides, and ethylenebislaurylamides. These may be used individually or in combination of two or more.

[0117] The above aliphatic ester lubricants include methyl laurate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl erucate, methyl behenate, butyl laurate, butyl stearate, isopropyl myristate, isopropyl palmitate, octyl palmitate, octyl coconut fatty acid ester, octyl stearate, octyl beef tallow fatty acid ester, lauryl laurate, stearyl stearate, behenyl behenate, cetyl myristate, esters of montanic acid and ethylene glycol, esters of montanic acid and glycerin, and mon Examples include esters of tanic acid and butylene glycol, esters of montanic acid and trimethylolethane, esters of montanic acid and trimethylolpropane, esters of montanic acid and pentaerythritol, glycerin monostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, sorbitan trioleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate. These may be used individually or in combination of two or more.

[0118] Among the fatty acid-based lubricants mentioned above, saturated fatty acids specifically include lauric acid (dodecanoic acid), isodecanoic acid, tridecylic acid, myristic acid (tetradecanoic acid), pentadecylic acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), isostearic acid, tubercurostearic acid (nonadecanoic acid), 2-hydroxystearic acid, arachidic acid (eicosanoic acid), behenic acid (docosanoic acid), lignoceric acid (tetradocosanoic acid), cerotic acid (hexadocosanoic acid), montanic acid (octadocosanoic acid), melissic acid, etc., with lauric acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, and montanic acid being particularly noteworthy.

[0119] Among the fatty acid-based lubricants mentioned above, specific examples of unsaturated fatty acids include myristoleic acid (tetradecenoic acid), palmitoleic acid (hexadecenoic acid), oleic acid (cis-9-octadecenoic acid), elaidic acid (trans-9-octadecenoic acid), ricinoleic acid (octadecadienoic acid), vaccenic acid (cis-11-octadecenoic acid), linoleic acid (octadecadienoic acid), linolenic acid (9,11,13-octadecatrienoic acid), elestearic acid (9,11,13-octadecatrienoic acid), gadoleic acid (eicosanic acid), erucic acid (docosanoic acid), nervonic acid (tetradocosanoic acid), etc. These may be used individually or in combination of two or more.

[0120] Examples of the above-mentioned fatty acid metal salt lubricants include lithium salts, calcium salts, magnesium salts, and aluminum salts of the fatty acids in the above-mentioned fatty acid lubricants. These may be used individually or in combination of two or more.

[0121] As the above-mentioned antistatic agents, cationic, anionic, nonionic, amphoteric, and fatty acid partial esters such as glycerin fatty acid monoesters can be used. Specifically, alkyltrimethylammonium salts, dialkyldimethylammonium salts, benzalkonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methylammonium mesosulfate, (3-laurylamidopropyl)trimethylammonium methylsulfate, stearamidopropyldimethyl-2-hydroxyethylammonium nitrate, stearamidopropyldimethyl-2-hydroxy Examples include ethylammonium phosphate, cationic polymers, alkyl sulfonates, alkylbenzene sulfonates, sodium alkyldiphenyl ether disulfonate, alkyl nitrate salts, alkyl phosphate salts, alkyl phosphate amine salts, monoglyceride stearate, pentaerythritol fatty acid esters, sorbitan monopalmitate, sorbitan monostearate, diglycerin fatty acid esters, alkyldiethanolamine, alkyldiethanolamine fatty acid monoesters, alkyldiethanolamide, polyoxyethylene dodecyl ether, polyoxyethylene alkylphenyl ether, polyethylene glycol monolaurate, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyether block copolymer, cetyl betaine, hydroxyethylimidazoline sulfate, and the like. These may be used individually or in combination of two or more.

[0122] Examples of fillers that can be used include talc, calcium carbonate, barium sulfate, carbon fiber, mica, wollastonite, and whiskers.

[0123] In this embodiment, the styrene-based resin composition and the molded article containing the styrene-based resin composition may contain the above-mentioned additives and processing aids, as well as other optional additives such as blocking inhibitors, colorants, blooming inhibitors, surface treatment agents, antibacterial agents, and eye discharge inhibitors (eye discharge inhibitors such as silicone oil described in Japanese Patent Application Publication No. 2009-120717, monoamide compounds of higher aliphatic carboxylic acids, and monoester compounds obtained by reacting higher aliphatic carboxylic acids with monovalent to trivalent alcohol compounds). The total content of optional additives such as additives and processing aids may be 0.05 to 5% by mass of the styrene-based resin composition (100% by mass).

[0124] The flame-retardant styrene resin composition of this embodiment may consist substantially only of components (A) to (E) and optional additives. Alternatively, it may consist only of components (A) to (E), or only of components (A) to (E) and optional additives.

[0125] "Substantially consisting only of components (A) to (E) and optional additives" means that 95 to 100% (preferably 98 to 100% by mass) of the flame-retardant styrene resin composition is either components (A) to (E), or components (A) to (E) and optional additives. Furthermore, the flame-retardant styrene resin composition of this embodiment may contain unavoidable impurities in addition to components (A) to (E) and optional additives, as long as the effects of the present invention are not impaired.

[0126] <Method for producing flame-retardant styrene-based resin composition> The flame-retardant styrene resin composition of this embodiment can be manufactured by melt-kneading each component in any manner. For example, methods include using a high-speed agitator such as a Henschel mixer, a batch-type kneader such as a Banbury mixer, a single-screw or twin-screw continuous kneader, a roll mixer, etc., either individually or in combination. The heating temperature during kneading is usually selected in the range of 180 to 260°C.

[0127] [Physical properties of flame-retardant styrene-based resin compositions] <Flame-retardant> The flame retardancy of the flame-retardant styrene resin composition of this embodiment is preferably within the standard in the UL94 vertical combustion test (UL94-V test), i.e., it is in the flame retardancy class of V-0 to V-2. In this disclosure, flame retardancy can be evaluated by the method described in the [Examples] section below.

[0128] <Charpy impact strength (with notch)> The Charpy impact strength (with notch) of the flame-retardant styrene resin composition of this embodiment is 4 kJ / m². 2 It is preferable that the value be greater than or equal to 6 kJ / m³, and more preferably 6 kJ / m³. 2 The above is preferable, and more preferably 8 kJ / m 2 That's all. The Charpy impact strength (with notch) is 4 kJ / m 2As a result, the mechanical strength of the resin composition can be ensured. The Charpy impact strength (without notches) can be measured in accordance with ISO 179.

[0129] <Weather resistance> The weather resistance of the flame-retardant styrene resin composition of this embodiment preferably has a Charpy impact strength (with notch) retention rate of 50% or more of the initial Charpy impact strength (with notch), and more preferably 70% or more. If the retention rate is less than 50%, the flame-retardant styrene resin composition may not be usable for outdoor or lighting applications due to a decrease in product strength, or it may discolor indoors, impairing its design and recyclability. The weather resistance test involves measuring the Charpy impact strength (with notches) of a Charpy impact strength test specimen after 500 hours using a xenon lamp weathermeter. This is done in a cycle of maintaining the black panel temperature at 63°C and spraying water for 18 minutes out of every 120 minutes. The retention rate is then calculated relative to the initial value.

[0130] <Dielectric constant and dielectric loss tangent> The dielectric constant of the flame-retardant styrene-based resin composition of this embodiment is preferably 3 or less, and more preferably 2.5 or less. Furthermore, the dielectric loss tangent is 0.01 or less, and more preferably 0.005 or less. If the dielectric constant is greater than 3 and the dielectric loss tangent is greater than 0.01, dielectric loss increases at high frequencies of 1 GHz or higher, leading to product defects. In this disclosure, the dielectric constant and dielectric loss tangent are values ​​measured at 10 GHz in accordance with IEC 62810 (cavity resonator perturbation method).

[0131] [Molded products] The styrene-based resin composition of this embodiment can be used to produce molded articles by the above-mentioned melt-kneading molding machine, or by using the resulting styrene-based resin composition pellets as a raw material, through injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, and the like.

[0132] Molded articles containing the styrene-based resin composition of this embodiment are preferably suitable for use in injection-molded articles (including injection-compressed articles), office automation equipment such as photocopiers, fax machines, televisions, radios, tape recorders, video decks, personal computers, printers, telephones, information terminals, lighting, refrigerators, microwave ovens, and other household electrical appliances, housings and various parts for electrical and electronic equipment, foamed insulation materials, insulating films, and the like. [Examples]

[0133] The embodiments of the present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited in any way by these embodiments.

[0134] "Measurement and Evaluation Methods" The physical properties of the resin compositions obtained in each example and comparative example were measured and evaluated based on the following methods. (1) Flame retardant Using test specimen (a) (size: 127 mm × 12.7 mm, thickness: 1.5 mm) prepared by the method described below, flame retardancy was evaluated in accordance with the UL94 vertical combustion test (UL94-V test) using a 50W test flame. The above test specimen (a) was exposed to a gas burner flame, and the degree of combustion was evaluated. The flame retardancy rating indicates the flame retardancy class classified by the UL94-V test. Five tests were conducted on each test specimen for evaluation. The general classification method is as follows: V-0: Total burning time of 5 sticks is 50 seconds or less, maximum burning time is 10 seconds or less, no drip cotton ignition. V-1: Total burning time of 5 sticks is 250 seconds or less, maximum burning time is 30 seconds or less, no drip cotton ignition. V-2: Total burning time of 5 sticks is 250 seconds or less, maximum burning time is 30 seconds or less, with drip cotton ignition. Not V: Not conforming to UL94 standards

[0135] (2) Charpy impact strength (kJ / m 2 ) The Charpy impact strength of test specimens obtained from the flame-retardant styrene-based resin composition of the example and the resin composition of the comparative example was measured with notches in accordance with ISO 179.

[0136] (3) Weather resistance Using test specimens (a) prepared by the method described below, the Charpy impact strength was measured after 500 hours using a xenon lamp weather meter [Atlas Corporation; Ci65], maintaining the temperature of the black panel at 63°C and performing a water spray for 18 minutes out of a 120-minute cycle. The retention rate of the Charpy impact strength after 500 hours relative to the Charpy impact strength at the start of the measurement was used for evaluation. Weather resistance (Charpy impact strength retention rate) (%) = (Charpy impact strength after 500 hours) / (Charpy impact strength at the start of measurement) × 100

[0137] (4) Dielectric constant and dielectric loss tangent A specimen (a) (size: 127 mm × 12.7 mm, thickness: 1.5 mm) prepared by the method described below was cut to 80 mm × 1.5 mm and 0.8 mm thick. The dielectric constant and dielectric properties of specimen (a) obtained from the flame-retardant styrene resin composition of the example and the resin composition of the comparative example were measured at 10 GHz using a PNA-L network analyzer N5230A (manufactured by Agilent Technologies, Inc.) in accordance with IEC62810 (cavity resonator perturbation method) (200°C, load 49 N).

[0138] The materials used in the examples and comparative examples are as follows. <(A) component> < <gpps>> Polystyrene with an MFR of 2.2 (GPPS, manufactured by PS Japan, G9401) was used. < <hips>> A rubber-modified styrene resin, which is a high-impact polystyrene (HIPS) with an MFR of 7.0, was used. The matrix resin of the HIPS was polystyrene, and polybutadiene was used as the rubbery polymer. The content of the rubbery polymer was 8.6% by mass, and the average particle size of the rubbery polymer contained in the high-impact polystyrene (HIPS) was 1.5 μm.

[0139] <<Styrene-based copolymer resin>> [Copolymer resin a] A polymerization raw material composition liquid consisting of 71.3 parts by mass of styrene (ST), 7.3 parts by mass of methacrylic acid (MAA), 6.4 parts by mass of methyl methacrylate (MMA), 15.0 parts by mass of ethylbenzene, and 0.025 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane was continuously supplied at a rate of 1.1 liters / hour to a 4-liter fully mixed reactor, then to a polymerization apparatus consisting of a 2-liter laminar flow reactor, and finally to a defoliation apparatus connected to a single-screw extruder for removing volatile components such as unreacted monomers and polymerization solvents, thereby preparing a styrene copolymer resin. The polymerization reaction conditions in the polymerization process were set to a polymerization temperature of 122°C for the fully mixed reactor and 120-142°C for the laminar flow reactor. The defolatable unreacted gas was condensed by passing it through a refrigerant at -5°C. The mixture was condensed using a shrinking chamber and recovered as unreacted liquid. The styrene copolymer resin content in the final polymerization solution was measured using the formula [(mass of sample after drying / mass of sample before drying) × 100%] after drying the polymerization solution at 215°C under reduced pressure of 2.5 kPa for 30 minutes, and was found to be 65.6% by mass, with a weight-average molecular weight of 214,000 (214,000). The composition ratio of the styrene copolymer resin was 82.3% by mass of styrene monomer units, 9.8% by mass of methacrylic acid monomer units, and 7.9% by mass of methyl methacrylate monomer units. Each monomer unit is analyzed using proton nuclear magnetic resonance ( 1 The composition of the styrene copolymer resin was quantified from the integral ratio of the spectrum measured using a 1H-NMR (H-NMR) detector. Sample preparation: 30 mg of resin pellets were dissolved in 0.75 mL of d6-DMSO by heating at 60°C for 4-6 hours. ·Measuring equipment: JNM ECA-500 manufactured by JEOL Ltd. • Measurement conditions: Measurement temperature 25°C, observed nucleus 1 H, cumulative count 64 times, repetition time 11 seconds.

[0140] -Spectral Attribution- Regarding the assignment of the spectra measured in the above-mentioned DMSO (dimethyl sulfoxide deuterated solvent), the peaks at 0.5–1.5 ppm represent hydrogen atoms of the α-methyl group of methacrylic acid, methyl methacrylate, and six-membered cyclic acid anhydride; the peaks at 1.6–2.1 ppm represent hydrogen atoms of the methylene group of the polymer main chain; the peak at 3.5 ppm represents hydrogen atoms of the carboxylic acid ester (-COOCH3) of methyl methacrylate; and the peak at 12.4 ppm represents hydrogen atoms of the carboxylic acid of methacrylic acid. In addition, the peaks at 6.5–7.5 ppm represent hydrogen atoms of the aromatic ring of styrene. Note that in the resins of this example and comparative example, the content of six-membered cyclic acid anhydride is low, so quantification is usually difficult using this measurement method.

[0141] [Copolymer resin b] The composition and polymerization temperature conditions were adjusted so that the composition ratio of the styrene copolymer resin was 91.8% by mass of styrene monomer units and 8.2% by mass of methacrylic acid monomer units, and resin b was obtained in the same manner as resin a.

[0142] [Copolymer resin c] The composition and polymerization temperature conditions were adjusted so that the composition ratio of the styrene copolymer resin was 97.6% by mass of styrene monomer units and 2.4% by mass of methacrylic acid monomer units, and resin c was obtained in the same manner as resin a.

[0143] <(B) component> • Elastomer A (manufactured by Mitsubishi Chemical, S-2100, average particle size 0.8 μm) • Elastomer B (manufactured by Mitsubishi Chemical, S-2001, average particle size 0.3 μm) • Elastomer C (manufactured by Mitsubishi Chemical, S-2130, average particle size 0.8 μm) • Elastomer D (comparative) (manufactured by Mitsubishi Chemical, silicone-free W-450, average particle size 0.3 μm) • Elastomer E (comparative) (manufactured by Mitsubishi Chemical, silicone-free C-223, average particle size 0.3 μm)

[0144] <(C) component> • Phosphonic acid ester [Non-nen 73, formula (2-1), manufactured by Marubishi Oil & Chemical Industries Co., Ltd.] • Phosphinic acid compounds (also referred to as phosphinic acid in Tables 1 and 2) [HCA, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, manufactured by Sanko Co., Ltd.] • Phosphate salts (also referred to as phosphinate salts in Tables 1 and 2): "Exolit OP1230, aluminum phosphinate, manufactured by Clariant Japan Co., Ltd." • Phosphate ester (comparative) [Manufactured by Daihachi Chemical Industry Co., Ltd., CR733S, resorcinol bis(diphenyl phosphate)]

[0145] <(D) component> • Hindered amine compound A (also referred to as HALS-A in Tables 1 and 2 below) [BASF, FlamestabNOR116FF, NOR-type polymer] • Hindered amine compound B (also referred to as HALS-B in Tables 1 and 2 below) [Manufactured by ADEKA Corporation, ADEKA stub LA-81 NOR type] • Hindered amine compound C (also referred to as HALS-C in Tables 1 and 2 below) [Manufactured by ADEKA Corporation, ADEKA stub LA-77Y NH type]

[0146] <(E) component> • UV absorbers [Adekastab 1413, 2-hydroxy-4-n-octoxybenzophenone]

[0147] [Examples 1-16] Using the composition ratios shown in Table 1, each component and 100 parts by mass of components (A) to (C), and components (D) and (E) as needed, were pre-mixed. The resulting pre-mixtures were mixed together and melt-extruded using a twin-screw extruder (Toshiba Machine Co., Ltd., TEM-26SS) at a temperature of 180°C to 230°C (screw rotation speed 250 rpm, discharge volume 10 kg / hr) to produce pelletized styrene-based resin compositions. The pelletized styrene-based resin compositions thus obtained were molded using an injection molding machine manufactured by Japan Steel Works, Ltd., equipped with a double-gate flat plate mold with dimensions of 127 mm × 12.7 mm × thickness 0.8 mm, at a cylinder temperature of 220°C, a mold temperature of 50°C, an injection pressure (gauge pressure 40-60 MPa), an injection speed (panel setting value) of 50%, and an injection time / cooling time of 5 sec / 20 sec to produce test specimen (a), and their various physical properties were measured.

[0148] [Table 1]

[0149] [Comparative Examples 1-13] Comparative Examples 1 to 13 were carried out in the same manner as Example 1, except that the composition was changed as shown in Table 1. The results of the measurement and evaluation of each physical property are shown in Table 2.

[0150] [Table 2]

[0151] As shown in Table 1 above, the styrene-based resin compositions and molded articles described in Examples 1 to 16 are confirmed to have high flame retardancy, excellent impact strength, and low dielectric properties. Furthermore, they exhibit minimal decrease in impact strength after xenon irradiation and excellent weather resistance. In particular, the silicone / acrylic composite rubber graft copolymer (B) shows increased impact strength when the average particle size increases to 0.8 μm. Furthermore, it is found that using a copolymer resin as the styrene-based resin results in excellent impact strength and weather resistance.

[0152] On the other hand, as shown in Table 2 from Comparative Examples 1 and 2, flame retardancy cannot be obtained with component (B) alone.

[0153] As shown in Table 2 from Comparative Examples 3 to 5, component (B) alone may not provide sufficient impact strength and may not meet the requirements for flame retardancy and weather resistance.

[0154] As shown in Comparative Examples 6-7 and Table 2, if the amounts of component (B) or component (C) are too high, it is not possible to satisfy all requirements.

[0155] As shown in Comparative Examples 8-10 and Table 2, using an elastomer without silicone components may result in a failure to obtain flame retardancy, and may also fail to meet requirements for impact resistance and weather resistance.

[0156] As shown in Comparative Examples 11-13 and Table 2, using phosphate esters may result in a lack of weather resistance, as well as failure to meet requirements for flame retardancy, impact resistance, and low dielectric properties. [Industrial applicability]

[0157] This disclosure provides a flame-retardant styrene-based resin composition that is excellent in flame retardancy, impact resistance, weather resistance, and low dielectric properties, and a molded article containing the flame-retardant styrene-based resin composition. Molded articles containing the flame-retardant resin composition of the present invention can be suitably used in sheets, films, foams, etc., for lighting components, computer components such as desktop and notebook computers, mobile phone components, electrical and electronic equipment, personal information terminals, home appliance components, automobile components, industrial materials, and building materials.< / hips> < / gpps>

Claims

1. 45-96% by mass of styrene resin (A), A silicone / acrylic composite rubber graft copolymer (B) comprising a composite rubber containing polyorganosiloxane and polyalkyl (meth)acrylate, grafted with a vinyl polymer composed of one or more vinyl monomer units, is provided in an amount of 3 to 25% by mass. It contains 1 to 30% by mass of a phosphonic acid ester compound or a phosphinic acid compound (C), The styrene resin (A) is a polymer composed of styrene monomer units, a rubber-modified styrene resin containing a matrix resin composed of styrene monomer units and rubbery polymer particles (1), or a styrene copolymer resin containing styrene monomer units and an unsaturated carboxylic acid monomer. Furthermore, the rubbery polymer particles (1) contain a rubbery polymer (a1) which is one of polybutadiene, polyisoprene, natural rubber, polychloroprene, or styrene-butadiene copolymer, and the matrix resin. The flame-retardant styrene-based resin composition is characterized in that the styrene monomer unit is selected from the group consisting of styrene, α-methylp-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, t-butylstyrene, bromostyrene, and indene.

2. The flame-retardant styrene resin composition according to claim 1, wherein the styrene resin (A) is a styrene copolymer resin containing one or more monomer units selected from the group consisting of methacrylic acid monomer units, alkyl methacrylate monomer units, and maleic anhydride monomer units.

3. The flame-retardant styrene resin composition according to claim 1 or 2, wherein the average particle size of the silicone / acrylic composite rubber graft copolymer (B) is 0.5 to 1.2 μm.

4. The flame-retardant styrene resin composition according to any one of claims 1 or 2, further comprising 0.05 to 3 parts by mass of one or more selected from the group consisting of hindered amine compounds (D) and ultraviolet absorbers (E).

5. The flame-retardant styrene resin composition according to claim 4, wherein the hindered amine compound (D) is a NOR-type hindered amine compound.

6. A molded article comprising the flame-retardant styrene resin composition according to any one of claims 1 or 2.

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