Flame-retardant styrene resin composition and molded product

Abstract

To provide a flame-retardant styrene resin composition that excels in flame retardancy, dimensions, and low dielectric properties.SOLUTION: A flame-retardant styrene resin composition contains 40-94 mass% of a styrene resin (A), 3-30 mass% of a flame retardant (B) including a phosphinate (b), and 3-30 mass% of a glass balloon (C).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a flame-retardant styrenic resin composition and a molded article. [Background technology]

[0002] Styrene-based resins are used in a wide range of applications due to their excellent moldability, dimensional stability, and impact resistance. Among them, polystyrene-based resin compositions that have been given flame retardancy are used in a wide range of applications, including home appliances and office equipment. Conventionally, various flame retardants have been proposed for the purpose of imparting flame retardancy to polystyrene-based resin compositions. Among them, bromine-based flame retardants, which are inexpensive and have a good balance of physical properties, are widely used. However, in recent years, due to the movement to regulate halogen-containing organic compounds, mainly in Europe, there is an increasing demand for flame-retardant resins or flame-retardant resin compositions that do not contain bromine elements. In addition, low dielectric materials are required for high-frequency applications to reduce transmission loss, and low linear expansion is required for antenna substrates, which form metal circuits.

[0003] As an alternative flame retardant to such bromine-based flame retardants, for example, Patent Document 1 discloses a technique of adding a phosphinate to a thermoplastic polymer. Moreover, Patent Document 2 discloses a technique for improving dimensional accuracy by adding glass balloons to a styrene-based resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-124466 [Patent Document 2] Japanese Patent Application Publication No. 4-23848 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the above-mentioned Patent Document 1 describes that it is possible to impart flame retardancy to a polystyrene-based resin composition, the flame retardant described in Patent Document 1 has problems such as poor dispersibility in polystyrene, insufficient flame retardancy, and generation of black smoke during combustion. In addition, in the technology of the above-mentioned Patent Document 2, although dimensional accuracy is improved by blending the specific glass balloons described in Patent Document 2 into a polystyrene-based resin composition, there is no description of flame retardancy, and there is no description at all of the effect of improving flame retardancy with a specific flame retardant.

[0006] Therefore, the present disclosure provides a flame-retardant styrene-based resin composition that is excellent in flame retardancy, dimensional properties and low dielectric properties. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have surprisingly found that a resin composition in which a flame retardant (B) containing a phosphinic acid salt compound (b) and glass balloons (C) are added to a styrene-based resin (A) in a specific ratio has extremely high flame retardancy, dimensional accuracy, and low dielectric properties, and have completed the present invention. That is, the present invention is as follows.

[0008] [1] The present disclosure relates to a styrene-based resin (A) of 40 to 94% by mass, The following general formula (i): [ka] [In the above general formula (i), R i1 and R i2 are each independently unsubstituted or one or more hydrogen atoms are substituted by R i3 represents 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 is represented by the following general formula (ii): [ka] In the above general formula (ii), R ii1 each independently represents 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 to another atom. M i each independently represents at least one selected from the group consisting of a calcium ion, a magnesium ion, an aluminum ion, a zinc ion, a bismuth ion, a manganese ion, a sodium ion, a potassium ion, and a protonated nitrogen base; p + is M i represents an ionic valence of 1 to 3; m i1 represents a positive integer from 1 to 3, n - represents a negative integer of -1, -2, or -3, r represents a positive integer of 1 to 3, provided that multiple M i may be the same or different from each other, |p + ×r|=|n - ×m i1 |. | 3 to 30 mass % of a flame retardant (B) containing a phosphinate compound (b) represented by the formula: A flame-retardant styrene-based resin composition comprising: 3 to 30 mass % of glass balloons (C). [2] The flame-retardant styrenic resin composition according to [1], wherein the phosphinic acid compound (b) is at least one or more compounds selected from the group consisting of a phosphinic acid salt represented by the following general formula (1) and a diphosphinic acid salt represented by the following general formula (2): [ka] [In the above general formula (1), R 11 and R 12 each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; M 1represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen bases; + is M 1 represents an ionic valence, and represents a positive integer of 1 to 3; m 1 represents a positive integer between 1 and 3, and |a + |=|m 1 |It is. [ka] [In the above general formula (2), R 21 and R 22 each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; L 23 represents 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 represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen bases; b + is M 2 represents an ionic valence of 1 to 3, m 2 represents a positive integer of 1 to 3, q ​​represents a positive integer of 1 or 2, |b + ×q|=|2m 2 |It is. [3] The flame-retardant styrene-based resin composition according to [1] or [2], wherein the styrene-based resin (A) is a rubber-modified styrene-based resin containing rubber-like polymer particles (a) containing a rubber-like polymer (a), the content of the rubber-like polymer (a) is 8 to 15 mass %, and the average particle size of the rubber-like polymer particles (a) is 2 to 4 μm. [4] The flame-retardant styrene-based resin composition according to any one of [1] to [3], wherein the glass balloons (C) have an average particle size of 10 to 30 μm. [5] A molded article comprising the flame-retardant styrene-based resin composition according to any one of [1] to [4]. [6] An antenna substrate comprising the flame-retardant styrene-based resin composition according to any one of [1] to [4]. Effect of the Invention

[0009] According to the present invention, there is provided a flame-retardant styrene-based resin composition having excellent flame retardancy, dimensional properties and low dielectric properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following describes in detail an embodiment of the present invention (hereinafter referred to as the "present embodiment"); however, the present invention is not limited to the following description and can be implemented in various modified forms within the scope of its gist.

[0011] [Flame-retardant styrene-based resin composition] The flame-retardant styrene-based resin composition of the present embodiment contains 40 to 94 mass% of a styrene-based resin (A) (hereinafter also referred to as component (A)), 5 to 30 mass% of a flame retardant (B) (hereinafter also referred to as component (B)) containing a phosphinate compound (b), and 3 to 10 mass% of glass balloons (C) (hereinafter also referred to as component (C)). The phosphinate compound (b) is represented by the following general formula (i): [ka] [In the above general formula (i), R i1 and R i2 are each independently unsubstituted or one or more hydrogen atoms are substituted by R i3 represents 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 is represented by the following general formula (ii): [ka] In the above general formula (ii), R ii1 each independently represents 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 to another atom. i each independently represents at least one selected from the group consisting of a calcium ion, a magnesium ion, an aluminum ion, a zinc ion, a bismuth ion, a manganese ion, a sodium ion, a potassium ion, and a protonated nitrogen base; + is M i represents an ionic valence of 1 to 3, m i1 represents a positive integer from 1 to 3, n - represents a negative integer of -1, -2, or -3, and r represents a positive integer of 1 to 3, provided that multiple M i may be the same or different, and |p + ×r|=|n - ×m i1 | is represented as . This makes it possible to provide a flame-retardant styrene-based resin composition that is excellent in low smoke generation, flame retardancy, rigidity and color tone. Each component contained in the flame-retardant styrene-based resin composition will be described below.

[0012] <Styrene-based resin (A): Component (A)> In the flame-retardant styrene-based resin composition of the present embodiment, the content of the styrene-based resin (A) is 40 to 94 mass%, preferably 50 to 90 mass%, and more preferably 60 to 85 mass%, relative to 100 mass% of the total amount of the components (A), (B), and (C). If the content of the styrene-based resin (A) is less than 40 mass%, moldability decreases, while if it exceeds 94 mass%, flame retardancy and dimensional stability decrease.

[0013] 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 selected from other vinyl-based monomers copolymerizable with the styrene-based monomer and rubber-like polymer (a). In other words, the styrene-based resin (A) is preferably a polymer having a styrene-based monomer unit, and more preferably a polymer that essentially contains a styrene-based monomer unit and has, as an optional component, other vinyl-based monomers copolymerizable with the styrene-based monomer unit and / or monomer units of rubber-like polymer (a). The preferred form of the styrene resin (A) in this embodiment is not particularly limited, but specifically includes, for example, a rubber-modified styrene resin in which particles of a rubber-like polymer (a) are dispersed in a polymer matrix containing polystyrene, a polystyrene polymer (polystyrene and / or a polystyrene-unsaturated carboxylic acid polymer, etc.), or a styrene copolymer resin. In addition, a styrene polymer having a syndiotactic structure can also be used as the styrene resin (A).

[0014] <<Polystyrene>> In this embodiment, polystyrene is a homopolymer obtained by polymerizing a styrene-based monomer, and generally available ones can be appropriately selected and used. In addition to styrene, the styrene-based monomer constituting polystyrene includes α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and t-butylstyrene, or styrene derivatives such as bromostyrene and indene. Styrene is particularly preferred from an industrial viewpoint. One or more of these styrene-based monomers can be used. Polystyrene typically consists of styrene-based monomer units, although it is not excluded that polystyrene further contains monomer units other than the above-mentioned styrene-based monomer units within a range that does not impair the effects of the present invention.

[0015] <<Rubber-modified styrene resin>> In this embodiment, the rubber-modified styrene-based resin is a resin in which particles of a rubber-like polymer (a) (also referred to as rubber-like polymer particles (a)) are dispersed in a styrene-based polymer having styrene-based monomer units as a polymer matrix that is a continuous phase, and can be produced by polymerizing a styrene-based monomer and, if necessary, a (meth)acrylic acid-based monomer ((meth)acrylic acid and (meth)acrylic acid alkyl ester) in the presence of the rubber-like polymer (a).

[0016] Examples of the styrene monomer constituting the rubber-modified styrene resin of the present embodiment include, in addition to styrene, α-methylstyrene, α-methyl p-methylstyrene, ο-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutylstyrene, and t-butylstyrene, or styrene derivatives such as bromostyrene and indene. Styrene is particularly preferred. These styrene monomers can be used alone or in combination.

[0017] The rubber-like polymer particles (a) contained in the rubber-modified styrene-based resin of this embodiment may, for example, contain a resin containing a styrene monomer unit obtained from the above-mentioned styrene-based monomer inside the rubber-like polymer particles (a), and / or may be rubber-like polymer particles (a) having a resin containing a styrene monomer unit grafted onto the surface thereof.

[0018] As the rubber-like polymer (a), for example, a rubber component such as polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc. can be used. The rubber component may also include a form containing polystyrene and / or polystyrene-unsaturated carboxylic acid polymer. Among them, the rubber-like polymer (a) is preferably polybutadiene or styrene-butadiene copolymer. As the polybutadiene, both high-cis polybutadiene having a high cis content and low-cis polybutadiene having a low cis content can be used. In addition, both random structure and block structure can be used as the structure of the styrene-butadiene copolymer. These rubber-like polymers (a) can be used alone or in combination. In addition, saturated rubber obtained by hydrogenating butadiene rubber can also be used.

[0019] Examples of such rubber-modified styrene-based 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).

[0020] When the rubber-modified styrene resin is a HIPS resin, the particularly preferred rubber polymer (a) is a high-cis polybutadiene having 90 mol % or more of cis-1,4 bonds. In the high-cis polybutadiene, the vinyl 1,2 bonds are preferably 6 mol % or less, and more preferably 3 mol % or less. The content of isomers having a cis-1,4 structure, a trans-1,4 structure, or a vinyl-1,2 structure as the structural unit of the isomeric polybutadiene can be measured using an infrared spectrophotometer and calculated by processing the data using the Morello method. The high-cis polybutadiene can be easily obtained by a known production method, for example, by polymerizing 1,3-butadiene using a catalyst containing an organoaluminum compound and a cobalt or nickel compound.

[0021] The content of the rubber-like polymer (a) contained in the rubber-modified styrene-based resin (not including the styrene-based resin (A) as the polymer matrix (or styrene-based polymer) incorporated in the rubber-like polymer (a) particles) is preferably 3 to 20 mass%, more preferably 8 to 15 mass%, based on 100 mass% of the total amount of the rubber-modified styrene-based resin. If the content of the rubber-like polymer (a) is less than 3 mass%, the impact resistance of the styrene-based resin (A) may decrease. If the content of the rubber-like polymer (a) exceeds 20 mass%, the flame retardancy may decrease. In particular, since the phosphinate compound (b) and the glass balloons (C) are present as fillers in the resin, the content of the rubber-like polymer (a) is more preferably 8 to 15 mass% in order to improve the impact strength.

[0022] In the present disclosure, the content of the rubber-like polymer (a) contained in the rubber-modified styrene-based resin is a value calculated using pyrolysis gas chromatography.

[0023] The average particle size of the rubber-like polymer particles (a) contained in the rubber-modified styrene-based resin is preferably 1 to 5 μm, more preferably 2 to 4 μm, from the viewpoints of impact resistance and flame retardancy. In this flame-retardant styrene-based resin composition, when the average particle size is 2 to 4 μm, the impact strength is significantly improved.

[0024] In the present disclosure, the average particle size of the rubber-like polymer particles (a) contained in the rubber-modified styrene-based resin can be measured by the following method. A 75 nm-thick ultrathin section is prepared from the rubber-modified styrene-based resin stained with osmium tetroxide, and three photographs are taken at a magnification of 10,000 times using an electron microscope. Among the three photographs, the particles stained black are rubber-like polymer particles (a). From the three photographs, the following formula (N1): Average particle diameter=ΣniDri 3 / ΣniDri 2 (N1) (In the above formula (N1), ni is the total number of rubber-like polymer particles (a) having a particle diameter Dri present in the three photographs, and the particle diameter Dri is the particle diameter calculated as a circle-equivalent diameter from the area of ​​the particles in the three photographs.) The area-average particle size is calculated from the above and is regarded as the average particle size of the rubber-like polymer particles (a). In this measurement, a photograph is scanned at a resolution of 200 dpi, and the measurement is performed using particle analysis software of an image analyzer IP-1000 (manufactured by Asahi Kasei Corporation).

[0025] The reduced viscosity of the rubber-modified styrene-based resin (which is an index of the molecular weight of the rubber-modified styrene-based resin) is preferably in the range of 0.50 to 0.85 dL / g, more preferably in the range of 0.55 to 0.80 dL / g. If it is less than 0.50 dL / g, there is a risk of a decrease in impact strength, and if it exceeds 0.85 dL / g, there is a risk of a decrease in moldability due to a decrease in fluidity.

[0026] In this disclosure, the reduced viscosity of the rubber-modified styrene-based resin is a value measured in a toluene solution at 30° C. and a concentration of 0.5 g / dL.

[0027] The method for producing the rubber-modified styrene-based resin is not particularly limited, but it can be produced by bulk polymerization (or solution polymerization) in which a styrene-based monomer (and a solvent) is polymerized in the presence of the rubber-like polymer (a), or bulk-suspension polymerization in which the reaction is changed to suspension polymerization during the course of the reaction, or emulsion graft polymerization in which a styrene-based monomer is polymerized in the presence of the rubber-like polymer (a) latex. In bulk polymerization, the rubber-like polymer (a) can be produced by continuously supplying a mixed solution containing the rubber-like polymer (a) and the styrene-based monomer, and optionally an organic solvent, an organic peroxide, and / or a chain transfer agent, to a polymerization apparatus consisting of a complete mixing reactor or a tank reactor and a plurality of tank reactors connected in series.

[0028] <<Styrene-based copolymer resin>> In the present embodiment, the styrene-based copolymer resin is a resin containing a styrene-based monomer unit and other monomers (e.g., unsaturated carboxylic acid-based monomer units) copolymerizable with the styrene-based monomer. For example, when the other monomers are unsaturated carboxylic acid-based monomer units, the styrene-based copolymer resin according to the present invention has a styrene-based monomer unit content of preferably 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 the styrene-based monomer units and the unsaturated carboxylic acid-based monomer units is taken as 100% by mass. By making the content 69% by mass or more, the flowability of the resin can be improved. On the other hand, by making the content of the styrene-based monomer unit 98% by mass or less, it becomes difficult to make a desired amount of an unsaturated carboxylic acid-based monomer unit, which is an example of the other monomer, exist, and it becomes difficult to obtain the effects described below due to these monomer units.

[0029] The unsaturated carboxylic acid monomer in the present embodiment includes an unsaturated carboxylic acid monomer and an unsaturated carboxylic acid ester monomer.

[0030] In the preferred styrene-based copolymer resin of this embodiment, the unsaturated carboxylic acid monomer unit plays a role in improving heat resistance. When the total content of the styrene-based monomer unit, the unsaturated carboxylic acid monomer unit, and the unsaturated carboxylic acid ester monomer unit in the styrene-based copolymer resin is taken as 100% by mass, the content of the unsaturated carboxylic acid monomer unit is preferably 2 to 16% by mass, more preferably 4 to 14% by mass, and even more preferably 8 to 13% by mass. By making the content 2% by mass or more, the dispersibility of the (B) component and the (C) component is improved, and the impact resistance, flame retardancy, and dimensional accuracy can be further improved. On the other hand, by making the content 16% by mass or less, the molded appearance, the resin fluidity, and the mechanical properties are further improved.

[0031] Generally, styrene-methacrylic acid-based resins including styrene-methacrylic acid-methyl methacrylate copolymer resins, which are one form of the styrene-based copolymer resins in the present invention, are mostly produced by radical polymerization on an industrial scale. However, in this embodiment, in order to suppress the gelling reaction in the devolatilization step, various alcohols can be added to the polymerization system to carry out the polymerization.

[0032] The unsaturated carboxylic acid ester monomer can be used to suppress the dehydration reaction of the unsaturated carboxylic acid monomer through intermolecular interaction with the unsaturated carboxylic acid monomer and to improve the mechanical strength of the resin. Furthermore, the unsaturated carboxylic acid ester monomer also contributes to improving the resin properties such as weather resistance and surface hardness.

[0033] In this embodiment, when the total content of the styrene monomer unit, the unsaturated carboxylic acid monomer unit, and the unsaturated carboxylic acid ester monomer unit is taken as 100% by mass, the content of the unsaturated carboxylic acid ester monomer unit 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, the fluidity of the resin can be improved and water absorption can be suppressed. In addition, by setting the lower limit of the content of the unsaturated carboxylic acid ester monomer unit to 0% by mass, the heat resistance can be improved and the cost can be reduced, but from the above viewpoint, the content of the unsaturated carboxylic acid ester monomer unit can also be set to more than 0% by mass.

[0034] In addition, when an unsaturated carboxylic acid monomer and an unsaturated carboxylic acid ester monomer unit are bonded side by side, if a high-temperature, high-vacuum devolatilizer is used, a dealcoholization reaction may occur under certain conditions, resulting in the formation of a six-membered cyclic acid anhydride. The styrene-based copolymer resin of the present embodiment may contain this six-membered cyclic acid anhydride, but since this reduces the fluidity, it is preferable that the amount of the six-membered cyclic acid anhydride produced is as small as possible.

[0035] In the present embodiment, the contents of the styrene-based monomer unit (e.g., styrene monomer unit), the unsaturated carboxylic acid monomer unit (e.g., methacrylic acid monomer unit), and the unsaturated carboxylic acid ester monomer unit (e.g., methyl methacrylate monomer unit) in the styrene-based copolymer resin are respectively measured by proton nuclear magnetic resonance ( 1 It can be calculated from the integral ratio of the spectrum measured by a H-NMR spectrometer.

[0036] In the present embodiment, the styrene-based copolymer resin may further contain monomer units other than the styrene-based monomer units and unsaturated carboxylic acid-based monomer units (e.g., unsaturated carboxylic acid monomer units and unsaturated carboxylic acid ester monomer units), which are examples of other monomers, within a range that does not impair the effects of the present invention. However, the styrene-based copolymer resin in the present invention is preferably typically composed of styrene-based monomer units, unsaturated carboxylic acid monomer units, and / or unsaturated carboxylic acid ester monomer units.

[0037] The styrene-based monomer constituting the styrene-based copolymer resin of the present embodiment is not particularly limited, but examples thereof 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 viewpoint, styrene is preferred as the styrene-based monomer. These styrene-based monomers can be used alone or in combination of two or more.

[0038] The unsaturated carboxylic acid monomer constituting the styrene-based copolymer resin of the present embodiment is not particularly limited, but examples thereof include (meth)acrylic acid, specifically, methacrylic acid, acrylic acid, maleic anhydride, maleic acid, fumaric acid, itaconic acid, etc. As the unsaturated carboxylic acid monomer, methacrylic acid is preferred because it has a large effect of improving heat resistance, is liquid at room temperature, and has excellent handling properties. These unsaturated carboxylic acid monomers can be used alone or in combination of two or more.

[0039] The unsaturated carboxylate monomer constituting the styrene copolymer resin of the present embodiment is not particularly limited, but may be, for example, (meth)acrylic acid ester, specifically, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. As the (meth)acrylic acid ester monomer, methyl (meth)acrylate is preferred because it has little effect on the decrease in heat resistance. These unsaturated carboxylate monomers may be used alone or in combination of two or more.

[0040] 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, and styrene-maleic anhydride copolymer.

[0041] 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 further preferably 140,000 to 240,000. When the weight average molecular weight (Mw) is 100,000 to 350,000, a resin having a better balance between mechanical strength and fluidity is obtained, and the amount of gel contamination is small. The weight average molecular weight (Mw) is a value obtained by using gel permeation chromatography and converting it into standard polystyrene.

[0042] In the present embodiment, the polymerization method for the styrene-based polymer resin is not particularly limited, but for example, a bulk polymerization method or a solution polymerization method can be suitably adopted as a radical polymerization method. The polymerization method mainly includes a polymerization step of polymerizing the polymerization raw materials (monomer components) and a devolatilization step of removing volatile matters such as unreacted monomers and polymerization solvent from the polymerization product.

[0043] Hereinafter, an example of a polymerization method for the styrene-based copolymer resin that can be used in the present embodiment will be described.

[0044] When the polymerization raw materials are polymerized to obtain a styrene-based copolymer resin, a polymerization initiator and a chain transfer agent are typically contained in the polymerization raw material composition.

[0045] Examples of the polymerization initiator used in the polymerization of the styrene-based copolymer resin include organic peroxides, such as peroxyketals such as 2,2-bis(t-butylperoxy)butane, 1,1-bis(t-butylperoxy)cyclohexane, and n-butyl-4,4-bis(t-butylperoxy)valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, and dicumyl peroxide, diacyl peroxides such as acetyl peroxide and isobutyryl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxyesters such as t-butyl peroxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butyl hydroperoxide. Among them, 1,1-bis(t-butylperoxy)cyclohexane is preferred from the viewpoint of decomposition rate and polymerization rate.

[0046] Examples of the chain transfer agent used in the polymerization of the styrene-based copolymer resin include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan.

[0047] As a polymerization method for the styrene-based copolymer resin, solution polymerization using a polymerization solvent can be adopted as necessary. Examples of the polymerization solvent used include aromatic hydrocarbons, such as ethylbenzene, and dialkyl ketones, such as methyl ethyl ketone, and each of them may be used alone or in combination of two or more. Other polymerization solvents, such as aliphatic hydrocarbons, can be further mixed with aromatic hydrocarbons as long as the solubility of the polymerization product is not reduced. These polymerization solvents are preferably used in an amount not exceeding 25 parts by mass relative to 100 parts by mass of the total monomers. If the amount of the polymerization solvent exceeds 25 parts by mass relative to 100 parts by mass of the total monomers, the polymerization rate is significantly reduced and the mechanical strength of the obtained resin tends to be significantly reduced. It is preferable to add the polymerization solvent at a ratio of 5 to 20 parts by mass relative to 100 parts by mass of the total monomers before polymerization, as this makes it easier to uniformize the quality and is also preferable in terms of polymerization temperature control.

[0048] In this embodiment, the apparatus used in the polymerization step for obtaining a styrene-based copolymer resin is not particularly limited, and may be appropriately selected according to a general polymerization method for styrene-based resins. For example, when bulk polymerization is employed, a polymerization apparatus having one or more completely mixed reactors connected together can be used. There is also no particular limitation on the devolatilization step. When bulk polymerization is employed, polymerization is continued until the final amount of unreacted monomer is preferably 50 mass% or less, more preferably 40 mass% or less, and devolatilization treatment is performed by a known method in order to remove volatile matters such as unreacted monomer. More specifically, for example, a normal devolatilization apparatus such as a flash drum, a twin-screw devolatilizer, a thin film evaporator, or an extruder can be used, but a devolatilization apparatus with a small retention portion is preferred. The temperature of the devolatilization treatment is usually about 190 to 280°C, and from the viewpoint of suppressing the formation of a six-membered ring acid anhydride due to the adjacency of an unsaturated carboxylic acid monomer (e.g., methacrylic acid) and an unsaturated carboxylic acid ester monomer (e.g., methyl methacrylate), 190 to 260°C is more preferred. The pressure in the devolatilization treatment is usually about 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, a method of removing volatile matters by reducing pressure under heating, and a method of removing volatile matters through an extruder or the like designed for the purpose of removing volatile matters.

[0049] <Flame retardant (B): (B) component> The flame-retardant styrene-based resin composition of the present embodiment contains 3 to 30 mass% of the flame retardant (B) relative to 100 mass% of the flame-retardant styrene-based resin composition, preferably 5 to 29 mass%, more preferably 8 to 28 mass%, and even more preferably 10 to 25 mass%. The flame retardant (B) of the present embodiment contains a phosphinate compound (b) represented by general formula (i). In this case, the proportion (mass%) of the phosphinate compound (b) in the flame retardant (B) is preferably 50 to 100 mass%. In the present embodiment, the content of the phosphinate compound (b) is more preferably 70% by mass or more relative to 100% by mass of the total amount of the flame retardant (B). Therefore, the flame retardant (B) may contain 30% by mass or less of a known flame retardant other than the phosphinate compound (b) and / or an optional additive component (such as an antioxidant or an ultraviolet ray inhibitor) described later relative to 100% by mass of the total amount of the flame retardant (B). In the present embodiment, the phosphinate compound (b) is represented by the following general formula (i) and preferably contains at least one phosphinate selected from a phosphinate and a diphosphinate, and more preferably the phosphinate accounts for 70 mass% or more of the entire phosphinate compound (b) (100 mass%). The following general formula (i): [ka] [In the above general formula (i), R i1 and R i2 are each independently unsubstituted or one or more hydrogen atoms are substituted by R i3 represents 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 is represented by the following formula (ii): [ka] In the above formula (ii), R ii1 each independently represents 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 to another atom. M i represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen bases; p + is M i represents an ionic valence of 1 to 3, m i1 represents a positive integer from 1 to 3, and n -represents a negative integer of -1, -2, or -3; r represents a positive integer of 1 to 3; |p + ×r|=|n - ×m i1 | Also, R i1 and R ii1 If there are multiple of each, i1 and R ii1 may be the same or different.] Therefore, the phosphinate compound (b) in this embodiment may contain a known flame retardant other than the phosphinate represented by general formula (i) in an amount of 30 mass% or less relative to the entire phosphinate compound (b) (100 mass%). In the above formula (i), M i The ionic valence of "p + The absolute value of the product of " and "r" is "n - " and "m i1 " is equal to the absolute value of the product. In (i) above, p + is preferably 1 or 2. i1 is preferably 1 or 2. - is preferably -1 or -2. r is preferably 1 or 2. In addition, M i If there are multiple M i may be the same or different.

[0050] In this embodiment, a preferred phosphinate compound (b) is represented by the following general formula (1). [ka] [In the above general formula (1), R 11 and R 12 each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; M 1 represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen base; a represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen base; 1represents an ionic valence, and represents an integer of 1 to 3; m 1 represents an integer from 1 to 3; a=m 1 R 11 and R 12 If there are multiple of each, 11 and R 12 may be the same or different.]

[0051] In this embodiment, a preferred diphosphinate is represented by the following general formula (2). [ka] [In the above general formula (2), R 21 and R 22 each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; L 23 represents 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 represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen base; b represents at least one selected from the group consisting of M 2 represents an ionic valence, and represents an integer of 1 to 3; m 2 represents an integer of 1 to 3; q represents an integer of 1 or 2; |b + ×q|=|2×m 2 | 21 and R 12 If there are multiple of each, 21 and R 22 may be the same or different.

[0052] In the above general formulas (i), (ii), (1), and (2), examples of the linear or branched alkyl group having 1 to 6 carbon atoms include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, or a hexyl group, and branched alkyl groups such as an isopropyl group, an isobutyl group, a s-butyl group, a t-butyl group, an isoamyl group, or a t-amyl group. In the above general formulae (i), (ii), (1) and (2), the aryl group having 6 to 10 carbon atoms may have a monocyclic or condensed ring structure, for example, a phenyl group or a naphthyl group. In the above general formula (2), examples of the linear or branched alkylene group having 1 to 10 carbon atoms include groups in which one hydrogen atom has been removed from the above linear or branched alkyl group having 1 to 6 carbon atoms. In the above general formula (2), examples of the arylene group having 6 to 10 carbon atoms include groups in which one hydrogen atom has been removed from the above aryl group having 6 to 10 carbon atoms. In the above general formula (i), examples of the aralkyl group having 6 to 14 carbon atoms include 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, and a tert-butylnaphthyl group. In the above general formula (2), examples of the alkylarylene group having 6 to 14 carbon atoms include a methylphenylene group, an ethylphenylene group, a tert-butylphenylene group, a methylnaphthylene group, an ethylnaphthylene group, and a tert-butylnaphthylene group. In the above general formula (2), examples of the arylalkylene group having 6 to 14 carbon atoms include a phenylmethylene group, a phenylethylene group, a phenylpropylene group, and a phenylbutylene group. In the above general formula (1), R 11 and R 12 is preferably each independently a linear alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. In the above general formula (1), M 1is preferably calcium, magnesium, aluminum, or zinc. + is M 1 represents the ionic valence, which is 2 or 3. In the above general formula (2), R 21 and R 22 is preferably each independently a linear alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. In the above general formula (2), L 23 are each 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 general formula (2), M 2 is preferably calcium, magnesium, aluminum, or zinc. + is M 2 represents the ionic valence, which is 2 or 3. The above-mentioned phosphinic acid salt compound (b) has excellent electrical properties and is therefore suitable for flame-retardant materials that require insulation. It also has excellent hydrolysis properties and can be used in applications under high temperature and high humidity conditions. It also has excellent recyclability.

[0053] The phosphinate compound (b) used in the present embodiment is produced in an aqueous solution using, inter alia, phosphinic acid and a metal carbonate, metal hydroxide or metal oxide, and is essentially a monomeric compound, but also includes polymeric phosphinates with a condensation degree of 1 to 3 under certain circumstances, depending on the reaction conditions.

[0054] Such a phosphinate compound (b) is not particularly limited, and examples thereof include 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 methane di(methylphosphinate), magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), benzene-1 Examples of the methylphenylphosphinate include magnesium 1,4-dimethylphosphinate, aluminum 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. Of these, calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, aluminum ethylbutylphosphinate, aluminum dibutylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, and zinc diethylphosphinate are preferred, and aluminum diethylphosphinate is more preferred. Commercially available phosphinate compounds (b) are not particularly limited, and examples thereof include Exolit (registered trademark) OP1230, OP1240, OP1311, OP1312, OP930, and OP935 manufactured by Clariant Japan K.K.

[0055] In this embodiment, the phosphinate compound (b) is preferably granular. When the phosphinate compound (b) is granular, the average particle size of the phosphinate compound (b) 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-based resin composition of this embodiment, and it is preferable to use the powder of the phosphinate compound (b) pulverized to these average particle sizes. The average particle size of the phosphinate compound (b) is preferably more than 0.5 μm and 20 μm, more preferably more than 1 μm and 10 μm or less, and even more preferably more than 1 μm and 5 μm or less. When a powder with a preferred particle size is used, not only high flame retardancy is exhibited, but also dimensional accuracy is remarkably increased, which is particularly preferable. When the average particle size of the glass balloons (C) is smaller than that of the phosphinate compound (b), the phosphinate compound (b) adheres (or clings) to the periphery of the glass balloons (C), thereby improving the dispersibility of each component (particularly the glass balloons (C) or the phosphinate compound (b)) in the flame-retardant styrene-based resin composition and reducing the destruction of the glass balloons (C), thereby providing a flame-retardant styrene-based resin composition with excellent flame retardancy, dimensional accuracy, and low dielectric properties. When the phosphinate compound (b) is granular, the average particle size of the granular phosphinate compound (b) is measured based on the volumetric particle size measured using a laser diffraction / scattering particle size distribution measuring device. The value is measured using a 3% isopropanol aqueous solution as the dispersion medium of the phosphinate compound (b). Specifically, the average particle size can be obtained by using a laser diffraction / scattering particle size distribution measuring device LA-910 (manufactured by Horiba, Ltd.) to perform a blank measurement using a dispersion medium of 3% isopropanol aqueous solution, and then putting the measurement sample so that the transmittance is the specified value (95% to 70%). The sample is dispersed in the dispersion medium by irradiating ultrasonic waves for 1 minute.

[0056] <Glass Balloons (C) (hereinafter also referred to as "Component (C)")> The content of the glass bubbles (C) in this embodiment is 3 to 30 mass%, preferably 5 to 25 mass%, and more preferably 8 to 20 mass%, based on 100 mass% of the flame-retardant styrene-based resin composition. By making the content of the glass bubbles (C) 3 mass% or more, it is possible to improve the dimensional accuracy and low dielectric properties. On the other hand, if the content is too much more than 30 mass%, the moldability is significantly reduced due to a decrease in fluidity.

[0057] The glass balloons (C) in this embodiment are spherical particles made of glass and may be hollow bodies having voids inside. In one embodiment of the glass balloons (C), the material of the glass balloons (C) may be borosilicate glass, quartz glass, soft glass, soda-lime glass, lead glass, aluminosilicate glass, or the like. These materials inherently have a large dielectric tangent, but the presence of voids inside reduces the dielectric tangent. The spherical particles referred to here do not have to be perfect spheres, and may be, for example, particles with a sphericity of 0.3 to 1.0. That's fine. The median diameter of the glass balloons (C) in this embodiment is preferably 5 to 100 μm, more preferably 10 to 50 μm, and further preferably 15 to 30 μm. If it is more than 100 μm, the flame retardancy and the molded appearance are deteriorated, and if it is less than 5 μm, the improvement in the flame retardancy is insufficient. The median diameter of the glass bubbles in this embodiment can be a value measured as follows. With the glass balloons (C) dispersed in water, a laser diffraction / scattering particle size distribution analyzer (HORIBA, LTD.'s "LA-950") is used to obtain the particle size distribution of the glass balloons (C). Based on the obtained cumulative volume distribution diagram of the particle size distribution of the glass balloons (C), the arithmetic mean particle size of the glass balloons is calculated, and the particle size at the cumulative percentage of 50% (D50) is taken as the median size. Note that the particle size range of the particles for which the particle size distribution of the glass balloons (C) was obtained in the above measurement was 1 μm or more and 1000 μm or less.

[0058] The amount of voids contained in the glass balloons (C) of this embodiment can be expressed as the volumetric hollow ratio shown in the following formula (S1). Volumetric hollow ratio (%) = 100 × (1-ρ1 / ρ2) (S1) (In the above formula (S1), ρ1 is the apparent specific gravity (g / cm 3 ) and ρ2 is the material density (true density) of the glass balloon (C) (g / cm 3 )

[0059] The apparent specific gravity ρ1 of the glass balloons (C) in this embodiment is a value measured by a gas displacement method. Meanwhile, the material specific gravity ρ2 of the glass balloons (C) in this embodiment is a nominal value provided by the manufacturer. In another embodiment, the material specific gravity ρ2 of the glass balloons (C) may be measured by crushing the glass balloons (C) in a mortar to obtain crushed material, and then measuring the specific gravity of the crushed material using a pycnometer.

[0060] The volumetric hollow ratio of the glass balloons (C) of this embodiment is preferably 60% or more. When the volumetric hollow ratio of the glass balloons (C) is 60% or more, the dielectric loss tangent and specific gravity of the molded article of the obtained resin composition can be kept sufficiently low. Furthermore, the volumetric hollow ratio of the glass balloons (C) is preferably 90% or less. When the volumetric hollow ratio of the glass balloons (C) is 90% or less, the thickness of the glass balloons (C) is sufficiently large and the pressure resistance of the glass balloons (C) is sufficiently high. As a result, the crushing of the glass balloons (C) during melt-kneading and molding can be suppressed. The volumetric hollow ratio of the glass balloons (C) is preferably 60% or more and 90% or less.

[0061] The strength of the glass balloons (C) of this embodiment can be expressed by pressure resistance. The pressure resistance of the glass balloons (C) can be a value measured according to ASTM D3102-72; "Hydrostatic Collapse Strength of Hollow Glass Microspheres".

[0062] The pressure resistance of the glass balloons (C) of this embodiment is preferably 40 to 200 MPa, more preferably 80 MPa or more, and even more preferably 100 MPa or more. When the pressure resistance of the glass balloons (C) is 40 MPa or more, crushing of the glass balloons (C) during melt kneading or molding can be suppressed. As a result, the specific gravity of the molded article of the resin composition can be kept sufficiently low.

[0063] <Dispersant> In this embodiment, a dispersant may be contained in the styrene-based resin composition or the styrene-based resin molded product in order to improve the dispersibility of the flame retardant (B) and the glass balloons (C). The dispersant may be added in an amount of 0.5 to 20 parts by weight per 100 parts by weight of the total of the (A), (B), and (C) components. By adding the dispersant, it is possible to prevent scorching and eye discharge of the extruder when the flame retardant (B) and the glass balloons (C) are compounded with the styrene-based resin (A), and to improve the appearance of the molded product. If the amount of the dispersant is less than the specified amount, such an effect is not obtained, and if the amount is more than the specified amount, the heat resistance is reduced. The effect is greater if the dispersant has excellent affinity with the styrene-based resin (A).

[0064] The dispersant may be a fatty acid ester compound, a polyethylene glycol compound, a terpene compound, a rosin compound, a fatty acid amide, a fatty acid, a fatty acid metal salt, etc. In particular, fatty acid ester compounds, polyethylene glycol compounds, terpene compounds, and rosin compounds are preferred. Examples of the 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, coconut fatty acid octyl ester, octyl stearate, tallow fatty acid octyl ester, lauryl laurate, stearyl stearate, behenyl behenate, cetyl myristate, esters of linear, unbranched, saturated monocarboxylic acid having 28 to 30 carbon atoms (hereinafter abbreviated as montanic acid) and ethylene glycol, esters of montanic acid and glycerin, ... Examples of such esters include esters of montanic 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, polyoxyethylene sorbitan trioleate, etc. These may be used in combination of two or more kinds.

[0065] The terpene resin is generally obtained by copolymerizing a terpene monomer alone, or a terpene monomer and an aromatic monomer, or a terpene monomer and a phenol in an organic solvent in the presence of a Friedel-Crafts catalyst, but is not limited thereto. It may also be a hydrogenated terpene resin obtained by hydrogenating the obtained terpene resin. Examples of the terpene resin include α-pinene resin, β-pinene resin, aromatic modified terpene resin, terpene phenol resin, and hydrogenated terpene resin. Examples of the terpene monomer include, but are not limited to, hemiterpenes having 5 carbon atoms such as isoprene, α-pinene, β-pinene, dipentene, d-limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, sabinene, paramentadienes, and carenes, monoterpenes having 10 carbon atoms such as caryophyllene and longifolene, and diterpenes having 20 carbon atoms. Among these compounds, α-pinene, β-pinene, dipentene, and d-limonene are particularly preferably used. Examples of aromatic monomers include, but are not limited to, styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, etc. Examples of phenols include, but are not limited to, phenol, cresol, xylenol, bisphenol A, etc.

[0066] Examples of the rosin-based resin include rosins such as gum rosin, wood rosin, and tall oil rosin, as well as stabilized rosins obtained by disproportionating or hydrogenating the rosins, polymerized rosins (typically dimers) which are polymers of the rosins, and modified rosins modified with unsaturated acids such as maleic acid, fumaric acid, and (meth)acrylic acid. Examples of the rosin derivative resin include esters of the rosin-based resins, phenol-modified products, and esters thereof. The rosin-based resins or rosin derivative resins used in the present invention are not limited to these resins.

[0067] Examples of the aliphatic amide lubricants include stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, and ethylene bislauric acid amide. These may be used in combination of two or more kinds.

[0068] Specific examples of saturated fatty acids among the above fatty acids include lauric acid (dodecanoic acid), isodecanoic acid, tridecyl acid, myristic acid (tetradecanoic acid), pentadecylic acid, palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), isostearic acid, tuberculostearic acid (nonadecanoic acid), 2-hydroxystearic acid, arachidic acid (icosanoic acid), behenic acid (docosanoic acid), lignoceric acid (tetradocosanoic acid), cerotic acid (hexadocosanoic acid), montanic acid (octadocosanoic acid), and melissic acid, and in particular, lauric acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, and montanic acid.

[0069] Specific examples of unsaturated fatty acids among the above 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 (icosanoic acid), erucic acid (docosanoic acid), and nervonic acid (tetradocosanoic acid). These may be used in combination of two or more kinds.

[0070] Examples of the fatty acid metal salt lubricant include lithium salts, calcium salts, magnesium salts, zinc salts, and aluminum salts of the fatty acid of the fatty acid lubricant. These may be used in combination of two or more kinds.

[0071] <Optional addition ingredients> In this embodiment, the flame-retardant styrene-based resin composition may contain optional components such as conventionally known additives, processing aids, etc., in addition to the above-mentioned components (A) to (C), as necessary, within the scope of not impairing the effects of the present invention. Examples of these optional components include antioxidants, weathering agents, antistatic agents, dispersants, fillers, etc.

[0072] Examples of the antioxidant include phenol-based compounds, phosphorus-based compounds, and thioether-based compounds. Examples of the phenol-based antioxidant include 2,6-di-t-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, distearyl (3,5-di-t-butyl-4-hydroxybenzyl)phosphonate, 1,6-hexamethylenebis[(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid amide], 4,4'-thiobis(6-t-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4, 4'-butylidenebis(6-t-butyl-m-cresol), 2,2'-ethylidenebis(4,6-di-t-butylphenol), 2,2'-ethylidenebis(4-tert-butyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-t-butylbenzyl)isocyanurate, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, hydroxybenzyl)-2,4,6-trimethylbenzene, 2-t-butyl-4-methyl-6-(2-acryloyloxy-3-t-butyl-5-methylbenzyl)phenol, stearyl [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], tetrakis [methyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, thiodiethylene glycol bis[(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylene bis[(3,5-di-t-butyl-4-hydroxyphenyl)propionate] oxyphenyl)propionate], bis[3,3-bis(4-hydroxy-3-t-butylphenyl)butyric acid] glycol ester, bis[2-t-butyl-4-methyl-6-(2-hydroxy-3-t-butyl-5-methylbenzyl)phenyl] terephthalate, 1,3,5-tris[(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxyethyl] isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,Examples include 10-tetraoxaspiro[5,5]undecane, triethylene glycol bis[(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], etc. These may be used alone or in combination of two or more.

[0073] Examples of the phosphorus-based antioxidant include tris(2,4-di-t-butylphenyl)phosphite, trisnonylphenyl phosphite, tris[2-t-butyl-4-(3-t-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl]phosphite, tridecyl phosphite, octyldiphenyl phosphite, di(decyl)monophenyl phosphite, di(tridecyl)pentaerythritol diphosphite, di(nonylphenyl)pentaerythritol diphosphite, and the like. ritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-t-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetra(tridecyl)isopropylidenediphenol diphosphite, tetra(tridecyl)-4,4' -n-butylidenebis(2-t-butyl-5-methylphenol)diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butanetriphosphite, tetrakis(2,4-di-t-butylphenyl)biphenylene diphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-t-butylphenyl)-2-ethylhexylphosphite phosphite, 2,2'-methylenebis(4,6-t-butylphenyl)-octadecylphosphite, 2,2'-ethylidenebis(4,6-di-t-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetrakis-t-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]ethyl)amine, and phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-t-butylphenol. These may be used alone or in combination of two or more.

[0074] Examples of the thioether antioxidant include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and pentaerythritol tetra(β-alkylmercaptopropionate esters). These may be used alone or in combination of two or more.

[0075] As the weather resistance agent, an ultraviolet absorber, a hindered amine light stabilizer, etc. can be used. Examples of the ultraviolet absorber include 2-hydroxybenzophenones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone); 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, and the like. 2-(2'-hydroxyphenyl)benzotriazoles such as 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, 2,2'-methylenebis(4-t-octyl-6-(benzotriazolyl)phenol), and 2-(2'-hydroxy-3'-t-butyl-5'-carboxyphenyl)benzotriazole; phenyl salicylate Benzoates such as 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 2,4-di-t-amylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate; substituted oxanilides such as 2-ethyl-2'-ethoxyoxanilide and 2-ethoxy-4'-dodecyloxanilide; ethyl-α-cyano-β,β-diphenylacrylate, methyl cyanoacrylates such as aryl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate; and triaryltriazines such as 2-(2-hydroxy-4-octoxyphenyl)-4,6-bis(2,4-di-t-butylphenyl)-s-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-s-triazine, and 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-di-t-butylphenyl)-s-triazine. These may be used alone or in combination of two or more.

[0076] Examples of the hindered amine-based light stabilizer include 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-butane tetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butane tetracarboxylate, bis(2,2,6,6-tetramethyl-4-piperidyl)·di(tridecyl)-1,2,3,4-butane tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)·di(tridecyl)-1,2,3,4-butane tetracarboxylate, bis(1,2,2,4,4-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-t-butyl-4-butyl) 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-t-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl 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-triazin-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-triazin-6-yl]aminoundecane, 1,6,11-tris[2,4-bis(N-butyl-N-(1,2,Examples of the hindered amine compounds include 2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-yl)aminoundecane. These may be used alone or in combination of two or more.

[0077] As the antistatic agent, cationic, anionic, nonionic, amphoteric, fatty acid partial esters such as glycerin fatty acid monoesters, and the like can be used. Specifically, alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, benzalkonium salts, N,N-bis(2-hydroxyethyl)-N-(3-dodecyloxy-2-hydroxypropyl)methyl ammonium methosulfate, (3-lauryl amidopropyl)trimethyl ammonium methyl sulfate, stearamidopropyl dimethyl-2-hydroxyethyl ammonium nitrate, stearamidopropyl dimethyl-2-hydroxyethyl ammonium phosphate, cationic polymers, alkyl sulfonates, alkyl benzene sulfonates, sodium alkyl diphenyl ether disulfonate, alkyl nitrate ester salts, phosphorus Acid alkyl ester salts, alkyl phosphate amine salts, stearic acid monoglyceride, pentaerythritol fatty acid esters, sorbitan monopalmitate, sorbitan monostearate, diglycerin fatty acid esters, alkyldiethanolamines, alkyldiethanolamine fatty acid monoesters, alkyldiethanolamides, polyoxyethylene dodecyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol monolaurates, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyether block copolymers, cetyl betaine, and hydroxyethyl imidazoline sulfate. These may be used alone or in combination of two or more.

[0078] As the filler, talc, calcium carbonate, barium sulfate, carbon fiber, mica, wollastonite, whisker, etc. can be used.

[0079] In this embodiment, the flame-retardant styrene-based resin composition may contain, in addition to the above-mentioned optional additive components, optional additive components such as an antiblocking agent, a colorant, an antiblooming agent, a surface treatment agent, an antibacterial agent, and an anti-viscosity agent (anti-viscosity agents such as the silicone oil described in JP 2009-120717 A, monoamide compounds of higher aliphatic carboxylic acids, and monoester compounds obtained by reacting higher aliphatic carboxylic acids with monohydric to trihydric alcohol compounds). In this embodiment, the total content of the above-mentioned optional additive components may be 0.05 to 5% by mass in the flame-retardant styrene-based resin composition.

[0080] The flame-retardant styrene-based resin composition of the present embodiment may consist essentially of only the components (A), (B), and (C).Also, the flame-retardant styrene-based resin composition may consist essentially of only the components (A), (B), (C), a dispersant, and optional additive components. The phrase "consisting essentially of only the components (A), (B), and (C)" means that the components (A), (B), and (C) account for 80 to 100 mass% (preferably 88 to 100 mass%) of the total amount (100 mass%) of the flame-retardant styrene-based resin composition. The phrase "consisting essentially of only the components (A), (B), (C), the dispersant, and any optional additional components" means that the components (A), (B), (C), the dispersant, and any optional additional components account for 95 to 100 mass% (preferably 98 to 100 mass%) of the total amount (100 mass%) of the flame-retardant styrene-based resin composition. The flame-retardant styrene-based resin composition of the present embodiment may contain inevitable impurities in addition to the components (A), (B), and (C), the dispersant, and any optional additional components, as long as the effects of the present invention are not impaired.

[0081] The flame-retardant styrene-based resin composition of this embodiment is formed from a flame-retardant styrene-based resin composition containing a predetermined amount of each of a styrene-based resin (A), a flame retardant (B) containing a phosphinate compound (b), glass balloons (C), and a dispersant and / or optional additional component added as needed. The materials or properties of the styrene-based resin (A), the flame retardant (B) containing a phosphinate compound (b), the glass balloons (C), and the dispersant and / or optional additional component added as needed, which are added to the flame-retardant styrene-based resin composition, are as described above. The amounts of the (A) component, the (B) component, the (C) component, the dispersant, and the optional additional component added can be appropriately adjusted and added so that the content in the flame-retardant styrene-based resin composition falls within the above range.

[0082] <Method for producing flame-retardant styrene-based resin composition> The flame-retardant styrene-based resin composition of the present embodiment can be produced by melt-kneading each component by any method. For example, a high-speed stirrer 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. can be used alone or in combination. The heating temperature during kneading is usually selected in the range of 180 to 260°C.

[0083] [Physical properties of flame-retardant styrene-based resin composition] <Flame retardancy> The flame retardancy of the flame-retardant styrene-based resin composition of the present embodiment is preferably within the standard in the UL94 vertical flame test (UL94-V test), i.e., flame retardancy class of V-0 to V-2. It is also preferable that the composition does not generate black smoke during combustion. In the present disclosure, flame retardancy and black smoke can be evaluated by the method described in the section [Examples] below.

[0084] <Linear expansion coefficient> The linear expansion coefficient of the molded body obtained from the flame-retardant styrene-based resin composition of the present embodiment is 6×10 -5 / °C or less, and more preferably 5×10 -5 / °C or less. The ratio of the linear expansion coefficient in the MD direction (flow direction during molding) to the TD direction (direction perpendicular to the MD direction) (TD / MD ratio) is preferably 0.8 to 1.3, and more preferably 0.9 to 1.2. The linear expansion coefficient is 6×10 -5 If the TD / MD ratio is greater than 1 / °C, the thermal expansion may cause defects in the product, or the metal may peel off in products that are bonded to metals. If the TD / MD ratio is outside the range, the product may warp due to heat. In this disclosure, the linear expansion coefficient is a value measured in accordance with the TMA method of JIS K7197. The dimensional accuracy of the molded product produced using the flame-retardant styrene-based resin composition of this embodiment is evaluated by the value of the linear expansion coefficient.

[0085] <Dielectric tangent> The dielectric loss tangent of the flame-retardant styrene-based resin composition of the present embodiment is 0.02 or less, and more preferably 0.01 or less. If the dielectric loss tangent is more than 0.02, the dielectric loss increases at high frequencies of 0.3 GHz or more, causing defects in the product. In this disclosure, the dielectric tangent is a value measured at 10 GHz in accordance with JIS C2138.

[0086] [Molded products] The flame-retardant styrene-based resin composition of the present embodiment can be used to produce a molded article by the above-mentioned melt kneading molding machine, or by using pellets of the obtained flame-retardant styrene-based resin composition as a raw material, through injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, or the like.

[0087] Molded articles containing the flame-retardant styrene-based resin composition of the present embodiment are preferably used for antenna substrates, printed circuit boards, injection molded articles (including injection compression), office automation equipment such as copiers, fax machines, televisions, radios, tape recorders, video decks, personal computers, printers, telephones, information terminals, refrigerators, and microwave ovens, home appliances, housings and various parts of electric and electronic devices, foamed insulation materials, insulating films, and the like. EXAMPLES

[0088] Hereinafter, the embodiments of the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to these examples in any way. <Measurement and evaluation methods> The physical properties of the resin compositions obtained in each of the Examples and Comparative Examples were measured and evaluated according to the following methods. (1) Flame retardancy evaluation (i) Burning class rating and burning time rating Using a test piece (b) (size: 127 mm × 12.7 mm, thickness: 1.5 mm) prepared by the method described below, flame retardancy was evaluated according to a method conforming to the UL94 vertical flame test (UL94-V test) using a test flame of 50 W. The flame of a gas burner was applied to the test piece (b) to evaluate the degree of combustion. The flame retardancy grade indicates the flame retardancy class as classified by the UL94-V test. The test was performed on five pieces for each test piece and the judgment was made. The 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 cotton dripping ignition V-1: Total burn time of 5 sticks is 250 seconds or less, maximum burn time is 30 seconds or less, no cotton dripping ignition V-2: Total burn time of 5 sticks is 250 seconds or less, maximum burn time is 30 seconds or less, cotton dripping may ignite Not V: Not compliant with UL94 (ii) Evaluation of black smoke during combustion In addition, the generation of black smoke during combustion was judged by visual inspection. If black smoke was generated during combustion, it was rated as ×, if only a small amount was generated, it was rated as △, and if almost no smoke was generated, it was rated as ◯.

[0089] (2) Linear expansion coefficient The linear expansion coefficient ( / °C) was measured in the MD and TD directions by cutting the center of the test piece (a) prepared by the method described below into a size of 10 × 5 × 4 mm in the MD and TD directions according to the TMA method (-30°C to 80°C) of JIS K7197.

[0090] (3) Dielectric tangent The dielectric loss tangent of the flame-retardant styrene-based resin was measured at 10 GHz using a PNA-L network analyzer N5230A (Agilent Technologies, Inc.) in accordance with JIS C2138.

[0091] (4) Content of rubber-like polymer (a) in rubber-modified styrene-based resin Taking into consideration the bonding mode of the butadiene segments, the amount of butadiene segments was measured using pyrolysis gas chromatography, and the content of the rubber-like polymer (a) was calculated from the amount of butadiene segments, expressed in mass %.

[0092] (5) Average particle size of rubber-like polymer particles (a) contained in rubber-modified styrene-based resin A 75 nm-thick ultrathin section was prepared from the rubber-modified styrene-based resin stained with osmium tetroxide, and three photographs were taken at a magnification of 10,000 times using an electron microscope. In the three photographs, the particles stained black are rubber-like polymer particles (a). From the photographs, the following formula (N1): Average particle diameter=ΣniDri 3 / ΣniDri 2 (N1) (In the formula, ni is the total number of rubber-like polymer particles (a) having a particle diameter Dri in three photographs, and the particle diameter Dri is the particle diameter calculated as a circle-equivalent diameter from the area of ​​the particles in the three photographs.) The area-average particle size was calculated from the above and was taken as the average particle size of the rubber-like polymer particles (a). In this measurement, the photograph was scanned at a resolution of 200 dpi and the measurement was performed using particle analysis software of an image analyzer IP-1000 (manufactured by Asahi Kasei Corporation).

[0093] (6) Contents of styrene monomer units, methacrylic acid monomer units, and methyl methacrylate monomer units in the styrene-based resin (a) Proton nuclear magnetic resonance ( 1 The resin composition was quantified from the integral ratio of the spectrum measured by a 1 H-NMR measuring device. Sample preparation: 30 mg of resin pellets were dissolved in 0.75 mL of d6-DMSO by heating at 60°C for 4 to 6 hours. ·Measuring equipment: JNM ECA-500 manufactured by JEOL Ltd. Measurement conditions: Measurement temperature 25℃, observation nucleus 1 H, accumulation count 64, repeat time 11 seconds.

[0094] (Spectral assignment) Regarding the assignment of the spectrum measured in dimethyl sulfoxide deuterated solvent, the peaks at 0.5 to 1.5 ppm are peaks derived from hydrogen of α-methyl group of methacrylic acid, methyl methacrylate, and six-membered cyclic acid anhydride, the peaks at 1.6 to 2.1 ppm are peaks derived from hydrogen of methylene group of polymer main chain, the peak at 3.5 ppm is peak derived from hydrogen of carboxylate ester (-COOCH3) of methyl methacrylate, and the peak at 12.4 ppm is peak derived from hydrogen of carboxylate of methacrylic acid. In addition, the peaks at 6.5 to 7.5 ppm are peaks derived from hydrogen of aromatic ring of styrene. Note that the content of six-membered cyclic acid anhydride is small in the resins of the present embodiment and the comparative example, so that quantification is usually difficult by this measurement method.

[0095] (7) Method for measuring the average particle size of the phosphinate compound (b) The method for measuring the average particle size of the granular phosphinate compound (b) is based on the volume-based particle size measured using a laser diffraction / scattering type particle size distribution measuring device. The value is measured using a 3% isopropanol aqueous solution as the dispersion medium of the phosphinate compound (b). Specifically, a laser diffraction / scattering type particle size distribution measuring device LA-910 (manufactured by Horiba, Ltd.) was used to perform a blank measurement using a 3% isopropanol aqueous solution as the dispersion medium, and then the measurement sample was placed so that the transmittance was the specified value (95% to 70%) and measured. The sample was dispersed in the dispersion medium by irradiating it with ultrasonic waves for 1 minute.

[0096] The materials used in the examples and comparative examples are as follows. [Styrene-based resin (A)] [GPPS-1] Polystyrene (GPPS, PS Japan, HF77) was used. [HIPS-1] A rubber-modified styrene-based resin, high impact polystyrene (HIPS), was used. The HIPS uses polybutadiene as a rubber-like polymer, and the analytical values ​​of the HIPS were that the content of the rubber-like polymer (a) was 12% by mass, and the average particle size of the rubber-like polymer (a) particles was 3.2 μm. [HIPS-2] A rubber-modified styrene-based resin, high impact polystyrene (HIPS), was used. The HIPS uses polybutadiene as the rubber-like polymer, and the analytical values ​​of the HIPS were that the content of the rubber-like polymer (a) was 7.5% by mass, and the average particle size of the rubber-like polymer (a) particles was 1.7 μm.

[0097] [Copolymer resin-1] A polymerization raw material composition liquid consisting of 70.0 parts by mass of styrene (ST), 15.0 parts by mass of butyl methacrylate (BA), 15.0 parts by mass of ethylbenzene, and 0.025 parts by mass of 1,1-bis(t-butylperoxy)cyclohexane was continuously fed at a rate of 1.1 L / hour to a 4-L complete mixing reactor, then to a polymerization apparatus consisting of a 2-L laminar flow reactor, and further to a devolatilizer connected to a single-screw extruder for removing volatile matters such as unreacted monomers and polymerization solvent, to prepare copolymer resin-1, which is a styrene-based copolymer resin. The polymerization reaction conditions in the polymerization step were a polymerization temperature of 122° C. in the complete mixing reactor and a polymerization temperature of 120 to 142° C. in the laminar flow reactor. The devolatilized unreacted gas was condensed in a condenser through which a coolant of −5° C. was passed, and recovered as an unreacted liquid. The polymer content in the final polymerization solution was measured after drying the polymerization solution at 215° C. under a reduced pressure of 2.5 kPa for 30 minutes according to the formula [(sample mass after drying / sample mass before drying)×100%], and was found to be 65.6% by mass.

[0098] [Flame retardant (B)] <Phosphinate compound (b)> Aluminum phosphinate (also referred to as DEP-B in Tables 1 and 2) "Exolit OP930 manufactured by Clariant Japan" Average particle size 3 μm Aluminum phosphinate (also referred to as DEP-A in Tables 1 and 2) "Exolit OP1230 manufactured by Clariant Japan" Average particle size: 20 μm Phosphate ester: Resorcinol bis-dixylenyl phosphate [manufactured by Daihachi Chemical Industry Co., Ltd., PX-200, melting point 92°C]

[0099] [Glass balloon (C)] Glass balloon-1: Glass Bubbles S4630 (manufactured by 3M Corporation, median diameter 19 μm, true density 0.46 g / cm 3 , compression strength 110.2MPa or more)

[0100] [Examples 1 to 6] The styrene resin (A), flame retardant (B) and glass balloon (C) having the composition ratio shown in Table 1 below were mixed in a total amount of 100 parts by mass, and 0.2 parts by mass of Irganox1076 and Irgafos168 were added and premixed. The resulting premixes were mixed together and melt-extruded at 180°C to 220°C using a twin-screw extruder (Toshiba Machine Co., Ltd., TEM-26SS), to obtain pellets of a flame-retardant styrene resin composition as a kneaded product. At this time, the screw rotation speed was 250 rpm and the discharge rate was 10 kg / hr. The pellet-shaped flame-retardant styrene-based resin composition thus obtained was molded using an injection molding machine manufactured by Japan Steel Works, Ltd. equipped with ISO527-2 multipurpose test piece type 1A at a cylinder temperature of 220°C, a mold temperature of 50°C, an injection pressure (gauge pressure 40-60MPa), an injection speed (panel set value) of 50%, and an injection time / cooling time of 5sec / 20sec to produce a test piece (a), and the physical properties were measured. In addition, a test piece (b) was produced under the same conditions as the above test piece (a) using a flat die with both ends gates measuring 127mm x 12.7mm x 1.5mm thick, and the flame retardancy was measured. The experimental results of Examples 1 to 6 are shown in Table 1.

[0101] [Comparative Examples 1 to 5] In Comparative Examples 1 to 5, styrene-based resin compositions were obtained in the same manner as in the Examples, except that the compositions were changed as shown in Table 2. Table 2 shows the results of measurement and evaluation of each physical property.

[0102] [Table 1]

[0103] [Table 2]

[0104] As shown in Table 1 above, the flame-retardant styrene-based resin compositions obtained in Examples 1 to 6 were excellent in low smoke generation and flame retardancy. In particular, it was confirmed that the respective properties were particularly improved when a specific rubber-modified styrene-based resin was used.

[0105] As shown in Table 2, low smoke generation, flame retardancy, dimensions, and low dielectric properties cannot be obtained with only the phosphinate compound (b). Furthermore, with only the glass balloons (C), not only is flame retardancy not obtained, but the destruction of the glass balloons (C) becomes large, so that TD / MD becomes large and low dielectric properties cannot be obtained. Furthermore, flame retardancy and low dielectric properties cannot be obtained with phosphorus-based flame retardants other than the phosphinate compound (b). Furthermore, if the amount of glass balloons (C) or the phosphinate compound (b) is more than the specified amount, the flowability is poor and molding is not possible. [Industrial Applicability]

[0106] The flame-retardant styrene-based resin composition of the present invention can be suitably used for electronic and electrical parts, printed circuit boards, antenna boards, automobiles, etc.

Claims

1. 40 to 94% by mass of a styrene-based resin (A), The following general formula (i): 【Chemical 1】 [In the above general formula (i), R ｉ１ and R ｉ２ are each independently unsubstituted or one or more hydrogen atoms are substituted by R ｉ３ represents 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 is represented by the following general formula (ii): 【Chemistry 2】 "In the above general formula (ii), R ｉｉ１ each independently represents 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 to another atom. M ｉ each independently represents at least one selected from the group consisting of a calcium ion, a magnesium ion, an aluminum ion, a zinc ion, a bismuth ion, a manganese ion, a sodium ion, a potassium ion, and a protonated nitrogen base; p ＋ is M ｉ represents an ionic valence of 1 to 3, and represents a positive integer of 1 to 3; m ｉ１ represents a positive integer from 1 to 3, n － represents a negative integer of −1, −2, or −3, r represents a positive integer of 1 to 3, provided that there are multiple M ｉ may be the same as or different from each other, |p ＋ ×r|=|n － ×m ｉ１ 3 to 30 mass % of a flame retardant (B) containing a phosphinate compound (b) represented by the formula: | and 3 to 30 mass % of glass balloons (C).

2. 2. The flame-retardant styrene-based resin composition according to claim 1, wherein the phosphinate compound (b) is at least one compound selected from the group consisting of phosphinates represented by the following general formula (1) and diphosphinates represented by the following general formula (2): 【Chemistry 3】 [In the above general formula (1), R １１ and R １２ each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; M １ represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen bases; ＋ is M １ represents an ionic valence of 1 to 3; m １ represents a positive integer from 1 to 3, and |a ＋ |=|m １ |It is. 【Chemistry 4】 [In the above general formula (2), R ２１ and R ２２ each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms; L ２３ represents 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 represents at least one selected from the group consisting of calcium ion, magnesium ion, aluminum ion, zinc ion, bismuth ion, manganese ion, sodium ion, potassium ion, and protonated nitrogen bases; b ＋ is M ２ represents an ionic valence of 1 to 3, and m ２ represents a positive integer of 1 to 3, q ​​represents a positive integer of 1 or 2, and |b ＋ ×q|=|2m ２ |It is.

3. 2. The flame-retardant styrene-based resin composition according to claim 1, wherein the styrene-based resin (A) is a rubber-modified styrene-based resin containing rubber-like polymer particles (a) containing a rubber-like polymer (a), the content of the rubber-like polymer (a) is 8 to 15 mass%, and the average particle size of the rubber-like polymer particles (a) is 2 to 4 μm.

4. 2. The flame-retardant styrene-based resin composition according to claim 1, wherein the glass bubbles (C) have an average particle size of 10 to 30 μm.

5. A molded article comprising the flame-retardant styrene-based resin composition according to any one of claims 1 to 4.

6. An antenna substrate comprising the flame-retardant styrene-based resin composition according to any one of claims 1 to 4.

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