JP2020066710A - Flame-retardant thermoplastic resin composition - Google Patents

Abstract

To provide a flame-retardant thermoplastic resin composition having moldability, heat resistance, rigidity, and high flame retardancy.SOLUTION: A flame-retardant thermoplastic resin composition contains a graft copolymer (A), a vinyl copolymer (B), a bromine flame retardant (C), an antimony compound (D), and a glass fiber (E) in a specific relationship.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flame-retardant thermoplastic resin composition having excellent flame retardancy, heat resistance, and moldability.

  Styrene-based resins represented by acrylonitrile-butadiene-styrene (ABS) resins have excellent moldability, but since they are easily combustible, it is necessary to add a flame retardant to impart flame retardancy. In addition, when high heat resistance and rigidity are required, such as an alternative application of metal parts, a method of adding high heat resistance and rigidity by adding an inorganic filler to a resin is generally used.

  As a method of making the ABS resin flame-retardant, there is a method of obtaining flame retardancy by using a halogen-based flame retardant and a flame retardant auxiliary agent typified by antimony oxide together. When higher heat resistance and rigidity are required, it is common to mix an inorganic filler such as glass fiber. Higher heat resistance and rigidity can be obtained by containing a large amount of glass fibers. However, the higher the glass fiber content is, for example, the judgment in the UL94 vertical flammability test stipulated by the UL (Underwriters Laboratories) standard in the United States. This leads to extending the glowing time (t3), which is one of the standards. The glowing time (t3) is the duration of the afterglow (flame, residual dust) observed after self-extinguishing of the first combustion and the second combustion. For example, as a criterion for the V-0 flame retardancy of UL94, the total (t2 + t3) of the second combustion time (t2) and the glowing time (t3) is defined to be within 30 seconds, and V-0 is achieved. Therefore, it is essential that the glowing time (t3) is at least 30 seconds or less. However, the present situation is that no method has been found for effectively reducing the glowing time (t3) in a resin composition reinforced with an inorganic filler such as glass fiber.

  For example, in Patent Document 1, an ABS resin, a styrene-N-phenylmaleimide-maleic anhydride copolymer, a flame retardant, an antimony compound is used as a thermoplastic resin composition having excellent heat resistance, flame retardancy, rigidity, and moldability. , A thermoplastic resin composition comprising hydrotalcites and glass fibers has been proposed.

  Further, Patent Document 2 proposes a fiber reinforced resin composition comprising an aromatic polycarbonate resin, a rubber-modified styrene resin, a glass fiber chopped strand, an organic halogen-containing flame retardant and an antimony compound.

  However, none of the thermoplastic resin compositions described in these patent documents have a good balance of heat resistance, rigidity and flame retardancy.

JP-A-7-53833 JP, 7-11100, A

  The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a flame-retardant thermoplastic resin composition having excellent heat resistance, rigidity and flame retardancy.

As a result of intensive studies to solve the above-mentioned problems, the present inventor substantially consists of specific materials, and the contents of those materials and the melt flow rate of the resin composition have a specific relationship. It was found that the above-mentioned problems can be solved by configuring the above. That is, it is the gist of the present invention that the contents are specified by the following descriptions (1) to (5).
(1) A graft copolymer obtained by graft-copolymerizing (A) a rubbery polymer (A) with an aromatic vinyl compound (A) and a vinyl cyanide compound (C), and having a grafting ratio of 15- Graft copolymer in which 50% by weight, and the weight ratio of the grafted portion derived from (A) and the grafted portion derived from (C) are (A) :( C) = 70: 30 to 80:20. ,
(B) a vinyl-based copolymer obtained by copolymerizing a vinyl-based monomer mixture containing an aromatic vinyl-based monomer (d) and a vinyl cyanide-based monomer (e),
(C) brominated flame retardant,
(D) an antimony compound, and
(E) A flame-retardant thermoplastic resin composition consisting essentially of glass fiber components, which is characterized by satisfying the following formulas 1 to 4. Composition.

α ≧ 20 (Formula 1)
39 ≦ (Q + 2R) ≦ 60 (Formula 2)
8 ≦ S ≦ 40 (Formula 3)
6 ≦ T ≦ 78 (Formula 4)
(Here, Q and R are mass fractions (parts by mass) of the component (C), and R is (D), when the total mass of the components (A) and (B) is 100 parts by mass. Represents the mass fraction (parts by mass) of the components, S is the proportion (mass%) of the (E) component in the total mass of the flame-retardant thermoplastic resin composition, and T is the flame-retardant thermoplastic resin composition. Represents the melt flow rate (g / 10 minutes) at 240 ° C./98 N. Further, α is a value calculated by the following mathematical formula 5.)

(2) As the component (B), (B-1) a vinyl-based copolymer having an intrinsic viscosity of 0.45 to 0.60 dL / g and (B-2) an intrinsic viscosity of 0.80 to 1.10 dL / g. The flame-retardant thermoplastic resin composition as described in (1) above, wherein the vinyl-based copolymer is used.
(3) The flame-retardant thermoplastic resin composition according to (1) or (2), wherein a brominated epoxy resin is used as the component (C).
(4) The flame-retardant thermoplastic resin composition according to (3), wherein the brominated epoxy resin has an epoxy equivalent of 500 to 6,000 g / eq.
(5) The flame-retardant thermoplastic resin composition according to any one of (1) to (4), wherein diantimony trioxide is used as the component (D).

  By using the flame-retardant thermoplastic resin composition of the present invention, a flame-retardant thermoplastic resin composition having excellent heat resistance, rigidity and flame retardancy can be obtained.

It is a graph showing the relationship between α and the glowing time (t3) obtained according to Equation 5 for the resin compositions prepared in Examples and Comparative Examples.

  Hereinafter, modes for carrying out the present invention will be specifically described.

  The flame-retardant thermoplastic resin composition of the present invention (hereinafter sometimes simply referred to as “resin composition”) is a graft copolymer (A), vinyl-based copolymer (B), bromine-based flame retardant. It consists essentially of (C), the antimony compound (D), and the glass fiber (E). Here, the term “substantially” means that other components may be contained to the extent that the effects of the invention are not impaired, and preferably the total amount of the components (A) to (E) in the resin composition is It is 95 mass% or more, more preferably 98 mass% or more, and most preferably 99 mass% or more. The upper limit is not particularly limited, but when it is not necessary to use other components, the total amount may be 100% by mass. Next, each of these components will be described.

<Graft copolymer (A)>
The graft copolymer (A) (component (A)) used in the present invention is obtained by graft-copolymerizing an aromatic vinyl compound (a) and a vinyl cyanide compound (c) on a rubbery polymer (a). It is a graft copolymer and has a grafting ratio of 15 to 50% by weight, and the weight ratio of the grafted portion derived from (a) and the grafted portion derived from (c) is (a) :( C) = 70: 30 to 80:20. By using such a graft copolymer (A), the toughness and impact resistance of the molded product can be improved.

  The grafting ratio (%) of the graft copolymer (A) is shown by the following formula. When the grafting ratio is determined, the sample is washed with a solvent such as acetone as necessary to remove ungrafted components before the measurement. The specific measuring method is as described in the section of Examples.

Grafting ratio (%) = {[amount of copolymer graft-polymerized on rubbery polymer] / [rubber content of graft copolymer]} × 100
Examples of the rubbery polymer (a) constituting the graft copolymer (A) include polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, styrene-butadiene block copolymer and butyl acrylate. A diene rubbery polymer such as a butadiene copolymer. The rubbery polymer (A) may be used alone or in combination of two or more. The glass transition temperature of the rubbery polymer (a) is preferably 0 ° C. or lower, and the lower limit is not particularly limited, but in practice, one having −80 ° C. or higher is used. Among the rubbery polymers exemplified above, polybutadiene is preferably used from the viewpoint of productivity and operability.

  The weight average particle diameter of the rubber polymer (a) is not particularly limited, but from the viewpoint of further improving the toughness and impact resistance of the molded product, it is preferably 0.10 μm or more, and 0.15 μm or more. Is more preferable. On the other hand, the weight average particle diameter of the rubbery polymer (A) is preferably 0.50 μm or less, and more preferably 0.40 μm or less, from the viewpoint of further improving the fluidity during molding. The weight average particle diameter of the rubbery polymer (a) is determined by the sodium alginate method (concentration of sodium alginate described in “Rubbaer Age Vol. 88 p. 484 to 490 (1960) by E. Schmidt, PH Biddison”). It is possible to measure the particle diameter at a cumulative weight fraction of 50% based on the amount ratio and the cumulative weight fraction of the sodium alginate concentration.).

  Examples of the aromatic vinyl compound (a) constituting the graft copolymer (A) include styrene, α-methylstyrene, vinyltoluene, o-ethylstyrene, p-methylstyrene, chlorostyrene and bromostyrene. Can be mentioned. The aromatic vinyl compound (a) may be used alone or in combination of two or more. Styrene is preferably used from the viewpoint of further improving the fluidity during molding.

  Examples of the vinyl cyanide compound (C) that constitutes the graft copolymer (A) include acrylonitrile, methacrylonitrile, and ethacrylonitrile. The vinyl cyanide compound (c) may be used alone or in combination of two or more. Among them, acrylonitrile is preferably used.

  The graft copolymer (A) used in the present invention may be graft-copolymerized with another copolymerizable monomer to the extent that the effects of the present invention are not lost. Other graft copolymerizable monomers include, for example, N-phenylmaleimide, N-methylmaleimide, and methyl methacrylate, which can be selected according to the respective purposes. One of the above-mentioned other copolymerizable monomers may be used, or two or more thereof may be used. For example, N-phenylmaleimide is preferably used in order to further improve heat resistance and flame retardancy. Moreover, in order to improve hardness, methyl methacrylate is preferably used.

  In the graft copolymer (A), the weight ratio of the part derived from the aromatic vinyl compound (a) and the part derived from the vinyl cyanide compound (c) is (a) :( c) = 70: 30 to. It is 80:20. Preferably, (a) :( c) = 71: 29 to 76:24. If the ratio of the portion derived from the aromatic vinyl compound (a) is too small, the fluidity at the time of molding process will be reduced. On the other hand, if the ratio of the portion derived from the aromatic vinyl compound (a) is too large, the toughness of the molded product will be reduced.

  In the flame-retardant thermoplastic resin composition of the present invention, the graft copolymer (A) may be used alone or in combination of two or more.

<Vinyl-based copolymer (B)>
The vinyl-based copolymer (B) (component (B)) used in the present invention is a vinyl-based monomer mixture containing an aromatic vinyl-based monomer (d) and a vinyl cyanide-based monomer (e). It is a copolymer obtained by copolymerization. By containing such a vinyl-based copolymer (B), the fluidity during molding can be improved.

  Examples of the aromatic vinyl-based monomer (d) constituting the vinyl-based copolymer (B) are those exemplified as the aromatic vinyl-based compound (a) constituting the above-mentioned graft copolymer (A). And styrene is particularly preferably adopted.

  Examples of the vinyl cyanide-based monomer (e) constituting the vinyl copolymer (B) include those exemplified as the vinyl cyanide compound (c) constituting the graft copolymer (A). Among them, acrylonitrile is particularly preferably used.

  Further, as the vinyl-based copolymer (B), other copolymerizable monomers may be used to the extent that the effects of the present invention are not lost. Examples of the other copolymerizable monomers include those exemplified as the other monomers that can be adopted in the graft copolymer (A).

  The weight ratio of the portion derived from the aromatic vinyl-based monomer (d) and the portion derived from the vinyl cyanide-based monomer (e) contained in the vinyl-based copolymer (B) is such that When the mass of (B) is 100% by mass, the portion derived from the aromatic vinyl-based monomer (d) is 60 to 85% by weight, and the vinyl cyanide-based monomer (e) is 15 to 40% by weight. Preferably there is.

  In the vinyl-based copolymer (B) used in the present invention, the intrinsic viscosity [η] at 30 ° C. of the vinyl-based copolymer (B) soluble in methyl ethyl ketone is not particularly limited.

  In addition, in the flame-retardant thermoplastic resin composition of the present invention, it is preferable to use a plurality of vinyl copolymers (B). Specifically, (B-1) intrinsic viscosity 0.45 to 0. The use of 60 dL / g vinyl-based copolymer and (B-2) vinyl-based copolymer having an intrinsic viscosity of 0.80 to 1.10 dL / g may be mentioned. By using such two kinds of vinyl-based copolymers, it is possible to easily adjust the intrinsic viscosity of the resin composition and α calculated by Formula 5.

  In the embodiment of the present invention, the graft copolymer (A) and the vinyl copolymer (B) may be produced, for example, by bulk polymerization, suspension polymerization, bulk suspension polymerization, solution polymerization, emulsion polymerization, precipitation. A polymerization method such as polymerization may be used. You may combine 2 or more types among the manufacturing methods mentioned above. The method of charging the monomers constituting each copolymer is not particularly limited, and the monomers may be charged all at once at the initial stage. Further, in order to adjust the composition distribution of the copolymer to a desired range, the monomers may be charged in several times.

  In the embodiment of the present invention, an initiator may be used when preparing the graft copolymer (A) and the vinyl copolymer (B). As the initiator, a peroxide or an azo compound is preferably used. A peroxide and an azo compound may be used in combination.

  Examples of the peroxide used as an initiator include benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diisopropylbenzene hydroperoxide, t-butyl hydroperoxide, t-butylcumyl peroxide, t-butyl. Peroxyacetate, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, di-t-butylperoxide, t-butylperoctate, 1,1-bis (t-butylperoxy) 3,3 , 5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxy-2-ethylhexanoate and the like. Two or more of the above-mentioned peroxides may be used. Among the above-mentioned peroxides, cumene hydroperoxide and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane are preferably used as the initiator.

  Examples of the azo compound used as an initiator include azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, and 2-cyano. -2-Propylazoformamide, 1,1'-azobiscyclohexane-1-carbonitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 1- Examples thereof include t-butylazo-1-cyanocyclohexane, 2-t-butylazo-2-cyanobutane, and 2-t-butylazo-2-cyano-4-methoxy-4-methylpentane. Two or more of the above-mentioned azo compounds may be used. Among the above-mentioned azo compounds, azobisisobutyronitrile is preferably used as the initiator.

  In producing the graft copolymer (A) and the vinyl copolymer (B), a chain transfer agent such as mercaptan or terpene may be used. By using a chain transfer agent, the degree of polymerization can be adjusted within a desired range. Specific examples of the chain transfer agent include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan and terpinolene. Two or more of the above chain transfer agents may be used. Among the above chain transfer agents, n-octyl mercaptan, t-dodecyl mercaptan and n-dodecyl mercaptan are preferably used.

<Brominated flame retardant (C)>
As the brominated flame retardant (C) (component (C)) used in the present invention, a flame retardant generally classified as a brominated flame retardant can be used, and a brominated epoxy resin, brominated polycarbonate resin, bromine can be used. Styrene resin, brominated polyphenylene ether (brominated polyphenylene oxide), and tetrabromobisphenol A are preferably used, and brominated epoxy resin is particularly preferably used. By using a brominated epoxy resin, flame retardancy can be improved without significantly impairing toughness and impact resistance. The bromine-based flame retardant (C) may be used alone or in combination of two or more.

  When using a brominated epoxy resin, its epoxy equivalent is preferably 500 to 6000 g / eq. If the epoxy equivalent is less than 500 g / eq, it may excessively react with the resin composition and gelation may occur during melt-kneading, and if it exceeds 6000 g / eq, the compatibility with the resin composition is poor. Therefore, the mechanical strength or flame retardancy may decrease.

  By containing the brominated flame retardant, it is possible to trap radical species generated during combustion of the molded product. Therefore, it is possible to suppress combustion and improve the flame retardancy of the molded product.

<Antimony compound (D)>
The flame-retardant thermoplastic resin composition of the present invention contains an antimony compound (D) (component (D)) together with the brominated flame retardant (C) described above, so that when the molded article is burned, The nonflammable gas resulting from the reaction between the flame retardant (C) and the antimony compound (D) can further improve the flame retardancy.

  As the antimony compound (D) used in the present invention, those generally classified as antimony compounds can be used. For example, antimony oxides such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate and the like can be used. Is mentioned. As the antimony compound (D), one type may be used, or two or more types may be used. Among the above antimony compounds (D), diantimony trioxide is particularly preferable, and by using diantimony trioxide, flame retardancy can be improved without significantly impairing toughness and impact resistance.

  The average particle size of the antimony compound (D) is preferably 0.01 μm or more and 10 μm or less. An antimony compound having such an average particle size can further improve the flame retardant effect.

<Glass fiber (E)>
The flame-retardant thermoplastic resin composition of the present invention can improve the heat resistance and rigidity of the molded product by containing the glass fiber (E) (component (E)). As the glass fiber (E), commercially available one can be used, and the average diameter of the glass fiber is preferably 0.3 to 20 μm and the average length is 0.1 to 10 mm, and the average diameter is 5 to 5. It is more preferable that the average length is 15 μm and the average length is 0.5 to 5 mm.

<Content of Each Component and Melt Flow Rate of Flame Retardant Thermoplastic Resin Composition>
The flame-retardant thermoplastic resin composition of the present invention satisfies the following formulas 1 to 4.

α ≧ 20 (Formula 1)
39 ≦ (Q + 2R) ≦ 60 (Formula 2)
8 ≦ S ≦ 40 (Formula 3)
6 ≦ T ≦ 78 (Formula 4)
(Here, Q and R are the mass fractions (parts by mass) of the component (C), and R is the above when the total mass of the components (A) and (B) is 100 parts by mass. D) represents the mass fraction (parts by mass) of the component, S is the proportion (mass%) of the component (E) in the total mass of the flame-retardant thermoplastic resin composition, and T is the flame-retardant thermoplastic resin. It represents the melt flow rate (g / 10 minutes) of the composition at 240 ° C./98 N. Further, α is a value calculated by the following mathematical formula 5.)

  In the resin composition of the present invention, the mass fraction (parts by mass) of the brominated flame retardant (C) when the total mass of the graft copolymer (A) and the vinyl copolymer (B) is 100 parts by mass. When Q is 2 parts by mass and the mass fraction of the antimony compound (D) is R + parts by mass, the flame retardancy of the resin composition is reduced when it is less than 39. On the other hand, when Q + 2R exceeds 60, the toughness and impact resistance of the molded product deteriorate.

  Further, when the proportion of the glass fiber (E) in the total mass of the flame-retardant thermoplastic resin composition is less than 8% by mass, the effect of improving rigidity and heat resistance is poor, and when it exceeds 40% by mass, the shrinkage rate of the molded product is low. As the ratio increases, the dimensional stability decreases and the molding processability also decreases.

  Further, if the melt flow rate (g / 10 minutes) of the flame-retardant thermoplastic resin composition of the present invention at 240 ° C / 98N is less than 6, moldability is impaired, and if it exceeds 78, dripping occurs during a combustion test. It is more likely to occur and impairs flame retardancy.

  Further, the flame-retardant thermoplastic resin composition of the present invention needs to have α of 20 or more, which is calculated by the following mathematical formula 5.

  Q, R, S and T are as previously described. The inventors of the present invention have made extensive studies and have obtained knowledge of factors that control the glowing time and their contributions, and have found that α obtained by Equation 5 has a high correlation with the glowing time.

  That is, as shown in FIG. 1, when α exceeds 20, the glowing time (t3), which is one of the judgment criteria in the UL94 vertical flammability test, can be reduced to 30 seconds or less, and α is about 45. It can be understood that it is possible to achieve the glowing time (t3) to zero by setting the value to be over. As can be understood from the formula (5), focusing on shortening the glowing time (t3), the brominated flame retardant and the antimony compound have a positive effect, and the glass fiber has a negative effect. It also has a negative effect on the melt flow rate.

  In the present invention, α is preferably less than 320, particularly preferably less than 80, from the viewpoint of maintaining physical properties and moldability.

  The flame-retardant thermoplastic resin composition of the present invention, as long as the performance of the present invention is not impaired, further hindered phenolic antioxidants, sulfur-containing compound antioxidants, copper iodide, potassium iodide, etc. Heat-resistant agents, phosphorus-containing organic compound-based antioxidants, phenol-based, acrylate-based, etc. thermal antioxidants, benzotriazole-based, benzophenone-based, succinate-based UV absorbers, antibacterial agents typified by silver-based antibacterial agents, It may contain an antifungal agent, carbon black, titanium oxide, a release agent, a lubricant, a pigment, a dye, an inorganic filler other than glass fiber, a flame retardant auxiliary agent such as a silicone type and a fluorine type.

  The flame-retardant thermoplastic resin composition of the present invention can be obtained, for example, by melt-kneading the constituent components. The melt-kneading method is not particularly limited, but, for example, a method of melt-kneading using a heating device, a cylinder having a vent, and a single or twin screw may be used. The heating temperature at the time of melt-kneading is usually selected from the range of 210 to 320 ° C. It is also possible to freely set the temperature gradient and the like during melt-kneading. When a biaxial screw is used, it may be either in the same rotation direction or in different rotation directions.

  The resin composition of the present invention can be formed into a molded product by subjecting it to a molding process. As a molding method, an injection molding method is preferable. The injection molding temperature is generally 200 to 300 ° C, and preferably 220 to 280 ° C, particularly preferably 230 to 270 ° C in the molding of the resin composition of the present invention. The temperature of the mold during injection molding is generally 30 to 80 ° C, preferably 40 to 80 ° C, and particularly preferably 50 to 80 ° C in molding the resin composition of the present invention. Is.

  The resin composition of the present invention can provide molded articles excellent in flame retardancy, heat resistance, and rigidity, and is therefore a housing for electric / electronic parts, automobile parts, machine mechanism parts, office automation equipment, household appliances, and the like. It can be used for various purposes such as parts. For example, various gears, various cases, sensors, LEP lamps, connectors, sockets, resistors, relay cases, switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed wiring boards. , Tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, housings, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, computer-related parts, etc. , VTR parts, TV parts such as TV frames, pedestals, back cabinets, irons, hair dryers, rice cooker parts, microwave oven parts, audio parts, audio / laser disk (registered trademark), compact discs Such as audio equipment parts, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, etc. household, office electrical product parts, office computer related parts, telephone related parts, facsimile related parts, copier related parts , Cleaning jigs, various bearings such as oilless bearings, stern bearings, underwater bearings, mechanical parts such as motor parts, lighters and typewriters, optical devices such as microscopes, binoculars, cameras and watches. , Parts for precision machinery, alternator terminal, alternator connector, IC regulator, various valves such as exhaust gas valve, fuel related / exhaust system / intake system various pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine cooling water joint, key Breather main body, carburetor spacer, exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crankshaft position sensor, air flow meter, air conditioner thermostat base, heating hot air flow control valve, Brush holders for radiator motors, water pump impellers, wiper motor related parts, debutors, starter switches, starter relays, wire harnesses for transmissions, window washer nozzles, air conditioner panel switch boards, coils for fuel-related electromagnetic valves, connectors for fuses, Horn terminal, electrical component insulation board, step motor rotor, lamp socket, lamp riff It is extremely useful for automotive parts such as lectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, igniter cases, gas range parts and dryer parts.

  The following examples are provided to describe the present invention more specifically, but these examples do not limit the present invention in any way. Here, "%" represents% by weight and "part" represents part by mass unless otherwise specified.

  First, the evaluation method in each Example and Comparative Example will be described below.

(1) Weight average particle diameter of rubbery polymer (A) The weight average particle diameter of the rubbery polymer (A) is "Rubber Age Vol. 88 p. 484-490 (1960) by E. Schmidt, P. It was determined by the sodium alginate method described in "H. Biddison". That is, by utilizing the fact that the polybutadiene particle size to be creamed varies depending on the concentration of sodium alginate, the particle size was calculated as a cumulative weight fraction of 50% from the cumulative weight fraction of the creamed weight ratio and the sodium alginate concentration.

(2) Grafting Rate of Graft Copolymer (A) 200 ml of acetone was added to a predetermined amount (m; about 1 g) of the graft copolymer, and the mixture was refluxed for 3 hours in a water bath at 70 ° C. This solution was added at 8800 r. p. m. After centrifugation at (10000 G) for 40 minutes, the insoluble matter was filtered. The insoluble matter was dried under reduced pressure at a temperature of 60 ° C. for 5 hours, and the weight (n (g)) was measured. The graft ratio was calculated by the following formula. Here, L is the rubber content of the graft copolymer.
Grafting rate (%) = {[(n)-((m) × L)] / [(m) × L]} × 100.

(3) Flame retardancy Flame retardance was evaluated according to UL94 standard defined by UL (Underwriters Laboratories) in the United States. The resin composition was used as a test piece for flame retardancy evaluation having a thickness of 1.5 mm, and after being left at 23 ° C. and 50% relative humidity for 48 hours, the upper end of the test piece was vertically fixed with a clamp, and the test piece was attached to the lower end of the test piece. After applying a predetermined flame for 10 seconds, the first burning time (t1) of the test piece from the time when the flame was released was measured. After confirming the extinction of the test piece, immediately after the predetermined flame was again applied to the lower end of the test piece for 10 seconds, the second burning time (t2) of the test piece from the time when the flame was released was measured. Further, the time (t3) of the glowing (afterglow, residual dust, fire) that occurs at the same time as the end of the second combustion was measured. This measurement was repeated for five test pieces, and a total of 15 pieces of data of 5 pieces of first burning time (t1) data, 5 pieces of second burning time (t2) data and 5 pieces of glowing time (t3) data were obtained. First burning time and second burning time The total burning time of 10 data is 50 seconds or less, the maximum burning time of 10 data is 10 seconds or less, and the test piece is clamped. It did not burn up, and the flamed melt did not drip and ignite the gauze 12 inches below, and the second burning time (t2) and glowing time (t3) for all five test pieces. If the sum of the above was within 30 seconds, it was evaluated as V-0 equivalent. As for the evaluation results, those which passed the V-0 standard were judged to be "V-0", and those which did not pass the V-0 standard were judged to be "NG".

(4) Glowing time The largest value was used from the total of 5 pieces of glowing time (t3) data obtained in the flame retardancy evaluation.

(5) Deflection temperature under load (heat resistance)
A test piece for measuring the deflection temperature under load having a thickness of 4.0 mm obtained by using the resin composition was conditioned for 24 hours in a desiccator at 23 ° C. and a relative humidity of less than 15% in accordance with the regulations of ISO75 (2004). The deflection temperature under load was measured under the condition of a load of 1.8 MPa in the dried test piece subjected to the above.

(6) Melt flow rate (fluidity)
The pellets of the resin composition were dried in a hot air dryer at 80 ° C. for 5 hours or more, and then the melt flow rate (g / 10 minutes) was measured under the conditions of 240 ° C. and 98 N according to ISO1133 (2005). did.

(7) Flexural modulus (rigidity)
Regarding a test piece for rigidity evaluation produced by using a resin composition, a test piece that was conditioned for 24 hours in an atmosphere of 23 ° C. and 50% relative humidity in accordance with the regulations of ISO178 (2004) was bent. A characteristic test was carried out to measure the flexural modulus.

  Next, the raw materials used in Examples and Comparative Examples will be described.

[Production of Graft Copolymer (A)]
In a reactor purged with nitrogen, 120 parts by weight of pure water, 0.5 parts by weight of glucose, 0.5 parts by weight of sodium pyrophosphate, 0.005 parts by weight of ferrous sulfate and polybutadiene latex (weight average particle diameter 0.3 μm, 60 parts by weight (gel content 85%) (solid content conversion) was charged, and the temperature in the reactor was raised to 65 ° C while stirring. When the internal temperature reached 65 ° C, polymerization was started, and a mixture of 30 parts by weight of styrene, 10 parts by weight of acrylonitrile and 0.3 part by weight of t-dodecylmercaptan was continuously added dropwise over 5 hours. At the same time, an aqueous solution containing 0.25 parts by weight of cumene hydroperoxide, 2.5 parts by weight of potassium oleate and 25 parts by weight of pure water was continuously added dropwise over 7 hours to complete the reaction. The resulting styrene copolymer latex was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered and dried to obtain a graft copolymer (A). The graft ratio of this graft copolymer (A) was 38%, and the intrinsic viscosity of the acetone-soluble component was 0.33 dl / g.

[Production of Vinyl Copolymer (B-1)]
Using a continuous bulk polymerization apparatus consisting of a preheater and a demonomer, a monomer mixture consisting of 72% by weight of styrene and 28% by weight of acrylonitrile was continuously bulk polymerized at 135 kg / hour. In the polymerization reaction mixture, unreacted monomers were evaporated and collected from the vent port under reduced pressure using a single-screw extruder type demonomer, while a vinyl-based copolymer (B-1) was obtained from the demonomer. The intrinsic viscosity of the obtained vinyl copolymer (B-1) was 0.53 dl / g. The average content of the structural units derived from the vinyl cyanide-based monomer (e) was 26% by weight, and the content of the structural units derived from the vinyl cyanide-based monomer (e) was 2% higher than the average content. The proportion of copolymers higher by weight% or more was 0% by weight.

[Production of Vinyl Copolymer (B-2)]
80 parts by mass of acrylamide, 20 parts by mass of methyl methacrylate, 0.3 parts by mass of potassium persulfate, and 1800 parts by mass of ion-exchanged water were charged into a reactor, and the gas phase in the reactor was replaced with nitrogen gas and mixed well. While keeping at 70 ° C. The reaction was continued until the monomer was completely added to the polymer to obtain an aqueous solution of acrylamide and a methyl methacrylate binary copolymer. The obtained aqueous solution was a slightly cloudy and viscous aqueous solution. To the obtained aqueous solution, 35 parts by mass of sodium hydroxide and ion-exchanged water were added to maintain alkaline as a 0.6% acrylamide / methyl methacrylate binary copolymer aqueous solution, and the mixture was stirred at 70 ° C. for 2 hours. . After stirring, the aqueous solution of the binary copolymer was cooled to room temperature to obtain a transparent aqueous solution of methyl methacrylate-acrylamide copolymer for suspension polymerization.

  A 20 L autoclave was charged with 6 parts by mass of an aqueous solution of the methyl methacrylate-acrylamide copolymer obtained by the above method, stirred at 400 rpm, and the system was replaced with nitrogen gas. Next, a monomer mixture of 29 parts by mass of acrylonitrile, 11 parts by mass of styrene, 0.35 parts by mass of azobisisobutyronitrile, 0.063 parts by mass of t-dodecylmercaptan, and 0.094 parts by mass of n-octylmercaptan. Was added over 30 minutes while stirring the reaction system, and the copolymerization reaction was started at 70 ° C. After starting the copolymerization reaction, the temperature was raised to 110 ° C. over 180 minutes. 60 parts by mass of styrene was added between 50 and 120 minutes after the initiation of the copolymer reaction. After reaching 110 ° C., the temperature was kept at 110 ° C. for 30 minutes, followed by cooling, polymer separation, washing and drying to obtain a vinyl copolymer (B-2). The intrinsic viscosity of the vinyl copolymer (B-2) measured with a methyl ethyl ketone solvent (temperature: 30 ° C.) was 0.95 dl / g.

[Brominated flame retardant (C)]
A brominated epoxy resin “Prasam EP-20 (epoxy equivalent 984 g / eq)” manufactured by DIC Corporation was used.

[Antimony compound (D)]
Antimony trioxide “PATOX M (purity 99% or more, average particle size 0.5 μm)” manufactured by Nippon Seiko Co., Ltd. was used.

[Glass fiber (E)]
Glass fiber ECS03T-351 (average diameter 13 μm, average length 3 mm) manufactured by Nippon Electric Glass Co., Ltd. was used.

  Hereinafter, examples and comparative examples will be described.

Examples 1-11, Comparative Examples 1-8
The graft copolymer (A), vinyl-based copolymer (B), bromine-based flame retardant (C), antimony compound (D) and glass fiber (E) described above are used in mass parts shown in Table 1 or Table 2. And melted and kneaded using a vented single-screw extruder with a screw diameter of 40 mm (FS40 manufactured by Ikegai Co., Ltd.) at a cylinder set temperature of 230 ° C. and a screw rotation speed of 80 rpm to obtain pellets of the resin composition. It was

  The results of evaluation of each physical property are shown in Table 1 or Table 2. The relationship between α of the obtained resin composition and glowing time is shown in FIG. It can be understood that these have a high correlation.

  From Table 1, it can be seen that the flame-retardant thermoplastic resin compositions (Examples 1 to 11) according to the embodiment of the present invention are excellent in balance of flame retardancy, rigidity and heat resistance.

On the other hand, in all of Comparative Examples 1 to 7, α was smaller than 20, the glowing time (t3) exceeded 30 seconds, and the flame retardancy was insufficient.

Claims (5)

(A) A graft copolymer in which an aromatic vinyl compound (a) and a vinyl cyanide compound (c) are graft-copolymerized with a rubbery polymer (a), and the grafting ratio is 15 to 50% by weight. A graft copolymer in which the weight ratio of the grafted portion derived from (i) and the grafted portion derived from (u) is (i) :( u) = 70: 30 to 80:20,
(B) a vinyl-based copolymer obtained by copolymerizing a vinyl-based monomer mixture containing an aromatic vinyl-based monomer (d) and a vinyl cyanide-based monomer (e),
(C) brominated flame retardant,
(D) an antimony compound, and
(E) A flame-retardant thermoplastic resin composition consisting essentially of glass fiber components, which satisfies the following formulas 1 to 4.
α ≧ 20 (Formula 1)
39 ≦ (Q + 2R) ≦ 60 (Formula 2)
8 ≦ S ≦ 40 (Formula 3)
6 ≦ T ≦ 78 (Formula 4)
(Here, Q and R are the mass fractions (parts by mass) of the component (C), and R is the above when the total mass of the components (A) and (B) is 100 parts by mass. D) represents the mass fraction (parts by mass) of the component, S is the proportion (mass%) of the component (E) in the total mass of the flame-retardant thermoplastic resin composition, and T is the flame-retardant thermoplastic resin. It represents the melt flow rate (g / 10 minutes) of the composition at 240 ° C./98 N. Further, α is a value calculated by the following mathematical formula 5.)

As the component (B), (B-1) a vinyl-based copolymer having an intrinsic viscosity of 0.45 to 0.60 dL / g and (B-2) a vinyl-based copolymer having an intrinsic viscosity of 0.80 to 1.10 dL / g. The flame-retardant thermoplastic resin composition according to claim 1, which comprises a copolymer. The flame-retardant thermoplastic resin composition according to claim 1, wherein a brominated epoxy resin is used as the component (C). The flame-retardant thermoplastic resin composition according to claim 3, wherein the epoxy equivalent of the brominated epoxy resin is 500 to 6,000 g / eq. The flame-retardant thermoplastic resin composition according to claim 1, wherein diantimony trioxide is used as the component (D).

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