JP2013159650A - Styrene-based flame retardant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrene-based flame retardant resin composition keeping fixed flame retardancy without using antimony trioxide having large environmental risk, low in cost as a composition using an inorganic compound and provided with surface impact strength practically required for OA equipment or home appliances.SOLUTION: A styrene-based flame retardant resin composition contains (B) 26-39 pts.mass bromine-based flame retardant, (C) 3-7 pts.mass tin oxide and (D) 1-6 pts.mass talc in (A) 100 pts.mass rubber-modified polystyrene resin.

Description

The present invention relates to the provision of a styrene-based flame-retardant resin composition that has little environmental concern, maintains a certain level of flame retardancy, and has surface impact strength that is practically necessary for OA equipment and home appliances.

Styrenic resins are used in a wide range of applications by taking advantage of their properties. Among these, flame retardant resins imparted with a high degree of flame retardancy are used in various fields including OA equipment such as personal computers, printers and copiers, and home appliances such as TVs and audios.

Halogen-containing compounds are used for flame-retarding styrene-based resins, and a method of adding a flame-retardant aid such as antimony trioxide as required is generally employed. However, since antimony trioxide is designated as a deleterious substance, it has been suggested that it has an impact on the environment instead of obtaining flame retardancy, and there is a demand for the development of a flame retardant resin composition that does not use antimony trioxide. Yes.

Styrenic flame retardant resin composition that does not use antimony trioxide, a styrene resin comprising a small amount of impact modifier (styrene-butadiene-styrene), polyolefin, halogen-containing flame retardant and inorganic flame retardant synergist in styrene resin A flame retardant resin composition is disclosed, and iron oxide, tin oxide, zinc oxide, aluminum trioxide, antimony trioxide, antimony pentoxide, bismuth oxide, molybdenum trioxide, tungsten trioxide, zinc borate as inorganic flame retardant synergists Etc. are illustrated. However, only antimony trioxide is used in the examples (see Patent Document 1). There is also a flame retardant resin composition that is used in combination with tin oxide and nickel oxide as a flame retardant aid in a styrene resin. (For example, see Patent Document 2)

Special Table 2000-500182 JP-A-9-59461

However, as an alternative material when antimony trioxide is not used in any case, an expensive inorganic compound is used, so that the cost as a composition may be increased.

The object of the present invention is a composition that does not use antimony trioxide, which is of great concern for the environment, at low cost, maintaining a certain level of flame retardancy, and having surface impact strength that is practically necessary for OA equipment and home appliances. Another object of the present invention is to provide a styrene-based flame retardant resin composition.

As a result of earnest research to solve these problems, the present inventor (A) blended a brominated flame retardant, further tin oxide and talc with the rubber-modified polystyrene resin, thereby improving the rubber-modified polystyrene resin. As a result, the present inventors have found a resin composition having high flame retardancy while maintaining the above properties.

That is, the present invention is as follows.

1. (A) To 100 parts by mass of rubber-modified polystyrene resin, (B) 26 to 39 parts by mass of brominated flame retardant, (C) 3 to 7 parts by mass of tin oxide, and (D) 1 to 6 parts by mass of talc A styrene-based flame retardant resin composition characterized by comprising:
2. (A) The styrenic flame retardant resin composition as described in 1 above, wherein the reduced viscosity of the matrix portion of the rubber-modified polystyrene resin is 0.55 to 0.85 dl / g and the rubber content is 4 to 15% by mass.
3. (B) The styrene-based flame retardant resin composition as described in 1 or 2 above, wherein the brominated flame retardant is 2,4,6-tris (2,4,6-tribromophenoxy) -1,3,5-triazine. object.
4). (C) The styrene-based flame retardant resin composition according to any one of 1 to 3, wherein the tin oxide is stannic oxide.
5. (C) The styrene-based flame retardant resin composition as described in 4 above, wherein the median diameter is 10 μm or less when the particle size distribution of tin oxide is measured with a laser diffraction / scattering particle size distribution analyzer.
6). (C) The styrene-based flame retardant resin composition as described in 4 above, wherein the median diameter when the particle size distribution of tin oxide is measured with a laser diffraction / scattering particle size distribution analyzer is 4 μm or less.

The styrene-based flame retardant resin composition of the present invention is a composition that does not use antimony trioxide of great environmental concern at low cost, maintains a certain level of flame retardancy, and is practical in OA equipment and home appliances. It has excellent flame resistance and physical property balance with the required surface impact strength. Therefore, the styrene-based flame retardant resin composition of the present invention can be effectively used in OA equipment and home appliances.

Below, the styrene-type flame retardant resin composition of this invention is demonstrated in detail. The rubber-modified polystyrene resin used in the present invention is an aromatic vinyl monomer, for example, a rubber-like polymer dissolved in a mixture of a styrene monomer and an inert solvent, and stirred to perform bulk polymerization or suspension polymerization. An aromatic vinyl monomer polymer obtained by solution polymerization or the like, for example, a polymer in which a rubber-like polymer is dispersed in a styrene polymer matrix. The rubber-modified polystyrene resin (A) may be a mixture obtained by mixing a polymer of an aromatic vinyl monomer obtained separately, for example, a styrene polymer.

The molecular weight of the matrix portion is not particularly limited, but the reduced viscosity (ηsp / C) is 0.50 dl / g or more, preferably 0.55 to 0.85 dl / g. The reduced viscosity was measured with a toluene solution having a polymer concentration of 0.4% (mass / volume) at a temperature of 30 ° C. using an Ubbelohde viscometer. If the reduced viscosity exceeds 0.85 dl / g, the fluidity of the composition will be low, so that it will be difficult to mold, and if it is less than 0.50 dl / g, it will be difficult to exhibit practically sufficient strength. There's a problem. Although there is no restriction | limiting in particular about rubber | gum content, As a rubber modified styrene resin, 4-15 mass% generally used is suitable. The rubber content is preferably determined in consideration of the balance between impact strength and rigidity necessary for the molded product.

Examples of the aromatic vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and the like. Among these, styrene is preferable, and these monomers can be used in combination. Examples of the rubbery polymer include polybutadiene rubber, styrene / butadiene copolymer, styrene / butadiene / styrene block copolymer, and among them, polybutadiene is preferable.

The (B) brominated flame retardant used in the present invention is one generally used in this field. For example, tetrabromobisphenol A, tetrabromobisphenol A derivatives, decabromodiphenyl ether, ethylenebistetrabromophthalimide , Hexabromocyclododecane, 1,2-bis (pentabromophenyl) ethane, bis (2,4,6-tribromophenoxy) ethane, 2,4,6-tris (2,4,6-tribromophenyl) -1,3,5-triazine and the like. Among these, 2,4,6-tris (2,4,6-tribromophenyl) -1,3,5-triazine is preferably used.

These compounds can be used alone or in combination. The blending ratio of the brominated flame retardant with respect to 100 parts by mass of the rubber-modified polystyrene resin is preferably 26 to 39 parts by mass. If it is less than 26 parts by mass, the flame retardancy is not sufficient, and if it exceeds 39 parts by mass, the flame retardancy is improved, but the surface impact strength is reduced and the cost is increased, which is not suitable.

Examples of the tin oxide (C) used in the present invention include stannous oxide and stannic oxide, but stannic oxide is also preferable from the viewpoint of flame retardancy. Further, the tin oxide preferably has a median diameter of 10 μm or less as measured by a laser diffraction / scattering particle size distribution analyzer. A median diameter of 4 μm or less is more preferable. When it exceeds 10 μm, flame retardancy and surface impact strength are reduced. The blending ratio of tin oxide to 100 parts by mass of the rubber-modified polystyrene resin is preferably 3 to 7 parts by mass. If it is less than 3 parts by mass, the flame retardancy is insufficient, and if it exceeds 7 parts by mass, the surface impact strength is lowered, and the cost is not preferred.

The blending ratio of (D) talc used in the present invention is 1 to 6 parts by mass with respect to 100 parts by mass of the rubber-modified polystyrene resin. If the amount is less than 1 part by mass, the effect of improving flame retardancy is not obtained.

In the styrene-based flame-retardant resin composition of the present invention, preferable ranges in terms of flame retardancy, surface impact strength, balance of these properties, cost, and the like are (A) 100 parts by mass of the rubber-modified polystyrene resin, (B) It is a blending ratio containing 26 to 39 parts by mass of a brominated flame retardant, (C) 3 to 7 parts by mass of tin oxide, and (D) 1 to 6 parts by mass of talc.

Furthermore, when high flame retardancy is required, (A) 100 parts by mass of rubber-modified polystyrene resin, (B) 26 to 39 parts by mass of brominated flame retardant, (C) 4 to 7 parts by mass of tin oxide, And (D) It is preferable that the blending ratio contains 1 to 6 parts by mass of talc because V-1 in the vertical combustion test method of Subject No. 94 of US Underwriters Laboratories (UL) is satisfied. Further, (A) 100 parts by mass of rubber-modified polystyrene resin contains (B) 29 to 39 parts by mass of a brominated flame retardant, (C) 4 to 7 parts by mass of tin oxide, and (D) 1 to 6 parts by mass of talc. The blending ratio is more preferable because a higher flame retardancy level V-0 is satisfied.

The styrene-based flame retardant resin composition of the present invention includes other additives such as a plasticizer, a solvent, a stabilizer, an ultraviolet absorber, a filler, a colorant, and a reinforcing agent as long as the object of the present invention is not impaired. Etc. can be added.

A known mixing technique can be applied to the method for mixing the styrene-based flame retardant resin composition of the present invention. For example, a uniform styrene-based flame retardant resin composition is obtained by further melt-kneading a mixture preliminarily mixed with a mixing apparatus such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer. I can do it. There is no particular limitation on melt kneading, and a known melting technique can be applied. Suitable melt kneaders include Banbury mixers, kneaders, rolls, single screw extruders, special single screw extruders, and twin screw extruders. Furthermore, there is a method of separately adding an additive such as a flame retardant from the middle of a melt-kneading apparatus such as an extruder.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The rubber-modified polystyrene resins used in Examples and Comparative Examples were mixed with H830, H800 and G320 manufactured by Toyo Styrene Co., Ltd., and the reduced viscosity of polystyrene in the matrix portion was 0.7 dl / g, and the rubbery polymer content was 7 A composition having a composition of 1% by mass was prepared and used. In Tables 1 to 4 described later, the rubber-modified polystyrene resin obtained here was abbreviated as HI-PS.

The reduced viscosity (ηsp / C) of the rubber-modified polystyrene resin was measured by adding a mixed solvent of 15 ml of methyl ethyl ketone and 15 ml of acetone to 1 g of the rubber-modified polystyrene resin obtained above, and dissolving by shaking for 2 hours at a temperature of 25 ° C. The insoluble matter was settled by separation, the supernatant was taken out by decantation, 500 ml of methanol was added to precipitate the resin, and the insoluble matter was filtered and dried. The resin component obtained by the same operation was dissolved in toluene to prepare a sample solution having a polymer concentration of 0.4% (mass / volume). This sample solution and pure toluene were measured at a constant temperature of 30 ° C. using a Ubbelohde viscometer, and the number of seconds during which the solution flowed was measured.
ηsp / C = (t1 / t0-1) / C
t0: Pure toluene flow down seconds
t1: Sample solution flow down seconds
C: Polymer concentration

The rubber-like polymer content was measured by dissolving a rubber-modified styrene resin in chloroform, adding a certain amount of iodine monochloride / carbon tetrachloride solution and leaving it in the dark for about 1 hour, then 15% (mass / volume). A potassium iodide solution and 50 ml of pure water were added, and excess iodine monochloride was titrated with a 0.1N sodium thiosulfate / ethanol aqueous solution and calculated from the amount of iodine monochloride added.

(B) For brominated flame retardants, trade name Piroguard SR245 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., which is 2,4,6-tris (2,4,6-tribromophenoxy) -1,3,5-triazine, is used. used. Moreover, the brand name SAYTEX8010 by the Albemarle company which is 1,2-bis (pentabromophenyl) ethane was used.

(C) For the tin oxide, trade name SH (median diameter is 4 μm), which is stannic oxide manufactured by Nippon Chemical Industry Co., Ltd., and stannic oxide having a median diameter of 10 μm is airflow manufactured by Seishin Enterprise Co., Ltd. It was produced by classifying stannic oxide manufactured by Nippon Chemical Industry Co., Ltd. with a sieving machine.

For measuring the median diameter, a laser diffraction scattering type particle size distribution measuring instrument manufactured by Seishin Enterprise Co., Ltd. was used.

(D) The product name KP talc manufactured by Fuji Talc was used as the talc.

Next, a method for mixing the styrene-based flame retardant resin composition of the present invention will be described. (A) Rubber-modified polystyrene resin, (B) Brominated flame retardant, (C) Tin oxide, and (D) Talc are blended in the amounts shown in Tables 1 to 4, and all of these components are added to a Henschel mixer (Mitsui Miike Chemical Industries). FM20B) and supplied to a twin-screw extruder (Toshiki Machine Co., Ltd., TEM26SS) to form a strand, which was cooled with water and led to a pelletizer to be pelletized. At this time, the cylinder temperature was 230 ° C. and the supply amount was 30 kg / hour.

Various measurements shown in Examples and Comparative Examples were performed by the following methods.

The flame retardance was measured in accordance with the vertical combustion test method of Subject No. 94 of US Underwriters Laboratories (UL), and the flammability of a specimen having a thickness of 1.5 mm was evaluated. In addition, NG in a table | surface shows what does not satisfy any of V-2, V-1, and V-0.

The test piece for the combustion test was molded at a cylinder temperature of 170 ° C. with an injection molding machine (Toshiba, IS80EP).

The surface impact strength was measured in accordance with JIS K 7211-1 puncture impact test. The test piece used was a 90 mm square plate with a thickness of 2 mm, and the weight tip shape was 10 mm in diameter. A 50% fracture energy of 0.3J or higher was accepted and less than 0.3J was rejected.

The results are shown in Tables 1 to 4 above.
From the examples in Table 1 and Table 2, it can be seen that the styrene flame retardant resin composition of the present invention has improved flame retardancy and surface impact strength in a well-balanced manner.

However, in the styrene-based flame retardant resin compositions obtained in the comparative examples of Table 3 and Table 4 that do not satisfy the provisions of the present invention, both the flame retardancy and the surface impact strength are excellent, but both It can be seen that the characteristics are not excellent.

For example, in the case where tin oxide (C) is not added, even if a specified amount of talc (D) is added, flame retardancy is less than V-2 level in the UL94 vertical combustion test (Comparative Example 1 and Comparative Example 2). . Moreover, even if talc (D) is present in a specified amount or tin oxide (C) is added, if the added amount is less than the specified amount, the flame retardancy does not reach the V-2 level (Comparative Example 3). On the contrary, if tin oxide (C) is added more than the specified amount, the flame retardancy reaches V-0, but the surface impact strength is lowered (Comparative Example 4). Even when tin oxide (C) is present in a specified amount, if talc (D) is not added, that is, if the amount of talc (D) is less than the specified amount, flame retardancy does not reach the V-2 level (comparison) On the other hand, if talc (D) is added in excess of the specified amount, flame retardancy reaches V-0, but it is not preferable because the surface impact strength is reduced (Comparative Example 6). Furthermore, even if tin oxide (C) and talc (D) are added in specified amounts, if the amount of brominated flame retardant (B) added is less than the specified amount, the flame retardancy will not reach the V-2 level (comparison) Example 7), and too much, is not preferable because the surface impact strength is lowered (Comparative Example 8).

Claims (6)

(A) To 100 parts by mass of rubber-modified polystyrene resin, (B) 26 to 39 parts by mass of brominated flame retardant, (C) 3 to 7 parts by mass of tin oxide, and (D) 1 to 6 parts by mass of talc A styrene-based flame retardant resin composition characterized by comprising: (A) The styrene flame-retardant resin composition according to claim 1, wherein the reduced viscosity of the matrix portion of the rubber-modified polystyrene resin is 0.55 to 0.85 dl / g and the rubber content is 4 to 15% by mass. object. (B) The styrenic flame retardant according to claim 1 or 2, wherein the brominated flame retardant is 2,4,6-tris (2,4,6-tribromophenoxy) -1,3,5-triazine. A flammable resin composition. The styrenic flame retardant resin composition according to any one of claims 1 to 3, wherein (C) tin oxide is stannic oxide. (C) The styrene flame-retardant resin composition according to claim 4, wherein the median diameter when the particle size distribution of tin oxide is measured with a laser diffraction / scattering particle size distribution analyzer is 10 μm or less. (C) The styrene flame-retardant resin composition according to claim 4, wherein the median diameter when the particle size distribution of tin oxide is measured by a laser diffraction / scattering particle size distribution analyzer is 4 μm or less.