JP6440972B2 - Styrene flame-retardant resin composition and molded article using the same - Google Patents

Description

  The present invention relates to a styrene-based flame retardant resin composition containing a brominated flame retardant, and a molded article formed using the same, and more specifically, has high flame resistance and impact strength, and the addition of a brominated flame retardant The present invention relates to a styrene-based flame retardant resin composition and a molded body whose amount is reduced.

  Styrenic resins are used in a wide range of applications by taking advantage of their properties. Among them, flame retardant resins imparted with high flame resistance are used in various fields including office automation equipment such as word processors, personal computers, printers, copiers, and home appliances such as TVs, VTRs, and audio. .

  In recent years, hot runner molding method using a large molding machine, gas assist injection method, and the like are applied in the fields of OA equipment and home appliances in order to cope with the increase in size of plastic parts. For this reason, the resin used is required to have excellent moldability in addition to flame retardancy, and in addition, light resistance is also regarded as important because it is exposed to fluorescent light and light entering from outside.

  Patent Document 1 discloses a highly flame retardant by combining a halogenated bisimide flame retardant, an epoxy resin in which the terminal epoxy group of the halogenated epoxy resin is sealed with a short-chain monoalcohol, and a flame retardant aid. A styrene-based flame retardant resin composition having excellent light resistance as well as properties and impact strength is disclosed.

JP 2006-199925 A

  Although the styrene flame retardant resin composition disclosed in Patent Document 1 is excellent in flame retardancy, impact strength, and light resistance, bromine compounds used as flame retardants have an impact on the environment and health. There are concerns and its use is in the direction of being restricted.

  The subject of this invention is reducing the addition amount of this brominated flame retardant in a styrene-based flame retardant resin composition using a brominated flame retardant, without impairing a flame retardance and impact strength. Moreover, this invention also makes it a subject to provide the molded object using the styrene-type flame retardant resin composition which concerns.

（ここで、ＲはＣ_nＨ_2n（ｎは１〜６の整数）の構造のアルキレン基、Ｘは臭素原子であり、ａおよびｂはそれぞれ独立に１〜４の整数でありａ＋ｂ≧２である。） As a result of intensive studies on the above problems, the inventor of the present invention has 8 parts by mass or more and 17 parts by weight of (B) brominated phthalimide compound represented by the following general formula (1) with respect to 100 parts by mass of (A) rubber-modified styrene resin. Styrenic flame retardant resin comprising less than part by mass, (C) 2 parts by mass or more and 7 parts by mass or less of flame retardant aid, and (D) 2 parts by mass or more and 10 parts by mass or less of talc. Composition.

(Where R is an alkylene group having a structure of C _n H _2n (n is an integer of 1 to 6), X is a bromine atom, a and b are each independently an integer of 1 to 4 and a + b ≧ 2.)

  Moreover, this invention provides the molded object which uses the said styrene-type flame retardant resin composition.

  According to the present invention, in a styrene-based flame retardant resin composition using a conventional brominated flame retardant, the amount of the flame retardant added can be reduced without impairing the flame retardancy and impact strength. The influence on can be reduced.

  (A) rubber-modified styrene resin used in the present invention is, for example, a rubber-like polymer dissolved in a mixed liquid of an aromatic vinyl monomer and an inert solvent, and stirred, bulk polymerization, suspension polymerization, solution polymerization. A polymer obtained by dispersing a rubbery polymer in the form of particles in an aromatic vinyl polymer matrix. Although there is no restriction | limiting in particular about the molecular weight of a matrix part, It is 0.50 or more in reduced viscosity ((eta) sp / C), Preferably it is 0.55-0.85. If the reduced viscosity exceeds 0.85, the flowability of the composition is too low to cause molding, and if it is less than 0.55, there is a problem that practically sufficient strength cannot be exhibited.

  Examples of the aromatic vinyl monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and combinations thereof. Most preferred.

  The volume average particle diameter of the rubber-like polymer contained in the rubber-modified styrenic resin is 0.5 to 3.0 μm. If the rubber particle diameter is too small, the impact resistance strength is drastically reduced. Conversely, if the particle diameter is too large, the appearance such as surface gloss of the molded product tends to be deteriorated.

  The rubbery polymer is not particularly defined, but is preferably a high cis polybutadiene rubber containing cis-1,4 bonds in a ratio of 90 mol% or more.

（ここで、ＲはＣ_nＨ_2n（ｎは１〜６の整数）の構造のアルキレン基、Ｘは臭素原子であり、ａおよびｂはそれぞれ独立に１〜４の整数でありａ＋ｂ≧２である。） The (B) brominated phthalimide compound used in the present invention is a flame retardant and has a structure represented by the following general formula (1).

(Where R is an alkylene group having a structure of C _n H _2n (n is an integer of 1 to 6), X is a bromine atom, a and b are each independently an integer of 1 to 4 and a + b ≧ 2.)

  Specifically, dibromo substitution products such as methylene-bis-phthalimide, ethylene-bis-phthalimide, propylene-bis-phthalimide, butylene-bis-phthalimide, pentylene-bis-phthalimide, hexylene-bis-phthalimide, tribromo substitution, Examples include tetrabromo-substituted, pentabromo-substituted, hexabromo-substituted, heptabromo-substituted, and octabromo-substituted. Preferred are octabromo-substituted products of ethylene-bis-phthalimide, propylene-bis-phthalimide, butylene-bis-phthalimide, pentylene-bis-phthalimide, and hexylene-bis-phthalimide. Particularly preferred is ethylene-bis-tetrabromophthalimide.

  (B) The brominated phthalimide compound is used by adding 8 parts by mass or more and less than 17 parts by mass to 100 parts by mass of (A) rubber-modified styrene resin. (B) If the brominated phthalimide compound is less than 8 parts by mass, sufficient flame retardancy cannot be obtained even if talc is added. Further, in the conventional styrene-based flame retardant resin composition, flame retardancy cannot be obtained unless bromine-based flame retardant is used in an amount of 17 parts by mass or more based on 100 parts by mass of the rubber-modified styrene resin. In (B), even if the addition amount of the brominated phthalimide compound is less than 17 parts by mass, the same flame retardancy as in the conventional case can be obtained.

  The flame retardant aid (C) used in the present invention functions to further enhance the flame retardant effect of the brominated phthalimide compound. For example, as antimony oxide, antimony trioxide, antimony tetroxide, antimony pentoxide, antimony Sodium borate, zinc borate, barium borate, anhydrous boric acid, anhydrous boric acid, etc., tin compounds, zinc stannate, zinc hydroxystannate, etc., molybdenum compounds, molybdenum oxide, ammonium molybdate, etc. Zirconium-based compounds include zirconium oxide, zirconium hydroxide and the like, and zinc-based compounds include zinc sulfide and the like, among which antimony trioxide is particularly preferable.

  The addition amount of the flame retardant aid is 2 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of the rubber-modified styrene resin. If the amount of the flame retardant aid is less than 2 parts by mass, it is difficult to obtain the effect, and if it exceeds 7 parts by mass, the flame retardancy of the resin composition is reduced, which is not preferable.

  In the present invention, (D) talc is added in addition to the rubber-modified styrenic resin, brominated phthalimide compound, and flame retardant aid. The amount of talc added is 2 to 10 parts by mass with respect to 100 parts by mass of the rubber-modified styrene resin. If the amount of talc added is less than 2 parts by mass, the flame retardancy will decrease, and if it exceeds 10 parts by mass, the impact strength will also decrease.

  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 flame-retardant resin composition can be obtained by further melt-kneading a mixture previously mixed with a mixing apparatus such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer. 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.

  Moreover, other additives can be used for the styrene-type flame retardant resin composition of this invention in the range which does not impair the objective of this invention. For example, antioxidant phenolic antioxidants, sulfur antioxidants, phosphorus antioxidants, lubricant fatty acid lubricants, aliphatic amide lubricants, metal soap lubricants, colorant pigments, dyes Non-ionic surfactant of antistatic agent, cationic surfactant, etc., styrene-butadiene block copolymer of reinforcing agent, styrene-butadiene-styrene block copolymer, mineral oil, polytetrafluoroethylene, etc. is there.

  The molded body of the present invention is a molded body molded using the above-described styrene-based flame retardant resin composition of the present invention, and is a OA device such as a word processor, personal computer, printer, copying machine, TV, VTR, It is preferably applied to home appliances such as audio. The molding method is not particularly limited, but is preferably injection molding, and a hot runner molding method using a large molding machine or a gas assist injection method is also preferably applied.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

[Rubber-modified styrene resin]
The rubber-modified styrene resin has a reduced viscosity of 0.70 dl / g, a rubbery polymer content of 9.4% by mass, a rubbery polymer gel content of 26.4% by mass, and a volume average particle size of 2.8 μm. A high cis polybutadiene rubber containing a certain cis 1,4 bond in a ratio of 90 mol% or more was used. The reduced viscosity, gel content, rubbery polymer content, and volume average particle size referred to herein were measured by the following methods.

<Reduced viscosity>
A mixed solvent of 15 ml of methyl ethyl ketone (MEK) and 15 ml of acetone is added to 1 g of rubber-modified styrenic resin, and dissolved by shaking at 25 ° C. for 2 hours. Then, the insoluble matter is settled by centrifugation, and the supernatant is taken out by decantation, and 500 ml. The methanol component is added to precipitate the resin component, and the insoluble component is filtered and dried. The resin component obtained by the same operation is dissolved in toluene to prepare a sample solution having a polymer concentration of 0.4% (weight / volume). The sample solution and pure toluene were kept constant at 30 ° C., and the solution flow seconds were measured with an Ubbelohde viscometer.

ηsp / C = (t1 / t0-1) / C
t0: Pure toluene flow down seconds t1: Sample solution flow down seconds C: Polymer concentration

<Gel content>
A rubber-modified styrene resin is added to toluene at a ratio of 2.5% by mass, dissolved by shaking at 25 ° C. for 2 hours, and then insoluble (gel content) by centrifugation (rotation speed 10,000 to 14000 rpm, separation time 30 minutes). And the supernatant liquid is removed by decantation to obtain a gel. Next, this swelling gel is preliminarily dried at 100 ° C. for 2 hours, and then dried in a vacuum dryer at 120 ° C. for 1 hour. It cooled to normal temperature with the desiccator, weighed precisely, and computed with the following formula.
Gel fraction (%) = ((ba) / S) × 100
a: Weight of centrifugal settling tube b: Weight of dried gel + centrifugal settling tube S: Weight of sample resin

<Rubber polymer content>
Dissolve the rubber-modified styrene resin in chloroform, add a certain amount of iodine monochloride / carbon tetrachloride solution and leave it in the dark for about 1 hour, add 15% by weight potassium iodide solution and 50 ml of pure water, Iodine monochloride was titrated with 0.1N sodium thiosulfate / ethanol aqueous solution and calculated from the amount of iodine monochloride added.

<Volume average particle diameter of rubbery polymer>
The rubber-modified styrene resin was completely dissolved in dimethylformamide and measured with a laser diffraction particle size distribution apparatus. As a measuring apparatus, a laser diffraction particle analyzer “LS-230 type” manufactured by Beckman Coulter, Inc. was used.

〔Flame retardants〕
As a brominated phthalimide compound, “SAYTEX-BT93” (ethylene-bis-tetrabromophthalimide) manufactured by Albemarle Japan Co., Ltd. is used. As a flame retardant for a comparative example, “TB60” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. A flame retardant was used.

[Flame retardant aid]
“PATOX-M” (antimony trioxide having a volume average particle diameter of 0.8 μm) manufactured by Nippon Seiko Co., Ltd. was used.

〔talc〕
“KP Talc” manufactured by Fuji Talc Kogyo Co., Ltd. (volume average particle size: 8 μm)
[Glass fiber]
“CS03NAFT164G” manufactured by Asahi Glass Co., Ltd. (average length: 13 μm)

[Production of Styrenic Flame Retardant Resin Composition]
After adding rubber-modified styrene-based resin, brominated phthalimide compound or epoxy-based flame retardant, flame retardant aid, talc or glass fiber at the blending ratio shown in Tables 1 and 2, and premixing with a mixer-type mixer, A fixed amount was supplied to a twin screw extruder and melt kneaded to obtain a styrene-based flame retardant resin composition. As polytetrafluoroethylene, PTFE31-JR manufactured by Mitsui DuPont Fluorochemical Co., Ltd. was used. As the styrene-butadiene-styrene block copolymer, Tufprene A manufactured by Asahi Kasei Chemicals Corporation was used.

The twin screw extruder is “TEM-26SS” (screw diameter Φ26 mm, 14 barrels) manufactured by Toshiba Machine Co., Ltd., and the operating conditions are as follows.
(1) Cylinder set temperature: 180 ° C. (conveying part) to 230 ° C. (kneading part to measuring part)
(2) Screw rotation speed: 300rpm
(3) Extrusion speed: 30 kg / h
(4) Resin temperature: 240-250 ° C

〔Evaluation method〕
Various measurements shown in Examples and Comparative Examples were performed by the following methods. The results are shown in Tables 1 and 2.

<Flame retardance>
The pellet of the styrene-based flame retardant resin composition is heated and dried at 70 ° C. for 3 hours, and then is 127 × 12.7 × 1.5 mm with an injection molding machine (“J100E-P” manufactured by Nippon Steel) A test piece for flammability evaluation was molded. Using such a test piece, a combustion test was performed based on the subject No. 94 vertical combustion test method (UL94) of US Underwriters Laboratories. V-0 or higher was considered acceptable.

<Charpy impact strength>
After drying the pellets of the styrene-based flame retardant resin composition at 70 ° C. for 3 hours, using an injection molding machine (“J100E-P” manufactured by Nippon Steel Works, Ltd.), an A-type test piece described in JIS K 7139 ( Dumbbell). Measurement was performed based on JIS K 7111-1 using a test specimen cut out from the center of the A-type test specimen and cut into a notch (type A, r = 0.25 mm). 10 kJ / m ² or more was regarded as acceptable.

  NG * in the table indicates NG due to glowing.

Claims (4)

(A) 8 parts by mass or more and less than 17 parts by mass of (B) brominated phthalimide compound represented by the following general formula (1) with respect to 100 parts by mass of the rubber-modified styrene-based resin; 2 to 7 parts by mass and (D) 2 to 10 parts by mass of talc.

(Where R is an alkylene group having a structure of C _n H _2n (n is an integer of 1 to 6), X is a bromine atom, a and b are each independently an integer of 1 to 4 and a + b ≧ 2.) The styrenic flame retardant resin composition according to claim 1, wherein the brominated phthalimide compound is ethylene-bis-tetrabromophthalimide. The styrene flame retardant resin composition according to claim 1 or 2, wherein the flame retardant aid is antimony trioxide.   A molded body comprising the styrene-based flame retardant resin composition according to any one of claims 1 to 3.