JP6360700B2 - 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 field 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. Furthermore, in the molding of deep molded articles and the like, it is also important to reduce the scratches generated at the time of release in order to increase the added value of the product.

  Patent Document 1 discloses that a rubber-modified styrenic resin having a specific rubber-like polymer is combined with a bromine-based flame retardant and a flame retardant aid, so that it has high flame resistance and impact strength, as well as scratch resistance at the time of release. A styrene-based flame retardant resin composition having excellent properties is disclosed.

JP 2007-39626 A

  Although the styrene flame retardant resin composition disclosed in Patent Document 1 is excellent in flame retardancy, impact strength, and scratch 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.

The styrene flame retardant resin composition of the present invention is (B) brominated diphenylalkane of 4.0 parts by mass or more and 8.0 parts by mass represented by the following general formula with respect to 100 parts by mass of (A) rubber-modified styrene resin. Less than part by mass, (C) 0.1 to 3.0 parts by mass of flame retardant aid, and (D) 0.1 to 5.0 parts by mass of talc,
(A) the rubber-modified styrenic resin is more than 70 wt% of the rubbery polymer containing the, Ri high-cis polybutadiene rubber der containing cis-1,4 bonds at a ratio of more than 90 mol%,
(B) the brominated diphenylalkane is decabromodiphenylethane, wherein (C) the flame retardant agent, characterized trioxide antimony der Rukoto.

[Wherein, R represents an alkylene group of C _n H _2n (n is an integer of 1 to 10), X represents a bromine atom, j and k are each independently an integer of 1 to 5, and j + k ≧ 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 brominated flame retardant, it is possible to reduce the amount of flame retardant added without impairing the flame retardancy and impact strength, and to the environment and health. The influence can be reduced.

  By adding a small amount of talc to a conventional styrene-based flame retardant resin composition, the present inventors can reduce the amount of brominated flame retardant added to the extent that conventional flame retardant properties are reduced. The inventors found that the flame retardancy does not decrease and achieved the present invention. That is, the styrene-based flame retardant resin composition of the present invention has (B) brominated diphenylalkane of 4.0 parts by mass or more and less than 8.0 parts by mass as a flame retardant with respect to (A) 100 parts by mass of the rubber-modified styrene resin. And (C) 0.1 to 3.0 parts by mass of a flame retardant aid and (D) 0.1 to 5.0 parts by mass of talc. Each component will be described below.

The rubber-modified styrenic resin used in the present invention is, for example, by dissolving a rubber-like polymer in a mixed liquid of an aromatic vinyl monomer and an inert solvent and stirring to perform bulk polymerization, suspension polymerization, solution polymerization, etc. This refers to 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 dl / g or more by reduced viscosity ((eta) _sp / C), Preferably it is 0.55-0.85 dl / g. If the reduced viscosity exceeds 0.85 dl / g, the fluidity of the composition is too low to cause molding, and if it is less than 0.55 dl / g, practically sufficient strength cannot be exhibited. is there. Although there is no restriction | limiting in particular about rubber content, 4-15 mass% generally used for rubber-modified styrene-type resin 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 combinations thereof. Most preferred.

  Although there is no restriction | limiting in particular about the volume average particle diameter of the rubber-like polymer contained in rubber-modified styrene resin, Generally it is 0.4-6.0 micrometers, Preferably it is 0.5-3.0 micrometers. . 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.

  Examples of the rubbery polymer contained in the rubber-modified styrene resin include polybutadiene, polyisoprene, and styrene-butadiene copolymer. The polybutadiene has a high cis bond content and high cis polybutadiene and cis bond. Examples include low-cis polybutadiene having a low content.

  In the present invention, 70% by mass or more of the rubber-like polymer is a high cis polybutadiene rubber containing cis-1,4 bonds in a ratio of 90 mol% or more, and the styrene-based flame retardant resin composition of the present invention. It is preferably contained in the product at a ratio of 4.5% by mass or more.

  The brominated diphenylalkane used in the present invention is a flame retardant and has a structure represented by the following general formula.

In the formula, R represents an alkylene group of C _n H _2n (n is an integer of 1 to 10), X represents a bromine atom, j and k are each independently an integer of 1 to 5, and j + k ≧ 2.

  Specifically, dibromo substitution such as diphenylmethane, 1,2-diphenylethane, 1,3-diphenylpropane, 1,6-diphenylhexane, tribromo substitution, tetrabromo substitution, pentabromo substitution, hexabromo substitution, heptabromo Substituted, octabromo-substituted, nonabromo-substituted, decabromo-substituted. Preferred are octabromo-substituted, nonabromo-substituted and decabromo-substituted diphenylalkanes, and particularly preferred is decabromodiphenylethane.

  Brominated diphenylalkane is used by adding 4.0 parts by weight or more and less than 8.0 parts by weight to 100 parts by weight of the rubber-modified styrene resin. When the brominated diphenylalkane is less than 4.0 parts by mass, sufficient flame retardancy cannot be obtained even if talc is added. Moreover, in the conventional styrene-based flame retardant resin composition, flame retardance was not obtained unless a brominated flame retardant was used in an amount of 8.0 parts by mass or more with respect to 100 parts by mass of the rubber-modified styrene resin. In the present invention, the flame retardancy similar to the conventional one can be obtained when the addition amount of brominated diphenylalkane is less than 8.0 parts by mass.

  The flame retardant aid used in the present invention functions to further enhance the flame retardant effect of brominated diphenylalkane, such as antimony trioxide, antimony tetraoxide, antimony pentoxide, sodium antimonate, etc. Zinc borate, barium metaborate, anhydrous borate, anhydrous boric acid, etc. as boron compounds, zinc stannate, zinc hydroxystannate, etc. as tin compounds, molybdenum oxide, ammonium molybdate, etc., zirconium series as molybdenum compounds Examples of the compound include zirconium oxide and zirconium hydroxide, and examples of the zinc-based compound include zinc sulfide. Among them, antimony trioxide is particularly preferable.

  The addition amount of the flame retardant aid is 0.1 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the rubber-modified styrene resin. If the flame retardant aid is less than 0.1 parts by mass, it is difficult to obtain the effect, and if it exceeds 3.0 parts by mass, the flame retardancy of the resin composition is reduced, which is not preferable.

  In the present invention, talc is added in addition to the rubber-modified styrenic resin, brominated diphenylalkane and flame retardant aid. The amount of talc added is 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber-modified styrene resin. Even if the amount of talc added is less than 0.1 parts by mass or more than 5.0 parts by mass, the flame retardancy is lowered, and particularly when it exceeds 5.0 parts by mass, the impact strength is also lowered.

  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.

  In addition, the styrene-based flame retardant resin composition of the present invention contains other additives such as plasticizers, lubricants, stabilizers, ultraviolet absorbers, fillers, reinforcing agents and the like within a range not to impair the purpose of the present invention. Can be added.

  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 styrenic resin used had a reduced viscosity of 0.70 dl / g, a gel content of 26.4% by mass, a rubbery polymer of 9.4% by mass, and the volume average particle diameter of the rubbery polymer. 2.8 μm, all of which are high-cis polybutadiene rubbers containing cis-1,4 bonds in a proportion of 90 mol% or more. 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.

η _sp / 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, then 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 the brominated diphenylalkane, “SAYTEX-8010” (decabromodiphenylethane) manufactured by Albemarle Japan Co., Ltd. is used, and “TB60” (epoxy flame retardant) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. is used as the flame retardant for the comparative example. Using.

[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 styrenic resin, flame retardant aid, talc or glass fiber at the blending ratio shown in Table 1, premixed with a mixer-type mixer, and then quantitatively supplied to a twin screw extruder and after melt kneading Further, brominated diphenylalkane or epoxy flame retardant was supplied from the middle of the extruder at a blending ratio shown in Table 1 to obtain a styrene flame retardant resin composition.

The twin screw extruder is “H-KTX30XHT” (screw diameter φ30 mm, L / D = 46.8) manufactured by Kobe Steel, Ltd., and the operating conditions are as follows.
(1) Cylinder set temperature: 180 ° C. (conveying part) to 200 ° C. (kneading to measuring part)
(2) Screw rotation speed: 450rpm
(3) Extrusion speed: 50 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 Table 1.

<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 × 0.8 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.

<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).

NG ^* in the table indicates NG due to glowing.

Claims (2)

(A) 4.0 parts by mass or more and less than 8.0 parts by mass of (B) brominated diphenylalkane represented by the following general formula with respect to 100 parts by mass of the rubber-modified styrenic resin; 1 part by weight or more and 3.0 parts by weight or less, and (D) talc 0.1 parts by weight or more and 5.0 parts by weight or less,
(A) the rubber-modified styrenic resin is more than 70 wt% of the rubbery polymer containing the, Ri high-cis polybutadiene rubber der containing cis-1,4 bonds at a ratio of more than 90 mol%,
(B) the brominated diphenylalkane is decabromodiphenylethane, wherein (C) a styrene-based flame retardant resin composition flame retardant aid is characterized trioxide antimony der Rukoto.

[Wherein, R represents an alkylene group of C _n H _2n (n is an integer of 1 to 10), X represents a bromine atom, j and k are each independently an integer of 1 to 5, and j + k ≧ 2] A molded body comprising the styrene-based flame retardant resin composition according to claim 1 .