JP4616147B2 - Styrenic flame retardant thermoplastic resin composition - Google Patents

Description

The present invention relates to a styrene-based flame-retardant thermoplastic resin composition and a molded article comprising the same, and more specifically, a styrene-based resin that is excellent in high flame retardancy and excellent in releasability and scratch resistance at the time of release. The present invention relates to a flame retardant thermoplastic resin composition and a molded body comprising the same.

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

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 products, reduction of scratches that occur at the time of mold release is also regarded as important in order to increase the added value of the product.

In order to solve such a problem, in order to reduce scratches at the time of releasing a styrene-based resin, rubber particles within a specific particle size range are used in Japanese Patent Publication No. 03-68060 and Japanese Patent Application Laid-Open No. 07-62194. Known are a dispersed method, a method of containing a polyorganosiloxane having a specific viscosity in a styrene resin, and the like.
No. 03-68060 JP 07-62194 A

However, by selecting a styrenic resin in which rubber particles within a specific particle range are dispersed, improvements can be made except for molded products with specific shapes, but satisfactory products can be obtained for deep molded products. It is not done.

On the other hand, containing a polyorganosiloxane of a specific viscosity to a styrene resin, and providing slidability, a deep molded product can be almost satisfied, but the effect expected of low polyorganosiloxane content Can't hope. Moreover, when there is too much content, there existed a problem that the metal strip at the time of shaping | molding and the silver strip which is one of the appearance defect phenomena in a shaping | molding process were easy to generate | occur | produce.

In addition, styrene flame retardant thermoplastic resin compositions containing polyorganosiloxane (hereinafter abbreviated as silicone oil) suddenly cause poor resin biting in a specific injection molding machine during molding, resulting in short shots in the product. Have practical problems such as the occurrence of The sudden biting failure of the resin is that the styrene resin and polyorganosiloxane are incompatible, so the styrene flame retardant resin containing polyorganosiloxane is separated from the resin when it is plasticized and melted in the molding machine, This is considered to be caused by a decrease in the frictional resistance between the screw surface and the molten resin. Therefore, measures such as limiting the injection molding machine or mounting a screw having a special configuration are required, which leads to an increase in cost and is not preferable.

In view of such a current situation, the present invention provides a styrene-based flame-retardant thermoplastic resin composition that solves the above-described problems and has excellent flame resistance and excellent scratch resistance during release. is there.

In view of the present situation, the present inventors have conducted extensive studies, and as a result, have obtained a rubber-modified styrene resin having a specific rubber-like polymer, a brominated flame retardant, a flame retardant aid, and a basic inorganic compound. It has been found that a styrene-based flame retardant thermoplastic resin composition excellent in releasability and scratch resistance at the time of release can be obtained by combining the above and the like.

「式中のＸは臭素原子を表し、ｊ及びｋは０〜５の整数で、ｊ＋ｋ≧２、ＲはＣ_nＨ_2n（ｎは１〜１０の整数）の構造を表す」 That is, the present invention provides 0.1 to 5 parts by weight of bromine-based flame retardant (B) 8 to 15 parts by weight and flame retardant aid (C) to 100 parts by weight of rubber-modified styrene resin (A). A styrene-based flame retardant thermoplastic resin composition containing parts by mass,
The rubber-modified styrenic resin (A), all of the rubbery polymer, the cis-1,4 bond to a high-cis polybutadiene rubber containing a ratio of more than 90 mol%, the volume average particle of the rubber-like polymer The diameter is 0.5 to 3.0 μm,
The content of the high cis polybutadiene rubber in the styrene-based flame retardant thermoplastic resin composition is 4.5% by mass or more and 7.0% by mass or less,
The present invention relates to a styrene-based flame retardant thermoplastic resin composition, wherein the brominated flame retardant (B) is a halogenated diphenylalkane represented by the following general formula (I).

“X in the formula represents a bromine atom, j and k are integers of 0 to 5, j + k ≧ 2, R represents a structure of C _n H _2n (n is an integer of 1 to 10)”

According to the technique of the present invention, it is possible to obtain a styrene-based flame-retardant thermoplastic resin composition that is excellent in mold release and scratch resistance at the time of mold release and that retains high flame retardancy. The styrene-based flame retardant thermoplastic resin composition obtained in this way is useful in the field of high functionality for deep molding products such as recent office automation equipment and home appliances, and has a great industrial utility value. . Specifically, it is expected to be used for container-shaped deep interior / exterior housing materials such as office equipment and information equipment.

The rubber-modified styrenic resin (A) is, for example, dissolving a rubber-like polymer in a mixture of an aromatic vinyl monomer and an inert solvent and stirring to perform bulk polymerization, suspension polymerization, solution polymerization, or the like. Is a polymer obtained by dispersing a rubbery polymer in the form of particles in a matrix of an aromatic vinyl polymer. Although there is no restriction | limiting in particular about the molecular weight of a matrix part, 0.50 or more is preferable at reduced viscosity ((eta) sp / C), Preferably it is 0.55-0.85.

If it exceeds 0.85, the fluidity of the composition is too low to cause molding, and if it is less than 0.55, practically sufficient strength cannot be exhibited .

Although there is no restriction | limiting in particular about the volume average particle diameter of a rubber-like polymer, Generally it is 0.4-6.0 micrometers, Preferably 0.5-3.0 micrometers is suitable. If the rubber particle size is too small, the impact resistance strength is drastically reduced. Conversely, if the particle size is too large, the appearance of the molded product, such as surface gloss, tends to deteriorate.

The aromatic vinyl monomer is mainly styrene. Mention may be made of Ο-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene and the like, and combinations thereof. Styrene is most preferred.

Examples of the rubber-like polymer include polybutadiene, polyisoprene, and styrene-butadiene copolymer. Examples of the polybutadiene include high cis polybutadiene having a high cis bond content and low cis polybutadiene having a low cis bond content. Can be mentioned. Among them, a high cis polybutadiene rubber in which 70% by mass or more of the rubber-like copolymer contains cis-1,4 bonds in a ratio of 90 mol% or more is preferable.

The content of the high cis polybutadiene rubber in the styrene-based flame retardant thermoplastic resin composition is preferably 4.5% by mass or more.

「式中のＸは臭素原子及び／または塩素原子を表し、ｊ及びｋは０〜５の整数で、ｊ＋ｋ≧２、ＲはＣ_ｎＨ_２ｎ（ｎは１〜１０の整数）の構造を表す」 The brominated flame retardant (B) used in the composition of the present invention is a diphenylalkane such as diphenylmethane, 1,2-diphenylethane, 1-methyl-1,2-diphenylethane, 1,4-diphenyl. Examples include butane, 1,6-diphenylhexane and the like obtained by nuclear substitution with one or more halogen atoms, preferably 4 to 5 bromine atoms attached to one phenyl group. Among them, the following general formula (I) The decabromodiphenylethane represented by these is preferable.

“X in the formula represents a bromine atom and / or a chlorine atom, j and k are integers of 0 to 5, j + k ≧ 2, and R represents a structure of C _n H _2n (n is an integer of 1 to 10). "

The addition amount of the brominated flame retardant (B) is 4 to 20 parts by mass, preferably 5 to 15 parts by mass with respect to 100 parts by mass of the rubber-modified styrene resin (A).

The flame retardant aid (C) used in the composition of the present invention functions to further enhance the flame retardant effect of the brominated flame retardant (B). For example, antimony trioxide, four Antimony oxide, antimony pentoxide, sodium antimonate, etc., boron-based compounds such as zinc borate, barium metaborate, anhydrous zinc borate, anhydrous boric acid, etc., tin-based compounds such as zinc stannate, zinc hydroxystannate, etc., molybdenum-based Examples of the compound include molybdenum oxide and ammonium molybdate, examples of the zirconium-based compound include zirconium oxide and zirconium hydroxide, and examples of the zinc-based compound include zinc sulfide. Among these, antimony trioxide is particularly preferable.

The addition amount of the flame retardant aid (C) is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber-modified styrene resin (A). This is not preferable because it increases the glowing behavior.

A known mixing technique can be applied to the method for mixing the styrene-based flame retardant thermoplastic 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.

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

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

The rubber-modified styrene resins (A1), (A2), and (A3) used in Examples and Comparative Examples had the following compositions, respectively. The composition of (A1) is a low-cis polybutadiene rubber having a reduced viscosity of 0.55 dl / g, a rubbery polymer content of 9.3% by mass, a gel content of 28.1% by mass, and a volume average particle size of 2.5 μm. used. The composition of (A2) has a reduced viscosity of 0.60 dl / g, a rubbery polymer content of 13.6% by mass, a rubbery polymer gel content of 27.6% by mass, and a volume average particle size of 0.77 μm. A low-cis polybutadiene rubber was used. The composition of (A3) has a reduced viscosity of 0.73 dl / g, a rubbery polymer content of 9.0% by mass, a rubbery polymer gel content of 22.8% by mass, and a volume average particle size of 2.53 μm. A high cis polybutadiene rubber containing cis 1,4 bonds in a proportion 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.

Measurement of reduced viscosity (ηsp / C): A mixed solvent of 15 ml of methyl ethyl ketone (MEK) and 15 ml of acetone is added to 1 g of a rubber-modified styrene resin, dissolved by shaking at 25 ° C. for 2 hours, and then the insoluble matter is precipitated by centrifugation. The supernatant liquid is taken out by decantation, 500 ml of methanol 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

Measurement of gel content: Rubber-modified styrene resin was added to toluene at a ratio of 2.5%, dissolved by shaking at 25 ° C. for 2 hours, and then insoluble by centrifugation (rotation speed: 10,000 to 14000 rpm, separation time 30 minutes). The fraction (gel fraction) is allowed to settle, and the supernatant 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: Centrifugal settling tube weight
b: Weight of dried gel + centrifuge tube
S: Sample resin weight

Measurement of rubbery polymer content: A rubber-modified styrene resin is dissolved in chloroform, a certain amount of iodine monochloride / carbon tetrachloride solution is added, and the mixture is allowed to stand in a dark place for about 1 hour, and then a 15% by mass potassium iodide solution. And 50 ml of pure water were added, excess iodine monochloride was titrated with 0.1N sodium thiosulfate / ethanol aqueous solution, and the amount of iodine monochloride added was calculated.

Measurement of volume average particle diameter of rubbery polymer: The rubber-modified styrene resin composition was completely dissolved in dimethylformamide and measured with a laser diffraction particle size distribution apparatus.
Measuring device: Coulter laser diffraction particle analyzer LS-230

The brominated flame retardant (B1) used SAYTEX-8010 (hereinafter, abbreviated as S8010) manufactured by Albemarle, and (B2) used SR245 manufactured by Daiichi FR.

As the flame retardant aid (C), antimony trioxide (PATOX-M, manufactured by Nippon Seiko Co., Ltd.) having a volume average particle size of 0.8 μm manufactured by Nippon Seiko Co., Ltd. was used.

In addition, as a common additive, a basic inorganic compound, sodium aluminosilicate mixture, ethylene bis stearic acid amide, mineral oil, and inorganic colorant were used.

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

The flame retardancy was measured according to a vertical combustion test method of Subject No. 94 of US Underwriters Laboratories, Inc., and the flammability of a test piece thickness of 1/12 inch was evaluated. The evaluation results are shown as follows.
Pass: V-2 level or higher.
Fail: V-2 level or less.

The melt flow rate (MFR) was measured according to JIS K7210 at 200 ° C. and a load of 49 N.

Measurement of releasability is performed by using a mold release resistance mold (molded product dimensions, length / width / depth: 125 × 54 × 42 mm) with an ejector pin mounted on an injection pin 100t (JSW100EP) manufactured by Nippon Steel Co., Ltd. The set-up conditions of each sample were searched, continuous molding was performed under the same conditions, and the ejector force of the ejector pin when the molded product was released during mold opening was measured. The releasability is evaluated by the maximum releasable resistance value (V). The smaller the numerical value, the better the releasability.

The molding conditions were a cylinder temperature of 220 ° C., a mold temperature of 30 ° C., and a holding pressure of 1.9 MPa.

The moldability was evaluated by searching for the setup conditions of each sample with an injection molding machine 100t (JSW100EP) manufactured by Nippon Steel Co., Ltd., performing continuous molding under the same conditions, and observing the occurrence of short shots. The evaluation results are shown as follows.
○: No problem.
Δ: Short shot defect suddenly occurred during continuous molding.
X: Poor bite.

Scratch evaluation was performed by attaching a mold for molding technician test (molded product dimensions, length / width / depth: 100 × 75 × 45 mm) to an injection molding machine 100t (JSW100EP) manufactured by Nippon Steel Co., Ltd. Searching for setup conditions, continuous molding was performed under the same conditions, and scratches generated at the corners of the molded product when the mold was opened were visually observed. The evaluation results are shown as follows.
○: Not generated.
Δ: Not noticeable.
X: It stands out.
Production of flame retardant thermoplastic resin composition

After pre-mixing the rubber-modified styrene resin (A1, A2, A3 alone / in combination) and the flame retardant aid (C) in a mixing ratio shown in Table 1 with a mixer-type mixer. After the quantitative supply to the twin screw extruder and melt-kneading, the brominated flame retardants (B1, B2) are further quantitatively supplied from the middle of the extruder at the blending ratio shown in Table 2 to obtain a flame retardant resin composition. It was.

During the premixing, a mixture of sodium aluminosilicate and A-type zeolite, ethylenebisstearic acid amide, zinc stearate, mineral oil, silicone oil, and inorganic colorant were also added at the same time.

The operating conditions of the twin screw extruder (H-KTX30XHT manufactured by Kobe Steel, Ltd., screw diameter Φ30 mm, L / D = 46.8) 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: 50kg / h
(4) Resin temperature: 240-250 ° C

Example 1
Use S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A3). The content of rubbery polymer in the final product is 4.5% by mass. Furthermore, the high-cis polybutadiene rubber content in the rubbery polymer was adjusted to 100% by mass. The results are shown in Table 1.

Example 2
Use S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A3). Rubber-like polymer content in the final product is 6.0% by mass. Furthermore, the high-cis polybutadiene rubber content in the rubbery polymer was adjusted to 100% by mass. The results are shown in Table 1.

Example 3
Use S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A3). The rubbery polymer content in the final product is 7.0% by mass. Furthermore, the high-cis polybutadiene rubber content in the rubbery polymer was adjusted to 100% by mass. The results are shown in Table 1.

Comparative Example 1
Use S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A1). The rubbery polymer content in the final product is 7.0% by mass. Furthermore, the high-cis polybutadiene rubber content ratio in the rubber-like polymer was adjusted to zero mass%. The results are shown in Table 1.

Comparative Example 2
Combination use of brominated flame retardant (B1) S8010, flame retardant aid (C), rubber-modified styrene resin (A1) and (A2). The rubbery polymer content in the final product is 8.0% by mass. Furthermore, the high-cis polybutadiene rubber content ratio in the rubber-like polymer was adjusted to zero mass%. The results are shown in Table 1.

Comparative Example 3
Using brominated flame retardant (B2) SR245, flame retardant aid (C), rubber-modified styrene resin (A3). Adjustment was made so that the rubbery polymer content in the final product was 4.0% by mass and the high-cis polybutadiene rubber content in the rubbery polymer was 100% by mass. Furthermore, 0.3 part of silicone oil (D: viscosity 100 cst / 25 ° C., SH200 oil manufactured by Toray Dow Corning Silicone Co., Ltd.) was added to 100 parts by weight of the rubber-modified styrene resin (A3). The results are shown in Table 1.

Comparative Example 4
Combined use of S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A2) and (A3). The rubbery polymer content in the final product is 4.0% by mass. Furthermore, the high-cis polybutadiene rubber content ratio in the rubber-like polymer was adjusted to 62.5% by mass. The results are shown in Table 1.

Comparative Example 5
Use brominated flame retardant (B1) S8010, flame retardant aid (C), rubber-modified styrene resin (A2). The rubbery polymer content in the final product is 7.0% by mass. Furthermore, the high-cis polybutadiene rubber content ratio in the rubber-like polymer was adjusted to zero mass%. The results are shown in Table 1.

Comparative Example 6
Use brominated flame retardant (B1) S8010, flame retardant aid (C), rubber-modified styrene resin (A3). The rubbery polymer content in the final product is 7.0% by mass. Furthermore, the high-cis polybutadiene rubber content in the rubbery polymer was adjusted to 100% by mass. The results are shown in Table 1.

Comparative Example 7
Use S8010 of brominated flame retardant (B1), flame retardant aid (C), rubber-modified styrene resin (A1). The rubbery polymer content in the final product is adjusted to 4.0% by mass, and the high-cis polybutadiene rubber content in the rubbery polymer is adjusted to be 0% by mass. Furthermore, 0.3 part of silicone oil (D: viscosity 100 cst / 25 ° C., SH200 oil manufactured by Toray Dow Corning Silicone Co., Ltd.) was added to 100 parts by weight of the rubber-modified styrene resin (A1). The results are shown in Table 1.

Comparative Example 8
Combination use of brominated flame retardant (B1) S8010, flame retardant aid (C), rubber-modified styrene resin (A1) and (A2). The rubbery polymer content in the final product was adjusted to 6.0% by mass, and the high-cis polybutadiene rubber content in the rubbery polymer was adjusted to 0% by mass. Furthermore, silicon oil (D: viscosity: 100 cst / 25 ° C., SH200 oil manufactured by Toray Dow Corning Silicone Co., Ltd.) is 0.5 Part was added. The results are shown in Table 1.

In Comparative Examples 1, 2, 5, and 6 that are not added with silicone oil, no shoot shot is observed even when a specific injection molding machine is used, but a rubber-modified styrene resin containing a high-cis polybutadiene rubber. Except for Comparative Example 6 using No. 1, scratches at the time of release are conspicuous. Furthermore, Comparative Examples 1 and 2 do not achieve the target of flame retardancy. Further, in Comparative Example 6 in which 10 parts of the flame retardant aid was added, the target flame retardance performance was not achieved due to the occurrence of glowing. However, even in the rubber-modified styrene resin containing high-cis polybutadiene rubber, Comparative Example 4 used in combination with low-cis polybutadiene rubber having a volume average rubber particle diameter of 0.77 μm (low-sis / high-cis: 1/3) is a scratch at the time of release. Stands out.

In Comparative Examples 3, 7, and 8 that are silicone oil addition systems, improvement in scratch resistance at the time of mold release is recognized, but there is a concern that molding defects may occur due to short shots in a specific injection molding machine during molding. .

On the other hand, Examples 1-3 have high flame retardancy, and even if a specific injection molding machine is used, the occurrence of short shots is not recognized. Furthermore, scratches at the time of release are also improved.

The styrenic flame-retardant thermoplastic resin composition of the present invention and a molded article comprising the same are useful in the field of high functionality for home appliances, OA equipment and the like.

Claims (3)

Styrenic containing 0.1 to 5 parts by mass of brominated flame retardant (B) 8 to 15 parts by mass and flame retardant auxiliary (C) to 100 parts by mass of rubber-modified styrene resin (A) A flame retardant thermoplastic resin composition comprising:
The rubber-modified styrenic resin (A), all of the rubbery polymer, the cis-1,4 bond to a high-cis polybutadiene rubber containing a ratio of more than 90 mol%, the volume average particle of the rubber-like polymer The diameter is 0.5 to 3.0 μm,
The content of the high cis polybutadiene rubber in the styrene-based flame retardant thermoplastic resin composition is 4.5% by mass or more and 7.0% by mass or less,
A styrene-based flame retardant thermoplastic resin composition, wherein the brominated flame retardant (B) is a halogenated diphenylalkane represented by the following general formula (I).

“X in the formula represents a bromine atom, j and k are integers of 0 to 5, j + k ≧ 2, R represents a structure of C _n H _2n (n is an integer of 1 to 10)”   The styrenic flame retardant thermoplastic resin composition according to claim 1, wherein the flame retardant aid (C) is antimony trioxide.   The molded object which consists of a styrene-type flame retardant thermoplastic resin composition of Claim 1 or 2.