JP2014012776A - Styrenic flame-retardant resin composition excellent in hinge properties and formed article consisting of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a styrenic flame-retardant resin composition having high flame retardancy and excellent hinge properties; and a formed article consisting the same.SOLUTION: Provided are: a styrenic flame-retardant resin composition excellent in hinge properties which is characterized by containing, relative to (A) 100 pts.mass of a rubber-modified polystyrene resin, (B) 7-15 pts.mass of a bromine flame retardant having a melting point of over 300°C, (C) 1-6 pts.mass of a flame retardant aid and (D) 0.1-1.5 pts.mass of a higher fatty acid metal salt; and a formed article consisting of the same.

Description

The present invention provides a styrene-based flame retardant resin composition having a high degree of flame retardancy and excellent hinge characteristics, and a molded article comprising the same.

Styrenic resins are used in a wide range of applications by taking advantage of their properties. Among them, styrene-based flame retardant resins imparted with a high degree of flame retardancy are used in various fields such as OA equipment such as personal computers, printers, copying machines, and home appliances such as TVs and audios. In recent years, these molded products such as OA equipment and home appliances have been required to be integrally molded from the viewpoint of simplifying assembly work. In response to this requirement, integral molding is performed by introducing a hinge part into the molded product. It is possible. However, styrene-based flame retardant resins containing flame retardants are known to have inferior physical properties compared to styrene resins not containing flame retardants. Therefore, it is strongly desired to improve the hinge characteristics while maintaining the performance.

On the other hand, in a styrene-based resin that does not contain a flame retardant, a hinge characteristic is improved by using a method of improving hinge characteristics by blending an organopolysiloxane with a polystyrene resin (see Patent Document 1) and a styrene-butadiene block copolymer. Although the technique (refer patent document 2) which improves this is known, there is no report about the styrene-type flame retardant resin which has high flame retardance and a hinge characteristic.

JP 60-144530 A JP 2004-18800 A

In view of such a current situation, the present invention provides a styrene-based flame-retardant resin composition having high flame retardancy and excellent hinge characteristics, and a molded body comprising the same, by solving the above problems. is there.

As a result of diligent research to solve these various problems, the present inventor has achieved high flame retardancy by blending a rubber-modified polystyrene resin with a brominated flame retardant, further a flame retardant aid and a higher fatty acid metal salt. A styrene-based flame retardant resin composition having hinge characteristics while retaining the above has been found and the present invention has been achieved.

That is, the present invention is as follows.

(1). (A) For 100 parts by mass of rubber-modified polystyrene resin, (B) 7 to 15 parts by mass of brominated flame retardant having a melting point exceeding 300 ° C., (C) 1 to 6 parts by mass of flame retardant aid, and (D) A styrene-based flame retardant resin composition having excellent hinge characteristics, comprising 0.1 to 1.5 parts by mass of a higher fatty acid metal salt.
(2). The styrene-based flame retardant resin composition having excellent hinge characteristics as described in (1) above, wherein the rubber content in the styrene-based flame retardant resin composition is 8.0% by mass or more.
(3). (B) The styrene-based flame retardant resin composition having excellent hinge characteristics according to (1) or (2), wherein the brominated flame retardant is 1,2-bis (pentabromophenyl) ethane.
(4). (C) The styrene-based flame retardant resin composition having excellent hinge characteristics according to any one of (1) to (3), wherein the flame retardant aid is antimony trioxide.
(5). (D) The styrene flame-retardant resin composition having excellent hinge characteristics according to any one of (1) to (4), wherein the higher fatty acid metal salt is zinc stearate.
(6). A molded article obtained by molding the styrene-based flame retardant resin composition having excellent hinge characteristics according to any one of (1) to (5).

Since the styrene-based flame retardant resin composition of the present invention is excellent in flame retardancy and hinge characteristics, it is advantageous to use it in OA equipment and home appliance parts having a hinge.

It is a side view of the hinge-shaped test piece used for this invention. It is a top view of the hinge-shaped test piece used for this invention. It is a hinge part enlarged view of the hinge shape test piece used for this invention.

Below, the styrene-type flame retardant resin composition of this invention is demonstrated in detail. The hinge referred to in the present invention has, for example, a shape as shown in the figure, and refers to a thin portion to which one or more bending or bending loads are applied in a certain part of a molded product, and is called a hinge. There is no restriction | limiting in particular about the shape of a hinge, A sheet | seat shape, a strip | belt shape, a string shape etc. are included. Further, the hinge is not defined with respect to its thickness and length. The hinge characteristic in the present invention is defined as durability against bending or bending load in the hinge.

As the flame retardant resin composition for hinge parts, the rubber content in the styrene flame retardant resin composition is preferably 8.0% by mass or more. The rubber content is preferably determined in consideration of the balance between impact strength and rigidity necessary for the molded product.

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.

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.

In addition, the brominated flame retardant having a melting point (B) exceeding 300 ° C. used in the present invention is generally used in this field. For example, decabromodiphenyl ether (melting point: 305 ° C.), ethylenebistetrabromophthalimide (Melting point: 456 ° C.) 1,2-bis (pentabromophenyl) ethane (melting point: 350 ° C.) and the like. Of these, 1,2-bis (pentabromophenyl) ethane is preferably used.

(C) The flame retardant aid functions to further enhance the flame retardant effect of the flame retardant (B). For example, antimony oxide such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, boron, etc. Zinc borate, barium metaborate, anhydrous zinc borate, anhydrous boric acid, etc. as tin compounds, stannic oxide, zinc stannate, zinc hydroxystannate, etc. as tin compounds, molybdenum oxide, ammonium molybdate as molybdenum compounds Zirconium-based compounds include zirconium oxide and zirconium hydroxide, and zinc-based compounds include zinc sulfide and the like. Among them, it is particularly preferable to use antimony trioxide.

(C) 1-6 mass parts with respect to 100 mass parts of rubber-modified polystyrene resin, Preferably 1-3 mass parts is suitable for the addition amount of a flame-retardant adjuvant. When the amount of the (C) flame retardant auxiliary added is less than 1 part by mass relative to the (A) rubber-modified styrene resin, the flame retardancy is poor. Exceeding 6 parts by mass is not preferable because it increases the glowing behavior during combustion.

The (D) higher fatty acid metal salt used in the present invention is generally used in this field, and examples thereof include stearic acid metal salts, lauric acid metal salts, and ricinoleic acid metal salts. Among these, metal (Ca, Zn, Mg, Ba, etc.) salts of stearic acid are preferably used.

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.

There is no particular limitation on the molding method for obtaining a molded product from the styrene-based flame retardant resin composition of the present invention, but injection molding is preferable, and injection molding such as a toner cartridge container is particularly preferable.

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 styrenic resin (A) used in Examples and Comparative Examples has the following composition. A reduced viscosity of the matrix part of 0.77 dl / g, a rubbery polymer content of 9.2% by mass, a rubbery polymer gel content of 27.1% by mass, and a volume average particle size of 2.76 μm cis 1, A high-cis polybutadiene rubber containing 4 bonds in a proportion of 90 mol% or more was used. The rubber-modified polystyrene resin used was abbreviated as HI-PS.

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

Measurement of gel content: 2.5% (mass / volume) of rubber-modified styrene resin was added to toluene at a rate of 2.5% (mass / volume) and dissolved by shaking at 25 ° C. for 2 hours, followed by centrifugation (rotation speed: 10,000 to 14000 rpm, separation time 30 minutes), the insoluble matter (gel content) was allowed to settle, and the supernatant was removed by decantation to obtain a gel. Next, this swollen gel was 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: Mass of centrifugal settling tube
b: Dry gel + centrifuge tube mass
S: Sample resin mass

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 rubber-like polymer: A rubber-modified styrene resin was completely dissolved in dimethylformamide and measured with a laser diffraction particle size distribution apparatus.
Measuring device: Coulter laser diffraction particle analyzer LS-230

(B) Brominated flame retardants include trade name SAYTEX 8010 manufactured by Albemarle, which is 1,2-bis (pentabromophenyl) ethane, and trade name SAYTEX BT-93 manufactured by Albemarle, which is ethylenebistetrabromophthalimide. 2,4,6-tris (2,4,6-tribromophenoxy) -1,3,5-triazine, trade name Piroguard SR245 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. was used.

(C) As a flame retardant aid, trade name AT-3CN which is antimony trioxide manufactured by Suzuhiro Chemical Co., Ltd. was used.

(D) Zinc stearate GP, a trade name of zinc stearate made by NOF, was used as the higher fatty acid salt.

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) Flame retardant aid (D) Higher fatty acid metal salt in the blending amounts shown in Tables 1 and 2, all these components were combined with a Henschel mixer ( The mixture was premixed by Mitsui Miike Chemical Industries, Ltd. (FM20B), supplied to a twin-screw extruder (Toshiki Machine Co., Ltd., TEM26SS) to form a strand, water-cooled, and then 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 test piece for the hinge characteristic test was molded at a cylinder temperature of 220 ° C. with an injection molding machine (manufactured by Nippon Steel Works, J100E-P).

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

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.

Hinge characteristics are measured by leaving a hinge-shaped test piece (thickness 2 mm, length 100 mm, width 48 mm) as shown in the figure at 23 ° C. and 20 RH for 24 hours, then bending the hinge portion at an angle of 235 °, and then returning to the original position. The operation to return to 0 ° was performed at a rate of once per second, and the number of times until the test piece was broken and broken was measured. Measurement was performed at n = 10, and the average of the number of times was defined as the hinge characteristic.

上記表１〜表２に結果を示した。
表１の実施例より、本発明のスチレン系難燃性樹脂組成物は、難燃性、ヒンジ特性がバランス良く改良されていることがわかる。

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

However, the styrenic flame retardant resin composition obtained in the comparative example of Table 2 that does not satisfy the provisions of the present invention is excellent in both flame retardancy and hinge characteristics, but both characteristics are excellent. You can see that there is never.

For example, when (B) a flame retardant, (C) a flame retardant aid, and (D) a higher fatty acid metal salt are not added, the flame retardancy is less than the V-2 level (Comparative Example 1). When (B) a flame retardant and (C) a flame retardant aid are not added, the flame retardancy is less than the V-2 level (Comparative Example 2). In addition, when (C) flame retardant aid and (D) higher fatty acid metal salt are present in the specified amount, and (B) flame retardant is added, if the added amount is less than the specified amount, the flame retardancy is V-2. It does not reach the level (Comparative Example 3), and conversely, if the amount of the flame retardant (B) is added more than the specified amount, the hinge characteristics are lowered (Comparative Example 4). In addition, even if (B) flame retardant, (C) flame retardant aid, (D) higher fatty acid metal salt is added in a specified amount, (B) flame retardant having a melting point of 300 ° C. is used. If this is the case, the deterioration of the hinge characteristics is extremely undesirable (Comparative Examples 5 and 6). Further, when (B) a flame retardant and (D) a higher fatty acid metal salt are present in a specified amount, and (C) a flame retardant aid is added, if the added amount is less than the specified amount, the flame retardancy is V-2. It does not reach the level (Comparative Example 7), and conversely, if (C) the flame retardant aid is added in excess of the specified amount, the hinge characteristics are deteriorated (Comparative Example 8). Moreover, even if (B) a flame retardant and (C) a flame retardant aid are present in a specified amount and (D) a higher fatty acid metal salt is added, if the added amount is less than the specified amount, the hinge characteristics are significantly reduced ( On the contrary, when (D) higher fatty acid metal salt is added more than the prescribed amount, the flame retardancy does not reach the V-2 level (Comparative Example 10).

Since the styrene-based flame retardant resin composition of the present invention is excellent in flame retardancy and hinge characteristics, it is advantageous to use it in OA equipment and home appliance parts having a hinge.

Claims (6)

(A) 100 parts by mass of rubber-modified polystyrene resin, (B) 7-15 parts by mass of a brominated flame retardant having a melting point exceeding 300 ° C., (C) 1-6 parts by mass of a flame retardant aid, and (D) A styrene-based flame retardant resin composition having excellent hinge characteristics, comprising 0.1 to 1.5 parts by mass of a higher fatty acid metal salt. The styrene flame retardant resin composition having excellent hinge characteristics according to claim 1, wherein the rubber content in the styrene flame retardant resin composition is 8.0% by mass or more. (B) The brominated flame retardant is 1,2-bis (pentabromophenyl) ethane, The styrene flame retardant resin composition having excellent hinge characteristics according to claim 1 or 2. (C) The flame retardant auxiliary agent is antimony trioxide, The styrenic flame retardant resin composition having excellent hinge characteristics according to any one of claims 1 to 3. (D) The higher fatty acid metal salt is zinc stearate, The styrenic flame retardant resin composition having excellent hinge characteristics according to any one of claims 1 to 4. A molded article obtained by molding the styrene-based flame retardant resin composition having excellent hinge characteristics according to any one of claims 1 to 5.

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