JPH0689209B2 - Flame-retardant resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin composition having excellent flame retardancy. More specifically, it relates to a flame-retardant styrene resin composition containing no halogen compound.

[Problems to be Solved by Conventional Techniques and Inventions] Rubber-modified vinyl aromatic resins represented by HIPS are excellent in moldability and dimensional stability, as well as in impact resistance, rigidity,
Due to its excellent electrical insulation properties, it has come to be used in a wide variety of fields including home electric appliance parts and OA equipment parts.

For plastic materials used in such fields in recent years,
Due to safety issues, the demand for flame retardancy is increasing,
Various flame retardancy standards have been established. Although various methods have been devised as a method for imparting flame retardancy to a resin having difficulty, generally, a halogen compound such as a bromine compound having a high flame retardant effect and, if necessary, antimony oxide. Is added to the resin. As the bromine compound, nuclear bromine-substituted aromatic compounds such as decabromodiphenyl ether, tetrabromobisphenol A, and brominated phthalimide are known, but the method by adding these flame retardants gives excellent flame retardancy. Though
The impact strength and the heat denaturation temperature are lowered, and in some cases, the flame retardant bleeds out on the surface of the resin molded product to deteriorate the appearance of the molded product. Furthermore, when the resin is molded, the halogen compounds are thermally decomposed to generate a toxic gas to the human body and corrode the mold and the screw.

For this reason, methods of flame retarding without using halogen compounds have been investigated. As such a method, a method of adding a hydrated metal compound such as aluminum hydroxide or magnesium hydroxide to a resin is known, but in order to obtain sufficient flame retardancy, a large amount of the hydrated metal compound is added. However, there is a drawback that the original properties of the resin are lost.

On the other hand, as a method not using such a hydrated metal compound,
Flame-retardant resin composition (US Pat. No. 4,632,946) prepared by blending a thermoplastic resin with a phenol / aldehyde resin, an organic nitrogen compound and an organic phosphorus compound, and ABS resin with red phosphorus, melamine, and a heat-crosslinking curable resin. A flame-retardant resin composition (JP-A-61-291643) is disclosed. However, such a method requires a large amount of various kinds of additives and has a problem that the original properties of the resin are impaired.

On the other hand, US Pat. No. 3,663,654 discloses a flame-retardant resin composition containing polyphenylene ether, a rubber-modified styrene resin and red phosphorus. The above resin composition is a useful flame-retardant resin material that does not use a halogen compound, but since it contains a large amount of polyphenylene ether having low fluidity, there is a problem that the moldability of the resin composition is poor.

[Means for Solving the Problems] The inventors of the present invention have diligently studied to solve the above problems related to a flame-retardant resin composed of a rubber-modified vinyl aromatic resin typified by HIPS and polyphenylene ether and red phosphorus. The inventors have found that the above problem can be efficiently solved by using a rubber-modified vinyl aromatic resin having a specific structure, and have completed the present invention.

That is, the present invention comprises: A) 97 to 75 parts by weight of rubber-modified vinyl aromatic resin, B) 3 to 25 parts by weight of polyphenylene ether, and C) 1 to 15 parts by weight of red phosphorus D) Mineral oil 0 to A resin composition comprising 10 parts by weight of the rubber-modified vinyl aromatic resin, wherein the rubber-modified vinyl aromatic resin is in the range of 3.0 to 6.0 μm based on the total weight of the rubber particles dispersed in the matrix. A flame-retardant resin composition, characterized in that the proportion is 60% by weight or more.

The contents of the present invention will be described below step by step.

The resin composition of the present invention is added with a resin component composed of the rubber-modified vinyl aromatic resin referred to as the component A and the polyphenylene ether referred to with the component B, red phosphorus as the flame retardancy-imparting component, and if necessary. Although it is composed of mineral oil as a fluidity promoter, the proportion of B component in the above resin component is in the range of 3 to 25% by weight. If the proportion of B component is less than 3% by weight, the flame retardance is not sufficient and it is 25% by weight.
If it exceeds the above range, the moldability is remarkably inferior and does not belong to the scope of the present invention. The more preferable range of the component B is 5 to 15% by weight.

The rubber-modified vinyl aromatic resin as the component A is a polymer in which a rubber-like polymer is dispersed in particles in a matrix made of a vinyl aromatic polymer, and generally, the rubber-like polymer is a vinyl-based polymer. Obtained by dissolving in an aromatic monomer (and a liquid containing an inert solvent), performing bulk polymerization, bulk suspension polymerization, or solution polymerization with stirring to precipitate a rubber-like polymer and granulate it. .

As the above vinyl aromatic monomer, in addition to styrene,
Nuclear alkyl-substituted styrenes such as o-methyl styrene, p-methyl styrene, m-methyl styrene, 2,4 dimethyl styrene, ethyl styrene, p-tertiary butyl styrene, α
-Methylstyrene, α-alkyl-substituted styrene such as α-methyl-p-methylstyrene, and the like,
A typical example is styrene. These may be used in combination of two or more thereof.

The rubber polymer means polybutadiene (high cis polybutadiene, low cis polybutadiene), styrene
Examples thereof include butadiene copolymers (random or block copolymers thereof), polyisoprene, butadiene / isoprene copolymers, natural rubber, and the like, with polybutadiene and styrene / butadiene copolymers being particularly preferable.

Conventionally, in order to maximize impact strength, the dispersed particle size of rubber-modified polystyrene, which has been typified by rubber-modified vinyl aromatic resin, is, for example, Angevanthemie (ANGEWA).
NDTE CHEMIE) Vol. 20, No. 4 (1981) p. 352, FIG. 11, it was customary to adjust to a range of 1 to 3 microns. In the rubber-modified vinyl aromatic resin referred to as the above-mentioned component A of the present invention, the particle diameter of the dispersed rubber particles must be within a specific range different from what is taught by the above-mentioned documents and the like. That is, the rubber-modified vinyl aromatic resin of the present invention accounts for 3.0 to 6.0 of the total weight of the dispersed rubber particles.
The proportion of rubber particles in the micron range must be above 60% by weight. The proportion of rubber particles in the above range is 60
If the amount is less than 10% by weight, the final resin composition will be easily melted and dripped at the time of combustion, and underwriters lab light lis incorporated (UNDER
It becomes difficult to meet the requirement of V-O, which is the higher flammability rank of UL-94 standard defined by WRITERS LABOLATORIES INC.), Or the impact strength becomes poor. The proportion of rubber particles in the above range is more preferably 80% by weight.
That is all.

The ratio of the rubber particles in the range of 3.0 to 6.0 microns to the total weight of the dispersed rubber particles is taken by taking a transmission electron microscope photograph by the ultrathin section method of the rubber-modified vinyl aromatic resin, and 1,000 rubber particles are taken. The diameter of the

However, f: Proportion of rubber particles in the range of 3.0 to 6.0 microns in the total weight of dispersed rubber particles.

Di: Diameter of dispersed rubber particles.

ni: the number of rubber particles of diameter Di.

Dj: Diameter of rubber particles in the range of 3.0-6.0 microns.

nj: the number of rubber particles of diameter Dj.

When adjusting the rubber-modified vinyl aromatic resin, as a general means for satisfying the above requirements regarding the dispersed rubber particles, bulk polymerization, bulk suspension polymerization, or solution polymerization is performed, and a rubber-like polymer is used. Precipitation, stirring number at the time of forming particles, or control of shear rate can be mentioned,
The method described in JP-A-59-105013 can be adopted in order to more efficiently achieve the object of the present invention by making the distribution range of the rubber particle diameter narrower. In this method, a liquid obtained by dissolving a rubber-like polymer in a vinyl aromatic monomer is continuously supplied to a reactor so that the vinyl-aromatic monomer does not exceed a conversion rate at which the rubber-like polymer becomes particles. Continuous polymerization of the monomer,
On the other hand, independently of this, the vinyl aromatic monomer is continuously supplied to another reactor to continuously polymerize to make a liquid during the polymerization of the vinyl aromatic monomer and Polymer /
The weight ratio with the rubbery polymer is 2.0 to 4.5 (preferably 2.5 to
After mixing and stirring so as to obtain 3.5), a rubbery polymer is forcibly instantly precipitated and made into particles, and then polymerization is continued to continuously obtain a rubber-modified vinyl aromatic resin. According to this method, the rubber particles are different from the usual method in that the rubber-like polymer is forcibly precipitated instantaneously and made into particles, so that the distribution range of the rubber particle diameter becomes extremely narrow, and the object of the present invention is to achieve the object. Suitable to achieve.

Next, the content of the rubbery polymer in the component A can be appropriately adjusted, but it is generally in the range of 5 to 15% by weight, and the impact strength and molding process of the finally obtained resin composition are From the viewpoint of the balance of sex, the range of 8 to 12% is more preferable.

Further, the gel content (toluene-insoluble matter) in the component A due to the toluene solvent can be appropriately adjusted within the range of 20 to 40% by weight according to a conventional method.

Further, the reduced viscosity of the matrix portion of the rubber-modified vinyl aromatic resin excluding the rubber-like polymer portion is 0.40 to 1.20 of the usual value.
Controlled in the range of dl / g, but preferably 0.50-0.80 dl / g
Is the range.

Next, the polyphenylene ether (hereinafter abbreviated as PPE) referred to as the component B of the present invention means a bonding unit represented by the following general formula: (Here, R ₁ , R ₂ , R ₃ and R ₄ are hydrogen, carbon hydrogen,
Alternatively, it is selected from the group consisting of substituted hydrocarbon groups and may be the same or different from each other. ), The reduced viscosity (0.5 g / dl, chloroform solution, measured at 30 ° C.) is in the range of 0.15 to 0.70 dl / g, more preferably 0.20 to 0.
It is a homopolymer and / or a copolymer in the range of 60 dl / g.

A specific example of this PPE is poly (2,6-dimethyl-
1,4-phenylene ether), a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol and the like are preferable, and among them, poly (2,6-dimethyl-1,4-phenylene ether) is preferable. preferable.

The method for producing such PPE is not particularly limited as long as it can be obtained by a known method.
Using a complex of a cuprous salt and an amine as a catalyst according to the method described in 3,306,874, it can be easily produced by, for example, oxidative polymerization of 2,6 xylenol.In addition, U.S. Pat.No. 3,306,875 Patent No.
It can be easily produced by the methods described in 3,257,357, U.S. Pat. No. 3,257,358, Japanese Patent Publication No. 52-17880 and Japanese Patent Publication No. 50-51197.

Next, in the present invention, red phosphorus is used as the third component. The red phosphorus may be in the form of fine particles, but from the viewpoint of handling, it is preferable that the surface is coated with resin, mineral oil, or metal hydrate.

It is necessary that the amount of the red phosphorus compounded is 1 to 15 parts by weight with respect to 100 parts by weight of the resin component consisting of the components A and B. If the blending amount is less than 1 part by weight, sufficient flame retardancy cannot be obtained. On the other hand, if the blending amount exceeds 15 parts by weight, the impact strength, moldability and appearance of the finally obtained composition will be poor. The preferred amount is 2 to 10 parts by weight, and the more preferred amount is 3 to 8
Parts by weight.

In the present invention, the above A), B), and C) components, if necessary, D) mineral oil, and A) and B) both components in total 100
An upper limit of 10 parts by weight can be added to parts by weight.
If the amount of mineral oil added exceeds 10 parts by weight, the heat distortion temperature of the finally obtained resin composition will decrease, and an oily substance will accumulate on the mold surface during molding, which is not preferable. More preferable amount of mineral oil is
3 to 6 parts by weight. As the mineral oil, a commonly used mineral oil can be used. Initial boiling point at 10 mmHg is 21
It is more preferably 0 ° C or higher. As a mineral oil satisfying such conditions, for example, Cristol 352, which is a mineral oil manufactured by Esso Oil Co., Ltd., can be cited. Further, when the rubber-modified vinyl aromatic resin as the component B is polymerized with all or a part of the mineral oil, it is added to the polymerization liquid to prepare a rubber-modified vinyl aromatic resin containing mineral oil, The content of mineral oil in the finally obtained resin composition can also be adjusted.

There is no particular restriction on the method of blending the above components A to C (or A to C and D), and the above components may be melt mixed by a conventional mixer such as an extruder, a kneader or a Banbury mixer. At this time, if possible, it is preferable that the A component and the B component are kneaded in advance before the C component is mixed, and then the C component is added and kneaded so that the B component is uniformly dispersed. .

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Example] In the following examples and comparative examples, the following samples were used.

[Reference Example 1: Rubber-modified vinyl aromatic resin, S1] A polymerization stock solution having the following composition was prepared.

・ Polybutadiene rubber: 8.0 parts by weight (Asahi Kasei Kogyo NF-35A) ・ Styrene: 77.0 parts by weight ・ Ethylbenzene: 15.0 parts by weight ・ α-Methylstyrene dimer: 0.06 parts by weight ・ Stearyl 3- (3,5-ditertiary) Butyl-4-hydroxyphenyl) -propionate: 0.10 parts by weight Then, the above polymerization stock solution was continuously fed to a multistage reactor equipped with a stir bar to carry out polymerization. The average particle size of rubber particles is
The polymerization temperature and the number of agitation were adjusted so that the solid content concentration in the final reactor was 3.5 μm and was 80 wt%. Subsequently, the polymerization liquid was introduced into a devolatilizer to obtain a rubber-modified vinyl aromatic resin having a rubber content of 10% by weight.

As a result of analyzing the obtained rubber-modified vinyl aromatic resin, the ratio of the rubber particles in the range of 3.0 to 6.0 microns to the total weight of the dispersed rubber particles was 63% by weight. The reduced viscosity of the matrix was 0.75 dl / g and the gel content was 35% by weight.

[Reference Example 2: Rubber-modified vinyl aromatic resin, S2] In the same manner as in Reference Example 1, except that the stirring number was increased, the average particle diameter of the rubber particles was 1.5 microns, and the rubber content was 10% by weight.
To obtain a rubber-modified vinyl aromatic resin.

As a result of analyzing the obtained rubber-modified vinyl aromatic resin, the ratio of the rubber particles in the range of 3.0 to 6.0 microns to the total weight of the dispersed rubber particles was 36% by weight. The reduced viscosity of the matrix was 0.75 dl / g and the gel content was 30% by weight.

[Reference Example 3: Rubber-modified vinyl aromatic resin, S3] A polymerization stock solution of the first stream having the following composition was continuously fed at a rate of 2.0 / h to a laminar flow type reactor having an inner volume of 2 equipped with a stirring rod. Liquid polymerization was carried out.

・ Polybutadiene rubber: 12.0 parts by weight (Asahi Kasei Kogyo NF-35A) ・ Styrene: 73.0 parts by weight ・ Ethylbenzene: 15.0 parts by weight ・ 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane : 0.02 parts by weight ・ α-methylstyrene dimer: 0.06 parts by weight ・ Stearyl 3- (3,5-ditertiarybutyl-4-hydroxyphenyl) -propionate: 0.15 parts by weight Control the temperature inside the reactor and generate at the reactor outlet The polystyrene concentration was controlled to be 6 to 8% by weight. The polymerization liquid collected from the reactor outlet was insoluble in dimethylformaldehyde, and the polybutadiene rubber was not formed into particles.

On the other hand, a direct-coupled two-layer type laminar flow reactor with a stirring rod each having an inner volume of 7 was continuously fed with a second stream of polymerization stock solution having the following composition at a rate of 1.0 / h. Polymerization was carried out.

・ Styrene: 85.0 parts by weight ・ Ethylbenzene: 15.0 parts by weight ・ α-Methylstyrene dimer: 0.05 parts by weight Adjust the temperature inside each reactor so that the concentration of polystyrene produced at the outlet of the second tank reactor is 42 to 45% by weight. Controlled.

Subsequently, the above-mentioned first flow and second flow are added to the internal volume 1
Was continuously fed to the mixer. The solid content (total of polybutadiene and generated polystyrene) of the polymerization liquid collected from the mixer outlet is 35 to 37% by weight, and the polymerization liquid is
It was soluble in dimethylformamide and the polybutadiene in the first stream was particulate.

The above polymerization solution was continuously introduced into a laminar flow reactor with a stirring rod having an inner volume of 7 to continue the polymerization. The solid content concentration at the reactor outlet was controlled to be 80% by weight. Then, it was sent to a devolatilizer to obtain rubber-modified vinyl aromatic resin pellets having a rubber content of 10% by weight and an average rubber particle diameter of 3.8 μm.

As a result of analyzing the obtained rubber-modified vinyl aromatic resin, the ratio of the rubber particles in the range of 3.0 to 6.0 microns to the total weight of the dispersed rubber particles was 86% by weight. The reduced viscosity of the matrix was 0.72 dl / g and the gel content was 30% by weight.

[Reference Example 4: Rubber-modified vinyl aromatic resin, S4] A rubber-modified vinyl aromatic resin was prepared in the same manner as in Reference Example 3 except that the number of agitators of the mixer for mixing the first and second streams was reduced. Obtained.

As a result of analyzing the obtained rubber-modified vinyl aromatic resin, the average particle diameter of the dispersed rubber particles was 6.5 microns, and the ratio of the rubber particles in the range of 3.0 to 6.0 microns to the total weight of the dispersed rubber particles was 49% by weight. there were. The reduced viscosity of the matrix was 0.72 dl / g and the gel content was 32% by weight.

[Reference Example 5-Preparation of PPE] After the inside of a stainless steel reactor having an oxygen blowing port at the bottom of the reactor and having a cooling coil and stirring blades inside was sufficiently replaced with nitrogen, cupric bromide 54.8 g, di-n-butylamine 1110 g, and toluene 20, n-butanol 16
2,6-xylenol 8.75 in a mixed solvent of methanol and methanol 4.
kg was melted and charged into the reactor. Continue to blow oxygen into the reactor while stirring and control the internal temperature to 30 ℃.
Polymerization was carried out for 0 minutes. After the completion of the polymerization, the precipitated polymer was separated by filtration, a methanol / hydrochloric acid mixture was added to decompose the residual catalyst in the polymer, and the polymer was thoroughly washed with methanol and dried to obtain a powdery PPE. Reduced viscosity is 0.55d
It was l / g.

[Examples 1 to 4 and Comparative Examples 1 to 6] Rubber-modified vinyl aromatic resin prepared in Reference Example, PPE,
Red Phosphorus (Rin Kagaku Kogyo Co., Noba Red # 120, Red Phosphorus Content 85% by Weight) and Mineral Oil (Esso Oil Co., Ltd. Mineral Oil, Cristol 352.10 mmHg
(Initial boiling point at 237 ° C.) in the ratio shown in Table 2 and kneaded with a twin-screw extruder to obtain pellets of the resin composition. Next, a test piece was prepared with an injection molding machine, and a mechanical physical property and flammability test was performed. The physical properties and flammability tests were according to the following methods.

・ Izod impact strength: ASTM D-256 (with notch) ・ Melt flow rate: ISO-R1133 (200 ° C, 5kg load) ・ Combustibility: UL-94 (1/12 inch) The results are shown in Table 1.

[Example 5] Using the resin composition of Example 1, an injection molding machine (IS800B-75 manufactured by Toshiba Machine Co., Ltd.) under the conditions of a cylinder temperature of 250 ° C and a mold temperature of 45 ° C, an average wall thickness. A molded body of a 3 mm TV receiver outer shell part was obtained.

[Comparative Example 7] The same operation as in Example 5 was carried out except that the resin composition of Comparative Example 3 was used instead of the resin composition of Example 1, but the fluidity of the resin was poor and a molded article was obtained. Couldn't get

[Effect of the Invention] As is clear from Table 1, the resin composition of the present invention is excellent in impact strength, flame retardancy and fluidity, and is useful as a material for injection molding. Further, since the resin composition of the present invention is particularly excellent in fluidity, it is suitable for obtaining a large-sized molded product such as an outer shell of a television receiver.

Claims (1)

[Claims] 1. A) 97 to 75 parts by weight of rubber-modified vinyl aromatic resin, B) 3 to 25 parts by weight of polyphenylene ether, to 100 parts by weight in total, C) 1 to 15 parts by weight of red phosphorus D) Mineral oil 0 to In a resin composition containing 10 parts by weight of the rubber-modified vinyl aromatic resin, the ratio of the rubber particles in the range of 3.0 to 6.0 μm based on the total weight of the rubber particles dispersed in the matrix. A flame-retardant resin composition, which is 60% by weight or more.