JPH0689205B2 - Flame-retardant resin composition with excellent moldability - 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 thermoplastic resin with phenol / aldehyde resin, organic nitrogen compound, and organic phosphorus compound, ABS resin with red phosphorus, melamine, and thermal crosslinking curing A flame-retardant resin composition (Japanese Unexamined Patent Publication No. 61-291643) containing a water-soluble resin 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 comprising polyphenylene ether, a 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 Problem] The inventors of the present invention have conducted extensive studies to improve the fluidity of a rubber-modified vinyl aromatic resin typified by HIPS and a flame-retardant resin composed of polyphenylene ether and red phosphorus. The inventors have found that a resin composition comprising a rubber-modified vinyl aromatic resin having a specific composition, a small amount of polyphenylene ether, and red phosphorus can efficiently solve the above problems, and 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 100 parts by weight of C), and 1 to 15 parts by weight of red phosphorus. The composition, wherein the matrix portion of the rubber-modified vinyl aromatic resin is 70 to 99% by weight of a vinyl aromatic monomer residue, and a (meth) acrylic acid ester monomer selected from the following group: 1) Acrylic ester in which the alkyl group of the ester moiety has a carbon number in the range of 3 to 10 2) One or more residues 1 or more of methacrylic acid ester in which the alkyl group of the ester moiety has a carbon number in the range of 8 to 20 A flame-retardant resin composition comprising 10% by weight and 0 to 30% by weight of a vinyl monomer residue copolymerizable therewith.

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

The resin composition of the present invention comprises a resin component composed of the rubber-modified vinyl aromatic resin referred to as the component A and the polyphenylene ether referred to as the component B, and red phosphorus as the flame retardancy-imparting component. The ratio of the B component in the components is in the range of 3 to 25% by weight. If the proportion of the component B is less than 3% by weight, the flame retardancy is not sufficient, and if it exceeds 25% by weight, the moldability is remarkably inferior.
Not within the scope of the 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 composed of a vinyl aromatic polymer described later, and is generally rubber-like. The polymer is dissolved in a vinyl monomer containing a vinyl aromatic monomer as a main component (and a liquid containing an inert solvent),
It is obtained by carrying out bulk polymerization, bulk suspension polymerization, or solution polymerization with stirring to precipitate a rubber-like polymer and to make it into particles.

In the present invention, the matrix portion of the rubber-modified vinyl aromatic resin is 70 to 99% by weight of a vinyl aromatic monomer residue, and a (meth) acrylic acid ester monomer selected from the following group: 1) ester Acrylic ester in which the carbon number of the alkyl group of the portion is in the range of 3 to 10 2) One or more residues 1 to 10 of methacrylic acid ester in which the carbon number of the alkyl group of the ester portion is in the range of 8 to 20 It is necessary to be composed of 0 to 30% by weight and vinyl monomer residues copolymerizable therewith.

When the amount of the vinyl aromatic monomer residue is less than 70% by weight, the heat distortion temperature of the finally obtained resin composition is lowered, and when it exceeds 99% by weight, the fluidity is poor. It becomes a thing. When the amount of the (meth) acrylic acid ester monomer residue is less than 1% by weight, the fluidity of the finally obtained resin composition is inferior,
If it exceeds 10% by weight, the heat distortion temperature will decrease,
Moreover, the compatibility of the A component and the B component becomes poor,
The mechanical properties of the finally obtained resin composition will deteriorate.

Further, when the above-mentioned (meth) acrylic acid ester monomer is an acrylic acid ester monomer, it is necessary that the carbon number of the alkyl group of the ester portion thereof is within the range of 3 to 10, In the case of an acid ester monomer, it is necessary that the alkyl group of the ester portion thereof has a carbon number in the range of 8 to 20. If the above requirements regarding the number of carbon atoms of the alkyl group of the ester portion of the (meth) acrylic acid ester monomer are not satisfied, the fluidity of the finally obtained resin composition will not be improved and cured. These (meth) acrylic acid ester monomers have a homopolymer glass transition temperature of −80 to −
Characterized by being in the range of 30 ° C.

Another advantage of improving the fluidity by using the above (meth) acrylic acid ester monomer is a defective phenomenon that an oily substance is deposited on the surface of a mold or a molded product, which is observed when a conventional plasticizer is added. (It is well known to those skilled in the art as a mold sweat.).

Specific examples of the (meth) acrylic acid ester satisfying the above requirements include propyl acrylate, butyl acrylate, hexyl acrylate, hebutyl acrylate, and 2-methacrylate.
Acrylic esters such as ethylheptyl acrylate, 2-ethylhexyl acrylate, 2--ethylbutyl acrylate, dodecyl acrylate, n-decyl methacrylate, lauryl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, stearyl methacrylate, etc. Acrylic acid esters can be mentioned, but propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate are particularly preferable.

Next, as the vinyl aromatic monomer, in addition to styrene, a nucleus of o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4 dimethylstyrene, ethylstyrene, p-tertiarybutylstyrene, etc. Alkyl-substituted styrene, α-methylstyrene, α-alkyl-substituted styrene such as α-methyl-p-methylstyrene and the like can be mentioned, but styrene is typical. These are the 2
You may use together 1 or more types.

The matrix portion of the vinyl aromatic polymer of the present invention contains a vinyl monomer copolymerizable with the vinyl aromatic monomer and the (meth) acrylic acid ester monomer, if necessary. , 30 wt% can be included in the upper limit. Examples of these vinyl monomers include acrylonitrile, methyl methacrylate, N-phenylmaleimide, and other vinyl monomers. When the content of these monomers exceeds 30% by weight, the impact strength of the finally obtained resin composition is lowered, which is not preferable.

Examples of the rubber-like polymer include polybutadiene, styrene / butadiene copolymer, polyisoprene, butadiene / isoprene copolymer, natural rubber, ethylene / propylene copolymer, and the like.
Polybutadiene and styrene-butadiene copolymer are preferred. As the polybutadiene, either low cis polybutadiene or high cis polybutadiene can be preferably used. Further, as these rubber-like polymers, those in which a part of the unsaturated bond portion is hydrogenated can be used.

There is no particular limitation on the content of the rubber-like polymer in the rubber-modified vinyl aromatic resin, but generally 4 to 15% by weight,
It is more preferably 6 to 10% by weight.

Next, the average particle size of the rubber particles in the rubber-modified vinyl aromatic resin is generally controlled in the range of 0.5 to 6.0 μm. The rubber particle size is a transmission electron microscope photograph taken by an ultrathin section method of a rubber-modified vinyl aromatic resin,
The diameter of 000 rubber particles is calculated and calculated according to the following formula.

However, Di: diameter of dispersed rubber particles.

 ni: the number of rubber particles of diameter Di.

Further, the gel content (toluene-insoluble matter) in the rubber-modified vinyl aromatic resin is adjusted to 15 to 40% by weight in the usual method,
More preferably, it is 20 to 35% by weight.

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 is composed of a binding unit represented by the following general formula and has a reduced viscosity (0.5 g / dl, chloroform solution, measured at 30 ° C.). , A homopolymer in the range of 0.15 to 0.70 dl / g, and more preferably in the range of 0.20 to 0.60 dl / g and /
Or a copolymer; (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. ) 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.

There is no particular limitation on the method of blending the above components A to C, 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: Preparation of Rubber Modified Vinyl Aromatic Resin] [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 (NF-35A, Asahi Kasei Corporation) ・ Styrene: 72.0 parts by weight ・ Butyl acrylate: 5.0 parts by weight ・ Ethylbenzene: 15.0 parts by weight ・ α-Methylstyrene dimer: 0.16 parts by weight ・ Stearyl 3- (3,5-Diterjaributyl-4-hydroxyphenyl) -propionate: 0.10 parts by weight Next, the above stock solution for polymerization was continuously fed to a multi-stage reactor equipped with a stirring 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 of 2.5 μm and the final reaction product was 80% by weight. 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 composition analysis of the matrix portion of the obtained rubber-modified vinyl aromatic resin, styrene was 95.4% by weight and butyl acrylate was 5.6% by weight. The gel content determined as the toluene insoluble content was 28% by weight, and the reduced viscosity of the matrix part was 0.72 dl / g.

Reference Example 2-Rubber Modified Vinyl Aromatic Resin S2 In the same manner as in Reference Example 1 except that the amount of butyl acrylate added was increased and the stirring number of the reactor was increased, the average particle size of the rubber particles was 2.2. Micron, rubber content 10% by weight,
The composition of the matrix part was 92.6% by weight of styrene, 7.4% by weight of butyl acrylate, the gel content was 29% by weight as a toluene insoluble content, and the reduced viscosity of the matrix part was 0.74.
A dl / g rubber-modified vinyl aromatic resin was obtained.

[Reference Example 3-Rubber-modified vinyl aromatic resin S3] In Reference Example 1, except that butyl acrylate was not added, the average particle diameter of the rubber particles was 2.1 μm,
A rubber-modified polystyrene having a rubber content of 10% by weight, a gel content of 29% by weight as a toluene insoluble content, and a reduced viscosity of a matrix portion of 0.74 dl / g was obtained.

Reference Example 4-Rubber Modified Vinyl Aromatic Resin S4 In the same manner as in Reference Example 1 except that the amount of butyl acrylate added was increased and the stirring number of the reactor was increased, the average particle size of the rubber particles was 2.4. Micron, rubber content 10% by weight,
The composition of the matrix part was 89.4% by weight of styrene, 10.6% by weight of butyl acrylate, the gel content was 28% by weight as a toluene insoluble content, and the reduced viscosity of the matrix part was 0.72.
A dl / g rubber-modified vinyl aromatic resin was obtained.

[Reference Example 5-Rubber-modified vinyl aromatic resin S5] In the same manner as in Reference Example 1, except that 2-ethylhexyl acrylate was used instead of butyl acrylate, the average particle diameter of the rubber particles was 2.2 μm, and the rubber content was 10 % By weight, the composition of the matrix part is 95.6% by weight of styrene,
A rubber-modified vinyl aromatic resin having 4.4% by weight of 2-ethylhexyl acrylate, a gel content of 30% by weight as a toluene insoluble content, and a reduced viscosity of 0.74 dl / g of a matrix portion was obtained.

[Reference Example 6-Rubber-modified vinyl aromatic resin S6] In the same manner as in Reference Example 1 except that lauryl methacrylate was used instead of butyl acrylate, the average particle diameter of the rubber particles was 2.5 μm, and the rubber content was 10% by weight. , The composition of the matrix portion was 95.4% by weight of styrene, 4.6% by weight of lauryl methacrylate, the gel content was 27% by weight as a toluene insoluble content, and the reduced viscosity of the matrix portion was 0.72dl.
A rubber-modified vinyl aromatic resin of / g was obtained.

Reference Example 7-Rubber Modified Vinyl Aromatic Resin S7 In the same manner as in Reference Example 1 except that methyl methacrylate was used instead of butyl acrylate, the average particle diameter of the rubber particles was 2.1 μm and the rubber content was 10% by weight. The composition of the matrix portion was 93.7% by weight of styrene, 6.3% by weight of methyl methacrylate, 29% by weight of gel content obtained as a toluene insoluble content, and a rubber-modified vinyl aromatic resin having a reduced viscosity of 0.70 dl / g of the matrix portion was obtained. .

[Reference Example 8-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 6 and Comparative Examples 1 to 8] Rubber-modified vinyl aromatic resin and PPE prepared in Reference Example
And red phosphorus (Rin Chemical Industry Co., Ltd., Novarred # 120,
Red phosphorus content (85% by weight) was blended in the proportions shown in Tables 1 and 2 and kneaded with a twin-screw extruder to obtain pellets of the resin composition. (In Comparative Example 8, mineral oil was further blended in addition to the above components.) Then, a test piece was prepared with an injection molding machine, and a mechanical physical property, a flammability test and a mold sweat test were performed.
The test followed the following method.

・ Izod impact strength: ASTM D-256 (with notch) ・ Flexural modulus: ASTM D-790 ・ Melt flow rate: ISO-R1133 (200%, 5kg load) ・ Combustibility: UL-94 (1/12 inch) -Mold switch: ASTM D-638 dumbbell test pieces are continuously injection-molded 50 times, and the deposition state of oily substances on the test pieces is visually observed. The case of precipitation is regarded as a defect.

The results are shown in Tables 1 and 2.

[Example 7] 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 230 ° 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 9] The same operation as in Example 7 was performed except that the resin composition of Comparative Example 1 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

[Effects of the Invention] As is clear from Tables 1 and 2, the resin composition of the present invention is excellent in impact strength, flame retardancy and fluidity,
Moreover, there is no precipitation of oily substances on the surface of the mold or the molded product, which is useful as a molding material. 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) 1 to 15 parts by weight of red phosphorus is added to 100 parts by weight of A) 97 to 75 parts by weight of rubber-modified vinyl aromatic resin and 3 to 25 parts by weight of B) polyphenylene ether. In the resin composition, the matrix portion of the rubber-modified vinyl aromatic resin is 70 to 99% by weight of a vinyl aromatic monomer residue, and a (meth) acrylic acid ester monomer selected from the following group: 1) Ester Acrylic ester in which the carbon number of the partial alkyl group is in the range of 3 to 10 2) One or more residues 1 to 10 of methacrylic acid ester in which the alkyl group of the ester portion is in the range of 8 to 20 A flame-retardant resin composition comprising 0 to 30% by weight and a vinyl monomer residue copolymerizable therewith.