JPH0689208B2 - Impact resistant 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 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 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 low flowability polyphenylene ether, the moldability of the resin composition is poor, and the melting temperature is further increased. When the polyphenylene ether and the rubber-modified styrene-based resin, which have a high temperature, are melt-mixed, the rubber-modified styrene-based resin is thermally deteriorated, and the impact strength of the finally obtained resin composition tends to be low. .

[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-mentioned problems can be efficiently solved by using, as the above-mentioned rubber-modified styrene-based resin, one modified with a specific rubber-like polymer, 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 flame-retardant resin comprising a resin composition containing 10 parts by weight, wherein the rubber-modified vinyl aromatic resin is modified with a partial hydrogenation product of a butadiene-based polymer. A composition is provided.

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. 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-modified vinyl aromatic resin used in the present invention is reinforced with one obtained by hydrogenating a part of the unsaturated bond portion of the butadiene-based polymer (hereinafter, each term of partially hydrogenated rubber is used). It is necessary to be.

Examples of the butadiene-based polymer include polybutadiene (high cis polybutadiene, low cis polybutadiene), styrene / butadiene copolymer (random or block copolymer thereof), polyisoprene, butadiene / isoprene copolymer, natural rubber and the like. However, polybutadiene and styrene-butadiene copolymer are particularly preferable.

The butadiene-based polymer is produced by a known method, for example, a polymerization method using an organic lithium catalyst, a polymerization method using a Ziegler-based catalyst containing an organic compound such as nickel, cobalt, or titanium as a main component, and a rare earth metal compound such as neodymium. A polymerization method using a catalyst as a component, a polymerization method using a peroxide, etc. may be used.

The partially hydrogenated rubber referred to in the present invention shows the above-mentioned butadiene-based polymer in a known method, for example, in JP-A-52-41890, JP-A-59-133203, and JP-A-60-220147. It is obtained by partial hydrogenation according to the method described above. The hydrogenation rate of the partially hydrogenated rubber is preferably in the range of 10 to 80%, more preferably 20 to 60%, based on the total double bonds of the butadiene-based polymer. When the hydrogenation rate is less than 10%, the impact resistance of the finally obtained resin composition is not sufficient, and when it exceeds 80%, the impact resistance is not further improved and the economy is small. Not relevant.

The content of the butadiene-based polymer in the rubber-modified vinyl aromatic resin is generally in the range of 5 to 20% by weight, but the impact resistance and molding processability of the finally obtained resin composition are considered. Therefore, the range of 8 to 12% by weight is preferable.

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.

Furthermore, the average particle size of the rubber particles in the rubber-modified vinyl aromatic resin is in the range of 0.5 to 6.0 microns, more preferably 0.
Controlled in the range of 8 to 4.0 microns. The diameter of the rubber particles is obtained by taking a transmission electron micrograph of a rubber-modified vinyl aromatic resin by an ultrathin section method, obtaining the diameter of 1,000 rubber particles, and then obtaining the following formula.

Where Di: diameter of dispersed rubber particles.

 ni: the number of rubber particles of diameter Di.

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 a homopolymer and / or a copolymer composed of 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. ) 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.

Reduced viscosity of the above PPE (0.5g / dl, chloroform solution, 30
(Measured in ° C.), A commonly used modified polyphenylene ether resin has a range of 0.50 to 0.70 dl / g,
In order to effectively achieve the object of the present invention, 0.20 ~ 0.50
Those in the range of dl / g are preferable, and those in the range of 0.35 to 0.45 dl / g are more preferable. When the reduced viscosity is in the above range, the thermal deterioration of the butadiene-based polymer in the rubber-modified vinyl aromatic resin during melt mixing of the rubber-modified vinyl aromatic resin and PPE is more effectively suppressed, The finally obtained resin composition has a higher impact strength.

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. A more preferable blending amount is 2 to 10 parts by weight, and a more preferable blending amount is 3
~ 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. You can use the usual mineral oil, but the initial boiling point at 10 mmHg is
A temperature of 210 ° C or higher is more preferable. Examples of mineral oils that satisfy such conditions include Esso Oil Co., Ltd.
Cristol 352, which is a mineral oil produced by the company, can be mentioned. 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 are no particular restrictions on the method of blending the components A to C (or A to C and D), and the 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-Preparation of butadiene-based polymer] The following butadiene-based polymer was prepared according to the method described in JP-A-59-133203.

-G1: polybutadiene rubber-G2: 30% partial hydrogenation of G1-G3: 15% partial hydrogenation of G1-G4: 50% partial hydrogenation of G1 Table 1 shows the microstructures of these butadiene-based polymers. Shown in.

[Reference Example 2-Preparation of rubber-modified vinyl aromatic resin] The butadiene-based polymers G1 to G4 prepared in Reference Example 1 were dissolved in a liquid obtained by mixing styrene and ethylbenzene in a weight ratio of 85:15, and further organic A polymerization stock solution was prepared by adding a peroxide and a chain transfer agent. Each of these polymerization stock solutions was continuously fed to a multi-stage polymerization tank having a stirrer and a devolatilizer directly connected thereto, and polymerized to give a rubber-modified vinyl aromatic resin S1 having a butadiene polymer content of 10%. ~ Got S4.
Table 1 shows the properties of these rubber-modified vinyl aromatic resins.

[Reference Example 3-Adjustment of PPE (P1, P2)] 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, and then an odor was obtained. Cupric chloride 28.4 g, di-n-butylamine 856 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 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 powdered PPE (P1). It was The reduced viscosity was 0.38 dl / g. When obtaining the above PPE (P1), the reduced viscosity was the same except that the catalyst amount and oxygen blowing amount were changed.
0.48 dl / g PPE (P2) was obtained.

[Examples 1 to 5, Comparative Examples 1 to 5] Rubber-modified vinyl aromatic resin, PPE, prepared in Reference Example
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 kneading conditions, physical properties and flammability test are as follows.

・ Kneading conditions: Granulated by TEM-120 twin screw extruder manufactured by Toshiba Machine Co., Ltd. (Cylinder temperature 280 ℃) ・ 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) The results are shown in Table 2.

[Example 6] 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 240 ° 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 6] The same operation as in Example 6 was carried out except that the resin composition of Comparative Example 2 was used instead of the resin composition of Example 1, but the fluidity of the resin was poor and a molded product was obtained. Couldn't get

[Effects of the Invention] As is clear from Table 2, 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 A resin composition containing 10 parts by weight of the rubber-modified vinyl aromatic resin, wherein the rubber-modified vinyl aromatic resin is modified with a partial hydrogenation product of a butadiene-based polymer. .