JPH0586254A - Flame-retardant styrenic resin composition having thermal shock resistance - Google Patents

Abstract

PURPOSE:To obtain the, subject composition useful for parts of household electric appliances, parts of office automation devices, etc., comprising a rubber- modified styrenic resin, a polyphenylene ether, ammonium sulfate, a phosphorus- containing flame-retardant, etc., containing halogen compound. CONSTITUTION:The objective composition comprises (A) 100 pts.wt. total amounts of (i) a rubber-modified styrenic resin and (ii) 10-30 pts.wt. polyphenylene ether, (B) 1-30 pts.wt. ammonium sulfate, (C) 1-30 pts.wt. phosphorus-containing flame-retardant and (D) 5-30 pts.wt. triazine skeleton- containing compound such as melamine.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a resin composition having excellent flame retardancy. More specifically, it relates to a flame-retardant, heat-resistant and impact-resistant styrene resin composition containing no halogen compound.

[0002]

2. Description of the Related Art Rubber-modified vinyl aromatic resins typified by HIPS are excellent in moldability and dimensional stability, as well as in impact resistance, rigidity, and electrical insulation, and are therefore home appliances and OA. It has come to be used in various fields including equipment parts.

In recent years, the demand for flame retardancy has been increasing for plastic materials used in such fields due to safety concerns, and various flame retardancy standards have been established. Various methods have been devised as a method for imparting flame retardancy to a resin that is easily flammable, but generally, halogen compounds such as bromine compounds having a high flame retardant effect, and antimony oxide if necessary. Is added to the resin. Known bromine compounds include nuclear bromine-substituted aromatic compounds such as decabromodiphenyl ether, tetrabromobisphenol A, and brominated phthalimide.
Although the method by adding these flame retardants can obtain excellent flame retardancy, impact strength and heat distortion temperature decrease, and in some cases the flame retardant bleeds out on the surface of the resin molded product to improve the appearance of the molded product. It had problems such as making it worse. Further, during the molding of the resin, there are problems such that the halogen compound is thermally decomposed to generate a gas harmful to the human body and the mold and the screw are corroded.

For this reason, methods for flame retardation 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 above hydrated metal compound is added. However, there is a drawback that the original characteristics of the resin are lost.

On the other hand, as a method not using such a hydrated metal compound, a flame-retardant resin composition comprising a nitrogen-containing compound selected from vinyl aromatic resin, polyphenylene ether, organic phosphorus compound, triazine and / or its derivative. (JP-A-54-38348, JP-A-54-38349, European Patent No. 311,909), a flame-retardant resin composition comprising polyphenylene ether, a styrene resin and red phosphorus (US Patent No. 4,461,874), a flame-retardant resin composition prepared by mixing red phosphorus, melamine, and a heat-crosslinking curable resin with an ABS resin (JP-A-61-291643) is proposed. However, the resin compositions described in JP-A-54-38348, JP-A-54-38349, European Patent No. 311,909, US Pat. No. 4,461,874 and JP-A-61-291643. All of them are useful flame-retardant resin materials that do not use a halogen compound, but since polyphenylene ether having low fluidity is the main component, there is a problem that the moldability of the resin composition is poor.

Furthermore, JP-A-63-202639 discloses a flame-retardant resin composition comprising a polyolefin-based or polystyrene-based resin, ammonium sulfate and aluminum hydroxide. However, the composition of the publication has a problem that the impact resistance is poor because it uses a large amount of ammonium sulfate and aluminum hydroxide.

Therefore, the present inventors previously combined (a) rubber-modified styrene resin, (b) polyphenylene ether, (c) ammonium sulfate, (d) organic phosphorus compound, and (v) triazine skeleton-containing compound. It was found that the flame-retardant property is improved by maintaining the impact resistance by doing so and applied for a patent (Japanese Patent Application No. 3-213793).

However, since the resin composition of the publication uses only the organic phosphorus compound as the phosphorus-containing flame retardant,
In order to impart a high degree of flame retardancy, it is necessary to use a large amount of an organic phosphorus compound, and as a result, there arises a problem that heat resistance and impact resistance decrease.

[0009]

SUMMARY OF THE INVENTION In view of the above situation, the present invention does not have the above-mentioned problems, that is, the conventional flame retardants can be greatly reduced, and the high flame retardancy and impact resistance are high. An object of the present invention is to provide a styrene resin composition having properties.

[0010]

Means for Solving the Problems As a result of intensive studies on the improvement of the flame retardancy of styrene resins, the present inventors have found that (A) a rubber-modified styrene resin and (B) a polyphenylene ether
By combining (D) a phosphorus-containing flame retardant and (E) a compound containing a triazine skeleton, (C) ammonium sulfate,
Surprisingly, it was found that even if the conventional flame retardant was drastically reduced, it was possible to dramatically improve the flame retardancy while maintaining the heat resistance and impact resistance, and arrived at the present invention. ..

That is, the present invention provides (A) a rubber-modified styrene resin, (B) polyphenylene ether, (C) ammonium sulfate, (D) a phosphorus-containing flame retardant comprising red phosphorus and an organic phosphorus compound, and (E) triazine. Flame-retardant heat and impact resistant styrenic resin composition comprising a skeleton-containing compound, in particular, (A) the rubber-modified styrenic resin and (B) polyphenylene ether account for 10 to 10 parts by weight of the component (B) in total 100 parts by weight. With respect to 100 parts by weight of the resin component which is 30 parts by weight, (C) ammonium sulfate is 1 to 30 parts by weight, (D) phosphorus-containing flame retardant is 1 to 30 parts by weight, and (E) triazine skeleton-containing compound is 5 to A flame-retardant, heat-resistant and impact-resistant styrene-based resin composition of 30 parts by weight is provided.

The present invention will be described in detail below.

The resin composition of the present invention comprises (A) rubber-modified styrene resin, (B) polyphenylene ether, (C) ammonium sulfate, (D) phosphorus-containing flame retardant, and (E) triazine skeleton-containing compound, The object of the invention cannot be achieved without any of them.

The above-mentioned component (A) constitutes the main component of the molding resin composition and plays a role of maintaining the strength of the molded product. The above-mentioned component (D) is flame retardant to the component (A) together with the component (E). The components (B) and (C) are components for further increasing the flame retardancy imparting effect of the components (D) and (E).

Here, the ammonium sulfate (C) acts as a dehydrating agent, and promotes carbonization of the composition by the combination of the sulfuric acid produced upon combustion and the polyphenylene ether (B).

The rubber-modified styrenic 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. A known bulk polymerization, bulk suspension polymerization, solution polymerization, or emulsion polymerization of a monomer mixture by adding an aromatic vinyl monomer in the presence thereof and a vinyl monomer copolymerizable therewith, if necessary. Is obtained by

Examples of such resins include high impact polystyrene, ABS resin (acrylonitrile-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), AES resin (acrylonitrile-ethylene). Propylene rubber-styrene copolymer) and the like.

Here, the rubbery polymer needs to have a glass transition temperature (Tg) of -30 ° C. or lower,
If it exceeds 30 ° C, the impact resistance will decrease.

Examples of such a rubber-like polymer include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene), and saturated rubber obtained by hydrogenating the above diene rubber, isoprene rubber and chloroprene rubber. Acrylic rubbers such as polybutyl acrylate, ethylene-propylene-diene monomer terpolymer (EPDM) and the like can be mentioned, and diene rubbers are particularly preferable.

The aromatic vinyl monomer which is an essential component in the graft-polymerizable monomer mixture is, for example, styrene or α.
-Methylstyrene, paramethylstyrene, p-chlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, etc., with styrene being the most preferable, but mainly other styrene aromatic vinyl monomers. May be copolymerized.

If desired, one or more monomer components copolymerizable with the aromatic vinyl monomer may be introduced as a component of the rubber-modified styrene resin. When it is necessary to enhance oil resistance, unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile can be used.

When it is necessary to reduce the melt viscosity during blending, an acrylate ester composed of an alkyl group having 1 to 8 carbon atoms can be used. Furthermore, when it is necessary to further increase the heat resistance of the polymer composition, acrylic acid, methacrylic acid, maleic anhydride, N-
A monomer such as a substituted maleimide may be copolymerized. The content of the vinyl monomer copolymerizable with the vinyl aromatic monomer in the monomer mixture is 0 to 40% by weight.

The rubber-like polymer in the rubber-modified styrene resin of the present invention is preferably 5 to 80% by weight, more preferably 10 to 50% by weight, and the graft-polymerizable monomer mixture is preferably 95 to 20% by weight. %, More preferably 90 to 50% by weight. Outside this range, the impact resistance and rigidity of the desired polymer composition cannot be balanced. Furthermore, the rubber particle size of the styrene polymer is 0.1 to 5.0 μm.
Is preferable, and 0.2 to 3.0 μm is particularly preferable. Outside the above range, the impact resistance tends to decrease.

The component (B) of the present invention, polyphenylene ether (hereinafter abbreviated as PPE), is a homopolymer and / or a copolymer having a bonding unit represented by the following formula.

[0025]

[Chemical 1]

(Here, R ₁ , R ₂ , R ₃ , and R ₄ are each selected from the group consisting of hydrogen, hydrocarbon, and substituted hydrocarbon groups, and may be the same or different from each other. .) As a concrete example of this PPE, 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 preferred. The method for producing such PPE is not particularly limited as long as it is obtained by a known method, and for example, a complex of a cuprous salt and an amine by the method described in US Pat. No. 3,306,874 is used as a catalyst, For example, it can be easily produced by oxidative polymerization of 2,6 xylenol.Other than that, U.S. Pat.No. 3,306,875, U.S. Pat.No. 3,257,357, U.S. Pat.No. 3,257,358, and Japanese Patent Publication No. 52-178.
It can be easily produced by the methods described in JP-A No. 80 and JP-A No. 50-51197. The reduced viscosity of the PPE used in the present invention (0.5 g / dl, chlorofilm solution, measured at 30 ° C.) is 0.
It is preferably in the range of 20 to 0.70 dl / g, 0.30 to 0.60
More preferably, it is in the range of dl / g. Examples of means for satisfying the above requirements regarding the reduced viscosity of PPE include adjustment of the amount of catalyst during the production of PPE.

The component (C) of the present invention, ammonium sulfate, is an ordinary granular inorganic compound for fertilizers, which is a higher fatty acid, polysiloxane or the like in order to improve water resistance and compatibility with a styrene resin. It may be surface-treated.

Further, the phosphorus-containing flame retardant of the component (D) of the present invention is a flame retardant composed of red phosphorus and an organic phosphorus compound. By using both in combination, flame retardancy, heat resistance and impact resistance are obtained. You can balance your sex.

As a specific example of the above-mentioned red phosphorus, in addition to general red phosphorus, the surface thereof is previously formed with a film of a metal hydroxide selected from aluminum hydroxide, magnesium hydroxide, zinc hydroxide and titanium hydroxide. Those that have been covered,
Aluminum hydroxide, magnesium hydroxide, zinc hydroxide, water coated with a metal hydroxide selected from aluminum hydroxide, magnesium hydroxide, zinc hydroxide, titanium hydroxide and a thermosetting resin. It is also possible to suitably use a metal hydroxide selected from titanium oxide, which is doubly coated with a film of thermosetting resin.

Examples of the organic phosphorus compound as the component (D) include phosphine, phosphine oxide, biphosphine, phosphonium salt, phosphinate, phosphoric acid ester, and phosphorous acid ester. More specifically, methyl neopentyl phosphite, pentaerythritol diethyl diphosphite, methyl neopentyl phosphonate, phenyl neopentyl phosphate, pentaerythritol diphenyl diphosphate, dicyclopentyl hypophosphite, dineopentyl hypophosphite. Examples thereof include phyto, phenylpyrocatechol phosphite, ethylpyrocatechol phosphate, dipyrocatechol hypophosphite and the like.

The triazine skeleton-containing compound of the component (E) of the present invention acts as a flame retardant aid for phosphorus-containing compounds, and specific examples thereof include melamine, succinoguanamine, adipoguanamine and methylglutaro. Although guanamine etc. can be mentioned, melamine is the most preferable.

In the resin composition of the present invention, (A) rubber-modified styrenic resin and (B) polyphenylene ether form a resin component, and the proportion of component (B) in 100 parts by weight of the resin component is , 10 to 30 parts by weight is preferable. When the amount of the component (B) is less than 10 parts by weight, the amount of carbonization residue is small and the flame retardancy is insufficient, and when it exceeds 30 parts by weight, the fluidity is deteriorated, which is not preferable. The more preferable range of the component (B) is 10 to 2.
5 parts by weight.

Next, in the resin composition of the present invention, 1 part of (C) ammonium sulfate is added to 100 parts by weight of the total of the components (A) and (B).
~ 30 parts by weight, 1 to 30 parts by weight of (D) phosphorus-containing flame retardant, and (E)
The triazine skeleton-containing compound is preferably in the range of 5 to 30 parts by weight. If it deviates from the above range, the flame retardancy or impact resistance is lowered, which is not preferable.

The resin composition of the present invention is obtained by, for example, melt-kneading each of the above-mentioned polymers with a commercially available single-screw extruder, a twin-screw extruder or the like. At that time, an antioxidant such as BHT is used. A UV absorber, a tin-based heat stabilizer, a lubricant such as stearic acid and zinc stearate, a filler, a reinforcing material, a dye, a pigment and the like can be added if necessary.

By subjecting the composition of the present invention thus obtained to, for example, injection molding or extrusion molding, a molded article having excellent flame retardancy and impact resistance can be obtained.

[0036]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

The measurements in Examples and Comparative Examples were carried out using the following methods or measuring instruments.

(1) Flame retardance It was evaluated by the VB (Vertical Burning) method based on UL-94. (1/8 "test piece) (2) Izod impact strength Measured at 23 ° C according to the method according to ASTM-D256. (V notch, 1/8" test piece) (3) Vicat softening temperature According to ASTM-D1525 It was measured by the method described above and used as a measure of heat resistance.

Example 1 (a) Production of rubber-modified styrene resin (HIPS) A polymerization stock solution having the following composition was prepared.

Polybutadiene rubber 8.0 parts by weight (NF-35A manufactured by Asahi Chemical Industry Co., Ltd.) Styrene 77.0 parts by weight Ethylbenzene 15.0 parts by weight α-Methylstyrene dimer 0.06 parts by weight Stearyl 3- (3,5-di-shaributyl 0.10 parts by weight- 4-Hydroxyphenyl) -propionate Then, the above stock solution for polymerization was continuously fed to a multistage reactor equipped with a stir bar to carry out polymerization. The polymerization temperature and the stirring number were adjusted so that the weight average particle diameter of the rubber particles was 2.3 μm and the solid content concentration in the final reactor was 80% by weight. Subsequently, it was introduced into a devolatilization device for the polymerization liquid to obtain a rubber-modified vinyl aromatic resin (HIPS) having a rubber content of 10% by weight. As a result of analyzing the obtained rubber-modified vinyl aromatic resin, the gel content was 32% by weight, the swelling index of the gel component was 12.5, and the reduced viscosity of the matrix portion was 0.75 dl / g.

(B) Production of polyphenylene ether (PPE) A reactor made of stainless steel having an oxygen blowing port at the bottom of the reactor and having a cooling coil and stirring blades inside was thoroughly replaced with nitrogen, and then brominated. 2,6 in a mixed solvent of 54.8 g of cupric acid, 1110 g of di-n-butylamine, 20 liters of toluene, 16 liters of n-butanol, and 4 liters of methanol.
-Xylenol 8.75Kg was melted and charged into the reactor. Continue to blow oxygen into the reactor while stirring to keep the internal temperature at 30
Polymerization was carried out for 180 minutes while controlling at ℃. After completion of 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 then dried to obtain a powdery PPE. The reduced viscosity was 0.55 dl / g.

(C) Ammonium Sulfate Commercially available ammonium sulfate (special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.) was used (referred to as (NH ₄ ) ₂ SO ₄ ).

(D) Phosphorus-containing flame retardant As red phosphorus, commercially available red phosphorus powder ((Rin Kagaku Kogyo Co., Ltd.)
Made, trade name Nova Excel 150) (referred to as RP)),
Commercially available triphenyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd. (referred to as TPP)) was used as the organic phosphorus compound.

(E) Triazine skeleton-containing compound As the triazine skeleton-containing compound, commercially available melamine (manufactured by Wako Pure Chemical Industries, Ltd.) was used (referred to as ML).

(F) Preparation and Evaluation of Composition HIPS / PPE / (NH ₄ ) ₂ SO ₄ / RP / TPP / ML in a weight ratio of 81/19/8
Mechanically mix at a ratio of /0.7/8/6 and use a Labo Plastomill manufactured by Toyo Seiki Seisakusho at a melting temperature of 230 ° C and a rotation speed of 50 rpm.
Melted for 5 minutes. A 1/8 "thick test piece was prepared from the polymer composition thus obtained by hot pressing and evaluated for flame retardancy, Vicat softening temperature, and Izod impact strength. The results are shown.

Comparative Example 1 The same experiment as in Example 1 was repeated except that (NH ₄ ) ₂ SO ₄ was not added in Example 1. The results are shown in Table 1.

Comparative Example 2 The same experiment as in Example 1 was repeated except that the phosphorus-containing flame retardant (RP and TPP) was not added in Example 1. The results are shown in Table 1.

Comparative Example 3 The same experiment as in Example 1 was repeated except that ML was not added in Example 1. The results are shown in Table 1.

Comparative Example 4 The same experiment as in Example 1 was repeated except that the HIPS / PPE resin component 100 having a weight ratio of 81/19 in Example 1 was changed to HIPS100. The results are shown in Table 1.

COMPARATIVE EXAMPLE 5 In Example 1, the composition was replaced with HIPS / PPE / without RP.
(NH ₄ ) ₂ SO ₄ / TPP / ML in weight ratio 77/23/8/12/12
The same experiment as in Example 1 was repeated, except that The results are shown in Table 1.

[0051]

[Table 1]

[0052]

The composition of the present invention is a styrenic resin composition having high flame retardancy, heat resistance and impact resistance even if the conventional flame retardant is largely reduced. This composition is suitable for home electric appliance parts, office automation equipment parts and the like, and plays a large role in the industrial world.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 55/02 LMF 7142-4J 71/12 LQN 9167-4J LQP 9167-4J

Claims (1)

[Claims] 1. From (A) a rubber-modified styrene resin, (B) polyphenylene ether, (C) ammonium sulfate, (D) a phosphorus-containing flame retardant comprising red phosphorus and an organic phosphorus compound, and (E) a triazine skeleton-containing compound. A flame-retardant, heat-resistant and impact-resistant styrene resin composition.