JPH0625290B2 - Method for producing flame-retardant styrene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a method for producing a flame-retardant styrene resin composition,
An object of the invention is to provide a method for producing a styrene resin composition having excellent heat resistance and impact resistance, good weather resistance and high flame retardancy.

[Conventional technology and problems]

Styrene resins are widely used in various fields such as household appliances and furniture because they are inexpensive and have excellent moldability, mechanical properties, electrical properties, and beautiful appearance.
However, since styrene-based resins are easily flammable, they are subject to many restrictions in use as various regulations regarding flame retardancy such as UL standards are strengthened or obliged.

Therefore, various means for making a styrene resin flame-retardant have been studied, and it has been proposed to add a phosphorus compound, a halogen compound, an inorganic compound such as an antimony oxide as a flame retardant. . Among these, halogen compounds are effective as flame retardants for styrene resins, and among them, tetrabromobisphenol A, decabromodiphenyl ether, and brominated polycarbonates can impart relatively high flame retardancy. Oligomers and the like are known.

However, when tetrabromobisphenol A is used as a flame retardant, the heat resistance and thermal stability of the resin are significantly reduced. JP-A-49-80159 discloses a technique for overcoming such a drawback of tetrabromobisphenol A. However, it cannot be said that heat resistance and thermal stability have been sufficiently solved.

Japanese Patent Publication No. 52-32898 and Japanese Patent Publication No. 56-25953 disclose the use of decabromodiphenyl ether and brominated polycarbonate oligomers as flame retardants to improve the heat resistance and thermal stability of resins. Although proposed, these flame retardants have poor compatibility with polystyrene resins and have problems in terms of dispersibility, mechanical properties of molded articles,
Especially, the reduction of impact resistance is unavoidable. Further, when decabromodiphenyl ether is used as a flame retardant, the weather resistance of the molded product is significantly reduced.

Japanese Patent Publication No. Sho 59-19148 discloses a technique of adding a small amount of a low molecular weight epoxy resin in order to prevent dripping of a decomposition melt during combustion. May reduce the heat resistance of.

[Means for solving problems]

The present inventors have solved these problems, namely,
The present invention has been completed as a result of intensive research conducted for the purpose of obtaining a styrene resin composition having excellent heat resistance and impact resistance, good weather resistance, and high flame retardancy.

That is, the present invention is a styrene resin, a halogen-containing epoxy resin (A) and a halogen-containing aromatic diol (B), melt-kneading in the presence of a catalyst that promotes the reaction of (A) and (B). The present invention relates to a method for producing a flame-retardant styrene resin composition, which is characterized by having a high molecular weight.

The styrene resin in the present invention is a polymer containing an aromatic vinyl compound as a main component. Specific examples include not only styrene monomers and homopolymers of styrene derivative monomers such as α-substituted styrenes such as α-methylstyrene, vinyltoluene, and nucleus-substituted styrenes such as chlorostyrene, but also, for example, styrene-acrylonitrile copolymers. Polymer (AS resin), graft polymer obtained by graft-polymerizing styrene monomer or other monomer on polybutadiene rubber [eg styrene graft polymer (HIPS resin), styrene-acrylonitrile graft polymer (ABS resin)] and these It is a blend of polybutadiene rubber and styrene resin.

The halogen-containing epoxy resin in the present invention is generally represented by the following structural formula.

In the above formula, R is Alternatively, —CH ₂ —, X is bromine or chlorine, i is a natural number of 1 to 4, and m is 0 or a natural number.

Specific examples include halogen-containing bisphenol A and /
Or a reaction product of a halogen-containing bisphenol F and a halogen-containing bisphenol A type epoxy resin and / or a halogen-containing bisphenol F type epoxy resin having a terminal glycidyl ether group, a halogen-containing bisphenol A and / or a halogen-containing bisphenol F And a reaction product obtained by reacting epichlorohydrin with a conventional method.

Specific examples of the halogen-containing bisphenol A and the halogen-containing bisphenol F include tetrabromobisphenol A, dichlorobisphenol A, tetrachlorobisphenol A, dibromobisphenol A, tetrabromobisphenol F and the like. Further, specific examples of the halogen-containing bisphenol A type epoxy resin and the halogen-containing bisphenol F type epoxy resin include tetrabromobisphenol A diglycidyl ether, tetrachlorobisphenol A diglycidyl ether, and dichlorobisphenol A diglycidyl ether. Examples thereof include diglycidyl ether, dibromobisphenol A diglycidyl ether, and tetrabromobisphenol F diglycidyl ether.

Particularly preferred is an epoxy resin obtained by reacting tetrabromobisphenol A with epichlorohydrin,
And an epoxy resin obtained by reacting the epoxy resin with tetrabromobisphenol A.

The halogen-containing aromatic diol in the present invention is an aromatic compound having two phenolic hydroxyl groups in one molecule and containing chlorine or bromine as another substituent.
As specific examples, tetrabromobisphenol A, dichlorobisphenol A, tetrachlorobisphenol A,
There are dibromobisphenol A, a polycarbonate oligomer of tetrabromobisphenol A, tetrabromobisphenol S, tetrabromobisphenol F, and the like.

A particularly preferred halogen containing aromatic diol is tetrabromobisphenol A.

The catalyst in the present invention is generally a compound that accelerates the reaction between the phenolic OH group and the epoxy resin. Specific examples include hydroxides, carbonates, phosphates, silicates, bisphenolates of alkali metals and / or alkaline earth metals, and other specific examples include amine compounds, ammonium compounds, amide compounds, imidazole compounds, Examples include phosphonium salt compounds, phosphonium petaine, phosphoridene, phosphines, sulfonium salts, arsenium salts, selenium salts, tellurium salts, tertiary bismuth compounds, and tertiary antimony compounds.

The method for producing the composition of the present invention is characterized in that a halogen-containing epoxy resin and a halogen-containing aromatic diol are melt-kneaded in a polystyrene resin matrix in the presence of a catalyst to increase the molecular weight. .

The compounding ratio of the halogen-containing epoxy resin and the halogen-containing aromatic diol can be arbitrarily changed, and in order to increase the molecular weight of the flame retardant, it is achieved by bringing the molar ratio of the both closer to 1. Further, if the mole number of the halogen-containing epoxy resin is excessive with respect to the diol,
The epoxy group can be left in the flame retardant, and conversely, if the number of moles of the halogen-containing aromatic diol is excessive,
Terminal OH groups can be left in the flame retardant.

The halogen-containing epoxy resin alone or the halogen-containing aromatic diol alone cannot achieve the desired heat resistance.

The ratio of the number of moles of the halogen-containing epoxy resin to the number of moles of the halogen-containing aromatic diol is preferably 0.1 to 10.

There is no particular limitation on the amount of the high molecular weight catalyst added,
It is preferable to add 0.01 to 5% by weight based on the total amount of the halogen-containing epoxy resin and the halogen-containing aromatic diol.

Melt kneading has fluidity to the extent that a system containing a styrene resin, a halogen-containing epoxy resin and a halogen-containing aromatic diol can be uniformly mixed, and a halogen-containing epoxy resin and a halogen-containing aromatic diol are present as a catalyst. This is achieved by stirring the whole system at a temperature at which the reaction can be performed underneath.

Specific melt kneading methods include a melt extrusion method, a kneader method, a roll method, and various mixers with a heating device. In particular, the melt extrusion method is advantageous in that the blending and pelletizing of the compound can be performed in one step.

There is no particular limitation on the method of premixing the compound, and there are methods using a Banbury mixer, a super mixer, a drum blender, and the like.

It is also possible to add the catalyst before the melt-kneading,
It can also be added during melt kneading.

In the case of kneading by melt extrusion, it is possible to add a catalyst from the vent part.

It is also possible to prepare a master batch in which a halogen-containing epoxy resin, a halogen-containing aromatic diol and a catalyst are mixed in a high concentration with a styrene resin, and mix the master batch with a styrene resin compounding system to perform melt kneading. .

In the production method of the present invention, a halogen-containing epoxy resin,
In addition to halogen-containing aromatic diols, catalysts and styrenic resins, other types of flame retardants or flame retardants used in ordinary thermoplastic resins as required, such as Sb ₂ O ₃ , chlorinated polyethylene, etc. Further, various additives, for example, an ultraviolet selective absorbent, a plasticizer, a coloring agent, a filler, a reinforcing agent, a lubricant, a stabilizer and the like may be added.

〔The invention's effect〕

The flame-retardant styrene resin composition according to the production method of the present invention is 1 /
Even a thin molded plate of 16 inches has a high level of flame retardancy and excellent heat resistance, impact resistance, and weather resistance, so it is extremely useful as a industrial material, mainly as a housing material for electrical equipment.

〔Example〕

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the scope of the present invention is not limited thereto. The evaluation of the molded sample was carried out by the following method.

Flame retardance: UL94 test method (1/16 inch) Dirt impact test: 1.5 inch diameter hemispherical steel used ASTM-1709 heat distortion temperature: ASTM D-648 Izod impact test: ASTM D-256 Vicat Softening point: According to ASTM D-1525 Thermal stability: After 20 minutes of residence in a cylinder (temperature 220 ° C), molding is performed and the appearance is observed.

 ○: No discoloration △: Some yellowing ×: Yellowing Weather resistance: Observe the discoloration of the test piece after 200 hours of the sunshine weatherometer.

○: No discoloration ×: Yellowing Molecular weight (Mw) measurement method: The weight average molecular weight (Mw) was measured by gel bromination chromatography based on a calibration curve using polystyrene as a standard substance. The specific conditions for measurement are shown below.

Column: A-805 (manufactured by Showa Denko KK) 8φ × 500mm HSG-20 (manufactured by Shimadzu Corporation) 8φ × 500mm HSG-15 (〃) 8φ × 500mm HSG-10 (〃) 8φ × 500mm 4 We used a concatenation of books.

Solvent: Tetrahydrofuran Column temperature: 40 ° C. Transfer pressure: 34 Kg / cm ³ Flow rate: 1.2 cc / min Examples 1-5, Comparative Examples 1-5 Impact-resistant polystyrene (Styron QH-40 manufactured by Asahi Kasei Co., Ltd.)
5) 100 parts by weight of halogen-containing epoxy resin, halogen-containing aromatic diol and high-molecular weight catalyst were mixed in the proportions shown in Table 1, mixed in a drum blender, and
A twin-screw extruder equipped with a mmφ vent was used for pelletization at the same time as increasing the molecular weight. Cylinder temperature is 210 ℃, discharge rate is 2
It was 0 to 25 Kg / hr. Then, a test piece was prepared with an injection molding machine (IS-80A manufactured by Toshiba Manufacturing Co., Ltd.). (The cylinder temperature is 220 ° C. and the mold temperature is 60 ° C.) The results of measuring the physical properties of this test piece are shown in Table 1.

Example 6, Comparative Example 6 100 parts by weight of ASB resin (manufactured by Asahi Kasei Corp., Styrac 783) were blended with the respective components in the proportions shown in Table 1, and the test pieces were prepared in the same manner as in Examples 1 to 5 below. Was prepared and the physical properties of the test piece were measured. The results are shown in Table 1.

Claims (1)

[Claims] 1. A styrene-based resin comprising a halogen-containing epoxy resin (A) and a halogen-containing aromatic diol (B), (A)
A method for producing a flame-retardant styrene-based resin composition, which comprises increasing the molecular weight by melt-kneading in the presence of a catalyst that accelerates the reaction between the (B) and