JPS6347753B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a flame-retardant resin composition, and more specifically, the present invention relates to a flame-retardant resin composition, and more specifically, a thermoplastic resin such as a styrene resin, and a conventional flame retardant.
The present invention relates to a resin composition that exhibits a high degree of flame retardancy while maintaining the excellent physical properties of a thermoplastic resin by blending a specific additive with a xylene resin. In general, thermoplastic resins such as styrene resins are easily flammable, so their fields of use are restricted from the viewpoint of safety. Therefore, in order to improve the flame retardancy of these resins, flame retardants such as organic halogen compounds and phosphoric acid ester compounds, and further flame retardant aids such as antimony trioxide are added. Incidentally, in recent years, flame retardant standards such as UL standards have been strengthened year by year, so it has become necessary to add a large amount of flame retardant in order to obtain a resin that exhibits excellent flame retardancy. However, when the amount of flame retardant added increases, it not only causes a decrease in the physical properties of the resin composition, but also discoloration of the resin due to thermal decomposition of the flame retardant during melt molding, generation of toxic corrosive gas, and weather resistance of the resulting resin molded product. Problems may arise, such as a decrease in performance, the generation of toxic gas during combustion, or the toxicity of the flame retardant itself. In order to solve the above-mentioned problems of the prior art, the present inventors developed a flame-retardant resin composition containing xylene resin and mesitylene resin, and have already filed an application for this composition (Japanese Patent Application No. 86076, Showa era
Patent application (1) filed on December 25, 1954). In order to develop a resin composition with superior flame retardancy, the present inventors have conducted further intensive research and found that in addition to conventionally used flame retardants such as organic halogen compounds and xylene-based resins, sulfur The present inventors have discovered that the desired resin composition can be obtained by blending a thermoplastic resin with a specific antioxidant, and have completed the present invention. That is, the present invention provides a flame-retardant resin composition comprising (A) a thermoplastic resin, (B) an organic halogen compound, (C) a xylene resin, and (D) sulfur and/or a sulfur-containing antioxidant. This is what we provide. The thermoplastic resin, component (A) of the present invention, is a base component of the composition of the present invention. Examples of this thermoplastic resin include styrene-based resins such as polystyrene, rubber-modified polystyrene (HI polystyrene), styrene-butadiene copolymer, styrene-acrylonitrile copolymer (AS resin), and styrene-butadiene-acrylonitrile copolymer (ABS resin). Examples include resins or polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, and further examples include polyamide resins, polycarbonate resins, polyester resins, vinyl chloride resins, and methyl methacrylate resins. Especially styrene resin,
In particular, styrenic resin containing rubber is most preferably used. Next, the organic halogen compound, which is component (B) of the present invention, acts as a flame retardant, and is suitable for aromatic compounds, alicyclic compounds, and alicyclic compounds containing halogen atoms such as bromine, chlorine, and fluorine in their molecular structure. It includes all organic halogen compounds that have a flame retardant effect, such as group compounds. Specifically, hexabromobenzene; pentabromotoluene; biphenyl bromide; triphenyl chloride; diphenyl bromide ether; tetrachlorophthalic acid; tetrabromophthalic anhydride; tribromophenol; tribromophenyl; dibromo alkyl ether; Bromobisphenol S; Tetrachlorobisphenol A; Aromatic halogen compounds such as 2,2-bis(4-hydroxy-3,5-dibromophenyl)-propane (hereinafter referred to as "tetrabromobisphenol A") Or alicyclic halogen compounds such as monochloropentabromocyclohexane; hexabromocyclododecane; perchloropentacyclodecane; hexachloroendomethylenetetrahydrophthalic anhydride; and further chlorinated paraffin;
Examples include aliphatic halogen compounds such as chlorinated polyethylene; tetrabromoethane; tetrabromobutane; tris (β-chloroethyl) phosphate; tris (dichloropropyl) phosphate; tris (dibromopropyl) phosphate; tris (chlorobromopropyl) phosphate; be able to. The blending ratio of the above organic halogen compound, which is component (B) of the present invention, varies depending on the types of other components, amounts added, and other conditions, and cannot be unambiguously determined. The amount should be 2 to 30 parts by weight, preferably 4 to 20 parts by weight, based on 100 parts by weight of plastic resin. If it is less than 2 parts by weight, the resulting composition will have insufficient flame retardancy, while if it exceeds 30 parts by weight, the physical properties of the composition will deteriorate, toxic gas will be generated during melt molding and combustion, and corrosivity will increase, etc. This will cause some inconvenience. Next, the xylene resin, which is the component (C) of the present invention, exhibits the effect of imparting flame retardancy to the composition obtained together with the organic halogen compound, which is the component (B), and is particularly effective against melting during combustion. Effectively works to prevent dripping. Various types of xylene resins can be considered, such as xylene-formaldehyde resin or mesitylene-formaldehyde resin obtained by condensing xylene or mesitylene with formaldehyde in the presence of a strong acid catalyst. Further, examples thereof include modified xylene resins obtained by modifying these xylene resins with phenol or alkylphenol, as well as modified xylene resins obtained by modifying these xylene resins with organic acids, alcohols, amines, and the like. Furthermore, these xylene resins may be in any of liquid, starch syrup, powder, and block forms, and there are no particular restrictions on their molecular weight. However, in consideration of the physical properties of the composition such as heat resistance, it is preferable to use a composition having a relatively high melting point, such as a powder or block. Here, even if a novolac resin, melamine resin, phenoxy resin, etc. are used instead of the xylene resin, almost no improvement in flame retardancy is observed. The blending ratio of the xylene resin, which is the component (C) above, may be selected as appropriate depending on various conditions, but it is usually 0.2 to 30 parts by weight, based on 100 parts by weight of the thermoplastic resin, which is the component (A). Preferably it should be between 0.5 and 15 parts by weight. If it is less than 0.2 parts by weight, the effect of addition will not be sufficiently obtained, and if it exceeds 30 parts by weight, there is a risk that the physical properties of the composition will be deteriorated, which is economically undesirable. Next, the sulfur and/or sulfur-containing antioxidant, which is the component (D) of the present invention, together with the organic halogen compound, which is the component (B), and the xylene resin, which is the component (C), imparts flame retardancy to the resulting composition. It shows the effect of imparting. Although the details of the mechanism by which component (D) contributes to improving flame retardancy are not clear, it is thought that some kind of chemical reaction occurs when the composition is burned. These sulfur and sulfur-containing antioxidants can be used alone or in combination.
Examples of the sulfur-containing antioxidant include those generally known as rubber vulcanization accelerators. For example, zinc N-ethyl-N-phenyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate,
Dithiocarbamates such as zinc dibutyl dithiocarbamate, xanthogen salts such as sodium isopropyl xanthogenate, zinc isopropyl xanthogenate, nickel isopropyl xanthogenate, tetramethylthiuram monosulfide, tetraethylthiuram disulfide, dimethyl diphenyl Thiurams such as thiuram disulfide, 2
- Thiazoles such as mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole, dibenzothiazole disulfide, benzimidazoles such as 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, and 2-mercaptomethylbenzimidazole etc. can be given. Among these antioxidants, it is preferable to use those with low volatility. Here, instead of sulfur-containing antioxidants, trinonylphenyl phosphite (TNP), tricresyl phosphate (TCP), and 2,6-di-t, which are often used as antioxidants in thermoplastic resins, are used.
Even if -butyl-p-cresol or the like is used, almost no improvement in the flame retardant effect is observed. The blending ratio of sulfur and sulfur-containing antioxidant, which is component (D) above, may be selected as appropriate depending on various conditions, but it is usually 0.1 to 100 parts by weight of the thermoplastic resin, which is component (A). It should be 15 parts by weight, preferably 0.2 to 8 parts by weight. If the amount is less than 0.1 part by weight, the effect of addition will not be sufficiently obtained, and if it exceeds 15 parts by weight, the physical properties of the composition may be deteriorated, which is not economically preferable. In the present invention, in addition to the above components (A), (B), (C), and (D), flame retardant aids, reinforcing agents, fillers, heat stabilizers, ultraviolet absorbers, plasticizers, and lubricants may be used as necessary. , a coloring agent, etc. can be added as appropriate. Here, antimony trioxide is mainly used as the flame retardant aid, and zirconium dioxide, molybdenum oxide, aluminum hydroxide, zinc borate, barium metaborate, etc. can also be used. The blending ratio of this flame retardant aid is not particularly limited, but it is usually 1 to 10 parts by weight, preferably 2 to 6 parts by weight, per 100 parts by weight of the thermoplastic resin (A). In addition, various reinforcing agents and fillers can be used depending on the purpose of the resulting composition, such as rubbers, organic fibers or glass fibers, inorganic fibers such as carbon fibers, calcium carbonate,
Examples include talc, clay, and aluminum hydroxide. In producing the composition of the present invention, the above-mentioned components (A), (B), (C), and (D), as well as various additives as necessary, are mixed in predetermined proportions, and then rolled milled,
Thoroughly knead using a Banbury mixer, kneader, Henschel mixer, single screw extruder, twin screw extruder, etc. Since the composition of the present invention thus obtained contains a xylene resin and specific additives, it can exhibit a sufficient flame retardant effect with a smaller amount of organic halogen compound than conventional thermoplastic resins. can. Therefore, the halogen content in the composition is reduced, and as a result, various troubles caused by halogens, such as a decrease in physical properties such as weather resistance and mechanical strength, and the generation of toxic gas, are effectively prevented. Furthermore, since the drip resistance of the composition is improved, melt dripping during combustion is hardly observed. Therefore, the resin composition of the present invention can be effectively used as a material for electrical products, mechanical parts, automobiles, building materials, ornaments, and various other products. Next, examples of the present invention will be shown. Examples 1 to 5 and Comparative Examples 1 to 4 Tetrabromobisphenol A (TBA),
Antimony trioxide, xylene resin, and additives were blended in predetermined proportions, melted and kneaded using a Banbury mixer, and then pelletized using a sheet pelletizer. By injection molding from this pellet, 3
A test piece of mm x 6.5 mm x 127 mm was prepared and ASTM
Oxygen index (OI) was measured according to D2863-70.
The results are shown in Table 1. Examples 6 to 7 and Comparative Examples 5 to 10 In the above Example 1, as the thermoplastic resin
A test piece was prepared using 100 parts by weight of ABS resin (trade name: ABS resin JSR-35, manufactured by Japan Synthetic Rubber Co., Ltd.) and using mesitylene resin instead of xylene resin. , the oxygen index (OI) was measured. The results are shown in Table 2. Examples 8 to 14 and Comparative Examples 8 to 14 Tetrabromo bisphenol A (TBA),
Antimony trioxide, xylene resin, mesitylene resin, and additives were blended in predetermined proportions, melted and kneaded using a Banbury mixer, and then pelletized using a sheet pelletizer. A flammability test piece (1/8 inch thick) was molded from this pellet by injection molding, and a UL-94 standard vertical flammability test was conducted.
The results are shown in Table 3.

[Table] Manufactured by Co., Ltd.

【table】

【table】

【table】

【table】

Claims (1)

[Claims] 1 (A) thermoplastic resin, (B) organic halogen compound, (C)
A flame-retardant resin composition containing a xylene resin and (D) sulfur and/or a sulfur-containing antioxidant. 2 (A) 100 parts by weight of thermoplastic resin, (B) 2 to 30 parts by weight of organic halogen compound, (C) 0.2 to 30 parts by weight of xylene resin
The composition according to claim 1, which contains 0.1 to 15 parts by weight and (D) sulfur and/or sulfur-containing antioxidant.