JPS62288646A - Resin composition having excellent flame-retardance - Google Patents

Abstract

PURPOSE:To obtain the titled composition having high cracking resistance and excellent heat-resistance and toughness and injection-moldable with little gas generation, by compounding a polyphenylene ether resin and a styrene resin with a flame-retardant consisting of a specific phosphorus compound. CONSTITUTION:The objective composition can be produced by compounding (A) 10-90pts.wt. of a polyphenylene ether resin, preferably poly(2,6-dimethyl-1,4- phenylene) ether or a copolymer obtained by grafting styrene thereto, (B) 80-20pts. of a styrene resin, preferably a rubber-reinforced polystyrene and (C) 1-25pts. of a flame retardant consisting of a monofunctional phenol (prefer ably phenol) and the compound of formula II produced by the reaction of a polyfunctional phenol of formula I (R is H or 1-8C alkyl; n is integer of >=2; Ar is phenyl, alkyl-substituted phenyl or halophenyl) with a halogenated phospho rus compound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flammable resin composition comprising a polyphenylene ether resin and a styrene resin.

[Conventional technology]

Conventionally, resin compositions consisting of polyphenylene ether resin and styrene resin have been found to have good moldability, processability, heat resistance,
Due to its properties such as impact resistance, flame retardance, and electrical properties, it is widely used in industrial parts, electrical parts, office equipment housings, automobile parts, precision parts, etc., and its usage has increased significantly in recent years. ing. With such an increase in usage, there is a strong desire to improve some of the resin properties.

Conventionally, triphenyl phosphate has been used to impart flame retardancy to resin compositions made of polyphenylene ether resin and styrene resin, but it generates gas during injection molding and adheres to the inside of the mold. However, problems such as molding troubles and deterioration of the appearance of the molded product occur. Furthermore, the use of triphenyl phosphate has the drawback of significantly impairing heat resistance.

[Problem that the invention seeks to solve]

As a flame retardant in resin compositions consisting of polyphenylene ether resin and styrene resin, Japanese Patent Publication No. 53-418
and U.S. Pat. No. 4,526,917, phosphoric triesters derived from monofunctional, low molecular weight phenolic compounds, such as triphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, dimethyl When dithylphenyl phosphate, trimeditylphenyl phosphate, etc. are used, their vapor pressure is high, so they gasify during injection molding and adhere to the inside of the mold and gas vents, causing problems during molding and poor appearance of molded products. etc., and also caused a decrease in heat resistance. On the other hand, as seen in JP-A-55-118957, when a flame retardant derived from a polyfunctional phenol such as bisphenol A is used, the decrease in heat resistance is reduced compared to when triphenyl phosphate or the like is used. Although gas generation during injection molding is reduced, crank resistance and impact strength are reduced, reducing its utility as an engineering plastic.

[Means for solving problems]

As a result of intensive studies on flame retardants used in compositions consisting of polyphenylene ether resin compositions and styrene resins, the above-mentioned problems have been solved at once by the present invention described below.

That is, the present invention relates to a resin composition having good flame retardancy, which is a composition comprising a polyphenylene ether resin, a styrene resin, and a flame retardant, wherein the flame retardant is a phosphorus compound represented by the following general formula. [R is hydrogen or carbon number 1-8
n is a positive integer of 2 or more, Ar is a phenyl group, an alkyl-substituted phenyl group, or a halophenyl group. ] The present invention will be explained below.

Regarding the phosphorus compound used in the present invention, in polyphosphate obtained from a combination of monofunctional phenol and polyfunctional phenol, the higher the proportion of monofunctional phenol, the more advantageous it is in terms of toughness and cost. Bisphenol A obtained
In polyphosphates, phenol and bisphenol A
The molar ratio approaches 1, which is disadvantageous. In addition, phosphorus atoms are incorporated into the main chain skeleton, which causes disadvantages in terms of physical properties. In this respect, the phosphorus compound used in the present invention has a large molar ratio of monofunctional phenol, which is advantageous in terms of cost, and it also has excellent toughness and oil resistance. The quality is also excellent.

The polyphenylene ether resin referred to in the present invention generally refers to a homopolymer whose structural unit consists of the following (1) or a copolymer consisting of the following (1) and (II).

[Here, R9, R2, R3, R9, circles are the same or different alkyl groups having 1 to 4 carbon atoms excluding tert-butyl groups, aryl groups, hydroxyalkyl groups, /%roalkyl groups, halogens, hydrogen are monovalent residues such as R5,
A circle is not hydrogen at the same time. ] The amount of (1) is 90 to 10
0% by weight, and the amount of (II) is 0-10% by weight. If the amount of (n) exceeds 10% by weight, the heat resistance will increase, but the processability will be poor, which is unsuitable.

Typical examples of homopolymers of polyphenylene ether include poly (2,6-dimethyl-1,4-)unisine) ether, poly (2-methyl-6-ethyl-1,4-phenylene) ether, and poly(2-methyl-6-ethyl-1,4-phenylene) ether. 2,6-diethyl-1,
4-phenylene)ether, poly(2-ethyl-6-
n-propyl-1,4-phenylene) ether, poly(
2,6-di-n-propyl-1,4-phenylene) ether, poly (2-methyl-6-n-phthyl-1,4-phenylene) ether, poly (2-ethyl-6-isopropyl-1,4- phenylene) ether, poly(2-
methyl-6-chloro-1,4-phenylene) ether,
Poly(2-methyl-6-hydroxyethyl-1,4-
) unicine) ether, poly(2-methyl-6-chloroethyl-1,4-phenylene) ether, and other homopolymers.

The polyphenylene ether copolymer is preferably a polyphenylene ether copolymer mainly composed of a polyphenylene ether structure obtained by copolymerizing monovalent phenols each represented by the following general formula.

[Here, R5, R2, Ro, ~, Hiki, Kame are the same or different alkyl groups having 1 to 4 carbon atoms excluding tert-butyl groups, aryl groups, hydroxyalkyl groups, haloalkyl groups, halogens, hydrogen, etc. There are monovalent residues, and R3 is not hydrogen at the same time. ] As such copolymers,
For example, 2.6-dimethylphenol and 2.3-dimethyl6-ethylphenol, 2-methyl6-ethylphenol and 2.3-dimethyl6-ethylphenol, 2.6-dimethylphenol and 2.3-dimethyl6-ethylphenol;
-dinitylphenol and 2,3-dimethyl6-ethylphenol, 2.6-dimethylphenol and 2.3.6-
) Limethylphenol, 2-methyl-6-ethylphenol and 2.3.6-) Limethylphenol, 2.6-
dinitylphenol and 2.3.6-)limethylphenol, 2-methyl-6-chloromethylphenol and 2.
3.6-drimethylphenol is mentioned.

The most preferred among them is poly(2,6-dimethyl-1,4-phenylene)ether.

Furthermore, the present composition includes the use of a polyphenylene ether obtained by graft copolymerizing styrene and/or a monomer copolymerizable with styrene.

Examples of monomers copolymerizable with styrene include α-
Methylstyrene, methylstyrene, dimethylstyrene,
Vinyltoluene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, and esters of methacrylic acid are used.

The means for grafting these monomers onto polyphenylene ether is not particularly limited, but for example,
-30991, Japanese Patent Publication No. 52-38596, and Japanese Patent Application Laid-Open No. 52-142799, etc., in which styrene and/or the above monomers are added to polyphenylene ether in the presence of peroxide. A method of heating and grafting a class of molecules can be used.

The most preferred graft copolymer is styrene grafted poly(2,6-dimethyl-1,4-)unilene)ether.

The intrinsic viscosity [η] of the polyphenylene ether used in the composition of the present invention was measured at 30° C. using an Ubbelohde viscometer using chloroform as a solvent.

If the intrinsic viscosity [η] of the polyphenylene ether resin measured in chloroform is less than 0.40, it is not preferable because the crack resistance decreases. If the intrinsic viscosity [η] exceeds 2.0, processability is poor and it is not practical, especially poly 2.6
- For dimethyl phenyl ether, [η] is 1.
If it exceeds 0, the workability will be significantly reduced and it will be impractical, so [η] is preferably in the range of 0.4 or more and less than 1.0.

The styrenic resin referred to in the present invention contains at least 25% by weight of repeating units derived from a vinyl aromatic compound of the general formula
It is something that you have. Here, R1 is hydrogen, a lower alkyl group or a halogen, Z is vinyl, hydrogen, a halogen or a lower alkyl group, and t is an integer of 0 or more. The lower alkyl group herein means an alkyl group having 1 to 6 carbon atoms.

Preferred styrenic resins include, for example, homopolymers such as polystyrene and polychlorostyrene, and rubbery polymers such as polybutadiene, polyisoprene, butyl rubber, EPDM rubber, ethylene-propylene copolymers, natural rubber, polysulfide rubber, polyurethane rubber. ,
Polystyrene modified with epichlorohydrin etc., styrene-containing copolymers such as styrene-acrylonitrile copolymer (SAN), styrene-butadiene copolymer, styrene-maleic anhydride copolymer, styrene-containing copolymer
Acrylonitrile-butadiene copolymer (ABS
>, poly-α-methylstyrene, copolymer of ethylvinylbenzene and divinylbenzene, etc., A-B-A and A-
B-type block copolymer (where A is polystyrene and B is
are elastomeric dienes such as polybutadiene), radial teleblock copolymers of styrene and conjugated dienes, polyolefin-grafted polystyrenes, acrylic resin-modified styrene-butadiene resins, and even blends of homopolystyrene and copolymers of the aforementioned types. included. Most preferred among these are polystyrenes modified with rubbery polymers, so-called rubber-reinforced polystyrenes.

The flame retardant used in the present invention can be obtained by reacting a monofunctional phenol, a polyhydric phenol having the structure shown below, and a halogenated phosphorus compound.

[R is hydrogen or an alkyl group having 1 to 8 carbon atoms, n is a positive integer of 2 or more, and Ar is a phenyl group, an alkyl-substituted phenyl group, or a halophenyl group. ] In the above structural formula, n is a positive integer of 2 or more, and the heat resistance, impact strength, and processability vary depending on the number. The preferred range of n is 2-10. The most preferred number of n is a mixture of 3 to 10, with the center at 6 to 7. R is hydrogen or an alkyl group having 1 to 8 carbon atoms, and has heat resistance,
It is selected based on the balance of workability, etc. Most preferred is hydrogen.

Examples of the monofunctional phenol include phenol, cresol, xylenol, etc., but a mixture of these phenols may also be used. Phenol is particularly preferred from the standpoint of improving impact resistance and crack resistance.

The composition of the present invention is preferably one in which 1 to 25 parts by weight of the flame retardant is added to 10 to 90 parts by weight of a polyphenylene ether resin and 90 to 10 M parts of a styrene resin.

A composition in which 1 to 25 parts by weight of the above flame retardant is added to a composition consisting of 20 to 80 M parts of polyphenylene ether resin and 80 to 20 parts by weight of styrene resin is more preferable from the viewpoint of a balance between processability and heat resistance. .

Particularly when rubber-reinforced polystyrene is used, the higher the amount of rubbery polymer in the composition, the higher the impact strength and crack resistance. It is not preferable because the properties and appearance performance deteriorate, and the amount of the rubbery polymer is 2.5 to 2.5.
Preferably it is in the range of 15% by weight. More preferably, the content is in the range of 2.5 to 8% by weight.

The method for producing the composition of the present invention is not particularly limited, and the composition can be kneaded and produced using a kneader such as an extrusion machine, a heated roll, a Nigu mixer, or a Hanhari mixer.

Of course, the resin composition of the present invention may contain other additives, such as plasticizers, flame retardants, antioxidants, stabilizers such as ultraviolet absorbers, or dyes and pigments. Fillers such as glass fibers, carbon fibers, wollastonite, calcium carbonate, talc, mica, etc. can also be added. Other polymers such as polyamides, polyolefins, polyesters, etc. can also be mixed.

〔Effect of the invention〕

The resin composition of the present invention generates less gas during injection molding, does not generate cracks, and has excellent heat resistance and toughness compared to polyphenylene ether compositions obtained using conventional flame retardants. This makes it possible to develop it into a wider range of applications.

〔Example〕

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Unless otherwise specified, the resin composition was prepared by kneading a mixture of polyphenylene ether resin, styrene resin, and other components in a 30 m+n twin screw extruder at about 250 to 300°C to obtain pellets.

This was injection molded to obtain a test piece, and each physical property value was measured using the following measuring method.

Izot impact strength: ASTM D 256 Heating distortion temperature: ASTM 064B Flame retardancy
: UL94 Tensile strength : ASTM D 638 Insert breaking torque : The metal insert is as shown in Fig. 1 and is made of brass. Vertical 128 with mold temperature 80℃
sga x width 128mm x height 60m+m flesh pressure '2
．． Insert a metal insert into the box-shaped interior of 5a+ga and mold it.Then, as shown in Figure 2, cut out the insert part, immerse it in n-hebutane for 10 minutes at room temperature, dry it, and insert it into a Hios torque meter. Using an H1100 device, an M4 screw was inserted and fastened, and the torque at which the insert would break was measured. The metal M4 screw and the inner groove of the insert are tightened, the insert tries to rotate, and is immersed in n-hebutane, which destroys the crank in it and the insert resin wall that is about to enter. Find the maximum torque and use it as a guideline for insert crank resistance.

Production Example After reacting phenol and phosphorus oxychloride at a molar ratio of 2:1, a compound (I) of the following structural formula obtained by distillation was mixed with an equivalent amount of a polyfunctional phenol compound (If) in the presence of a Lewis acid for 160 ml. A flame retardant (I[[) was obtained by reacting at °C for 10 hours. This flame retardant was a tan solid at room temperature.

(1) (n) n: Mixture of 3 to 10 Example 1 Contains 35 parts by weight of poly2,6-dimethyl-1,4-phenylene ether having an intrinsic viscosity [η] of 0.52 and 11% by weight of polybutadiene Rubber reinforced polystyrene 65
10 parts by weight of the new flame retardant (m) obtained in the production example was kneaded with the weight parts using a twin-screw extruder to obtain pellets. Physical properties were measured using this pellet and are shown in Table 1.

Example 2 In Example 1, 5 parts by weight of the new flame retardant [■] and 5 parts by weight of triphenyl phosphate were used in place of 110 parts by weight of the new flame retardant (I [[]), and pellets were obtained and the physical properties were measured. The results are shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the novel flame retardant (I[[) in Example 1 was replaced with triphenyl phosphate. The results are shown in Table 1.

Comparative Example 2 Except for changing the novel flame retardant (II[) in Example 1 to tricylenyl phosphate (TXP manufactured by Ohe Chemical Co., Ltd.),
Physical properties were measured in exactly the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 Physical properties were measured in the same manner as in Example 1 except that bisphenol A polyphosphate derived from bisphenol A and phosphorus oxychloride was used instead of the novel flame retardant (III) in Example 1, and the results were It is shown in Table 1.

Example 3 The novel flame retardant obtained in the production example was added to 55 parts by weight of poly 2,6-dimethyl-1,4-phenylene ether having an intrinsic viscosity [η] of 0.54 and 45 parts by weight of rubber-reinforced polystyrene with a polybutadiene content of % by weight. [■] 5 parts by weight were kneaded using a twin-screw extruder to obtain pellets. Physical properties were measured using this pellet and are shown in Table 2.

Comparative Examples 4 to 6 Triphenyl phosphate and trixylenyl phosphate (T
The physical properties were measured in exactly the same manner as in Example 3, except that XP), bisphenol A polyphosphate, etc. were used, and the results are shown in Table 2.

Table 1 Table 2

[Brief explanation of drawings]

Figure 1 shows the metal insert used for measuring physical properties and its dimensions; (1-1) is its top view, (1-2) is its side view, and
The figure shows a portion and dimensions cut out from a molded product in which the metal insert of FIG. 1 is inserted into a resin, (2-1) is a plan view of the upper end thereof, and (2-2) is a side view. 1...Metal insert 2...Resin

Claims (1)

[Claims] (1) A resin composition with good flame retardancy, which is a composition consisting of a polyphenylene ether resin, a styrene resin, and a flame retardant, wherein the flame retardant is a phosphorus compound represented by the following general formula. General formula▲ Numerical formula, chemical formula, table, etc.▼ [R is hydrogen or an alkyl group having 1 to 8 carbon atoms, n is a positive integer of 2 or more, and Ar is a phenyl group or an alkyl-substituted phenyl group or a halophenyl group. ]