JPH07268202A - Flame-retardant polyphenylene ether resin composition improved in light resistance - Google Patents

Abstract

PURPOSE:To obtain a flame-retardant polyphenylene ether resin composition improved in light resistance and flame retardancy and free from discoloration during molding by incorporating a specified light stabilizer and a specified phosphate flame retardant into a polyphenylene ether resin or its mixture with a polystyrene. CONSTITUTION:This composition consists of 100 pts.wt. polyphenylene ether resin having a main chain of a structure of formula I (wherein R<1> is 1-3C alkyl; and R<2> and R<3> are each H or 1-3C alkyl) alone or mixture of this resin with a polystyrene resin, 0.01-10 pts.wt. light stabilizer comprising hydroxybenzotiazole and hindered amine compounds, and 1-30 pts.wt. bisphenol A-bmsphosphate of formula II (wherein R<4> and R<5> are each 1-6C alkyl or phenyl). Examples of the light stabilizer include methylhydroxyphenylbenzotriazole, etc., and bis(tetramethylpiperidine) sebacate, etc., wherein the use of 0.2-2 pts.wt. of the former compound in combination with 0.2-2 pts.wt. of the latter is desirable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene ether resin composition which is excellent in light resistance, flame retardancy, heat resistance and mechanical strength and which is prevented from discoloration during molding retention.
More specifically, a resin composition of a polyphenylene ether-based resin or a polyphenylene ether-based resin and a polystyrene-based resin is blended with a specific light resistance stabilizer and a specific phosphoric acid ester-based flame retardant to improve light resistance. The present invention relates to a flammable polyphenylene ether resin composition.

[0002]

2. Description of the Related Art Polyphenylene ether resin is an engineering plastic excellent in various properties such as thermal properties, mechanical properties and electrical properties. However, since the polyphenylene ether resin has a high melt viscosity, it is inferior in moldability and impact resistance. For the purpose of improving the molding processability and impact resistance, a technique of blending a styrene resin or a rubber-modified styrene resin and various elastomers is disclosed in US Pat. No. 3,383,4.
It is disclosed in various documents such as the specification No. 35. Such a thermoplastic resin composition is known to be capable of being molded into a molded product having good properties as a whole. However, when such a polyphenylene ether resin composition is used outdoors or in an environment exposed to light through a window, its performance decreases as the exposure time increases, and especially the color changes greatly, and the light resistance is increased. It is hard to say that it has excellent properties. Also, the flame retardancy is not sufficient.

Several methods for improving the light resistance of polyphenylene ether resin compositions have been proposed. For example, Japanese Patent Publication No. 56-501881 discloses a polyphenylene ether resin composition containing a piperidine derivative having a specific structural formula alone or a combination of a piperidine derivative and phosphite, hydroxybenzotriazole or a sterically hindered phenol. Kaisho 55-1
No. 35159 discloses a stabilizer for a polyphenylene ether-based graft copolymer resin composition comprising an organic phosphite compound and hydroxybenzotriazoles,
Japanese Unexamined Patent Publication (Kokai) No. 50-100153 discloses a polyphenylene ether resin composition containing oxybenzotriazoles, oxybenzophenones and an organic nickel complex.

In order to impart flame retardancy to the polyphenylene ether resin composition, a method of blending a phosphorus flame retardant is known. For example, JP-A-49-32947, JP-A-53-73248, and JP-A-55-16.
It has been proposed to blend an aromatic phosphate ester or an aromatic phosphate ester polymer in various documents such as JP-A-0881, JP-A-57-30737 and JP-A-55-118957. However, generally, in a polyphenylene ether-based resin composition having improved light resistance, when a flame retardant is added at the same time to impart flame retardancy, light resistance is reduced, discoloration due to retention during molding, or a volatile component of the resin composition. Contamination of the mold due to
Furthermore, there was a problem such as deterioration of the appearance of the molded product.

[0005]

By adding a specific light resistance stabilizer and a specific phosphoric acid ester flame retardant to a resin composition comprising a polyphenylene ether resin or a combination thereof with a polystyrene resin, excellent results can be obtained. It is intended to obtain a flame-retardant polyphenylene ether-based resin composition which has light resistance and flame retardancy at the same time and which is not discolored due to retention during molding.

[0006]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a resin composition comprising a polyphenylene ether resin or a polystyrene resin to satisfy both light resistance and flame retardancy. It has been found that the above-mentioned problems can be solved by adding a specific light resistance stabilizer and a specific phosphate ester flame retardant to the composition, and the present invention has been completed. That is, the present invention comprises (a) a polyphenylene ether resin alone or a mixture with a polystyrene resin, (b) a light resistance stabilizer, and (d) a phosphoric acid ester flame retardant. The present invention provides a satisfactory polyphenylene ether resin composition.

The polyphenylene ether resin used as the component (a) of the resin composition of the present invention has the general formula 3

[Chemical 3] (In the formula, R1 is a lower alkyl group having 1 to 3 carbon atoms, R2,
R3 represents a hydrogen atom or a lower alkyl group having 1 to 3 carbon atoms. ) A polymer having a structural unit represented by the formula) in its main chain, which may be a homopolymer or a copolymer. Specifically, for example, poly (2,6-dimethyl-
1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether, poly (2-
Methyl-6-ethyl-1,4-phenylene) ether,
Examples thereof include poly (2-methyl-6-propyl-1,4-phenylene) ether, and especially poly (2,6-
Dimethyl-1,4-phenylene) ether and 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer are preferred.

Further, a polystyrene resin which can be mixed with the polyphenylene ether resin used as the component (a) is represented by the following general formula 4

[Chemical 4] (In the formula, R6 represents a hydrogen atom or a lower alkyl group, Z2 represents a halogen atom or a lower alkyl group, and p represents 0 to 5).
Is an integer. ) A resin containing at least 25% or more of the structural unit represented by) in its polymer, and examples thereof include polystyrene, high-impact polystyrene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, and styrene-α-methyl. Examples thereof include a styrene copolymer, a styrene-maleic anhydride copolymer, an ethylene-styrene copolymer, an ethylene-propylene-butadiene-styrene copolymer and the like. Here, as the impact-resistant polystyrene, polybutadiene, butadiene-styrene copolymer rubber or E
Polystyrene modified with a rubber component such as PDM is included. The polystyrene resin used in the resin composition of the present invention has a weight average molecular weight of 1,000 to 5 by GPC.
0,000, preferably 3,000 to 300,000
Is.

At least one compound selected from hydroxybenzotriazoles and / or hindered amines is used as the light resistance stabilizer which is the component (b) used in the present invention. Specifically, first, as hydroxybenzotriazoles, 2- (5-methyl-2-
Hydroxyphenyl) benzotriazole, 2- [2-
Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl-2H-benzotriazole, 2- (3,
5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2)
-Hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3
Examples thereof include 5-di-t-amyl-2-hydroxyphenyl) benzotriazole and 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole. In particular, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl-2H-benzotriazole, 2- (3-t-butyl-5-methyl-).
2-Hydroxyphenyl) -5-chlorobenzotriazole is preferred.

Next, hindered amines include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2. , 3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis (2,2,6 6-pentamethyl-4-piperidyl) sebacate and the like. In particular, bis (2,2,6,6-tetramethyl-
4-piperidyl) sebacate, bis (2,2,6,6-
Pentamethyl-4-piperidyl) sebacate is preferred.

These may be used alone or in combination as required, but it is particularly preferable to use hydroxybenzotriazoles and hindered amines in combination.
When these are used in combination, 0.1 to 3 parts by weight of hydroxybenzotriazoles and 0.1 to 0.1 of hindered amines are used.
A combination of 3 parts by weight, preferably 0.2 to 2 parts by weight of hydroxybenzotriazoles and 0.2 to 2 parts by weight of hindered amines, is particularly preferable because the light resistance is efficiently improved.

The compounding amount of the above compound in the resin composition of the present invention may be selected within the range of 0.01 to 10 parts by weight with respect to 100 parts by weight of the component (a) in the resin composition. The amount is preferably 0.05 to 7 parts by weight, more preferably 0.1 to 5 parts by weight. Even if it is used over the upper limit, not only the light resistance stability of the polyphenylene ether-based resin composition is not improved so much, but also undesired effects such as decrease in mechanical strength and deflection temperature under load of the resin composition are observed. Further, if the amount added is less than the lower limit, no improvement in the light resistance of the resin composition is observed.

As the phosphate ester flame retardant which is the component (c) used in the present invention, bisphenol A-bisphosphates represented by the general formula 5 are used.
Bisphenol A-bisphosphates are condensation type phosphoric acid esters that generate little gas at high temperatures and have excellent light resistance.

[Chemical 5] (In the formula, R4 and R5 are lower alkyl groups having 1 to 6 carbon atoms,
A phenyl group or an alkyl-substituted phenyl group is shown. )

Although monophosphates such as triphenyl phosphate and tricresyl phosphate are excellent in light resistance, they generate a large amount of gas at high temperatures and may cause deposits on the mold during molding. In addition, as a condensation type phosphoric acid ester that generates less gas at high temperatures, 1,3
-Phenylene-bis (diphenyl phosphate) is known, but this compound is inferior in light resistance, and further, when amines are present at a high temperature, coloration is not preferable.

The amount of the above-mentioned phosphate ester flame retardant compounded is 1 to 30 parts by weight per 100 parts by weight of the component (a),
It is preferably 3 to 20 parts by weight. If the content exceeds the upper limit, the flame retardancy does not change, and the mechanical strength etc. are only impaired. If it is below the lower limit, the flame retardancy is insufficient. The resin composition of the present invention, depending on the purpose, other additives, for example,
Plasticizers, lubricants, stabilizers, pigments, dyes, mold release agents and fillers such as glass fibers, glass beads, carbon fibers, mica, talc, clay and calcium carbonate can be added. There is no particular limitation on the method of mixing the components constituting the present invention, and for example, a method of kneading with an extruder, a heating roll, a Banbury mixer, a kneader or the like is appropriately selected.

[0016]

EXAMPLES The resin composition of the present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In addition, the number of parts of the constituent components of the resin composition is represented by weight unless otherwise specified. Example 1 Intrinsic viscosity of 0.45 measured in chloroform at 25 ° C.
64 parts by weight of poly (2,6-dimethyl-1,4-phenylene) ether of dl / g, high-impact polystyrene (trade name: Dialex HT-47, manufactured by Mitsubishi Kasei Co., Ltd.)
8) 27 parts by weight, 9 parts by weight of bisphenol A-bis (dicresyl phosphate) as a flame retardant, and 2- (3-t-butyl-5--5) as a benzotriazole-based light stabilizer.
Methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (Ciba Geigy, trade name Tinuvin 32
6) 0.5 parts by weight, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (manufactured by Ciba Geigy, trade name Tinuvin 77 as a hindered amine light stabilizer.
0) 1 part by weight, 0.5 part by weight of zinc oxide, and 3 parts by weight of titanium oxide for adjusting the color to white are mixed with a Henschel mixer, and then a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., TEM).
35), and the pellets obtained by melt-kneading at a temperature of 280 ° C. are injection molding machines (J50 manufactured by Japan Steel Works, Ltd.).
Various test pieces were molded at E-P and a cylinder temperature of 280 ° C. The results of measurement using these test pieces are shown in Table 1.

Various tests were conducted according to the following methods. 1) Flame Retardancy A test piece having a thickness of 1/16 inch was used according to UL94 standard, and the burning time was measured and evaluated. 2) Retention discoloration Using a J50E-P injection molding machine manufactured by Japan Steel Works, Ltd., the test specimen was injection-molded after being retained in the cylinder for 20 minutes at a cylinder temperature of 280 ° C., and the discoloration was visually observed. It was judged by and displayed as follows. ×: Large discoloration Δ: Slightly discoloration ○: No discoloration 3) Heat loss Using a differential thermal balance (manufactured by DuPont), the temperature was raised from room temperature to 300 ° C. at 20 ° C./min.
The weight when kept at 30 ° C. for 30 minutes is represented by the weight loss rate. 4) Light resistance test Xenon light resistance tester (manufactured by Atlas Co., Ltd., Ci35
In A), the change in color difference after 300 hours of exposure is measured with a color difference meter (SM-3, manufactured by Suga Test Instruments Co., Ltd.) and represented by ΔE.

Example 2 Various test pieces were molded by repeating the same operation as in Example 1 except that bisphenol A-bis (diphenyl phosphate) was used as the flame retardant. The results of measurement using these test pieces are shown in Table 1.

Example 3 As a light fastness stabilizer, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (manufactured by Ciba-Geigy, trade name Tinuvin), which is a benzotriazole-based light fastness stabilizer, is used. 326) The same operation as in Example 1 was repeated except that only 1.5 parts by weight was used to mold various test pieces. The results of measurement using these test pieces are shown in Table 1.

Example 4 As a light resistance stabilizer, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate (manufactured by Ciba Geigy, trade name Tinuvin 77) which is a hindered amine light resistance stabilizer.
0) The same operation as in Example 1 was repeated except that only 1.5 parts by weight was used to mold various test pieces. The results of measurement using these test pieces are shown in Table 1.

Comparative Example 1 Example 1 with the flame retardant being replaced by triphenyl phosphate
The same operation as above was repeated to form various test pieces. The results of measurement using these test pieces are shown in Table 1.

Comparative Example 2 Example 1 was replaced with tricresyl phosphate as the flame retardant.
The same operation as above was repeated to form various test pieces. The results of measurement using these test pieces are shown in Table 1.

Comparative Example 3 The same operation as in Example 1 was repeated except that 1,3-phenylene-bis (diphenylphosphate) was used as the flame retardant.
Various test pieces were molded. The results of measurement using these test pieces are shown in Table 1.

[0024]

[Table 1] Flame retardance, retention discoloration, heating loss (%) Light resistance test (ΔE) Example 1 V-0 ○ 3 3.0 Example 2 V-0 ○ 4 3.5 Example 3 V-0 ○ 4 3.8 Example 4 V-0 ○ 3 4.2 Comparative Example 1 V-0 ○ 14 3.0 Comparative Example 2 V-0 ○ 13 3.1 Comparative Example 3 V-0 × 8 8.3

[0025]

EFFECTS OF THE INVENTION The resin composition of the present invention has excellent flame retardancy, light resistance, high temperature stability and light color by blending a specific phosphate ester flame retardant and a specific light resistance stabilizer. Even if it is toned, it does not change color during high temperature molding,
It is easy to use after adjusting to various colors and is industrially useful.

Claims (2)

[Claims] 1. (a) 100 parts by weight of a polyphenylene ether resin alone or a mixture of a polyphenylene ether resin and a polystyrene resin having a structural unit represented by the general formula 1 in the main chain: (In the formula, R1 is a lower alkyl group having 1 to 3 carbon atoms, R2,
R3 represents a hydrogen atom or a lower alkyl group having 1 to 3 carbon atoms. ) (B) 0.01 to 10 parts by weight of a light resistance stabilizer comprising at least one compound selected from the group consisting of hydroxybenzotriazoles and hindered amines, and (c) bisphenol A represented by the general formula 2. -A polyphenylene ether resin composition comprising 1 to 30 parts by weight of a bisphosphate. [Chemical 2] (In the formula, R4 and R5 are lower alkyl groups having 1 to 6 carbon atoms,
A phenyl group or an alkyl-substituted phenyl group is shown. ) 2. The polyphenylene ether according to claim 1, wherein (b) the light fastness stabilizer comprises both 0.1 to 3 parts by weight of hydroxybenzotriazoles and 0.1 to 3 parts by weight of hindered amines. -Based resin composition.