Polyphenylene ether compositions having improved processability.

This invention relates to polyphenylene ether compositions having improved processability.

Polypheneylene ether is a noteworthy engineering plastics material which is very useful on account of its outstanding electrical and mechanical properties, high heat distortion temperature, and self-extinguishing properties. On the other hand, it has some disadvantages. It is slightly brittle due to low impact resistance. It has a high melting point and a high melt viscosity, and therefore requires a high molding temperature and . pressure. This leads to difficulty in its melt processing.

In order to improve the processability of polyphenylene ether, resin blending has been proposed. For example, Japanese Patent Publication No. 17812/1967 discloses blending a polyphenylene ether with high-impact polystyrene resin. The composition obtained by blending is improved in processability and impact resistance, but the improvement in processability is not satisfactory.

There have been proposed ways of improving the processability of polyphenylene ether by adding a plasticizer.

For example, according to Japanese Patent Publication No. 5220/1974, the processability of polyphenylene ether is improved by incorporating in a polyphenylene ether or a composition of polyphenylene ether and styrene resin a compound selected from aromatic organic acid esters, polyesters having aromatic groups, organic phosphoric esters having aromatic groups, and chlorinated aromatic hydrocarbons which are highly miscible with polyphenylene ether resin.

When incorporating a plasticizer such as organic phosphate ester having aromatic groups,the polyphenylene ether or composition of polyphenylene ether and styrene resin is improved in processability but becomes extremely poor in thermal properties. This is attributable to the fact that the incorporated plasticizer disperses very uniformly into the matrix of the polyphenylene or composition of polyphenylene ether and styrene resin, lowering the glass transition point (Tg) of the matrix and consequently decreasing its heat resistance.,

We postulated that the additive should have the following characteristics if the processability (flowability)was to be improved without sacrificing the thermal performance (heat resistance). <ul id="ul0001" list-style="none"><li>1) It should be highly miscible with the matrix at the time of processing or when the system was in a flowable state, so that it produced the effect of improving flowability like a plasticizer.</li><li>2) It should separate from the matrix when the matrix as not flowing (at a temperature lower than the glass transition point of the matrix), so that it did not lower the Tg of the matrix_': yet it should have a certain degree of miscibility with the matrix, so that it kept a certain level of interface bond strength and kept che mechanical strength even when it had separated from the matrix.</li></ul>

After extensive studies, we have concluded that an additive that satisfies the above two conditions simultaneously should have the following characteristics. <ul id="ul0002" list-style="none"><li>a) It should be a low-molecular weight compound having a consitutuent unit which is miscible with the matrix (polyphenylene ether and styrene resin) and works as a plasticizer at the time of processing or when the system is in the flowable state.</li><li>b) It should crystallize and separate from the matrix phase at a temperature lower than the processing temperature (or the Tg of the matrix).</li><li>c) It should have a comparatively high polarity, so that crystallization occurs with certainty at a temperature lower than the processing temperature.</li><li>d) It should have a unit which has affinity for the matrix (polyphenylene ether and styrene resin) so that it maintains interface bond strength with the matrix even when it crystallizes and separates from the matrix phase.</li></ul>

According to the present invention the processability of a polyphenylene ether composition is improved by the incorporation of a diamide compound represented by the following general formula (I): <chemistry id="chem0001" num="0001"><img file="EP0115218A2_D0001.tif" /></chemistry>wherein R¹ is a C_1-10 linear or branched saturated or unsaturated aliphatic hydrocarbon residue, alicyclic hydrocarbon residue or aromatic hydrocarbon residue, or such a residue having one or more substituents; and R² and R³ are each independently a C_1-10 linear or branched saturated or unsaturated aliphatic hydrocarbon residue, alicyclic hydrocarbon residue or aromatic hydrocarbon residue or such a residue having one or more substituents.

The polyphenylene ether usable in this invention has a repeating structural unit represented by the following general formula (II): <chemistry id="chem0002" num="0002"><img file="EP0115218A2_D0002.tif" /></chemistry>where the ether oxygen atom in one unit is connected to the benzene nucleus of the adjacent unit; n is at least 50; and Q is a monovalent substituent group which is independently selected from hydrogen, halogen, hydrocarbon groups containing no tertiary-α-carbon atom, halohydrocarbon groups having at least two carbon atoms between the halogen atom and the phenyl nucleus, and halohydrocarbon oxygroupshaving at least two carbon atoms between the halogen atom and the phenyl nucleus.

Typical examples of polyphenylene ether include poly(2,6-dimethyl-1,4-phenylene) ether, poly(2,6-diethyl-1,4-phenylene) ether, poly(2-methyl-6-ethyl-1,4-phenylene) ether, poly(2-methyl-6-propyl-1,4-phenylene) ether, poly-(2,6-dipropyl-1,4-phenylene) ether, poly(2-ethyl-6-propyl-1,4-phenylene) ether, poly(2,6-dibutyl-1,4-phenylene) ether, poly(2,6-dipropenyl-1,4-phenylene) ether, poly-(2,6-dilauryl-l,4-phenylene) ether, poly(2,6-diphenyl- l,4-phenylene) ether, poly(2,6-dimethoxy-l,4-phenylene) ether, poly(2,6-diethoxy-l,4-phenylene) ether, poly(2-methoxy-6-ethoxy-l,4-phenylene) ether, poly(2-ethyl-6- stearyloxy-1,4-phenylene) ether, poly(2,6-dichloro-1,4-phenylene) ether, poly(2-methyl-6-phenyl-l,4-phenylene) ether, poly(2,6-dibenzyl-l,4-phenylene) ether, poly(2- ethoxy-1,4-phenylene) ether, poly(2-chloro-1,4-phenylene) ether, and poly(2,5-dibromo-1,4-phenylene) ether.

They also include a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol, a copolymer of 2,6-dimethylphenol and 2,3,5,6-tetramethylphenol, and a copolymer of 2,6-diethylphenol and 2,3,6-trimethylphenol.

The polyphenylene ethers usable in this invention also include modified polyphenylene ethers produced by grafting styrene monomer (such as styrene, p-methylstyrene, and α-methylstyrene) onto the polyphenylene defined by the above-mentioned formula.

The above-mentioned polyphenylene ethers can be produced by such known methods as disclosed in U.S. Patent Nos. 3306874, 3306875, 3257357, and 3257358; Japanese Patent Publication No.17880/1977; and Japanese Patent Laid-open No. 51197/1975.

The groups of the polyphenylene ethers preferred for this invention include one which has an alkyl substituent group at the two ortho positions with respect to the ether oxygen atom; a copolymer of 2,6-dialkylphenol and 2,3,6-trialkylphenol; and a graft polymer obtained by grafting styrene monomer onto the polyphenylene ether skeleton.

The styrene resins usable in this invention include homopolymers such as polystyrene, poly-á-methylstyrene, and poly-p-methylstyrene; high-impact polystyrene modified with butadiene rubber, styrene-butadiene copolymer, ethylene-propylene copolymer, or ethylene-propylene- diene terpolymer; and styrene-butadiene copolymer, styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, and styrene-methyl methacrylate copolymer. The styrene resin is incorporated in an amount of 0 to 2,000 parts by weight, preferably 3 to 500 parts by weight, based on 100 parts by weight of polyphenylene ether resin.

The polyphenylene ether or the composition of polyphenylene ether and styrene resin may incorporate one or more other polymers in order to improve impact resistance.

The polymers to be added are natural or synthetic rubbery polymers. They include, for example, natural rubber, polyisoprene, polybutadiene, styrene-butadiene (block) copolymer, ethylene-propylene copolymer, and ethylene-propylene-nonconjugated diene terpolymer.

Polymers sensitized by the introduction of polar groups can also be used. Examples include the above-mentioned rubbery polymer when sensitized and polyethyelene, ethylene-vinyl acetate copolymer, polypropylene, and other sensitized polyolefin.

The sensitivity can be imparted by grafting to the above-mentioned polymer an unsaturated organic acid or an anhydride thereof (e.g., acrylic acid, methacrylic acid, itaconic acid, and anhydrides thereof) or an unsaturated silane compound (e.g., vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, and propenyltrimethoxy- silane) represented by the formula: RSiR'_n^Y3-n (where R is an ethylenic unsaturated hydrocarbyl or hydrocarbyloxy group; R' is an aliphatic saturated hydrocarbyl group; Y is a hydrolyzable organic group; and n is 0, 1, or 2; and where there are two or three Y's, they may the same or different.), or by changing the above-mentioned graft-modified- rubbery polymer or resinous polymer into an ionomer. (An ionomer is produced by introducing metal ions into the part of the carboxyl groups connected to the graft chains of the polymer.)

The sensitized polymer can also be obtained by block- or random-polymerization of ethylene and vinyl monomer (such as an unsaturated organic acid e.g., acrylic acid, and an ester thereof, having polar group) or vinyl silane.

The rubbery polymer or the polymer provided with sensitivity is incorporated in an amount of 0.5 to 50 wt%, preferably 2 to 4 wt%, based on the weight of the total polymer components.

In the cases where a sensitized polymer is used, it is preferable to add an inorganic filler. Wher^p the sensitivity-provided polymer and an inorganic filler are used in combination with each other, a special structure is formed in which the sensitivity-provided polymer is dispersed in the polyphenylene ether or composition of polyphenylene ether and styrene resin and the inorganic filler is selectively filled into the sensitivity-provided polymer. Such a structure provides outstanding mechanical strength.

The inorganic filler is inorganic powder such as titanium oxide, zinc oxide, talc, clay, calcium carbonate, and silica which are known as fillers for synthetic resins.

The inorganic filler should have an average particle diameter of 0.05 to 1.0 micron. It is used in an amount of 0.5 to 60 wt%, preferably 1 to 45 wt%, based on the weight of the resulting composition.

Other polymers include polyphenylene ether-grafted polyolefin and polystyrene-grafted polyolefin.

The polyphenylene ether-grafted polyolefin can be obtained by grafting glycidylated polyphenylene ether onto a polyolefin having carboxyl group or acid anhydride group on the main chain or side chain thereof. The glycidylated polyphenylene ether can be obtained by reacting polyphenylene ether with epichlorohydrin. The polyolefinshaving carboxyl group or acid anhydride group on the main chain or side chain thereof include , for example, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, maleic anhdyride- modified polypropylene, maleic anhydride-modified polyethylene, and maleic anhydride-modified ethylene-vinyl acetate copolymer.

The polyphenylene ether-grafted polyolefin can also be obtained by grafting polyphenylene ether onto a polyolefin having a glycidyl group on the side chain, such as ethylene-glycidyl methacrylate copolymer, and ethylene-vinyl acetate-glycidyl methcarylate copolymer.

The polyphenylene ether: moiety of-the graft: polymer should preferably have a molecular weight of 5,000 to 100,000, and the number-average molecular weight of the polyolefin chain should be 100 to 100,000, preferably 3,000 to 50,000.

The polystyrene-grafted polyolefin can be obtained by grafting a styrene copolymer onto a polyolefin, said styrene copolymer having a carboxylic acid group or a cyclic acid anhydride group on the main chain or side chain of polystyrene, e.g., styrene-maleic anhydride copolymer, styrene-citraconic anhydride copolymer, styrene-itaconic anhydride copolymer, styrene-asconit anhydride copolymer, styrene-acrylic acid copolymer, and styrene-methacrylic acid copolymer; and said polyolefin having a glycidyl group on the side chain, e.g., ethylene-glycidyl methacrylate copolymer and ethylene-vinyl acetate-glycidyl methacrylate copolymer.

The styrene copolymer having carboxyl group or cyclic acid anhydride group on the main chain or side chain, which is used for producing the polystyrene-grafted polyolefin in this invention, should preferably contain more than 50 wt% of styrene units and more than 3 wt% of carboxyl group units or cyclic acid anhydride units.

The polyolefin having a glycidyl group on the side chain, which is used for synthesis of the graft polymer, should have a number average molecular weight of 1,000 to 100,000, preferably 3,000 to 50,000.

The polyphenylene ether-grafted polyolefin is used in an amount of 0.1 to 50 wt%, preferably 1 to 30 wt%, and the polystyrene-grafted polyolefin is used in an amount of 1 to 80 wt%, preferably 1 to 30 wt%, based on the total polymer such as the total weight of polyphenylene ether or a composition of polyphenylene ether and styrene resin, and polyphenylene ether-grafted polyolefin and/or polystyrene-grafted polyolefin.

The grafted polyolefin may be added after graft polymerization. In the case where a polyolefin having glycidyl groups is used, the grafting reaction can be accomplished by mixing it with polyphenylene ether or styrene resin having a carboxyl group or a carboxylic acid anhydride group at a high temperature above 150°C.

Thus, mixing a polyolefin containing glycidyl groups and polyphenylene ether or a composition of polyphenylene ether and styrene resin at a high temperature brings about the grafting reaction and provides a composition containing polyphenylene ether-grafted polyolefin and/or polystyrene-grafted polyolefin. This method is preferable from an economical point of view.

The diamide compound of the general formula (I) will now be discussed.

Examples of R¹ in the general formula (I) include a methylene group, ethylene group, trimethylene group, propylene group, tetramethylene group, isobutylene group, pentamethylene group, cyclopentylene group, hexamethylene group, cyclohexylene group, octamethylene group, decamethylene group, and phenylene group.

Examples of R² and R³ include a methyl group, ethers group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, isopentyl group, cyclopentyl group, hexyl group, isohexyl group, cyclohexyl group, heptyl group, octyl group, decyl group, and phenyl group.

_R^l, R², and R³ may have one or more substituents. Examples of the substituents include: <tables id="tabl0001" num="0001"><img file="EP0115218A2_D0003.tif" /></tables><ul id="ul0003" list-style="none"><li>-COOH or metal salt thereof or acid anhydride group</li><li>-SO₃H</li><li>-N⁰2</li><li>-NO</li><li>-CN</li></ul>

The diamide compound used in this invention is intended to be miscible with the matrix components when the composition is in the flowablestate for processing; but it is also intended to crystallize and separate from the matrix components when the molded composition is in use. Therefore, the diamide compound used.in this invention should have a melting point slightly lower than the processing temperature.

The processing temperature for the composition of this invention is established between the Tg of the matrix (temperature at which the composition starts to flow) and the temperature at which the composition starts to decompose.

The glass transition point (Tg) of the mixture of polyphenylene ether and styrene resin varies depending on its composition. It is 103°C in the case of a composition of polyphenylene ether (1 part) and high-impact polystyrene (99 parts). Therefore, the processing temperature for a composition of polyphenylene ether and styrene resin is usually higher than 103°C. Polyphenylene ether usually begins to decompose at about 350°C in the air. Thus, the processing is usually carried out at 105°C to 350°C.

Accordingly, the diamide compound used in this invention should have a melting point higher than 105°C, preferably higher than 130°C, particularly 130°C to 350°C. A diamide having a melting point lower or higher than the above-mentioned limit may be used in the case where the processing temperature becomes lower or higher than the above-mentioned limit due to the addition of atabilizer or plasticizer. The diamide compound is added in an amount of 0.1 to 25 parts by weight, preferably 0.5 to 20 parts by weight, particularly 2 to 10 parts by weight, based on 100 parts by weight of total polymers.

The composition of this invention may incorporate other additives according to the intended end use.

The additives include stabilizer, plasticizer, flame-retardant, inorganic filler, mold release, and colorant_i and the polyphenylene ether compositons of this invention have improved flowability and are easy to process even when other additives are added.

Those additives which are most commonly used for the polyphenylene ether compositions of this invention are stabilizers, colorants, and flame-retardants. Popular flame-retardants include, for example, phosphoric esters such as trimethyl phosphate, triethyl phosphate, tri- propylphosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(chloroethyl) phosphate, tris(dichloroethyl) phosphate, tris(bromoethyl) phosphate, tris(dibromoethyl) phosphate, tris(chlorophenyl) phosphate, tris(dichlorophenyl) phosphate, tris(bromophenyl) phosphate, and tris(dibromophenyl) phosphate; halogenated aromatic derivatives such as hexabromobenzene, pentabromotoluene, and decabromobiphenyl; antimony compounds such as triphenylantimony, tris(bromophenyl)-antimony, tris(dibromophenyl)antimony, and antimony oxide; and halides such as halogenated diphenyl carbonate, halogenated cyclodecane, halogenated phthalic acid anhydride, and halogenated polystyrene.

The polyphenylene ether composition is improved in both flame retardancy and heat resistance when the above-mentioned flame-retardant is used in combination with a bicyclophosphate ester represented by the following general formula: <chemistry id="chem0003" num="0003"><img file="EP0115218A2_D0004.tif" /></chemistry>where ℓ is an integer of 0 to 2; m is an integer of 1 to 3; n is an integer of 1 to 3; and R is hydrogen or a C₁-_lg alkyl group or derivative thereof.

Examples of this compound include 2,6-trioxano-l-phosphobicyclo[2,2,2]octane-l-oxide, 2,6,7-trioxano-l-phosphobicyclo[2,2,2]octane-4-methyl-l-oxide, and 2,6,7- trioxano-l-phosphobicyclo[2,2,2]octane-4-hexadecyl-l-oxide.

These flame retardants may be used individually or in combination with one another.

The invention is now described in more detail with reference to the following Examples and Comparative Examples.

EXAMPLE 1 and COMPARATIVE EXAMPLE 1

The following components were melted and mixed at 260°C for 7.5 minutes by using a Brabender. 50 parts by weight of poly-2,6-dimethyl-1,4-phenylene ether (having an intrinsic viscosity of 0.50 measured in chloroform at 25°C; made by Mitsubishi Petrochemical Co., Ltd.). 50 parts by weight of high-impact polystyrene (465D, a product of Asahi Dow Co., Ltd.). 5 parts by weight of N,N'-diphenyladipic acid diamide (having a melting point of 235°C as measured with the melting point measuring apparatus MP-1 made by Yamato

Kagaku Co., Ltd.).

After mixing was complete, the melt index at 250°C under a load of 10 kg was measured, which indicates the processability (flowability) of the composition. The composition was press-formed into test pieces for measurement of heat distortion temperature under a load of 18.6 kg/_cm2.

In Comparative Example 1, the diamide was not used. The results are shown in Table 1 and Fig. 1 in which the melt index is plotted against the heat distortion temperature.

EXAMPLES 2 TO 5 AND COMPARATIVE EXAMPLES 2 TO 5

The same experiments as in Example 1 and Comaprative Example 1 were carried out except the ratio of poly-2,6-dimethyl-1,4-phenylene ether to high-impact polystyrene was changed as follows: <ul id="ul0004" list-style="none"><li>70/30 (Example 2 and Comparative Example 2),</li><li>60/40 (Example. 3 and Comparative ExampLe 3),</li><li>40/60 (Example 4 and Comparative Example 4), and</li><li>30/70 (Example 5 and Comparative Example 5).</li></ul>

The results are shown in Table 1 and Fig. 1. It is noted in Table 1 that the composition is remarkably improved in flowability by adding 5 parts of N,N'-diphenyladipic acid diamide.

<tables id="tabl0002" num="0002"><img file="EP0115218A2_D0005.tif" /></tables>

Line A obtained by plotting the data of Comparative Examples 1 to 5 indicates how the flowability (melt index) is related with the heat resistance (heat distortion temperature) when the ratio of poly-2,6_-dimethyl-2,4-phenylene ether to high-impact polystyrene is changed continuously.

In other words, line A indicates that as the ratio of high-impact polystyrene is increased, the flowability (melt index) increases but the heat distortion temperature decreases.

On the other hand, line B obtained by plotting the data in Examples 1 to 5 lies above line A. This apparently indicates the effect of this invention.

EXAMPLES 6 to 13 and

COMPARATIVE EXAMPLES 6 to 10

In Examples 6 to 13, the same experiments as in Example- 1 were carried out except the quantity of N,N'- diphenyladipic acid diamide was changed to 0.5, 1, 3, 8, 10, 12, 15, and 20 parts by weight. The results are shown in Table 2 and Fig. 2.

In Comparative Example 6 to 10, N,N'-diphenyladipic acid diamide was replaced by triphenyl phosphate in an amount of 2, 3, 5, 7, and 10 parts by weight. It is a plasticizer which is known to produce the effect of improving the flowability of polyphenylene ether or a composition of polyphenylene ether and styrene resin. The results are shown in Table 2 and Fig. 2.

Fig. 2 is based on the data in Table 2. In Fig. 2, the flowability (melt index) is plotted against the heat resistance (heat distortion temperature). The superscripts indicate the quantity of N,N'-diphenyl adipic acid diamide or triphenyl phosphate added.

Triphenyl phosphate is a well-known flame retardant as well as a plasticizer. As the addition of this compound is increased, the composition greatly improves in processability (flowability) but decreases in heat resistance (heat distortion temperature). See line C in Fig. 2.

On the other hand, line D in Fig. 2 indicates that as N,N'-diphenyl adipic acid diamide is added more, the flowability is greatly improved with a minimum of decrease in heat resistance (heat distortion temperature). <tables id="tabl0003" num="0003"><img file="EP0115218A2_D0006.tif" /></tables>

EXAMPLE 14

Example 1 was repeated except that N,N'-diphenyl- adipic acid diamide was replaced by 5 parts by weight of N,N'-dihexyladipic acid diamide (having a melting point of 158°C as measured by MP-21 made by Yamato Kagaku Co., Ltd.). The results are shown in Table 3.

EXAMPLE 15

Example 1 was repeated except that N,N'-diphenyl- adipic acid diamide was replaced by 5 parts by weight of N,N'-dihexylterephthalic acid diamide (having a melting point of 204°C as measured by MP-21 made by Yamato Kagaku Co., Ltd.). The results are shown in Table 3.

EXAMPLE 16

Example 1 was repeated except that N,N'-diphenyl- adipic acid diamide was replaced by 5 parts by weight of N,N'-dihexylsuccinic acid diamide (having a melting point of 226°C as measured by MP-21 made by Yamato Kagaku Co., Ltd.). The results are shown in Table 3.

EXAMPLE 17

Example 1 was repeated except that N,N'-diphenyl- adipic acid diamide was replaced by 5 parts by weight of N,N'-dihexylsebacic acid diamide (having a melting point of 196°C as measured by MP-21 made by Yamato Kagaku Co., Ltd.). The results are shown in Table 3. <tables id="tabl0004" num="0004"><img file="EP0115218A2_D0007.tif" /></tables>

EXAMPLE 18 and COMPARATIVE EXAMPLE 11

The following components were dry-blended by using a supermixer, and then mixed and pelletized at 340°C by using a twin-screw extruder (PCM-45φ) made by Ikegai Iron Works, Ltd.

60 parts by weight of poly-2,6-dimethyl-l,4-phenylene ether (having an intrinsic viscosity of 0.50 measured in chloroform at 25°C; made by Mitsubishi Petrochemical Co., Ltd.). 40 parts by weight of high-impact polystyrene (HT-76, a product of Mitsubish Monsanto Co., Ltd.). 5 parts by weight of N,N'-diphenylterephthalic acid diamide (having a melting point of 337°C as measured with the melting point measuring apparatus MP-21 made by Yamato Kagaku Co., Ltd.).

The resulting pellets were injection-molded at a temperature of 340°C under an injection pressure of 1000 kg/cm² by using an injection molding machine N-100 (made by The Japan Steel Works, Ltd.) to measure the flow distance in a spiral cavity, 2 mm thick and 8 mm wide. Test pieces for measuring heat distortion temperature were also formed by using the same injection molding machine as above.

In Comparative Example, the same experiments as in Example were carried out except that N,N'-diphenyltere- phthalic acid diamide was not used. The results are shown in Table 4.

EXAMPLE 19

Example 18 was repeated except that N,N'-diphenyl- terephthalic acid diamide was replaced by N,N'-diphenyl- fumaric acid diamide (having a melting point of 314°C as measured with the melting point measuring apparatus MP-21 made by Yamato Kagaku Co., Ltd.). The results are shown in Table 4. <tables id="tabl0005" num="0005"><img file="EP0115218A2_D0008.tif" /></tables>

EXAMPLES 20 to 26 and

COMPARATIVE EXAMPLES 12 to 14

The following components were dry-blended in the ratio shown in shown in Table 5 by using a supermixer, and then mixed and pelletized at 280°C by using a twin-screw extruder (PCM-45ø) made by Ikegai Iron Works, Ltd. Poly-2,6-dimethyl-1,4-phenylene ether (having an intrinsic viscosity of 0.47 measured in chloroform at 30°C; made by Mitsubishi Petrochemical Co., Ltd.). <ul id="ul0005" list-style="none"><li>Polystyrene (HF-77, a product of Mitsubish Monsanto Co., Ltd.),</li><li>Maleic anhydride-grafted ethylene-propylene copolymer (containing 1.5 wt% of maleic acid anhydride; made by Mitsubishi Petrochemical Co., Ltd.).</li><li>Styrene-butadiene copolymer (1502, a product of Japan Synthetic Rubber Co., Ltd.),</li><li>Precipitated calcium carbonate (having an average particle diameter of 0.2 micron), and</li><li>N,N'-diphenyladipic acid diamide.</li></ul>

The resulting pellets were injection-molded at a temperature of 300°C under an injection pressure of 1100 kg/cm² by using an injection molding machine N-100 (made by The Japan Steel Works, Ltd.) to measure the flow distance in a spiral cavity, 2 mm thick and 8 mm wide. Test pieces for measuring heat distortion temperature were also formed by using the same injection molding machine as above.

In Comparative Examples, the same experiments as in Examples were carried out except that N,N'-diphenyladipic acid diamide was not used. The results are shown in Table 5 and Fig.3.

In Fig. 3, the flowability (spiral flow distance) is plotted against the heat resistance (heat distortion temperature) based on the data in Table 5. Curve E was obtained by plotting the data in Comparative Examples 12, 13, and 14 in which N,N'-diphenyladipic acid diamide was not used. In this case, the flowability of the composition can be changed by the mixing ratio of poly-2,6-dimethyl-l,4-phenylene ether and polystyrene, but its extent is limited. On the other hand, the curve is shifted rightward when N,N'-diphenyl adipic acid diamide is added. (Curve F for Examples 20 and 21; curve G for Examples 22 to 24; and curve H for Examples 25 and 26) This suggests that the composition of this invention is greatly improved in flowability with no loss of heat resistance. <tables id="tabl0006" num="0006"><img file="EP0115218A2_D0009.tif" /></tables>

EXAMPLES 27 and 28 and

COMPARATIVE EXAMPLES 15 and 16

The following components were uniformly blended in the ratio shown in Table 6 by using a supermixer, and then mixed for grafting at 280°C and pelletized by using a twin-screw extruder (PCM-45φ) made by Ikegai Iron Works, Ltd. <ul id="ul0006" list-style="none"><li>Poly-2,6-dimethyl-l,4-phenylene ether (having an intrinsic viscosity of 0.48 as measured in chloroform at 30°C; made by Mitsubishi Petrochemical Co., Ltd.),</li><li>Polystyrene (HF-77, a product of Mitsubish Monsanto Co., Ltd.),</li><li>Ethylene-vinyl acetate-glycidyl methacrylate copolymer (MFR = 4, containing 5 wt% of vinyl acetate and 10 wt%</li><li>of glycidyl methacrylate; made by Mitsubishi Petrochemical Co. Ltd.), ,</li><li>Sytyrene-maleicranhydride copolymer (containing 10 wt%</li><li>of maleic acid anhydride), made by Arcopolymer Co., Ltd.), and</li><li>N,N'-diphenyladipic acid diamide.</li></ul>

The resulting pellets were injection-molded in the same way as in Example 20 to measure the flow distance (spiral flow) and heat distortion temperature.

In Comparative Examples, the same experiments as in Examples were carried out except that N,N'-diphenyladipic acid diamide was not used. The results are shown in Table 6 and Fig.4.

In Fig. 4, the flowability (spiral flow distance) is plotted against the heat resistance (heat distortion temperature) based on the data in Table 6. Curve I - was obtained by plotting the data in Comparative Examples 15 and 16 in which N,N'-diphenyladipic acid diamide was not used, and curve J was obtained by plotting the data in Examples 27 and 28. These results suggest that the composition of this invention-is greatly improved in flowability with no loss of heat resistance. <tables id="tabl0007" num="0007"><img file="EP0115218A2_D0010.tif" /></tables>

EXAMPLE 29 and COMPARATIVE EXAMPLE 17

The following components were uniformly blended in the ratio shown in Table 7 by using a supermixer, and then mixed at 280°C and pelletized by using a twin-screw extruder (PCM-45φ) made by Ikegai Iron Works, Ltd. Poly-2,6-dimethyl-l,4-phenylene ether (having an intrinsic viscosity of 0.47 measured in chloroform at 30°C; made <ul id="ul0007" list-style="none"><li>by Mitsubishi Petrochemical Co., Ltd.),</li><li>Polystyrene (HF-77, a product of Mitsubish Monsanto Co., Ltd.),</li><li>Maleic anhdyride-grafted ethylene-propylene copolymer (containing 1-5 wt% of maleic anhydride; made by Mitsubishi Petrochemical Co., Ltd.),</li><li>Styrene-butadiene copolymer (1502, a product of Japan Synthetic Rubber Co., Ltd.),</li><li>Precipitated calcium carbonate (average particle diameter 0.2 micron),</li><li>Triphenyl phosphate (flame retardant), and</li><li>N,N'-diphenyladipic acid diamide.</li></ul>

The resulting pellets were injection-molded at a temperature of 300°C under an injection pressure of 1100 kg/cm² by using an injection molding machine N-100 (made by The Japan Steel Works, Ltd.) to measure the flow distance in a spiral cavity, 2 mm thick and 8 mm wide. Test pieces were formed by using the same injection molding machine as above, for evaluating the flame retardance according to UL Standards, Subject 94.

In Comparative Example, the same experiments as in Example were carried out except that N,N'-diphenyladipic acid diamide was not used. The results are shown in Table 7. These results suggest that the addition of N,N'-diphenyladipic acid diamide greatly improves the- flowability of the composition without any adverse effect on flame retardance. <tables id="tabl0008" num="0008"><img file="EP0115218A2_D0011.tif" /></tables>

EXAMPLE 30 and COMPARATIVE EXAMPLE 18

The following components were uniformly blended in the ratio shown in Table 8 by using a supermixer, and then mixed at 280°C and pelletized-by using a twin-screw extruder (PCM-45φ) made by Ikegai Iron Works, Ltd. Poly-2,6-dimethyl-1,4-phenylene ether (having an intrinsic viscosity of 0.45.measured in chloroform at.30°C; made <ul id="ul0008" list-style="none"><li>by Mitsubishi Petrochemical Co., Ltd.),</li><li>Polystyrene (HF-77, a-product of Mitsubish Monsanto Co., Ltd.),</li><li>Maleic anhydride-grafted ethylene-propylene copolymer (containing 1.5 wt% of maleic anhydride; made by Mitsubishi Petrochemical Co., Ltd.),</li><li>Styrene-butadiene copolymer (1502, a product of Japan Synthetic Rubber Co., Ltd.),</li><li>Precipitated calcium carbonate (average particle diameter 0.2 micron),</li><li>2,6,7-trioxa-l-phosphobicyclo[2,2,2]octane-4-ethyl-l-oxide (flame retardant), and</li><li>N,N'-diphenyladipic acid diamide.</li></ul>

The resulting pellets were injection-molded at a temperature of.300°C under an injection pressure of 1100 kg/cm² by.using an injection molding machine N-100 (made by The Japan Steel Works, Ltd.) to measure the flow distance in a spiral cavity, 2 mm thick and 8 mm wide. Test pieces were formed by using the same injection molding machine as above, for evaluating the flame retardance according to UL Standards, Subject 94.

In Comparative Example, the same experiments as in Example were carried out except that N,N'-diphenyladipic acid diamide was not used. The results are shown in Table 8. These results suggest that the addition of N,N'-diphenyladipic acid diamide greatly improves the flowability of the composition without any adverse effection flame retardance. <tables id="tabl0009" num="0009"><img file="EP0115218A2_D0012.tif" /></tables>