Stabilized polyphenylene sulfide and method for producing same

Claim 1

A stabilized polyphenylene sulfide which comprises a recurring unit,. wherein the average n between foreign units is greater than about 5, and about 0.05 to about 10 mole % per phenylene sulfide unit of an aromatic constituent chemically bonded with said polyphenylene sulfide chain, said aromatic constituent containing an electron attractive group selected from the group consisting of -halogen, -S02-, -CO-, -N0 2 , -S0 3 R, -COOR, wherein R is H, lower aliphatic hydrocarbon groups, aromatic hydrocarbon groups or alkaline metals, and -CONH-, and said stabilized polyphenylene sulfide has a melting point in the range of about 250°C to about 350°C.

Claim 7

A method of preparing a stabilized polyphenylene sulfide according to any of the claims 1 to 5, which comprises preparing a polyphenylene sulfide consisting mainly of a recurring unit wherein the degree of polymerization of said recurring unit is greater than about 20, and reacting said polyphenylene sulfide with 0.05 to 20 mole % per said phenylene sulfide unit of a halogenated aromatic compound having an electron attractive substituent.

Claim 10

The method of any of the claims 6 to 8, wherein said halogenated aromatic compound having an electron attractive substituent is selected from the group consisting of

Claim 11

The method of any of the claims 6 to 9, wherein said halogenated aromatic compound having an electron attractive substituent is introduced into the polymerization system during preparation of said polyphenylene sulfide. of the aromatic ring, may serve as a measure of the electron attractivity. For the electron attractive substituent as described above, those represented by -SO 2 , -CO-, -N0 2 , -CN, -S0 3 R, wherein R represents H, low aliphatic hydrocarbon groups, aromatic hydrocarbon groups or alkaline metals, and -CONH-, are preferable, and halogens, especially chlorine, may be utilized as the electron attractive group. Examples of the aromatic constituents having the electron attractive substituents and contained in the stabilized polyphenylene sulfide of the present invention include: In the stabilized polyphenylene sulfide of the present invention, the aromatic constituents having the electron attractive substituents must be present in the chain ends or branched chains or in the main chain in order to provide the best stabilizing efficiency. A comparable Where the polymerization of the polyphenylene sulfide is effected by reacting dichlorobenzene and sodium sulfide, with N-methyl-pyrrolidone as the solvent, the molar ratio of the monomers may be in the range of 0.90-1.20, and the reaction may be carried out under pressurized conditions at 250-280°C after dehydration of the system. The chain length in the polymer during the reaction or after reaction may be determined by measurement of the molecular weight of the isolated polymer. The aromatic halogen compound containing the electron attractive group may be added to the reaction system during stirring, in the course of polymerization, after completion of polymerization, or after isolation of the polymer, but reaction within several hours in the temperature range of about 150 to 280°C is preferable. In the above-described reaction, the optimum amount of aromatic halogen compound containing the electron attractive group to be added is in the range of about 0.05-20 mole % per polyphenylene sulfide constituting unit. If the amount added is in excess of this range, recovery is undesirably effected in the unreacted state. To recover the polymer after reaction, conventional procedures may be used such as discharging the system into water with subsequent filtration and washing with water or removal of solvent through flushing followed by water washing, etc. The polymerization and reaction as described above, may be effected in the presence of an alkaline metal salt

Claim 18

A method of preparing a stabilized polyphenylene sulfide according to any of the claims 1 to 5, which comprises preparing a polyphenylene sulfide consisting