Process for production of high to ultra-high molecular weight linear polyarylenesulfides
AssigneeKureha Kagaku Kogyo Kabushiki Kaisha
InventorsYo Iizuka, Takao Iwasaki, Takayuki Katto, Zenya Shiiki
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Abstract
By maintaining an arylenesulfide prepolymer with a melt viscosity of 5 to 3,000 poise at a temperature of 245.degree. to 290.degree. C. under a liquid-liquid two-phase separated state in a solvent for 1 to 50 hours, the molecular weight of said prepolymer is increased to a high to ultra-high value while the linearity of the polymer is retained.
Claims17
A process for producing a high molecular to ultra-high molecular weight linear polyarylenesulfide, which comprises:
- providing a prepolymer which is an arylenesulfide polymer having a melt viscosity of 5 to 3,000 poise measured at 310.degree. C. and a shear rate of 200 sec.sup.-1 ;
- placing the prepolymer in a solvent which consists essentially of a strongly alkaline mixture of an organic amide and 7 to 30% by weight of water;
- heating said prepolymer in said solvent at a temperature of from 245.degree. to 290.degree. C., whereby a mass is formed in a liquid-liquid two phase state wherein the prepolymer is present mostly in one of the two phases;
- maintaining the liquid-liquid two-phase state for 1 to 50 hours thereby to convert the prepolymer into an arylenesulfide polymer of a higher molecular weight;
- and
- recovering the arylenesulfide polymer of a higher molecular weight,
- the alkalinity of said strongly alkaline mixture being such that when diluted 10-fold with water, the pH thereof is 9.5 to 14.
A process for producing a high molecular weight to ultra-high molecular weight linear polyarylenesulfide, which comprises:
- heating an alkali metal sulfide and a dihalo-armoatic compound in an organic amide containing 0.5 to 2.4 moles of water per mole of the alkali metal sulfide charged, at a temperature of from 180.degree. C. to 240.degree. C., until an arylenesulfide polymer having a melt viscosity of 5 to 300 poise determined at 310.degree. C. and a shear rate of 200 sec.sup.-1 is formed with a conversion of the dihalo-aromatic compound of 70 to 98 mole % thereby form a prepolymer in a reaction mixture;
- adding additional water to the reaction mixture thus formed in a quantity of 2.5 to 7.0 moles per mole of the alkali metal sulfide charged;
- and
- heating the reaction mixture thus formed at a temperature of from 245.degree. C. to 290.degree. C. under strongly alkaline conditions, whereby a mass is formed in a liquid-liquid two phase state wherein the prepolymer is present mostly in one of the two phases;
- maintaining the liquid-liquid two-phase state for 1 to 50 hours thereby to convert the prepolymer into an arylenesulfide polymer of a higher molecular weight;
- and
- recovering the arylenesulfide polymer of a higher molecular weight,
- said strongly alkaline conditions being such that the pH of the reaction mixture when diluted 10-fold, is from 9.5-14.
A high molecular weight linear polyphenylenesulfide which has a melt viscosity of at least 7,000 measured at a temperature of 310.degree. C. under a shear rate of 200 sec.sup.-1 and is substantially free of a cross-linked structure.
Dependencies are inferred from the claim text.