Process for producing poly (arylene sulfide)

Details Process for producing poly (arylene sulfide) Process for producing poly (arylene sulfide)

1998-12-31

2001-03-13

Truong, Duc (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From sulfur-containing reactant

C528S374000, C528S375000, C528S487000, C528S491000, C528S492000, C528S499000, C528S501000, C528S503000

Reexamination Certificate

active

06201097

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to the field of processes for producing poly(arylene sulfide), hereinafter referred to as P(AS).
BACKGROUND OF THE INVENTION
The production of P(AS) for a variety of industrial and commercial uses has been known for some time. P(AS) is moldable into various articles including, but not limited to, parts, films, and fibers by means of, for example, injection molding and extrusion molding techniques. These articles have utility in a variety of applications where heat and chemical resistance properties are desired. For example, P(AS) can be utilized as a material for preparing electrical and electronic parts and automotive parts.
Generally, P(AS) is prepared by contacting reactants comprising a dihalogenated aromatic compound, a first polar organic compound, and a sulfur source under polymerization condition to produce a polymerization reaction mixture. In recovery of high molecular weight P(AS) product from the polymerization reaction mixture, a commercially unusable mixture remains. The high molecular weight P(AS) product is utilized for commercial purposes, as described above.
The recycle mixture comprises low molecular weight P(AS) and linear and cyclic P(AS) oligomers. The recycle mixture often is called “slime” due to its undesirable physical characteristics. Unfortunately, the recycle mixture, even though it comprises low molecular weight P(AS) and linear and cyclic P(AS) oligomers, has little or no commercial value. Thus, the recycle mixture often is disposed of in landfills or other disposal facilities.
There is a need in the P(AS) industry for a process to recover, recycle, and/or polymerize the recycle mixture to produce a high molecular weight P(AS).
SUMMARY OF THE INVENTION
It is an object of this invention to provide a more efficient process to produce P(AS) product.
It is another object of this invention to provide a process to utilize the recycle, commercially unusable, i.e., mixture to produce a commercially desirable second higher molecular weight P(AS) product.
In accordance with the present invention, a process is provided for producing a second high molecular weight P(AS) product, said process comprising the steps of:
1) removing a majority of a first high molecular weight poly(arylene sulfide) product from a polymerization reaction mixture and recovering a recycle mixture;
wherein said polymerization reaction mixture comprises said first high molecular weight poly(arylene sulfide) product, low molecular weight poly(arylene sulfide), cyclic and linear poly(arylene sulfide) oligomers, at least one first polar organic compound, at least one first promoter compound, an alkali metal by-product, reactants, and water; and
wherein said recycle mixture comprises:
(a) low molecular weight poly(arylene sulfide);
(b) cyclic poly(arylene sulfide) oligomers of the formula
where 4≦n≦30;
wherein R is selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, alkylaryl, and arylalkyl radicals having from about 6 to about 24 carbon atoms.
(c) linear poly(arylene sulfide) oligomers of the formula
where 1≦p≦50, and X and Y are independently selected from the group consisting of a hydrogen atom; a halogen atom; a phenoxy group; a halogenated phenyl group; a hydroxy group and the salts thereof; a cyclic amide; mercaptan groups and the salts thereof; substituted and unsubstituted amines of the formula
where R
1
and R
2
are selected from the group consisting of a hydrogen atom, an alkyl group having from 1 to 10 carbon atoms, a carboxylic acid having from 1 to 10 carbon atoms and a carboxylate having from 1 to 10 carbon atoms;
2) forming a two phase recycle mixture by a method selected from the group consisting of a) maintaining sufficient first polar organic compound and first promoter compound in said recycle mixture and b) adding sufficient second polar organic compound and second promoter compound to said recycle mixture;
3) heating said two phase recycle mixture to produce a recycle product reaction mixture;
4) recovering a second high molecular weight poly(arylene sulfide) product from said recycle product reaction mixture.
These objects and other objects of this invention will become more apparent with reference to the following.
DETAILED DESCRIPTION OF THE INVENTION
Different embodiments of this invention provide processes for producing a second high molecular weight poly(arylene sulfide) product. In a first embodiment of this invention, step 1 comprises removing a majority of a first high molecular weight P(AS) product from a polymerization mixture and recovering a recycle mixture. As used herein, the term “high molecular weight” or “high molecular weight P(AS)” means all P(AS) having molecular weights high enough to be commercially desirable and useable in an uncured state. Generally, the melt flow of a high molecular weight P(AS) usually is less than about 3,000 g/10 min., as disclosed in U.S. Pat. No. 5,334,701, herein incorporated by reference.
The polymerization reaction mixture comprises a first high molecular weight P(AS) product, low molecular weight P(AS), cyclic and linear P(AS) oligomers, at least one first polar organic compound, at least one first promoter compound, an alkali metal halide by-product, reactants, and water. As used herein, the term “low molecular weight” or “low molecular weight P(AS)” means all P(AS) having molecular weights low enough to be commercially undesirable and not useable in an uncured state. Generally, the melt flow of a low molecular weight P(AS) usually is greater than about 3,000 g/10 min., as disclosed in U.S. Pat. No. 5,334,701, previously incorporated by reference. Polymerization reaction mixtures useful in this invention can be produced by any method known to those of ordinary skill in the art. Examples of the polymerization reaction mixtures useful in this invention are those prepared according to U.S. Pat. Nos. 3,919,177, 3,354,129, 4,038,261, 4,038,262, 4,116,947, 4,282,347 and 4,350,810, all herein incorporated by reference.
Generally, polymerization reaction mixtures are prepared by contacting reactants comprising a dihalogenated aromatic compound, at least one first polar organic compound, at least one sulfur source, at least one base, and at least one first promoter compound under polymerization conditions.
Reaction mixtures that can be treated by the processes of this invention also include those in which components of the reaction mixture are premixed to form complexes before all of the components are brought together under polymerization conditions.
Dihalogenated aromatic compounds suitable for producing said polymerization reaction mixture can be represented by the formula
wherein X is a halogen, and R is selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, alkylaryl, and arylalkyl radicals having from about 6 to about 24 carbon atoms. Exemplary dihalogenated aromatic compounds include, but are not limited to, and are selected from the group consisting of p-dichlorobenzene, p-dibromobenzene, p-diiodobenzene, 1-chloro-4-bromobenzene, 1-chloro-4-iodobenzene, 1-bromo-4-iodobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1-ethyl-4-isopropyl-2,5-dibromobenzene, 1,2,4,5-tetramethyl-3,6-dichlorobenzene, 1-butyl-4-cyclohexyl-2,5-dibromobenzene, 1-hexyl-3-dodecyl-2,5-dichlorobenzene, 1-octadecyl-2,5-diiodobenzene, 1-phenyl-2-chloro-5-bromobenzene, 1-p-tolyl-2,5-dibromobenzene, 1-benzyl-2,5-dichlorobenzene, 1-octyl-5-(3-methylcyclopentyl)-2,5-dichlorobenzene, and mixtures thereof. The preferred dihalogenated aromatic compound for use in this invention is p-dichlorobenzene, hereinafter referred to as DCB, due to availability, ease of use, and high polymerization productivity.
At least one first polar organic compound is utilized to produce the polymerization mixture. First polar organic compounds include, but are not limited to, cyclic or acyclic organic amides having from about 1 to about 10 carbon atoms per molecule. Exemplary first polar organic compounds are selected from the group consisting of 1,3-dimethyl-2-imidazolidi

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