Process for the production of poly(vinyl acetate) and poly(vinyl alcohol)

Claim 2

A bulk polymerization process for producing poly(vinylacetate) which comprises polymerizing vinyl acetate essentially in the absence of ionizing radiation at a temperature in the range of from about 0° to about 40° C., and in the presence of from about 1×10 -6 to about 1×10 -3 mole percent of an initiator based on the total moles of vinyl acetate monomer, said initiator of the formula: R.sub.1 --N═N--R.sub.2 wherein: R 1 and R 2 are the same or different and are straight or branched chain lower alkyl, lower alkoxyalkyl, cycloalkyl, nitrile substituted alkyl, or phenylalkylnitrile, for a time sufficient to provide essentially linear poly(vinylacetate) having an average molecular weight of at least about 1.0×10 6 .

Claim 3

A process according to claim 1 wherein said process further comprises hydrolyzing said poly(vinyl acetate) to provide the corresponding poly(vinyl alcohol), which upon acetylation provides a poly(vinyl acetate) having an intrinsic viscosity of at least about 3.3 dL/g.

Claim 4

A process according to claim 1 wherein said process is carried out at a temperature of from about 10° C. to about 35° C.

Claim 5

A process according to claim 3 wherein said process is carried out at a temperature of from about 15° C. to about 30° C.

Claim 6

A process according to claim 1 wherein said effective initiator is an azo compound having a half life of up to about 200 h at a temperature of from about 0° C. to about 40° C.

Claim 7

A process according to claim 5 wherein said effective initiator is an azo compound having a half life of from about 1 h to about 200 h at a temperature of from about 0° C. at about 40° C.

Claim 8

A process according to claim 6 wherein said initiator is an azo compound having a half life of from about 10 to about 150 h at a temperature of from about 10° C. to about 35° C.

Claim 9

A process according to claim 7 wherein said initiator is an azo compound having a half life of from about 50 to about 100 hours at a temperature of from about 15° C. to about 30° C.

Claim 10

A process according to claim 1 wherein said initiator is 2,2-azobis-(2,4-dimethyl-4-methoxyvaleronitrile.

Claim 11

A process according to claim 1 wherein the concentration of said initiator is from about 1×10 -6 to about 1×10 -3 mole percent based on the total moles of vinyl acetate monomer.

Claim 12

A process according to claim 1 wherein said mole percent is from about 1×10 -5 to about 1×10 -3 .

Claim 13

A process according to claim 11 wherein said mole percent is from about 2×10 -5 to about 2×10 -4 .

Claim 14

A process according to claim 12 wherein said mole percent is from about 5×10 -5 to about 5×10 -4 .

Claim 15

A process according to claim 4 wherein said polymerization is carried out for a time period of from about 2 to about 48 hours.

Claim 16

A process according to claim 14 wherein said time period is from about 4 to about 36 hr.

Claim 17

A process according to claim 15 wherein said time period is from about 6 to about 24 hr.

Claim 18

A process according to claim 16 wherein said time period is from about 6 to about 18 hours.

Claim 19

A bulk polymerization process for producing high molecular weight poly(vinyl alcohol) which comprises the steps of: (a) polymerizing vinyl acetate monomer essentially in the absence of ionizing radiation at a temperature in the range of from about 0° C. to about 40° C. in the presence of from about 1×10 -6 to about 1×10 -3 mole percent of an initiator based on the total moles of vinyl acetate monomer, said initiator of the formula: R.sub.1 --N═N--R.sub.2 wherein: R 1 and R 2 are the same or different and are straight or branched chain lower alkyl, lower alkoxyalkyl, cycloalkyl, nitrite substituted alkyl or phenylalkyl, for a time sufficient to provide an essentially linear poly (vinyl acetate) having a weight average molecular weight of at least about 1.0×10 6 ; and (b) subjecting said poly(vinyl acetate) to alcoholysis or hydrolysis to provide the corresponding poly(vinyl alcohol) having a weight average molecular weight of at least about 0.4×10 6 .

Claim 20

A bulk polymerization process for producing high molecular weight poly(vinyl alcohol) which comprises the steps of: (a) polymerizing vinyl acetate monomer essentially in the absence of ionizing radiation at a temperature in the range of from about 0° C. to about 40° C. in the presence of from about 1×10 -6 to about 1×10 -3 mole percent of an initiator based on the total moles of vinyl acetate monomer, said initiator of the formula: R.sub.1 --N═N--R.sub.2 wherein: R 1 and R 2 are the same or different and are straight or branched chain lower alkyl, lower alkoxyalkyl, cycloalkyl, nitrite substituted alkyl or phenylalkyl, for a time sufficient to provide an essentially linear poly (vinyl acetate) having a weight average molecular weight of at least about 1.0×10 6 ; and (b) subjecting said poly(vinyl acetate) to alcoholysis or hydrolysis to provide the corresponding poly(vinyl alcohol) having a weight average molecular weight of at least about 0.4×10 6 .

Claim 21

A process according to claim 18 wherein the weight average molecular weight of said poly(vinyl acetate) is from about 1.3×10 6 to about 1.6×10 6 , and the weight average molecular weight of said corresponding poly(vinyl alcohol) is from about 0.5×10 6 to about 0.8×10 6 .