Polymer epoxidation process

Claim 2

A process for the production of epoxidized polymers substantially free of gel which comprises contacting: (a) a rubbery polymer of a conjugated diene in (b) an aliphatic or alicyclic hydrocarbon diluent capable of dissolving said rubbery polymer with (c) hydrogen peroxide and (d) a mixture of formic acid and at least one other low molecular weight monocarboxylic acid under epoxidation conditions which produce substantially gel-free epoxidized rubbery polymers of conjugated diene.

Claim 3

A process according to claim 1 wherein the ratio (molar) of formic acid to said other acid ranges from about 3:2 to about 1:10 and said other acid has from 2 to 9, inclusive, carbon atoms per molecule.

Claim 4

A process according to claim 1 wherein said diluent has a boiling point in the range of about 35° to about 150° C., the amount of hydrogen peroxide ranges from about 1 to about 2 moles per mole of olefinic unsaturation in the polymer to be epoxidized, and the temperature during epoxidation is in the range of about -10° C. to about 120° C.

Claim 5

A process according to claim 1 wherein said rubbery polymer is selected from homopolymers of conjugated dienes having from 4 to 12, inclusive, carbon atoms and copolymers of said conjugated dienes and monovinylarenes having from 8 to 20, inclusive, carbon atoms, and wherein said polymers have a number average molecular weight in the range of about 5,000 to about 400,000.

Claim 6

A process according to claim 1 wherein (a) is a rubbery polymer selected from homopolymers of conjugated dienes having from 4 to 12 carbon atoms and copolymers of said conjugated dienes and monovinylarenes having from 8 to 20 carbon atoms, (b) is a hydrocarbon diluent having a boiling point ranging from about 35° C. to about 150° C., (c) the amount of hydrogen peroxide present ranges from about 1 to about 2 moles per mole of olefinic unsaturation in the polymer to be epoxidized, (d) the molar ratio of formic acid to said other acid ranges from about 3:2 to about 1:10, and further wherein the temperature of said contacting is in the range of about -10° C. to about 120° C.

Claim 7

A process according to claim 1 wherein (a) is a styrene-butadiene-styrene (20-60-20) block copolymer, (b) is cyclohexane, and (d) is a mixture of formic acid and acetic acid.

Claim 8

A process according to claim 1 wherein (a) is a linear styrene-butadiene tapered teleblock copolymer, (b) is cyclohexane, and (d) is a mixture of formic acid and acetic acid.

Claim 9

A process according to claim 1 wherein (a) is a linear styrene-butadiene tapered teleblock copolymer, (b) is cyclohexane, and (d) is a mixture of formic acid and propionic acid.

Claim 10

A process according to claim 1 wherein (a) is a divinylbenzene coupled butadiene-styrene (60-70/40-30) teleblock copolymer, (b) is cyclohexane, and (d) is a mixture of formic and acetic acids.