Method of producing olefin polymer graft copolymers
AssigneeHimont Incorporated
InventorsAnthony J. DeNicola, Jr., Suhas Guhaniyogi
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Abstract
Disclosed is a method of making graft copolymers of olefin polymers by contacting a particulate olefin polymer with a free radical polymeriztion initiator, e.g., a peroxide, and a vinyl monomer at about from 60.degree. to 125.degree. C., while controlling the monomer addition rate so that it does not exceed about 4.5 pph/min, and most preferably does not exceed about 3.0 pph/min, at any monomer feed level. To prevent polymer degradation, a non-oxidizing environment is maintained throughout the process, and residual free radicals are deactivated, and unreacted initiator is decomposed, before the graft copolymer is exposed to air.
Claims21
A method of making a polyolefin graft copolymer comprising, in a substantially non-oxidizing environment,
- (a) treating a particulate olefin polymer material at a temperature of about from 60.degree. to 125.degree. C. with about from 0.1 to 6.0 pph of an organic compound which is a chemical free radical polymerization initiator and has a decomposition half-life at the temperature used of about from 1 to 240 minutes;
- (b) treating said olefin polymer material at said temperature over a time period which coincides with or follows (a), with or without overlap, with about from 5 to 240 pph of at least one grafting monomer capable of being polymerized by free radicals, said monomer being added to said olefin polymer material over a time period from 5 minutes to 3-4 hours to provide a rate of addition which is less than about 4.5 pph per minute at any addition level;
- and thereafter
- (c) removing any unreacted grafting monomer from the resultant grafted particulate olefin polymer material, and decomposing any unreacted initiator and deactivating any residual free radicals in said material.
The method of claim I wherein in (c) said grafted olefin polymer material is maintained at a temperature of at least about 110.degree. C. for at least about 5 minutes.
Dependencies are inferred from the claim text.