Moisture-curable melt-processible ethylene graft copolymers

DETAILED DESCRIPTION OF THE INVENTION In this disclosure, the word `copolymer` with no further qualification is meant to embrace polymers containing two or more than two monomers within it chains as well as grafted copolymers, where further monomers or other compounds are grafted on an existing polymer chain.
To distinguish the two type of copolymer the phrase `direct copolymer` is used to describe the former, and the phrase `graft-copolymer` for the latter.
The graft copolymers of this invention have graft units grafted on direct copolymer chains.
The term epoxide, or epoxide group refers to the group ##STR1## It is sometimes referred to as an epoxy group.
The term epoxide ring and oxirane ring is also used to describe the moiety.
The term glycidyl is used for the group derived from glycidol or 2,3-epoxy-1-propanol.
Thus a glycidyl monomer is an epoxy or epoxide group containing monomer, and a glycidyl group contains an epoxy or epoxide group.
The direct copolymer has within it units derived from a monomer containing an epoxide group, and more specifically a glycidyl group.
For convenience, and in accord with common usage, the copolymer is said to `contain` a glycidyl monomer.
The glycidyl monomers are the glycidyl esters of acrylic and methacrylic acid, and also glycidyl vinyl ether.
Glycidyl methacrylate is especially preferred.
Below 1 wt.
%, glycidyl monomer in the copolymer there are insufficient grafting sites to provide sufficient grafting on of the silane.
Above about 10 wt.
%, control of the grafting reaction, and stability of the resulting graft copolymer can suffer.
From 3-9 wt.
% of glycidyl monomer is preferred, most preferably from 6-8 wt.
%.
Higher levels of glycidyl monomer in the copolymer, particularly above about 6 wt.
% can provide more rapid grafting of the aminosilane, with lower amounts of grafting catalyst, or even without grafting catalyst at all.
When the copolymer contains lower levels of glycidyl monomer it is preferable to use grafting catalysts to speed up the grafting reaction with aminosilanes