Polyesters having improved impact strength

Claim 2

An additive for blending with polyester or polyamide resins as an impact strength improver comprising an unsaturated backbone rubber formed by interpolymerization of ethylene, at least one mono-olefin containing 3 to 16 carbon atoms and polyene in which the backbone rubber has been grafted in a solvent medium in the presence of a free radical initiator with an ester having the structure: ##STR3## wherein R' is an organic group having an epoxide functionality, R" is alkyl and R is selected from the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl and aryl, said ester being present in an amount of 1 to 10 percent by weight of the rubber, said additive being substantially gel free.

Claim 3

A composition as claimed in claim 1, in which the mono-olefin monomer is propylene.

Claim 4

A composition as claimed in claim 1, in which the ethylene and propylene are present in the backbone rubber in the molar ratio of 70:30 to 45:55 ethylene:propylene.

Claim 5

A composition as claimed in claim 1, in which the polyene is a polyunsaturated bridged ring hydrocarbon or halogenated derivative thereof.

Claim 6

A composition as claimed in claim 1, in which the polyene is 5-ethylidene-2-norbornene.

Claim 7

A composition as claimed in claim 1, in which the polyene is bound in the rubber in an amount to provide 2-20 C═C groups per 1000 carbon atoms.

Claim 8

A composition as claimed in claim 1, in which the polyene is bound in the backbone rubber in an amount to provide 2-10 C═C groups per 1000 carbon atoms.

Claim 9

A composition as claimed in claim 1, in which the ester grafted onto the backbone rubber is glycidyl methacrylate.

Claim 10

A composition as claimed in claim 1, in which the level of graft is within the range of 1.5-4.0 percent by weight of the rubber.

Claim 11

An additive for blending with polyester as polyamide resins as an impact strength improver comprising an unsaturated backbone rubber formed by interpolymerization of ethylene, at least one mono-olefin containing 3 to 16 carbon atoms, and a polyene in which the backbone rubber has been grafted in a solvent medium in the presence of a free radical initiator with a graft monomer selected from the group consisting of (a) an alkylacrylate with epoxy functionality at the alkoxy position and (b) an acrylate with epoxy functionality at the alkoxy position used in combination with a cross-linking-inhibiting monomer in the form of methyl methacrylate, said cross-linking-inhibiting monomer being used in an amount sufficient to minimize cross-linking of the rubber, said additive being substantially gel free.

Claim 12

An additive for blending with polyester as polyamide resins as an impact strength improver comprising an unsaturated backbone rubber formed by interpolymerization of ethylene, at least one mono-olefin containing 3 to 16 carbon atoms, and a polyene in which the backbone rubber has been grafted in a solvent medium in the presence of a free radical initiator with a graft monomer selected from the group consisting of (a) an alkylacrylate with epoxy functionality at the alkoxy position and (b) an acrylate with epoxy functionality at the alkoxy position used in combination with a cross-linking-inhibiting monomer in the form of methyl methacrylate, said cross-linking-inhibiting monomer being used in an amount sufficient to minimize cross-linking of the rubber, said additive being substantially gel free.

Claim 13

A composition as claimed in claim 10 wherein the graft monomer is glycidyl methacrylate.

Claim 14

A composition as claimed in claim 10, wherein said graft monomer is one of those specified in paragraph (b).

Claim 15

An additive for blending with polyester, polycarbonate or polyamide resins as an impact strength improver comprising an unsaturated backbone rubber formed by interpolymerization of ethylene, at least one mono-olefin containing 3 to 16 carbon atoms and polyene in which the backbone rubber has been grafted in a solvent medium in the presence of a free radical initiator with an ester having the structure: ##STR4## where R' is an organic group having an epoxide functionality, R is selected from the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl and aryl, and R" is hydrogen, and also in the presence of a methyl methacrylate monomer to inhibit cross-linking of the ester with the unsaturated rubber, said additive being substantially gel free.

Claim 16

An additive for blending with polyester, polycarbonate or polyamide resins as an impact strength improver comprising an unsaturated backbone rubber formed by interpolymerization of ethylene, at least one mono-olefin containing 3 to 16 carbon atoms and polyene in which the backbone rubber has been grafted in a solvent medium in the presence of a free radical initiator with an ester having the structure: ##STR4## where R' is an organic group having an epoxide functionality, R is selected from the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl and aryl, and R" is hydrogen, and also in the presence of a methyl methacrylate monomer to inhibit cross-linking of the ester with the unsaturated rubber, said additive being substantially gel free.

Claim 17

An additive as claimed in claim 13, in which the ester is glycidyl acrylate.

Claim 18

An additive as claimed in claim 13, in which the polyene is a diene.

Claim 19

An additive as claimed in claim 15, in which the diene is 5-ethylidene-2-norborene.

Claim 20

An additive as claimed in claim 14, in which the unsaturated rubber is grafted with the ester to a level of graft of 1-10 percent by weight.