Radiation cross-linking of polyamides

Claim 2

A heat-recoverable article composed of a radiation cross-linked polymeric composition which has an M 100 value above its melting point of at least 30 psi and which comprises (a) a cross-linked organic polymer component which comprises at least 80% by weight of at least one polyamide consisting essentially of monomer units which are linked to each other through amide linkages, at least 25% by weight of said monomer units having the formula --NH--(CH.sub.2).sub.p --CO-- where p is 11 or 12; and (b) the residue of an unsaturated radiation cross-linking agent used in the radiation cross-linking of said polymer component.

Claim 3

An article according to claim 1 wherein said organic polymer component consists essentially of at least one said polyamide.

Claim 4

An article according to claim 1 wherein at least 75% by weight of said monomer units have the formula --NH--(CH.sub.2).sub.p --CO-- where p is 11 or 12.

Claim 5

An article according to claim 1 wherein said polymer component consists essentially of (a) 25 to 100% by weight of a polymer selected from Nylon-11, Nylon-12, and blends of Nylon-11 and Nylon-12; and (b) 0 to 75% by weight of a polymer selected from Nylon-6, Nylon-6,6, Nylon 6,9, Nylon 6,10, and Nylon 6,12 and blends of two or more of these.

Claim 6

An article according to claim 4 wherein said organic polymer component consists essentially of 75 to 100% by weight of (a) and 0 to 25% by weight of (b).

Claim 7

An article according to claim 5 wherein said organic polymer component consists essentially of a polymer selected from Nylon-11, Nylon-12, and blends of Nylon-11 and Nylon-12.

Claim 8

An article according to claim 1 which is substantially uniformly cross-linked through the thickness thereof.

Claim 9

An article according to claim 1 wherein said cross-linking agent is selected from the group consisting of triallyl isocyanurate and triallyl cyanurate and mixtures thereof.

Claim 10

An article according to claim 5 which has an M 100 value above its melting point of 35 to 60 psi.

Claim 11

An article according to claim 5 which has an E 30 value above its melting point of 80 to 140 psi.

Claim 12

An article according to claim 10 which contains less than 2% by weight of residues of said cross-linking agent, based on the weight of the organic polymer component.

Claim 13

An article according to claim 1 which is hollow and heat-shrinkable and which has an inner surface which has a coating on at least a part thereof of a material which flows at the recovery temperature of the article.

Claim 14

An article according to claim 1 wherein said composition further comprises 15 to 35% by weight of a halogenated organic flame retardant and 5 to 15% by weight of an inorganic synergist therefor.

Claim 15

A heat-shrinkable tube composed of a radiation cross-linked polymeric composition which comprises (a) an organic polymer component which consists essentially of cross-linked Nylon-11 and (b) the residue of an unsaturated radiation cross-linking agent, said tube having an M 100 value at 200° C. of 35 to 60 psi.

Claim 16

A heat-shrinkable tube composed of a radiation cross-linked polymeric composition which comprises (a) an organic polymer component which consists essentially of cross-linked Nylon-11 and (b) the residue of an unsaturated radiation cross-linking agent, said tube having an M 100 value at 200° C. of 35 to 60 psi.

Claim 17

A tube according to claim 14 which has on its inner surface a coating of a material which flows at the recovery temperature of the article.

Claim 18

A tube according to claim 14 wherein said coating is composed of Nylon-12.

Claim 19

An article according to claim 14 which is substantially uniformly cross-linked through the thickness thereof.

Claim 20

A process for the manufacture of a cross-linked polymeric article which comprises the steps of (1) melt-shaping a polymeric composition comprising (a) an organic polymer component which comprises at least 90% by weight of at least one polyamide consisting essentially of monomer units which are linked to each other through amide linkages, at least 25% by weight of said monomer units having the formula --NH--(CH.sub.2).sub.p --CO-- where p is 11 or 12; and (b) an unsaturated radiation cross-linking agent for said polymer; and (2) irradiating the shaped article prepared in step (1) to effect cross-linking thereof to a level such that the article has an M 100 value above its melting point of at least 30 psi.

Claim 21

A process for the manufacture of a cross-linked polymeric article which comprises the steps of (1) melt-shaping a polymeric composition comprising (a) an organic polymer component which comprises at least 90% by weight of at least one polyamide consisting essentially of monomer units which are linked to each other through amide linkages, at least 25% by weight of said monomer units having the formula --NH--(CH.sub.2).sub.p --CO-- where p is 11 or 12; and (b) an unsaturated radiation cross-linking agent for said polymer; and (2) irradiating the shaped article prepared in step (1) to effect cross-linking thereof to a level such that the article has an M 100 value above its melting point of at least 30 psi.

Claim 22

A process according to claim 18 wherein said organic polymer component consists essentially of at least one said polyamide.

Claim 23

A process according to claim 18 wherein at least 75% by weight of said monomer units have the formula --NH--(CH.sub.2).sub.p --CO-- where p is 11 or 12.

Claim 24

A process according to claim 18 wherein said polymer component consists essentially of (a) 25 to 100% by weight of a polymer selected from Nylon-11, Nylon-12, and blends of Nylon-11 and Nylon-12; and (b) 0 to 75% by weight of a polymer selected from Nylon-6, Nylon-6,6, Nylon 6,9, Nylon 6,10, and Nylon 6,12 and blends of two or more of these.

Claim 25

A process according to claim 21 wherein said organic polymer component consists essentially of 75 to 100% by weight of (a) and 0 to 25% by weight of (b).

Claim 26

A process according to claim 22 wherein said organic polymer component consists essentially of a polymer selected from Nylon-11, Nylon-12, and blends of Nylon-11 and Nylon-12.

Claim 27

A process according to claim 18 wherein said cross linking agent is selected from the group consisting of triallyl isocyanurate and triallyl cyanurate and mixtures thereof.

Claim 28

A process according to claim 18 wherein the amount of said cross-linking agent is less than 4% by weight, based on the weight of the organic polymer component, and the shaped article is irradiated to a dose of at most 12 Mrad.

Claim 29

A process according to claim 25 wherein the shaped article is irradiated in air to a dose of at most 8 Mrad.

Claim 30

A process according to claim 25 wherein the cross-linked article has an M 100 value above its melting point of 30 to 150 psi.

Claim 31

A process according to claim 18 wherein said composition further comprises 15 to 35% by weight of a halogenated organic flame retardant and 5 to 15% by weight of an inorganic synergist therefor.

Claim 32

A process according to claim 18 wherein the amount of said cross-linking agent is less than 2% by weight, based on the weight of the organic polymer component, and the shaped article is irradiated in air to a dose such that the cross-linked article has an M 100 value above its melting point of 35 to 60 psi.

Claim 33

A process according to claim 29 wherein said cross-linking agent is triallyl isocyanurate.

Claim 34

A process according to claim 18 which further comprises the steps of (3) heating the cross-linked article above its melting point; (4) deforming the article while it is at a temperature above its melting point; and (5) cooling the article while it is in the deformed condition; whereby a heat-recoverable article is prepared.