Adhesion technique for incompatible polymers using modified polymer tie layers
View Patent ↗A coextrusion employing a tie layer between two layers of different polymer materials. The tie layer is formed in the extrusion melt of a composition comprising one of the two polymer materials and a coupling agent that includes functional groups that are reactive at least with functional groups on the second polymer. The coupling agent may be incorporated into the tie layer material in amounts above 5% by weight.
1. An article comprising a laminate having first and second layers and a tie-layer therebetween bonding the first and second layers, the first and second layers formed, respectively, of first and second polymer materials, the first and second polymer materials being different, wherein
the first and second polymer materials, respectively, have first and second functional groups thereon, and
the tie layer is formed of a tie-layer polymer material obtained by melt modification of one of the first or the second polymer materials, said melt modification comprising incorporation therein of at least 5% by weight of a coupling agent, the coupling agent having functional groups thereon, at least some of which are reactive in the melt with at least the functional groups on the other of said first and second polymer materials, said coupling agent being selected from the group consisting of compounds having plural epoxy groups thereon, compounds having plural oxazaline groups thereon, compounds having plural carbodiimide groups thereon and compounds having plural isocyanate groups thereon.
2. An article as in claim 1 wherein the coupling agent functional groups further comprise functional groups which are reactive in the melt with the functional groups of said one of the first and second polymer materials.
3. An article as in claim 1 wherein the tie layer polymer has been crosslinked after formation of the laminate.
4. An article as in claim 1 wherein the first polymer material is a polyester or a polyamide, the second polymer material is a polyolefin and the tie layer material is obtained by modifying the second polymer material.
5. An article as in claim 1 wherein the coupling agent is incorporated into the tie layer material in an amount of from about 7% to about 35% by weight.
6. An article as in claim 1 wherein the coupling agent is incorporated into the tie layer material in an amount of 10-20% by weight.
7. Coextruded medical device tubing comprising a laminate having first and second layers and a tie-layer therebetween bonding the first and second layers, the first and second layers formed, respectively, of first and second polymer materials, the first and second polymer materials being different, wherein the first and second polymer materials, respectively, have first and second functional groups thereon, the tie layer is formed of a tie-layer polymer material obtained by melt modification of one the first or the second polymer materials, said melt modification comprising incorporation therein of at least 5% by weight of a coupling agent, the coupling agent having functional groups thereon, at least some of which are reactive in the melt with at least the functional groups on the other of said first and second polymer materials, and wherein
a) the coupling agent is a member of the group consisting of compounds having plural epoxy groups thereon, compounds having plural oxazaline groups thereon, compounds having plural carbodiimide groups thereon and compounds having plural isocyanate groups thereon, and/or
b) the tie layer material further comprises a catalyst for reaction of the coupling agent with functional groups on said other of said first and second polymer materials.
8. Coextruded medical device tubing as in claim 7 wherein the coupling agent functional groups further comprise functional groups which are reactive in the melt with the functional groups of said one of the first and second polymer materials.
9. Coextruded medical device tubing as in claim 7 wherein the tie layer polymer has been irradiatively crosslinked.
10. Coextruded medical device tubing as in claim 7 wherein the first polymer material is a polyester.
11. Coextruded medical device tubing as in claim 7 where the second polymer material is a polyolefin or a polyamide.
12. Coextruded medical device tubing as in claim 11 wherein the tie layer polymer material is a modified polyolefin or polyamide.
13. Coextruded medical device tubing as in claim 11 wherein the first polymer material is a polyester or a polyamide, the second polymer material is a polyolefin and the tie layer material is obtained by modifying the second polymer material.
14. Coextruded medical device tubing as in claim 13 wherein at least a portion of the second polymer material and the tie-layer polymer material have been crosslinked after formation of the laminate.
15. Coextruded medical device tubing as in claim 7 wherein the coupling agent is incorporated into the tie layer material in an amount of from 7% to about 35% by weight.
16. Coextruded medical device tubing as in claim 15 wherein the coupling agent is incorporated into the tie layer material in an amount of 10-20% by weight.
17. Coextruded medical device tubing as claim 7 wherein the tie layer includes said catalyst and the catalyst is selected from the group consisting of tri-valent phosphorous compounds, pentavalent phosphoric compounds, tin compounds, titanate compounds, tertiary amines, blocked amines, and mixtures thereof.