Coated high strength fibers
The invention relates to a high strength fibers comprising a coating of cross-linked silicone polymer, and ropes made thereof. The fibers are preferably high performance polyethylene (HPPE) fibers. The coating comprising a cross-linked silicone polymer is made from a coating composition comprising a cross-linkable silicone polymer. The rope shows markedly improved service life performance in bending applications such as cyclic bend-over-sheave applications. The invention also relates to the use of a cross-linked silicone polymer in a rope for an improvement of bend fatigue resistance.
1. A coated high strength fiber comprising a high performance polyethylene (HPPE) fiber, and a coating comprising a cross-linked silicone polymer on the fiber, wherein the cross-linked silicone polymer has a degree of cross-linking of at least 20%.
2. The coated high strength fiber according to claim 1 , wherein the degree of cross-linking of the cross-linked silicone polymer is at least 30%.
3. The coated high strength fiber according to claim 1 , wherein the HPPE fiber is made of ultrahigh molecular weight polyethylene (UHMWPE) having an intrinsic viscosity of at least 5 dl/g determined in decalin at 135° C.
4. The coated high strength fiber according to claim 1 , wherein the coating comprising the cross-linked silicone polymer is obtained by applying a coating composition comprising a cross-linkable silicone polymer onto the fiber; and cross-linking the cross-linkable silicone polymer.
5. The coated high strength fiber according to claim 4 , wherein the cross-linkable silicone polymer comprises a silicone polymer having a cross-linkable end-group.
6. The coated high strength fiber according to claim 5 , wherein the cross-linkable end-group is a vinyl group.
7. The coated high strength fiber according to claim 4 , wherein the cross-linkable silicone polymer has the formula:
CH 2 ═CH—(Si(CH s ) 2 O) n —CH═CH 2 (1)
wherein n is a number from 2 to 200.
8. The coated high strength fiber according to claim 4 , wherein the coating composition further comprises a cross-linker having the formula:
Si(CH 3 ) 3 O—(SiCH 3 HO) m —Si(CH 3 ) 3 (2)
wherein m is a number of 2 to 200.
9. The coated high strength fiber according to claim 4 , wherein the coating composition further comprises a platinum catalyst.
10. A rope comprising high performance polyethylene (HPPE) fibers, wherein the rope includes a coating comprising a cross-linked silicone polymer having a degree of cross-linking of at least 20%.
11. The rope according to claim 10 , wherein the degree of cross-linking of the cross-linked silicone polymer is at least 30%.
12. A fishing net which comprises a coated high strength fiber according to claim 1 .
13. A method of making coated high performance polyethylene (HPPE) fibers, comprising the steps of:
a) applying a coating composition comprising a cross-linkable silicone polymer to the HPPE fibers; and
b) cross-linking the silicone polymer to achieve a degree of cross-linking thereof of at least 20%.
14. The method according to claim 13 , wherein step b) is practiced to achieve a degree of cross-linking of at least 30%.
15. A method of making a rope comprising high performance polyethylene (HPPE) fibers, comprising the steps of:
a) applying a coating composition comprising a cross-linkable silicone polymer to the HPPE fibers;
b) cross-linking the silicone polymer to achieve a degree of cross-linking thereof of at least 20%; and
c) constructing a rope from the coated fibers obtained in step b).
16. The method according to claim 15 , wherein step b) is practiced to achieve a degree of cross-linking of 30%.
17. A strand comprising high performance polyethylene (HPPE) fibers, wherein the strand includes a coating comprising a cross-linked silicone polymer having a degree of cross-linking of at least 20%.
18. The strand according to claim 17 , wherein the degree of cross-linking of the cross-linked silicon polymer is at least 30%.