Thermoplastic elastomer compositions comprising ultrahigh molecular weight polyethylene and methods for making the same
Described herein are thermoplastic elastomer compositions that comprise 30-60 wt % of a thermoplastic vulcanizate, 5 to 25 wt % of a thermoplastic resin, 5 to 25 wt % of a high density polyethylene, and 5 to 40 wt % of a ultrahigh molecular weight polyethylene. The thermoplastic elastomer compositions may be particularly useful in forming laminates, such as slip coat laminates for glass run channels.
1. A thermoplastic elastomer composition comprising:
(a) 30 to 60 wt %, based on the weight of the composition, of a thermoplastic vulcanizate, wherein the thermoplastic vulcanizate comprises a rubber phase that is dispersed and at least partially cross-linked within a continuous thermoplastic resin component;
(b) 5 to 25 wt %, based on the weight of the composition, of thermoplastic resin;
(c) 5 to 25 wt %, based on the weight of the composition, of a high density polyethylene having a density of greater than 0.93 g/cc, wherein the high density polyethylene has a melt index of less than 2 g/10 min at 190° C. and 2.16 kg; and
(d) 5 to 40 wt %, based on the weight of the composition, of an ultrahigh molecular weight polyethylene, wherein the ultrahigh molecular weight polyethylene has an average particle size of less than 75 μm, and wherein the ultrahigh molecular weight polyethylene has a weight average molecular weight of greater than 1,500,000 g/mol;
wherein the thermoplastic elastomer composition has a surface roughness of from 3 to 6 μm, wherein the thermoplastic elastomer composition has a kinetic coefficient of friction at dry conditions of less than 0.5 according to ASTM D1894-99 on glass, and wherein the thermoplastic elastomer composition is essentially free of silicone oil.
2. The thermoplastic elastomer composition of claim 1 , wherein the composition comprises 40 to 50 wt % of the thermoplastic vulcanizate, based on the weight of the composition.
3. The thermoplastic elastomer composition of claim 1 , wherein the thermoplastic vulcanizate comprises 20 to 60 wt % of continuous thermoplastic resin component, 10 to 40 wt % of rubber, and 15 to 50 wt % of oil.
4. The thermoplastic elastomer composition of claim 1 , wherein the composition comprises 5 to 20 wt % of the high density polyethylene, based on the weight of the composition.
5. The thermoplastic elastomer composition of claim 1 , wherein the high density polyethylene has a density greater than 0.94 g/cc.
6. The thermoplastic elastomer composition of claim 1 , wherein the composition comprises 5 to 30 wt % of the ultrahigh molecular weight polyethylene, based on the weight of the composition.
7. The thermoplastic elastomer composition of claim 1 , wherein the composition comprises 7 to 15 wt % of the ultrahigh molecular weight polyethylene, based on the weight of the composition.
8. The thermoplastic elastomer composition of claim 1 , wherein the ultrahigh molecular weight polyethylene has an average particle size of from 20 to 75 μm.
9. The thermoplastic elastomer composition of claim 1 , wherein the ultrahigh molecular weight polyethylene has an average particle size of from 20 to 40 μm.
10. The thermoplastic elastomer composition of claim 1 , wherein the ultrahigh molecular weight polyethylene has a density greater than 0.91 g/cc.
11. The thermoplastic elastomer composition of claim 1 , wherein the ultrahigh molecular weight polyethylene has a weight average molecular weight of greater than 1,750,000 g/mol.
12. The thermoplastic elastomer composition of claim 1 , where the composition has an ultimate elongation of greater than 100%.
13. A laminate comprising:
(a) a first layer comprising a thermoplastic vulcanizate; and
(b) a second layer comprising the thermoplastic elastomer composition of claim 1 .
14. The laminate of claim 13 , wherein the laminate has an extrusion surface roughness of greater than 100 Ra.