Compositions and methods for making them
Provided are compositions comprising: (i) a dispersed phase of rubber that is at least partially cured; (ii) a continuous thermoplastic phase including at least one thermoplastic polymer; (iii) a first polysiloxane having a number average molecular weight greater than 100 kg/mole; and (iv) a second polysiloxane having a number average molecular weight less than 100 kg/mole, and methods for making such compositions. Also provided are laminates including such compositions, weatherseals made therefrom, and methods for making them.
1. A composition consisting of:
(i) a dispersed phase of olefinic elastomeric copolymer rubber that is at least partially cured;
(ii) a continuous thermoplastic phase including at least one thermoplastic polymer, wherein the thermoplastic polymer comprises a polypropylene having a melt flow rate, as determine at 230° C., 2.16 kg, of greater than 3 g/10 min;
(iii) a first polysiloxane having a number average molecular weight greater than 100 kg/mole;
(iv) a second polysiloxane having a number average molecular weight less than 100 kg/mole;
(v) optionally, one or more slip aids;
(vi) optionally, one or more fillers;
(vii) optionally, one or more extender oils, synthetic processing oils or combinations thereof;
(viii) optionally one or more polymeric processing additives;
(ix) optionally, one or more stability-enhancing agents selected from the group consisting of antioxidants, UV stabilizers, antiozonants, biostats, and combinations thereof.
2. The composition of claim 1 , wherein the first polysiloxane has a molecular weight greater than 130 kg/mole.
3. The composition of claim 1 , wherein the second polysiloxane is a liquid polysiloxane.
4. The composition of claim 1 , wherein the first polysiloxane has an intrinsic viscosity, as determined per ASTM D1601 and D 4020, of greater than 10,000 dl/g.
5. The composition of claim 1 , wherein the second polysiloxane has an intrinsic viscosity, as determined per ASTM D1601 and D 4020, of less than 10,000 dl/g.
6. The composition of claim 1 , wherein the second polysiloxane has a viscosity of about 1,000 cSt or less.
7. The composition of claim 1 , wherein the composition comprises from about 8 to about 20 wt % of the first polysiloxane, based on the weight of the composition.
8. The composition of claim 1 , wherein the composition comprises from about 2 to about 12 wt % of the second polysiloxane, based on the weight of the composition.
9. The composition of claim 1 , wherein the composition comprises from about 4 to about 20 wt % of the rubber, based on the weight of the composition.
10. The composition of claim 1 , wherein the composition comprises from about 3 to about 85 wt % of the thermoplastic polymer, based on the weight of the composition.
11. The composition of claim 1 , wherein the one or more slip aids comprises a fatty acid amide.
12. The composition of claim 1 , wherein the composition comprises from about 0.5 to about 5 wt % of the slip aid, based on the weight of the composition.
13. The composition of claim 1 , wherein the polypropylene is crystalline polypropylene.
14. The composition of claim 1 , wherein the composition comprises from 20 to 60 wt % polypropylene, based on the weight of the composition.