Halogenated wax grafted to low molecular weight polymer and rubber composition
A wax-polymer compound includes (a) a polymer component that is a polymerized unsaturated monomer, optionally copolymerized with a vinyl-aromatic monomer, and (b) a halogenated hydrocarbon wax component. The polymer component is grafted to the halogenated hydrocarbon wax component, and the wax-polymer compound has a number average molecular weight of about 1,000 to about 100,000, A method of making the wax-polymer compound and a coated silica particle are also disclosed. A rubber composition includes a rubber elastomer comprising a polymerized unsaturated monomer and optionally a polymerized vinyl-aromatic monomer, the elastomer having a number average molecular weight of about 100,000 to about 1,000,000. It further includes a filler in an amount of about 5 to about 200 phr, the filler comprising carbon black, silica, or both; and a wax-polymer additive.
1. A wax-polymer compound, comprising:
(a) a polymer component that is a polymerized unsaturated monomer, optionally copolymerized with a vinyl-aromatic monomer, and
(b) a halogenated hydrocarbon wax component;
the polymer component grafted to the halogenated hydrocarbon wax component, the compound having a number average molecular weight of about 1,000 to about 100,000.
2. The wax-polymer compound of claim 1 , wherein the halogenated hydrocarbon wax component is a chlorinated paraffin wax.
3. The wax-polymer compound of claim 1 , wherein the halogenated hydrocarbon wax component is a solid at 0° C.
4. The wax-polymer compound of claim 1 , wherein two or more polymer chains of the polymer component are bonded to a single halogenated hydrocarbon wax component.
5. The wax-polymer compound of claim 1 , wherein the polymer component is grafted to the halogenated hydrocarbon wax component at more than one graft location.
6. The wax-polymer compound of claim 1 , wherein the halogenated hydrocarbon wax component is halogenated along a hydrocarbon chain backbone of the wax.
7. The wax-polymer compound of claim 1 , wherein the wax-polymer compound has a ratio of the halogenated hydrocarbon wax component to the polymer component of about 1:1 to about 1:20.
8. The wax-polymer compound of claim 1 , wherein the unsaturated monomer is a diene monomer.
9. The wax-polymer compound of claim 1 , wherein the halogenated hydrocarbon wax component has a number average molecular weight of about 200 to about 5,000.
10. The wax-polymer compound of claim 1 , wherein the polymer component has a number average molecular weight of about 1,000 to about 20,000.
11. A method for making a wax-polymer compound comprising:
mixing:
(a) a polymer component that is living or functionalized and includes a polymerized unsaturated monomer, optionally copolymerized with a vinyl-aromatic monomer; and
(b) a halogenated hydrocarbon wax component;
and
maintaining the mixing until the wax-polymer compound is formed, the wax-polymer compound having a number average molecular weight of about 1,000 to about 100,000.
12. The method of claim 11 , wherein the halogenated wax component is dissolved in solution prior to the mixing.
13. The method of claim 11 , further comprising polymerizing the unsaturated monomer or copolymerizing the unsaturated monomer with the vinyl-aromatic monomer prior to the mixing.
14. The method of claim 11 , wherein the halogenated hydrocarbon wax component is mixed in a ratio with the polymer component in a range of about 1:1 to about 1:20.
15. The method of claim 11 , wherein the polymer component comprises two or more polymer chains that are bonded to a single halogenated hydrocarbon wax.
16. The method of claim 11 , wherein the polymer component is grafted to the halogenated hydrocarbon wax component at more than one graft location.
17. A rubber composition, comprising:
a rubber elastomer comprising a polymerized unsaturated monomer and optionally a polymerized vinyl-aromatic monomer, the elastomer having a number average molecular weight of about 100,000 to about 1,000,000;
a filler in an amount of about 5 to about 200 phr, the filler comprising carbon black, silica, or both; and
a wax-polymer additive that includes:
(a) a polymer component that is a polymerized unsaturated monomer, optionally copolymerized with a vinyl-aromatic monomer, and
(b) a halogenated hydrocarbon wax component;
the polymer component being grafted to the halogenated hydrocarbon wax component, the wax-polymer additive having a number average molecular weight of about 1,000 to about 100,000.
18. The rubber composition of claim 17 , wherein the wax-polymer additive has a ratio of the halogenated hydrocarbon wax component to the polymer component of about 1:1 to about 1:20.
19. The rubber composition of claim 17 , wherein the composition is essentially free of processing oil.
20. The rubber composition of claim 17 , wherein the composition comprises about 5 phr or less of processing oil and the filler is carbon black, wherein the composition has a Mooney viscosity (ML1+4, 103° C., RPA) of about 20 to about 60.