Silicone Wax Modified Low Wear Polyoxymethylene
A tribologically modified polyoxymethylene polymer composition is comprised of a polyoxymethylene polymer and at least one tribological modifier. The tribological modifier may comprise at least one silicone wax having a molecular weight of less than 40,000 g/mol. The composition may exhibit a dynamic coefficient of friction against a counter-material of from about 0.1 to about 0.5. The composition provides polymer articles with improved tribological properties.
1 . A polyoxymethylene polymer composition comprising
a polyoxymethylene copolymer, and
at least one silicone wax having a molecular weight of less than 40,000 g/mol.
2 . The polymer composition of claim 1 , wherein the silicone wax comprises a modified silicone wax.
3 . The polymer composition of claim 1 , wherein the silicone wax has a molecular weight of less than about 30,000 g/mol.
4 . The polymer composition of claim 1 , wherein the silicone wax comprises a modified polydimethylsiloxane wax.
5 . The polymer composition of claim 1 , wherein the silicone wax comprises an alkyl group having more than 2 carbon atoms, an amine group, a polyether group, a hydroxyl group, or any combination thereof.
6 . The polymer composition of claim 5 , wherein the silicone wax is comprised of pendant groups and wherein from about 10% to about 90% of the pendant groups are comprised of the alkyl group having more than 2 carbon atoms.
7 . The polymer composition of claim 5 , wherein the silicone wax comprises a polyether group and wherein the polyether group comprises from 2 to 5 carbon atoms.
8 . The polymer composition of claim 5 , wherein the silicone wax comprises a hydroxyl group and wherein the hydroxyl group has a hydroxyl value of from 5 to 150.
9 . The polymer composition of claim 1 , wherein the silicone wax is present in an amount of from about 0.1 wt. % to about 10 wt. %.
10 . The polymer composition of claim 1 , wherein the composition further comprises a nucleating agent in an amount of from about 0.05 wt. % to about 0.5 wt. %.
11 . The polymer composition of claim 10 , wherein the nucleating agent is a polyoxymethylene terpolymer.
12 . The polymer composition of claim 1 , wherein the composition further comprises an antioxidant in an amount of from about 0.05 wt % to about 0.5 wt. %.
13 . The polymer composition of claim 1 , wherein the composition further comprises a formaldehyde scavenger in an amount of from about 0.005 wt. % to about 0.1 wt. %.
14 . The polymer composition of claim 1 , wherein the composition further comprises an acid scavenger in an amount of from about 0.005 wt. % to about 0.1 wt. %.
15 . The polymer composition of claim 1 , wherein the composition further comprises a lubricant in an amount of from about 0.05 wt. % to about 0.5 wt. %.
16 . The polymer composition of claim 1 , wherein the composition has a dynamic coefficient of friction against a polyacetal surface of from about 0.1 to about 0.5.
17 . A polymer article comprising the composition of claim 1 .
18 . A polymer article comprising a polyoxymethylene polymer composition comprising:
a polyoxymethylene copolymer,
at least one silicone wax having a molecular weight of less than 40,000 g/mol, and
at least one of an antioxidant, a formaldehyde scavenger, a nucleating agent, an acid scavenger, a lubricant, or any combination thereof.
19 . The polymer article of claim 18 , wherein the silicone wax comprises a polydimethylsiloxane wax.
20 . The polymer article of claim 18 , wherein the silicone wax has a molecular weight of less than about 30,000 g/mol.
21 . The polymer article of claim 18 , wherein the silicone wax comprises an alkyl group having more than 2 carbon atoms, an amine group, a polyether group, a hydroxyl group, or any combination thereof.
22 . The polymer article of claim 21 , wherein the silicone wax is comprised of pendant groups and wherein from about 10% to about 90% of the pendant groups are comprised of the alkyl group having more than 2 carbon atoms.
23 . The polymer article of claim 21 , wherein the silicone wax comprises a polyether group and wherein the polyether group comprises from 2 to 5 carbon atoms.
24 . The polymer article of claim 21 , wherein the silicone wax comprises a hydroxyl group and wherein the hydroxyl group has a hydroxyl value of from 5 to 150.
25 . The polymer article of claim 18 , wherein the composition comprises a polyoxymethylene terpolymer in an amount of from about 0.05 wt. % to about 0.5 wt. %.
26 . The polymer article of claim 18 , wherein the composition comprises an antioxidant in an amount of from about in an amount of from about 0.05 wt % to about 0.5 wt. %, a formaldehyde scavenger in an amount of from about 0.005 wt. % to about 0.1 wt. %, an acid scavenger in an amount of from about 0.005 wt. % to about 0.1 wt. %, a lubricant in an amount of from about 0.05 wt. % to about 0.5 wt. %, or any combination thereof.
27 . The polymer article of claim 18 , wherein the article exhibits a dynamic coefficient of friction against a polyacetal surface of from about 0.1 to about 0.5.