Polyoxymethylene Polymer With Long Chain Alkylene Glycol End Groups
A polyoxymethylene polymer is disclosed that contains long-chain alkylene glycol end groups. The polyoxymethylene polymer may be formed by using a Bis-oligo-alkylene glycol-formal as a chain transfer agent during production of the polymer. The end groups on the polyoxymethylene polymer may comprise ethylene oxide end groups and/or propylene oxide end groups. The resulting polymer has excellent flow characteristics and may be used as a flow additive for other thermoplastic polymers. Alternatively, the polymer may be used to form various molded articles with excellent tribological properties.
1 . A thermoplastic polymer comprising:
a polyoxymethylene polymer with alkylene oxide end groups, the alkylene oxide end groups having an average molecular weight of from about 350 g/mol to about 10,000 g/mol.
2 . A thermoplastic polymer as defined in claim 1 wherein the polymer comprises a reaction product of a polyoxymethylene polymer or oligomer with a formal, the formal having the following chemical structure:
where R is H, or a linear or branched alkyl group; and
where n is from about 10 to about 150.
3 . A thermoplastic polymer as defined in claim 2 wherein n is from 12 to 60.
4 . A thermoplastic polymer as defined in claim 1 , wherein the polymer has the following formula:
where R is H, or a linear or branched alkyl group; and
where n is from about 10 to about 150; and POM is an oxymethylene homopolymer or copolymer.
5 . A thermoplastic polymer as defined in claim 2 , where R is an alkyl group having a carbon chain length of less than about 10 carbon atoms.
6 . A thermoplastic polymer as defined in claim 5 , wherein R is an ethyl or methyl group.
7 . A polymer composition comprising:
a thermoplastic polymer combined with a flow additive, the flow additive comprising a polyoxymethylene polymer with alkylene oxide end groups, the alkylene oxide end groups having an average molecular weight of from about 350 g/mol to about 10,000 g/mol.
8 . A polymer composition as defined in claim 7 , wherein the alkylene oxide end groups have an average molecular weight of from about 500 g/mol to about 5000 g/mol.
9 . A polymer composition as defined in claim 7 , wherein the thermoplastic polymer comprises a second polyoxymethylene polymer, the second polyoxymethylene polymer not including the alkylene oxide end groups.
10 . A polymer composition as defined in claim 7 , wherein the flow additive has the following formula:
where R is H, or a linear or branched alkyl group; and
where n is from about 10 to about 150; and POM is an oxymethylene homopolymer or copolymer.
11 . A polymer composition as defined in claim 7 , wherein the alkylene oxide end groups comprise monoalkylated alkylene oxide end groups.
12 . A polymer composition as defined in claim 7 , wherein the alkylene oxide end groups comprise monomethylated alkylene oxide end groups.
13 . A polymer composition as defined in claim 7 , where the flow additive comprises the reaction product of a polyoxymethylene polymer and a Bis-monomethylated polyalkylene glycol-formal.
14 . A polymer composition as defined in claim 13 , wherein the Bis-polyalkylene glycol-formal has the following structure:
where R is H, or a linear or branched alkyl group; and
where n is from 10 to 150.
15 . A polymer composition as defined in claim 7 , wherein the alkylene oxide end groups are attached to the polyoxymethylene polymer via an ether linkage.
16 . An article molded from the polymer composition defined in claim 7 .
17 . A polymer composition as defined in claim 7 , where in the flow additive has a melt-flow index of greater than about 5 grams/10 minutes.
18 . A process for producing a Bis-polyalkylene glycol-formal comprising:
combining a polyalkylene glycol with a formaldehyde source to form a reaction mixture;
contacting the reaction mixture with a catalyst in order to form a Bis-polyalkylene glycol-formal.
19 . A process as defined in claim 18 , wherein the polyalkylene glycol and the formaldehyde source are dissolved in a solvent.
20 . A process as defined in claim 19 , wherein the solvent comprises toluene.
21 . A process as defined in claim 18 , wherein the catalyst comprises a heterogeneous catalyst.
22 . A process as defined in claim 18 , where in the catalyst comprises an ion exchange resin.
23 . A process as defined in claim 19 , wherein the solvent forms an azeotrope with water and has a boiling point of less than about 150° C. at atmospheric pressure.
24 . A process as defined in claim 18 , wherein the polyalkylene glycol comprises an alkylated polyalkylene glycol and has a molecular weight of from about 350 to about 10,000.
25 . A process as defined in claim 18 , wherein the polyalkylene glycol comprises a monomethylated polyethylene glycol.
26 . A process as defined in claim 18 , wherein the Bis-polyalkylene glycol-formal is produced according to the following reaction:
where n is from 10 from about 150 and R comprises H or an alkyl group.
27 . A process as defined in claim 18 , wherein the formaldehyde source comprises paraformaldehyde.
28 . A process as defined in claim 18 , further comprising the step of removing water during formation of the Bis-polyalkylene glycol-formal.