# US 10,479,954 B2 · Intrinsic low friction polyoxymethylene

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- Number: US 10,479,954 B2
- Document ID: US10479954B2
- Status: Granted
- Kind: B2
- Application number: 16/014,696
- Filed: 2018-06-21
- Published: 2018-10-18
- Granted: 2019-11-19
- Earliest claimed: 2013-10-21
- Assignees: Celanese Sales Germany GmbH
- Applicants: Celanese Sales Germany GmbH
- Inventors: Qamer Zia; Oliver Juenger; Jos Bastiaens; Kirsten Markgraf
- Web page: https://patentgrep.com/patent/US10479954B2

## CPC

- C10M 155/02: Monomer containing silicon
- C08K 3/38: Boron-containing compounds
- C08L 59/04: Copolyoxymethylenes
- C08L 83/04: Polysiloxanes
- C08L 91/06: Waxes
- C10M 125/26: Compounds containing silicon or boron, e.g. silica, sand
- C08G 16/02: of aldehydes
- C08K 2003/385: {Binary compounds of nitrogen with boron}
- C08L 59/00: Compositions of polyacetals; Compositions of derivatives of polyacetals (of polyvinyl acetals C08L29/14)
- C08L 61/00: Compositions of condensation polymers of aldehydes or ketones (with polyalcohols C08L59/00; with polynitriles C08L77/00); Compositions of derivatives of such polymers
- C10M 2229/02: Unspecified siloxanes; Silicones
- C10M: LUBRICATING COMPOSITIONS (well drilling compositions C09K8/02); USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION (mould release, i.e. separating, agents for metals B22C3/00, for plastics or substances in a plastic state, in general B29C33/56, for glass C03B40/02; textile lubricating compositions D06M11/00, D06M13/00, D06M15/00; immersion oils for microscopy G02B21/33)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A tribologically modified polyoxymethylene polymer composition is disclosed. The polyoxymethylene polymer composition is comprised of a polyoxymethylene polymer and at least one tribological modifier. The tribological modifier may comprise at least one tribological modifier comprising an ultra-high molecular weight silicone having a kinematic viscosity of greater than 100,000 mm2 s−1. The composition may exhibit a dynamic coefficient of friction against a counter-material of from about 0.01 to about 0.15. The polyoxymethylene polymer compositions provide polymer articles with improved tribological properties and mechanical properties.

## Claims

### Claim 1

A polyoxymethylene polymer composition, the polyoxymethylene polymer composition comprising;
a polyoxymethylene copolymer having a melt flow index of less than about 50 g/10 min, and
first tribological modifier comprising an ultra-high molecular weight silicone having a kinematic viscosity at 40° C. of greater than 100,000 mm2 s−1, the ultra-high molecular weight silicone being present in the polymer composition in an amount from about 0.1 to about 10% by weight;
a second tribological modifier comprising polytetrafluoroethylene particles, ultra-high molecular weight polyethylene, or a silicone oil having an average molecular weight of at least 5,000 g/mol and less than 75,000 g/mol and having a kinematic viscosity at 40° C. of greater than 100 mm2 s−1 and less than 15,000 mm2 s−1, or mixtures thereof; and
reinforcing fibers present in the composition in an amount of at least 10% by weight and up to 50% by weight.

### Claim 2 (depends on 1)

The polymer composition of claim 1, wherein the second tribological modifier comprises the silicone oil.

### Claim 3 (depends on 1)

The polyoxymethylene polymer composition as defined in claim 1, wherein the second tribological modifier comprises the polytetrafluoroethylene particles, the polytetrafluoroethylene particles being present in the polymer composition in an amount from about 0.1 to about 50% by weight.

### Claim 4 (depends on 1)

The polyoxymethylene polymer composition as defined in claim 1, wherein the second tribological modifier comprises the ultra-high molecular weight polyethylene particles.

### Claim 5 (depends on 1)

The polymer composition of claim 1, wherein the composition further contains a nucleant comprising an oxymethylene terpolymer.

### Claim 6 (depends on 5)

The polymer composition of claim 5, wherein the nucleant is present in the composition in an amount from about 0.01% by weight to about 2% by weight.

### Claim 7 (depends on 1)

The polymer composition of claim 1, wherein the polyoxymethylene copolymer contains comonomer units in an amount from about 0.5 mol % to about 5 mol %.

### Claim 8 (depends on 1)

The polymer composition of claim 1, wherein the polyoxymethylene copolymer has a melt flow index of greater than about 5 g/10 min.

### Claim 9 (depends on 1)

The polymer composition of claim 1, wherein the composition has a modulus of elasticity measured according to ISO Test No. 527 of at least about 2000 MPa.

### Claim 10 (depends on 1)

The polymer composition of claim 1, wherein the reinforcing fibers comprise glass fibers.

### Claim 11 (depends on 1)

The polymer composition as defined in claim 1, wherein the ultra-high molecular weight silicone is present in the polymer composition in an amount of from about 1 weight % to about 6 weight %.

### Claim 12 (depends on 1)

The polymer composition as defined in claim 1, wherein the polyoxymethylene polymer is present in the polymer composition in an amount of at least 70% by weight.

### Claim 13 (depends on 2)

The polymer composition of claim 2, wherein the silicone oil is present in the polymer composition in an amount of from about 0.5% by weight to about 5% by weight.

### Claim 14 (depends on 3)

The polymer composition as defined in claim 3, wherein the polytetrafluoroethylene particles are present in the polymer composition in an amount from about 1% to about 10% by weight.

### Claim 15 (depends on 4)

The polymer composition as defined in claim 4, wherein the ultra-high molecular weight polyethylene is present in the polymer composition in an amount of from about 2.5% to about 20% by weight, the ultra-high molecular weight polyethylene having a molecular weight of greater than about 2.0×106 g/mol.

### Claim 16 (depends on 1)

The polymer composition as defined in claim 1, wherein the polymer composition contains a silicone oil and polytetrafluoroethylene particles.

### Claim 17 (depends on 16)

A polymer article made from the composition of claim 16, the polymer article comprising a gear, a lever, a cam, a roller, a sliding element, a pulley, a latch, a claw, a wiper arm, a conveyor component, a medical inhaler, or a medical injector.