High friction polyurethane elastomers having improved abrasion resistance

Claim 2

A composition of matter comprising a polyurethane elastomer having improved abrasion resistance with no significant loss in friction prepared by mixing A) a polyurethane prepolymer, B) a curative, and C) a liquid, non-reactive polydimethylsiloxane, wherein C) is present in a concentration of about 0.5 to about 25% based on the combined weight of A) plus B), and curing the mixture to form the elastomer.

Claim 3

The composition of claim 1 wherein the polyurethane prepolymer is prepared from a diisocyanate selected from the group consisting of paraphenylene diisocyanate, tolidene diisocyanate, isophorone diisocyanate, 4,4′-methylene bis (phenylisocyanate), toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, dibenzyl-4,4′-diisocyanate, stilbene-4,4′-diisocyanate, benzophenone-4,4′-diisocyanate, 1,3-and 1,4-xylene diisocyanates, 1,6-hexamethylene diisocyanate, 1,3-cyclohexyl diisocyanate, 1,4-cyclohexyl diisocyanate, the three geometric isomers of 1,1′-methylene-bis(4-isocyanatocyclohexane), and mixtures of the foregoing.

Claim 4

The composition of claim 2 wherein the diisocyanate is reacted with a polyol selected from the group consisting of polyether polyols, polyester polyols, and hydrocarbon polyols, having a number average molecular weight of at least 250.

Claim 5

The composition of claim 3 wherein the polyol is a polyalkyleneether polyol represented by the general formula HO(RO) n H, wherein R is an alkylene radical and n is an integer large enough that the polyether polyol has a number average molecular weight of at least 250.

Claim 6

The composition of claim 1 wherein the curative is selected from the group consisting of diamines, polyols, and blends thereof having a melting point below 140° C.

Claim 7

The composition of claim 5 wherein the curative is selected from the group consisting of 1,4-butanediol, hydroquinone-bis-hydroxyethyl ether, 1,4-cyclohexane dimethanol, trimethylolpropane, aliphatic tetrols, 4,4′-methylenedianiline, 2,2′,5-trichloro-4,4′-methylenediamines, naphthalene-1,5-diamine, ortho, meta, and para-phenylene diamines, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, 4,4′-methylene-bis(3-chloroaniline), 4,4′-methylene-bis(3-chloro-2,6-diethylaniline), diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-amino-benzoate, 1,2-bis(2-aminophenylthio)ethane, and methylenedianiline-sodium chloride complex, including the derivatives and mixtures of the foregoing.

Claim 10

The method of claim 7 wherein the polyurethane prepolymer is prepared from a diisocyanate selected from the group consisting of paraphenylene diisocyanate, tolidene diisocyanate, isophorone diisocyanate, 4,4′-methylene bis (phenylisocyanate), toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, dibenzyl-4,4′-diisocyanate, stilbene-4,4′-diisocyanate, benzophenone-4,4′-diisocyanate, 1,3- and 1,4-xylene diisocyanates, 1,6-hexamethylene diisocyanate, 1,3-cyclohexyl diisocyanate, 1,4-cyclohexyl diisocyanate, the three geometric isomers of 1,1′-methylene-bis(4-isocyanatocyclohexane), and mixtures of the foregoing.

Claim 11

The method of claim 8 wherein the diisocyanate is reacted with a polyol selected from the group consisting of polyether polyols, polyester polyols, and hydrocarbon polyols, having a number average molecular weight of at least 250.

Claim 12

The method of claim 9 wherein the polyol is a polyalkyleneether polyol represented by the general formula HO(RO) n H, wherein R is an alkylene radical and n is an integer large enough that the polyether polyol has a number average molecular weight of at least 250.

Claim 13

The method of claim 7 wherein the curative is selected from the group consisting of diamines, polyols, and blends thereof having a melting point below 140° C.

Claim 14

The method of claim 11 wherein the curative is selected from the group consisting of 1,4-butanediol, hydroquinone-bis-hydroxyethyl ether, 1,4-cyclohexane dimethanol, trimethylolpropane, aliphatic tetrols, 4,4′-methylenedianiline, 2,2′,5-tricbloro-4,4′-methylenediamines, naphthalene-1,5-diamine, ortho, meta, and para-phenylene diamines, toluene-2,4-diamine, dichlorobenzidine, diphenylether-4,4′-diamine, 4,4′-methylene-bis(3-chloroaniline), 4,4′-methylene-bis(3-chioro-2,6-diethylaniline) diethyl toluene diamine, tertiary butyl toluene diamine, dimethylthio-toluene diamine, trimethylene glycol di-p-amino-benzoate, 1,2-bis(2-aminophenylthio)ethane and methylenedianiline-sodium chloride complex, including the derivatives and mixtures of the foregoing.

Claim 15

An article of manufacture comprising a polyurethane elastomer and about 0.5% to about 25% based on the weight of the elastomer of a non-reactive, liquid polydimethylsiloxane, whereby the abrasion resistance of the article is improved with no significant loss in friction.

Claim 16

An article of manufacture comprising a polyurethane elastomer and about 0.5% to about 25% based on the weight of the elastomer of a non-reactive, liquid polydimethylsiloxane, whereby the abrasion resistance of the article is improved with no significant loss in friction.

Claim 17

The article of manufacture of claim 13 wherein the article is a railroad side bearing pad.

Claim 18

The article of manufacture of claim 13 wherein the article is a skate wheel.

Claim 19

The article of manufacture of claim 13 wherein the article is a tire.

Claim 20

The article of manufacture of claim 13 wherein the article is a track pad.

Claim 21

The article of manufacture of claim 13 wherein the article is an elastomeric friction brake.

Claim 22

The article of manufacture of claim 13 wherein the article is a scraper blade.