TREATED PLASTIC SURFACES HAVING IMPROVED CLEANING PROPERTIES

1 . A self cleaning thermoplastic substrate, comprising: a thermoplastic substrate surface having secured thereto a plurality of composite particles, the composite particles comprising a mixture of a thermoplastic resin powder particle, a tackifier and a hydrophobically treated inorganic particle whereby the tackifier adheres the hydrophobically treated particles to the resin powder particle.

2 . The self cleaning thermoplastic substrate of claim 1 wherein the thermoplastic substrate is selected from the group consisting of polyvinyl chloride, polyethylene, polyvinylidene fluoride, polypropylene, and acrylonitrile butadiene styrene terpolymer.

3 . The self cleaning thermoplastic substrate of claim 1 wherein the thermoplastic resin powder is selected from the group consisting of polyvinyl chloride, polymethyl methacrylate, polyolefin, copolymer of ethylene acrylate, copolymer of ethylene methacrylate and terpolymer of ethylene, vinyl acetate and carbon monoxide, and mixtures thereof.

4 . The self cleaning thermoplastic substrate of claim 1 wherein the composite powder is on the surface in an amount ranging from about 0.1 wt. % to about 50 wt. % based on the weight of the self cleaning thermoplastic substrate.

5 . The self cleaning thermoplastic substrate of claim 1 wherein the hydrophobically treated particle is selected from the group consisting of silicate, metal oxide, calcium carbonate, barium sulfate, metal powder, silica and mixtures thereof.

6 . The self cleaning thermoplastic substrate of claim 1 wherein the hydrophobically treated particle is fumed silica.

7 . The self cleaning thermoplastic substrate of claim 1 wherein hydrophobically treated particle is titanium dioxide.

8 . The self cleaning thermoplastic substrate of claim 1 wherein the hydrophobically treated particles are treated with a surface treatment selected from the group consisting of organo-silane; organo-siloxane; fluoro-silane; organo-phosphonate; organo-phosphoric acid compound; organo-phosphinate; organo-sulfonic compound; hydrocarbon-based carboxylic acid; hydrocarbon-based carboxylic acid derivative; hydrocarbon-based carboxylic acid polymer; hydrocarbon-based amide; low molecular weight hydrocarbon wax; low molecular weight polyolefin; low molecular weight polyolefin co-polymer; hydrocarbon-based polyol; hydrocarbon-based polyol derivative; alkanolamine; alkanolamine derivative; organic dispersing agent; and mixtures thereof.

9 . The self cleaning thermoplastic substrate of claim 8 wherein the organo-silane is represented by the structural formula

Si(R 1 )(R 2 )(R 3 )(R 4 )  (I)

wherein at least one R is a non-hydrolyzable organic group; and at least one R is a hydrolyzable group.

10 . The self cleaning thermoplastic substrate of claim 1 wherein the ratio of the thermoplastic resin powder particles to hydrophobically treated particles of the composite ranges from about 10:1 to about 1:10.

11 . The self cleaning thermoplastic substrate of claim 1 wherein the tackifier is a polysiloxane.

12 . The self cleaning thermoplastic substrate of claim 11 wherein the polysiloxane has the structural formula

Me 3 SiO[SiOMeR 7 ] x —[SiOMe 2 ] y —SiMe 3 ,

where x and y are independently integers from 0 to 200 and R 7 is a saturated or unsaturated linear or branched unsubstituted or heteroatom-substituted hydrocarbon containing 1 to about 20 carbon atoms.

13 . The self cleaning thermoplastic substrate of claim 11 wherein the polysiloxane is selected from the group consisting of polydimethylsiloxane, vinyl phenylmethyl terminated dimethyl siloxane, divinylmethly terminated polydimethyl siloxane, and mixtures thereof.

14 . The self cleaning thermoplastic substrate of claim 1 wherein the mixture further comprises an antistatic agent.

15 . The self cleaning thermoplastic substrate of claim 14 wherein the antistatic agent is an ethoxylated amine.

16 . The self cleaning thermoplastic substrate of claim 14 wherein the antistatic agent is a C 13 /C 15 alkyldiethanolamine.

17 . The self cleaning thermoplastic substrate of claim 14 wherein the tackifier is a polysiloxane and the antistatic agent is a C 13 /C 15 alkyldiethanolamine.

18 . A process for making a self cleaning thermoplastic substrate surface, comprising:

mixing a plurality of thermoplastic resin powder particles, a plurality of hydrophobically treated particles and a tackifier to form a composite powder;

extruding a thermoplastic to form a substrate having a surface; and

securing the composite powder to the surface of the thermoplastic substrate by applying the composite powder to the surface as the thermoplastic is being extruded and calendaring or compression molding the substrate.

19 . The process of claim 18 wherein the tackifier is a polysiloxane.

20 . The process of claim 18 wherein the composite powder comprises an antistatic agent.

21 . The process of claim 20 wherein the antistatic agent is a polyethoxylated amine.

22 . The process of claim 20 wherein the antistatic agent is a C 13 /C 15 alkyldiethanolamine.

23 . The process of claim 18 wherein the thermoplastic substrate is selected from the group consisting of polyvinyl chloride, polyethylene, polyvinylidene fluoride, polypropylene, and acrylonitrile butadiene styrene terpolymer.

24 . The process of claim 18 wherein the thermoplastic resin powder is selected from the group consisting of polyvinyl chloride, polymethyl methacrylate, polyolefin, copolymer of ethylene acrylate, copolymer of ethylene methacrylate and terpolymer of ethylene, vinyl acetate and carbon monoxide, and mixtures thereof.

25 . The process of claim 18 wherein the hydrophobically treated particle is selected from the group consisting of silicate, metal oxide, calcium carbonate, barium sulfate, metal powder, silica and mixtures thereof.