PARTICULATE COMPOSITION FOR PRODUCTION OF LOW-WEAR NONSTICK COATINGS, AND COATED PRODUCT

Abstract

A composition for producing particulate coatings for printing machine cylinders or printing machine cylinder covers that are nonstick and wear resistant. The composition includes at least one sol-gel precursor compound and a mixture of hard solid-state particles, such as silicon carbide. One type of particles has a Sauter diameter d.sub.32 of between 1.0 ?m and 2.0 ?m and the other type of less than 1.0 ?m. A mixing ratio of the two types of hard solid-state particles lies in the range from 1.5:1 to 1:1.5.

Claims

1. A composition for producing particulate coatings, comprising the following components: A) at least one sol-gel precursor compound; and B1) solid-state particles P1) having a Sauter diameter d.sub.32 in the range from 1.0 ?m to 2.0 ?m, measured by dynamic light scattering; and B2) solid-state particles P2) having a Sauter diameter d.sub.32 of less than 1.0 ?m, measured by dynamic light scattering; and wherein a ratio of solid-state particles P1) to solid-state particles P2) lies in a range from 1.5:1 to 1:1.5.

2. The composition according to claim 1, wherein component A) is at least one of hydrolyzable or condensable.

3. The composition according to claim 1, wherein component A) comprises at least one element selected from the group consisting of B, Si, Al, Zr and Ti.

4. The composition according to claim 1, wherein component A) comprises at least one alkoxide.

5. The composition according to claim 1, wherein component A) comprises at least one organic silicon compound.

6. The composition according to claim 1, wherein component A) comprises at least one silicon oxide sol.

7. The composition according to claim 1, wherein component A) comprises at least one compound selected from organic silicon compounds of the formula (I)
R.sup.1.sub.aSi(R.sup.2).sub.4-a(I) wherein: a is 1, 2 or 3; R.sup.1 is independently a saturated or unsaturated hydrocarbyl radical which has 1 to 20 carbon atoms and may have one or more double bonds and/or triple bonds and may be substituted or unsubstituted; R.sup.2 is independently H, halogen or OR.sup.4, where R.sup.4 is a saturated or unsaturated hydrocarbyl radical which has 1 to 20 carbon atoms and may have one or more double bonds and/or triple bonds and may be substituted or unsubstituted; and hydrolysis products and condensation products thereof.

8. The composition according to claim 7, wherein component A) comprises at least one compound selected from compounds of the formula (I), in which: R.sup.1 is independently C.sub.1-C.sub.20-alkyl, C.sub.2-C.sub.20-alkenyl, C.sub.2-C.sub.20-alkynyl, C.sub.6-C.sub.14-aryl, C.sub.7-C.sub.20-aralkyl, C.sub.7-C.sub.20-alkylaryl, C.sub.8-C.sub.20-arylalkenyl, C.sub.8-C.sub.20-alkenylaryl, C.sub.8-C.sub.20-arylalkynyl or C.sub.8-C.sub.20-alkynylaryl, where the R.sup.1 radicals may bear one or more substituents selected from halogens and optionally substituted amino groups, aldehyde groups, keto groups, C.sub.1-C.sub.20-alkylcarbonyl groups, carboxy groups, mercapto groups, cyano groups, hydroxy groups, C.sub.1-C.sub.20-alkoxy groups, C.sub.1-C.sub.20-alkoxycarbonyl groups, sulfonic acid groups, phosphoric acid groups, acryloyloxy groups, methacryloyloxy groups, epoxy groups and vinyl groups; R.sup.2 is independently H, halogen, C.sub.1-C.sub.20-alkoxy, C.sub.6-C.sub.14-aryloxy or C.sub.1-C.sub.20-alkoxy-C.sub.1-C.sub.20-alkoxy; and the hydrolysis products and condensation products thereof.

9. The composition according to claim 1, wherein an amount of component A) lies in a range from 20% to 80% by weight, based on an overall composition.

10. The composition according to claim 1, wherein the solid-state particles P1) and the solid-state particles P2) each have a Mohs hardness of 7 or more.

11. The composition according to claim 10, wherein the solid-state particles P1) and the solid-state particles P2) are each independently selected from quartz particles, corundum particles, silicon carbide particles, diamond particles, and mixtures thereof,

12. The composition according to claim 10, wherein the solid-state particles P1) and the solid-state particles P2) are mixtures of silicon carbide particles.

13. The composition according to claim 1, wherein the amount of component B) is in the range from 5% to 30% by weight, based on the overall composition.

14. A coated surface, comprising: a composition according to claim 1 forming a coating on a metal surface, a ceramic surface, a plastic surface, a glass surface, a stone surface, a wood surface, or combinations thereof.

15. A coated product for a printing machine, the coated product comprising a contact surface that has been coated, at least in some region thereof, with a composition according to claim 1, and wherein the contact surface is configured to at least intermittently touch a print material during a printing operation.

16. The coated product according to claim 15, being an exchangeable cylinder cover for a sheet-transporting cylinder of a rotary printing machine or a sheet-transporting cylinder for a rotary printing machine.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0071] FIGS. 1-4 are high resolution photographs of cylinder covers produced by a method as described above.

[0072] FIG. 5 is a high-resolution photograph of a cylinder cover produced by a method according to the invention.

DESCRIPTION DETAILED DESCRIPTION OF THE INVENTION

[0073] FIG. 1 shows a photograph of a cylinder cover that has been produced by the method described above. This was done using a silicon oxide sol that comprised solely solid-state particles P1), namely silicon carbide particles that had a Sauter diameter d.sub.32 in the range from 1.0 ?m to 2.0 ?m. The surface structure was not of good suitability for practical use in the printing machine.

[0074] FIG. 2 shows a photograph of a cylinder cover that has been produced by the method described above. This was done using a silicon oxide sol that comprised solely solid-state particles P2), namely silicon carbide particles that had a Sauter diameter d.sub.32 of less than 1.0 ?m. The surface structure was not of good suitability for practical use in the printing machine.

[0075] FIG. 3 shows a photograph of a cylinder cover that has been produced by the method described above. This was done using a silicon oxide sol comprising silicon carbide particles, specifically a 2:1 mixture of solid-state particles P2) to solid-state particles P1). The surface structure was not of good suitability for practical use in the printing machine.

[0076] FIG. 4 shows a photograph of the cylinder cover depicted in FIG. 3, where the cylinder cover was additionally coated with a protective sol-gel layer without addition of solid-state particles. The surface structure was not of good suitability for practical use in the printing machine.

[0077] FIG. 5 shows a photograph of a cylinder cover according to the invention that has been produced by the method described above. This was done using a silicon oxide sol comprising silicon carbide particles, specifically a 1:1 mixture of solid-state particles P2) to solid-state particles P1), which was additionally coated with two protective sol-gel layers without the addition of solid-state particles. The surface structure was of very good suitability for practical use in the printing machine.