Coating agent
A coating agent includes a polyurethane and a hydrocarbon-based synthetic wax.
1. A rubber-metal laminate comprising a metal sheet, a rubber layer and a coating layer in this order, the coating layer being formed from a coating agent comprising 26.9 to 73.1 wt % of a polyurethane, based on the total solid content in the coating agent, and 26.9 to 73.1 wt % of a hydrocarbon-based synthetic wax, based on the total solid content in the coating agent, wherein
the polyurethane is an aromatic-based polyurethane,
the hydrocarbon-based synthetic wax is an acid-modified polyethylene wax, and
the coating agent does not comprise graphite.
2. The rubber-metal laminate according to claim 1 , wherein the laminate further comprises an adhesive layer between the metal sheet and the rubber layer.
3. The rubber-metal laminate according to claim 1 , wherein the laminate further comprises a primer layer between the metal sheet and the rubber layer.
4. The rubber-metal laminate according to claim 3 , wherein the laminate further comprises an adhesive layer between the primer layer and the rubber layer.
5. The rubber-metal laminate according to claim 3 , wherein the primer layer is formed directly on the metal sheet.
6. The rubber-metal laminate according to claim 5 , wherein the primer layer is selected from the group consisting of a zinc phosphate coating, an iron phosphate coating, and a dry-in-place chromate coating.
7. The rubber-metal laminate according to claim 5 , wherein the primer layer is a coating formed by using a vanadium, zirconium, titanium, molybdenum, tungsten, manganese, zinc, or cerium compound.
8. The rubber-metal laminate according to claim 5 , wherein the primer layer includes an organometallic compound containing at least one chelate ring and an alkoxy group.
9. The rubber-metal laminate according to claim 5 , further comprising a layer of vulcanizing adhesive, which is applied directly onto the primer layer.
10. The rubber-metal laminate according to claim 9 , wherein the vulcanizing adhesive is selected from the group consisting of a phenolic resin adhesive, an epoxy resin adhesive, and a polyurethane adhesive.
11. The rubber-metal laminate according to claim 9 , further comprising an unvulcanized rubber compound, which is applied directly onto the vulcanizing adhesive layer.
12. The rubber-metal laminate according to claim 9 , wherein the rubber layer is formed by drying and heating a rubber coating agent, the rubber coating agent being directly applied to the vulcanizing adhesive layer.
13. The rubber-metal laminate according to claim 1 , wherein the laminate is an engine gasket.
14. The rubber-metal laminate according to claim 1 , wherein the coating agent has a solid content concentration of 1 to 20 wt %.
15. The rubber-metal laminate according to claim 1 , wherein the metal sheet is selected from the group consisting of a stainless steel sheet, a mild steel sheet, a galvanized steel sheet, an SPCC steel sheet, a copper sheet, a magnesium sheet, an aluminum sheet, and an aluminum diecast sheet.
16. The rubber-metal laminate according to claim 1 , wherein a thickness of the coating layer formed using the coating agent is in a range of from 0.5 μm to 10 μm.
17. The rubber-metal laminate according to claim 16 , wherein the coating agent is applied to a surface of the rubber layer via a method selected from the group consisting of a dipping method, a spray method, a roll coating method, a flow coating method, and an inkjet method.
18. The rubber-metal laminate according to claim 1 , wherein a softening point of the hydrocarbon-based synthetic wax is in a range of from 100° C. to 170° C.
19. The rubber-metal laminate according to claim 1 , wherein the coating agent does not include any of the following cellulose materials: methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxymethylethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and ethylhydroxyethyl cellulose.