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EP-4739738-A2 - LUBRICATING AND LOW COEFFICIENT OF FRICTION COATING COMPOSITION FOR RIGID SUBSTRATES

EP4739738A2EP 4739738 A2EP4739738 A2EP 4739738A2EP-4739738-A2

Abstract

A coating composition for coating rigid substrates, including a binder resin, a lubricating component including a wax, and a solvent. The coating composition may further include a silicone resin. The binder resin is at least one of a polyamide imide, epoxy, silicone polyester, and polyurethane resin. The wax is at least one of a carnauba wax, a polyethylene wax, polypropylene wax, polyamide wax, and a Fischer-Tropsch wax. The coating composition is wear resistant and is substantially free of per-fluoroalkyl substances (PFAS) and N-methyl pyrrolidone (NMP).

Inventors

  • MILANI, Jacopo
  • JONES, Mark Christopher
  • MCBRIDE, Katy
  • SEDWELL, Graham William
  • KUMAR, BHAWESH
  • SARAF, CHINMAY MANGESH
  • KHAWARIZMI, Ryan Muhammad
  • YETTER, JR. JOHN ROBERT
  • KUMAR, MUKESH

Assignees

  • PPG Industries Ohio Inc.

Dates

Publication Date
20260513
Application Date
20240507

Claims (20)

  1. CLAIMS What is claimed is: 1. A coating composition for a rigid substrate, comprising: a binder resin; a lubricating component comprising a wax; and a solvent.
  2. 2. The coating composition of claim 1, wherein the binder resin is selected from polyamide imide, epoxy, silicone polyester, and polyurethane resin.
  3. 3. The coating composition of either claim 1 or claim 2, wherein the lubricating component further comprises a silicone resin.
  4. 4. The coating composition of claim 3, wherein the silicone resin is selected from poly(aryl-alkylsilsesquioxane) and poly(alkylsilsesquioxane).
  5. 5. The coating composition of any one of claims 1-4, wherein the wax has a melting point from 70 o C to 140 o C, as determined by Differential Scanning Calorimetry (DSC) according to ASTM E794 – 06(2018)
  6. 6. The coating composition of any one of claims 1-5, wherein the wax is at least one of a carnauba wax, a polyethylene wax, polypropylene wax, polyamide wax, and a Fischer- Tropsch wax.
  7. 7. The coating composition of any one of claims 1-6, wherein the binder resin comprises from 20 to 80 wt.% of the coating composition, based on a total wet weight of the coating composition.
  8. 8. The coating composition of any one of claims 1-7, wherein the binder resin comprises from 35 to 78 wt.% of the coating composition, based on a total wet weight of the coating composition.
  9. 9. The coating composition of any one of claims 1-8, wherein the wax comprises from 0.05 to 10 wt.% of the coating composition, based on a total wet weight of the coating composition.
  10. 10. The coating composition of any one of claims 1-9, wherein the silicone resin comprises 1 to 10 wt. % of the coating composition, based on the total wet weight of the coating composition.
  11. 11. The coating composition of any one of claims 1-10, wherein the wax comprises particles of wax having an average particle size (D50) of less than 12 microns, as determined by dynamic light scattering ISO 13320-1.
  12. 12. The coating composition of any one of claims 1-11, comprising a total amount of perfluoroalkyl substances (PFAS) of 1 ppm or less, based on a total weight of the coating composition.
  13. 13. The coating composition of any one of claims 1-12, comprising a total amount of N- methyl pyrrolidone (NMP) of 1 ppm or less, based on a total weight of the coating composition.
  14. 14. A method of coating a rigid substrate, comprising: applying the coating composition of any one of claims 1-13 to the rigid substrate; and curing the coating composition at a temperature from 170 to 240 o C.
  15. 15. A coated rigid substrate, comprising: a rigid substrate; and a coating on the rigid substrate, comprising: a binder resin; and a lubricating component comprising a wax.
  16. 16. The coated rigid substrate of claim 15, wherein the binder resin is selected from polyamide imide, epoxy, silicone polyester, and polyurethane resin.
  17. 17. The coated rigid substrate of either claim 15 or claim 16, wherein the lubricating component further comprises a silicone resin.
  18. 18. The coated rigid substrate of claim 17, wherein the silicone resin is selected from poly(aryl-alkylsilsesquioxane) and poly(alkylsilsesquioxane).
  19. 19. The coated rigid substrate of any one of claims 15-18, wherein the wax has a melting point from 70 o C to 140 o C, as determined by ASTM D87.
  20. 20. The coated rigid substrate of any one of claims 15-19, wherein the wax is at least one of a carnauba wax, a polyethylene wax, polypropylene wax, polyamide wax, and a Fischer- Tropsch wax.

Description

LUBRICATING AND LOW COEFFICIENT OF FRICTION COATING COMPOSITION FOR RIGID SUBSTRATES CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No.63/512,505 entitled “LUBRICATING AND LOW COEFFICIENT OF FRICTION COATING COMPOSITION FOR RIGID SUBSTRATES”, filed on July 7, 2023, and U.S. Provisional Application No.63/591,146 entitled “LUBRICATING AND LOW COEFFICIENT OF FRICTION COATING COMPOSITION FOR RIGID SUBSTRATES”, filed on October 18, 2023, both of which are incorporated by reference in their entireties. GOVERNMENT LICENSE RIGHTS [0002] This invention was made with government support under Government Contract No. W911NF-17-2-0227 awarded by the U.S. Army Contracting Command on behalf of the U.S. Army Research Laboratory (ARL). The government may have certain rights in the invention. FIELD [0003] The present disclosure relates to a lubricating coating composition with a low coefficient of friction, which may be applied to rigid substrates. BACKGROUND [0004] Rigid metallic parts of mechanical devices may experience a variety of contact and frictional forces that can cause wear and deterioration upon sustained use. Coatings may be applied to these metal parts to enhance wear resistance, prevent premature failure, and/or suppress noise. Known coatings typically contain per/polyfluoroalkyl substances (PFAS) and/or solvents such as N-methyl pyrrolidone (NMP) which are progressively subjected to increased regulation. [0005] Therefore, improvements in such coatings are desired. SUMMARY [0006] The present disclosure provides a coating composition for a rigid substrate, including a binder resin, a lubricating component including a wax, and a solvent. The binder resin is selected from polyamide imide, epoxy, silicone polyester, and polyurethane resin. The wax may be at least one of a carnauba, polyethylene, and Fisher-Tropsch wax. The lubricating component further includes a silicone resin. The coating composition is wear resistant and substantially free of perfluoroalkyl substances and N-methyl pyrrolidone. [0007] In one form thereof, the present disclosure provides a method of coating a rigid substrate including applying a coating composition to the rigid substrate and curing the coating composition at a temperature from 170oC to 240oC. The coating composition includes a binder resin, a lubricating component including a wax, and a solvent. [0008] In another form thereof, the present disclosure also provides a coated rigid substrate including a rigid substrate and a coating on the rigid substrate. The coating on the rigid substrate includes a binder resin and a lubricating component including a wax. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description taken in conjunction with the accompanying drawings. These above-mentioned and other features of the disclosure may be used in any combination or permutation. [0010] FIG. 1 is a graph of friction test results illustrating the coefficient of friction versus time for comparative coating 1 and inventive coatings 1-3; [0011] FIG. 2 is a graph of friction test results illustrating the coefficient of friction versus time for comparative coating 1 and inventive coatings 3-4; [0012] FIG. 3 is a graph of friction test results illustrating the coefficient of friction versus time for comparative coating 2 and inventive coatings 3 and 5; [0013] FIG. 4 is a graph of friction test conducted at room temperature results illustrating the coefficient of friction versus time for comparative coating 3 and inventive coatings 6-11; [0014] FIG. 5 is a graph of friction test conducted at room temperature results illustrating the coefficient of friction versus time for comparative coating 4 and inventive coatings 12-15; and [0015] FIG.6 is a graph of friction test conducted at elevated temperature of 150oC results illustrating the coefficient of friction versus time for comparative coating 5 and inventive coatings 16-20. [0016] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate the disclosure, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner. DETAILED DESCRIPTION [0017] The present disclosure provides a coating composition with a low coefficient of friction, which may be applied to rigid substrates. [0018] I. Definitions [0019] For purposes of the following detailed description, it is to be understood that the disclosure may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples or where otherwise indicated, all numbers expressing, for example, quantitie