Method of producing a protective finish on a substrate

• US 5,401,541 A
• Filed: 09/22/1993
• Issued: 03/28/1995
• Est. Priority Date: 08/23/1988
• Status: Expired due to Fees

• Current Assignee: Thor Radiation Research, Inc
• Original Assignee: Thor Radiation Research, Inc
• Inventors: Hodnett, William P. III
• Primary Examiner(s): PIANALTO, BERNARD D
• Application Number:
  US08/125,335
• Time in Patent Office: 552 Days
• Field of Search: 427/487, 427/532, 427/585.5, 427/412.1, 427/412.5
• US Class Current: 427/487
• CPC Class Codes: B05D 2420/02 second layer from the substrate side
• CPC Class Codes: B05D 2420/03 third layer from the substrate side
• CPC Class Codes: B05D 2425/01 top layer/ last layer, i.e. first layer from the top surface
• CPC Class Codes: B05D 2502/00 Acrylic polymers
• CPC Class Codes: B05D 2503/00 Polyurethanes
• CPC Class Codes: B05D 3/067 Curing or cross-linking the coating
• CPC Class Codes: B05D 7/576 each layer being cured, at least partially, separately
• CPC Class Codes: C08F 220/00 Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: C09D 5/00 Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced electrically insulating plastics, resins or waxes H01B3/30; Filling pastes
• CPC Class Codes: Y10T 428/24983 Hardness
• CPC Class Codes: Y10T 428/31573 Next to addition polymer of ethylenically unsaturated monomer
• CPC Class Codes: Y10T 428/31576 Ester monomer type [polyvinylacetate, etc.]
• CPC Class Codes: Y10T 428/31605 Next to free metal
• CPC Class Codes: Y10T 428/31692 Next to addition polymer from unsaturated monomers

Abstract

This invention relates to a coating system which forms a highly abrasion resistant, chemical resistant, impact resistant protective finish for a substrate. The coating system is based upon using two coatings of different characteristics but having excellent adhesion to one another. The outermost or surface coating layer is a highly crosslinked hard polymer, which is adhered to an underlying base coating layer of a compatible softer polymer. The outer hard polymer preferably comprises a highly crosslinked acrylic copolymer derived from at least 40 percent by weight of a multifunctional aliphatic acrylate monomer of three or more functional groups, while the underlying softer polymer preferably comprises a crosslinked aliphatic urethane acrylate copolymer and the multifunctional aliphatic acrylate monomer of three or more functional groups.

Claims

1. A method of producing a highly scratch resistant, chemical resistant, impact resistant protective finish on a substrate, which comprises applying to the substrate a first coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of an aliphatic urethane acrylated copolymer and a lesser proportion of a multifunctional acrylate monomer of three to six functional groups, subjecting the first coating layer to radiation to polymerize the coating composition and form a relatively soft radiation polymerized urethane copolymer, applying to the thus polymerized first coating layer, a second coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups, and subjecting the second coating layer to radiation to polymerize the coating composition and form a relatively hard radiation polymerized acrylic outer coating layer.

2. The method of claim 1 wherein said step of applying the second coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups to the polymerized first coating layer includes applying the coating composition diluted with a solvent to a thickness of about 0.01 to about 1 mils.

3. The method of claim 2 wherein the solvent is methyl ethyl ketone.

4. The method of claim 1 wherein said step of applying the second coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups to the polymerized first coating layer includes applying the coating composition diluted with a small monofunctional monomer to a thickness of about 0.01 to about 1 mils.

5. The method of claim 4 wherein the small monofunctional monomer is tetrahydrofurfuryl acrylate.

6. The method of claim 1, wherein the substrate is a polymeric substrate.

7. The method of claim 6, wherein the polymeric substrate is a polyester film.

13. The method of claim 7, wherein the substrate is a polymeric substrate.

14. The method of claim 13, wherein the polymeric substrate is a polyester film.

8. A method of producing a highly scratch resistant, chemical resistant, impact resistant protective finish on a substrate, which comprises applying to the substrate a primer coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of a multifunctional acrylate monomer of three to six functional groups, subjecting the primer coating layer to radiation to polymerize the coating composition, applying to the cured primer coating layer a first coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of an aliphatic urethane acrylated copolymer and a lesser proportion of the multifunctional acrylate monomer of three to six functional groups, subjecting the first coating layer to radiation to polymerize the coating composition and form a relatively soft radiation polymerized urethane copolymer, applying to the thus polymerized first coating layer, a second coating layer of the radiation polymerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups, and subjecting the second coating layer to radiation to polymerize the coating composition and form a relatively hard radiation polymerized acrylic outer coating layer.

9. The method of claim 8 wherein said step of applying the second coating layer of a radiation polymerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups to the polymerized first coating layer includes applying the coating composition diluted with a solvent to a thickness of about 0.01 to about 1 mils.

10. The method of claim 9 wherein the solvent is methyl ethyl ketone.

11. The method of claim 8 wherein said step of applying the second coating layer of a radiation polylmerizable coating composition formed from at least 40 percent by weight of the multifunctional acrylate monomer of three to six functional groups to the polymerized first coating layer includes applying the coating composition diluted with a small monofunctional monomer to a thickness of about 0.01 to about 1 mils.

12. The method of claim 11 wherein the small monofunctional monomer is tetrahydrofurfuryl acrylate.