Claims
- 1. A method of curing a polymer thick film on a substrate comprising the steps of:
- (1) providing a polymer thick film composition comprising, by weight:
- (a) about 3-15 pars of at least one thermoplastic vinyl acetate/vinyl chloride/dicarboxylic acid multipolymer resin;
- (b) a second thermoplastic resin selected from the group consisting of:
- (i) about 1-6 parts of at least one thermoplastic polyurethane resin;
- (ii) about 3-10 parts of at least one thermoplastic polyester resin; or
- (iii) about 1-10 parts of a mixture of at least one thermoplastic polyurethane and at least one polyester resin;
- (c) about 0.05-1 parts of a tertiary amine;
- (d) an effective amount of at least one organic solvent capable of substantially dissolving (a), (b), and (c) ingredients; and
- (e) about 50-80 parts silver flake;
- (2) applying said composition to a substrate; and
- (3) curing said composition onto said substrate by exposing the coated substrate to elevated temperatures.
- 2. The method of claim 1, wherein said applying step (2) is a screen-printing operation.
- 3. The method of claim 1, wherein said curing step is carried out in a convention oven at a temperature from about 110.degree. C. to about 150.degree. C. for a period of time from about 5 minutes to about 30 minutes.
- 4. The process of claim 1 wherein said solvent is at least one nonhydrocarbon polar organic solvent capable of dissolving the resin system, the amount of said solvent being sufficient to dissolve the resin system and to adjust the viscosity of said polymer thick film composition in order to make it applicable to a membrane switch substrate.
- 5. The process of claim 1 wherein the amount of said solvent is from about 20 parts to about 40 parts by weight in said polymer thick film composition.
- 6. The process claim 5 wherein said solvent is selected from the group consisting of carbitol, carbitol acetate, butyl carbitol, butyl carbitol acetate, butyolactone, acetone, methyl ethyl ketone, cyclohexanone, dibasic ester solvent, and diglyme.
- 7. The process of claim 6 wherein said solvent is carbitol acetate.
- 8. The process claim 1 wherein said vinyl acetate/vinyl chloride/dicarboxylic acid multipolymer is a terpolymer of vinyl acetate, vinyl chloride, and an ethylenically unsaturated dicarboxylic acid.
- 9. The process of claim 8 wherein said terpolymer of vinyl acetate, vinyl chloride, and an ethylenically unsaturated carboxylic acid is a vinyl acetate/vinyl chloride/maleic acid terpolymer.
- 10. The process of claim 1 wherein said polyurethane resin is a linear aliphatic polyester polyurethane resin.
- 11. The process of claim 1 wherein said polyester resin is a linear aromatic polyester resin.
- 12. The process of claim 1 wherein said tertiary amine is selected from the group consisting of N,N-dimethyl benzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, N,N-dimethyl-p-anisidine, p-halogen-N,N-dimethylaniline, 2-N-ethylanilino ethanol, tri-n-butylamine, pyridine, quinoline, N-methylvorpholine, triethanolamine, triethylenediamine, N,N,N',N'-tetramethylbutanediamine, N-methylpiperidine.
- 13. The process of claim 12 wherein said tertiary amine is triethanolamine.
- 14. The process of claim 1 wherein said polymer thick film composition comprises, by weight:
- (a) about 4.5-10 parts of a thermoplastic vinyl acetate/vinyl chloride/maleic acid tripolymer;
- (b) a second thermoplastic resin selected from the group consisting of:
- (1) about 2.5-3.5 parts of a linear aliphatic polyester polyurethane resin; and
- (2) about 3.5-6 parts of a linear aromatic polyester resin;
- (c) about 0.1-0.5 parts of triethanolamine;
- (d) about 25-35 parts of carbitol acetate; and
- (e) about 55-70 parts of silver flake.
Parent Case Info
This application is a division of application Ser. No. 07/518,052 filed May 2, 1990, now U.S. Pat. No. 5,089,17
US Referenced Citations (8)
Non-Patent Literature Citations (4)
Entry |
Union Carbide Product Data Sheet for VMCA vinyl acetage/vinyl chloride/maleic acid tripolymer. |
B.F. Goodrich Product Data Sheet for ESTANE 5703 polyurethane resin. |
B.F. Goodrich Product Data Sheet for VITEL PE-222 polyester resin. |
D. Bowns "Specialty Inks for Membrane Switches", Screen Printing, May, 1983. |
Divisions (1)
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Number |
Date |
Country |
Parent |
518052 |
May 1990 |
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