Conductive ink composition

• US 6,322,620 B1
• Filed: 11/16/2000
• Issued: 11/27/2001
• Est. Priority Date: 11/16/2000
• Status: Expired due to Fees

• Current Assignee: National Starch and Chemical Investment Holding Corporation
• Original Assignee: National Starch and Chemical Investment Holding Corporation
• Inventors: Xiao, Yue
• Primary Examiner(s): Dawson, Robert
• Assistant Examiner(s): AYLWARD, DAVID E
• Application Number:
  US09/714,646
• Time in Patent Office: 376 Days
• Field of Search: 106/31.72, 106/31.92, 523/442, 523/457, 523/458, 523/459, 523/460
• US Class Current: 106/31.92
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H05K 1/095 for polymer thick films, i.e. having a permanent organic polymeric binder

Abstract

A thermoset conductive ink for use in through hole interconnections or similar electric and electronic applications to provide stable electrical connections. The conductive ink of this invention comprises a thermal curable resin system having an admixing of an epoxy resin, a cross-linking agent and a catalyst, an electrically conductive material such as silver, copper or silver-coated copper and an organic solvent.

Claims

1. A conductive ink for providing stable electrical connections comprising

(a) a thermal curable resin system comprising at least one epoxy resin, a cross-linking agent and a catalyst, wherein the cross-linking agent comprises methoxymethylmelamine;

(b) a particulated electrically conductive material; and

(c) an organic solvent.

2. The conductive ink of claim 1, wherein the conductive ink further comprises one of more flow additives, adhesion promoters, rheology modifiers, conductivity additives or mixtures thereof.

3. The conductive ink of claim 2, wherein

(a) the thermal resin system is present in an amount of about 1 to 20 weight percent of the at least one epoxy resin, about 0.2 to 15 weight percent of the methoxymethylmelamine and about 0.1 to 5 weight percent of the catalyst;

(b) the particulated electrically conductive material is present in an amount of about 50 to 90 weight percent;

(c) the organic solvent is present in an amount of about 5 to 50 weight percent; and

(d) the flow additives, adhesion promoter, rheology modifiers,conductivity additives or mixtures thereof are present in amount of about 0 to 5 weight percent;

for a total of 100 weight percent.

4. The conductive ink of claim 3, wherein the particulated electrically conductive material is silver, copper, silver-coated copper, silver-coated aluminum, coated mica, glass spheres or mixtures thereof.

5. The conductive ink of claim 4, wherein the catalyst is an acid.

6. The conductive ink of claim 5, wherein the at least one epoxy resin is a solid or liquid epoxy resin derived from bisphenol-A and epichlorohydrin.

7. The conductive ink of claim 5, wherein the acid is selected from the group consisting of mineral acids, p-toluene sulfonic acid, dinonylnaphthalene disulfonic acid, dodecyl benzene sulfonic acid, oxalic acid, maleic acid, hexamic acid, phosphoric acid, alkyl phosphate ester, phthalic acid, acrylic acid or mixtures thereof.

8. The conductive ink of claim 7, wherein the acid is dinonylnaphthalene disulfonic acid.

9. The conductive ink of claim 6, wherein the flow additives are selected from the group consisting of silicon polymers, ethyl acrylate/2-ethylhexyl acrylate copolymers, alkylol ammonium salt of acid phosphoric acid esters of ketoxime or mixtures thereof.

10. The conductive ink of claim 6, wherein the adhesion promotor is a silane.

11. The conductive ink of claim 10, wherein the adhesion promoter is mercaptosilane.

12. The conductive ink of claim 6, wherein the rheology modifer is thermoplastic resin.

13. The conductive ink of claim 12, wherein the rheology modifier is polyvinyl acetal.

14. The conductive ink of claim 6, wherein the conductivity additive is selected from the group consisting of hydroquinone, Vitamin E, metallic dryers, titanates, phosphoric acid, other acid catalysts, or mixtures thereof.

15. A conductive ink composition consisting essentially of:

(a) about 1 to 20 weight percent of at least one epoxy resin, about 0.2 to 15 weight percent of methoxymethylmelamine and about 0.1 to 5 weight percent of a catalyst;

(b) about 50 to 90 weight percent of a particulated electrically conductive material;

(c) about 5 to 50 weight percent of an organic solvent; and

(d) about 0 to 5 weight percent of flow additives, adhesion promoters, rheology modifiers or mixtures thereof.