Pb free Ag paste composition for PDP address electrode

• US 20060011895A1
• Filed: 06/01/2005
• Published: 01/19/2006
• Est. Priority Date: 06/01/2004
• Status: Active Grant

• Current Assignee: Dongjin Semichem Co., Ltd.
• Original Assignee: Dongjin Semichem Co., Ltd.
• Inventors: Park, Chan-seok, Chung, Byung-joo, Paek, Sin-hye, Park, Seong-mo
• Granted Patent: US 7,300,606 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: H01B 1/16 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01J 2211/225 Material of electrodes
• CPC Class Codes: H01J 9/02 Manufacture of electrodes or electrode systems

Abstract

The present invention provides a Pb free Ag paste composition for a PDP address electrode comprising a) 60 to 90% by weight of an Ag powder; b) 1 to 10% by weight of a Pb free inorganic binder; c) 0.001 to 1% by weight of an inorganic thickener; and d) 5 to 38% by weight of an alkali-soluble, negative photoresist composition for fine conductive powder dispersion. The Pb free Ag paste composition according to the invention i) is environment-friendly by using a Pb free inorganic binder, ii) is suitable for the fabrication of fine electrodes by using the prior electrode formation processes, iii) can apply the formed pattern to low temperature sintering processes of not higher than 600° C., iv) does not use a surfactant and stabilizer and has excellent printing, leveling and sintering performances by using an inorganic thickener and conductive Ag powder, and v) enables sintering to be carried out at a sintering target temperature without binder burning off zone.

Claims

1. A Pb free Ag paste composition for a PDP address electrode comprising:

a) 60 to 90% by weight of an Ag powder;

b) 1 to 10% by weight of a Pb free inorganic binder;

c) 0.001 to 1% by weight of an inorganic thickener; and

d) 5 to 38% by weight of an alkali-soluble, negative photoresist composition for fine conductive powder dispersion.

2. The Pb free Ag paste composition of claim 1 wherein the Ag powder has a particle shape of sphere.

3. The Pb free Ag paste composition of claim 1 wherein the Ag powder has an average diameter (D₅₀) of 0.5 to 3 μ

m and a maximum diameter (D_max) of 3 to 5 μ

m.

4. The Pb free Ag paste composition of claim 1 wherein the purity of the Ag powder is not less than 96%.

5. The Pb free Ag paste composition of claim 1 wherein the tap density of the Ag powder is 4.3 to 5.0 g/cm³.

6. The Pb free Ag paste composition of claim 1 wherein the Pb free inorganic binder is selected from the group consisting of Bi₂O₃, SiO₂, B₂O₃, ZrO₂, Al₂O₃ and combination thereof and does not contain Na₂O, K₂O, Li₂O or PbO.

7. The Pb free Ag paste composition of claim 1 wherein the Pb free inorganic binder has a glass transition temperature of 350 to 500°

C. and a glass softening temperature of 400 to 500°

C.

8. The Pb free Ag paste composition of claim 1 wherein the Pb free inorganic binder has an average diameter (D₅₀) of 0.5 to 3 μ

m and a maximum diameter (D_max) of 3 to 5 μ

m.

9. The Pb free Ag paste composition of claim 1 wherein the Pb free inorganic binder is dried at a temperature between 80 and 300°

C., which is 100°

C. lower than the glass transition temperature of the inorganic binder.

10. The Pb free Ag paste composition of claim 1 wherein the inorganic thickener is selected from the group consisting of silica, kaolin, alumina, mica and combination thereof.

11. The Pb free Ag paste composition of claim 1 wherein the alkali-soluble, negative photoresist composition for fine conductive powder dispersion comprises

a) 5 to 50% by weight of an acrylate copolymer for photoresist represented by formula 1:

wherein R₁ is a hydrogen, phenyl group, phenyl group substituted with nitro group, phenyl group substituted with halogen, benzyl group substituted with nitro group, C1 to C10 alkyl group which may contain an unsaturated group or unsaturated carbon, or C1 to C10 alkyl group substituted with hydroxy group;

R₂ is an alkyl group selected from the group consisting of ethylhexyl group, isobutyl group, tert-butyl group and octyl group, 3-methoxy butyl group, or methoxy propylene glycol group;

R₃ is a hydrogen or alkyl group;

R₄ is a hydrogen or alkyl group; and

n₁ and n₂ are an integer of 1 to 120, or formula 2;

wherein R₅ is a hydrogen or carboxyl group;

R₆ is a phenyl group, carboxyl group, or —

OCOCH₃ group;

R₇ is a hydrogen or —

CH₂COOH group; and

R₂, R₄, n₁, and n₂ are the same as defined in formula 1;

b) 5 to 40% by weight of a photopolymerizable monomer;

c) 5 to 20% by weight of a photopolymerization initiator;

d) 5 to 10% by weight of a defoamer;

e) 4.5 to 30% by weight of a leveling agent;

f) 0.5 to 10% by weight of a plasticizer; and

g) 30 to 60% by weight of a solvent.

12. The Pb free Ag paste composition of claim 1 wherein the alkali-soluble, negative photoresist composition for fine conductive powder dispersion further comprises a dispersant in an amount not more than 3% by weight.

13. The Pb free Ag paste composition of claim 11 wherein the photopolymerizable monomer is selected from the group consisting of butanediol diacrylate, triethyleneglycol diacrylate, 1,4-butanediol diacrylate, 1,3-butyleneglycol diacrylate, 1,6-hexanediol diacrylate, ethyleneglycol diacrylate, diethyleneglycol diacrylate, trimethylpropane triacrylate (TMPTA), tripropyleneglycol diacrylate (TPGDA), tetraethyleneglycol diacrylate (TTEGDA), trimethylpropane ethoxytriacrylate (TMPEOTA), polyethyleneglycol diacrylate, dipentaerythritolkisaacrylate, dipentaerythritol hydroxypentacrylate, glycerol diacrylate, trimethyolpropane trimethacrylate, pentaerythritol trimetharcylate, pentaerythritol dimethacrylate, sorbitol trimethacrylate, bisphenol A diacrylate derivative, trimethylolpropane triacrylate, dipentaerythritol polyacrylate, and combination thereof.

14. The Pb free Ag paste composition of claim 11 wherein the photopolymerization initiator is selected from the group consisting of 2,4-bistrichloromethyl-6-p-methoxystyryl-s-triazine, 2-p-methoxystyryl-4,6-bistrichloromethyl-s-triazine, 2,4-trichloromethyl-6-triazine, 2,4-trichloromethyl-4-methylnaphthyl-6-triazine, benzophenone, p-(diethylamino)benzophenone, 2,2-dichloro-4-phenoxyacetophenone, 2,2′

-diethoxyacetophenone, 2,2′

-dibutoxyacetophenone, 2-hydroxy-2-methylproliophenone, p-t-butyltrichloroacetophenone, p-t-butyldichloroacetophenone, benzyldimethylketal, 4,4′

-ethylaminobenzophenone, 2-methyl-1-4-methylthiophenyl-2-4-morpholinyl-1-propanone, 2-benzyl-2-dimethylamino-1-4-4′

morpholinylphenyl-1-butanone, 2,4,6-trimethyl benzoyl, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isobutylthioxanthone, 2-dodecylthioxanthone, isopropyl-9H-thioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone-2,2′

-bis-2-chlorophenyl-4,5,4′

,5′

-tetraphenyl-2′

-1,2 ′

-biimidazole, and combination thereof.

15. The Pb free Ag paste composition of claim 11 wherein the leveling agent is an anionic copolymer or aralkyl modified polymethylalkylsiloxane compound, and the defoamer is selected from the group consisting of polyester modified polymethylalkylsiloxane, polysiloxane, non-silicone polymer compound, modified urea solution, polyester modified dimethylpolysiloxane, polyester modified dimethylpolysiloxane copolymer, and combination thereof.

16. The Pb free Ag paste composition of claim 11 wherein the plasticizer is selected from the group consisting of paraffin oil, dioctylphthalate, dibutoxyethyl phthalate, tricrysylphosphate, dioctylcebacate, triphenylphosphate, chlorinated biphenyl, dihexylphthalate, hydro terphenyl, dibutylphthalate, dipropylphthalate, diethylphthalate, dimethylphthalate, santicizer, glycerin, and combination thereof.

17. The Pb free Ag paste composition of claim 11 wherein the solvent is selected from the group consisting of carbitolacetate, gammabutyrolactone, diethyleneglycol monobutylether, diethyleneglycol monobutyletheracetate, trimethylpentanediol monoisobutyrate, dipropyleneglycol monoethylether, methylcelosolv, ethylcelosolv, butylcelosolv, methylethylketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, and combination thereof.

18. The Pb free Ag paste composition of claim 1 wherein the Ag paste composition has a viscosity of 3000 to 60000 cP.

19. A PDP address electrode prepared using the Pb free Ag paste composition according to claim 1.