Manufacturing method of metal paste

• US 20050267243A1
• Filed: 05/26/2005
• Published: 12/01/2005
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited)
• Original Assignee: Dowa Mining Company Limited (DOWA Holdings Company Limited)
• Inventors: Kohayashi, Shuichi, Amasaki, Kazuyoshi, Omoto, Yoshikazu
• Granted Patent: US 7,434,981 B2
• Time in Patent Office: Days
• US Class Current: 524/439
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/22 Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
• CPC Class Codes: C09C 1/646 concomitant with mechanical comminution, shaping or abrasion of the particles

Abstract

A metal paste, in which a filler mainly composed of metal is mixed with good dispersibility, is manufactured with good productivity at a low cost without generating a foil of the metal. A paste-like material (referred to as a paste material hereafter) containing a metal filler is fed into a gap between a pair of rotating whetstones 11 and 12 which are relatively rotated while facing with each other having a specified gap therebetween, to pass and discharge therein. The paste material is thus kneaded and dispersed. In addition, the paste material is kneaded and dispersed by suppressing the generation of a metal foil, adjusting the gap to a specified interval dg and feeding the paste material into the interval while applying thereon a predetermined positive pressure and/or negative pressure.

Claims

1-5. -5. (canceled)

6. A manufacturing method of a metal paste in which a paste-like material (referred to as a paste material hereafter) containing a metal filler is fed and kneaded and dispersed in a gap of whetstones which are relatively rotated while facing with each other having a prescribed gap therebetween so that the metal filler is mixed and dispersed in the paste material, wherein the paste material is kneaded and dispersed while keeping the temperature of the paste material larger than the temperature of a viscosity at which the paste material is capable of passing through the gap of a pair of whetstones.

7. The manufacturing method of the metal paste according to claim 6, wherein the metal filler is mixed and dispersed in the paste material by adjusting a gap interval dg of the whetstones in a range from (⅕

) dm to 2 dm, when a maximum particle diameter of the metal filler in the paste material is dm.

8. The manufacturing method of the metal paste according to claim 6, wherein temperature of the paste material is kept to the temperature within a range from 10 to 40 (Pa·

s) at a measured value by a rotational viscometer rotating at a shear rate of 2 s<sup>−

1</sup>, and from 2 to 20 (Pa·

s) at the measured value of the rotational viscometer rotating at the shear rate of 10 s<sup>−

1</sup>.

9. The manufacturing method of the metal paste according to claim 6, wherein the temperature of the paste material is kept in a range from 40°

C. to 80°

C.

10. The manufacturing method of the metal paste according to claim 6, wherein the paste material is kneaded and dispersed, while applying a pressure difference of 0.01 MPa to 0.5 MPa between the paste material fed into the whetstones and the paste material fed out from the whetstones.

11. The manufacturing method of the metal paste according to claim 7, wherein temperature of the paste material is kept to the temperature within a range from 10 to 40 (Pa·

s) at a measured value by a rotational viscometer rotating at a shear rate of 2 s<sup>−

1</sup>, and from 2 to 20 (Pa·

s) at the measured value of the rotational viscometer rotating at the shear rate of 10 s<sup>−

1</sup>.

12. The manufacturing method of the metal paste according to claim 7, wherein the temperature of the paste material is kept in a range from 40°

C. to 80°

C.

13. The manufacturing method of the metal paste according to claim 8, wherein the temperature of the paste material is kept in a range from 40°

C. to 80°

C.

14. The manufacturing method of the metal paste according to claim 7, wherein the paste material is kneaded and dispersed, while applying a pressure difference of 0.01 MPa to 0.5 MPa between the paste material fed into the whetstones and the paste material fed out from the whetstones.

15. The manufacturing method of the metal paste according to claim 8, wherein the paste material is kneaded and dispersed, while applying a pressure difference of 0.01 MPa to 0.5 MPa between the paste material fed into the whetstones and the paste material fed out from the whetstones.

16. The manufacturing method of the metal paste according to claim 9, wherein the paste material is kneaded and dispersed, while applying a pressure difference of 0.01 MPa to 0.5 MPa between the paste material fed into the whetstones and the paste material fed out from the whetstones.