Highly crystalline silver powder and production method of highly crystalline silver powder

Inactive Publication Date: 2009-05-07
MITSUI MINING & SMELTING CO LTD
View PDF1 Cites 20 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0029]The production method of the highly crystalline silver powder of the present invention is suitable for the production of the highly crystalline silver powder whose particles have fine diameter to large diameter by using a water-soluble organic acid together with a reducing agent. In particular, the process is hard to be affected by process changes such as temperature variation, concentration variation at the time of the reductive reaction and the process enables production of the highly crystalline silver powder at a high yield.
[0030]The highly crystalline silver powder shows powder characteristics as followings. Volume accumulated average particle diameter D50 of 0.1 μm to 5.0 μm when measured by laser diffraction sca

Problems solved by technology

L ascorbic acid, which is used as a reducing agent in the production method disclosed in above Patent Document 4 relating to high crystalline silver powder, is expensive and may result increasing of the product price.
However, when fine silver powder particles having a particle diameter less than 2 μm with a crystal diameter of more than 400 Å are aimed, lack of process stability of the production method may result wide variation in the crystal diameter.
Further, it has been confirmed in many case that the fine particles cannot satisfy thermal shrinkage resistance because shrinkage factor after sintering of the fine silver powder particles less than 2 μm is too large.
They are strongly odorous subst

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0053]Preparation of the first aqueous solution: The solution was prepared by mixing 1.0 g of gelatin, 50 g of silver nitrate and 26.4 g of nitric acid to 250 g of pure water and elevating the temperature of the mixture to 50° C. with stirring to finish dissolving.

[0054]Preparation of the second aqueous solution: The solution was prepared as a solution in which 26.4 g of L-sorbic acid as a reducing agent and 4.2 g of DL-malic acid as a water-soluble organic acid were dissolved in 250 g of pure water.

[0055]Reductive deposition of the highly crystalline silver powder: The second aqueous solution was slowly added to the first aqueous solution at a solution temperature of 50° C. for 30 minutes. After finishing addition of the second aqueous solution to mix with the first aqueous solution, stirring was kept for five minutes to grow deposited silver particles.

[0056]Collection by filtration of the highly crystalline silver powder: After finishing the five-minute stirring, the mixture was k...

example 2

[0057]Preparation of the first aqueous solution: Same as in Example 1 and description is omitted to avoid redundancy.

[0058]Preparation of the second aqueous solution: The solution was prepared as a solution in which 26.4 g of L-sorbic acid as a reducing agent and 3.6 g of citric acid as a water-soluble organic acid were dissolved in 250 g of pure water.

[0059]Reductive deposition of the highly crystalline silver powder: The second aqueous solution was slowly added to the first aqueous solution at 50° C. for 30 minutes. After finishing addition of the second aqueous solution to mix with the first aqueous solution, stirring was kept for five minutes to grow deposited silver particles.

[0060]Collection by filtration of the highly crystalline silver powder: After finishing the five-minute stirring, the mixture was kept still to settle generated silver powder, supernatant liquid was discarded and filtration and rinsing were performed by popular methods, and the highly crystalline silver po...

example 3

[0061]Preparation of the first aqueous solution: The solution was prepared by mixing 3.3 g of gelatin, 55 g of silver nitrate and 27 g of nitric acid to 550 g of pure water and elevating the temperature of the mixture to 50° C. with stirring to finish dissolving.

[0062]Preparation of the second aqueous solution: The solution was prepared as a solution in which 28.1 g of L-sorbic acid as a reducing agent and 4.47 g of DL-malic acid as a water-soluble organic acid were dissolved in 250 g of pure water.

[0063]Reductive deposition of the highly crystalline silver powder: The second aqueous solution was slowly added to the above first aqueous solution at 50° C. for 30 minutes. After finishing addition of the second aqueous solution to mix with the first aqueous solution, stirring was kept for five minutes to grow deposited silver particles.

[0064]Collection by filtration of the highly crystalline silver powder: After finishing the five-minute stirring, the mixture was kept still to settle g...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Lengthaaaaaaaaaa
Lengthaaaaaaaaaa
Concentrationaaaaaaaaaa
Login to view more

Abstract

Object of the present invention is to provide a production method of a highly crystalline silver powder containing powder particles in fine particle region and having a good particle size distribution as well as the highly crystalline silver powder obtained by the production method. In order to achieve the object, the present invention adopts a production method characterized in that the method comprises preparation of a first aqueous solution in which gelatin, silver nitrate and nitric acid are dissolved in water, preparation of a second aqueous solution in which L-sorbic acid and/or ascorbic acid and a water-soluble organic acid are dissolved, adding of the second aqueous solution slowly to mix with the first aqueous solution, stirring of the mixture to grow the silver particles after finishing the mixing, keeping of the mixture still to settle the silver particles, discarding of the supernatant, filtration and rinsing to obtain the highly crystalline silver powder.

Description

TECHNICAL FIELD[0001]The present invention relates to highly crystalline silver powder among the silver powders and production method of the highly crystalline silver powder.BACKGROUND ART[0002]Conventionally, highly crystalline silver powder (which has a large crystal diameter) has been widely used for processing into silver ink and silver paste for the reason that it is excellent in thermal shrinkage resistance at the time of sintering. For example, it has been used in wiring circuit of printed wiring board, via hole filling, adhesive for mounting devices and the similar applications in which a silver powder is mixed and cured with various kinds of resin components as well as applications in which a silver powder is sintered at relatively high temperatures such as circuit formation by co-sintering with a ceramic substrate. Silver powder excellent in thermal shrinkage resistance at the time of sintering has been demanded from the point of view for improving accuracy of shape as a c...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C22C5/06
CPCB22F9/24B22F1/0044B22F1/07B22F1/00
Inventor FUJIMOTO, TAKUSASAKI, TAKUYAYOSHIMARU, KATSUHIKO
Owner MITSUI MINING & SMELTING CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap