Conductive Paste Fluidity via Solvent Delta-Delta Ratio
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Solution Overview
Problem
The use of conductive paste containing cellulose acetate butyrate resin and Ni powder in semiconductor electrodes often results in printing defects due to decreased fluidity, caused by insufficient adsorption of the resin onto the Ni powder, leading to blurring and incomplete coating films.
Innovation Solution
A conductive paste is formulated with Ni powder of 30-400 nm primary particle size, cellulose acetate butyrate as the binder resin, and a specific ratio of organic solvents A and B, where A has a Δδ value of 11.5 or less and B from 11.5 to 25.0 with the binder, ensuring appropriate fluidity and preventing sedimentation of Ni particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive paste containing cellulose acetate butyrate resin and Ni powder is used, then electrical conductivity and flexibility are improved, but printing quality deteriorates due to decreased fluidity and print blurring
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive paste by introducing a specific solvent system comprising a first solvent (Δδ ≤ 11.5) and a second solvent (11.5 < Δδ ≤ 25.0) in controlled ratios. This parameter modification adjusts the paste's fluidity and adsorption characteristics, enabling it to maintain both good electrical conductivity and printing quality without print blurring
Solution Approach 2:
The patent creates a composite solvent system combining two different solvents with specific solubility parameter ranges. The first solvent (Δδ ≤ 11.5) provides good dissolution of cellulose acetate butyrate resin, while the second solvent (11.5 < Δδ ≤ 25.0) modulates the paste's fluidity and promotes proper adsorption onto Ni powder, achieving a balance between conductivity and printability
2Duration of action of stationary object
If cellulose acetate butyrate resin is used as binder, then flexibility and long life are improved, but paste fluidity decreases causing insufficient adsorption onto Ni powder
Solution Approach 1:
The patent modifies the paste's physical and chemical parameters by selecting solvents with specific solubility parameters. The first solvent (Δδ ≤ 11.5) ensures adequate dissolution of cellulose acetate butyrate resin for flexibility, while the second solvent (11.5 < Δδ ≤ 25.0) in controlled amounts (5-50 wt% of total solvent) adjusts the paste's fluidity and adsorption behavior, preventing both excessive viscosity and insufficient adsorption
3Stability of the object's composition
If organic solvent with low Δδ value is used to dissolve binder resin, then resin dissolution is improved, but paste fluidity decreases leading to printing defects
Solution Approach 1:
The patent employs a composite solvent system where the first solvent (Δδ ≤ 11.5) provides excellent resin dissolution for composition stability, while the second solvent (11.5 < Δδ ≤ 25.0) is added in specific proportions (5-50 wt% of total solvent) to counterbalance the excessive viscosity caused by the first solvent alone. This composite approach prevents printing defects while maintaining adequate resin dissolution
Solution Approach 2:
The patent adjusts the solvent composition parameters by controlling the ratio of first to second solvent. The second solvent with higher Δδ value (11.5 < Δδ ≤ 25.0) modifies the overall solvent system's interaction with the binder resin and Ni powder, optimizing paste fluidity and adsorption characteristics to eliminate printing defects while preserving resin dissolution
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution maintains the paste's fluidity, preventing printing defects and ensuring excellent print characteristics, as demonstrated by the formation of smooth and effective conductor patterns in ceramic electronic components.
Implementation Method 1
organic solvent A is a solvent having a Δδ value of 11.5 or less with the cellulose acetate butyrate
Implementation Method 2
a ratio of the organic solvent B relative to a total of the organic solvent A and the organic solvent B is 5.0 to 40.0 wt %
Data Source
AI summary
A conductive paste obtained by adding an organic solvent B to a vehicle containing a Ni powder, a binder resin component, and an organic solvent A. The Ni powder has an average primary particle size of 30 to 400 nm. The binder resin component is cellulose acetate butyrate. Organic solvent A is a solvent having a Δδ value of 11.5 or less with the cellulose acetate butyrate. Organic solvent B is a solvent having a Δδ value from 11.5 to 25.0 with the cellulose acetate butyrate. A ratio of the organic solvent B relative to a total of the organic solvent A and the organic solvent B is 5.0 to 40.0 wt %.