Solder Paste Flux Using Acetylated Activators for Residue Color Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solder pastes using amine or amino acid compounds as activators face issues with darkening of the residual activator due to reflow, leading to erroneous quality inspections and potential increases in viscosity during storage.
Innovation Solution
Incorporating an amine compound or an amino acid compound with acetylated amino groups, such as N-acetylimidazole, N-acetylphthalimide, tetraacetylethylenediamine, N-acetylglycine, N-acetylleucine, or N-acetylphenylglycine, as activators in the flux to enhance heat resistance and reduce polarity, thereby improving wettability and preventing darkening of the residual activator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an amine compound or amino acid compound is used as an activator in the flux, then high active force is achieved for removing oxide films, but the residual activator darkens during reflow causing erroneous quality inspection
Solution Approach 1:
The patent changes the chemical structure of the activator by introducing acetylated amino groups (such as N-acetylimidazole, N-acetylphthalimide, tetraacetylethylenediamine, N-acetylglycine, N-acetylleucine, or N-acetylphenylglycine) to modify the thermal stability and oxidation resistance of the activator, thereby preventing darkening during reflow while maintaining cleaning effectiveness
Solution Approach 2:
The flux is formulated as a composite containing multiple components including the acetylated activator (0.1-5 wt%), resin component (30-70 wt%), solvent (10-50 wt%), and other additives, creating a synergistic system that maintains both cleaning power and color stability
2Reliability
If an amine compound is used as an activator, then high reactivity with metals is achieved for oxide removal, but the viscosity of the solder paste increases during storage due to reaction with solder powder
Solution Approach 1:
The acetylation of the amino group modifies the chemical parameters of the activator, reducing its reactivity with metals during storage while preserving its ability to remove oxide films during soldering, thus preventing unwanted viscosity changes
Solution Approach 2:
The acetylated amino groups are pre-modified to have reduced reactivity, allowing the solder paste to remain stable during storage while still enabling effective oxide removal when heated during the soldering process
3Object-generated harmful factors
If the content of the activator in the flux is limited, then darkening of the residual color is suppressed, but the effects of the activator are reduced
Solution Approach 1:
By changing the chemical structure to acetylated amino groups, the patent achieves better color stability at comparable or even higher activator concentrations (0.1-5 wt%), resolving the trade-off between effectiveness and color stability
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 use of acetylated amino group-containing activators in the solder paste flux ensures good wettability during reflow and suppresses the darkening of the residual activator, thereby enhancing the reliability of quality inspections and maintaining the paste's viscosity stability.
Implementation Method 1
Incorporating an amine compound or an amino acid compound with acetylated amino groups, such as N-acetylimidazole, N-acetylphthalimide, tetraacetylethylenediamine, N-acetylglycine, N-acetylleucine, or N-acetylphenylglycine, as activators in the flux to enhance heat resistance and reduce polarity, thereby improving wettability
Implementation Method 2
the activator is oxidized to be burned due to reflow, as a result of which the hue of the residue of the activator becomes dark (the residual color is concentrated)
Data Source
AI summary
Provided is a flux that contains at least one of an amine compound containing at least one acetylated amino group and an amino acid compound containing at least one acetylated amino group, as an activator.