Soldering Resin Composition for Stable Wetting and Spreading

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Solution Overview

Problem

Conventional soldering fluxes with dimer acid as an activator face variability in wetting and spreading properties and reliability due to differences in carbon atoms, degree of unsaturation, and heat history, leading to inconsistent soldering finishes and processability issues.

Innovation Solution

A resin composition incorporating 1-40 wt% of specific reaction products such as dimer acid, trimer acid, hydrogenated dimer acid, or hydrogenated trimer acid derived from oleic and linoleic acids, combined with 30-99 wt% rosin, along with optional additives like organic acids, amines, and solvents, to enhance wetting, spreading, and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional dimer acid is used as an activator in flux, then the flux can chemically remove metal oxides, but the wetting and spreading properties vary significantly due to differences in carbon atoms, degree of unsaturation, and structure

Engineering Contradiction:
Improvewetting and spreading propertiesVSAvoidconsistency of dimer acid structure
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent specifies precise compositional parameters for the dimer acid (reaction product of oleic acid and linoleic acid) including carbon atom count, degree of unsaturation, and structural characteristics. By controlling these parameters within defined ranges, the invention achieves consistent wetting and spreading properties while maintaining structural stability across different heat histories.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flux composition combines dimer acid with specific ratios of other components (rosin, organic acids, amines, and additives) to create a composite material system. This composite approach compensates for structural variations in dimer acid and ensures reliable soldering performance across different production batches and heat treatment conditions.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the same amount of organic acid is added in formulation of the flux, then the flux composition remains consistent, but the specific resistance of aqueous solution and corrosiveness are significantly changed

Engineering Contradiction:
Improveflux formulation consistencyVSAvoidspecific resistance and corrosiveness
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent establishes specific concentration ranges for organic acids and other components in the flux formulation. By controlling the amounts of organic acids, amines, and additives within defined parameters, the invention maintains both formulation consistency and reliable electrical properties (specific resistance) while controlling corrosiveness to acceptable levels.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention incorporates measurements of specific resistance and corrosiveness as feedback parameters to optimize and control the flux composition. By monitoring these properties and adjusting the formulation accordingly, the patent ensures that consistent composition leads to reliable performance characteristics.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If dimer acid with varying structures is used, then different flux compositions can be formulated, but the soldering finish is completely different due to heat history variations

Engineering Contradiction:
Improveflux composition variabilityVSAvoidsoldering finish consistency
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent defines specific structural parameters for the dimer acid (carbon atom number, unsaturation degree, molecular weight) and controls these within defined ranges. This parameter control ensures that despite natural variations in dimer acid production, the soldering finish remains consistent across different heat histories and production batches.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention focuses on controlling the local chemical structure of the dimer acid molecules (specific functional groups, chain length, unsaturation positions) that directly affect soldering performance. By ensuring uniformity in these critical local structures while allowing some variability in less critical aspects, the patent achieves consistent soldering finishes.

Inventive Principle:
Principle #3Local quality

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 resin composition achieves improved wetting and spreading properties, maintains high specific resistance of aqueous solutions for reduced corrosion, and ensures stable processability across various heat histories, making it suitable for resin flux cored solder, flux coated solder, and liquid flux applications.

Implementation Method 1

a flux used for soldering chemically removes a metal oxide present on a solder and the metal surfaces of a joining object to be soldered

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

improved wetting and spreading properties

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentUS11292089B2Resin composition for soldering, resin flux cored solder, flux coated solder, and liquid flux
Publication Date: 2022.04.05 SENJU METAL IND CO LTD

AI summary

A resin composition for soldiering is provided. The resin composition includes 1 wt % or more and 40 wt % or less of a dimer acid, a trimer acid, or a combination thereof, 30 wt % or more and 99 wt % or less of a rosin, and 0 wt % or more and 13 wt % or less of a solvent. The dimer acid is selected from a dimer acid that is a reaction product of oleic acid and linoleic acid, a hydrogenated dimer acid obtained by adding hydrogen to a dimer acid that is a reaction product of oleic acid and linoleic acid, and a combination thereof. The trimer acid is selected from a trimer acid that is a reaction product of oleic acid and linoleic acid, a hydrogenated trimer acid obtained by adding hydrogen to a trimer acid that is a reaction product of oleic acid and linoleic acid, and a combination thereof.