Epoxy Coating for Tin Solder Replacement

Solution Overview

Problem

The automotive industry faces challenges in repairing vehicle bodies due to the need for lead-free tin solder alternatives that are difficult to process and incompatible with new hardened steel types, which are sensitive to heat exposure and environmental regulations.

Innovation Solution

A curable two-part epoxy coating composition comprising a first part with diamine, amine epoxy hardener, and inorganic filler, and a second part with epoxy resin, epoxy-reactive flexibilizer, and inorganic filler, which can be mixed to form a curable composition for coating and curing at ambient temperature, providing mechanical strength and sandability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead-free tin solder materials are used, then environmental compliance is improved, but processability deteriorates significantly

Engineering Contradiction:

Improveenvironmental complianceVSAvoidprocessability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the lead component from traditional tin solder materials, replacing it with an epoxy-based composition that maintains the necessary functional properties while eliminating the harmful lead element, thus achieving environmental compliance without complete loss of processability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the fundamental material parameters from a metal-based solder (tin-lead alloy) to a polymer-based epoxy composition, altering the chemical composition, curing mechanism, and physical properties while maintaining the core function of filling and protecting steel sheet irregularities

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If traditional tin solder is used, then processability is improved, but environmental compliance deteriorates due to lead content

Engineering Contradiction:

ImproveprocessabilityVSAvoidenvironmental compliance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention extracts and removes the lead component from traditional tin solder materials, replacing it with an epoxy-based composition that maintains the necessary functional properties while eliminating the harmful lead element, thus achieving environmental compliance without complete loss of processability

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If heat exposure is applied for soldering, then joining is improved, but steel sheet properties deteriorate due to heat sensitivity

Engineering Contradiction:

Improvejoining strengthVSAvoidsteel sheet properties

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention replaces the thermal field (heat-based soldering process) with a chemical field (epoxy curing process), substituting the high-temperature joining mechanism with a room-temperature or low-temperature chemical bonding mechanism that achieves similar structural reinforcement without thermal damage

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental material parameters from a metal-based solder (tin-lead alloy) to a polymer-based epoxy composition, altering the chemical composition, curing mechanism, and physical properties while maintaining the core function of filling and protecting steel sheet irregularities

Inventive Principle:

Principle #35Parameter changes

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 epoxy coating composition offers fast curing times, excellent sandability, and corrosion resistance, making it suitable for repairing steel surfaces without compromising the properties of new steel types and adhering to environmental regulations.

Implementation Method 1

A curable two-part epoxy coating composition comprising a first part with diamine, amine epoxy hardener, and inorganic filler, and a second part with epoxy resin, epoxy-reactive flexibilizer, and inorganic filler, which can be mixed to form a curable composition for coating and curing at ambient temperature

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3473657B1Epoxy resin for tin solder replacement

Publication Date: 2020.04.15 3M INNOVATIVE PROPERTIES CO

AI summary

In one aspect of the present disclosure, there is provided a curable coating composition precursor, comprising (a) a first part (A) comprising: (i) at least one diamine in an amount of from 10 to 50 wt.-% based on the total weight of part (A) ; (ii) at least one amine epoxy hardener based on an phenolic lipid in an amount of from 10 to 50 wt.-% based on the total weight of part (A); (iii) at least one inorganic filler material in an amount of from 10 to 60 wt.-% based on the total amount of part (A); (b)a second part (B) comprising: (i) at least one first epoxy resin in an amount of from 15 to 60 wt.-% based on the total amount of part (B); (ii) at least one second epoxy-based resin distinct from the first epoxy resin in an amount of from 15 to 60 wt.-% based on the total amount of part (B); (iii) at least one epoxy-reactive flexibilizer in an amount of from 0.1 to 10 wt.-% based on the total amount of part (B); (iv) at least one inorganic filler material 5 to 50 wt.-%, preferably from 10 to 45 wt.-%, more preferably from 15 to 40 wt.-% b based on the total amount of part (B).