Curing-Agent-Free Polyester Adhesive for Solder Heat Resistance
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Solution Overview
Problem
Existing adhesive compositions, particularly those containing polyester-polyurethane and epoxy resin, fail to provide sufficient high heat resistance for lead-free solder and have inadequate pot life properties due to the inclusion of curing agents.
Innovation Solution
A polyester resin composition with no curing agent, achieving self-curing through a specific amount of tetrahydrofuran-insoluble matter, balanced curing properties, and excellent adhesiveness by controlling catalyst amounts, ensuring high solder heat resistance and improved pot life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a curing agent is included in the adhesive composition to achieve curing, then adhesiveness is improved, but pot life property deteriorates
Solution Approach 1:
The invention extracts and removes the curing agent from the adhesive composition, achieving self-curing through the polyester resin's inherent properties. This eliminates the harmful effect of curing agents on pot life while maintaining curing capability through thermal treatment during manufacturing processes.
Solution Approach 2:
The polyester resin is designed to self-cure without external curing agents by utilizing its own chemical structure and reacting to heat treatment. The resin contains functional groups that enable crosslinking and curing when exposed to elevated temperatures during manufacturing, eliminating the need for separate curing agents.
2Ease of manufacture
If conventional adhesive compositions are used to achieve basic adhesiveness, then processability is maintained, but solder heat resistance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive by using specific polyester resins with controlled molecular weight, functional group content, and purity. These parameter changes enable the adhesive to withstand soldering temperatures (typically 260-280°C) while maintaining processability through standard manufacturing techniques.
3Temperature
If curing agents are added to achieve crosslinking, then heat resistance is improved, but the composition generates harmful outgas, deteriorating environmental compatibility
Solution Approach 1:
The invention converts the potential harm of curing agents into a benefit by eliminating them entirely and using the polyester resin's own structure to provide heat resistance. The self-curing mechanism produces minimal outgas compared to conventional curing agents, transforming the harmful emissions issue into an environmentally friendly solution.
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 adhesive resin composition exhibits excellent adhesiveness to various base materials, high solder heat resistance, and good pot life properties without the need for curing agents, making it suitable for lead-free solder applications.
Implementation Method 1
a polyester resin composition exhibiting a certain amount or more of tetrahydrofuran-insoluble matter when having undergone a prescribed heating treatment enables curing of a polyester resin by itself
Implementation Method 2
heating treatment at 200° C. for 1 hour
Data Source
AI summary
An adhesive resin composition according to the present invention is characterized by containing a polyester resin (A) and satisfying: (i) The adhesive resin composition contains substantially no curing agent; and (ii) The adhesive resin composition exhibits an amount of tetrahydrofuran-insoluble matter of 10 mass % or more when having undergone a heating treatment at 200° C. for 1 hour. The adhesive resin composition according to the present invention, even with use of substantially no curing agent, has good pot life property, and has excellent solder heat resistance and adhesiveness to various base materials. The present invention also provides a laminate or an adhesive sheet including an adhesive layer made from the adhesive resin composition, a printed-wiring board or a packing material comprising the laminate as a constituent element, and a laminated film for decorating three-dimensional molded article or a film for laminating metal can comprising the adhesive sheet as a constituent element.