Hot Melt Adhesive Composition for Heat-Stable Sealing and Disassembly
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Solution Overview
Problem
Existing hot melt adhesive compositions fail to prevent deformation at high temperatures and have poor disassembly properties, especially in LED lighting appliances, leading to difficulties in maintaining form and ease of removal over time.
Innovation Solution
A hot melt composition comprising a thermoplastic block copolymer of vinyl-based aromatic hydrocarbon and conjugated diene compounds, combined with a hydrocarbon-based liquid softening agent having an aniline point of 135°C or more, which enhances adhesive strength and ease of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional moisture-curable hot melt adhesives are used for sealing lighting appliances, then sealing property is improved, but disassembly difficulty increases and deformation resistance at high temperature deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using specific block copolymer structures (styrene-ethylene/propylene-styrene and styrene-ethylene-butylene-styrene) with controlled molecular weights and ratios. This parameter optimization allows the adhesive to maintain sealing reliability while improving disassembly property, resolving the contradiction between strong adhesion and ease of removal.
Solution Approach 2:
The patent employs a composite material system combining multiple block copolymers (SEPS and SEBS) with specific ratios. This composite approach leverages the complementary properties of different copolymers to achieve both strong sealing performance and improved disassembly characteristics, overcoming the limitations of single-component adhesives.
2Ease of repair
If styrene-based block copolymer hot melt adhesive is used for sealing, then disassembly property is improved, but deformation resistance at high temperature deteriorates
Solution Approach 1:
The patent optimizes the molecular weight parameters and compositional ratios of the block copolymers. By carefully controlling these parameters, the adhesive achieves a balance between disassembly ease and high-temperature deformation resistance, with the glass transition temperature and melt viscosity optimized for both requirements.
Solution Approach 2:
The patent introduces local quality variations through the use of different block copolymer segments with distinct properties. The styrene blocks provide structural integrity and heat resistance, while the ethylene/propylene or ethylene/butylene blocks provide flexibility and disassembly ease, creating a material with spatially differentiated functional properties.
3Reliability
If hot melt adhesive with high adhesive strength is used for long-term sealing, then sealing reliability is improved, but disassembly difficulty increases over time
Solution Approach 1:
The patent designs the adhesive to maintain continuous useful action during service (strong sealing) while enabling discontinuous action for disassembly. The block copolymer structure provides continuous adhesion during operation but allows controlled removal when needed, even after long-term use and aging, by leveraging the thermoplastic nature and specific molecular architecture.
Data Source
AI summary
An objective of the present invention is to provide a hot melt composition having a high form maintaining property at a high temperature and being in excellent adhesion to a substrate and in disassembly. The present invention relates to a hot melt composition comprising: (A1) a styrene-ethylene-ethylene/propylene-styrene block copolymer (SEEPS) and (B1) a hydrocarbon-based oil having an aniline point of 135°C or more.