Hot Melt Composition for ECU Sealing
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Solution Overview
Problem
Existing hot melt compositions for electronic control units (ECUs) are insufficient in removability and adhesion, and they tend to volatilize at high temperatures, leading to hygiene issues and sagging problems during application.
Innovation Solution
A hot melt composition comprising a thermoplastic block copolymer, a hydrocarbon-based liquid softening agent with an aniline point of 135° C or more, and a wax modified with carboxylic acid or carboxylic acid anhydride, which provides excellent adhesion, removability, and form maintaining properties without significant volatilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing hot melt compositions containing styrene-based block copolymer and various additives are used, then adhesion is improved, but removability is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters by specifying a thermoplastic block copolymer with 30-70 wt% styrene content and 30-70 wt% conjugated diene compound, along with specific additive combinations. This parameter optimization achieves a balance where the sealing material maintains strong adhesion during use but can be removed cleanly when needed, resolving the contradiction between adhesion strength and removability
Solution Approach 2:
The patent creates a composite sealing material by combining thermoplastic block copolymer with specific additives including phenyl compounds and antioxidants in controlled amounts. This composite formulation achieves both strong adhesion properties and improved removability, as the synergistic combination of components provides optimal bonding strength while maintaining clean removal capability
2Reliability
If hot melt composition contains large amount of antioxidant and various compounds, then adhesion and durability are improved, but components may volatilize at high temperature causing hygiene issues
Solution Approach 1:
The patent optimizes the concentration parameters of antioxidants and other additives to specific ranges that provide sufficient durability without excessive volatilization. By controlling the amounts of each component within specified limits, the formulation maintains reliability while minimizing harmful vapor emission at high temperatures
Solution Approach 2:
The patent employs antioxidants and additives that provide necessary durability during the service life of the ECU but are designed to minimize long-term volatilization. The composition achieves adequate protection against oxidation and degradation during use while reducing persistent harmful emissions, effectively balancing durability with reduced environmental and health impact
3Ease of manufacture
If hot melt composition is applied to ECU substrate, then sealing is achieved, but sagging from substrate may generate
Solution Approach 1:
The patent adjusts the melting point and viscosity parameters of the hot melt composition by selecting specific thermoplastic block copolymers and controlling the ratio of styrene to conjugated diene compounds. These parameter changes ensure the material has appropriate flow characteristics for complete substrate coverage during application, while maintaining sufficient shape stability to prevent sagging after solidification
Data Source
AI summary
An objective of the present invention is to provide a hot melt composition which has a high form maintaining property at a high temperature, is well-balanced between adhesion and removability to a substrate, hardly sags, has less volatile matter content and is excellent in hygiene. The present invention relates to a hot melt composition comprising: (A) a thermoplastic block copolymer which is a copolymer of a vinyl-based aromatic hydrocarbon and a conjugated diene compound, (B1) a hydrocarbon-based oil having an aniline point of 135° C. or more, and (C) a wax modified with a carboxylic acid and/or a carboxylic acid anhydride.