Hot-Melt Composition Balancing Workability and Hot-Flow Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hot-melt compositions for bonding automobile lighting fixtures suffer from poor workability, hot flow resistance, balance between adhesion and detachability, volatility resistance, and hot creep resistance.
Innovation Solution
A hot-melt composition comprising styrene-based thermoplastic elastomers with specific molecular weights and styrene content, olefin-based thermoplastic elastomers, aromatic petroleum resin, terpene phenol resin, and amorphous polyalphaolefin, along with high and low molecular weight paraffin oils, to enhance performance in these areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a styrene-based thermoplastic elastomer with weight average molecular weight of 300,000 or more is used, then hot flow resistance is improved, but workability deteriorates due to high viscosity
Solution Approach 1:
The patent uses a composite system of three different thermoplastic elastomers (styrene-based high molecular weight, styrene-based low styrene content, and olefin-based) to combine the hot flow resistance of high molecular weight materials with the processability of lower viscosity materials, achieving both improved hot flow resistance and maintained workability
Solution Approach 2:
The patent changes multiple parameters simultaneously: using styrene-based thermoplastic elastomer (1a) with weight average molecular weight of 300,000 or more for hot flow resistance, while incorporating styrene-based thermoplastic elastomer (1b) with styrene content of no greater than 20% by mass to reduce viscosity and improve workability, and olefin-based thermoplastic elastomer (1c) to balance both properties
2Strength
If strong adhesion is achieved through high molecular weight elastomers, then bonding strength is improved, but detachability deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and composition parameters of the thermoplastic elastomers to achieve a balance where the cured product provides sufficient adhesion strength for bonding while maintaining detachability for interface peeling and reworkability, specifically using styrene-based thermoplastic elastomer (1a) with weight average molecular weight of 300,000 or more alongside styrene-based thermoplastic elastomer (1b) with styrene content of no greater than 20% by mass
3Object-affected harmful factors
If volatile components are reduced to improve volatility resistance, then fogging resistance is improved, but workability deteriorates
Solution Approach 1:
The patent selects paraffin oils with specific molecular weight ranges (high molecular weight paraffin oil (3a) with weight average molecular weight of 1,000 or more, and low molecular weight paraffin oil (3b) with weight average molecular weight of less than 1,000) and optimizes their content to reduce volatility and fogging while maintaining appropriate viscosity for workability
Data Source
AI summary
An object of the present invention is to provide a hot-melt composition which has excellent workability, hot flow resistance, balance between adhesion and detachability, volatility resistance, and hot creep resistance. The present invention is a hot-melt composition comprising: as thermoplastic elastomers (1), a styrene-based thermoplastic elastomer (1a) having a weight average molecular weight of 300,000 or more, a styrene-based thermoplastic elastomer (1b) having a styrene content of no greater than 20% by mass, and an olefin-based thermoplastic elastomer (1c) including an ethylene propylene rubber and/or butyl rubber; as tackifiers (2), an aromatic petroleum resin (2a), a terpene phenol resin (2b), and an amorphous polyalphaolefin (2c); a high molecular weight paraffin oil (3a) having a weight average molecular weight of 1,000 or more; and a low molecular weight paraffin oil (3b) having a weight average molecular weight of less than 1,000.