Crystalline Polyester Resin Sealing Composition for Electronics
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Solution Overview
Problem
Existing thermoplastic hotmelt materials face issues with high melting point and fluidity, leading to concerns such as bleeding during long-term storage, decreased heat resistance, and poor adhesive properties under moist heat environments, particularly in sealing electric/electronic parts with complex shapes.
Innovation Solution
A crystalline polyester resin with a specific copolymerization ratio of 2,6-naphthalenedicarboxylic acid and 1,4-butanediol, combined with a flame retardant agent, optimized for a melting point between 100°C to 180°C and low melt viscosity, ensuring high fluidity and flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermoplastic hotmelt material with high melting point is used to ensure heat resistance, then the heat resistance is improved, but the fluidity deteriorates
Solution Approach 1:
The invention uses a composite material system consisting of crystalline polyester resin as the base polymer, combined with specific additives including polyethylene wax and polypropylene. This composite structure allows the material to maintain high melting point (100-180°C) for heat resistance while the wax components provide lubrication that improves fluidity during the sealing process.
Solution Approach 2:
The invention optimizes the molecular weight parameters of the crystalline polyester resin and controls the melting point within a specific range (100-180°C). By adjusting these parameters and controlling the copolymerization ratio, the material achieves both high heat resistance and adequate fluidity for complex shape sealing applications.
2Object-generated harmful factors
If wax is added to improve viscosity characteristic at low temperatures, then the fluidity is improved, but bleeding-out occurs during long-term storage
Solution Approach 1:
The invention carefully controls the melting point of the crystalline polyester resin to be within 100-180°C, which is high enough to prevent wax bleeding during storage but low enough to provide good fluidity during sealing. This parameter optimization resolves the contradiction between preventing bleeding and maintaining fluidity.
Solution Approach 2:
The invention uses a specific composite formulation combining crystalline polyester resin with controlled amounts of polyethylene wax and polypropylene. This composite structure provides adequate fluidity for sealing while the controlled melting point prevents excessive wax migration during storage.
3Temperature
If the melting point is increased to ensure heat resistance, then the heat resistance is improved, but the adhesive property lowers under moist heat environment
Solution Approach 1:
The invention optimizes the melting point to be within 100-180°C and controls the number-average molecular weight of the crystalline polyester resin. These parameter optimizations ensure that the material maintains adequate adhesive properties under moist heat conditions while providing sufficient heat resistance for electronic component sealing applications.
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 solution provides a thermoplastic hotmelt material with improved heat resistance, fluidity, and flame retardancy, suitable for sealing electric/electronic parts while maintaining low melt viscosity and excellent adhesive properties.
Implementation Method 1
A thermoplastic hotmelt material lowers its viscosity by being heated and melted up to a melting point or higher
Implementation Method 2
The thermoplastic hotmelt material having good fluidity has been preferred in view of a sure following to the shapes of the electric/electronic parts
Data Source
Figure 1
AI summary
The present invention aims to provide a crystalline polyester resin which satisfies both of a high melting point and a high fluidity, and a flame-retardant sealing resin composition using the same. A crystalline polyester resin (A) containing polycarboxylic acid components and polyhydric alcohol components as copolymerizing components, characterized in that a copolymerizing rate of a 2,6-naphthalenedicarboxylic acid component is from 40 to 100 molar % when a total of the polycarboxylic acid components in the crystalline polyester resin (A) is taken as 100 molar %, that a 1,4-butanediol component is copolymerized as a polyhydric alcohol component, and that a copolymerizing rate of the 1,4-butanediol component is 40 molar % or less when a total of the polyhydric alcohol components is taken as 100 molar %.