Polyester Hot Melt Adhesive Resin Composition
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Solution Overview
Problem
Conventional polyester-based hot melt adhesives with polybutylene terephthalate (PBT) suffer from volume shrinkage and detachment during cooling, requiring costly resin mixing steps to address these issues, while maintaining high crystallization rate, heat resistance, and adhesiveness.
Innovation Solution
A polyester resin composition comprising 50-85% aromatic dicarboxylic acid, 15-50% aliphatic acid, 90-98% aliphatic dihydric alcohol, and 2-10% polyether-based polyol, specifically including terephthalic acid, adipic acid, 1,4-butanediol, and polyethylene/polytetramethylene glycol, to enhance adhesiveness, flexibility, and processability without additional resin mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If PBT is used as the base resin, then heat resistance and initial adhesiveness are improved, but volume shrinkage occurs during cooling causing detachment
Solution Approach 1:
The patent creates a composite polyester resin system by copolymerizing PBT with specific amounts of polybutylene adipate (10-30 wt%) and polyethylene adipate (5-20 wt%). This composite approach combines the heat resistance of PBT with the flexibility and lower shrinkage characteristics of the adipate-based polyesters, resolving the contradiction between heat resistance and bonding reliability
Solution Approach 2:
The patent modifies the compositional parameters of the polyester resin by controlling the mole ratios of terephthalic acid (50-85 mol%) and adipic acid (15-50 mol%), and the molecular weights of the polyether-based polyols (1,000-5,000 g/mol). These parameter changes optimize the balance between crystallization rate, heat resistance, and volume shrinkage to prevent detachment
2Reliability
If polyolefin and polycarbonate resins are mixed to solve PBT disadvantages, then adhesiveness is improved, but production cost increases due to additional mixing step
Solution Approach 1:
The patent merges the modification steps into a single copolymerization process by incorporating polyether-based polyols directly into the polyester resin synthesis. This eliminates the need for separate mixing steps required by conventional approaches, thereby improving ease of manufacture while achieving the desired adhesive bonding reliability
Solution Approach 2:
The patent enables the polyester resin to self-adjust its properties during the copolymerization process. The controlled copolymerization of PBT with adipate-based components and polyether polyols occurs in one step, allowing the resin to self-optimize its adhesive and mechanical properties without requiring external mixing operations
3Ease of operation
If polyether-based polyol is added to improve flexibility and adhesiveness, then coating flexibility is improved, but crystallization rate may be reduced
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyether-based polyol (1,000-5,000 g/mol) and its content (2-10 mol%) to achieve the right balance. This controlled parameter change allows the polyether segments to provide flexibility and adhesiveness while the limited concentration and specific molecular weight range preserve sufficient crystallization rate
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 excellent adhesiveness, flexibility, and processability to various substrates, reducing volume shrinkage and production costs, while maintaining high crystallization and heat resistance, as demonstrated by improved physical properties and long-term adhesiveness in examples.
Implementation Method 1
a polyester resin for a hot melt adhesive that is excellent in adhesiveness to various substrates, has a high crystallization rate
Implementation Method 2
it has been evaluated as a polyester resin for a hot melt adhesive that is excellent in hydrolysis resistance
Data Source
AI summary
The present invention relates to a polyester resin composition for a hot melt adhesive and a polyester resin produced therefrom. The polyester resin is excellent in adhesiveness to plate substrates, flexibility, and processability.