Crystalline Polyester Resin for Adhesion and Blocking Resistance
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Solution Overview
Problem
Existing polyester resins face issues with inadequate blocking resistance, heat-sealability, and water resistance, particularly when used in amorphous forms or those containing sulfonic acid metal salts, which affect their suitability for food packaging applications.
Innovation Solution
A crystalline polyester resin composition is developed, comprising specific ratios of terephthalic acid, 1,4-cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids, with controlled glass transition temperature, melting point, and molecular weight, and free from sulfonic acid metal salts, formulated into an aqueous dispersion with optional inorganic particles and surfactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aromatic dicarboxylic acid having sulfonic acid metal salt is contained in polyester resin to improve adhesiveness, then adhesiveness is enhanced, but hygiene and water resistance deteriorate
Solution Approach 1:
The patent removes sulfonic acid metal salt components from the polyester resin composition. By extracting the harmful sulfonic acid metal salt additive that previously provided adhesiveness, the invention eliminates hygiene and water resistance problems while maintaining adhesion through alternative means (the specific copolymer structure with terephthalic acid, 1,4-cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acid in controlled ratios).
Solution Approach 2:
The patent changes the chemical composition parameters of the polyester resin by precisely controlling the molar ratios of copolymerization components (terephthalic acid: 30-70 mol%, 1,4-cyclohexanedicarboxylic acid: 10-60 mol%, aliphatic dicarboxylic acid: 5-30 mol%) and restricting aromatic dicarboxylic acid with sulfonate groups to less than 3 mol%. This parameter optimization achieves adhesiveness without relying on sulfonic acid metal salts, thereby improving hygiene and water resistance.
2Strength
If polyester resin is formulated for high adhesiveness using conventional additives, then adhesiveness improves, but storage stability and water resistance worsen
Solution Approach 1:
The patent creates a composite polyester resin system by copolymerizing multiple components (terephthalic acid, 1,4-cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acid with 10 or fewer carbon atoms) in specific ratios. This composite structure inherently provides adhesiveness, storage stability, and water resistance without requiring harmful additives, as the synergistic combination of copolymer components delivers multiple performance benefits simultaneously.
Data Source
AI summary
An object of the present invention is to provide an adhesive composition and a coating composition that have storage stability, high adhesiveness, and excellent blocking resistance and water resistance. The present invention provides a crystalline polyester resin comprising: a polyvalent carboxylic acid component and polyhydric alcohol component as a copolymerization components, wherein, 30 to 70 mol % of terephthalic acid, 10 to 60 mol % of 1,4-cyclohexanedicarboxylic acid, 5 to 30 mol % of aliphatic dicarboxylic acid having 10 or smaller of carbon atoms, and less than 3 mol % of an aromatic dicarboxylic acid component having a sulfonate group are contained as the polyvalent carboxylic acid component; and 50 to 100 mol % of 1,4-butanediol is contained as the polyhydric alcohol; wherein, an acid value of the crystalline polyester resin is 100 to 600 eq/t; a glass transition temperature of the crystalline polyester resin is −30 to 30° C.; a melting point of the crystalline polyester resin is 70 to 160° C.; and a number-average molecular weight of the crystalline polyester resin is 5000 to 40000.