Solventless Adhesive Hydrogen-Bonding Polyol Initial Bond Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Two-component solventless polyurethane-based laminating adhesive compositions exhibit weak initial bonds, slow bond development, poor chemical resistance, especially in acidic conditions, and inadequate heat seal strength, with silane adhesion promoters being sensitive to heat and moisture, limiting their effectiveness.
Innovation Solution
A two-component solventless adhesive composition comprising an isocyanate component derived from a reaction of polyisocyanate, polyester or polyether polyol, and a polyol with two or more hydroxyl groups and a hydrogen-bridging group, combined with a polyol component, enhancing bond strength and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If silane adhesion promoter is incorporated to improve initial bond strength, then bond strength is improved, but the adhesive composition becomes sensitive to moisture and heat, reducing reliability
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating polyols with specific hydrogen-bridging groups (carboxyl, carbonyl, or hydroxyl groups) in controlled amounts (0.01 to 25% by weight). This parameter change allows the adhesive to achieve good initial bond strength without the moisture sensitivity problems associated with silane adhesion promoters, as these polyols provide alternative hydrogen bonding mechanisms that are stable under heat and moisture conditions.
2Reliability
If two-component solventless polyurethane adhesive is used, then chemical resistance is improved, but bond development is slow and initial bond strength is weak
Solution Approach 1:
The patent creates a composite adhesive system by combining isocyanate component with polyol component containing specific hydrogen-bridging groups. This composite approach integrates the chemical resistance of polyurethane with the rapid bonding capability of hydrogen-bonding polyols, achieving both durability and initial strength without compromising either property.
Solution Approach 2:
The polyols with hydrogen-bridging groups act as intermediary substances that facilitate rapid initial bonding through hydrogen bonding, while the polyurethane matrix provides long-term chemical resistance. These intermediary polyols bridge the gap between the isocyanate and polyol components, enabling fast initial adhesion that later develops into durable chemical-resistant bonding.
3Productivity
If solventless adhesive is used, then drying time is reduced and productivity is improved, but bond strength and chemical resistance are insufficient
Solution Approach 1:
The patent modifies the adhesive composition by incorporating polyols with specific hydrogen-bridging groups (carboxyl, carbonyl, or hydroxyl groups) at controlled concentrations (0.01 to 25% by weight). This parameter change enables the solventless adhesive to achieve rapid initial bonding through hydrogen bonding while maintaining the chemical resistance and durability required for industrial applications.
Solution Approach 2:
The invention creates a composite adhesive system combining isocyanate prepolymer with polyol component containing hydrogen-bridging groups. This composite structure provides both the rapid bonding characteristics needed for high productivity and the chemical resistance required for durable applications, eliminating the trade-off between speed and performance.
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 composition achieves improved bond strength, chemical resistance, and heat seal strength, maintaining performance even after exposure to heat and acidic conditions, with the inclusion of a polyol having hydrogen-bridging groups in the isocyanate prepolymer reactants.
Implementation Method 1
a polyol having two or more hydroxyl groups and a hydrogen-bridging group selected from O=C-O
Implementation Method 2
an isocyanate component comprising an isocyanate prepolymer that is the reaction product of reactants comprising at least one polyisocyanate, at least one polyol selected from the group consisting of a polyester polyol, a polyether polyol
Data Source
AI summary
A two-component solventless adhesive composition is disclosed, the composition comprising an isocyanate component comprising an isocyanate prepolymer that is the reaction product of reactants comprising at least one polyisocyanate, at least one polyester polyol, at least one polyether polyol, and at least one polyol comprising a hydroxyl and COOH acid functionality. The adhesive composition further comprises a polyol component comprising at least one polyester polyol, at least one polyether polyol, or a combination thereof. A method for forming a laminate using the adhesive composition and a laminate itself are also disclosed. The method comprises forming a solventless adhesive composition, applying a layer of the adhesive composition to a surface of a film, bringing the layer into contact with a surface of another film to form a laminate, and curing the adhesive composition. A laminate made according to the method is further disclosed.