Solventless Laminate Adhesive Viscosity Control
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Solution Overview
Problem
Two-component curable solventless-type laminate adhesives face challenges with high viscosity immediately after mixing, leading to insufficient adhesive strength and delamination issues during continuous application and lamination processes.
Innovation Solution
A two-component curable solventless-type laminate adhesive is developed with a polyisocyanate component containing a derivative of pentamethylene diisocyanate, which includes an isocyanurate and allophanate group, and a polyol component with a specific mass ratio, resulting in low viscosity and extended pot life, enhancing adhesive strength and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a two-component curable solventless-type adhesive is used to eliminate organic solvent and improve environmental protection, then resource saving and working environment improvement are achieved, but the viscosity of the solid content must be suppressed relatively low for continuous application, which is difficult to achieve compared to solvent-type adhesives
Solution Approach 1:
The patent changes the chemical parameters of the adhesive components by specifying precise molecular weight ranges for polyols (300-2000) and specific ratios of isocyanate to hydroxyl groups (0.5-3.0), which controls the viscosity and reactivity of the solventless adhesive to enable continuous application
Solution Approach 2:
The patent creates a composite adhesive system combining polyisocyanate component with specific polyol components (polyester polyol or polyurethane polyol) in controlled ratios (40-300 parts by mass), forming a composite material with optimized flow properties and adhesive performance for continuous lamination
2Ease of operation
If the polyol component contains a macrodiol with higher molecular weight to reduce viscosity for better processability, then low viscosity and long pot life are achieved, but the adhesive strength may be reduced
Solution Approach 1:
The patent optimizes the molecular weight parameter of the polyol component within the range of 300-2000, balancing the viscosity reduction benefit with sufficient adhesive strength by preventing the molecular weight from being too high
Solution Approach 2:
The patent introduces functional differentiation by specifying that the polyol component should be either polyester polyol or polyurethane polyol with specific properties, creating local optimization in the adhesive system for both processability and strength
3Ease of operation
If the adhesive has low viscosity for easy application, then processability is improved, but the initial cohesive force is reduced causing delamination at the end portion of laminate product
Solution Approach 1:
The patent changes the equivalent ratio parameter of isocyanate group to hydroxyl group within 0.5-3.0, which controls the crosslinking density and initial cohesive force of the adhesive, preventing delamination while maintaining low viscosity
Solution Approach 2:
The patent creates a dynamic balance in the adhesive formulation where the polyol component with molecular weight 300-2000 provides initial low viscosity for easy application, while the controlled reaction stoichiometry ensures sufficient cohesive force develops during curing
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 adhesive exhibits improved viscosity control, prolonged pot life, and enhanced adhesive strength immediately after application, addressing delamination issues and ensuring continuous application and laminating properties.
Implementation Method 1
a two-component curable adhesive prepared from a polyisocyanate component and a polyol component
Data Source
AI summary
A two-component curable solventless-type laminate adhesive contains a polyisocyanate component and a polyol component. The polyisocyanate component contains a derivative of a pentamethylene diisocyanate, the derivative of the pentamethylene diisocyanate contains an isocyanurate group and an allophanate group, and the content ratio of the isocyanurate group with respect to 100 moles of the total amount of the isocyanurate group and the allophanate group is 60 moles or more and 99 moles or less.