Hydrogel Adhesive Composition Using Thermal Crosslinking
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Solution Overview
Problem
Current hydrogel adhesives face issues with residual monomer levels, toxic by-products, high water content leading to adhesion property changes, and costly production processes, particularly during UV polymerization, which complicates large-scale coating and drying.
Innovation Solution
A hydrogel adhesive composition comprising a binder polymer and a water-soluble plasticizer, with controlled monomer levels and minimal water content, using a template polymerization process that reduces toxic by-products and capital requirements, and allows for crosslinking in the presence of plasticizers to form a 3-dimensional matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photopolymerization is used to crosslink the adhesive, then adhesion properties are improved, but toxic by-products such as acrolein are produced and residual monomer levels become unknown
Solution Approach 1:
The patent changes the crosslinking mechanism from photopolymerization to thermal crosslinking by incorporating crosslinkable functional groups (epoxide, carboxyl, hydroxyl, amine) into the polymer backbone. This allows the adhesive to achieve crosslinked structure through heat treatment instead of UV light, eliminating toxic by-products while maintaining adhesion properties
Solution Approach 2:
The patent uses readily available monomers with crosslinkable functional groups that can be polymerized through simple thermal processes, replacing expensive photoinitiators and UV equipment. The crosslinking occurs through conventional heating, making the process more accessible and eliminating the need for specialized photopolymerization equipment
2Reliability
If high water content is maintained in the hydrogel adhesive, then adhesion properties are improved, but water evaporation during storage causes stiffening and poor tack
Solution Approach 1:
The patent creates a composite hydrogel system combining water-soluble polymer chains with crosslinkable functional groups and plasticizers. The crosslinked network structure provides stability to the hydrogel matrix, preventing excessive water loss and maintaining adhesion properties during storage while still allowing controlled water content for initial tack
Solution Approach 2:
The patent incorporates crosslinkable functional groups and plasticizers into the adhesive formulation before application. The crosslinking process creates a stable network structure that cushions against water evaporation effects during storage, preventing the adhesive from becoming too stiff while maintaining adequate tack
3Ease of manufacture
If UV polymerization is used for production, then adhesive formation is achieved, but capital requirements and process complexity increase
Solution Approach 1:
The patent replaces the UV photopolymerization system (optical/chemical) with a thermal polymerization system. By incorporating crosslinkable functional groups into the polymer backbone, the adhesive can be formed through conventional heat treatment, eliminating the need for UV lamps, photoinitiators, and nitrogen purging equipment
Solution Approach 2:
The patent extracts and removes the complex UV polymerization components (photoinitiators, UV lighting system, nitrogen atmosphere requirements) from the manufacturing process. The crosslinking functionality is built into the polymer structure itself, allowing simple thermal processing without specialized equipment
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 consistent adhesion properties with minimal residue, reduced water-induced changes, and lower production costs, enabling efficient large-scale production and application with improved adhesion and peel characteristics.
Implementation Method 1
Crosslinking of the constituents suitably takes place in the presence of the plasticizer, which creates a three dimensional matrix
Implementation Method 2
The invention is directed to an adhesive composition which comprises at least a binder polymer and a water-soluble plasticizer
Data Source
AI summary
An adhesive composition comprises at least a binder polymer and a water-soluble plasticizer. The binder polymer may be present in a range of about 10% to about 60% by weight of the adhesive composition, and the plasticizer may be present in the range of about 5% to about 85% by weight of the adhesive composition, such as in the range of about 40% to about 80% by weight. In some aspects, the adhesive also comprises less than 10% by weight highly-volatile component, such as about 0% to about 5% by weight. The adhesive composition can be utilized in a variety of articles, including personal care articles, health/medical articles, and household/industrial articles.