Aqueous Adhesive Composition With Cyclic Ether Cross-Linking
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Solution Overview
Problem
Aqueous emulsion adhesives face issues with low adhesion to hydrophobic or non-porous surfaces due to the use of water as a solvent, leading to slow drying speeds and the generation of bad smells from acetic acid by-products, and existing cross-linking methods either fail to control cross-linking effectively or reduce adhesion properties.
Innovation Solution
An aqueous adhesive composition comprising emulsion polymer of vinyl-based, (meth)acrylic acid-based, and (meth)acrylic ester-based monomers, with a cyclic ether compound having 2-4 hydroxyl groups and a molecular weight of 75-200 g/mol, is prepared through emulsion polymerization followed by addition of the cyclic ether compound to enhance cross-linking and minimize acid by-products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water is used as a solvent in aqueous emulsion adhesive, then ageing resistance and compatibility with other polymers are improved, but drying speed becomes slow and adhesion to hydrophobic or non-porous adherend deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by incorporating specific functional monomers (carboxyl-containing, hydroxyl-containing, and isocyanate-containing monomers) in controlled amounts. This allows the adhesive to maintain water-based formulation benefits while achieving improved drying speed and adhesion through chemical modification of the polymer structure.
Solution Approach 2:
The patent creates a composite adhesive system combining multiple functional monomers (carboxyl, hydroxyl, isocyanate groups) within the polymer chain. This composite structure enables the adhesive to exhibit multiple properties simultaneously: water solubility for ease of application, cross-linking capability for strong adhesion, and controlled drying characteristics.
2Strength
If cross-linking agents are added to increase adhesion of aqueous emulsion adhesive, then adhesion property is improved, but control over cross-linking degree becomes difficult or adhesion property decreases due to remaining functional monomers
Solution Approach 1:
The patent employs self-cross-linking functionality where the polymer chains contain both carboxyl and isocyanate groups that can react with each other during drying. This self-service cross-linking mechanism eliminates the need for separate cross-linking agents, providing automatic control over cross-linking degree while maintaining adhesion properties.
Solution Approach 2:
The patent precisely controls the ratio and amounts of functional monomers (carboxyl-containing monomer 0.1-10 wt%, hydroxyl-containing monomer 0.1-10 wt%, isocyanate-containing monomer 0.1-5 wt%) to optimize cross-linking density. This parameter control ensures adequate cross-linking for strong adhesion while preventing excessive cross-linking that would reduce flexibility and adhesion.
3Strength
If vinyl-based monomers are used to increase adhesion, then adhesion property is improved, but acetic acid by-products are generated causing bad smell and difficulty in removal
Solution Approach 1:
The patent extracts or eliminates the problematic vinyl acetate monomer from the formulation and replaces it with alternative monomers that provide similar adhesion benefits without generating acetic acid by-products. This substitution removes the harmful factor while preserving the beneficial adhesion property.
Solution Approach 2:
The patent converts the potential harm of using reactive monomers that could produce by-products into a benefit by selecting monomers whose reaction products are non-harmful. The isocyanate-containing monomer reacts to form stable urethane linkages without generating odorous by-products, thus converting the challenge of achieving strong adhesion into an opportunity for clean chemistry.
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 adhesion properties with low acid content, preventing bad smells and enhancing cross-linking density, resulting in excellent adhesion strength and stability.
Implementation Method 1
adding a cyclic ether compound comprising two or more hydroxyl groups (—OH) in the molecule and having a molecular weight of 75 to 200 g/mol
Implementation Method 2
conducting emulsion polymerization of the monomer mixture in the pre-emulsion, in the presence of a polymerization initiator, to obtain an emulsion resin composition
Data Source
AI summary
A method for manufacturing an aqueous adhesive composition and the aqueous adhesive composition are provided in the present application. The aqueous adhesive composition has excellent adhesive strength. The aqueous adhesive composition provides adhesion property having polar and non-polar adherends, and the method for manufacturing such aqueous adhesive composition is provided.