Acrylic Polymer Emulsion for Fast Moisture-Resistant Bonding
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Solution Overview
Problem
Water-based adhesives take a long time to develop PSA characteristics and are prone to moisture contamination, making them unsuitable for quick bonding under high temperature or humidity conditions, unlike solvent-based adhesives.
Innovation Solution
An emulsion comprising acrylic polymer particles with specific monomer units, including alkyl acrylate and methacrylate with at least 8 carbon atoms, acid-functional monomers, high Tg monomers, and chain terminal groups, which quickly develop adhesive properties upon application, enabling fast bonding and durability under adverse conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based adhesives are used instead of solvent-based adhesives, then volatile organic compounds are reduced and flammability is eliminated, but bonding speed and resistance to moisture contamination deteriorate
Solution Approach 1:
The patent modifies the chemical parameters of the acrylic polymer by incorporating specific monomer units (alkyl acrylate/methacrylate with 8+ carbon atoms, acid-functional monomers, high Tg monomers) and chain terminal groups with thioether linkages. These parameter changes enable the water-based emulsion to achieve rapid bonding (within one minute) while maintaining resistance to moisture contamination, thus resolving the contradiction between environmental safety and bonding performance.
2Object-affected harmful factors
If water-based adhesives are used instead of solvent-based adhesives, then volatile organic compounds are reduced and flammability is eliminated, but resistance to moisture contamination deteriorates
Solution Approach 1:
The patent creates a composite polymer structure within the acrylic polymer particles by combining multiple types of monomer units (alkyl acrylate/methacrylate, acid-functional monomers, high Tg monomers) and incorporating chain terminal groups with thioether linkages. This composite material approach provides both the environmental benefits of water-based adhesives and the moisture resistance typically associated with solvent-based systems.
Data Source
AI summary
An emulsion includes water, an emulsifier, and acrylic polymer particles dispersed in the water. The acrylic polymer particles include monomer units of an alkyl acrylate, alkyl methacrylate, or combination thereof, in which alkyl has at least eight carbon atoms; at least one percent by weight acid-functional monomer units, based on the total weight of the monomer units in the acrylic polymer particles; monomer units of a high Tg monomer comprising at least one of t-octyl acrylamide, t-butyl methacrylate, t-butyl acrylate, isobornyl acrylate, or isobornyl methacrylate; and a chain terminal group having at least four carbon atoms and a thioether group. In some embodiments, the emulsion provides an adhesive able to hold a pinch bond in a foam cube within one minute of spraying the emulsion. A process for making the composition and a process for making a bonded article using the composition are also described.