Aqueous Adhesive Composition Tack Shear Balance
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Solution Overview
Problem
Pressure-sensitive adhesives (PSAs) typically face a trade-off between high tack and desirable shear performance, with high tack often resulting in less than optimal shear performance.
Innovation Solution
An aqueous adhesive composition comprising 80% to 99% by weight of polymerized alkyl (meth)acrylate monomer units, 0.1% to 10% by weight of acrylic acid or methacrylic acid units, 0.1% to 15% by weight of dialkyl diester of itaconic acid units, and optionally up to 20% by weight of other monomer units, which maintains a balance between tack and shear performance for bonding substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a PSA has high tack, then adhesive strength is improved, but shear performance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer by incorporating dialkyl diester of itaconic acid units (0.1-15 wt%) alongside alkyl (meth)acrylate (80-99 wt%) and acrylic/methacrylic acid units (0.1-10 wt%). This compositional parameter change enables the adhesive to achieve both high tack (≥2.0 N/mm) and acceptable shear performance (≥24 hours), resolving the traditional trade-off between these two properties.
Solution Approach 2:
The patent creates a composite polymer system combining multiple monomer units with different functional properties. The dialkyl diester of itaconic acid units contribute to shear resistance while the alkyl (meth)acrylate units provide tack, forming a composite adhesive material that achieves balanced performance of both properties simultaneously.
2Strength
If a PSA has high tack, then initial bonding is improved, but long-term durability deteriorates
Solution Approach 1:
The patent modifies the polymer composition parameters to include specific amounts of dialkyl diester of itaconic acid (0.1-15 wt%) which provides long-term shear resistance while maintaining high tack (≥2.0 N/mm). This parameter optimization enables the adhesive to maintain both initial bonding strength and long-term durability (≥24 hours shear performance).
Solution Approach 2:
The patent develops a composite polymer structure where dialkyl diester of itaconic acid units provide structural stability for long-term durability while alkyl (meth)acrylate units provide adhesive strength for initial bonding. This composite approach achieves both high tack and extended service life simultaneously.
Data Source
AI summary
Provided is an aqueous adhesive composition comprising a polymer that comprises (a) polymerized units of one or more alkyl (meth)acrylate monomer, (b) polymerized units of acrylic acid or methacrylic acid or a mixture thereof, (c) polymerized units of one or more dialkyl diester of itaconic acid, and (d)polymerized units of one or more other monomer.