Aqueous Acrylic PSA Sheet Foam Repulsion Resistance
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Solution Overview
Problem
Existing aqueous acrylic pressure-sensitive adhesive (PSA) compositions face challenges in achieving high foam repulsion resistance while maintaining other essential properties like adhesiveness and cohesive strength, especially in high-temperature environments, when used to bond foam members to adherends.
Innovation Solution
A double-sided PSA sheet comprising an aqueous pressure-sensitive adhesive composition primarily made from an acrylic polymer, where the polymer is obtained by polymerizing a starting monomer material with an alkyl (meth)acrylate content of 80% or more, containing both acrylic acid and methacrylic acid, and including a silanol-forming monomer, which enhances foam repulsion resistance and maintains adhesiveness and cohesive strength in a balanced manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an aqueous acrylic PSA composition is used to bond foam members, then environmental friendliness and ease of manufacture are improved, but foam repulsion resistance is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the acrylic polymer by incorporating both acrylic acid and methacrylic acid in specific ratios, along with alkyl (meth)acrylate content of 80 mass% or more. This parameter optimization enables the aqueous PSA composition to achieve high foam repulsion resistance while maintaining environmental friendliness and ease of manufacture.
Solution Approach 2:
The patent creates a composite acrylic polymer system combining multiple monomer types (acrylic acid, methacrylic acid, and alkyl (meth)acrylate) to achieve synergistic effects. This composite material approach provides both the required foam repulsion resistance and the benefits of aqueous-based formulations.
2Reliability
If foam repulsion resistance is increased, then bonding performance on curved surfaces is improved, but adhesiveness and cohesive strength may be compromised
Solution Approach 1:
The patent optimizes the balance between foam repulsion resistance and cohesive strength by precisely controlling the monomer composition ratios. The specific formulation with alkyl (meth)acrylate at 80 mass% or more, combined with acrylic acid and methacrylic acid, creates a polymer structure that simultaneously provides high foam repulsion resistance and maintains cohesive strength even in high-temperature environments.
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 PSA sheet exhibits superior foam repulsion resistance, adhesiveness, and high-temperature cohesive strength, ensuring effective bonding of foam members to adherends while maintaining a good balance of properties.
Implementation Method 1
the acrylic polymer is obtained by polymerizing a starting monomer material containing an alkyl (meth)acrylate as a main monomer, the alkyl (meth)acrylate content of the starting monomer material being 80 mass% or more; and the starting monomer material contains acrylic acid and methacrylic acid
Implementation Method 2
An aqueous dispersion-type (aqueous) PSA composition in which an acrylic polymer is dispersed in water uses water as the dispersion medium
Implementation Method 3
the aqueous pressure-sensitive composition further comprises 5 to 40 parts by mass of a tackifier to 100 parts by mass of the acrylic polymers; and wherein the tackifier is selected from rosin-based resins, rosin derivative resins and terpene-based resins
Data Source
Figure 1~3
Figure 4~6
AI summary
Provided are a pressure-sensitive adhesive (PSA) sheet having excellent foam repulsion resistance and an aqueous PSA composition suitable for preparing this sheet. The composition primarily comprises an acrylic polymer obtained by polymerizing a starting monomer material containing an alkyl (meth)acrylate as a main monomer and both acrylic acid and methacrylic acid. The acrylic polymer preferably has a weight average molecular weight of 65 × 104 to 100 × 104. The starting monomer material is preferred to further contain a silanol-forming monomer and polymerized without the silanol-forming monomer to produce a polymer having a gel fraction of 7 to 17 mass%. The post-crosslink PSA preferably has a gel fraction of 20 to 55 mass%.