Emulsion Adhesive Composition for Low-Surface Energy Bonding
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Solution Overview
Problem
Existing emulsion-based pressure-sensitive adhesive compositions face challenges in achieving strong adhesion on low-surface energy materials, particularly in high humidity conditions, and require improved weight-added peel-off (WAPO) performance and static shear resistance.
Innovation Solution
An acrylic emulsion-based pressure-sensitive adhesive composition is developed by emulsion polymerization using a combination of non-ionic and ionic reactive surfactants, with specific amounts of a tackifier having a high softening point, enhancing both WAPO performance and static shear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If emulsion-based pressure-sensitive adhesive compositions are used to achieve environmentally friendly production, then production safety and environmental sustainability are improved, but adhesion performance on low-surface energy materials deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive by incorporating specific functional monomers (carboxyl-containing and hydroxyl-containing monomers) in controlled amounts (0.1-10 wt% and 0.1-5 wt% respectively). This parameter adjustment enables the adhesive to achieve strong bonding on low-surface energy materials while maintaining environmental sustainability through water-based emulsion formulation.
Solution Approach 2:
The invention creates a composite adhesive system by combining multiple components: acrylic polymer base, carboxyl-containing monomers, hydroxyl-containing monomers, and optional silane crosslinking agents. This composite formulation synergistically improves adhesion to low-surface energy materials like polypropylene and polyethylene while maintaining the environmentally friendly emulsion-based production approach.
2Ease of manufacture
If conventional adhesive formulations are used to achieve ease of manufacture, then production complexity is reduced, but WAPO performance and static shear resistance deteriorate
Solution Approach 1:
The invention optimizes the molecular weight and composition parameters of the acrylic polymer (weight-average molecular weight 100,000-1,000,000) and controls the ratios of functional monomers to achieve enhanced WAPO performance (≥500 g) and static shear resistance (≥24 hours at 500 g) while maintaining a relatively simple emulsion polymerization manufacturing process.
Solution Approach 2:
The carboxyl-containing and hydroxyl-containing monomers act as intermediary functional groups that enhance the interaction between the adhesive and low-surface energy substrates. These functional groups serve as chemical mediators that improve adhesion without requiring complex manufacturing processes, achieving high WAPO performance through controlled chemical composition rather than process complexity.
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 exhibits improved adhesion retention under high moisture, enhanced WAPO properties, and superior static shear resistance, effectively bonding to low-surface energy surfaces while maintaining mechanical stability.
Implementation Method 1
the acrylic polymer has been prepared by emulsion polymerization in the presence of a non-ionic reactive surfactant and an ionic reactive surfactant
Implementation Method 2
emulsion polymerization of monomers constituting an acrylic base polymer in the presence of a combination of non-ionic and ionic reactive surfactants
Implementation Method 3
admixing specific amounts of a tackifier with a high softening point to the thus obtained acrylic polymer substantially improves the WAPO performance of the resulting pressure-sensitive adhesive composition while further exhibiting an improved static shear resistance
Data Source
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AI summary
A pressure-sensitive adhesive composition which simultaneously enables improved weight-added-peel-off (WAPO) performance and static shear resistance is described, the pressure-sensitive adhesive composition comprising: an acrylic polymer, and an emulsified tackifier; wherein the emulsified tackifier has a softening point measured according to JIS K5902 and JIS K2207 of 120 °C or higher, and a content of the emulsified tackifier is higher than 10 parts by weight and 40 parts by weight or less relative to 100 parts by weight of the solid matter of the acrylic polymer; and wherein the acrylic polymer has been prepared by emulsion polymerization in the presence of a non-ionic reactive surfactant and an ionic reactive surfactant is described. In further aspects, a pressure-sensitive adhesive sheet or tape comprising a pressure-sensitive adhesive layer formed from the aforementioned pressure-sensitive adhesive composition.