Pressure-Sensitive Adhesive Composition for Low Surface Energy Substrates
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Solution Overview
Problem
Conventional pressure-sensitive adhesives do not effectively adhere to low surface energy substrates, particularly at elevated temperatures, due to their limited compatibility and stability issues when exposed to higher temperatures.
Innovation Solution
A pressure-sensitive adhesive composition comprising a low Tg (meth)acrylate copolymer and a high Tg (meth)acrylate copolymer, combined with a hydrogenated hydrocarbon tackifier, which provides improved adhesion and cohesion, especially at elevated temperatures, by incorporating high Tg monomers into the low Tg copolymer to stabilize microphase morphology and enhance compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure-sensitive adhesives are used, then they provide basic adhesive properties at room temperature, but they fail to maintain adhesion at elevated temperatures and on low surface energy substrates
Solution Approach 1:
The patent combines a low Tg (meth)acrylate copolymer component with a high Tg (meth)acrylate copolymer component in a composite adhesive system. The low Tg component provides tack and initial adhesion, while the high Tg component maintains cohesive strength and adhesion at elevated temperatures. This composite approach resolves the contradiction by integrating materials with complementary temperature-dependent properties, enabling reliable adhesion across a wide temperature range and on low surface energy substrates.
2Stability of the object's composition
If high Tg monomers are incorporated into the low Tg copolymer, then microphase morphology is stabilized and compatibility is enhanced, but the formulation complexity increases
Solution Approach 1:
The patent incorporates high Tg monomers locally within the low Tg copolymer component at controlled levels (1-20 wt%). This local incorporation stabilizes the microphase morphology and enhances compatibility without requiring a complete reformulation of the entire adhesive system. The high Tg monomers are strategically placed within the polymer structure to provide thermal stability while maintaining the overall low Tg character needed for PSA performance.
Solution Approach 2:
The patent modifies the compositional parameters of the low Tg copolymer by incorporating specific amounts of high Tg monomers (1-20 wt%). This parameter change stabilizes the microphase morphology and improves compatibility with the high Tg copolymer component. By carefully controlling the concentration of high Tg monomers, the formulation achieves morphological stability without excessive 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 adhesive composition exhibits exceptional adhesion and shear holding power on low surface energy substrates, maintaining performance even at elevated temperatures, with improved peel values and cohesive strength due to microphase separation and the use of hydrogenated hydrocarbon tackifiers.
Implementation Method 1
incorporating high Tg monomers into the low Tg copolymer to stabilize microphase morphology and enhance compatibility
Implementation Method 2
exceptional adhesion to low surface energy substrates
Implementation Method 3
Materials that have been found to function well as PSAs include polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power
Data Source
AI summary
Disclosed is an adhesive composition comprising a low Tg(meth)acrylate copolymer component, a high Tg (meth)acrylate copolymer component, and a hydrogenated hydrocarbon tackifier. This disclosure provides a pressure-sensitive adhesive and pressure-sensitive adhesive articles that are particularly useful in the bonding of low surface energy (LSE) substrates.