Acrylic Pressure-Sensitive Adhesive for Polyolefin Substrates
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Solution Overview
Problem
Acrylic pressure-sensitive adhesive tapes or sheets face challenges in achieving satisfactory adhesive performance on nonpolar substrates like polyolefins and poorly adherent coated plates, with existing solutions either compromising low-temperature adhesiveness or leading to deterioration over time.
Innovation Solution
An acrylic pressure-sensitive adhesive comprising an acrylic polymer and a tackifier resin, where the polymer and/or tackifier resin contain two kinds of monomer units with a solubility parameter difference of 0.2 (MPa)1/2 or more, each in amounts of 15% by weight or more, enhancing compatibility and maintaining adhesive performance over storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monomer having a Tg of 15°C or more is copolymerized to improve adhesive performance to nonpolar adherends, then adhesive performance to polyolefins is improved, but low-temperature adhesiveness deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) of the copolymer to be within 15-30°C and the copolymerization amount to be 5-50 parts by weight per 100 parts of acrylic polymer. This optimized parameter range allows the adhesive to maintain both improved performance on nonpolar adherends and acceptable low-temperature adhesiveness, resolving the contradiction between these two performance requirements.
2Reliability
If a specific tackifier resin is added to improve adhesive performance to nonpolar adherends, then adhesive performance is improved, but compatibility with acrylic polymer deteriorates
Solution Approach 1:
The patent resolves the compatibility issue by changing the parameters of the tackifier resin, specifically selecting resins with glass transition temperatures between -50°C and 0°C and controlling the addition amount to 1-50 parts by weight per 100 parts of acrylic polymer. This parameter optimization ensures both improved adhesive performance and maintained compatibility.
Solution Approach 2:
The patent creates a composite material system combining acrylic polymer with specifically selected tackifier resins (rosin, hydrogenated petroleum-based resin, or acrylic oligomer) in optimized proportions. This composite approach achieves synergistic effects where the tackifier resin enhances adhesion to nonpolar adherends while the controlled composition maintains compatibility and prevents phase separation.
3Reliability
If acrylic oligomer with weight-average molecular weight of 20,000 or less is added to improve adhesive performance to polyolefins, then adhesive performance is improved, but compatibility with acrylic polymer deteriorates
Solution Approach 1:
The patent resolves the compatibility problem by changing the molecular weight parameter of the acrylic oligomer to have a weight-average molecular weight between 2,000 and 20,000, and controlling the addition amount to 1-50 parts by weight per 100 parts of acrylic polymer. This parameter optimization allows the oligomer to improve adhesion to polyolefins while maintaining compatibility and preventing deterioration during storage.
4Reliability
If polar monomer is added at high parts to improve adhesive performance to poorly adherent coated plates, then adhesive performance is improved, but water resistance deteriorates
Solution Approach 1:
The patent resolves the water resistance issue by changing the parameter of polar monomer addition to a controlled range of 1-30 parts by weight per 100 parts of acrylic polymer, rather than high parts. This optimized parameter range provides sufficient adhesive performance to poorly adherent coated plates while maintaining adequate water resistance.
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 solution provides excellent adhesive performance to polyolefin adherends and poorly adherent coated plates with minimal changes in adhesive strength after storage, ensuring durability and reliability of the acrylic pressure-sensitive adhesive layer and tape or sheet.
Implementation Method 1
acrylic pressure-sensitive adhesive excellent in adhesive performance to polyolefin adherends or poorly adherent coated plates
Implementation Method 2
excellent in pressure-sensitive adhesiveness such as pressure-sensitive adhesive force and cohesive force
Implementation Method 3
the acrylic polymer and/or the tackifier resin contain two kinds of monomer units having a difference in solubility parameter (SP value) of 0.2 (MPa)1/2 or more, each in an amount of 15% by weight or more
Data Source
AI summary
The present invention relates to an acrylic pressure-sensitive adhesive including: a) an acrylic polymer containing, as a monomer unit, an alkyl (meth)acrylate including an alkyl group having 1 to 20 carbon atoms in an amount of 50% by weight or more; and b) a tackifier resin, in which the acrylic polymer a) contains two kinds of monomer units having a difference in solubility parameter (SP value) of 0.2 (MPa)1/2 or more, each in an amount of 15% by weight or more.