Pressure-Sensitive Adhesive Composition for Chemical-Resistant Tack
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Solution Overview
Problem
Existing poly(meth)acrylate-based pressure-sensitive adhesives face a conflict between achieving high adhesive strength and maintaining chemical resistance, particularly against substances like ethanol/water mixtures and oleic acid, which is exacerbated by the use of conventional adhesive resins.
Innovation Solution
Incorporating specific (meth)acrylate-based adhesive resins produced from a monomer composition comprising aromatic (meth)acrylates and/or styrene into poly(meth)acrylate-based pressure-sensitive adhesives, with a balanced molecular weight distribution and crosslinking, to enhance both adhesive strength and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesive resins (terpene-phenol or rosin resins) are added to poly(meth)acrylate-based pressure-sensitive adhesives, then adhesive strength is improved, but chemical resistance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the adhesive resin by using specific (meth)acrylate-based resins with defined molecular weight ranges (5,000-50,000 g/mol) and specific functional group contents, rather than conventional terpene-phenol or rosin resins. This parameter change allows achieving high adhesive strength while preserving chemical resistance against substances like ethanol/water mixtures and oleic acid.
Solution Approach 2:
The invention creates a composite adhesive system by combining poly(meth)acrylate base polymers with specifically formulated (meth)acrylate-based adhesive resins. This composite approach leverages the chemical resistance of the poly(meth)acrylate base while the incorporated (meth)acrylate resins provide enhanced adhesive strength without compromising the overall chemical resistance of the system.
2Ease of operation
If adhesive resins are added to increase adhesive strength, then substrate wetting is improved, but the intrinsic chemical resistance of poly(meth)acrylate-based adhesives is reduced
Solution Approach 1:
The invention optimizes the molecular weight parameters of the adhesive resin within the range of 5,000-50,000 g/mol, which provides optimal balance between substrate wetting capability and chemical resistance. The specific parameter range ensures sufficient chain length for effective substrate interaction while maintaining resistance to chemical degradation.
Solution Approach 2:
The invention applies local quality by concentrating the adhesive functionality in the specifically formulated (meth)acrylate resin component, while the poly(meth)acrylate base polymer maintains its chemical resistance properties. This functional differentiation allows substrate wetting to be enhanced locally at the adhesive-resin level without compromising the overall chemical resistance of the adhesive system.
Data Source
AI summary
The invention relates to a pressure-sensitive adhesive comprising: a) one or more poly(meth)acrylates with a weight-average molecular weight Mw of 200,000 g/mol or more in a combined mass fraction of 50% or more, in relation to the mass of the pressure-sensitive adhesive, and b) one or more bonding resins with a weight-average molecular weight Mw of 20,000 g/mol or less in a combined mass fraction in the range of 1 to 25%, in relation to the mass of the pressure-sensitive adhesive, the one or more bonding resins being producible by polymerisation of a first monomer composition comprising, in relation to the mass of the first monomer composition: i) one or more first monomers, which are selected from the group consisting of aromatic (meth)acrylates and styrene, in a combined mass fraction in the range of 5 to 40%, ii) one or more second monomers, which are selected from the group consisting of methyl methacrylate and ethyl methacrylate, in a combined mass fraction in the range of 35 to 68%, and iii) one or more third monomers, which are selected from the group consisting of (meth)acrylates with a cycloaliphatic group, in a combined mass fraction in the range of 5 to 40%.