Acidic Basic Copolymer Adhesive Composition Hot Melt Processing
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Solution Overview
Problem
Existing pressure sensitive adhesives (PSAs) require post-coating crosslinking processes, which are expensive and not suitable for hot melt or extrusion processes, limiting their cohesive strength and adhesion properties.
Innovation Solution
A non-aqueous composition of acidic and basic copolymers with amide functionality, blended in specific ratios, that can be processed through hot melt or extrusion without a secondary crosslinking step, providing adequate cohesive strength and adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If covalent crosslinking is used to improve cohesive strength, then adhesive strength is improved, but process complexity and equipment cost increase due to required post-coating radiation crosslinking
Solution Approach 1:
The invention changes the chemical nature of the adhesive composition by incorporating complementary acidic and basic polymers with specific functional groups. This chemical parameter change enables cohesive strength improvement through molecular interactions rather than requiring post-coating crosslinking processes, thus resolving the contradiction between strength enhancement and process complexity
Solution Approach 2:
The invention uses a composite system of acidic and basic polymers that work together to provide cohesive strength. The acidic polymer contains carboxylic acid or sulfonic acid groups while the basic polymer contains amine groups, creating a composite material system that achieves crosslinking-like effects through acid-base interactions without requiring external crosslinking equipment
2Strength
If thermally activated crosslinkers are used, then cohesive strength is improved, but adaptability decreases because they cannot be used with hot melt processable PSAs
Solution Approach 1:
The invention changes the activation mechanism from thermal to chemical (acid-base reaction). The acidic and basic polymers react upon contact to form strong bonds, enabling the adhesive to work with hot melt processable PSAs while maintaining cohesive strength improvement, thus resolving the contradiction between strength enhancement and process adaptability
3Strength
If adequate cohesive strength is achieved through crosslinking, then adhesion properties are improved, but manufacturing cost increases due to expensive post-coating crosslinking equipment
Solution Approach 1:
The acidic and basic polymers are self-reactive upon contact, forming strong bonds without requiring external crosslinking equipment or additional processing steps. This self-service mechanism eliminates the need for expensive post-coating facilities while maintaining adequate cohesive strength, resolving the contradiction between strength improvement and manufacturing cost
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 achieves sufficient cohesive strength and adhesion properties, allowing for the manufacture of adhesive articles with improved tack, peel strength, and resistance to cold flow, without the need for expensive post-coating crosslinking processes.
Implementation Method 1
The composition comprises a blend of an acidic copolymer derived from a first group of monomers comprising at least one acidic monomer and the acidic copolymer is substantially free of basic monomer, and a basic copolymer derived from a second group of monomers comprising at least one basic monomer. The composition comprises a minimum of 0.10 moles of acid/base pairs per kilogram of composition.
Data Source
AI summary
The present application is directed to a non-aqueous composition. The composition comprises a blend of an acidic copolymer derived from a first group of monomers comprising at least one acidic monomer, and a basic copolymer derived from a second group of monomers comprising at least one basic monomer. The basic copolymer may comprise an amide functionality. In some embodiments, the composition comprises an acidic (meth)acrylic copolymer having a Tg less than 0° C., which is derived from a first group of monomers comprising at least one acidic monomer, and a basic (meth)acrylic copolymer having a Tg less than 0° C., which is derived from a second group of monomers comprising at least one basic monomer. Additionally, the composition may comprise a minimum of 0.10 moles of acid/base pairs per kilogram of composition.