Post-Polymerization Functionalization of Acrylic Block Copolymers
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Solution Overview
Problem
There is a need for adhesive compositions that utilize controlled architecture polymers to exhibit specific properties and characteristics upon activation, such as exposure to UV radiation, which existing adhesives fail to achieve effectively.
Innovation Solution
A composition comprising an acrylic block copolymer with reactive segments that undergo a post-polymerization functionalization reaction to become crosslinkable upon actinic radiation exposure, forming a pre-adhesive that can be cured into a pressure-sensitive adhesive, utilizing a reacting agent with a double bond and functional group capable of reacting with the copolymer's functional groups to introduce ethylenically unsaturated bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymers with functional groups are used, then adhesive compositions can be formed, but the adhesive properties and performance characteristics are insufficient compared to controlled architecture polymers
Solution Approach 1:
The polymer is divided into controlled architecture segments (backbone and pendant groups) with specific functional groups positioned at predetermined locations. This segmentation allows different regions of the polymer to contribute differently to adhesive performance, resolving the contradiction by providing both reliable adhesive properties through functional group placement and architectural control through segmented structure design
Solution Approach 2:
Functional groups are placed at specific local positions along the polymer backbone rather than uniformly distributed. This local quality approach ensures that reactive sites are positioned optimally for adhesive bonding while maintaining overall polymer stability, thereby achieving both high adhesive reliability and architectural precision
2Adaptability or versatility
If post-polymerization functionalization is performed to introduce UV-activatable groups, then crosslinkable adhesive properties are achieved, but the polymerization process complexity increases
Solution Approach 1:
The polymer backbone and pendant functional groups are pre-formed through controlled polymerization, and the UV-activatable crosslinking capability is introduced in a subsequent post-polymerization step. This preliminary action separates the polymerization process from the crosslinking activation, reducing overall process complexity while maintaining versatile adhesive functionality
Solution Approach 2:
A reacting agent serves as an intermediary between the pendant functional groups and the UV activation step. The reacting agent introduces ethylenically unsaturated bonds that enable crosslinking upon UV exposure, acting as a mediator that connects the polymer structure to the crosslinking mechanism without requiring direct integration of all functions in one step
3Ease of manufacture
If ethylenically unsaturated bonds are introduced through post-polymerization functionalization, then the polymer becomes crosslinkable upon UV exposure, but the initial polymer structure must be carefully controlled
Solution Approach 1:
The polymer backbone and pendant functional groups are precisely controlled during the initial polymerization step, creating a well-defined structure that facilitates subsequent crosslinking. This preliminary structural control makes the later crosslinking activation easier and more predictable, resolving the contradiction between manufacturing ease and precision requirements
Solution Approach 2:
The polymer structure parameters (molecular weight, functional group density, pendant group composition) are precisely controlled during synthesis to optimize both the ease of subsequent crosslinking and the final adhesive performance. By adjusting these parameters systematically, the invention achieves both manufacturing simplicity and structural precision
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 enables the formation of adhesives with enhanced adhesive properties like high peel strength and shear strength, achieving lower adhesive coat weights and viscosities, and improved performance compared to conventional randomly crosslinked networks.
Implementation Method 1
At least one of the functional groups of the at least one acrylic block copolymer can undergo a post-polymerization functionalization reaction with the reacting agent to make the at least one acrylic block copolymer crosslinkable upon exposure to an actinic radiation
Implementation Method 2
The precursor forms a pre-adhesive composition after the post-polymerization functionalization reaction and the pre-adhesive is at least partially crosslinkable upon exposure to the actinic radiation to form an adhesive
Data Source
AI summary
Modification of functional groups along a polymer backbone to render the groups activatable upon exposure to actinic radiation is described. The polymers are typically controlled architecture polymers. Also described are adhesives containing the modified architectured polymers and related methods of use.