UV Curable Primer Composition for Olefin Foam Adhesion
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Solution Overview
Problem
The low surface energy of olefin-based polymers, such as olefin multi-block copolymers, poses challenges for bonding, painting, and printing, leading to adhesion issues, particularly in footwear assembly where high green peel strength is required to prevent delamination during compression and transportation.
Innovation Solution
A composition comprising modifiers with reactive hydrogen groups, acrylate-containing oligomers, random terpolymers, chlorinated olefin-based polymers, and styrene-based block interpolymers, which enhance the interaction between the UV curable primer and PU adhesive layer, improving green peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher olefin-based polymer content is used in midsole formulation, then productivity and material flexibility are improved, but adhesion performance deteriorates due to low surface energy
Solution Approach 1:
A UV curable primer composition is introduced as an intermediary layer between the olefin-based midsole and the bonding substrate. The primer contains modifiers with reactive hydrogen groups that form strong chemical bonds with both the olefin surface and the bonding adhesive, solving the adhesion problem while allowing high olefin content in the midsole formulation
Solution Approach 2:
The surface energy parameter of the olefin-based polymer is modified by applying the UV primer composition. The primer changes the surface properties from low surface energy (non-polar) to high surface energy (polar), enabling strong adhesion while maintaining the bulk properties and productivity benefits of high olefin content
2Strength
If UV primer composition is applied to enhance adhesion, then bonding strength is improved, but green peel strength may be insufficient during compression and transportation
Solution Approach 1:
The UV primer composition is applied and cured before the bonding process, creating a pre-treated surface that is optimized for adhesion. The primer forms strong chemical bonds with the olefin surface in advance, ensuring that when compression and transportation occur, the bond strength is already established and sufficient to prevent delamination
Solution Approach 2:
The UV primer composition is formulated as a composite material containing modifiers with reactive hydrogen groups, acrylate-containing oligomers, random terpolymers, and styrene-based block interpolymers. This composite structure provides both strong bonding capability and high green peel strength, meeting both requirements simultaneously
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 significantly increases green peel strength, ensuring the bonded shoe products do not delaminate during post-treatment processes, thereby enhancing production quality and allowing for higher olefin-based polymer content in midsole formulations.
Implementation Method 1
a) at least one photopolymerizable composition, most or all curable by UV, and wherein the composition comprises from 0.1 to 10 wt% combined amount of components A), B), C) and D) and from 99.9 to 90 wt% of the one or more non-aromatic and nonchlorinated organic solvents
Data Source
Figure 1~2
AI summary
Polymer compositions for UV curable primer formulations, as described herein. The primer formulations contain a modifier selected from the following: at least one modifier selected from a) through d) below: a) R1R2C ＝ CR3- (CO) -Z (Formula A), as described herein, b) an acrylate-containing oligomer that has a Mn ≤ 1500 g/mol, and an acid value from 50 to 500 mg KOH/g; c) a random terpolymer comprising, in polymerized form, vinyl chloride, vinyl acetate, and at least one of the following: a hydroxyl-containing alkyl acrylate, a hydroxyl-containing alkyl meth-acrylate, or a combination thereof or d) any combination of a) through c). Such primer formulations are useful for the binding of olefin-based polymer foams.