Adhesive Sheet for Vulcanized Rubber via Thiol-Ene Chemistry
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Solution Overview
Problem
Existing adhesive materials for vulcanized rubber lack sufficient adhesive power and require complex surface treatment processes, limiting their efficiency and effectiveness.
Innovation Solution
An adhesive sheet comprising a composition of a polythiol compound, a compound with multiple epoxy groups, a radical generator, and an amine-based catalyst, with a specific epoxy-to-thiol ratio, which promotes strong adhesion to rubber through thiol-ene reactions and chemical bonding, eliminating the need for surface roughening treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive materials are used for vulcanized rubber, then adhesion can be achieved, but adhesive power is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by specifying precise ratios of epoxy groups to thiol groups (0.05 < Ep/SH ≤ 0.5), and by controlling the molecular weight range of the polythiol compound (500-5000). These parameter optimizations enable the adhesive to achieve sufficient bonding strength to vulcanized rubber without requiring surface roughening treatments, thereby improving adhesive power while maintaining ease of manufacture
Solution Approach 2:
The patent creates a composite adhesive system combining polythiol compounds with multiple epoxy groups, radical generators, and amine-based catalysts. This composite formulation synergistically enhances adhesive power through multiple bonding mechanisms (thiol-ene click chemistry and epoxy-thiol reactions), achieving reliable adhesion to vulcanized rubber while eliminating complex surface treatment requirements
2Reliability
If surface treatment is applied to vulcanized rubber, then adhesion can be improved, but process complexity increases
Solution Approach 1:
The adhesive composition is designed to self-activate upon contact with vulcanized rubber, utilizing the rubber's inherent surface properties without requiring external surface treatment. The amine-based catalyst activates the epoxy and thiol groups to form chemical bonds directly with the rubber surface, making the adhesive system self-sufficient and eliminating complex surface treatment equipment and processes
Solution Approach 2:
The patent replaces mechanical surface treatment methods (such as roughening, etching, or abrasion) with a chemical bonding mechanism. The thiol-ene click chemistry and epoxy-thiol reactions provide direct chemical attachment to the rubber surface, substituting mechanical surface modification with a more efficient chemical interaction that requires no additional surface treatment equipment
3Strength
If high adhesive power is achieved through conventional methods, then bonding strength improves, but adhesion time and temperature requirements increase
Solution Approach 1:
The patent employs a two-stage curing mechanism where initial rapid bonding occurs through thiol-ene click chemistry, followed by secondary bonding through epoxy-thiol reactions. This periodic action pattern enables quick initial adhesion while continuing to strengthen the bond over time, reducing the overall adhesion time required to achieve sufficient bonding strength
Solution Approach 2:
The patent optimizes reaction parameters by controlling the Ep/SH ratio and using amine-based catalysts that accelerate the bonding reactions at lower temperatures. This enables high bonding strength to be achieved under milder conditions with shorter adhesion times compared to conventional high-temperature, long-duration curing processes
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 adhesive sheet exhibits high adhesive power to both vulcanized and unvulcanized rubber, allowing for rapid and efficient adhesion at lower temperatures and in shorter times, with improved film strength and interfacial bonding, enhancing the adhesion process without the need for surface treatment.
Implementation Method 1
promotes strong adhesion to rubber through thiol-ene reactions and chemical bonding
Implementation Method 2
a radical generator
Implementation Method 3
an amine-based catalyst
Data Source
AI summary
An adhesive sheet includes an adhesive composition layer. The adhesive composition layer is formed using a composition including a polythiol compound, a compound having plural epoxy groups, a radical generator and an amine-based catalyst. The ratio (Ep/SH (epoxy groups/thiol groups ratio)) of a total molar number (Ep) of epoxy groups contained in the compound having plural epoxy groups to a total molar number (SH) of thiol groups contained in the polythiol compound is higher than 0.20 but lower than 1.00.