Adhesive-Free Rubber-Plastic Bonding via Halogen Oxidation
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Solution Overview
Problem
Current methods for bonding rubber and plastic surfaces during injection molding often require adhesives, which can be inefficient and may not provide sufficient bond strength, especially at higher temperatures.
Innovation Solution
The method involves forming composites by injection molding a diene rubber article with a halogen-oxidized bonding surface, where a polar thermoplastic elastomer is injected to create a strong adhesive-free bond with the rubber surface, using materials like thermoplastic polyurethane, styrene block copolymer, or thermoplastic polyether block amide, with minimal or no adhesive application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesives are used to bond rubber and plastic surfaces, then bond strength is improved, but process complexity and manufacturing steps increase
Solution Approach 1:
The invention extracts and eliminates the adhesive substance from the bonding process. By treating the rubber surface with halogen oxidizing agents to create reactive halogen moieties, the patent achieves direct bonding between rubber and thermoplastic elastomer without requiring any adhesive intermediary, thus simplifying the overall process while maintaining bond strength
Solution Approach 2:
The invention introduces halogen oxidizing agents as a temporary intermediary during surface treatment. These agents create reactive halogen moieties on the rubber surface that facilitate bonding. The halogen treatment acts as a mediator that enables direct bonding without permanent adhesive application, resolving the contradiction between bond strength and process simplicity
2Reliability
If adhesives are applied to bonding surfaces, then bond reliability is improved, but manufacturing time and productivity are reduced
Solution Approach 1:
The invention applies halogen oxidizing treatment to the rubber surface in advance of the bonding operation. This preliminary action creates reactive halogen moieties on the surface that ensure reliable bonding occurs automatically during the injection molding process, eliminating the need for separate adhesive application steps and thereby improving manufacturing productivity while maintaining bond reliability
3Ease of manufacture
If halogen oxidizing treatment is applied to rubber surface, then adhesive-free bonding is achieved, but additional processing steps are required
Solution Approach 1:
The invention merges the halogen oxidizing treatment step with the existing injection molding process workflow. By integrating the surface treatment into the preparation phase before molding, and combining it with the subsequent injection step that creates the bond, the process achieves adhesive-free bonding without requiring entirely separate or complex additional processing equipment, thus improving ease of manufacture while limiting increases in processing complexity
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
This approach achieves a strong bond between rubber and thermoplastic elastomer surfaces, with cohesive failure occurring at temperatures above 25 °C, ensuring at least 80% of the adhesive-free surface area adheres, even without adhesives, enhancing the durability and reliability of bonded components.
Implementation Method 1
the bonding surface has been treated with a halogen oxidizing agent or otherwise has an active halogen moiety
Data Source
Figure 1
AI summary
An injection molded composite comprising a first bonding surface of a diene rubber composition bonded to a second bonding surface of a polar thermoplastic elastomer composition. There may be no more than 25% of the bonding surfaces having an adhesive applied to them or alternatively, no adhesive is applied. Furthermore, the polar thermoplastic elastomer composition was injected against the first bonding surface to form the second bonding surface and the first bonding surface has an active halogen moiety.