Self-Adhesive Silicone Rubber Composition Bonding Thermoplastics
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Solution Overview
Problem
Existing addition curable silicone rubber compositions fail to achieve sufficient bonding with general thermoplastic resins like ABS, PC, PE, PP, PBT, PET, acrylic resins, PA, aromatic PA, PPO, PPS, and urethane resins within a brief molding step, requiring resin modification and additional steps, which increases costs and can lead to quality issues.
Innovation Solution
An addition curable self-adhesive silicone rubber composition comprising 100 parts of an organopolysiloxane with silicon-bonded alkenyl groups, 0.2 to 30 parts of an organohydrogenpolysiloxane with three or more silicon-bonded hydrogen atoms, and a catalytic amount of a platinum-based addition reaction catalyst, with a molar ratio of SiH functional groups to alkenyl groups ranging from 0.8 to 5.0, which allows bonding with a wide variety of metals and resins without releasing harmful chemicals like benzene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heat-curable silicone rubber compositions of the addition reaction type are used for bonding to general thermoplastic resins, then the molding process is simplified, but sufficient bond strength cannot be achieved within a brief molding step
Solution Approach 1:
The patent changes the chemical parameters of the silicone rubber composition by incorporating specific organohydrogenpolysiloxane compounds with controlled SiH group content and molecular weight, enabling the composition to bond effectively with general thermoplastic resins within a brief molding step while maintaining sufficient bond strength
Solution Approach 2:
The patent creates a composite silicone rubber composition by combining organopolysiloxane with alkenyl groups, organohydrogenpolysiloxane with specific SiH content, and a platinum catalyst, forming a multi-component system that achieves both rapid curing and strong bonding to thermoplastic resins
2Strength
If resin modification is performed to achieve bonding ability, then adhesion to silicone rubber is improved, but additional steps and extra cost are required
Solution Approach 1:
The patent enables the silicone rubber composition itself to provide the bonding functionality through its inherent chemical composition (organohydrogenpolysiloxane with SiH groups), eliminating the need for external resin modification processes while achieving sufficient adhesion to thermoplastic resins
Solution Approach 2:
The patent creates a universal silicone rubber composition that can bond to multiple types of materials (metals, organic resins, glass, and general thermoplastic resins) without requiring material-specific modifications, simplifying the manufacturing process across different applications
3Strength
If resin modification is performed to achieve bonding ability, then adhesion to silicone rubber is improved, but quality alteration may occur
Solution Approach 1:
The silicone rubber composition provides its own bonding capability through the organohydrogenpolysiloxane component, eliminating the need to modify the thermoplastic resin and thereby preserving the resin's original quality and avoiding potential quality alterations
4Productivity
If self-adhesive silicone rubber composition is used, then priming or coating step is eliminated and operating time is shortened, but bonding to general thermoplastic resins is insufficient
Solution Approach 1:
The patent optimizes the chemical parameters of the self-adhesive silicone rubber composition by controlling the SiH group content (0.003 to 0.017 mol/g), molecular weight, and structure of the organohydrogenpolysiloxane, enabling both rapid curing (short operating time) and strong bonding to thermoplastic resins
Solution Approach 2:
The patent formulates a multi-component composite system combining organopolysiloxane with alkenyl groups, organohydrogenpolysiloxane with controlled SiH content, and platinum catalyst, creating a composition that cures rapidly while achieving sufficient bond strength to thermoplastic resins without requiring priming or coating steps
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 cures into a tight bond with metals, organic resins, and glass, enabling efficient integrally molded articles with improved adhesion and reduced processing time, while avoiding the need for resin modification and associated costs.
Implementation Method 1
a catalytic amount of a platinum-based addition reaction catalyst
Implementation Method 2
molar ratio of SiH functional groups to alkenyl groups ranging from 0.8 to 5.0
Data Source
AI summary
An addition curable self-adhesive silicone rubber composition comprising (A) an organopolysiloxane containing at least two alkenyl groups, (B) an organohydrogenpolysiloxane containing at least three SiH groups, (C) an aromatic ring-free organohydrogenpolysiloxane containing at least two SiH groups, and (F) an addition reaction catalyst, with a SiH/alkenyl molar ratio ranging from 0.8 to 5.0, is briefly moldable and cures to various metals and organic resins.