Self-Adhesive Silicone Rubber Composition for Thermoplastic Resins
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heat-curable silicone rubber compositions fail to achieve sufficient bonding with general thermoplastic resins like ABS, PPO, PPS, PC, PE, PP, PET, acrylic resins, PA, and urethane resins through a brief molding step, requiring resin modification and additional steps, which increases costs and can lead to quality vulnerabilities.
Innovation Solution
An addition curable self-adhesive silicone rubber composition is developed, comprising organopolysiloxane with silicon-bonded alkenyl groups, organohydrogenpolysiloxane, an organosilicon compound with SiH groups and aromatic rings, reinforcing silica fine powder, and an isocyanate-containing organosilicon compound, which allows bonding with a wide variety of metals and thermoplastic resins without the need for resin modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heat-curable silicone rubber composition is used for bonding with thermoplastic resins, then bonding ability is improved, but the number of manufacturing steps increases and cost increases due to required resin modification
Solution Approach 1:
The patent introduces a specific organosilicon compound containing isocyanate groups and hydrolyzable groups as an intermediary substance. This compound acts as a coupling agent that bonds to both the silicone rubber and the thermoplastic resin, enabling strong adhesion without requiring resin modification or additional priming steps. The intermediary compound resolves the contradiction by providing bonding capability while maintaining process simplicity.
Solution Approach 2:
The patent modifies the chemical composition parameters of the silicone rubber system by incorporating specific ratios of organopolysiloxane, organohydrogenpolysiloxane, and the isocyanate-containing organosilicon compound. By adjusting these compositional parameters, the system achieves strong bonding with thermoplastic resins through a simple one-step molding process, eliminating the need for additional manufacturing steps while maintaining high bond strength.
2Strength
If primer coating method is used to bond silicone rubber to resin, then bonding ability is improved, but the number of manufacturing steps increases and operating time increases
Solution Approach 1:
The patent combines the adhesive function and the silicone rubber matrix into a single integrated composition. The isocyanate-containing organosilicon compound is incorporated directly into the silicone rubber formulation, merging the primer/adhesive function with the rubber matrix. This eliminates the separate primer coating step and reduces operating time while maintaining strong bonding capability.
Solution Approach 2:
The silicone rubber composition itself provides the bonding function through the incorporated isocyanate-containing organosilicon compound. The composition is self-sufficient and does not require external primer applications or additional adhesive steps. The system performs the bonding function inherently, eliminating wasted time associated with multiple coating and curing steps.
3Productivity
If adhesive is added to silicone rubber composition to create self-adhesive type, then the priming step is eliminated and operating efficiency is improved, but bonding ability to certain resins remains insufficient
Solution Approach 1:
The patent creates a composite silicone rubber composition by combining organopolysiloxane, organohydrogenpolysiloxane, reinforcing silica, and specifically an isocyanate-containing organosilicon compound with hydrolyzable groups. This composite material structure provides both the operational efficiency of a self-adhesive system and the strong bonding capability needed for thermoplastic resins, resolving the contradiction between productivity and bonding strength.
Solution Approach 2:
The patent optimizes the compositional parameters by specifying precise amounts of each component, particularly the isocyanate-containing organosilicon compound at 1-20 parts by weight per 100 parts of organopolysiloxane. This parameter optimization ensures sufficient bonding ability to thermoplastic resins while maintaining the simplified self-adhesive process, achieving both high productivity and strong bonding.
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 achieves strong and efficient bonding with metals and organic resins, reducing the number of manufacturing steps, lowering costs, and improving the quality and efficiency of integrally molded articles.
Implementation Method 1
an addition reaction curable silicone rubber composition comprising (A) 100 parts by weight of an organopolysiloxane containing at least two silicon-bonded alkenyl groups in a molecule, (B) 2 parts by weight of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms in a molecule
Implementation Method 2
an addition curable self-adhesive silicone rubber composition which may cure and bond to organic resins such as polyamide, polybutylene terephthalate (PBT), polycarbonate, polyphenylene oxide and polyphenylene sulfide, metals such as iron and aluminum, and various glass materials
Data Source
AI summary
A silicone rubber composition comprising (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups, (B) an organohydrogenpolysiloxane containing at least two SiH groups, but free of aromatic ring, (C) an organosilicon compound containing at least one SiH group and at least one mono- to tetravalent aromatic ring, (D) reinforcing silica, (E) an organic compound containing at least one isocyanate group, and (F) an addition reaction catalyst cures to various metals and organic resins.