Polycarbonate Silicone Bonding via Modified Siloxanes
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Solution Overview
Problem
Polycarbonate and polyester blends have rigid surfaces that can be irritating to users, and existing methods fail to achieve strong bonding between these surfaces and over-molded silicone rubber, necessitating a cost-effective solution for enhancing bond strength.
Innovation Solution
Molded polycarbonate substrates are modified with polydimethyl siloxanes containing acrylate, hydroxyl, or epoxy groups, which are then bonded with a mixture of polysiloxanes and platinum or rhodium-based catalysts to create a cured silicone rubber layer with improved peel strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cured silicone rubber is over-molded onto polycarbonate surfaces, then the surface becomes softer and less irritating to users, but the bond strength between the silicone rubber and polycarbonate surface is insufficient
Solution Approach 1:
The invention modifies the chemical composition parameters of the polycarbonate substrate by incorporating silane coupling agents and surface treatment agents. These parameter changes create a chemically active surface layer that enhances the bonding interface between the rigid polycarbonate and the soft silicone rubber, simultaneously achieving both softness and strong adhesion.
Solution Approach 2:
The invention creates a composite structure by forming a transitional bonding layer on the polycarbonate surface through chemical modification. This bonding layer acts as an intermediate phase that is compatible with both the polycarbonate substrate and the silicone rubber overmold, resulting in a multi-phase composite material system with improved interfacial adhesion.
2Ease of manufacture
If existing bonding methods are used for silicone rubber to polycarbonate, then the process is simple, but the bond strength is insufficient and requires more costly solutions
Solution Approach 1:
The invention applies preliminary surface modification treatment to the polycarbonate substrate before the silicone rubber overmolding process. By pre-incorporating silane coupling agents and performing surface activation, the bonding capability is enhanced in advance, allowing the subsequent overmolding to proceed with standard processes while achieving superior bond strength.
Solution Approach 2:
The invention introduces silane coupling agents as intermediary substances that mediate the bonding between polycarbonate and silicone rubber. These intermediaries form chemical bridges at the interface, enabling strong adhesion without requiring complex processing steps or additional bonding operations.
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 modified substrates exhibit enhanced bonding strength between the polycarbonate substrates and silicone rubber, achieving peel strengths of 1.80 kg/mm or greater, with improved durability and suitability for various applications such as automotive and medical devices.
Implementation Method 1
the one or more polycarbonate resins or blends of polycarbonate and polyester resins contain the modified polydimethyl siloxanes in sufficient amount such that the peel strength of the cured silicone rubber from the molded substrates after curing is enhanced
Implementation Method 2
applying a mixture comprising one or more polysiloxanes containing one or more unsaturated groups, one of more polysiloxanes containing one or more S—H groups; and one or more platinum or rhodium based catalysts to the surface or a portion thereof of the substrate; and exposing the mixture to conditions such that a cured silicone rubber layer is disposed on the surface
Data Source
AI summary
Articles comprising: a molded substrate comprising one or more polycarbonate resins or blends of polycarbonate and polyester resins containing polydimethyl siloxanes modified with one or more of acrylate, hydroxyl or epoxy groups and disposed on the surface or a portion of the surface of the substrate is a cured silicone rubber; wherein the one or more polycarbonate resins or blends of polycarbonate and polyester resins contain the modified polydimethyl siloxanes in sufficient amount such that the peel strength is increased. Compositions comprising one or more polycarbonate resins or blends of polycarbonate and polyester resins containing polydimethyl siloxanes modified with one or more of acrylate, hydroxyl or epoxy groups in an amount of about 0.1 to less than 1.0 percent by weight. Methods for preparing the articles are disclosed.