Oil-Bleed Self-Bonding LSR for Primerless Thermoplastic Bonding
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Solution Overview
Problem
Existing methods for bonding addition-cured liquid silicone rubber (LSR) to thermoplastics require primers, which complicate the process and can be inefficient, and incorporating oil-bleed functionality can negatively impact adhesion.
Innovation Solution
A self-bonding liquid silicone rubber composition combining alkyl-group-containing silicone oil, an organosilicon compound with a polyvalent aromatic group, and an aromatic compound without a siloxane group, enabling primer-less bonding to thermoplastic substrates with time-lapse oil bleed for lubricity and avoiding delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a primer is applied to enable bonding between LSR and thermoplastics, then adhesion strength is improved, but process complexity and manufacturing time increase
Solution Approach 1:
The patent combines the bonding function and oil-bleed function into a single LSR composition without requiring separate primer application. The composition includes organosilicon compounds with phenylene groups and hydrosilyl groups that enable direct bonding to thermoplastics while maintaining oil-bleed capability for lubricity.
Solution Approach 2:
The LSR composition is designed to perform multiple functions simultaneously: bonding to thermoplastics, providing lubricity through oil-bleed, and enabling direct molding without primer. This multi-functional formulation eliminates the need for separate primer application while maintaining adhesion strength.
2Ease of operation
If oil-bleed additives are incorporated into LSR to provide lubricity, then release from molds is improved, but adhesion to thermoplastic substrates deteriorates
Solution Approach 1:
The patent uses organosilicon compounds with specific structures (containing phenylene groups and hydrosilyl groups) as intermediaries that mediate between the oil-bleed function and adhesion function. These compounds enable the LSR to bond to thermoplastics while maintaining the oil-bleed capability for lubricity, resolving the conflict between the two functions.
Solution Approach 2:
The LSR composition is formulated as a composite material containing multiple components including organosilicon compounds, silicone oils, and other additives that work together to provide both adhesion and oil-bleed functionality simultaneously, rather than using a single-component system where these functions would be mutually exclusive.
3Strength
If bonding agents are added to LSR to improve adhesion to thermoplastics, then bonding performance is improved, but formulation complexity increases
Solution Approach 1:
The patent modifies the chemical parameters of the LSR formulation by incorporating specific organosilicon compounds with defined molecular structures (containing phenylene groups and hydrosilyl groups). These parameter changes enable improved bonding performance while maintaining a relatively simple formulation structure that can be integrated into existing LSR manufacturing 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 composition achieves strong bonding to thermoplastic substrates at high temperatures without primers, maintaining adhesion and reducing mold fouling through controlled oil migration.
Implementation Method 1
The alkyl-group-containing silicone oil, on the other hand, can migrate to the surface over time due to its immiscibility with vulcanized silicone rubber to generate a thin layer of oil on rubber surface, providing lubricity.
Implementation Method 2
The combination of OSC and DAC provides strong bonding between silicone rubber and the substrate even at relatively high temperatures, such as 120° C., to avoid possible delamination issues during the molding processes.
Data Source
AI summary
The present invention relates to an oil-bleed self-bonding liquid silicone rubber composition having both self-bonding and self-lubricating capabilities. The oil-bleed self-bonding liquid silicone rubber composition exhibits self-bonding capability in particular to substrates that contain residual hydroxyl groups or other residual hydrosilyl-reacting groups on their surface, including polycarbonate, polyester, polyamide, polysulfone, polyurethane, phenolic resin, epoxy resin, cellulose, glass and the mixture thereof.