Self-Lubricating Silicone Elastomer Composition Without Oil Bleeding
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Solution Overview
Problem
Existing silicone elastomeric materials exhibit high coefficients of friction, leading to issues such as blade detachment and noise during windshield wiping, and oil bleeding results in mechanical property degradation and mold fouling, necessitating improved compositions.
Innovation Solution
A self-lubricating silicone elastomer composition comprising 50 to 75% polydiorganosiloxane polymer with 0.01 to 0.1% alkenyl or alkynyl content, 3 to 15% polydiorganosiloxane polymer with ≥0.5% alkenyl or alkynyl content, 10 to 35% reinforcing filler, and a peroxide or hydrosilylation catalyst, which cures to form a material with a low coefficient of friction and avoids oil bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone elastomeric materials are used for wiper blades, then temperature resistance and chemical stability are improved, but the coefficient of friction becomes unacceptably high causing blade detachment and noise
Solution Approach 1:
The patent creates a composite material by incorporating PTFE particles (0.1-5.0 phr) into the silicone elastomer matrix. This composite structure combines the temperature resistance and chemical stability of silicone with the low friction properties of PTFE, achieving a balanced performance that resolves the contradiction between reliability and friction.
Solution Approach 2:
The patent applies local quality by concentrating the lubricating function in specific PTFE particle regions within the elastomer matrix. The PTFE particles are distributed to create localized low-friction zones at the contact surface, while the bulk silicone material maintains its temperature resistance and structural integrity.
2Object-affected harmful factors
If PTFE coatings are applied to reduce friction, then the coefficient of friction is improved, but the coating wears off over time reducing frictional characteristics
Solution Approach 1:
The patent merges the lubricating function directly into the bulk elastomer material by incorporating PTFE particles during compounding. This integration ensures that low-friction properties are inherent to the material itself rather than being a separate surface coating, so when surface material wears, fresh PTFE particles are exposed from within, maintaining consistent friction characteristics throughout the service life.
Solution Approach 2:
The PTFE-containing elastomer exhibits self-service by automatically replenishing its low-friction surface properties through wear. As the elastomer surface wears during use, embedded PTFE particles are gradually exposed, continuously providing lubrication without requiring external re-coating or maintenance.
3Object-affected harmful factors
If self-bleeding elastomers are used to create lubricious surfaces, then friction is reduced, but liquid lubricants bleed out coating the windscreen surface and obscuring driver view
Solution Approach 1:
The patent uses small, inert PTFE particles (1-50 μm) as disposable lubricating elements distributed throughout the elastomer. These particles provide lubrication through physical contact and shear mechanisms rather than liquid bleeding, eliminating the harmful effect of lubricant migration while maintaining low-friction performance throughout the material's service life.
4Object-affected harmful factors
If PTFE powders are added to reduce friction, then the coefficient of friction is improved, but particle size and distribution affect mechanical properties
Solution Approach 1:
The patent optimizes the PTFE particle size parameter (1-50 μm range) and concentration parameter (0.1-5.0 phr) to achieve the best balance between friction reduction and mechanical property retention. This parameter optimization ensures that PTFE particles are small enough to distribute uniformly without creating stress concentration points, while maintaining sufficient elastomer matrix continuity to preserve tensile strength, elongation, and tear resistance.
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 a post-cured kinetic coefficient of friction of ≤0.8, reducing friction-related issues and maintaining mechanical stability without secondary coating processes, enhancing longevity and ease of molding.
Implementation Method 1
silicone elastomer compositions which cross-link by addition (sometimes referred to as hydrosilylation) cure or peroxide radical cure
Implementation Method 2
silicone elastomer compositions which cross-link by addition (sometimes referred to as hydrosilylation) cure
Implementation Method 3
self-lubricating silicone elastomers have been developed by e.g. introducing polytetrafluoroethylene (PTFE) powders
Data Source
AI summary
Provided herein is a self-lubricating silicone elastomer composition and a self-lubricating, elastomeric material made therefrom which has a low coefficient of friction and avoids the need for “self-bleeding”. The self-lubricating silicone elastomer composition comprises: (i) 50 to 75% by weight of one or more polydiorganosiloxane polymer(s) containing from 0.01 to 0.1% by weight of alkenyl and/or alkynyl content; (ii) 3 to 15% by weight of a polydiorganosiloxane polymer having ≥0.5% by weight of alkenyl or alkynyl content; (iii) 10 to 35% by weight of reinforcing filler; and either or both of (iv) a peroxide catalyst; or (v) a hydrosilylation catalyst package.