Waterproof Silicone Rubber Composition for Wire Harness Sealing
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Solution Overview
Problem
Wire harnesses exposed to water, such as those in engine rooms, face reduced waterproofing performance due to peeling off of sealants when flexed or bent, leading to compromised sealing.
Innovation Solution
A silicone rubber composition containing thermosetting silicone rubber with Shore A hardness of not more than 25 and breaking strength of at least 5.0 MPa, incorporating a vinyl group-containing compound, is used in waterproofing parts of wire harnesses to maintain sealing even under flexing and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional waterproofing sealants are used in wire harnesses, then waterproofing function is provided, but the sealants peel off when flexing and bending occur, reducing waterproofing performance
Solution Approach 1:
The patent changes the physical and chemical parameters of the silicone rubber composition, specifically controlling Shore A hardness to not more than 25 and breaking strength to at least 5.0 MPa. This parameter optimization allows the material to maintain flexibility while resisting peeling, resolving the contradiction between waterproofing reliability and peeling resistance
Solution Approach 2:
The patent uses a composite material system consisting of thermosetting silicone rubber combined with specific additives and fillers. This composite structure provides both the flexibility needed to prevent peeling and the strength needed to maintain waterproofing performance under flexing and bending conditions
2Adaptability or versatility
If the waterproofing material is made softer to prevent peeling during flexing, then flexibility improves, but strength and structural integrity may be compromised
Solution Approach 1:
The patent precisely controls the Shore A hardness parameter to not more than 25, which provides sufficient flexibility for flexing and bending applications. Simultaneously, the breaking strength is maintained at least 5.0 MPa through optimized composition and curing conditions, resolving the contradiction between flexibility and strength
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 ensures maintained waterproofing performance by providing flexibility and strength, preventing cracks and clearances, and is effective in sealing even when subjected to flexing and bending forces.
Implementation Method 1
contains thermosetting silicone rubber and has Shore A hardness of not more than 25 after being cured and breaking strength of at least 5.0 MPa after being cured
Implementation Method 2
A molar ratio (a:b) between a vinyl group (a) of the vinyl group-containing compound and a hydrosilyl group (b) in the thermosetting silicone rubber
Data Source
AI summary
A silicone rubber composition for waterproofing which is capable of maintaining waterproofing performance even if flexing and bending occur; a silicone rubber molded body for waterproofing; and a wire harness. This silicone rubber composition for waterproofing includes a thermosetting silicone rubber, has a Shore A hardness of not more than 25 after being cured, and has breaking strength of at least 5.0 MPa after being cured. The silicone rubber composition for waterproofing is used in a waterproofing part of a wire harness. It is preferable that a vinyl group-containing compound be included in addition to the thermosetting silicone rubber. A vinyl group-containing compound may be a monofunctional vinyl group-containing compound.