Flame-Retardant Gasket Rubber Composition With Better Mold Release
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Solution Overview
Problem
Hydrated metal oxides used as flame retardants in ethylene-α-olefin-non-conjugated diene copolymer rubber compositions adhere strongly to manufacturing equipment, reducing processability and increasing hardness, making them unsuitable for sealing materials. Additionally, high amounts of these oxides require increased usage of processing aids, which can reduce flame retardancy.
Innovation Solution
Incorporating an alkyl-modified silane coupling agent in a predetermined ratio with aluminum hydroxide reduces adhesion to molds and suppresses hardness increases, while including the silane coupling agent or a plasticizer at specific contents achieves appropriate hardness without compromising flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of hydrated metal oxide is added to impart flame retardancy, then flame retardancy is improved, but adhesion to manufacturing equipment increases and processability deteriorates
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the hydrated metal oxide and the rubber matrix. This coupling agent modifies the surface of the hydrated metal oxide particles, reducing their polarity and hydrophilicity. As a result, the modified filler interacts more compatibly with the hydrophobic rubber matrix, significantly reducing adhesion to manufacturing equipment like molds and kneaders while maintaining the flame retardant function of the hydrated metal oxide.
2Reliability
If a large amount of hydrated metal oxide is added to impart flame retardancy, then flame retardancy is improved, but hardness increases and suitability for sealing materials deteriorates
Solution Approach 1:
The silane coupling agent acts as a intermediary that creates a compatible interface between the hydrated metal oxide and rubber matrix. This compatibility prevents the filler particles from acting as hard, rigid inclusions that would increase overall hardness. Instead, the modified filler is better integrated into the rubber matrix, maintaining the softness and elasticity required for sealing materials while preserving flame retardancy.
3Ease of manufacture
If processing aids are increased to reduce adhesion to molds, then adhesion is reduced, but the amount of flame retardant decreases and flame retardancy deteriorates
Solution Approach 1:
The silane coupling agent serves as a functional intermediary that simultaneously addresses both mold releasability and flame retardancy. By modifying the surface properties of the hydrated metal oxide, it provides inherent mold release properties without requiring additional processing aids. This eliminates the need to trade off between processing aid quantity and flame retardant quantity, as the coupling agent's surface modification effect provides both benefits concurrently.
4Reliability
If halogen-based flame retardants are used to achieve high flame retardancy, then flame retardancy is improved, but environmental pollution increases due to toxic and corrosive halogen gases
Solution Approach 1:
The patent extracts and eliminates the harmful halogen-based flame retardants from the composition, replacing them with environmentally benign hydrated metal oxides such as aluminum hydroxide or magnesium hydroxide. These non-halogen flame retardants decompose to form water and metal oxides rather than toxic halogen gases, thereby maintaining effective flame retardancy while eliminating environmental pollution and health hazards associated with halogen release during combustion.
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 resulting flame-retardant rubber composition exhibits excellent flame retardancy, low environmental impact, good releasability, and physical properties suitable for sealing materials, meeting V-0 grade in the UL94 standard.
Implementation Method 1
Incorporating an alkyl-modified silane coupling agent in a predetermined ratio with aluminum hydroxide reduces adhesion to molds and suppresses hardness increases
Implementation Method 2
aluminum hydroxide...function as flame retardants
Implementation Method 3
hydrated metal oxides...function as flame retardants
Data Source
AI summary
Provided is a flame-retardant rubber composition including an ethylene-α-olefin-non-conjugated diene copolymer, aluminum hydroxide, an alkyl-modified silane coupling agent, and a hydrocarbon-based plasticizer. An amount of the aluminum hydroxide is 60 mass % or more of the flame-retardant rubber composition, a total amount of the alkyl-modified silane coupling agent and the hydrocarbon-based plasticizer is 8 mass % or less of the flame-retardant rubber composition, and an amount of the alkyl-modified silane coupling agent is 5 mass % or more of the aluminum hydroxide. The flame-retardant rubber composition has excellent flame retardancy, physical properties suitable as a sealing material, and low environmental impact.