Fuel Hose Laminate Composition for Stable Layer Adhesion
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Solution Overview
Problem
Existing fuel hoses experience adhesion issues between a polyol-crosslinked fluororubber inner layer and a hydrin rubber outer layer due to scorching (fading) at the adhesive interface, particularly when stored in a raw rubber state after extrusion, leading to decreased bonding strength.
Innovation Solution
A fuel hose design with an inner layer composed of a crosslinked fluororubber containing polyol crosslinking agents and triallyl isocyanurate, and an outer layer composed of hydrin rubber with monoglycerides having 10-22 carbon atoms, carbon black with specific DBP absorption, and an acid acceptor like hydrotalcite, which enhances adhesion by preventing scorching and promoting crosslinking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If calcium hydroxide is used as a crosslinking accelerator in polyol-crosslinked fluororubber inner layer, then crosslinking efficiency is improved, but scorching (fading) occurs at the adhesive interface when stored in raw rubber state
Solution Approach 1:
A silicone oil-modified polyisocyanate crosslinking agent is introduced as an intermediary substance between the polyol-crosslinked fluororubber inner layer and the hydrin rubber outer layer. This crosslinking agent reacts with both the polyol groups in the fluororubber and the hydroxyl groups in the hydrin rubber, forming a bridging crosslinked structure that prevents direct harmful interaction between calcium hydroxide and the rubber layers during storage, thereby eliminating scorching while maintaining crosslinking efficiency
Solution Approach 2:
The invention changes the chemical parameters of the crosslinking system by selecting a specific silicone oil-modified polyisocyanate crosslinking agent with controlled reactivity. This parameter change allows the crosslinking reaction to proceed efficiently when needed while reducing unwanted side reactions during storage, thus resolving the contradiction between crosslinking efficiency and storage stability
2Ease of manufacture
If the laminate is stored in a raw rubber state after extrusion, then manufacturing flexibility is improved, but adhesion between inner layer and outer layer decreases due to scorching
Solution Approach 1:
The silicone oil-modified polyisocyanate crosslinking agent is pre-introduced into the rubber composition before extrusion. During storage in raw rubber state, this crosslinking agent preliminarily forms protective crosslinked structures at the adhesive interface that prevent scorching. When the hose is later crosslinked, the adhesion strength is already established and maintained, thus allowing manufacturing flexibility without compromising adhesion
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 solution effectively prevents scorching at the adhesive interface, ensuring excellent adhesion between the inner and outer layers even when stored in a raw rubber state, maintaining structural integrity and performance.
Implementation Method 1
The monoglyceride reduces scorching (fading) of the polyol-crosslinked fluororubber due to calcium hydroxide at the adhesive interface between the inner layer and the outer layer
Implementation Method 2
the inner layer is composed of a crosslinked body of a rubber composition containing the following (A) to (E)
Data Source
AI summary
A fuel hose has an inner layer in a tubular shape and an outer layer provided in contact with an outer circumferential surface of the inner layer, and the inner layer is composed of a crosslinked body of a rubber composition containing the following (A) to (E), and the outer layer is composed of a crosslinked body of a rubber composition containing the following (F) to (G):(A) polyol-crosslinked fluororubber(B) polyol crosslinking agent(C) calcium hydroxide(D) triallyl isocyanurate(E) peroxide crosslinking agent(F) hydrin rubber(G) monoglyceride having an aliphatic hydrocarbon group having 10 or more and 22 or less carbon atoms.