Rubber Composition for Refrigerant Hose Adhesion and Compression Set
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Solution Overview
Problem
Existing rubber compositions for refrigerant-transporting hoses suffer from deteriorated compression set resistance, adhesiveness between resin and rubber layers, and maintaining strength of the reinforcing layer, leading to reduced product life.
Innovation Solution
A rubber composition with a specific formulation including 1 to 15 parts by mass of phenolic resin and 0.05 to 1 part by mass of fatty acid, relative to 100 parts by mass of a rubber component containing a bromide of copolymer rubber, halogenated butyl rubber, and butyl rubber, which suppresses deterioration of the fiber layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rubber composition containing a butyl-based rubber, a fatty acid (e.g., stearic acid) as a processing aid, and a resin crosslinking agent is used, then the rubber layer can be formed with good processability, but the fatty acid and resin crosslinking agent deteriorate the synthetic resin fiber in the reinforcing layer, decreasing the strength maintaining property
Solution Approach 1:
The patent applies parameter changes by precisely controlling the content of fatty acid to 0.05-1 part by mass and phenolic resin to 1-15 parts by mass relative to 100 parts by mass of rubber component. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where sufficient processing aid is present for manufacturability while the amount is limited enough to prevent fiber deterioration.
Solution Approach 2:
The patent applies local quality by differentiating the functional roles of different components in the rubber composition. The fatty acid serves locally as a processing aid for rubber compound preparation, while the phenolic resin provides crosslinking function. By optimizing their respective contents independently, the patent ensures good processability in the rubber layer formation while minimizing harmful effects on the adjacent fiber layer.
2Strength
If a rubber composition containing a butyl-based rubber and a resin crosslinking agent is used, then the rubber layer can be formed with good crosslinking properties, but the compression set resistance of the rubber layer deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the phenolic resin content to 1-15 parts by mass relative to 100 parts by mass of rubber component. This specific quantity range achieves sufficient crosslinking for good rubber layer formation while preventing excessive crosslinking that would deteriorate compression set resistance. The parameter optimization resolves the contradiction between crosslinking quality and compression set performance.
3Strength
If a rubber composition containing a butyl-based rubber and a resin crosslinking agent is used, then the rubber layer can be formed with good adhesion to the resin layer, but the adhesiveness between the resin layer and rubber layer deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the phenolic resin content within 1-15 parts by mass relative to 100 parts by mass of rubber component. This optimized quantity ensures sufficient adhesion promoter is present for good bonding between resin and rubber layers, while preventing excess phenolic resin that would migrate and deteriorate the adhesiveness. The quantitative optimization resolves the contradiction between initial adhesion and sustained adhesiveness.
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 rubber composition achieves excellent compression set resistance, adhesiveness between resin and rubber layers, and maintains the strength of the reinforcing layer, thereby enhancing the product life of the hose.
Implementation Method 1
a decrease of an amount of a fatty acid or a phenolic resin that is a resin crosslinking agent in a rubber composition can suppress deterioration of a fiber layer
Implementation Method 2
a rubber composition including: from 1 to 15 parts by mass of a phenolic resin; and 0.05 parts by mass or more and less than 1 part by mass of a fatty acid, relative to 100 parts by mass of a rubber component
Implementation Method 3
adhesiveness between a resin layer and the rubber layer on the innermost layer
Data Source
AI summary
An object of the present invention is to provide a rubber composition excellent in compression set resistance of the obtained rubber layer, adhesiveness between a resin layer and the rubber layer, and a maintaining property of strength of a reinforcing layer adjacent to the rubber layer. A rubber composition including: from 1 to 15 parts by mass of a phenolic resin; and 0.05 parts by mass or more and less than 1 part by mass of fatty acid, relative to 100 parts by mass of a rubber component containing from 30 to 100 parts by mass of a bromide of a copolymer rubber of an isomonoolefin and a p-alkylstyrene, from 0 to 70 parts by mass of a halogenated butyl rubber, and from 0 to 70 parts by mass of a butyl rubber, and a multilayer structure and a hose containing the same.