Hydrotreated Naphthenic Rubber Compositions for Cold Flexibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Air brake hoses made from ethylenepropylene-diene copolymer rubber compounds become brittle and exhibit low temperature embrittlement below -65°C, leading to failure, necessitating materials with improved extreme low temperature flexibility.
Innovation Solution
A rubber composition incorporating severely hydrotreated naphthenic distillate up to 30% by weight, combined with sulfur curatives and curing accelerators, such as mercaptobenzothiazole, to enhance cold flexibility down to -73°C or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethylenepropylene-diene copolymer rubber compound is used for air brake hoses, then the material provides resistance to stress cracking by zinc chloride and environmental resistance, but the material becomes brittle and exhibits low temperature embrittlement below -65°C
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber compound by incorporating severely hydrotreated naphthenic distillate (0-30 parts by weight per 100 parts rubber) and specific curative systems (sulfur, nitrogen-containing curatives, metal oxides) to modify the polymer's low-temperature behavior while maintaining stress crack resistance
Solution Approach 2:
The patent creates a composite rubber material system combining ethylenepropylene-diene copolymer base rubber with hydrotreated naphthenic distillate plasticizer and multi-component curative system to achieve synergistic properties of both stress crack resistance and low-temperature flexibility
2Ease of operation
If conventional naphthenic process oil is used as plasticizer, then the rubber compound achieves processability and flexibility, but the articles become brittle at temperatures below -65°C
Solution Approach 1:
The patent changes the physical and chemical parameters of the plasticizer by using severely hydrotreated naphthenic distillate with controlled viscosity (10-100 cSt at 40°C) and chemical composition to achieve both processability and low-temperature flexibility without brittleness
Solution Approach 2:
The hydrotreated naphthenic distillate acts as an intermediary substance that mediates between the rubber polymer chains, providing adequate lubrication for processing while maintaining polymer chain mobility at low temperatures to prevent brittleness
Data Source
AI summary
A composition includes at least one natural or synthetic rubber material, a severely hydrotreated naphthenic distillate incorporated in amount equal to or less than 30% by weight of the composition, and a sulfur curative. After curing, the composition provides acceptable cold flexibility at a temperature lower than -60 deg C, at a temperature as low as -68 deg C, or even at a temperature as low as -73 deg C. In some aspects, the at least one natural or synthetic rubber material is a synthetic rubber such as, but not limited to, an ethylenepropylene-diene copolymer rubber. In some cases, where used, the ethylenepropylene-diene copolymer rubber is selected from the group consisting of ethylene-propylene-cyclopentadiene terpolymer, ethylene-propylene ethylidene norbornene terpolymer, ethylene-propylene-I, and mixtures thereof.