Crosslinkable Acrylic Rubber Composition for Thermal Oxidation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods fail to adequately address the thermal oxidative degradation of acrylic rubber, leading to significant softening and hardening degradations in high-temperature environments, which compromises the mechanical strength of crosslinked products.
Innovation Solution
A crosslinkable acrylic rubber composition incorporating a carbamic acid ester group, a carboxyl group, and a phenothiazine-based antioxidant, along with a crosslinking accelerator, which forms a specific crosslinked structure that suppresses thermal oxidative degradation and maintains mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amine-based antioxidants are used to improve heat resistance, then antioxidant effectiveness is improved, but thermal oxidative degradation still occurs leading to softening and hardening
Solution Approach 1:
The patent combines phenothiazine-based antioxidant with acrylic rubber containing both carbamic acid ester groups and carboxyl groups to form a composite material system. This composite approach creates a more effective defense against thermal oxidative degradation than amine-based antioxidants alone, addressing the limitation where conventional antioxidants fail to prevent both softening and hardening degradation.
Solution Approach 2:
The patent changes the chemical structure parameters of the rubber by incorporating specific functional groups (carbamic acid ester and carboxyl groups) that enable crosslinking. This structural modification allows the formation of a crosslinked network that resists thermal oxidative degradation, transforming the rubber's properties to achieve better heat resistance without the degradation issues seen with conventional antioxidants.
2Temperature
If crosslinking structure is formed to improve heat resistance, then thermal stability is improved, but mechanical strength decreases due to thermal oxidative degradation
Solution Approach 1:
The patent creates a composite system where phenothiazine-based antioxidant works synergistically with the crosslinked acrylic rubber structure. This composite material maintains the crosslinked network's thermal stability while the antioxidant component protects against mechanical strength loss from thermal oxidative degradation, resolving the trade-off between heat resistance and mechanical strength retention.
Solution Approach 2:
The phenothiazine-based antioxidant acts as an intermediary substance that protects the crosslinked structure from thermal oxidative attack. It mediates between the crosslinked network and the degrading environment, preventing oxygen and heat from damaging the mechanical integrity of the crosslinked rubber while allowing the crosslinks to maintain thermal stability.
3Reliability
If conventional antioxidants are used, then initial antioxidant protection is provided, but significant softening and hardening degradation occurs under prolonged thermal conditions
Solution Approach 1:
The patent fundamentally changes the antioxidant chemistry from amine-based to phenothiazine-based, which has different thermal stability characteristics. This parameter change in the antioxidant's chemical structure enables sustained protection against thermal oxidative degradation for extended periods, preventing both softening and hardening that occur with conventional antioxidants under prolonged thermal exposure.
Solution Approach 2:
The phenothiazine-based antioxidant serves as a long-lasting intermediary protector between the rubber matrix and thermal oxidative environment. Unlike conventional antioxidants that deplete quickly or fail to prevent degradation, this intermediary maintains its protective function throughout prolonged thermal service, continuously preventing both softening and hardening degradation mechanisms.
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 effectively prevents significant softening and hardening degradations, ensuring the mechanical strength of the acrylic rubber crosslinked product remains intact even under prolonged thermal oxidative conditions.
Implementation Method 1
the carbamic ester group is decomposed by heat and the action of a nitrogen-containing basic organic compound to liberate the amino group
Implementation Method 2
reacts with the active site derived from an α,β-unsaturated carboxylic acid monomer to form a complementary crosslinked structure
Implementation Method 3
suppresses significant softening degradation of the acrylic rubber crosslinked product due to thermal oxidative degradation
Implementation Method 4
the phenothiazine-based antioxidant...exhibits an effect of suppressing significant hardening degradation of the acrylic rubber crosslinked product having the specific crosslinked structure
Data Source
AI summary
A crosslinkable acrylic rubber composition containing: (A) acrylic rubber containing a carbamic acid ester group and a carboxyl group; (B) a phenothiazine-based antioxidant represented by formula [I], wherein R3 is a hydrogen atom, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or an acyl group represented by formula II, wherein R4 is a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and R5 is an aralkyl group having 7 to 20 carbon atoms; and (C) a crosslinking accelerator.