Acrylic Rubber Composition for Cold-Resistant Bonded Piston Seals

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Solution Overview

Problem

Conventional acrylic rubber compositions used in bonded piston seals face challenges in low temperature environments, particularly below -30°C, due to their low glass transition point, which affects roll processability and adhesion.

Innovation Solution

An acrylic rubber composition incorporating 5 to 12.5 parts by weight of silica and 5 to 15 parts by weight of graphite as fillers, based on ultracold-resistant acrylic rubber with a glass transition point of -42°C or lower, enhances the seals' performance in low temperature environments while maintaining roll processability and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acrylic rubber with low glass transition point is used to withstand low temperature environment, then cold resistance is improved, but roll processability and adhesion deteriorate

Engineering Contradiction:
Improvecold resistanceVSAvoidroll processability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameters of the acrylic rubber by incorporating specific copolymer components (acrylonitrile, vinyl chloroacetate, allyl chloroacetate) in controlled ratios. This modifies the glass transition point to -42°C or lower while maintaining processing properties through the balanced composition design

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite rubber material by combining multiple polymer components (acrylic rubber base, copolymer components) with specific fillers (silica, graphite) and curing agents. This composite structure achieves both low-temperature resistance and improved roll processability through synergistic material interactions

Inventive Principle:
Principle #40Composite materials

2Reliability

If acrylic rubber with low glass transition point is used to withstand low temperature environment, then cold resistance is improved, but adhesion deteriorates

Engineering Contradiction:
Improvecold resistanceVSAvoidadhesion
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent modifies the chemical parameters by incorporating functional groups (vinyl chloroacetate, allyl chloroacetate) that enhance adhesion properties while maintaining the low glass transition point through controlled copolymerization ratios

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite formulation includes silica and graphite fillers that improve adhesion, along with specific curing agents that create strong crosslinked structures. This composite approach maintains cold resistance while significantly improving adhesion strength

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional acrylic rubber composition is used, then roll processability is maintained, but cold resistance below -30°C is insufficient

Engineering Contradiction:
Improveroll processabilityVSAvoidcold resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent achieves superior cold resistance by lowering the glass transition point to -42°C or lower through specific copolymer composition design, while the controlled formulation maintains acceptable roll processability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The use of composite materials with specific filler combinations (silica 5-12.5 parts, graphite 5-15 parts per 100 parts rubber) enhances cold resistance without significantly compromising roll processability

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS11407879B2Acrylic rubber composition
Publication Date: 2022.08.09 NOK CORP

AI summary

An acrylic rubber composition comprising 5 to 12.5 parts by weight of silica and 5 to 15 parts by weight of graphite as fillers, based on 100 parts by weight of ultracold-resistant acrylic rubber having a glass transition point Tg of −42° C. or less. Due to the use of ultracold-resistant acrylic rubber, the use environment temperature, i.e., −30 to +150° C., is satisfied. In addition, the respective use of specific amounts of silica and graphite as fillers allows the formation of bonded piston seals that have roll processability and adhesion equivalent to or higher than those of the existing seals, and that satisfy compression set characteristics.