Acrylic Rubber Composition for Low-Temperature 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 temperatures while maintaining roll processability and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

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

Engineering Contradiction:
Improvelow temperature resistanceVSAvoidroll processability
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the glass transition point of acrylic rubber to -42°C or lower, and by optimizing the filler composition (silica 5-12.5 parts, graphite 5-15 parts per 100 parts rubber). This resolves the contradiction by adjusting material parameters to achieve both low temperature resistance and acceptable roll processability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining ultracold-resistant acrylic rubber with specific ratios of silica and graphite fillers. This composite approach enhances low temperature performance while the graphite component specifically improves roll processability, resolving the trade-off between temperature resistance and manufacturability

Inventive Principle:
Principle #40Composite materials

2Temperature

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

Engineering Contradiction:
Improvelow temperature resistanceVSAvoidadhesion
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent changes material parameters by selecting acrylic rubber with glass transition point of -42°C or lower and optimizing the filler ratio (particularly graphite at 5-15 parts), which maintains adhesion strength while achieving superior low temperature resistance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite formulation combining ultracold-resistant acrylic rubber with silica and graphite creates a material that maintains adhesion properties through the rubber matrix while the filler combination enhances low temperature performance without sacrificing bonding strength

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional acrylic rubber composition is used, then the roll processability is acceptable, but the low temperature resistance is insufficient

Engineering Contradiction:
Improveroll processabilityVSAvoidlow temperature resistance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent improves low temperature resistance by changing the glass transition point parameter to -42°C or lower while maintaining conventional filler ratios that ensure acceptable roll processability, thus resolving the contradiction between manufacturability and temperature performance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3677643B1Acrylic rubber composition
Publication Date: 2023.11.15 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.