Polyacetal Composition Tribological Enhancement

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Solution Overview

Problem

There is a need for polyacetal compositions with improved tribological properties to enhance their performance in applications where parts are in motion and in contact with other parts, as existing compositions do not adequately address self-lubrication and wear resistance.

Innovation Solution

A polyacetal composition comprising a polyacetal resin, p-aramid particles, and a vinyl-terminated dimethyl siloxane polymer, which provides a low coefficient of friction and wear resistance by combining these components in a specific weight percentage range, optimizing their interaction and physical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polyacetal compositions are used, then good mechanical properties are achieved, but tribological properties (self-lubrication and wear resistance) are insufficient

Engineering Contradiction:
Improvetribological propertiesVSAvoidcomposition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining polyacetal resin with p-aramid particles and vinyl-terminated dimethyl siloxane polymer. This creates a multi-component system where each ingredient contributes specific properties: polyacetal provides mechanical strength, p-aramid particles enhance wear resistance, and the siloxane polymer improves self-lubrication. The synergistic combination resolves the contradiction by achieving superior tribological properties while maintaining reasonable composition complexity through carefully selected weight ratios.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs parameter changes by optimizing the weight percentages of each component: polyacetal resin (85-97 wt%), p-aramid particles (0.1-10 wt%), and vinyl-terminated dimethyl siloxane polymer (0.1-5 wt%). By systematically varying these compositional parameters, the invention achieves optimal tribological performance. This approach resolves the contradiction by finding the precise parameter range that maximizes reliability while controlling composition complexity.

Inventive Principle:
Principle #35Parameter changes

2Strength

If polyacetal resin is used for moving parts, then mechanical strength is achieved, but self-lubricating properties and wear resistance are insufficient

Engineering Contradiction:
Improvemechanical strengthVSAvoidfriction and wear
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by incorporating p-aramid particles and vinyl-terminated dimethyl siloxane polymer as discrete phases within the polyacetal resin matrix. The p-aramid particles provide localized wear resistance at contact points, while the siloxane polymer creates localized low-friction surfaces. This spatial distribution of functional properties resolves the contradiction by maintaining the bulk mechanical strength of polyacetal while adding localized tribological enhancement at critical surfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The vinyl-terminated dimethyl siloxane polymer acts as an intermediary between the polyacetal resin and the contact surface. It migrates to the surface to form a low-friction layer that mediates the interaction between moving parts. The p-aramid particles serve as intermediaries that transfer load and reduce wear at contact points. This intermediary approach resolves the contradiction by decoupling the bulk mechanical strength function from the surface tribological function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 combination of p-aramid particles and vinyl-terminated dimethyl siloxane polymer in the polyacetal composition results in improved tribological properties, offering enhanced self-lubricating and wear-resistant performance compared to conventional polyacetal compositions.

Implementation Method 1

a vinyl-terminated dimethyl siloxane polymer in a amount from 0.1 wt-% to 5 wt-%, based on the total weight of the polyacetal composition, wherein the vinyl-terminated dimethyl siloxane polymer has a viscosity from 0.00015 m 2 s at 25 °C to 0.001 m 2 s at 25 °C

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

p-aramid particles in a amount from 0.1 wt-% to 10 wt-%, based on the total weight of the polyacetal composition

Methodology Applied
Scientific EffectWear resistance: Wear

Data Source

PatentEP2201065B1Polyacetal compositions with improved tribological properties
Publication Date: 2015.03.18 EI DU PONT DE NEMOURS & CO
  • EP2201065B1 patent drawingFigure 1

AI summary

The invention relates to polyacetal compositions comprising (i) a polyacetal resin, (ii) p-aramid particles and (III) a vinyl-terminated dimethyl siloxane polymer and molded products thereof showing improved tribological properties.