Extruded TPV Door Gaskets With Stable Low-Friction Sealing

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Solution Overview

Problem

Conventional washing machine door seal gaskets made from thermoset rubbers are difficult to modify for improved performance due to process limitations and high costs, and they suffer from increased coefficient of friction (COF) after exposure to water and detergents, leading to reduced durability.

Innovation Solution

The use of thermoplastic vulcanizates (TPVs) with a specific composition and Shore A Hardness range, extrusion molded into gaskets with multiple hardness regions, allowing for customizable design and lower tooling costs, and incorporating a non-migratory slip agent to maintain low COF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermoset rubbers are used for gasket manufacturing, then the gasket can be made with good initial sealing properties, but the coefficient of friction increases after exposure to water and detergents, reducing durability

Engineering Contradiction:

Improvesealing performanceVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameter from thermoset rubber to thermoplastic vulcanizate (TPV), which maintains low coefficient of friction even after exposure to water and detergents. This material parameter change resolves the contradiction by providing both good sealing performance and sustained low friction throughout the service life.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite TPV materials that combine the benefits of thermoset materials (sealing properties) with thermoplastic materials (low and stable friction). This composite approach allows the gasket to maintain both reliable sealing and durability over extended service life.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If injection molding process is used for gasket manufacturing, then the gasket can be produced with precise shape, but the cost increases and design modifications become difficult

Engineering Contradiction:

Improvegasket shape precisionVSAvoidmanufacturing cost and design flexibility

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces the injection molding process with an extrusion molding process. This substitution maintains adequate manufacturing precision for gasket shapes while dramatically reducing tooling costs and enabling easy design modifications by simply changing the extrusion die rather than retooling entire injection molds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If single material composition is used for gasket, then the manufacturing process is simple, but the gasket cannot be optimized for different functional regions

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddesign flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by creating multi-layer TPV structures with different hardness levels in different regions of the gasket. This allows soft regions for sealing contact and harder regions for structural support, optimizing performance for different functional requirements while maintaining relative manufacturing simplicity through co-extrusion processes.

Inventive Principle:

Principle #3Local quality

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 extrusion molded gaskets provide enhanced durability, reduced friction, and cost-effectiveness by enabling design flexibility and ease of modification, while maintaining a watertight seal.

Implementation Method 1

at least one thermoplastic vulcanizate (TPV) comprising at least 15 wt %, by weight of the TPV, of a cross-linkable ethylene-based elastomer

Methodology Applied

Scientific EffectCross-linking: Chemical Bonding

Implementation Method 2

the TPV is extrusion molded into the gasket

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

extrusion molded at least one TPV into a annular form

Methodology Applied

Scientific EffectExtrusion: Extrusion

Implementation Method 4

the gaskets may contain organic and/or oleo-chemicals (e.g., slip agents) to reduce the coefficient of friction (COF) of the gasket surface

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS12516733B2Extrusion molded thermoplastic vulcanizate gaskets and methods of making such gaskets

Publication Date: 2026.01.06 CELANESE INTERNATIONAL CORP

AI summary

An extrusion molded gasket and a method of making such a gasket comprising one or more annular sections configured to engage a door rim of an appliance tub, one or more annular sections configured to engage the appliance tub, and one or more sealing sections disposed therebetween, wherein the gasket comprises at least one thermoplastic vulcanizate comprising at least 15 wt %, by weight of the thermoplastic vulcanizate (TPV), of a cross-linkable ethylene-based elastomer and within a range from 5 to 30 wt %, by weight of the TPV, of at least one thermoplastic, the TPV having a Shore Hardness within a range from 35 A to 100 A (or 50 D), and wherein the TPV is extrusion molded into the gasket.