Sliding Material Silicone Dispersion for Weatherstrip Durability

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Solution Overview

Problem

Conventional sliding materials containing silicone compounds for weather strips face issues such as molding failures, uneven distribution leading to dappled patterns, and reduced durability due to bleeding and squeaking noise, especially when the silicone content is high.

Innovation Solution

A sliding material composed of an olefin-based polymer and a silicone compound, where the olefin-based polymer forms crosslinked domains to disperse the silicone compound uniformly, preventing uneven distribution and ensuring a residual fraction of hot xylene reflux between 33 to 75% and a silicone content of 5 to 20% by weight, optimizing viscosity and domain size for improved durability and reduced noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If silicone compound is added to elastomer-based sliding material to improve lubrication, then sliding resistance decreases, but molding failure occurs due to silicone adhesion to die and uneven distribution

Engineering Contradiction:
Improvesliding resistanceVSAvoidmolding quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces an olefin-based polymer as an intermediary substance between the silicone compound and the die. This polymer has low affinity with silicone, preventing silicone adhesion to the die surface during extrusion molding, thereby eliminating molding failures while maintaining the lubrication benefits of silicone

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the content ratio of silicone compound to olefin-based polymer, specifying that silicone content should be 5-20% by weight. This parameter control ensures sufficient lubrication while preventing excessive silicone that would cause adhesion and uneven distribution problems

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If high content of silicone compound is used to enhance lubrication, then sliding resistance decreases, but bleeding occurs on the surface over time

Engineering Contradiction:
Improvesliding resistanceVSAvoidsurface appearance stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent creates a composite material system combining olefin-based polymer and silicone compound in specific proportions. The olefin polymer matrix provides structural stability and prevents silicone bleeding, while the silicone dispersed phase provides lubrication, achieving both low sliding resistance and surface stability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent ensures uniform local distribution of silicone compound throughout the material matrix through proper mixing and composition control. This prevents local concentration of silicone that would lead to bleeding, while maintaining sufficient silicone presence for lubrication across the entire surface

Inventive Principle:
Principle #3Local quality

3Ease of operation

If silicone compound is added to improve slidability, then initial sliding resistance decreases, but durability deteriorates due to prompt removal during repeated sliding

Engineering Contradiction:
ImproveslidabilityVSAvoidslide durability
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent achieves homogeneous distribution of silicone compound within the olefin polymer matrix through controlled mixing and appropriate composition ratios. This uniform distribution ensures consistent lubrication performance throughout the material, preventing rapid depletion of silicone during repeated sliding and thereby improving slide durability

Inventive Principle:
Principle #33Homogeneity

4Object-affected harmful factors

If silicone compound content is increased to maintain lubrication, then water removal capability improves, but molding failure and appearance problems increase

Engineering Contradiction:
Improvewater removal capabilityVSAvoidmolding quality and appearance
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent optimizes the silicone content parameter to 5-20% by weight, which is sufficient to provide water removal capability and lubrication while remaining below the threshold that causes adhesion, uneven distribution, and appearance problems during molding

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents molding failures, reduces silicone bleeding, and significantly decreases squeaking noise while maintaining high lubrication and water removal capabilities, ensuring long-term low sliding resistance and improved durability.

Implementation Method 1

a part of the olefin-based polymer forms a crosslinked material in the sliding material, the crosslinked material forms domains to disperse in the sliding material so as to prevent uneven distribution of the silicone compound in the extrusion direction

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentEP2042550B1Sliding material, sliding member, and weatherstrip
Publication Date: 2012.09.05 SHIN ETSU POLYMER CO LTD
  • EP2042550B1 patent drawingFigure 1
  • EP2042550B1 patent drawingFigure 2(a)~2(b)
  • EP2042550B1 patent drawingFigure 3(a)~3(b)

AI summary

The sliding material is obtainable by extrusion of a raw material containing an olefin-based polymer and a silicone compound as the essential components. A part of the olefin-based polymer forms a crosslinked material in the sliding material. The crosslinked material forms domains to disperse in the sliding material so as to prevent uneven distribution of the silicone compound in the extrusion direction. The residual fraction of hot xylene reflux of the sliding material is in a range from 33 to 75% by weight based on the total weight of the sliding material, and the content of the silicone compound based on the total weight of the sliding material is in a range from 5 to 20% by weight.