Abrasion-Resistant Polyurethane Steering Wheel Coating

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Solution Overview

Problem

Existing polyurethane coatings for steering wheels lack simultaneous abrasion resistance and soft touch, often delaminate, and have inadequate mechanical stability, adhesion, elasticity, and UV resistance, particularly in automotive applications.

Innovation Solution

A polyurethane foam coating with a hardness of 50 to 90 Shore A is achieved by mixing polyisocyanate with specific functionality, polymeric compounds, trimerization catalysts, and optional chain extenders and additives, applied to create a compact polyurethane with high abrasion resistance and a textured surface, eliminating the need for a separate coating step.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polyurethane coatings are applied to basic polyurethane articles, then the articles gain surface enhancement and resistance to mechanical load, UV radiation, hydrolysis, and solvents, but the coating process becomes highly complicated and requires special coating booths with filters

Engineering Contradiction:
Improveresistance to mechanical load, UV radiation, hydrolysis, and solventsVSAvoidcoating process complexity and special equipment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the basic polyurethane article and the protective coating into a single integral structure. The coating material is introduced into the mold before the polyurethane reaction mixture, and after curing, the ready-coated polyurethane molding is removed as one piece, eliminating the need for separate coating application equipment and post-coating processes

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coating material is introduced into the mold in advance before the polyurethane reaction mixture is injected. This preliminary placement of the coating material allows it to be integrated into the final product without requiring complex application equipment during the manufacturing process

Inventive Principle:
Principle #10Preliminary action

2Reliability

If coating material is sprayed onto basic polyurethane articles, then surface protection is achieved, but paint spray is produced that must not enter the environment, requiring special coating booths

Engineering Contradiction:
Improvesurface protectionVSAvoidpaint spray emissions
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful spray application step from the process entirely. Instead of spraying coating material onto the article, the coating material is placed in the mold and integrated with the polyurethane foam during the foaming process, eliminating paint spray emissions completely

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts what would normally be a harmful emission (paint spray) into a beneficial integrated structure. The coating material becomes part of the foam structure itself, providing protection without generating harmful emissions during application

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If basic polyurethane articles are immersed into coating material, then coating is achieved, but uniform coating film is obtained only when the article is small and simple-shaped and removed at precisely controlled rate

Engineering Contradiction:
Improvecoating film formationVSAvoidapplicability to different article sizes and shapes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of immersing the article into coating material and carefully controlling removal, the patent inverts the process: the coating material is placed in the mold first, then the polyurethane reaction mixture is injected around it. This allows articles of any size or shape to be coated uniformly without precise removal control

Inventive Principle:
Principle #13The other way round (Inversion)

4Reliability

If polyurethane coatings are applied to basic polyurethane articles, then surface enhancement is achieved, but the mechanical stability, adhesion, and elasticity of the coating materials are inadequate

Engineering Contradiction:
Improvesurface enhancementVSAvoidmechanical stability, adhesion, and elasticity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent creates a composite structure where the coating material and polyurethane foam are integrated into a single unit. The coating material is mixed with the polyurethane reaction mixture and foamed together, creating an inseparable bond between the coating and the foam that provides superior mechanical stability, adhesion, and elasticity compared to separate coating layers

Inventive Principle:
Principle #40Composite materials

5Reliability

If polyurethane coatings are applied to basic polyurethane articles, then coating is achieved, but the resistance towards solvents and UV stability are inadequate

Engineering Contradiction:
Improvecoating formationVSAvoidsolvent resistance and UV stability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The integrated composite structure of coating material and polyurethane foam creates a unified system with enhanced resistance to solvents and UV stability. The chemical bonding between the coating and foam components provides superior protection against environmental degradation compared to separate coating layers

Inventive Principle:
Principle #40Composite materials

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 provides a steering wheel with enhanced abrasion resistance, ease of processing, low combustibility, and a pleasant touch, while reducing emissions and odor nuisance, thereby addressing the limitations of current coatings.

Implementation Method 1

mixing (a) polyisocyanate having an average functionality of 2 to less than 2.5, (b) polymeric compounds having isocyanate-reactive groups, (c) catalysts, comprising trimerization catalyst, optionally (d) chain extenders, and (e) auxiliaries and/or additives to give a reaction mixture, applying the reaction mixture to an article, and curing the reaction mixture to give the polyurethane coating

Methodology Applied
Scientific EffectPolymerization: Chemical Bonding

Data Source

PatentEP2602271B1Steering wheel from abrasion-resistant polyurethane coating
Publication Date: 2015.07.29 BASF SE

AI summary

The present invention relates to a polyurethane coating having a hardness of 50 to 90 Shore A, obtainable by mixing (a) polyisocyanate having an average functionality of 2 to less than 2.5, (b) polymeric compounds having isocyanate-reactive groups, (c) catalysts, comprising trimerization catalyst, optionally (d) chain extenders, and (e) auxiliaries and/or additives to give a reaction mixture, applying the reaction mixture to an article, and curing the reaction mixture to give the polyurethane coating, the polyisocyanate component (a) and the components (b) to (e) being reacted in amounts such that the isocyanate index is 103 to 200. Further provided with the present invention are a process for producing an abrasion-resistant polyurethane coating, and a steering wheel comprising an abrasion-resistant polyurethane coating.