Polyurethane Foam Steering Wheel Water Resistance
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Solution Overview
Problem
Conventional waterborne polyurethane foams used in automobile steering wheels face issues with durability, including hydrolysis due to humidity, accelerated aging, and increased maintenance costs under severe operating conditions, necessitating improved water resistance and longevity.
Innovation Solution
A polyurethane foam is prepared using a specific blend of polyols, isocyanates, chain extenders, and a crosslinking agent, with water as the foaming agent, to enhance durability and water resistance, comprising a mixture of polyols with varying functional groups and OH values, and isocyanates with different properties, along with glycols and glycerol, to create a more stable and resistant material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional waterborne polyurethane foam is used, then environmental friendliness is improved by using water as foaming agent, but durability and water resistance deteriorate due to hydrolysis and cracking
Solution Approach 1:
The patent uses a composite polyol system comprising multiple types of polyols (polyester polyol, polyether polyol, and poly silicone oxide) with different functional groups and molecular weights to create a polyurethane foam that achieves both environmental friendliness and durability. This composite approach allows the material to maintain water resistance while preventing hydrolysis and cracking under severe conditions.
Solution Approach 2:
The patent optimizes specific parameters including the OH value (50-400 mg KOH/g), nitrogen content (1.0-5.0 wt%), and the ratio of different polyol components to enhance the water resistance and durability of the polyurethane foam. These parameter adjustments prevent hydrolysis while maintaining the environmental benefits of using water as a foaming agent.
2Strength
If in-mold paint is applied to protect polyurethane, then abrasion resistance is improved, but water resistance deteriorates when paint layer is damaged
Solution Approach 1:
The patent extracts the water resistance function from the protective coating (in-mold paint) and integrates it directly into the polyurethane foam base material through optimized polyol composition and crosslinking density. This allows the foam itself to provide water resistance even when the surface coating is damaged or absent.
Solution Approach 2:
The patent adjusts the crosslinking density and chemical composition parameters of the polyurethane foam to enhance its inherent water resistance. By optimizing the polyol structure and crosslinking agents, the foam achieves water resistance without relying on protective coatings that can be damaged.
3Strength
If polyol with high functional groups is used, then crosslinking density is improved, but water resistance deteriorates due to increased hydrolysis susceptibility
Solution Approach 1:
The patent applies local quality by using different types of polyols with different functional group characteristics in specific proportions. Polyester polyol provides crosslinking density while polyether polyol and poly silicone oxide provide water resistance, creating a balanced local composition that achieves both crosslinking and hydrolysis resistance.
Solution Approach 2:
The patent employs a composite polyol system where polyester polyol (providing crosslinking) is combined with polyether polyol and poly silicone oxide (providing water resistance). This composite approach allows simultaneous achievement of high crosslinking density and water resistance by leveraging the complementary properties of different polyol types.
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 resulting polyurethane foam exhibits improved durability, reduced cracking, and enhanced resistance to abrasion and delamination, even under severe conditions such as sweat and prolonged exposure to solar light, while being environmentally friendly by using water as a foaming agent.
Implementation Method 1
Water reacts with isocyanate molecule in the formation of urethane, thereby forming unstable carbamic acid, which is decomposed to produce amine and carbon dioxide
Implementation Method 2
unstable carbamic acid, which is decomposed to produce amine and carbon dioxide
Implementation Method 3
Carbon dioxide gas forms small foams in polyurethane resin, thereby forming a dispersed cell structure in polyurethane
Implementation Method 4
Thus produced amine reacts with isocyanate to form urea group (—NHCONH—)
Data Source
AI summary
The present invention provides a polyurethane foam for an automobile steering wheel. More particularly, the present invention relates to polyurethane foam formed by using a predetermined amount of a polyol having various functional groups and OH values and a predetermined amount of isocyanate having a certain function, along with water as a foaming agent, thereby preventing the environmental problems caused by use of the conventional fluorine-based or pentane-based foaming agent and also improving durability such as water resistance.