Cellular Polyurethane Tire Formulation for Deflation Resistance
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Solution Overview
Problem
Existing polyurethane elastomers used in tires lack dynamic performance, hydrolysis resistance, and wear resistance, making them unsuitable for high-temperature and moisture exposure, and prone to deflation due to punctures or rim separation.
Innovation Solution
A cellular polyurethane elastomeric material with specific Shore A hardness, compression set, and ball rebound properties is developed using a reaction system comprising a polyisocyanate composition, polyether polyols, chain extenders, and blowing agents, which are processed through rotating moulding to create tires with improved hydrolysis and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane foam is used to fill tires, then the risk of deflation is eliminated, but the compression set value becomes too high (10-20%)
Solution Approach 1:
The patent modifies the chemical composition parameters of the polyurethane foam by selecting specific polyols (polyester polyols with hydroxyl number 30-70 mg KOH/g and molecular weight 1000-3000 g/mol) and controlling the isocyanate index (100-120), thereby optimizing the cellular structure to achieve compression set below 10% while maintaining deflation resistance
Solution Approach 2:
The patent creates a composite polyurethane foam system combining specific polyester polyols, polyisocyanates (MDI or TDI), chain extenders (ethylene glycol, butanediol), and blowing agents (water, ammonia, CO2) to achieve a balanced cellular structure that simultaneously provides low compression set and high reliability
2Reliability
If polyurethane elastomer is made softer to provide good traction and shock absorption, then dynamic performance improves, but hydrolysis resistance deteriorates
Solution Approach 1:
The patent optimizes the polyol selection parameters by using polyester polyols with specific hydroxyl numbers (30-70 mg KOH/g) and molecular weights (1000-3000 g/mol), which balance the softness required for dynamic performance with hydrolysis resistance by controlling the polymer chain structure and crystallinity
Solution Approach 2:
The patent introduces different functional components at specific ratios: polyester polyols for softness and flexibility, aromatic polyisocyanates for hydrolysis resistance, and controlled amounts of chain extenders to create a multi-phase structure where hard segments provide chemical stability while soft segments provide dynamic performance
3Reliability
If polyurethane elastomer is made softer to absorb shock, then traction and comfort improve, but heat buildup during use increases excessively
Solution Approach 1:
The patent controls the Shore A hardness within 40-70 degrees through precise formulation of polyol-to-isocyanate ratios (isocyanate index 100-120) and selection of polyester polyols with specific molecular weights, creating an optimized cellular structure that dissipates energy efficiently without excessive heat generation
Solution Approach 2:
The patent utilizes a controlled cellular foam structure with specific density (0.03-0.08 g/cm³) where the cell walls and pores provide shock absorption through cellular deformation rather than material softening, thereby reducing heat buildup while maintaining traction and comfort properties
4Ease of manufacture
If existing polyurethane formulations are used, then manufacturing is simple, but wear resistance and hydrolysis resistance are insufficient
Solution Approach 1:
The patent employs a composite formulation system combining polyester polyols, aromatic polyisocyanates, chain extenders, and blowing agents in specific proportions that can be processed using conventional two-component injection molding equipment, maintaining manufacturing simplicity while achieving superior wear and hydrolysis resistance through the synergistic interaction of components
Solution Approach 2:
The patent optimizes the isocyanate index to 100-120 and controls the molecular weight of polyester polyols within 1000-3000 g/mol, creating a formulation that cures at standard temperatures (20-50°C) over 10-60 minutes using conventional equipment, thereby maintaining ease of manufacture while significantly improving durability properties
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 tires exhibit enhanced dynamic performance, hydrolysis resistance, and wear resistance, comparable to pneumatic tires, while eliminating the risk of deflation due to punctures or rim separation, and demonstrate improved rolling resistance and power performance.
Implementation Method 1
a cellular polyurethane elastomeric material... using a reaction system comprising a polyisocyanate composition, polyether polyols, chain extenders
Implementation Method 2
blowing agents, which are processed through rotating moulding to create tires
Data Source
AI summary
Polyurethane elastomeric compositions for making tires, methods for making said tires and tires made of said polyurethane elastomers. Said tires are in particular suitable for use as tires for low speed vehicles such as bicycle tires.