Polyurethane Bound Stopper with Polyrotaxane for Fatigue Durability
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Solution Overview
Problem
The control of reaction conditions for producing bound stoppers with high mechanical strength and durability is challenging due to the difficulty in satisfying specific density and foam cell diameter relationships during primary and secondary vulcanization processes.
Innovation Solution
A bound stopper made of polyurethane foam, comprising a urethane prepolymer with an isocyanate group obtained by mixing a polyol component and polyrotaxane containing a cyclic molecule with an active hydrogen group, which reacts with an isocyanate to form a urethane bond, providing improved mechanical strength and durability through a pulley effect and air spring effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If primary and secondary vulcanization are performed to achieve specific density and foam cell diameter relationships, then mechanical strength and durability are improved, but the control of reaction conditions becomes difficult
Solution Approach 1:
The invention changes the chemical composition parameters of the polyol component by introducing polyrotaxane with cyclic molecules containing active hydrogen groups. This parameter change modifies the reaction characteristics during vulcanization, enabling the formation of a urethane prepolymer with improved properties that simplifies process control while achieving the required density and foam cell diameter relationships for high mechanical strength and durability
Solution Approach 2:
The invention uses a composite polyol system combining conventional polyol with polyrotaxane containing cyclic molecules. This composite material approach creates a urethane prepolymer with enhanced structural properties that simultaneously improves mechanical strength and durability while making the reaction control more manageable during primary and secondary vulcanization processes
2Reliability
If polyrotaxane is added to improve mechanical strength and durability, then fatigue resistance is enhanced, but the production process complexity increases
Solution Approach 1:
The invention performs preliminary action by pre-forming the urethane prepolymer containing polyrotaxane and isocyanate groups before the main foaming process. This preliminary preparation ensures uniform distribution of polyrotaxane throughout the polyurethane foam composition, which improves durability against fatigue breaking while avoiding the need for complex dispersion processes during production
Solution Approach 2:
The urethane prepolymer acts as an intermediary that facilitates the integration of polyrotaxane into the polyurethane foam matrix. By using this intermediate compound with pre-formed isocyanate groups, the invention simplifies the production process while ensuring thorough mixing and uniform dispersion of polyrotaxane, thereby achieving enhanced fatigue resistance without excessive process complexity
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 enhances mechanical strength, reduces dynamic energy absorption, and improves durability against fatigue and repeated loading, while simplifying the production process by eliminating the need for dispersion media and ensuring uniform dispersion of polyrotaxane.
Implementation Method 1
mixing a polyol component and a polyrotaxane containing a cyclic molecule having an active hydrogen group as a constituent in a molten state
Implementation Method 2
blending the mixture with an isocyanate... the cyclic molecules 21 of the polyrotaxane 20 react with the isocyanate to form a urethane bond
Implementation Method 3
injecting a polyurethane foam composition containing the urethane prepolymer having an isocyanate group and a blowing agent into a mold and foaming the same
Data Source
AI summary
The present invention is to provide a bound stopper, which has high mechanical strength, is excellent in durability against fatigue breaking, settling or the like when a heavy load is repeatedly received, and is easy to be produced, in which the bound stopper comprises a polyurethane foam obtained from a polyurethane foam composition containing an isocyanate component and a blowing agent, and the isocyanate component contains a urethane prepolymer having an isocyanate group, the urethane prepolymer being obtained from a polyol component, a polyrotaxane containing a cyclic molecule having an active hydrogen group as a constituent, and an isocyanate.