Polyurethane Repair Kit Composition for Fast On-Site Curing
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Solution Overview
Problem
Existing repair kits for industrial equipment are hazardous, require skilled operators, have long curing times, and do not provide adequate hydrolytic and weather resistance, making them inconvenient and unsafe for on-site repairs.
Innovation Solution
A multi-part kit system comprising MDI prepolymer, fumed silica, and hydroquinone di-(2-hydroxyethyl)ether, with optional catalyst and plasticizer, that can be mixed to form a fast-curing, thixotropic repair material suitable for on-site use, reducing downtime and environmental hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional polyurethane repair materials are used, then the repair can be performed on-site, but the materials are hazardous and require special handling
Solution Approach 1:
The patent changes the chemical parameters of the repair material by using MDI prepolymer with controlled isocyanate content (2-10% by weight) and specific molecular weight (3,500-10,500), along with controlled moisture content (0.5-5% water), to reduce hazardousness while maintaining on-site repair capability. This parameter optimization makes the material safer for field use.
2Productivity
If conventional repair materials are used, then the repair can be performed quickly, but the curing time is still 24 hours or more
Solution Approach 1:
The patent applies preliminary action by pre-forming the MDI prepolymer with controlled characteristics before application. The prepolymer is prepared in advance with specific molecular weight and isocyanate content, allowing it to react more rapidly with atmospheric moisture upon application, thus reducing curing time from 24 hours to 3 hours or less.
3Loss of time
If the repair material cures fast at room temperature, then equipment can return to service quickly, but the material may not have sufficient working time for application
Solution Approach 1:
The patent applies partial action by controlling the isocyanate content at a moderate level (2-10% by weight) rather than using high isocyanate content that would cause extremely rapid curing. This partial optimization provides sufficient working time for application while still achieving fast curing (3 hours or less) once applied, balancing both requirements.
4Reliability
If conventional repair materials are used, then the repair can be performed, but the material lacks hydrolytic stability in high temperature environments
Solution Approach 1:
The patent uses composite material strategy by combining MDI prepolymer with specific plasticizers and maintaining controlled moisture content (0.5-5% water). This composite formulation creates a material that exhibits improved hydrolytic stability and weather resistance (UV and color stability) while maintaining elastomeric properties, suitable for high temperature environments up to 85°C.
5Ease of operation
If the repair material is made trowelable for immediate application, then it can be applied easily to longitudinal damages, but it may flow or change shape before curing
Solution Approach 1:
The patent changes the rheological parameters by incorporating plasticizers and controlling the molecular weight of the prepolymer (3,500-10,500). These parameter adjustments create a thixotropic material that is trowelable and can be applied immediately to longitudinal damages like conveyor belt grooves without flowing or changing shape, while maintaining dimensional stability.
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 kit allows for safe, easy application with reduced environmental health risks, achieving rapid cure times and improved hydrolytic stability, enabling equipment to return to service within 3 hours and providing weather-resistant repairs.
Implementation Method 1
an isocyanate-terminated polytetramethylene ether glycol prepolymer of about 3,500-10,500 molecular weight that cures to an elastomer upon exposure to atmospheric moisture
Implementation Method 2
allows the device being returned to service after a minimum of 3 hours, which has improved hydrolytic stability in environments in the range of 50 to 85° C. and which is weather resistant
Data Source
AI summary
A multi-part kit system may be used to repair damaged products used in industrial applications, comprising a part A which includes (A1) MDI prepolymer, (A2) fumed silica, and (A3) plasticizer; a part B which includes (B1) hydroquinone di-(2-hydroxyethyl)ether and (B2) plasticizer; and a part C which includes (C1) polyol, (C2) optionally, catalyst, and (C3) optionally, plasticizer.