Polyurethane-Polyisocyanurate Compound with Temperature-Dependent Catalyst
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Solution Overview
Problem
Current polyurethane-polyisocyanurate systems have short open times at room temperature and high brittleness, limiting their application in producing large surface area plastics with long open times and rapid curing, which is essential for automotive and aerospace components requiring high mechanical resistance and impact toughness.
Innovation Solution
A process involving the mixing of polyisocyanate with a mixture containing an alkali metal or alkaline earth metal salt and compounds with urethane groups, epoxide groups, and isocyanate-reactive groups, with specific molar ratios and reaction conditions to achieve a polyurethane-polyisocyanurate compound with extended open time at room temperature and rapid curing at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If epoxy systems or unsaturated polyester systems are used to achieve long open time, then open time is extended, but curing time becomes excessively long
Solution Approach 1:
The patent uses acid-blocked catalysts that change their activity state based on temperature. At room temperature, the catalyst is blocked by acid groups, providing long open time. When heated to elevated temperatures, the acid groups are neutralized and the catalyst becomes active, enabling rapid curing. This parameter change (temperature-dependent catalyst activity) resolves the contradiction between long open time and fast curing time.
2Loss of time
If conventional polyurethane systems are used to achieve rapid curing, then curing time is reduced, but open time becomes too short for large surface area applications
Solution Approach 1:
The patent implements a dynamic catalyst system where catalyst activity is controlled by temperature conditions. The acid-blocked catalyst remains inactive at room temperature (providing long open time) and becomes active when heated (enabling rapid curing). This dynamic control of catalyst activity allows the system to adapt to different processing stages, resolving the contradiction between short open time and fast curing.
3Productivity
If polyisocyanurate components are used to achieve rapid curing, then curing speed increases, but brittleness and impact toughness deteriorate
Solution Approach 1:
The patent creates a composite polyurethane-polyisocyanurate system that combines the advantages of both polymer types. The polyurethane matrix provides flexibility and impact toughness, while the polyisocyanurate segments contribute to rapid curing and high mechanical strength. This composite structure resolves the contradiction between fast curing and good impact toughness by integrating complementary material 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 process results in a polyurethane-polyisocyanurate compound with a long open time at room temperature and rapid curing within minutes at elevated temperatures, providing high mechanical properties and impact toughness, suitable for large surface area plastics in automotive and aerospace applications.
Implementation Method 1
mixing polyisocyanate (a) with a mixture obtainable by introducing an alkali metal or alkaline earth metal salt into a compound R—NH—CO—R′ containing urethane groups
Data Source
AI summary
Polyurethane-polyisocyanurate compounds and processes for preparing polyurethane-polyisocyanurate compounds are disclosed herein. A process includes mixing component (a) polyisocyanate with component (b) a mixture obtainable by introducing an alkali metal or alkaline earth metal salt into a compound R—NH—CO—R containing urethane groups, where R is not hydrogen and is not COR, component (c) compounds containing one or more epoxide groups, component (d) one or more compounds having at least two isocyanate-reactive groups, comprising compounds having NH2 and/or primary OH groups, and component (e) optionally fillers and other additives, to form a reaction mixture, and reacting the reaction mixture to form the polyurethane-polyisocyanurate compound, wherein the molar amount of alkali metal and/or alkaline earth metal ions in the reaction mixture per mole of urethane group in component (b) is 0.0001 to 3.5 and the isocyanate index is greater than 150. Use of polyurethane-polyisocyanate compounds for producing vehicle parts is also disclosed.