Polyurethane System for Low-Temperature Molding
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Solution Overview
Problem
The production of polyurethane sandwich components requires high mold temperatures for short demolding times, leading to increased energy consumption and limited use of heat-sensitive decorative materials, while also posing challenges in achieving adequate flowability and edge sealing.
Innovation Solution
A polyurethane system comprising polyisocyanates, isocyanate-reactive compounds, carboxylic salts of amine catalysts, and reactive chain extenders is used, allowing for a reduced mold temperature and improved lamination behavior without shortening the open time or lengthening demolding times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high mold temperatures (120-140°C) are used to ensure short demolding times and maintain flowability, then demolding time is reduced and productivity is improved, but energy consumption increases and heat-sensitive decorative materials cannot be used for direct lamination
Solution Approach 1:
The invention changes the chemical parameters of the polyurethane system by introducing a carboxylic acid-modified amine catalyst system. The carboxylic acid reacts with the amine catalyst to form a carboxylate salt in situ, which modifies the catalyst's activity and allows the reaction to proceed effectively at lower temperatures (below 120°C). This parameter change in catalyst chemistry enables reduced mold temperature while maintaining acceptable demolding times and flowability.
Solution Approach 2:
The invention creates a composite catalyst system where carboxylic acid and amine catalyst work together synergistically. The carboxylic acid component modifies the amine catalyst to form a composite catalytic system that operates effectively at lower temperatures. This composite approach allows the polyurethane reaction to proceed at reduced temperatures while maintaining the necessary reaction rate and flow properties during molding.
2Productivity
If high mold temperatures (120-140°C) are used to ensure short demolding times, then demolding efficiency is improved, but the selection of decorative materials is limited to heat-resistant materials only
Solution Approach 1:
The invention changes the thermal parameter of the molding process by using a modified catalyst system that enables effective polyurethane formation at lower temperatures. The carboxylic acid-modified amine catalyst allows the reaction to proceed at temperatures below 120°C, which expands the range of compatible decorative materials to include heat-sensitive materials such as certain plastics, vinyls, and organic-coated substrates that would otherwise be damaged by high-temperature molding.
Solution Approach 2:
The composite catalyst system of carboxylic acid and amine creates a milder thermal environment during polyurethane formation. This composite catalytic approach enables the use of diverse decorative materials with different thermal stabilities, including heat-sensitive materials, while still achieving adequate cure and demolding times through the synergistic catalytic action.
3Manufacturing precision
If the open time is extended to allow proper flow and sealing, then edge sealing quality is improved, but the demolding time increases and productivity decreases
Solution Approach 1:
The invention changes the kinetic parameters of the polyurethane reaction by using the carboxylic acid-modified amine catalyst system. This modified catalyst provides a more controlled and sustained catalytic activity that maintains appropriate viscosity and flow characteristics for longer periods, enabling adequate edge sealing and flow into compressed regions. The modified catalyst system extends the effective open time without requiring proportionally longer demolding times, as the reaction progresses more uniformly at the lower processing temperature.
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
This approach reduces energy consumption and enables the use of heat-sensitive materials for lamination, while maintaining the necessary flowability and achieving high-quality edges in polyurethane sandwich components.
Implementation Method 1
at least one carboxylic salt of an amine catalyst, where, based on one equivalent of the amine of the amino catalyst, from 0.5 to 1.5 equivalents of acid groups of a carboxylic acid are comprised
Implementation Method 2
polyisocyanates, (b) at least one isocyanate-reactive compound
Data Source
AI summary
The present invention relates to the use of a polyurethane system, comprising (a) polyisocyanates, (b) at least one isocyanate-reactive compound, (c) at least one carboxylic salt of an amine catalyst, where, based on one equivalent of the amine of the amino catalyst, from 0.5 to 1.5 equivalents of acid groups of a carboxylic acid are comprised, (d) if appropriate, further catalysts, (e) if appropriate, a reactive chain extender having at least two groups reactive toward isocyanates, where at least one group reactive toward isocyanates is a free, primary, NH2 group, and (f) if appropriate, further additives, for the production of polyurethane sandwich components. The present invention further relates to a process for the production of polyurethane sandwich components, and also to the polyurethane sandwich components obtained by the process of the invention.