Composite Profiles with Filler-Free Polyurethane Foam
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Solution Overview
Problem
Existing processes for producing composite profiles with metal shells and rigid polyurethane foam used in window and door frames face deformation issues during high-temperature surface coating due to gas expansion and thermal expansion differences, and the use of fillers can lead to brittleness, dust formation, and reduced flexibility, especially at low temperatures.
Innovation Solution
A process involving the introduction of polyisocyanate, polyfunctional compounds, formic acid as a blowing agent, and optional flame retardants and catalysts into the hollow space between metal shells and polyamide struts to form a rigid polyurethane foam without inorganic fillers, ensuring complete filling and maintaining mechanical properties and thermal insulation while preventing deformation during high-temperature surface coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mineral fillers are added to counter deformation during surface coating, then deformation is prevented, but brittleness increases and flexibility decreases especially below 0°C
Solution Approach 1:
The invention extracts and removes the harmful mineral fillers from the foam composition while maintaining the deformation-prevention effect through alternative means (optimized blowing agent selection and foam density control), thereby eliminating brittleness and flexibility loss
Solution Approach 2:
The invention changes the chemical composition parameters by using formic acid as blowing agent and adjusting foam density to 30-80 kg/m³, which alters the foam's thermal and mechanical properties to prevent deformation without requiring mineral fillers that cause brittleness
2Manufacturing precision
If mineral fillers are added to counter deformation during surface coating, then deformation is prevented, but dust formation increases during cutting or sawing
Solution Approach 1:
The invention extracts and removes mineral fillers from the foam composition, eliminating the source of dust formation during cutting and sawing operations while maintaining deformation prevention through alternative foam formulation
3Manufacturing precision
If hollow space is only partly filled with polyurethane foam to avoid deformation, then deformation is reduced, but thermal insulation properties deteriorate
Solution Approach 1:
The invention changes the foam density parameter to an optimized range of 30-80 kg/m³ and uses formic acid as blowing agent, enabling complete filling of the hollow space while maintaining both deformation prevention and superior thermal insulation properties
Solution Approach 2:
The invention creates a composite structure with metal shells, thermoplastic struts, and optimized polyurethane foam, where the specific foam composition (with formic acid blowing agent) provides both structural stability during coating and enhanced thermal insulation
4Reliability
If complete filling with foam is performed to improve insulation, then thermal insulation improves, but deformation occurs during high-temperature surface coating
Solution Approach 1:
The invention changes the foam composition parameters including using formic acid as blowing agent and optimizing density to 30-80 kg/m³, which allows the foam to maintain dimensional stability during high-temperature coating while providing excellent thermal insulation
Solution Approach 2:
The invention converts the potential harm of gas expansion during heating into a benefit by selecting formic acid as blowing agent, which produces controlled gas evolution that maintains foam structure integrity during the surface coating process
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 produces composite profiles that remain deformation-free during high-temperature surface coating and maintain good mechanical properties at low temperatures, eliminating dust formation and brittleness, with enhanced thermal insulation and processing ease.
Implementation Method 1
one or more blowing agents comprising at least formic acid
Implementation Method 2
the rigid polyurethane foam being formed by reaction of the following components: A) at least one polyisocyanate, B) at least one polyfunctional compound which is reactive toward isocyanates, C) one or more blowing agents comprising at least formic acid
Implementation Method 3
a core comprising rigid polyurethane foam... used, for example, for window frames and doorframes... good mechanical properties even at temperatures below 0° C. and can be cut without dust formation
Implementation Method 4
rigid polyurethane foam being formed by reaction of the following components: A) at least one polyisocyanate, B) at least one polyfunctional compound which is reactive toward isocyanates
Data Source
AI summary
The present invention relates to a process for producing composite profiles comprising at least two metal shells which are joined by struts comprising a thermoplastic material and a core comprising rigid polyurethane foam, which comprises introduction of the starting components of the rigid polyurethane foam into a hollow space formed by the metal shells, with the rigid polyurethane foam being formed, and subsequent application of a surface coating to the outer surface of the composite profile by means of a powder coating or baking enamel, where the rigid polyurethane foam is obtained by reaction of the following components:A) at least one polyisocyanate,B) at least one polyfunctional compound which is reactive toward isocyanates,C) one or more blowing agents comprising at least formic acid,D) optionally one or more flame retardants,E) optionally one or more catalysts andF) optionally further auxiliaries or additives,wherein the starting components of the rigid polyurethane foam do not comprise any inorganic fillers.