Fibered Polyurethane Foam Block Constrained Expansion
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Solution Overview
Problem
Current methods for producing fibered polyurethane and polyisocyanurate foams struggle to achieve optimal mechanical properties in thickness while maintaining thermal insulation performance and are economically inefficient due to material loss and heterogeneity issues.
Innovation Solution
A process involving controlled impregnation of fibers with a mixture of chemical components and constrained expansion in a double-belt laminator, optimizing the expansion volume to achieve a foam block with cells aligned parallel to the thickness, ensuring homogeneous fiber distribution and reduced material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fibers are added to PUR/PIR foam production, then mechanical strength is improved, but homogeneous fiber distribution becomes difficult to achieve
Solution Approach 1:
Fibers are pre-coated with polyol solution before being placed in the foam mold, ensuring uniform fiber distribution and preventing aggregation. This preliminary preparation step guarantees homogeneous fiber dispersion throughout the foam structure, resolving the contradiction between achieving high mechanical strength through fiber reinforcement and maintaining manufacturing precision regarding fiber distribution uniformity
2Strength
If foam expansion is strongly constrained by laminator walls, then mechanical properties in length direction are improved, but fiber impregnation homogeneity deteriorates
Solution Approach 1:
The foam composition is pre-coated with polyol solution and fibers are pre-positioned and pre-coated before entering the laminator. This preliminary impregnation ensures that fibers are uniformly distributed and saturated with reactive components before the expansion and constraining process begins, allowing the subsequent mechanical constraint to improve strength without compromising fiber impregnation homogeneity
Solution Approach 2:
The polyol solution is applied at specific concentrations and viscosities controlled by parameters such as temperature, humidity, and coating speed. By optimizing these parameters, the solution ensures adequate fiber impregnation even under strong expansion constraints, resolving the contradiction between mechanical property improvement and impregnation homogeneity
3Manufacturing precision
If free expansion is used without constraints, then fiber distribution is easier to control, but material loss increases due to heterogeneous foam structure
Solution Approach 1:
The foam expansion is controlled by adjusting parameters such as temperature, pressure, and composition ratios to achieve optimal cell structure formation. By precisely controlling these parameters during the expansion process, homogeneous foam structure is achieved while minimizing material loss, resolving the contradiction between manufacturing precision and substance loss
4Productivity
If conventional foam production methods are used, then production speed is maintained, but thermal insulation performance deteriorates due to poor cell orientation
Solution Approach 1:
The foam composition is pre-prepared with controlled viscosity and cell-nucleating agents that promote uniform cell formation and orientation during expansion. This preliminary preparation ensures that when the foam expands under controlled conditions, cells align in the desired direction, achieving excellent thermal insulation performance while maintaining high production speed through efficient process integration
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 fibered foam block with excellent mechanical properties and minimal material loss, maintaining thermal insulation performance with thermal conductivity below 30 mW/m.K, suitable for cryogenic applications.
Implementation Method 1
at least one blowing agent consisting of a physical and/or chemical expanding agent
Implementation Method 2
The formation of polyurethane foams is well understood by those skilled in the art. Its formation involves a multi-component reaction between a polyol... a polyisocyanate... and a blowing agent. This condensation reaction is notably catalyzed by basic and/or nucleophilic compounds
Implementation Method 3
This condensation reaction is notably catalyzed by basic and/or nucleophilic compounds such as tertiary amines or metal-carboxylate coordination complexes like tin or bismuth salts
Implementation Method 4
a step of forming and expanding the fiber-reinforced polyurethane/polyisocyanurate foam, said expansion of the fiber-reinforced polyurethane/polyisocyanurate foam being physically constrained by the walls of a twin-belt laminator forming a tunnel
Implementation Method 5
The process results in a fibered foam block with excellent mechanical properties and minimal material loss, maintaining thermal insulation performance with thermal conductivity below 30 mW/m.K, suitable for cryogenic applications
Data Source
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AI summary
The present invention relates to a preparation of a block of fiberized polyurethane/polyisocyanurate foam in which the expansion of the foam is constrained by the walls of a double-belt laminator forming a tunnel, the positioning of the walls of the tunnel of the double-belt laminator being defined so that the expansion constraint on the fiberized polyurethane/polyisocyanurate foam leads to a volume of fiberized polyurethane/polyisocyanurate foam, exiting the double-belt laminator, representing between 92% and 99% of the expansion volume of this same fiberized polyurethane/polyisocyanurate foam in the case of free expansion, without the constraint of the walls of such a double-belt laminator.