Multi-phase Polyurethane Composition Reducing Bubble Formation
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Solution Overview
Problem
Two-component polyurethane compositions used in fiber composite materials often experience bubble formation during crosslinking due to water reaction with isocyanate groups, leading to defects and inadequate fracture toughness, and current release agents provide insufficient mold release, making material removal difficult.
Innovation Solution
A two-component polyurethane composition comprising a polyol and polyisocyanate with an emulsifier that is not homogeneously miscible with the polyol, having a specific HLB value and viscosity, and containing converted carbodiimide and/or uretonimine groups, which reduces bubble formation and enhances mechanical properties and mold release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional release agents are used on the mold surface, then mold release is achieved, but additional work steps are required and release effect is often inadequate
Solution Approach 1:
The polyol component is formulated to inherently provide release properties through its chemical composition and phase separation behavior, eliminating the need for separate release agent applications. The composition serves both as matrix resin and release agent, reducing process complexity while maintaining effective mold release.
Solution Approach 2:
The polyol component performs multiple functions simultaneously: it acts as the matrix resin binder, provides phase separation for gas absorption, and serves as an internal release agent. This multi-functionality consolidates multiple process steps into one, reducing operational complexity while maintaining release effectiveness.
2Strength
If highly cross-linked 2K PU compositions are used to increase strength, then fracture toughness becomes inadequate and operational stability decreases
Solution Approach 1:
The composition creates local phase separation with distinct regions of different crosslinking densities. The first phase provides a softer matrix with better toughness and operational stability, while the second phase provides harder regions for strength. This local differentiation allows both fracture toughness and operational stability to be maintained simultaneously.
Solution Approach 2:
The invention creates a multi-phase composite structure within the polyurethane matrix, where regions of different chemical composition and crosslinking density coexist. This composite structure at the micro-scale provides both the toughness needed for operational stability and the strength required for mechanical performance.
3Object-affected harmful factors
If low-viscosity compositions are used to reduce bubble formation during flow, then bubble formation is reduced, but the composition may have inadequate mechanical properties
Solution Approach 1:
The invention changes the physical parameters of the polyol component by introducing phase separation and adjusting viscosity characteristics. The composition maintains low viscosity during application to prevent bubble formation, then undergoes transformation during curing to develop the required mechanical strength through crosslinking and phase separation.
Solution Approach 2:
The composition is designed to absorb gases and bubbles during the flow and curing process through its phase separation characteristics, cushioning against the harmful effects of bubble formation before they can create defects in the final product.
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 composition significantly reduces bubble formation, improves mechanical properties, and facilitates easier removal of the molded part from the mold by increasing fracture toughness and absorption capacity for dissolved gases, resulting in high-strength fiber composite materials.
Implementation Method 1
The composition exhibits phase separation after curing
Implementation Method 2
increasing fracture toughness and absorption capacity for dissolved gases
Implementation Method 3
water reaction with isocyanate groups, leading to defects
Implementation Method 4
reacts with the isocyanate groups contained therein to form carbon dioxide
Data Source
AI summary
The invention relates to a two-component polyurethane composition, comprising at least one polyol, at least one polyisocyanate, and at least one emulsifier, which emulsifier is not homogeneously miscible with the at least one polyol. The invention further relates to the use of said polyurethane composition as a binder for producing fiber composite materials, to a method for producing said fiber composite materials, to the fiber composite materials themselves, and to use of the fiber composite materials.