Low-Viscosity Polyurethane Composite Surface Structure Transfer

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Solution Overview

Problem

Existing methods for producing fiber composite components, such as those used in automotive and aviation, face limitations in design options due to high pressure requirements for epoxy resin-based processes, which restrict surface structure complexity and lead to stress and distortion in components.

Innovation Solution

A method utilizing a low-viscosity polyurethane matrix material and a tool with a finely structured surface, allowing for the production of fiber composite components with intricate surface features under low pressure, enabling stress-free and distortion-free geometry with high surface accuracy, and incorporating in-mold coating for additional finish.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If epoxy resin is used as matrix material with high pressure introduction, then fiber composite components can be produced with good structural integrity, but surface structure design options are limited and surface quality deteriorates with rests and inserts

Engineering Contradiction:
Improvestructural integrityVSAvoidsurface quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent changes the key parameter of matrix material viscosity by selecting low-viscosity materials (polyester resin, vinyl ester resin, or epoxy resin with viscosity ≤1000 cP at 25°C). This parameter change allows the resin to be introduced at low pressure while still achieving complete impregnation of the fiber reinforcement, thereby enabling complex surface structures to be reproduced accurately without the high pressure that causes surface defects.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a vacuum as an intermediary force to assist the low-viscosity resin in penetrating the fiber reinforcement. By applying vacuum (≤0.95 bar) during resin introduction, the process achieves complete impregnation without requiring high pressure, thus preserving surface structure quality while ensuring structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If high pressure is used to introduce resin into the tool, then complete impregnation of fiber material is achieved, but component geometry becomes distorted and stress is introduced

Engineering Contradiction:
Improvecomplete impregnationVSAvoidgeometry accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the viscosity parameter of the matrix material to ≤1000 cP at 25°C for epoxy resin (or uses polyester/vinyl ester resin), which enables complete fiber impregnation at low pressure. This parameter change eliminates the need for high pressure that causes geometric distortion and residual stress, while still achieving stable and complete resin distribution throughout the fiber reinforcement.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses vacuum as an intermediary mechanism to achieve complete impregnation without high pressure. The vacuum assists the low-viscosity resin in penetrating the fiber matrix uniformly, ensuring complete impregnation and stable composition while maintaining geometric accuracy and avoiding stress introduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If complex surface structures are attempted with high pressure processes, then surface detail can be transferred, but press systems cannot be used on inclined or perpendicular surfaces and surface quality deteriorates

Engineering Contradiction:
Improvesurface structure transferVSAvoidprocess versatility
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the viscosity parameter of the matrix material to low values (≤1000 cP for epoxy, or using polyester/vinyl ester), which enables the resin to flow and penetrate fiber reinforcement effectively under low pressure. This allows complex surface structures to be transferred accurately to components with inclined or perpendicular surfaces without requiring high-pressure press systems, thereby improving process versatility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces vacuum as an intermediary force to assist resin flow and impregnation. This vacuum assistance enables complete fiber saturation and accurate surface structure transfer on complex geometries (inclined or perpendicular surfaces) without requiring high-pressure equipment, thus expanding process versatility while maintaining manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for the creation of fiber composite components with visually appealing, high-resolution surface structures that reduce processing costs and enable advanced surface properties like low flow resistance and self-cleaning capabilities, while maintaining component integrity and reducing fuel consumption.

Implementation Method 1

a low-viscosity matrix material, preferably a duroplastic, particularly preferably polyurethane

Methodology Applied
Scientific EffectViscosity:

Implementation Method 2

a low-viscosity matrix material, preferably a duroplastic, particularly preferably polyurethane

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP2774738B1Method for producing a fibre composite component with surface structure and component obtained thereby
Publication Date: 2017.09.13 FRIMO GRP GMBH
  • EP2774738B1 patent drawingFigure 1

AI summary

The method involves placing a fiber perform in a tool, and introducing a low-viscosity matrix material, particularly thermosetting plastic, such as polyurethane, in the tool for forming a matrix of a fiber composite component. The fiber composite component is removed from the tool. A coating, particularly a painting, is introduced on one of the tool halves (1,2) of the tool. One of the tool halves made from aluminum or plastic has a finely structured upper surface (1a) in a partial manner. The fiber preform has glass fiber, carbon fiber, aramid fiber, natural fiber and basalt fiber.