Multilayer composite

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Solution Overview

Problem

Existing multilayer composite bodies for furniture and sanitary applications are complex and expensive to produce, with limited versatility in achieving high-gloss or matte finishes and poor color stability over time, especially when subjected to mechanical stress and temperature variations.

Innovation Solution

A multilayer composite body comprising a first composite panel with a (meth)acrylate copolymer upper layer, a pigment-containing intermediate layer, and a styrene polymer lower layer, connected via a polyurethane reactive hot-melt adhesive, ensuring a linear expansion coefficient match and a thickness ratio that prevents warping, allowing for a cost-effective, versatile, and durable product with high glass appearance and color constancy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a complex multilayer structure with multiple material combinations is used to achieve high-quality surfaces, then surface hardness and scratch resistance are improved, but manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improvesurface hardnessVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines multiple functional layers (transparent top layer, intermediate layer with print receptivity, and base layer) into a single integrated multilayer composite structure. This merging approach maintains the scratch resistance and surface hardness benefits while simplifying manufacturing by creating a unified material system rather than assembling separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite materials with specific property combinations - the transparent top layer provides hardness and scratch resistance, the intermediate layer provides print receptivity and adhesion, and the base layer provides structural support. This composite approach achieves multiple performance requirements simultaneously while managing manufacturing complexity through material selection.

Inventive Principle:
Principle #40Composite materials

2Strength

If conventional multilayer composite materials are used, then surface gloss and scratch resistance are achieved, but the ability to create high-gloss or matte surfaces is limited

Engineering Contradiction:
Improvescratch resistanceVSAvoidsurface finish versatility
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by creating an intermediate layer with specific properties (print receptivity) that is localized between the transparent top layer and the base layer. This intermediate layer can be selectively designed to achieve different surface finishes (high-gloss or matte) while the transparent top layer maintains scratch resistance, allowing versatility in surface appearance without compromising durability.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a plastic sheet with colored lacquer is glued to a substrate, then furniture panel production is enabled, but the lacquer layer is damaged or destroyed during bonding

Engineering Contradiction:
Improvefurniture panel productionVSAvoidlacquer layer integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-equipping the intermediate layer with print receptivity and adhesion properties before the bonding process. This intermediate layer is prepared in advance to receive prints and to provide controlled adhesion to the substrate, preventing damage to the lacquer or decorative layers during the bonding process while enabling furniture panel production.

Inventive Principle:
Principle #10Preliminary action

4Illumination intensity

If the top layer is made transparent with high light transmittance, then glass appearance is improved, but color stability and protection of underlying layers are reduced

Engineering Contradiction:
Improvelight transmittanceVSAvoidcolor stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent uses an intermediate layer as a mediator between the transparent top layer and the base layer. This intermediate layer can contain UV stabilizers and pigments that protect the underlying layers from degradation while allowing the transparent top layer to maintain high light transmittance for glass appearance. The intermediate layer acts as a protective barrier that preserves color stability without compromising optical properties.

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

The solution enables the production of a cost-effective, versatile multilayer composite body with excellent glass appearance and color stability, preventing distortion and ensuring economic production while maintaining mechanical and optical properties, suitable for various furniture and sanitary applications.

Implementation Method 1

The first composite panel (1) and the second composite panel (5) are connected to one another via a support element (3) arranged between the first composite panel (1) and the second composite panel (5) and/or via bonding layers (2, 4)

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

The top layer (10) consists of at least one (meth)acrylate copolymer, in particular of polymethyl methacrylate (PMMA), which has a transmittance for visible light of at least 80% over its thickness

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 3

The multilayer composite body has an intermediate layer (11), in particular a core layer, which consists of at least one (meth)acrylate copolymer and contains pigments and/or dyes and, if applicable, light stabilizers

Methodology Applied
Scientific EffectPigment absorption: Absorption (EM radiation)

Implementation Method 4

The multilayer composite body further has a lower layer (12) arranged on the intermediate layer (11), containing pigments and/or dyes and, if applicable, light stabilizers, as well as at least one styrene polymer, in particular a styrene copolymer

Methodology Applied
Scientific EffectThermal expansion matching: Thermal Expansion

Data Source

PatentEP3074227B1Multilayer composite
Publication Date: 2019.12.25 REHAU IND SE & CO KG
  • EP3074227B1 patent drawingFigure 1

AI summary

The invention relates to a multilayer composite comprising a first composite sheet (1) with an upper layer (11) made of at least one (meth)acrylate copolymer, the coefficient of linear expansion of which is about 7 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, an intermediate layer (12) made of at least one (meth)acrylate copolymer, containing pigments and/or dyes and optionally light stabilizers, this consisting of a (meth)acrylate copolymer which is the same as or different from the upper layer (11) with coefficient of linear expansion about 6.5 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, a lower layer (13), containing pigments and/or dyes and optionally light stabilizers, and also at least one styrene polymer, more particularly styrene copolymer, the coefficient of linear expansion of which is about 7 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, where the total thickness of the first composite sheet (1) is at least 1 mm and the coefficient of linear expansion of the material of the first composite sheet (1) is about 5 to 7 x 10-5 K-1 measured in accordance with ISO 11359, a second composite sheet (5) with a first layer (50) made of at least one styrene polymer, more particularly styrene copolymer with coefficient of linear expansion about 6.5 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, a second layer (51) made of at least one styrene polymer, more particularly styrene copolymer, or at least one (meth)acrylate copolymer and/or a mixture of these with coefficient of linear expansion about 6.5 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, a third layer (52) made of at least one styrene polymer, more particularly styrene copolymer with coefficient of linear expansion about 6.5 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, or at least one (meth)acrylate copolymer with coefficient of linear expansion about 7 to 9.5 x 10-5 K-1 measured in accordance with ISO 11359, where the total thickness of the second composite sheet (5) is at least 1 mm and the coefficient of linear expansion of the material of the second composite sheet (5) is about 5 to 7 x 10-5 K-1 measured in accordance with ISO 11359, a supportive element (3) arranged between the first composite sheet (1) and the second composite sheet (5) by way of at least one connecting layer (2, 4), where the connecting layer (2, 4) comprises at least one reactive hot-melt adhesive based on polyurethane (PUR), the quantity applied thereof being about 30 to 150 g/m2, preferably 40 to 80 g/m2.