Decorative Sheet Surface Unevenness and Curling Resistance
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Solution Overview
Problem
Decorative sheets for floors face challenges in Europe due to vinyl chloride-based resin regulations, requiring alternatives that can be bonded to chipboards without showing surface unevenness, maintaining embossing properties, resisting scratches, and curling resistance, while allowing roll laminating.
Innovation Solution
A decorative sheet with a base material sheet, a transparent resin layer, and a surface-protecting layer, where the surface-protecting layer contains specific fine particles and is embossed from the surface-protecting layer side, using non-halogen-based thermoplastic resins, and a backer layer with specific thickness and hardness, laminated by extrusion molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the decorative sheet is increased to enhance surface smoothness, then surface unevenness is suppressed, but emboss-forming properties are reduced
Solution Approach 1:
The decorative sheet is divided into multiple functional layers: a base material sheet (180-350 μm) providing structural support and smoothness, and a surface-protecting layer (7-30 μm) containing embossed patterns. This segmentation allows each layer to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different regions of the decorative sheet have different properties: the base material sheet has uniform thickness and smoothness for suppressing adherend unevenness, while the surface-protecting layer has localized embossed patterns for designability and scratch resistance. This local differentiation resolves the contradiction between overall smoothness and localized embossing.
2Adaptability or versatility
If the embossed shape is made shallow to maintain designability, then designability is improved, but embossing collapse occurs when bonded to adherend
Solution Approach 1:
The decorative sheet uses a composite structure where the base material sheet (olefinic resin) and surface-protecting layer (ionizing radiation-curable resin) have different mechanical properties. The base layer provides rigidity to prevent embossing collapse, while the surface layer maintains designability with shallower embossed patterns.
3Manufacturing precision
If the thickness of the decorative sheet is increased to suppress surface unevenness, then surface smoothness is improved, but curliness occurs when stored in rolled state
Solution Approach 1:
The decorative sheet segments the smoothness function into the base material sheet (180-350 μm) while keeping the total thickness controlled. This allows the base layer to suppress adherend unevenness without excessive total thickness that would cause curling during storage and roll laminating.
4Manufacturing precision
If vinyl chloride-based resin is used for bonding to achieve good bonding finish, then bonding quality is improved, but environmental regulations are violated and productivity is reduced
Solution Approach 1:
The patent changes the material parameter from vinyl chloride-based resin to olefinic resin (polyethylene, polypropylene) and ionizing radiation-curable resin. This substitution maintains bonding performance while enabling environmental compliance and roll laminating productivity through the non-halogenated, flexible material properties.
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 suppresses surface unevenness, maintains embossing properties, provides excellent scratch resistance, and allows for curling resistance, enabling the decorative sheet to be wound in a roll shape without strain and used under service conditions like walking.
Implementation Method 1
the surface-protecting layer contains an ionizing radiation-curable resin
Implementation Method 2
a backer layer with specific thickness and hardness, laminated by extrusion molding
Implementation Method 3
laminated by extrusion molding
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3~4
AI summary
The present invention provides decorative sheet comprising a base material sheet, and at least a transparent resin layer and a surface-protecting layer sequentially laminated on the base material sheet, and the decorative sheet comprising at least a backer layer laminated on a back surface of the base material sheet; wherein the surface roughness of the decorative sheet is within a specific range; the base material sheet, the transparent resin layer, and the surface-protecting layer each contain a specific resin; and the backer layer containing a specific resin and having specific thickness and hardness is laminated by extrusion molding. Moreover, the present invention provides a rolled product and a decorative plate each obtained from the decorative sheet as well as a process for producing a decorative sheet and a process for producing a decorative plate.