Composite sheet and manufacturing method for a foamed decorative sheet free of PVC and plasticizers
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Solution Overview
Problem
Existing composite sheets used in decorative wall coverings experience significant curling due to differing thermal expansion properties of the base and foamable layers, making large-scale production impossible.
Innovation Solution
A composite sheet comprising a base layer with an elastic modulus of >1 GPa and a foamable layer with an elastic modulus of <0.1 GPa, along with a thickness of 0.05 to 0.3 mm, is used to minimize curling, allowing for a curling-free production of large decorative sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a composite sheet with a base layer and foamable layer is used, then the sheet provides wear resistance, washability, and longevity, but significant curling occurs due to different thermal expansion properties of the layers
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the base layer (0.1-0.5 mm) and foamable layer (0.05-0.3 mm), and by selecting materials with specific elastic moduli (base layer: 1-10 GPa, foamable layer: 0.1-1 GPa) to minimize thermal expansion differences and prevent curling while maintaining wear resistance and dimensional stability
Solution Approach 2:
The patent uses composite materials by combining a base layer made of paper, non-woven fabric, or foam with a foamable layer made of thermoplastic polymer, creating a multi-layer structure that integrates the dimensional stability of the base layer with the foaming properties of the thermoplastic layer, thereby achieving both wear resistance and dimensional stability
2Productivity
If the foamable layer thickness is increased to produce thicker decorative sheets, then production cost decreases, but curling becomes more severe
Solution Approach 1:
The patent applies parameter changes by optimizing the foamable layer thickness within the range of 0.05-0.3 mm and adjusting the elastic modulus of the foamable layer to 0.1-1 GPa, which allows producing thicker decorative sheets at lower cost while minimizing curling through controlled material properties and layer dimensions
3Strength
If PVC is used as the foamable material, then the sheet achieves required strength and flexibility, but harmful plasticizers and stabilizing agents migrate to the environment
Solution Approach 1:
The patent applies parameter changes by replacing PVC with thermoplastic polymers having specific elastic modulus (0.1-1 GPa) and melting point (80-150°C) characteristics, which provide the required strength and flexibility without containing harmful plasticizers and stabilizing agents, thereby eliminating harmful migration while maintaining mechanical properties
Solution Approach 2:
The patent uses composite materials by creating a foamable layer from thermoplastic polymer combined with foamable agents and optional additives, forming an eco-friendly composite that achieves the necessary strength and flexibility without the harmful substances associated with PVC, thus resolving the contradiction between strength and harmful migration
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 curling-free decorative sheets of large dimensions in a continuous manner, improving dimensional stability and enabling effective printing and embossing processes.
Implementation Method 1
foaming the sheet and further processing like structure embossing, cutting, packing
Implementation Method 2
Curling occurs due to the different thermal expansion of diverse materials and depends on the mechanical and thermal expansion properties of each layer
Data Source
AI summary
A composite sheet and a method for producing a decorative sheet using the composite sheet are provided. The composite sheet has a base layer and a foamable layer bonded to the base layer. The foamable layer includes 100 parts by weight of a polyolefin material having an elastic modulus of <0.1 GPa, 0.1-10 parts by weight of a foaming agent, and 0-200 parts by weight of additives. The foamable layer has a thickness of 0.05 to 0.3 mm.