Multilayer Decorative Sheet for Curved-Surface Moldability
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Solution Overview
Problem
Existing decorative sheets face challenges with moldability on curved surfaces, high manufacturing costs, and lack of scratch resistance, particularly due to limitations with polyvinyl chloride (PVC) and polyethylene terephthalate (PET) sheets, which generate endocrine disruptors and have restricted moldable temperature ranges.
Innovation Solution
A decorative sheet comprising a top and rear surface layer formed from a glycol-modified polyethylene terephthalate resin blend with an ester-based resin, and an intermediate layer containing polyethylene terephthalate resin, offering a low and wide moldable temperature range, excellent printability, and high scratch resistance, while avoiding the use of PVC and reducing manufacturing costs through the inclusion of PET resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyvinyl chloride (PVC) sheets are used as decorative sheets, then low price and excellent processability are achieved, but a large amount of dioxin is generated upon burning which is harmful to human health
Solution Approach 1:
The invention extracts and removes the harmful PVC material from the decorative sheet composition entirely, replacing it with polyester-based materials (PET and PETG) that do not generate dioxin when burned, while maintaining the desired processability and manufacturing advantages
Solution Approach 2:
The invention uses cost-effective polyester materials (PET and PETG) as alternatives to PVC, achieving similar manufacturing ease and processability without the harmful environmental and health effects, making the decorative sheets economically viable and environmentally friendly
2Object-generated harmful factors
If polyethylene terephthalate (PET) sheets are used to replace PVC, then environmentally friendly properties are achieved, but high molding temperature and narrow molding temperature range result in poor moldability
Solution Approach 1:
The invention creates a composite structure combining PET and PETG materials in specific layers. The PETG component has a broader and lower molding temperature range that enables excellent moldability on curved surfaces, while the PET component provides environmental friendliness. This composite approach allows the material to be molded at lower temperatures with a wider temperature window, resolving the poor moldability issue
Solution Approach 2:
The invention changes the thermal parameters of the decorative sheet material by using PETG (with lower glass transition temperature) instead of pure PET. This parameter change lowers the molding temperature requirement and broadens the molding temperature range, enabling excellent moldability while maintaining environmental friendliness
3Shape
If PET sheets are used for decorative applications, then high quality surface is achieved, but limitations in coating for improving hardness and high rate of defects due to crystallization occur
Solution Approach 1:
The invention uses a composite of PET and PETG where the amorphous PETG component prevents crystallization defects during coating processes. This composite structure maintains the high-quality surface characteristics while eliminating the crystallization issues that plague pure PET sheets, enabling reliable hard coating application
Solution Approach 2:
The invention replaces problematic pure PET sheets with a PET/PETG composite that avoids crystallization defects, enabling successful coating applications for improving surface hardness without the high defect rates associated with crystallization in pure PET
4Ease of manufacture
If PET sheets employ a large amount of additives to improve moldability, then moldability is enhanced, but uniform printability cannot be secured
Solution Approach 1:
The invention changes the fundamental approach to improving moldability by using PETG's inherent lower glass transition temperature and broader processing window rather than adding large amounts of additives to PET. This parameter change enables excellent moldability on curved surfaces while maintaining the material's ability to accept uniform prints without the need for excessive additives that would compromise printability
Data Source
AI summary
Provided is a decorative sheet which comprises a top surface layer, a rear surface layer and at least one intermediate layer between the top surface layer and the rear surface layer, wherein: the top surface layer and the rear surface layer each independently are formed from a first composite resin composition comprising a glycol-modified polyethylene terephthalate resin and an ester-based resin; the intermediate layer(s) is (are) formed from a second composite resin composition comprising a glycol-modified polyethylene terephthalate resin, a polyethylene terephthalate resin and an ester-based resin; the glass-transition temperature of the ester-based resin is lower than the glass-transition temperature of the glycol-modified polyethylene terephthalate resin; the glass-transition temperature of the ester-based resin is lower than the glass-transition temperature of the polyethylene terephthalate resin; and the content of the polyethylene terephthalate resin in the second composite resin composition is between about 5 and about 30 wt %.