Printed napped sheet and napped sheet for printing
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Solution Overview
Problem
Napped sheets, such as suede-like artificial leather, often develop spot-like defects when printed due to fibers being erected, causing shadowed areas to remain uncolored.
Innovation Solution
A printed napped sheet with a napped surface having a surface roughness of 30 μm or less, a peak density of 30/432 mm² or less, and a peak difference of 20/432 mm² or less in both grain and reverse grain directions, using elastic polymers to fix fibers and adjust surface properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the napped surface is printed with ink, then the design is formed on the surface, but spot-like defects appear when fibers are erected during rubbing
Solution Approach 1:
The patent applies a fixing agent to the napped surface before printing to pre-treat the fibers. This preliminary action reduces fiber eriction during rubbing, preventing the shadowing effect that causes spot-like defects. The fixing agent is applied, dried, and then the surface is printed, ensuring that the fibers remain stable during the printing and subsequent use.
2Shape
If the napped surface has high fiber fluffiness for aesthetic appearance, then the surface looks elegant, but fibers are easily erected causing printing defects
Solution Approach 1:
The fixing agent is applied to the napped surface before printing to pre-reduce fiber erection. This allows the surface to maintain its aesthetic napped appearance while preventing the fibers from erecting during rubbing, which would otherwise cause shadowing and printing defects. The fixing agent treatment is performed before the printing process.
3Manufacturing precision
If the arithmetic mean height Sa is reduced to prevent fiber erection, then printing quality improves, but the napped surface characteristics may be compromised
Solution Approach 1:
The patent changes the physical-chemical parameters of the napped surface by applying a fixing agent that reduces the arithmetic mean height Sa to 30 μm or less. This parameter change stabilizes the fibers to prevent erection during rubbing, ensuring printing quality while maintaining the essential napped surface characteristics through controlled modification.
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
Prevents fibers from being raised, reducing the likelihood of spot-like defects even when rubbed, ensuring uniform coloration.
Implementation Method 1
the fabric includes a first elastic polymer attached to the napped surface
Data Source
AI summary
Disclosed is a printed napped sheet or a printing sheet including a fabric having a napped surface, wherein the napped surface is printed and has, as measured by a surface roughness measurement in accordance with ISO 25178, an arithmetic mean height (Sa) of a predetermined value or less (e.g., 30 μm or less) in both a grain direction and a reverse grain direction, and the napped surface has a density of peaks (Spd), having a height of 100 μm or more from a mean height, of a predetermined value or less (e.g., 30/432 mm2 or less) in both the grain direction and the reverse grain direction. Also disclosed is a printed napped sheet wherein the napped surface has a difference (absolute value) in density of peaks (Spd), between the grain direction and the reverse grain direction, of 20/432 mm2 or less.