Sheet-shaped object and process for producing same
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sheet-like articles fail to achieve a balance between being thin, high-strength, and having a dense, soft-to-the-touch surface, with previous methods either compromising on strength or surface quality due to challenges in controlling elastic polymer distribution and fiber density.
Innovation Solution
A sheet-like article comprising ultrafine fibers with a specific diameter range and an elastic polymer containing polyurethane, where the fiber density and elastic polymer density are strategically distributed across the thickness to create a dense, soft surface with high strength, achieved through a production method involving nonwoven fabric preparation, impregnation, and controlled napping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elastic polymer is localized near the surface region to achieve high strength and pilling resistance, then strength and pilling resistance are improved, but surface quality deteriorates with rough feel and short raised fibers
Solution Approach 1:
The patent applies local quality by creating distinct regions within the sheet thickness: the first region (near surface) has high elastic polymer content for strength and pilling resistance, while the second region (deeper interior) has high fiber content for napping quality and surface smoothness. This spatial differentiation of material composition resolves the contradiction between strength and surface quality.
Solution Approach 2:
The patent transitions from two-dimensional surface treatment to three-dimensional volumetric distribution by controlling the depth-wise arrangement of fibers and elastic polymer. By manipulating the third dimension (thickness direction), it achieves both surface strength and interior napping quality simultaneously.
2Adaptability or versatility
If thin sheets are produced to meet diversifying needs, then adaptability is improved, but strength deteriorates due to insufficient elastic polymer localization control
Solution Approach 1:
The patent employs parameter changes by precisely controlling the depth position, thickness, and material composition ratios of the first and second regions. By adjusting these parameters, it achieves effective elastic polymer localization even in thin sheets, maintaining strength while enabling diverse thin-sheet applications.
3Strength
If high-strength woven fabric is inserted into nonwoven fabric to increase strength, then strength is improved, but thickness increases making thin products difficult
Solution Approach 1:
The patent creates a composite structure where ultrafine fibers and elastic polymer form an integrated matrix without requiring separate woven fabric layers. The elastic polymer binds fibers together to provide strength, while the ultrafine fiber diameter (0.1-7 μm) enables thin overall thickness, avoiding the thickness penalty of inserted woven fabrics.
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 results in a sheet-like article that is both thin and strong, with a dense, soft surface and excellent abrasion resistance, suitable for various applications while maintaining practical physical properties.
Implementation Method 1
an elastic polymer containing polyurethane as primary component... the ultrafine fibers being held by the elastic polymer
Implementation Method 2
impregnation with a solution or aqueous dispersion of an elastic polymer
Data Source
AI summary
A sheet-shaped object which is thin and, despite this, has a surface that is dense and is soft to the touch and which has practicable strength and a process for producing the sheet-shaped object are disclosed. This sheet-shaped object comprises ultrafine fibers having an average single-fiber diameter of 0.1-7 μm and a polymeric elastomer comprising a polyurethane as a major component, wherein when a layer extending from one surface to a depth of 50% of the thickness is referred to as layer (A) and a layer extending from the other surface to a depth of 50% of the thickness is referred to as layer (B), then the ratio of the density of fibers (A′) in the layer (A) to the density of fibers (B′) in the layer (B) satisfies the following expression (a) and the ratio of the density of the polymeric elastomer comprising a polyurethane as a major component (A″) in the layer (A) to the density thereof (B″) in the layer (B) satisfies the following expression (b). The sheet-shaped object as a whole has a density of 0.2-0.6 g/cm3. 1>(A′)/(B′)≧0.5 (a) 1>(A″)/(B″)≧0.6 (b).