Sheet-shaped object and process for producing same

Patent metadata

Field	Value
Publication number	US-9739009-B2
Application number	US-201415021103-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 13, 2013
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

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/cm 3 . 1>(A′)/(B′)≧0.5 (a) 1>(A″)/(B″)≧0.6 (b).

First claim

The invention claimed is:

1. A sheet-like article comprising ultrafine fibers with an average monofilament diameter of 0.1 μm or more and 7 μm or less and an elastic polymer containing polyurethane as primary component, meeting Formula (a) given below for the ratio between the fiber density (A′) in a layer having a thickness equal to 50% of the total thickness measured from one surface of the sheet-like article, herein referred to as layer (A), and the fiber density (B′) in a layer having a thickness equal to 50% of the total thickness measured from the opposite surface of the sheet-like article, herein referred to as layer (B), meeting Formula (b) given below for the ratio between the density (A″) of the elastic polymer containing polyurethane as primary component in layer (A) and the density (B″) of the elastic polymer containing polyurethane as primary component in layer (B), and having an overall density of 0.2 g/cm 3 or more and 0.6 g/cm 3 or less for the entire sheet-like article:
1>( A ′)/( B ′)≧0.5  (a)

1>( A ″)/( B ″)≧0.6  (b).

2. A sheet-like article as claimed in claim 1 , wherein one of the surfaces contains raised ultrafine fibers while the other surface contains ultrafine fibers and an elastic polymer containing polyurethane as primary component, with the ultrafine fibers in the latter surface being held by the elastic polymer.

3. A sheet-like article as claimed in claim 1 that has a thickness of 0.2 mm or more and 0.8 mm or less.

4. A production method for a sheet-like article as claimed in claim 1 , comprising ultrafine fibers with an average monofilament diameter of 0.1 pm or more and 7 pm or less and an elastic polymer containing polyurethane as primary component, that comprises the following steps of (i) to (vi) to be carried out in this order:
(i) a step for preparing nonwoven fabric by entangling ultrafine fiber-generating fibers comprising two or more types of thermoplastic resin that differ in solubility to a solvent,
(ii) a step for impregnating the nonwoven fabric with an aqueous solution of water-soluble resin and drying it at 110° C. or more to combine it with the water-soluble resin,
(iii) a step for pressing the nonwoven fabric combined with water-soluble resin to provide a sheet,
(iv) a step for combining the sheet resulting from step (iii) above with an elastic polymer containing polyurethane as primary component by performing treatment thereof with a solvent to develop ultrafine fibers with an average monofilament diameter of 0.1 pm or more and 7 pm or less and impregnating the sheet with a solution of an elastic polymer containing polyurethane as primary component, followed by solidification, or impregnating the sheet resulting from step (iii) above with a solution of an elastic polymer containing polyurethane as primary component, followed by solidification, to combine the sheet with the elastic polymer containing polyurethane as primary component, and then treating the sheet with a solvent to develop ultrafine fibers with an average monofilament diameter of 0.1 pm or more and 7 pm or less,
(v) cutting the sheet resulting from step (iv) above in half in the thickness direction, and
(vi) napping only the non-cut surface of each half of the sheet resulting from step (v) above.

Assignees

• Toray Industries

Inventors

• Ueno Masaru
• Sumida Makoto
• Matsuzaki Yukihiro

Classifications

• D06C11/00

  Teasing, napping or otherwise roughening or raising pile of textile fabrics (for making patterns or designs D06C23/02) · CPC title

• D06N3/14 Primary

  with polyurethanes · CPC title

• D04H1/4382 Primary

  Stretched reticular film fibres; Composite fibres; Mixed fibres; Ultrafine fibres; Fibres for artificial leather · CPC title

• D06M15/564

  Polyureas, polyurethanes or other polymers having ureide or urethane links; Precondensation products forming them · CPC title

• D04H1/43838 Primary

  Ultrafine fibres, e.g. microfibres · CPC title