Transparent Substrate

Abstract

The present invention provides a formed article, or more specifically a transparent substrate, which effectively utilizes a natural stuff and which has a low linear expansion coefficient, a high light transmittance and an appropriate level of moisture permeability. The transparent substrate includes at least an oxidized polysaccharide and has a linear expansion coefficient of 50 ppm / ° C. or less at 30-150° C. and a light transmittance of 70% or more at 660 nm. Its manufacturing method includes an oxidation process in which cellulose reacts with TEMPO or its derivatives as a catalyst to be oxidized in water under the presence of a co-oxidant, along with a fiberizing process in which the oxidized cellulose is fiberized in water to form a cellulose fiber, and a substrate-forming process in which a transparent substrate is formed from a cellulose dispersion liquid containing the cellulose fiber.

Description

[0001] This application is a continuation of International Application No. PCT / JP2011 / 069009, filed Aug. 24, 2011, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a transparent substrate which includes a natural stuff. More specifically, the present invention relates to a transparent substrate which includes a cellulose fiber having a substituted group.

[0004] 2. Description of the Related Art

[0005] In recent years, much research has been conducted on natural stuffs available for use as a transparent substrate as an alternative to a triacetyl cellulose (TAC) film. While it has been, for example, found that it is possible to make remarkably fine cellulose nanofibers from cellulose fibers by a chemical and / or mechanical treatment, it has further been found that a formed article having robustness and a low linear expansion coefficient can be obtained from a composite material in which...

Examples

examples

[0093]Examples of the present invention are described below. These are only examples, and therefore, the present invention is not limited to these.

preparation example

[0094]TEMPO oxidation of cellulose is carried out according to the following procedure.

Chemicals and Materials

[0095]Natural cellulose: bleached kraft pulp (“Mackenzie”, I-type crystalline, Fletcher Challenge Canada Ltd.).[0096]TEMPO: commercial item (98%, Tokyo Chemical Industry Co., Ltd.).[0097]Sodium hypochlorite: commercial item (Cl: 5%, Wako Pure Chemical Industries, Ltd.).[0098]Sodium chlorite: commercial item (79%, Kanto Chemical Co., Inc.).[0099]Sodium bromide: commercial item (Wako Pure Chemical Industries, Ltd.).

TEMPO Oxidation Treatment of Cellulose

[0100]10 g (dry weight) of the bleached kraft pulp was statically immersed in 500 ml of ion-exchange water in a 2 L-glass beaker and left over night to swell with water. After this was kept at 20° C. with a temperature-controlled water bath, 0.1 g of TEMPO and 1 g of sodium bromide were added under stirring so that pulp slurry was obtained. Subsequently, 5 mmol of sodium hypochlorite with respect to 1 g of cellulose was added t...

examples 1-4

[0113]The cellulose dispersion liquid obtained in in the section of > was casted on a polystyrene plate and dried at 50° C. in an oven for 24 hours to form films having a thickness of 20 μm (in example 1), 40 μm (in example 2), 60 μm (in example 3) and 250 μm (in example 4).

[0001] This application is a continuation of International Application No. PCT / JP2011 / 069009, filed Aug. 24, 2011, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a transparent substrate which includes a natural stuff. More specifically, the present invention relates to a transparent substrate which includes a cellulose fiber having a substituted group.

[0004] 2. Description of the Related Art

[0005] In recent years, much research has been conducted on natural stuffs available for use as a transparent substrate as an alternative to a triacetyl cellulose (TAC) film. While it has been, for example, found that it is possible to make remarkably fine cellulose nanofibers from cellulose fibers by a chemical and / or mechanical treatment, it has further been found that a formed article having robustness and a low linear expansion coefficient can be obtained from a composite material in which...

Examples

examples

[0093]Examples of the present invention are described below. These are only examples, and therefore, the present invention is not limited to these.

preparation example

[0094]TEMPO oxidation of cellulose is carried out according to the following procedure.

Chemicals and Materials

[0095]Natural cellulose: bleached kraft pulp (“Mackenzie”, I-type crystalline, Fletcher Challenge Canada Ltd.).[0096]TEMPO: commercial item (98%, Tokyo Chemical Industry Co., Ltd.).[0097]Sodium hypochlorite: commercial item (Cl: 5%, Wako Pure Chemical Industries, Ltd.).[0098]Sodium chlorite: commercial item (79%, Kanto Chemical Co., Inc.).[0099]Sodium bromide: commercial item (Wako Pure Chemical Industries, Ltd.).

TEMPO Oxidation Treatment of Cellulose

[0100]10 g (dry weight) of the bleached kraft pulp was statically immersed in 500 ml of ion-exchange water in a 2 L-glass beaker and left over night to swell with water. After this was kept at 20° C. with a temperature-controlled water bath, 0.1 g of TEMPO and 1 g of sodium bromide were added under stirring so that pulp slurry was obtained. Subsequently, 5 mmol of sodium hypochlorite with respect to 1 g of cellulose was added t...

examples 1-4

[0113]The cellulose dispersion liquid obtained in in the section of > was casted on a polystyrene plate and dried at 50° C. in an oven for 24 hours to form films having a thickness of 20 μm (in example 1), 40 μm (in example 2), 60 μm (in example 3) and 250 μm (in example 4).