JP7582901B2 - Sheet and method for manufacturing the sheet - Google Patents

Description

This disclosure relates to a sheet and a method for manufacturing the sheet.

Conventional wood boards are made by cutting biomass (mainly wood) into chips or powder and mixing it with resin and adhesive. Because wood boards are light and strong, they are widely used for furniture and home interiors.
However, the adhesives used in conventional wood boards release volatile components such as formaldehyde, which can potentially cause sick house syndrome.
Meanwhile, methods for culturing plant cells have been investigated (see, for example, Patent Document 1).
However, the uses of plant cells are limited, and the development of new uses for plant cells has been desired.

Japanese Unexamined Patent Publication No. 62-55077

This disclosure was made in consideration of the above-mentioned circumstances, and aims to obtain a sheet that effectively utilizes cultured plant cells and does not cause sick house syndrome. This disclosure can be realized in the following forms.

A sheet formed by heat pressing cultured plant cells.

The sheet disclosed herein allows for the effective use of plant cells. Moreover, this sheet does not cause sick house syndrome.

FIG. 1 is a perspective view showing an example of a sheet.

Here, a preferred example of the present disclosure is given.
The sheet preferably does not contain synthetic resin.
The sheet preferably comprises a polysaccharide.
The sheet preferably comprises lignin.
The sheet is preferably produced by heat pressing the cultured plant cells.

The present disclosure is described in detail below. In this specification, when a numerical range is described using "to" it is intended to include the lower limit and the upper limit unless otherwise specified. For example, the description "10 to 20" is intended to include both the lower limit "10" and the upper limit "20". In other words, "10 to 20" has the same meaning as "10 or more and 20 or less".

1. Sheet The sheet of the present disclosure is formed by heat pressing cultured plant cells. The thickness and shape of the sheet are not particularly limited.
(1) Cultured plant cells The cultured plant cells are not particularly limited. From the viewpoint of easy availability, etc., it is preferable to use one or more types of cultured plant cells selected from the group consisting of bamboo cells and kenaf cells.
(2) Raw materials other than cultured plant cells Raw materials other than cultured plant cells may be used. It is preferable that the sheet be made only from cultured plant cells.
In addition, other than the cultured plant cells, inappropriate raw materials include, for example, organic solvents, petroleum-derived components, etc. Adding these components may cause sick house syndrome.
(3) Components of the Sheet The sheet contains components derived from cultured plant cells. Examples of the components include polysaccharides, proteins, and lignin (an example of a phenolic component).
Examples of polysaccharides include cell wall polysaccharides. Examples of polysaccharides include cellulose, hemicellulose such as xyloglucan, and pectin. The content of polysaccharides in the sheet is not particularly limited. The content of polysaccharides is preferably 20% by weight or more and 80% by weight or less, more preferably 30% by weight or more and 70% by weight or less, and even more preferably 40% by weight or more and 60% by weight or less, based on 100% by weight of the entire sheet, from the viewpoint of sheet strength.
The lignin content in the sheet is not particularly limited. From the viewpoint of sheet strength, the lignin content is preferably 0.1% by weight or more and 20% by weight or less, more preferably 0.5% by weight or more and 15% by weight or less, and even more preferably 1% by weight or more and 10% by weight or less, based on 100% by mass of the entire sheet.
It is preferable that the sheet does not contain synthetic resin.

2. Sheet Manufacturing Method (1) Heat Pressing Step The sheet manufacturing method of the present disclosure includes a step of heat pressing the cultured plant cells. The conditions of the heat pressing are not particularly limited.
The temperature of the heat press is not particularly limited. From the viewpoint of softening the cultured plant cells to make them easily moldable into a sheet and suppressing discoloration of the sheet, the temperature of the heat press is preferably 100° C. or more and 130° C. or less, and more preferably 110° C. or more and 120° C. or less.
The pressure of the heat press is not particularly limited. From the viewpoint of sufficiently crushing the plant cultured cells to form them into a sheet, the pressure of the heat press is preferably 2 MPa to 10 MPa, more preferably 3 MPa to 7 MPa. It is preferable to gradually increase the pressure over a period of 3 hours to 8 hours until the pressure of the heat press is reached. By gradually increasing the pressure, the multiple plant cultured cells can be sufficiently blended with each other and easily adhered to each other.
The time for the heat press is not particularly limited. From the viewpoint of sufficiently crushing the cultured plant cells and forming them into a sheet, the time for the heat press is preferably from 1 hour to 72 hours, more preferably from 12 hours to 36 hours, after the predetermined temperature and pressure are reached.

(2) Other steps (optional steps)
The sheet manufacturing method may further include a step of culturing cultured plant cells as another step.
The sheet manufacturing method may further include a step of filtering or drying (preferably freeze-drying) the culture solution containing the cultured plant cells.

3. Effects of the Sheet of the Present Disclosure If the sheet of the present disclosure uses only cultured plant cells as the raw material, the constituent components of the sheet will be only natural components, and will not contain additives such as organic solvents or adhesives. In this case, no organic solvents or other petroleum-derived components that cause sick house syndrome are used, making it a promising next-generation eco-material.
Furthermore, if the cultivation of plant cultured cells could be made into a process with less environmental impact, they would be highly valuable as next-generation eco-materials.
Furthermore, the sheet of the present disclosure allows for the effective use of plant cells.

4. Effects of the Manufacturing Method of the Sheet of the Present Disclosure According to the manufacturing method of the present disclosure, it is possible to obtain a sheet that effectively utilizes cultured plant cells in a simple manner and does not cause sick house syndrome.

The present disclosure will now be described more specifically with reference to examples.
1. Experimental Method A sheet was formed as follows.
(1) Plant cells were cultured. Bamboo cells and kenaf cells were used as plant cells.
(2) The plant culture cells and the culture solution were separated by filtration to obtain only the plant culture cells.
(3) The plant culture cells were placed in a mold (stainless steel frame). At this time, in order to make it easier to place the plant culture cells in the mold, water may be added to the plant culture cells and then poured into the mold.
(4) The mold containing the plant culture cells was placed in a heat press and the temperature was adjusted to 110°C to 120°C.
(5) Pressure was gradually applied until it reached 5 MPa, after which it was hot pressed for 24 hours.
(6) After that, it was confirmed that the temperature and pressure had returned to normal, and the sheet (plate) was then removed from the mold.

<Heat press conditions>
Pressure: 5 MPa
Temperature: 110-120°C Time: 5MPa, 24 hours after reaching 120°C

2. Analysis of components The components were analyzed. The analysis results are shown in Table 1. Here, the plant cultured cells, the raw material of the sheet, were analyzed. The sheet is made by heat pressing the plant cultured cells, and the components do not change due to the heat pressing, so the ratio of each component in the sheet is the same as the component ratio of the plant cultured cells.
The component analysis was carried out as follows.
(1) Cell Culture Plant cells to serve as cell samples were cultured.
(2) The cell samples were filtered, washed, and then freeze-dried, which allowed them to be washed and dried for component analysis.
(3) Component analysis (3.1) Weight measurement 1
The weight of the cell sample was measured before component analysis. This weight was designated as "Weight 1."
(3.2) Hot water extraction The cell sample was extracted with hot water to remove mainly proteins, free sugars, and inorganic substances. The cell sample, the weight of which was measured, was placed in hot water and stirred for 3 hours. After processing, the cell sample was filtered and dried.
(3.3) Acetone Extraction Lipids were mainly removed from the cell sample after hot water treatment by acetone extraction. Specifically, the cell sample was placed in acetone and stirred for 8 hours. After treatment with acetone, the cell sample was filtered and dried.
(4) Weight measurement 2
The weight of the cell sample after extraction with hot water and acetone was measured. This weight was designated as "Weight 2." After extraction, the cell sample consisted only of cell wall components.
(5) Sulfuric acid method The amount of lignin was measured by the sulfuric acid method, which is a method in which polysaccharides in the cell walls of a cell sample are hydrolyzed with acid and the amount of remaining lignin is measured.
(5.1)
72% sulfuric acid was added to the cell sample and stirred at room temperature for 1 hour.
(5.2)
Water was added to the cell sample so that the sulfuric acid concentration became 3%, and the mixture was stirred at 100° C. for 3 hours.
(5.3)
After filtering and drying the residue overnight in an oven at 105° C., the cell sample was weighed. This weight was designated as “Weight 3.”
(6) How to calculate the amount of components Extracted component amount (wt%) = ((weight 1) - (weight 2)) ÷ (weight 1) x 100
The amounts of extracted components include proteins, free sugars, lipids, and other components.

Lignin component amount (wt%) = (weight 3) ÷ (weight 1) × 100

Polysaccharides (polysaccharide components in cell walls) (wt%)
= 100 - amount of extracted components (wt%) - amount of lignin components (wt%)

3. Effects of the Examples The sheets of the Examples use only plant cultured cells as raw materials, so the constituent components of the sheets are only natural components, and do not contain additives such as organic solvents or adhesives. Therefore, these sheets do not use organic solvents or other petroleum-derived components that cause sick house syndrome, and are therefore expected to be next-generation eco-materials.
Furthermore, the sheets of the examples are expected to be a new application for cultured plant cells.

The foregoing examples are merely illustrative and are not to be construed as limiting the present disclosure. While the present disclosure has been described with reference to exemplary embodiments, the words used in describing and illustrating the present disclosure are understood to be descriptive and exemplary, rather than limiting. As detailed herein, changes may be made within the scope of the appended claims without departing from the scope or nature of the present disclosure in its form. Although the detailed description of the present disclosure has referred to specific structures, materials, and examples, it is not intended that the present disclosure be limited to those disclosed herein, but rather that the present disclosure extends to all functionally equivalent structures, methods, and uses within the scope of the appended claims.

This disclosure is not limited to the embodiments detailed above, and various modifications and variations are possible within the scope of the claims of this disclosure.

1 ... sheet

Claims (5)

A sheet formed by heat pressing a plurality of plant cultured cells without using a synthetic resin as an admixture, the plurality of plant cultured cells being adhered to each other, and the sheet not containing the synthetic resin . The sheet according to claim 1 , wherein the cultured plant cells are selected from the group consisting of bamboo cells and kenaf cells . The sheet according to claim 1 or claim 2, which contains a polysaccharide. A sheet according to any one of claims 1 to 3, comprising lignin. A method for producing the sheet according to any one of claims 1 to 4, comprising the steps of:
The method for producing a sheet comprises heat-pressing the cultured plant cells.

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