Nanofiber sheet, process for producing the same, and fiber-reinforced composite material

A technology of nanofibers and manufacturing methods, applied in the field of nanofiber non-woven fabrics and its manufacturing, can solve the problem of simultaneously achieving high transparency, low linear thermal expansion coefficient, high Young's modulus, and linear thermal expansion coefficient of fiber-reinforced composite materials Large size, poor heat resistance of nanofibers, etc., to achieve high strength, excellent heat resistance, and low specific gravity

Active Publication Date: 2009-09-16
MITSUBISHI RAYON CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, there is no lignin residue, so the action similar to plasticizer by lignin between fibers cannot be expected
Therefore, the efficiency of mechanical fiber opening is poor
[0020] Therefore, for nanofibers derived from pulp and cotton, it is difficult to simultaneously achieve high transparency with low linear thermal expansion coefficient and high Young's modulus when they are combined with transparent resin to form a transparent composite material
[0021] In addition, even with the fine fibers described in Japanese Patent Application Laid-Open No. 2003-155349, repeated 10 to 20 times of fiber opening in an attempt to make them finer, the result was that the linearity of the obtained fiber-reinforced composite material was deteriorated due to the destruction of crystalline cellulose. Larger coefficient of thermal expansion
In addition, in Japanese Patent Laid-Open No. 2003-155349, as the reason for such repeated fiber opening, it is considered in Japanese Patent Laid-Open No. 2003-155349 that since lignin is not removed before fiber opening, the gap between nanofibers The hydrogen bond is more developed, as mentioned above, there will be no porosity of the fiber caused by the void after the lignin is removed, resulting in poor fiber opening efficiency
Also, as mentioned above, the heat resistance of nanofibers from which lignin has not been removed is poor, and if exposed to high temperature conditions, residual lignin, etc. will discolor even in an inert atmosphere or a vacuum atmosphere

Method used

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  • Nanofiber sheet, process for producing the same, and fiber-reinforced composite material
  • Nanofiber sheet, process for producing the same, and fiber-reinforced composite material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0357] Degreasing of radiata pine-derived wood flour (longer diameter: 500 μm, longer diameter / shorter diameter ratio: 10, moisture content: 5% by weight) with a mixture of ethanol and benzene (ethanol:benzene = 1 volume:2 volume) For processing, put 10 g of the wood powder into a solution of 600 ml of distilled water, 4 g of sodium chlorite, and 0.8 ml of glacial acetic acid, and heat it for 1 hour in a hot water bath at 70° C. to 80° C. with stirring from time to time. After 1 hour, without cooling, 4 g of sodium chlorite and 0.8 ml of glacial acetic acid were added for repeated treatment. Do this 5 times.

[0358] This is followed by washing with about 5 L of cold water and about 500 ml of acetone.

[0359] Next, 10 g of the wood flour was immersed in a 5% by weight potassium hydroxide aqueous solution, left overnight at room temperature, and then recovered by suction filtration, and washed with about 2 L of water until neutral.

[0360] After such operation, the wood flo...

Embodiment 2

[0388] In Example 1, in the manufacture of the nanofiber sheet, the following acetylation treatment A was performed on the obtained water-containing nanofiber sheet, and the manufacture of the nanofiber sheet and the fiber For the manufacture of reinforced composite materials, the measurement results of various physical properties are listed in Table 2.

[0389]

[0390]1) Cold press the water-containing nanofiber sheet (10cm×10cm) at room temperature at 2MPa for 1 minute to remove water and form a sheet with a thickness of 1mm.

[0391] 2) The pressed nanofiber sheet was immersed in acetone to completely remove the water inside the nanofiber sheet. The obtained solvent-substituted nanofiber sheet was hot-pressed at 110° C. and 2 MPa for 3 minutes.

[0392] 3) 3 mL of butyric anhydride, 40 mL of acetic acid, 50 mL of toluene, and 0.2 mL of 60% by weight perchloric acid were added to a detachable flask to prepare a reaction solution.

[0393] 4) Dip the nanofiber sheet prod...

Embodiment 3

[0396] In Example 1, in the manufacture of the nanofiber sheet, the following acetylation treatment B was performed on the obtained water-containing nanofiber sheet, and the manufacture of the nanofiber sheet and the fiber For the manufacture of reinforced composite materials, the measurement results of various physical properties are listed in Table 2.

[0397]

[0398] 1) The water-containing nanofiber sheet (10cm×10cm) was hot-pressed at 120° C. and 2 MPa for 4 minutes to completely remove the water to form a dry nanofiber sheet with a thickness of 40 μm.

[0399] 2) 3 mL of butyric anhydride, 40 mL of acetic acid, 50 mL of toluene, and 0.2 mL of 60% by weight perchloric acid were added to a detachable flask to prepare a reaction solution.

[0400] 3) The nanofiber sheet produced in 2) was immersed in the reaction solution prepared in 3), and reacted at room temperature for 1 hour.

[0401] 4) After the reaction is terminated, the obtained acetylated nanofiber sheet is w...

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Abstract

Provided is a nanofiber sheet that sufficiently refined by fibrillation and has high crystallinity of cellulose fiber and can realize a fiber-reinforced composite material exhibiting high transparency, a high elastic modulus, a low coefficient of linear thermal expansion, and high heat resistance and being high in flatness and smoothness. This nanofiber sheet includes crystalline cellulose as the main component and a lignin in an amount of from 10 ppm to 10 wt%. When a fiber / resin composite material obtained by impregnating the nanofiber sheet with tricyclodecane dimethacrylate, subjecting the impregnated product to UV-curing at 20 J / cm 2 , and heating the cured product in vacuum at 160 DEG C for two hours includes 60 wt% of the cured tricyclodecane dimethacrylate and 40 wt% of nanofiber, the following physical characteristics (i) to (iii) are satisfied: (i) the parallel light transmittance of light of a wavelength of 600 nm at a sheet thickness of 100 [mu]m is 70% or more; (ii) the Young's modulus is 5.0 GPa or more; and (iii) the coefficient of linear thermal expansion is 20 ppm / K or less.

Description

technical field [0001] The present invention relates to a nonwoven fabric of nanofibers (hereinafter referred to as "nanofiber sheet") and a method for producing the same. [0002] The present invention also relates to a fiber-reinforced composite material obtained by impregnating the nanofiber sheet with a matrix material. Background technique [0003] As the most common fiber-reinforced composite material, a glass fiber-reinforced resin obtained by impregnating glass fibers with a resin is known. Such glass fiber-reinforced resins are generally opaque materials, but Patent Document 1 and Patent Document 2 below disclose a method for obtaining a transparent glass fiber-reinforced resin by matching the refractive index of glass fibers with that of a matrix resin. [0004] However, low thermal expansion, high strength, high elasticity, light weight, etc. are required for transparent flexible substrates for mounting LEDs, organic electronic devices. However, although glass f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H11/08C08J5/04
CPCH05K2201/0284H05K2201/0251D21H11/08H05K1/0366Y10T442/2869B27N3/04B27N3/002C08J5/04
Inventor 矢野浩之能木雅也伊福伸介阿部贤太郎半田敬信
Owner MITSUBISHI RAYON CO LTD
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