JP7024953B2 - Thermal pressure molded product of chemically modified lignocellulosic and its manufacturing method - Google Patents

Description

The present invention relates to a heat-press molded product of chemically modified lignocellulosic and a method for producing the same.

The heat-press molded product of the chemically modified lignocellulosic of the present invention can be produced by hot-pressing (heat-pressing) the chemically modified lignocellulosic fibers.

Lignocellulosic is a complex hydrocarbon polymer (natural polymer mixture) that constitutes a tree cell wall. It is known that lignocellulosic is mainly composed of the polysaccharide cellulose, hemicellulose and lignin which is an aromatic polymer.

Reference example 1 :
Review Article Conversion of Lignocellulosic Biomass to Nanocellulose:
Structure and Chemical Process HV Lee, SBA Hamid, and SK Zain,
Scientific World Journal Volume 2014 ,, Article ID 631013, 20 pages,
http://dx.doi.org/10.1155/2014/631013
Reference example 2 :
New lignocellulose pretreatments using cellulose solvents:
A review, Noppadon Sathitsuksanoh, Anthe George and YH Percival Zhang,
J Chem Technol Biotechnol 2013; 88: 169-180
Natural lignocellulosic has a structure in which lignin and hemicellulose are filled in the gaps between cellulose microfibril bundles (cellulose nanofibers: CNF), which is the basic skeleton. It can be said that this structure is a nanocomposite using CNF as a filler and lignin / hemicellulose as a matrix.

So far, research has been conducted on the creation of nanocomposites using the thermoplasticity of matrices while maintaining the crystallinity of cellulose by utilizing such nanostructures of wood.

In Non-Patent Document 1 of the present inventors, a slurry of Chemi-Thermo-Mechanical Pulp (CTMP) having a lignin content of 28% by mass is treated with a grinder to have a fiber diameter of 20 nm to 1 μm. It is described that microfibrillated lignocellulosic fibers were prepared and then filtered, dried and hot-pressed to give a hot-press molded product.

In Non-Patent Document 2 of the present inventors, a bleached chemi-thermo-mechanical pulp (BCTMP) was prepared by a grinder with the aim of creating a thermoplastic nanocomposite using the structure of a tree cell wall. It is described that when lignocellulose nanofibers (lignoCNF) were obtained and then selectively chemically modified (n-octanoylated) on the surface of the lignoCNF, the thermoplasticity was greatly improved.

Patent Document 1 of the present inventors describes chemically modified lignocellulosic (α-position chemically modified lignocellulosic) in which the α-position of the phenylpropane unit constituting lignin in lignocellulosic is partially chemically modified, and α-position chemical modification. Lignocellulosic (lignocellulosic double-modified form) in which the hydroxyl groups of the cellulose constituting lignocellulosic and hemicellulose are further partially chemically modified is disclosed, and a thermostatically molded body of these chemically modified lignocellulosic is also disclosed.

In the hot-pressure molded product disclosed in Non-Patent Document 1, there is room for improvement in the manufacturing method such as the pulp fibrillation step, the dry microfibrillated lignocellulosic fiber manufacturing process, and the hot-press molding conditions.

Further, it was found from the test results of the present inventors that there is room for improvement in the strength of the thermal pressure molded body disclosed in Non-Patent Document 2.

Further, in the hot-pressed molded product disclosed in Patent Document 1, there is room for improvement in the chemical modifying group, the chemical modification method, and the strength characteristics of the hot-pressed molded body of the ligno pulp or the fibrillated ligno pulp.

On the other hand, regarding the chemical modification of cellulose and pulp, in order to improve the fibrillation property of cellulose and the affinity / mixing property between cellulose and resin in the production of fiber-reinforced resin composite containing microfibrillated cellulose and resin. , Various chemically modified celluloses, lignocellulose fibers and techniques for producing them have been studied and published.

In Patent Document 2 of the present inventors, the plant fiber is esterified with an alkanoyl chloride such as octanoyl chloride, or half-esterified with an alkyl or alkenyl succinic acid anhydride and then microfibrillated to form a chemically modified microfibril. A method for producing an ester fiber and a chemically modified microfibrillated ester fiber produced by this method are disclosed.

Patent Document 3 of the present inventors discloses a resin composition containing microfibrillated plant fibers chemically modified with an alkyl or alkenyl succinic anhydride.

According to Patent Document 4 of the present inventors, a resin composition containing microfibrillated plant fibers is produced from the chemically modified fibers by modifying the plant fibers with an alkyl or alkenyl succinic anhydride in a swellable liquid. The method is disclosed.

In Patent Document 5, a part of the hydroxyl group of cellulose is half-esterified with polybasic acid anhydride, a carboxy group is introduced, and the half-esterified cellulose is made into fine fibers to form a CNF into which a carboxy group is introduced. The method of manufacture is disclosed.

Patent Document 6 of the present inventors discloses a resin composition containing CNF and a resin in which a part of the hydroxyl group of CNF is modified with a substituent having a carboxy group, and a method for producing the same.

Patent Document 7 discloses a surface-acylated cellulose fiber or a surface-acylated lignocellulosic having an acyl group substitution degree of 0.01 to 0.5, and a compounding material for plastics containing the same.

Patent Document 8 discloses fine cellulose fibers modified with a carboxymethyl group.

However, the chemically modified plant fibers, chemically modified celluloses, chemically modified lignocelluloses and their fibrillated fibers (nano-sized fibers) described in Patent Documents 2 to 8 exhibit plasticity when compressed under heating, and these It is not disclosed in Patent Documents 2 to 8 that a hot pressure molded product can be obtained by hot pressure processing.

High-strength nanocomposite based on fibrillated chemi -thermomechanical pulp, Kentaro Abe, Fumiaki Nakatsubo, Hiroyuki Yano, Composites Science and Technology 69 (2009) 2434-2437 Creation of thermoplastic nanocomposites using tree cell wall nanostructures, Yuta Watanabe, Hiromasa Ando, Kentaro Abe, Fumiaki Nakatsubo, Hiroyuki Yano, Proceedings of the Japan Wood Society Conference Vol.64th Page.NO.Z14-01-1100 , (2014.03.03)

Japanese Unexamined Patent Publication No. 2016-169382 Japanese Unexamined Patent Publication No. 2011-213754 (Patent No. 5540176) Japanese Unexamined Patent Publication No. 2012-214563 (Patent No. 5757765) Republished patent WO2013 / 133093 (Patent No. 5494435) Japanese Unexamined Patent Publication No. 2009-293167 Japanese Unexamined Patent Publication No. 2012-229350 (Patent No. 5757779) Japanese Unexamined Patent Publication No. 9-221501 Japanese Unexamined Patent Publication No. 10-251301

The present inventors have conducted various studies in order to produce a heat-press molded product of chemically modified lignocellulosic (also referred to as chemically modified lignocellulosic), which is easy to manufacture and has excellent physical properties such as strength characteristics. ..

An object of the present invention is to provide a heat-press molded product of chemically modified lignocellulosic, which can be obtained by an easy method and has excellent physical characteristics, and a method for producing the same.

In order to solve the above problems, the present inventors have conducted various studies on the fiber diameter of the lignocellulosic fiber to be chemically modified, the type of the chemically modifying group, and the thermal pressure processing method of the chemically modified lignocellulosic fiber.

As a result, it was found that the lignocellulosic fiber modified with a specific chemically modifying group exhibits thermoplasticity even with a small degree of modification. Then, they have found that by hot-pressing the lignocellulosic fibers, a hot-pressure molded body having high strength characteristics and a low coefficient of linear thermal expansion can be easily obtained, and the present invention has been completed.

Thermal pressure molding refers to molding into a desired shape through heating and pressurizing steps.

The hot-pressure molded product according to the present invention can be obtained by holding chemically modified lignocellulosic under pressure under heating. Thermal pressure processing conditions are usually 100 ° C or higher and 1 kPa or higher. If the temperature is too low or the pressure is too low, there may be inconvenience that the matrix components are not sufficiently plasticized and the desired shape cannot be obtained.

The density of the thermal pressure molded product according to the present invention is usually about 1.1 to 1.5 g / cm ³ . Conventionally, the heating step in the known papermaking process is at most about 120 ° C., and the density of the obtained paper is at most about 1.0 g / cm ³ although the pressure in the pressurizing step is unknown. Therefore, it can be seen that in the known papermaking process, adhesion due to plasticization of the constituent components (vegetable fiber) does not occur.

The present invention relates to a thermal pressure molded product and a method for producing the same.

More specifically, the present invention relates to a heat-press molded body of chemically modified lignocellulosic having the characteristics of (a) and (b) described later, and a method for producing the same.

Definitions of Terms In the present specification, the following terms have the following meanings, respectively.

Lignocellulosic (or LC): means a substance in which lignin and cellulose are bound, or / or a mixture of lignin and cellulose, which is present in plants regardless of the amount of lignin.

-Pulp: A separated plant fiber contained in plants such as wood, bamboo, and rice straw, which contains cellulose and / and lignocellulosic.

Lignocellulosic (or LP): means pulp containing lignocellulosic.

Item 1.
A heat-press molded product of chemically modified lignocellulosic
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4.

Item 2.
The hot-press molded product according to Item 1 above.
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-1) A part of the hydroxyl group existing in the lignocellulosic is the following formula (1) :.

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4.

Item 3.
The hot-press molded product according to Item 1 above.
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n is an integer of 1.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.3.

Item 4.
The heat-pressure molded product according to any one of Items 1 to 3 above.
The content of the lignin component of the chemically modified lignocellulosic is 2 to 40% by mass.
Thermal pressure molded body.

Item 5.
Item 4. The heat-pressure molded product according to any one of Items 1 to 4, further containing a thermoplastic resin.

Item 6.
A method for producing a heat-press molded product of chemically modified lignocellulosic.
Including the step of compressing a fiber aggregate composed of chemically modified lignocellulosic fibers under heating.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4.

Item 7.
Item 6 is the method for manufacturing a heat-press molded product according to Item 6.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-1) A part of the hydroxyl group existing in the lignocellulosic is the following formula (1) :.

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4.

Item 8.
Item 6 is the method for manufacturing a heat-press molded product according to Item 6.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n is an integer of 1.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.3.

Item 9.
Item 6. The method for manufacturing a hot-pressure molded product according to any one of Items 6 to 8.
The average fiber diameter of the chemically modified lignocellulosic fiber is 20 nm to 50 μm.
A method for manufacturing a thermal pressure molded product.

Item 10.
Item 6. The method for manufacturing a hot-pressure molded product according to any one of Items 6 to 9.
The content of the lignin component of the chemically modified lignocellulosic fiber is 2 to 40% by mass.
A method for manufacturing a thermal pressure molded product.

Item 11.
Item 6. The method for manufacturing a hot-pressure molded product according to any one of Items 6 to 10.
A method for producing a heat-press molded body, wherein the fiber aggregate made of the chemically modified lignocellulosic fiber is heated at a temperature of 160 to 240 ° C. and a compression pressure of 30 to 100 MPa.

Item 12.
The method for manufacturing a thermal pressure molded product according to any one of claims 6 to 11.
A method for producing a heat-press molded product, which uses a fiber aggregate containing a thermoplastic resin as a fiber aggregate composed of chemically modified lignocellulosic fibers.

Item 13.
A method for producing a heat-press molded product of chemically modified lignocellulosic.
A method for manufacturing a hot-pressed molded product, which comprises the following first and second steps:
(1) First step :
(A-1) For lignocellulosic fiber, the following formula (3):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
The following formula (1)::

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
By half-esterifying with a carboxy group-containing acyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the lignocellulosic to be half-esterified to 0.01 to 0.4.
Or,
(A-2) For lignocellulosic fiber, the following formula (4):
X- (CH ₂ ) _n -COOH ・ ・ ・ ・ (4)
(In the formula, n represents an integer of 1 to 3. X represents a halogen atom selected from the group consisting of Cl, Br and I.)
By reacting the halogenoalkylcarboxylic acid represented by the above formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
By etherifying with a carboxyalkyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the etherified lignocellulosic to 0.01 to 0.4.
(2) Second step :
A step of compressing a fiber aggregate made of chemically modified lignocellulosic fibers obtained in the first step under heating.

Item 14.
Item 32, the method for manufacturing a heat-press molded product according to Item 13.
A method for producing a heat-press molded body, wherein the fiber aggregate made of the chemically modified lignocellulosic fiber is heated at a temperature of 160 to 240 ° C. and a compression pressure of 30 to 100 MPa.

The structure of the heat-pressure molded product of the present invention is (i) a matrix of lignin contained in the chemically modified lignocellulose fiber as a raw material, chemically modified lignin, hemicellulose, and chemically modified hemicellulose (ii). ) Cellulose nanofibers (CNF) and chemically modified cellulose are used as fillers, and can be said to be nanocomposites.

Therefore, the heat-press molded body of the present invention is lightweight, has high strength, and has a low coefficient of linear thermal expansion, similar to plant fibers.

The heat-pressure molded article of the present invention is used for interiors of transport machines (for example, automobiles, ships, aircraft) that are lightweight and require mechanical strength (for example, high tensile strength and elastic modulus) in addition to the fields of application of fiber reinforced plastics. It can be preferably used as a housing for exterior materials and electrical appliances.

Since the heat-pressure molded product of the present invention is lighter than metals, it is effective in reducing fuel consumption when used in a transport aircraft, for example. As a result, the heat-pressure molded product of the present invention reduces exhaust gas and is also useful for environmental conservation.

The heat-press molded product of the present invention can be easily produced by a simple operation of compressing a chemically modified lignocellulosic fiber aggregate under heating. Therefore, the heat-pressure molded body of the present invention also has an advantage that it can be manufactured with energy saving as compared with the conventional material (carbon fiber reinforced resin, glass fiber reinforced resin, or metal molded body).

(1) Thermal pressure molded product of chemically modified lignocellulosic
Thermal pressure molded product (Invention 1)
In the heat-press molded product of chemically modified lignocellulosic, the chemically modified lignocellulosic has the following properties (a) and (b):
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4.

In other words, the thermal pressure molded product of the present invention includes the following aspects (1) or (2).

Aspect (1)
In the heat-press molded product of chemically modified lignocellulosic, the chemically modified lignocellulosic has the following properties (a) and (b):
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.

The degree of substitution is preferably 0.1 to 0.4.

Aspect (2)
In the heat-press molded product of chemically modified lignocellulosic, the chemically modified lignocellulosic has the following properties (a) and (b):
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4.

The degree of substitution is preferably 0.01 to 0.3.

Raw Material for Chemically Modified Lignocellulosic Fiber (Invention 9)
A method for producing a chemically modified lignocellulosic fiber used for producing a thermostatically formed body will be described.

Ligno pulp can be used as a raw material for chemically modified lignocellulosic fibers.

Ligno pulp is a raw material derived from plant-derived materials contained in coniferous or broad-leaved wood such as sitka spruce, pine, cedar, hinoki, eucalyptus, and acacia, bamboo, hemp, jute, kenaf, bagasse, straw, and beet squeezed residue. Can be used as ligno pulp obtained by treating with a mechanical pulping method, a chemical pulping method, or a combination of a mechanical pulping method and a chemical pulping method. As such pulp, various kraft pulps containing lignin (coniferous unbleached kraft pulp (NUKP), coniferous oxygen-exposed unbleached kraft pulp (NOKP), coniferous bleached kraft pulp (NBKP) are preferable. Mechanical pulp (MP) such as (GP), refiner GP (RGP), thermomechanical pulp (TMP), and chemithermomechanical pulp (CTMP) is preferable because it contains lignin.

Lignocellulosic derived from vegetable raw materials contains lignocellulosic, and is mainly composed of cellulose, hemicellulose, and lignin.

In the present invention, pulp in which lignin is not completely removed and contains even a small amount of lignin can be used as ligno pulp. Therefore, the pulp containing lignin, which can also detect the pulp obtained by the above-mentioned various pulping methods, is referred to as ligno pulp in the present specification. Pulp derived from used paper such as deinked used paper, corrugated cardboard, magazines, copy paper, etc., which contains ligno pulp can also be used in the present invention as ligno pulp.

The amount of lignin contained can be quantified by the Clarson method. In the present invention, it is preferable to use ligno pulp containing about 2 to 40% by mass of lignin. It is more preferable to use ligno pulp having a lignin content of about 2 to 35% by mass, particularly preferably about 2 to 30% by mass.

In addition to the fact that the lignin and hemicellulose contained in the ligno pulp function as a matrix of the heat-press molded product of the present invention, the yield from the raw material thereof is large, the number of steps is small, and the number of chemical agents required for the production thereof is small. Therefore, it can be used in an advantageous manner in the present invention.

The heat-pressure molded product of the present invention is produced by hot-pressing a chemically modified lignocellulose fiber, and this chemically modified lignocellulose fiber chemically modifies the lignocellulose fiber obtained by defibrating the ligno pulp. Can be manufactured by.

The average fiber diameter of the chemically modified lignocellulosic fiber is preferably about 20 nm to 50 μm.

If the fiber diameter is too small, the solvent retention of the fiber becomes too high, which may cause inconveniences such as difficulty in removing the solvent. Further, if the fiber diameter is too large, the fibers may not be sufficiently adhered to each other during thermal pressure molding, and excellent strength may not be exhibited. For this reason, the average fiber diameter of the chemically modified lignocellulosic fiber is more preferably about 500 nm to 30 μm.

Half ester of lignocellulosic fiber (Aspect (1))
As described in the above aspect (1), in the heat-press molded product of the chemically modified lignocellulosic, the chemically modified lignocellulosic fiber as the raw material has a part of the hydroxyl groups present in the lignocellulosic according to the above formula (1). It is half-esterified with the represented carboxy group-containing acyl group.

This is also referred to as "the half-esterified lignocellulosic fiber".

The half-esterified lignocellulosic fiber is a lignocellulosic fiber according to the following formula (3):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Succinic anhydride represented by (hereinafter, these acid anhydrides may be referred to as "acid anhydride of formula (3)". ], And a part of the hydroxyl group existing in the lignocellulose is half-esterified with the carboxy group-containing acyl group represented by the formula (1) in the lignocellulose to be half-esterified. It can be manufactured by setting the degree of substitution of the hydrogen atom of the hydroxyl group of the above to 0.01 to 0.4.

The chemical modification of the lignocellulose fiber with the acid anhydride of the formula (3) is carried out by heating the acid anhydride of the formula (3) in the presence of a base and reacting the lignocellulose fiber dispersed in an organic solvent in the lignocellulose. Half-esterify some of the hydroxyl groups present in.

Here, in the half ester, one of the two carbonyl groups present in the acid anhydride of the formula (3) forms an ester bond with the hydroxyl group in lignocellulose, and the other carbonyl group is a hydroxycarbonyl group. It refers to the ester in the state of being in a state of being.

Examples of the alkenyl succinic anhydride belonging to the acid anhydride of the formula (3) include a compound having a skeleton derived from an olefin having 4 to 20 carbon atoms and a maleic anhydride skeleton.

Examples of these compounds include pentenyl succinic anhydride, hexenyl succinic anhydride, octenyl succinic acid anhydride, decenyl succinic acid anhydride, undecenyl succinic acid anhydride, dodecenyl succinic acid anhydride, tridecenyl succinic acid anhydride, and hexadecese. Alkenyl succinic anhydrides such as nyl succinic anhydride and octadecenyl succinic anhydride can be preferably used.

As the alkenyl succinic anhydride, each compound may be used alone, or two or more kinds may be used in combination.

In the present specification, an alkenyl succinic anhydride having an olefin chain having a specific carbon number may be expressed by combining the abbreviation (ASA) of the alkenyl succinic anhydride and the carbon number of the olefin chain.

For example, an alkenyl succinic anhydride (hexadecenyl succinic anhydride) having an olefin chain having 16 carbon atoms may be referred to as "ASA-C16". In addition, the ASA used in the present invention may be described by a product name or a product code number. For example, AS1533 (manufactured by Seiko PMC Corporation), TNS135 (manufactured by Seiko PMC Corporation), Ricacid DDSA (tetrapropenyl succinic anhydride, manufactured by Shin Nihon Rikagaku Co., Ltd.) and the like can be preferably used.

As the alkyl succinic anhydride, the unsaturated bond of the alkenyl group of the alkenyl succinic anhydride represented by the above formula (2) is reduced by hydrogenation (that is, the alkenyl group is converted into an alkyl group. Acid anhydride) can be used.

As these compounds, alkyl succinic anhydrides such as octyl succinic acid anhydride, dodecyl succinic acid anhydride, hexadecyl succinic acid anhydride, and octadecyl succinic acid anhydride can be preferably used.

As the alkylsuccinic anhydride, each compound may be used alone, or two or more kinds may be used in combination. Further, an alkyl succinic anhydride and an alkenyl succinic anhydride can be used in combination.

The amount of the Anhydride required for the chemical modification of the lignocellulosic fiber is preferably about 0.004 to 0.18 times the number of moles of the hydroxyl group contained in the lignocellulosic fiber (absolute dry amount), more preferably 0.04 to 0.18 times. A molar amount is preferable.

The reaction between the lignocellulosic fiber and the acid anhydride of the formula (3) is preferably carried out in an organic solvent. The ligno pulp fiber can be dried, suspended in an organic solvent and reacted with the acid anhydride of the formula (3).

Ligno pulp fibers are usually in a water-containing state (aqueous dispersion). By adding an organic solvent to the water-containing ligno pulp, filtering the ligno pulp, and then dispersing and filtering the ligno pulp again (solvent replacement operation), the ligno pulp can be dispersed in the organic solvent and the reaction can be carried out.

The organic solvent used is preferably a water-soluble aprotic solvent that can swell the ligno pulp without reacting with the acid anhydride of the formula (3). Examples of those satisfying this condition include N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), and tetrahydrofuran (THF).

In the reaction between the lignocellulosic fiber and the acid anhydride of the formula (3), it is preferable to carry out the reaction in the presence of a base in order to accelerate the reaction. As the base, amines such as pyridine and dimethylaniline, alkali metal salts of acetic acid such as potassium acetate and sodium acetate, and alkali metal carbonates such as lithium carbonate, potassium carbonate and sodium carbonate can be preferably used.

The reaction temperature is preferably about 20 to 150 ° C, more preferably about 30 to 120 ° C, still more preferably about 40 to 100 ° C, although it depends on the boiling point of the solvent used.

The reaction time also depends on the type of acid anhydride of the formula (3). The degree of half-esterification by taking a portion of the lignocellulosic fiber during the reaction and measuring this infrared (IR) absorption spectrum to trace the IR absorption peak based on the carbonyl expansion and contraction vibration of the half-ester generated by the reaction. It can be adjusted while checking (replacement degree).

Degree of Substitution of Half Esterification The degree of hearth esterification of the hydroxyl groups present in the ligno pulp fiber (the degree of substitution of hearth esterification will be described.

The half ester refers to an ester in which one carboxy group of the dicarboxylic acid forms an ester bond with an alcoholic hydroxyl group and one carboxy group does not have an ester bond (that is, a free carboxylic acid state). Therefore, half-esterification of lignocellulosic means that one carboxy group of the hydroxyl group and the dicarboxylic acid in lignocellulosic forms an ester bond, and the other carboxy group is in a free state.

In the half-esterification reaction with the acid anhydride of the formula (3), the hydrogen atom of the hydroxyl group in the lignocellulose fiber is replaced with one of the two carbonyl groups present in the acid anhydride of the formula (3) to esterify. Bonds are formed and half esters are formed.

The half-ester of lignocellulose is in a chemically bonded state in which the hydrogen atom of the hydroxyl group existing in lignocellulose is replaced by the carbonyl group in the carboxy group. Substitution of the hydrogen atom of the hydroxyl group inside ".

The degree of this substitution (DS) is referred to as "degree of substitution of hydrogen atom of hydroxyl group in lignocellulose by half-esterification (DS)", "degree of half-esterification (DS)" or "half-esterified DS", and ligno. It is defined as the average number of esterified hydroxyl groups in a repeating unit of cellulose.

The repeating unit of pure cellulose is the glucopyranose residue (glucose residue), which has three hydroxyl groups. Therefore, the upper limit of half-esterified DS of pure cellulose is 3.

On the other hand, lignocellulosic contains hemicellulose and lignin together with cellulose. The number of hydroxyl groups of the xylose residue in xylan and the galactose residue in arabinogalactan contained in hemicellulose is 2, and the number of hydroxyl groups of the lignin residue is also 2, and the number of these hydroxyl groups is smaller than 3. Therefore, the number of hydroxyl groups in the average repeating unit of lignocellulosic is less than 3, and its upper limit is less than 3.

From this, the upper limit of the half-esterified DS of the lignocellulosic fiber is smaller than 3. The upper limit of the half-esterified DS is about 2.7 to 2.8 depending on the contents of hemicellulose and lignin contained in the lignocellulosic fiber.

The half-esterified DS of the chemically modified lignocellulosic fiber is preferably controlled to 0.01 to 0.4, more preferably 0.1 to 0.4. That is, in the chemically modified lignocellulose fiber as a raw material of the heat-press molded product, a part of the hydroxyl groups existing in the lignocellulose is half-esterified with the carboxy group-containing acyl group represented by the above formula (1). The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulose is preferably 0.1 to 0.4.

If the half-esterified DS is less than 0.01, the plasticity tends to be insufficient during thermal pressure processing and molding tends to be difficult. When this half-esterified DS exceeds 0.4, the viscosity of the reaction mixture increases and becomes a gel state, and it tends to be difficult to separate and wash the chemically modified lignocellulosic fibers in the reaction mixture.

Chemical modification of lignocellulosic fibers with carboxyalkyl groups (Aspect (2))
As described in the above aspect (2), in the heat-press molded product of the chemically modified lignocellulosic, the chemically modified lignocellulosic fiber as the raw material has a part of the hydroxyl groups present in the lignocellulosic according to the above formula (2). It is etherified with the represented carboxylalkyl group.

The carboxyalkyl group represented by the above formula (2) is also referred to as "the Carboxyalkyl Group".

The lignocellulosic fiber (chemically modified lignocellulosic fiber) etherified with the Carboxyalkyl group is converted into a lignocellulosic fiber according to the following formula (4):
X- (CH ₂ ) _n -COOH ・ ・ ・ ・ (4)
(In the formula, n represents an integer of 1 to 3. X represents a halogen atom selected from the group consisting of Cl, Br and I.)
By reacting a halogenoalkylcarboxylic acid represented by (2), a part of the hydroxyl groups present in the lignocellulosic acid is represented by (2). By etherifying with an alkyl group, the degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic acid is set to 0.01 to 0.4, whereby the raw material (chemically modified lignocellulosic fiber) of the heat-pressure molded product of the present invention is produced. can do.

In the chemically modified lignocellulosic fiber, a halogenoalkylcarboxylic acid or a salt thereof is heated and reacted in the presence of a base to form an ether bond with the oxygen atom of the hydroxyl group present in the lignocellulosic acid and the carboxyalkyl group. The formation of this ether bond is referred to as "the present etherification" in the present specification, and this reaction is referred to as "the present etherification reaction".

As the halogenoalkylcarboxylic acid of the present invention, those in which X (halogen atom) is a chlorine atom or a bromine atom are preferable.

As the salt of the halogenoalkylcarboxylic acid of the present invention, an alkali metal salt is preferable.

Preferred halogenoalkylcarboxylic acids and salts thereof include chloroacetic acid, bromoacetic acid, 3-chloropropionic acid, 3-bromopropionic acid, 4-chlorobutyric acid and 4-bromobutyric acid, and their sodium and potassium salts. A lithium salt can be exemplified.

As the halogenoalkylcarboxylic acid and its salt, each compound may be used alone, or two or more kinds thereof may be used in combination.

The amount of the Harogenoalkylcarboxylic acid or a salt thereof used in the etherification reaction is usually preferably 0.01 to 0.45 times the number of moles of the hydroxyl group contained in the lignocellulosic fiber (absolute dry amount). More preferably, 0.01 to 0.35 times mol is preferable.

The etherification reaction can be carried out in water or in a mixed solvent of water and a water-soluble organic solvent (for example, alcohol). The lignocellulosic fibers to be subjected to this reaction are usually produced as an aqueous suspension. Lignocellulosic fiber can be mixed with a base and the present halogenoalkylcarboxylic acid and / or a salt thereof and heated.

Bases used in this reaction include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, etc. A carbonate, a hydrogen carbonate, or the like can be preferably used.

The amount of the base used is usually preferably about 1 to 5 equivalents, more preferably about 1 to 4 equivalents, relative to the Halogenoalkylcarboxylic acid of the present case.

The etherification reaction is preferably carried out at 30 to 90 ° C. with stirring.

This reaction time is usually about 0.5 to 5 hours depending on the type of the halogenoalkylcarboxylic acid or a salt thereof and the amount used thereof.

A portion of the lignocellulosic fiber during the reaction is sampled and this infrared (IR) absorption spectrum is measured to trace the IR absorption peak based on the carbonyl expansion and contraction vibration of the carboxy group of the carboxy group of the carboxyalkyl ether generated by the reaction. It can be adjusted while checking the degree of conversion (degree of substitution).

Degree of Substitution of Etherealization The degree to which the hydroxyl group present in the ligno pulp fiber is etherified by the halogenoalkylcarboxylic acid will be described.

In the etherification reaction of the present case, the hydrogen atom of the hydroxyl group in the lignocellulosic fiber is substituted with the carboxyalkyl group of the present case to form an ether bond. In the present specification, this is referred to as "degree of substitution of hydrogen atom of hydroxyl group in lignocellulosic by etherification (DS)" or "degree of etherification substitution: etherified DS". This indicates the degree to which the hydroxyl group present in the ligno pulp fiber is etherified by the halogenoalkylcarboxylic acid of the present case.

This degree of etherification substitution (etherified DS) is defined as the average number of hydroxyl groups in the repeating unit of lignocellulosic etherified.

The repeating unit of pure cellulose is the glucopyranose residue (glucose residue), which has three hydroxyl groups. Therefore, the upper limit of DS for etherification of pure cellulose is 3.

On the other hand, lignocellulosic contains hemicellulose and lignin together with cellulose. The number of hydroxyl groups of the xylose residue in xylan and the galactose residue in arabinogalactan contained in hemicellulose is 2, and the number of hydroxyl groups of the lignin residue is also 2, and the number of these hydroxyl groups is smaller than 3. Therefore, the number of hydroxyl groups in the average repeating unit of lignocellulosic is less than 3, and its upper limit is less than 3.

From this, the upper limit of the etherified DS of the lignocellulosic fiber is smaller than 3 as in the above-mentioned half-esterified DS, and the upper limit depends on the content of hemicellulose and lignin contained in the lignocellulosic fiber. , 2.7-2.8.

The etherified DS of the chemically modified lignocellulosic fiber is preferably controlled to 0.01 to 0.4, more preferably 0.01 to 0.3, and further preferably 0.01 to 0.2. That is, in the chemically modified lignocellulosic fiber of the heat-press molded product, a part of the hydroxyl group existing in the lignocellulosic is etherified with the carboxyalkyl group represented by the above formula (2), and the etherified. The degree of substitution of the hydrogen atom of the hydroxyl group in lignocellulosic is preferably 0.01 to 0.4.

If the etherified DS is less than 0.01, the plasticity tends to be insufficient during thermal pressure processing and molding tends to be difficult. When the etherified DS exceeds 0.4, the viscosity of the reaction mixture increases and becomes a gel state, and it tends to be difficult to separate and wash the chemically modified lignocellulosic fibers in the reaction mixture.

After the half-esterification reaction of the lignocellulose fiber with the acid anhydride of the above formula (3) or the etherification reaction with the halogenoalkylcarboxylic acid of the above formula (4), the reaction mixture is neutralized. Then, the chemically repaired lignocellulose fibers are separated and washed by a deliquescent device such as filtration and centrifugation.

Water and, if necessary, a solvent such as alcohol can be used for cleaning.

After cleaning, the chemically repaired lignocellulosic fibers are subjected to the next thermal pressure step.

Thermal pressure molded body (Invention 2 and 3)
The heat-pressure molded product of the present invention is preferably the following aspect (1) or (2).

Aspect (1)
In the heat-press molded product of chemically modified lignocellulosic, the chemically modified lignocellulosic fibers have the following properties (a) and (b):
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4.

Aspect (2)
In the heat-press molded product of chemically modified lignocellulosic, the chemically modified lignocellulosic fibers have the following properties (a) and (b):
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n is an integer of 1.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.3.

The carboxyalkyl group represented by the formula (2) is preferably a carboxymethyl group (-CH ₂ -COOH).

Lignin component content (Inventions 4 and 10)
In the heat-pressure molded product of the present invention, the content of the lignin component of the chemically modified lignocellulosic fiber is preferably about 2 to 40% by mass. The content of the lignin component of the chemically modified lignocellulosic fiber is more preferably about 2 to 35% by mass, further preferably about 2 to 30% by mass.

The content of the lignin component means the mass% of the lignin component in the mass (mass converted to lignocellulosic) obtained by subtracting the mass of the chemically modified group from the chemically modified lignocellulosic. Lignin usually does not fall off from the raw material lignocellulosic due to chemical modification, or even if it falls off, it is in a trace amount. The lignin component content (% by mass) corresponds to the lignin content mass% contained in the lignocellulosic used for this chemical modification.

The thermal pressure molded product of the present invention also includes a combination of the above aspects (1) and (2). That is, a mixture of lignocellulosic in which a part of the hydroxyl group present in lignocellulosic with the acyl group of the formula (1) is half-esterified and lignocellulosic etherified with the carboxyalkyl group of the formula (2). The hot-pressed molded product made of the above is included in the hot-pressed molded product of the chemically modified lignocellulosic of the present invention.

(2) Method for manufacturing a heat-pressure molded product of chemically modified lignocellulosic
Method for manufacturing a heat-press molded product (invention 6 to 8)
The method for producing a thermally compacted body of chemically modified lignocellulosic of the present invention includes a step of compressing a fiber aggregate composed of chemically modified lignocellulosic fibers under heating, and the chemically modified lignocellulosic is described in the following (a) and (b). ) Has the characteristics:
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4.

The carboxyalkyl group represented by the formula (2) is preferably a carboxymethyl group (-CH ₂ -COOH).

In the method for producing a thermally compacted body, in the chemically modified lignocellulosic fiber, a part of the hydroxyl groups existing in the lignocellulosic is half-esterified with the carboxy group-containing acyl group represented by the formula (1). It is preferable that the degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4.

In the method for producing a heat-press molded product, in the chemically modified lignocellulosic fiber, a part of the hydroxyl groups present in the lignocellulosic is etherified with a carboxyalkyl group represented by the formula (2), and the ether is used. It is preferable that the degree of substitution of the hydrogen atom of the hydroxyl group in the converted lignocellulosic is 0.01 to 0.3.

It is preferred that the chemically modified lignocellulosic fibers or fiber aggregates, if necessary, be washed and / and dispersed and then compression molded under heating. A uniform molding surface can be obtained prior to molding.

As one method of pulverization, for example, ethanol or the like, preferably a solvent having a boiling point of 100 ° C. or lower is added to a fiber or a fiber aggregate containing chemically modified lignocellulosic, and the mixture is stirred with a mixer or the like to obtain a solid content (chemical modification). Fiber lignocellulosic fiber) It is preferable to obtain a suspension having an adjusted concentration. Then, it is preferable to remove the solvent from this suspension by means such as filtration and dry it to obtain a material for molding (fiber aggregate of chemically modified lignocellulosic fibers).

Fiber aggregates of chemically modified lignocellulosic fibers tend to shrink due to drying and the pressurized surface tends to bend. As described above, when the material for molding (fiber aggregate of chemically modified lignocellulose fibers) is prepared by filtration, the filtration surface having the same shape as the bottom surface of the mold (molding mold) of the target molded product. It is preferable to prepare a material for molding by filtering it with a filter having the above, and then put it in a mold for hot pressure molding. This makes it possible to produce a molded product having a uniform surface and excellent strength characteristics.

Heating temperature and compression pressure (Invention 11)
When producing a thermally compacted body of chemically modified lignocellulosic, the temperature of thermal pressure processing is preferably about 160 to 240 ° C. in order to avoid thermal decomposition of the chemically modified lignocellulosic fibers.

The compression pressure during hot pressure processing is preferably set to 30 MPa to 100 MPa.

In the method for producing a thermally compacted body of chemically modified lignocellulosic of the present invention, a fiber aggregate composed of the chemically modified lignocellulosic fibers is compressed at a pressure of 30 MPa to 100 MPa while heating at a temperature of 160 to 240 ° C. Is preferable. Chemically modified lignocellulosic exhibits plasticity and can avoid thermal decomposition. By processing the fiber aggregates of chemically modified lignocellulosic fibers at these temperatures and pressures, a thermopressure molded body having excellent strength characteristics can be produced.

Method for manufacturing a heat-press molded product including the first step and the second step (inventions 13 and 14)
The method for producing a thermostatically molded article of the present invention will be described in order from the step of chemically modifying the lignocellulose fiber. It is preferable to include.

(1) First step :
(A-1) For lignocellulosic fiber, the following formula (3):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
The following formula (1)::

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
By half-esterifying with a carboxy group-containing acyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the lignocellulosic to be half-esterified to 0.01 to 0.4.
Or,
(A-2) For lignocellulosic fiber, the following formula (4):
X- (CH ₂ ) _n -COOH ・ ・ ・ ・ (4)
(In the formula, n represents an integer of 1 to 3. X represents a halogen atom selected from the group consisting of Cl, Br and I.)
By reacting the halogenoalkylcarboxylic acid represented by the above formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
By etherifying with a carboxyalkyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the etherified lignocellulosic to 0.01 to 0.4.
(2) Second step :
A step of compressing a fiber aggregate made of chemically modified lignocellulosic fibers obtained in the first step under heating.

The carboxyalkyl group represented by the formula (2) is preferably a carboxymethyl group (-CH ₂ -COOH).

In the method for producing a thermally compacted body, it is preferable that the fiber aggregate made of the chemically modified lignocellulosic fiber is heated at a temperature of 160 to 240 ° C. and compressed at a pressure of 30 MPa to 100 MPa.

Among the chemically modified lignocellulosic heat-press molded products of the present invention, as one embodiment, lignocellulosic in which a part of the hydroxyl groups present in lignocellulosic with the acyl group of the above formula (1) is half-esterified and the above-mentioned formula ( There is a thermal pressure molded product composed of a mixture with lignocellulosic etherified with the carboxyalkyl group of 2). In this embodiment, the lignocellulosic fiber in which a part of the hydroxyl group present in the lignocellulosic is half-esterified with the acyl group of the formula (1) obtained in the first step and the carboxyalkyl group of the formula (2) are used. It can be produced by mixing with etherified lignocellulosic fibers and compressing the mixed fiber aggregate under heating.

(3) Thermal pressure molded product of chemically modified lignocellulosic
Thermopress molded product further containing a thermoplastic resin (Inventions 5 and 12)
In the heat-press molded product of the present invention, it is preferable that the chemically modified lignocellulosic fiber further contains a thermoplastic resin.

In the method for producing a thermally compacted body of the present invention, it is preferable to use a fiber aggregate further containing a thermoplastic resin as the fiber aggregate composed of the chemically modified lignocellulosic fiber.

The thermal pressure molded product of the present invention may appropriately contain a resin as long as the effects of the present invention are not impaired, and it is preferable to use a thermoplastic resin among the resins.

As a thermoplastic resin, polyamide (nylon resin, PA), polyacetal (POM), polyolefin resin [polypropylene (PP), maleic anhydride-modified PP (maleic anhydride-modified PP), from the viewpoint of excellent mechanical properties, heat resistance, surface smoothness and appearance. MAPP), polyethylene (PE), etc.], polyester, polycarbonate, polylactic acid, polyester, polylactic acid and polyester copolymer resin, PBS resin (polybutylene succinate), polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin) Etc. are preferred.

In addition, polyvinyl chloride, polyvinylidene chloride, fluororesin, (meth) acrylic resin, polyphenylene oxide, (thermoplastic) polyurethane, vinyl ether resin, polysulfone resin, cellulose resin (for example, triacetylated cellulose, diacetylated cellulose). Etc. can also be preferably used.

As polyamide (amide resin), nylon 66 (polyhexamethylene adipamide, polyamide 66, PA66), nylon 6 (ε-caprolactam ring-opening polymer, polyamide 6, PA6), nylon 11 (undecanlactam) are opened. Polyamide, Polyamide 11, PA11), Nylon 12 (Polyamide, Polyamide 12, PA12), Nylon 46 (Polyamide 46, PA46), Nylon 610 (Polyamide 610, PA610), Nylon 612 It is preferable to use an aliphatic amide resin such as (polyamide 612, PA612). As the polyamide resin, it is also preferable to use an aromatic diamine such as phenylenediamine and an aromatic polyamide composed of an aromatic dicarboxylic acid such as terephthaloyl chloride or isophthaloyl chloride or a derivative thereof.

These resins may be used alone or as a mixed resin of two or more kinds.

Since the polyamide resin (PA) has a highly polar amide bond in its molecular structure, it has an advantage of having a high affinity with a cellulosic material. As the polyamide resin (PA), it is preferable to use PA6, PA66, PA11, PA12, etc., a polyamide copolymer resin, or the like.

As the polyacetal (POM), polymers and copolymers such as trioxane, formaldehyde, and ethylene oxide can be preferably used.

As the polyolefin resin, it is preferable to use polypropylene (PP), polyethylene (PE, particularly high-density polyethylene: HDPE) or the like having versatility as a structural member. Further, it is preferable to use maleic anhydride-modified polypropylene (MAPP) having high compatibility with these general-purpose polyolefins.

As the polyester, aromatic polyester, aliphatic polyester, unsaturated polyester and the like can be preferably used.

As the aromatic polyester, a copolymer of diols such as ethylene glycol, propylene glycol and 1,4-butanediol and an aromatic dicarboxylic acid such as terephthalic acid can be preferably used.

Examples of the aliphatic polyester include polymers and copolymers of diols and aliphatic dicarboxylic acids such as succinic acid and valeric acid, homopolymers or copolymers of hydroxycarboxylic acids such as glycolic acid and lactic acid, and diols. An aliphatic dicarboxylic acid and a copolymer of the hydroxycarboxylic acid can be preferably used.

As the unsaturated polyester, a copolymer of diols, an unsaturated dicarboxylic acid such as maleic anhydride, and, if necessary, a vinyl monomer such as styrene can be preferably used.

When the thermoplastic resin of the present invention contains the thermoplastic resin, the chemically modified lignocellulose fiber as a raw material and the thermoplastic resin are mixed, and the mixture of the fiber and the thermoplastic resin is heated under the above conditions. It can be manufactured by pressure molding.

The mixture of the chemically modified lignocellulosic fiber and the thermoplastic resin can be prepared by mixing the resin with the chemically modified lignocellulosic fiber dispersed in an insoluble solvent and by separation means such as filtration and centrifugation. can.

For the mixing of the chemically modified lignocellulose fiber and the thermoplastic resin, the resin is mixed with the dispersion liquid (aqueous dispersion) of the chemically modified lignocellulose fiber after the completion of the chemical modification and collected by filtration. Lignocellulose fibers and resin mixtures can be prepared.

It is preferable to mix the resin in the form of fibers, fine powders or particles having a fine fiber diameter in order to obtain thermal pressure molding in which the chemically modified lignocellulosic and the resin are uniformly mixed.

Other Additives to Thermo-Pressure Molds The thermo-press molded products of the present invention are inorganic compounds such as zeolites, ceramics and metal powders, colorants, conductive agents and antistatic agents as long as the effects of the present invention are not impaired. , Antistatic agent and the like can be appropriately contained. By mixing these additives with a raw material for producing a thermal pressure molded product (chemically modified lignocellulosic fiber aggregate), the thermal pressure molded product of the present invention can be produced.

Salt of the hot-pressure molded product The hot-pressure molded product of the present invention has the carboxy group in the carboxy-containing acyl group represented by the above formula (1) and the above formula (2) as long as the effect of the present invention is not impaired. ) May form a salt in part or all of the carboxy group in the carboxyalkyl group-containing acyl group, and such a thermal-pressure molded product is also included in the present invention.

Examples of such salts include alkali metal salts, alkaline earth metal salts, and organic salts with amines.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The present invention is not limited to these examples.

In Examples and Comparison,% of the component content of pulp, lignocellulosic, modified lignocellulosic such as lignin, cellulose, hemicellulose, etc. indicates mass% unless otherwise specified.

Unless otherwise specified,% of the concentration of each component in the dispersion or solution indicates mass%.

In Examples and Production Examples (raw material production), "chemical modification" or "modification" may be used as an alternative term for "chemical modification" or "modification".

"Unmodified" may be used as an alternative term to "unmodified", "unmodified" or "unmodified".

1. 1. Terms / Abbreviations The following abbreviations used in Examples and Comparative Examples have the following meanings.

NCTMP: Chemical thermomechanical pulp derived from coniferous trees
NUKP: Unbleached kraft pulp from coniferous trees
CSF: Canadian standard drainage
MCA: Monochloroacetic acid

2. Raw materials used
2-1. Chemical Thermomechanical Pulp (NCTMP) Derived from Coniferous Trees
Composition (% by mass):
Lignin (Lig) 27

2-2. Unbleached kraft pulp from coniferous trees (NUKP)
Composition (% by mass):
Cellulose (Cel) 74.5,
Lignin (Lig) 9.9,
Hemicellulose 15.6 [Glucomannan (GlcMan) 7.3, Xylan (Xy) 7.4, Arabinogalactan (AraGal) 0.9 (Arabinan (Ara) 0.45, Galactan (Gal) 0.45)]

3. 3. Test method / measurement method and equipment used
(I) Lignin quantification method (Clarson method)
The glass fiber filter paper (GA55) was dried in an oven at 105 ° C. to a constant weight, allowed to cool in a desiccator, and then weighed. Lignocellulosic (about 0.2 g of sample) dried at 105 ° C. was precisely weighed and placed in a 50 mL beaker. 3 mL of 72% concentrated sulfuric acid was added, and the mixture was left in warm water at 30 ° C. for 1 hour while being appropriately crushed with a glass rod so that the contents became uniform.

Then, 84 g of distilled water was added to the contents, and the mixture was quantitatively transferred to an Erlenmeyer flask and then reacted at 120 ° C. for 1 hour in an autoclave. After allowing to cool, the contents were filtered through a glass fiber filter paper and washed with 200 mL of distilled water. It was dried and weighed in an oven at 105 ° C until it reached a constant weight.

(Ii) Quantitative method of cellulose and hemicellulose (sugar analysis)
Lignocellulosic was placed in an oven desiccator and dried at 50 ° C. for 3 hours under reduced pressure with a vacuum pump. About 30 mg of the dried sample was precisely weighed and placed in a pressure resistant test tube, and then 200 μL of fucose (0.1 g / mL) was added as an internal standard. Using a measuring pipette, 0.3 mL of 72% concentrated sulfuric acid was added, pressed with a glass rod to make it uniform, and reacted in a water bath at 30 ° C. for 1 hour.

After 1 hour, 8.4 mL of distilled water was added, and the mixture was reacted at 120 ° C. for 1 hour in an autoclave. After allowing to cool, ultrapure water was added and diluted appropriately. The diluted solution was subjected to ion chromatograph analysis manufactured by Thermo Fisher Scientific Co., Ltd., and the sugar component contained in the sample was analyzed.

(Iii) Measurement of average fiber diameter of lignocellulosic fibers An aqueous suspension of lignocellulosic fibers was dispersed in ethanol, and water was removed together with ethanol by filtration. The ethanol-wet product of the obtained filtration residue was dried under reduced pressure at room temperature. For this dried lignocellulosic product, a scanning electron microscope (SEM) photograph of 500 to 10,000 times was taken, and at least 50 or more fiber diameters were measured on the photograph taken, and an average value was calculated.

(Iv) Strength test of hot-pressed compact A hot-pressure compact with a thickness of 1 mm was cut into a length of 30 mm and a width of 5 mm using a cutter to obtain a sample. This sample was subjected to a three-point bending test using a universal testing machine (Instron model 3365 twin-column desktop test system) at a distance between fulcrums of 20 mm and a bending speed of 5 mm / min.

Four. Production Example Lignocellulosic fiber (raw material for thermal pressure molded products of Examples and Comparative Examples)
Manufacturing example 1
Ref-NCTMP (defibration by NCTMP refiner)
Water was added to the NCTMP (lignin content: 27% by mass) to prepare a pulp slurry having a solid content concentration of 3.0% by mass. This pulp slurry was defibrated using a refiner (lab refiner model SDR14 manufactured by Aikawa Iron Works Co., Ltd.) under the following conditions.

Defibering condition Processing amount: 30L
Flow rate: 600 mL / min
Temperature: 40-60 ℃
Time: about 10min
The obtained lignocellulosic fiber is called Ref-NCTMP.

The CSF was 60 mL.

Table 1 shows the average fiber diameter of Ref-NCTMP.

Manufacturing example 2
BM-NCTMP (NCTMP bead mill defibration)
Water was added to the NCTMP (lignin content: 27% by mass) to prepare a pulp slurry having a solid content concentration of 0.75% by mass. This pulp slurry was defibrated three times using a bead mill (IMEX Co., Ltd. model NVM-2) under the following conditions.

Defibering conditions Beads: Zirconia beads (Diameter: 1 mm)
Bead filling rate: 70%
Rotation speed: 2,000 rpm
Discharge rate: 600 mL / min
The obtained lignocellulosic fiber is called BM-NCTMP.

Manufacturing example 3
Ref-NUKP (defibration with NUKP refiner)
Lignocellulosic fibers were obtained in the same manner as in Production Example 1 except that the raw material was changed to NUKP (lignin content: 9.9% by mass).

The obtained lignocellulosic fiber is called Ref-NUKP.

Table 1 shows the average fiber diameter of Ref-NUKP.
The CSF was 50 mL.

Manufacturing example 4
Unbleached kraft pulp (BM-NUKP) derived from coniferous trees defibrated by a bead mill
Lignocellulosic fibers were obtained in the same manner as in Production Example 2 except that the raw material was changed to unbleached kraft pulp derived from coniferous trees (NUKP, lignin content: 9.9% by mass).

The obtained lignocellulosic fiber is called BM-NUKP.

Table 1 shows the average fiber diameter of BM-NUKP.

Table 1 summarizes the amount of lignin and the average fiber diameter of the lignocellulosic fibers obtained in the production example.

Five. Example
Example 1: Preparation of CM (BM-NUKP) and its hot-press molded product
Preparation of Chemically Modified Lignocellulosic In a 1 L 3-necked flask, 20 g of the lignocellulosic fiber (BM-NUKP) obtained in Production Example 4 in solid content, 160 g of water, 480 g of isopropanol (IPA), and 2.6 g of sodium hydroxide. Was charged, and the mixture was mixed and stirred at room temperature for 30 minutes. Subsequently, 2.4 g of monochloroacetic acid was added, and the mixture was further mixed and stirred for 30 minutes.

After that, the internal temperature of the flask was raised to 70 ° C. and held for 3 hours, and carboxymethylated (CM-ized) lignocellulosic fiber as a chemically modified lignocellulosic fiber [this chemically modified lignocellulosic fiber was referred to as CM (BM-NUKP). Call it. ] Sodium salt was obtained.

After cooling, the reaction mixture is taken out by neutralizing with a 2N aqueous hydrochloric acid solution, the solvent and water-soluble residual components are removed by filtration, diluted with water again, and filtration is repeated to wash the fiber aggregate of CM (BM-NUKP). did.

The degree of substitution (DS) of the obtained CM (BM-NUKP) in CM was 0.04.

DS has the meaning as described in the above section "Modes for Carrying Out the Invention".

The method of obtaining the degree of substitution (DS) for CM conversion is shown below.

DS is the number of carboxymethyl groups added per repeating unit.

The anionic ion equivalent (anionic group weight per weight) increased by the denaturation is calculated as follows using the apparent formula (B) per repeating unit of DS (α) and unmodified lignocellulosic. Can be represented.

A－A ₀ = α × 10 ³ / (B + 58 × α)
α: Addition rate of monochloroacetic acid (DS)
A: CMized lignocellulosic anionic ion equivalent [meq / g]
A ₀ : Anionic equivalent of unmodified lignocellulosic [meq / g]
B: Apparent formula amount of unmodified lignocellulosic If this formula is arranged for α, DS (α) can be obtained by the following formula.

α = B × (A-A ₀ ) / {1,000-58 × (A-A ₀ )}
The anionic ion equivalent (A or A ₀ ) was calculated by the methanol nitrate method.

The CM-ized or unmodified lignocellulosic-containing slurry was weighed so that the weight of the dried product was about 2 g, and placed in a 300 mL Erlenmeyer flask. 100 mL of methanol nitrate (a solution of 1 liter of anhydrous methanol plus 100 mL of special grade concentrated nitric acid) was added to this 300 mL Erlenmeyer flask, and the contents of the 300 mL Erlenmeyer flask were shaken for 3 hours to obtain a pulp slurry.

After filtering this pulp slurry, in order to remove the remaining water-soluble chemicals, put the filtration residue in a 300 mL glass container, add 100 mL of 80% methanol (mixture of 80 g of anhydrous methanol and 20 g of water), and stir. , The operation of filtering again was repeated 3 times. 80% methanol was added to the obtained filtration residue to moisten it, 100 mL of 0.1N sodium hydroxide aqueous solution was added, and the mixture was stirred at room temperature for 3 hours to obtain a pulp slurry.

To this pulp slurry, an excess amount of sodium hydroxide was titrated with 0.1N sulfuric acid using phenolphthalein as an indicator.

The anionic ion equivalent was calculated by the following formula.

CMized or unmodified lignocellulosic anionic ion equivalent = (F ₁ − F ₂ ) × 0.1 / W
F ₁ : Addition amount of 0.1N sodium hydroxide [mL]
F ₂ : Titration of 0.1N sulfuric acid [mL]
The apparent formula (B) of unmodified lignocellulosic was calculated by the following formula.

B = {196 x L _m + 162 x (100-L _m )} / 100
L _m : Molar ratio of lignin contained in unmodified lignocellulosic [mol%]
The molar ratio (L _m ) of lignin contained in unmodified lignocellulosic was calculated by the following formula.

L _m = (L _w / 196) / {(L _w / 196) + (100-L _w ) / 162} × 100
L _w : Weight ratio of lignin contained in unmodified lignocellulosic [wt%]
The weight ratio (L _w ) of lignin contained in unmodified lignocellulosic was measured by the Clarson method.

The glass fiber filter paper ( _GA55 ) was dried in a 105 ° C oven to a constant weight, allowed to cool in a desiccator, and then weighed (WF). Weigh lignocellulosic (sample about 0.2 g) dried in an oven at 105 ° C until it reaches a constant weight (W ₀ ), add 3 mL of 72% sulfuric acid, and crush it appropriately with a glass rod so that the contents are uniform. It was kept in a hot water bath at 30 ° C for 1 hour.

Then, 84 g of distilled water was added to the contents, and the mixture was kept in an autoclave at 120 ° C. for 1 hour. After allowing to cool, the contents were filtered through a glass fiber filter paper and washed with 200 mL of distilled water.

The obtained filtration residue and glass fiber filter paper are dried in an oven at 105 ° _C until they reach a constant weight (W _total ), and the weight of the glass fiber filter paper (WF) is subtracted to calculate the pulp weight after lignin removal. (W ₁ = W _{total -WF} ).

The weight ratio (L _w ) of lignin contained in unmodified lignocellulosic was calculated by the following formula.

L _w = (W ₀ －W ₁ ) / W ₀ × 100
The formula amount of unmodified lignocellulosic (calculated in consideration of the mole fraction of cellulose, lignin and hemicellulose in lignocellulosic) is usually used for the calculation of DS. As described above, there is almost no error in calculating DS using the apparent formula (B) calculated using only the mole fractions of cellulose and lignin instead of the formula of lignocellulosic. Five%). In the present invention, DS was calculated by the above formula.

Thermal pressure molding of chemically modified lignocellulosic The above CM (BM-NUKP) fiber aggregate is dried, sealed in a mold, heated to 200 ° C, and held at 100 MPa for 3 minutes to make it thicker. A heat-press molded product of chemically modified lignocellulosic [CM (BM-NUKP)] having a thickness of 1 mm was obtained.

The obtained thermal pressure molded product was cut into a length of 30 mm and a width of 5 mm using a cutter to obtain a sample. This sample was subjected to a three-point bending test using a universal testing machine (Instron model 3365 twin-column desktop test system) at a distance between fulcrums of 20 mm and a bending speed of 5 mm / min.

As a result, the sample had a flexural strength of 217 MPa and a flexural modulus of 10.7 GPa.

The production conditions of the CM-modified lignocellulosic fiber, the production conditions of the CM-modified lignocellulosic modified molded product, and the measurement results of physical properties are summarized in Tables 2 and 3, respectively.

Example 2
A hot-press molded product of CM-formed lignocellulosic was obtained in the same manner as in Example 1 except that the pressurization condition in hot-press molding was changed to 30 MPa. As a result of the bending test of the hot-pressure molded product, the bending strength was 207 MPa and the flexural modulus was 9.7 GPa.

The production conditions of the CM-modified lignocellulosic fiber, the production conditions of the CM-modified lignocellulosic modified molded product, and the measurement results of physical properties are summarized in Tables 2 and 3, respectively.

Examples 3-6
CM-modified lignocellulosic fibers were obtained in the same manner as in Example 1 except that the amounts of lignocellulosic and the reagents to be added were changed to the amounts shown in Table 2, and then CM-modified lignocellulosic fibers were obtained under the production conditions shown in Table 3. A hot pressure molded product was obtained.

Table 2 shows the physical characteristics of the obtained CM-ized lignocellulosic fiber. Table 3 shows the physical properties of the heat-press molded body of CM-ized lignocellulosic. The density of the hot-pressed body was also measured and shown in Table 3.

In the table, the meanings of the following abbreviations are as follows.
CM: Carboxymethylation
AS: Alkenyl succinic acid half esterification
BM: What was defibrated with a bead mill
Ref: What was defibrated with a refiner
NUKP: Unbleached kraft pulp from coniferous trees
NCTMP: Chemical thermomechanical pulp derived from coniferous trees.

Therefore, CM (BM-NUKP) means a chemically modified lignocellulosic fiber obtained by defibrating unbleached kraft pulp derived from coniferous tree with a bead mill to obtain lignocellulosic fiber and carboxymethylating the lignocellulosic fiber.

Example 7: Preparation of AS (BM-NUKP) and its hot-press molded product
Preparation of chemically modified (AS modified) lignocellulosic fibers
Lignocellulosic (BM-NUKP) fiber obtained in Production Example 4 above was charged with 20 g of solid content and 650 g of N-methylpyrrolidone (NMP) in a 1 L three-necked flask, and dehydrated under reduced pressure at 80 ° C. with stirring. ..

Subsequently, nitrogen was introduced and returned to normal pressure, and 5.6 g of alkenyl succinic anhydride (T-NS135 manufactured by Seikou PMC Co., Ltd., 16 carbon atoms other than anhydrous succinic anhydride) and 1.2 g of potassium carbonate were added, and the temperature was 80 ° C. The mixture was kept as it was for 3 hours to obtain a potassium salt of AS-modified lignocellulosic [this is called AS (BM-NUKP)] as a chemically modified lignocellulosic fiber.

After cooling, the reaction mixture was placed in a 2N aqueous hydrochloric acid solution to neutralize, and the solvent and water-soluble residual components were removed by filtration. Further, by repeating dilution and filtration sequentially with acetone, ethanol and water, a fiber aggregate of chemically modified lignocellulosic [AS (BM-NUKP)] was obtained.

The degree of substitution (DS) of the obtained chemically modified lignocellulosic [AS (BM-NUKP)] was 0.13.

Table 4 summarizes the production conditions and physical properties of chemically modified (AS-modified) lignocellulosic.

DS has the meaning as described in the above section [Modes for Carrying Out the Invention].

The method of obtaining the DS of AS conversion is shown below.

DS is the number of ASAs added per repeating unit.

The added equivalent of ASA (the amount of ASA added per weight of modified lignocellulosic) is the DS (α), the molecular weight of ASA (M), and the apparent formula amount per repeating unit of unmodified lignocellulosic (B). Can be expressed as follows using.

A = α × 10 ³ / (B ＋ M × α)
α: ASA addition rate (DS)
A: ASA additional equivalent [meq / g]
B: Apparent formula amount of unmodified lignocellulosic If this formula is arranged for α, DS (α) can be obtained by the following formula.

α = B × A / {1,000-M × A}
The added equivalent of ASA was measured and calculated by the following method.

The ASA-added lignocellulosic-containing slurry was weighed to a dry matter weight of approximately 0.5 g and placed in a 100 mL beaker. To this, 15 mL of ethanol and 5 mL of water were added, and the mixture was stirred at room temperature for 30 minutes to obtain a pulp slurry. Subsequently, 10 mL of 0.5N sodium hydroxide solution was added, and the mixture was stirred at 70 ° C. for 15 minutes, cooled to room temperature, and further stirred overnight.

To the obtained mixed solution, an excess amount of sodium hydroxide was titrated with a 0.1 N hydrochloric acid aqueous solution using phenolphthalein as an indicator.

The additional equivalent of the above ASA was calculated by the following formula.

ASA additional equivalent = (F ₁ x 0.5-F ₂ x 0.1-A ₀ x W) / 2 / W
F ₁ : Addition amount of 0.5N sodium hydroxide [mL]
F ₂ : Titration of 0.1N hydrochloric acid [mL]
W: Dry weight of weighed ASA-added or unmodified lignocellulosic [g]
A ₀ : Anionic ion equivalent of unmodified lignocellulosic [meq / g]
The apparent formula (B) of unmodified lignocellulosic was calculated by the above method.

Thermal pressure molding of chemically modified (AS-modified) lignocellulosic The above-mentioned fiber aggregate of chemically modified lignocellulosic [AS (BM-NUKP]] fibers was dried and sealed in a mold. Then, heated to 200 ° C. to 100 MPa. By holding for 3 minutes in a pressurized state, a heat-press molded product (Example 7) of chemically modified (AS-modified) lignocellulosic [AS (BM-NUKP]) was obtained.

The obtained thermal pressure molded product was cut into a length of 30 mm and a width of 5 mm using a cutter to obtain a sample. This sample was subjected to a three-point bending test using a universal testing machine (Instron model 3365 twin-column desktop test system) at a distance between fulcrums of 20 mm and a bending speed of 5 mm / min.

As a result, the thermal pressure molded product had a bending strength of 197 MPa and a flexural modulus of 10.2 GPa.

The results are summarized in Table 5.

Examples 8 to 13
The lignocellulosic fiber (raw material of the chemically modified fiber) was chemically modified under the conditions shown in Table 4 to obtain AS-modified lignocellulosic fiber. Then, the solvent in which the AS-modified lignocellulosic fiber aggregate was dispersed was changed to obtain a fiber aggregate. This was processed under the shapes and thermal pressure conditions shown in Table 5 to obtain the thermal pressure molded products of Examples 8 to 13.

The results of the bending test measured in the same manner as in Example 7 are also shown in Table 5.

The density of the hot-pressed body was also measured and is shown in Table 5.

Comparative Example 1
The water-wet product of the lignocellulosic fiber obtained in Production Example 2 was repeatedly diluted with ethanol and filtered to obtain an aggregate of the lignocellulosic fiber.

The obtained fiber aggregate was dried, sealed in a mold, heated to 200 ° C., and held at 50 MPa for 3 minutes to obtain a fiber aggregate of unmodified lignocellulosic having a thickness of 1 mm. rice field.

The obtained lignocellulosic fiber aggregate was cut into a length of 30 mm and a width of 5 mm using a cutter to obtain a sample. This sample was subjected to a three-point bending test using a universal testing machine (Instron model 3365 twin-column desktop test system) at a distance between fulcrums of 20 mm and a bending speed of 5 mm / min.

As a result, the obtained lignocellulosic fiber aggregate had a bending strength of 166 MPa and a flexural modulus of 7.3 GPa. The density was 1.30 g / cm ³ .

Table 6 summarizes the physical properties of the above lignocellulosic fibers, and Table 7 summarizes the production conditions and the measurement results of the physical properties of the lignocellulosic fiber aggregate.

Comparative Examples 2 and 3
Lignocellulosic fiber aggregates were obtained in the same manner as in Comparative Example 1 except that the production conditions of the lignocellulosic fibers and the thermostatically molded product were changed as shown in Tables 6 and 7.

Table 7 summarizes the results of measuring the physical properties of the obtained lignocellulosic fiber aggregates.

Summary of Examples and Comparative Examples Table 8 summarizes the test results of Examples and Comparative Examples.

Discussion The reason why the heat-pressure molded product of the present invention, which exhibits excellent effects, was obtained by hot-pressing a chemically modified lignocellulosic fiber, is considered as follows.

The structure of the heat-pressure molded product of the present invention is (i) a matrix of lignin contained in the chemically modified lignocellulose fiber as a raw material, chemically modified lignin, hemicellulose, and chemically modified hemicellulose (ii). ) Cellulose nanofibers (CNF) and chemically modified cellulose are used as fillers, and can be said to be nanocomposites.

Generally, in the design of nanocomposites, the thermoplasticity of the matrix component, the uniform dispersion of the filler in the matrix component, and the affinity between the matrix component and the filler are important. In the present invention, the chemical modification of the hydroxyl groups of lignin and hemicellulose functions effectively in order to make the thermoplasticity of the matrix component suitable. Although lignin exhibits thermoplasticity even in the unmodified state, it is considered that the functional group inhibits the interconnection action between lignins by chemical modification, and the thermoplasticity is improved.

Hemicellulose usually binds to each other by hydrogen bonds due to hydroxyl groups and exhibits almost no thermoplasticity. In the present invention, it is considered that the thermoplasticity of hemicellulose is also improved by inhibiting this hydrogen bond by chemical modification.

It is considered that the chemical modification of the hydroxyl group of hemicellulose also functions effectively for the uniform dispersion of the filler in the matrix component. In the unmodified state, hemicellulose plays a role of bundling CNF, but it is considered that CNF is released from the bundled state by improving the thermoplasticity of hemicellulose as described above.

In wood-based materials, hemicellulose bundles a plurality of CNFs, and lignin hardens the aggregate as an adhesive, so that the affinity between the matrix component and the filler is maintained. Since the degree of chemical modification is appropriately controlled in the present invention, it is considered that the degree of chemical modification is suppressed to the extent that this naturally derived function is not impaired.

It is considered that these effects are combined and act synergistically to obtain the effect of the present invention.
The reasons why the functional groups represented by the formulas (1) and (2) are excellent as the functional groups to be introduced by chemical modification are the inhibition of hydrogen bonds, the inhibition of the interaction between lignins, lignin, hemicellulose, and CNF. It is thought that this is because the balance is excellent, such as not impairing the affinity of.

Claims (12)

A heat-press molded product of chemically modified lignocellulosic
The density of the heat-press molded product is 1.1 to 1.5 g / cm ³ , and the density is 1.1 to 1.5 g / cm 3.
The heat-press molded product does not contain resin and does not contain resin.
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4. The thermal pressure molded product according to claim 1.
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-1) A part of the hydroxyl group existing in the lignocellulosic is the following formula (1) :.

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4. The thermal pressure molded product according to claim 1.
The chemically modified lignocellulosic has the properties of (a) and (b).
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n is an integer of 1.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.3. The heat-pressure molded product according to any one of claims 1 to 3.
The content of the lignin component of the chemically modified lignocellulosic is 2 to 40% by mass.
Thermal pressure molded body. A method for producing a heat-press molded product of chemically modified lignocellulosic.
The density of the heat-press molded product is 1.1 to 1.5 g / cm ³ , and the density is 1.1 to 1.5 g / cm 3.
The heat-press molded product does not contain resin and does not contain resin.
Including the step of compressing a fiber aggregate composed of chemically modified lignocellulosic fibers under heating.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-1) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (1):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Or,
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.01 to 0.4.
Or,
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.4. The method for manufacturing a thermal pressure molded product according to claim 5.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-1) A part of the hydroxyl group existing in the lignocellulosic is the following formula (1) :.

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
Being half-esterified with a carboxy group-containing acyl group represented by
Characteristic (b)
(B-1) The degree of substitution of the hydrogen atom of the hydroxyl group in the half-esterified lignocellulosic is 0.1 to 0.4. The method for manufacturing a thermal pressure molded product according to claim 5.
A method for producing a heat-press molded product, wherein the chemically modified lignocellulosic fiber has the characteristics of (a) and (b):
Characteristics (a)
(A-2) Some of the hydroxyl groups present in lignocellulosic are described in the following formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n is an integer of 1.)
Being etherified with a carboxyalkyl group represented by
Characteristic (b)
(B-2) The degree of substitution of the hydrogen atom of the hydroxyl group in the etherified lignocellulosic is 0.01 to 0.3. The method for manufacturing a thermal pressure molded product according to any one of claims 5 to 7.
The average fiber diameter of the chemically modified lignocellulosic fiber is 20 nm to 50 μm.
A method for manufacturing a thermal pressure molded product. The method for manufacturing a thermal pressure molded product according to any one of claims 5 to 8.
A method for producing a hot-pressure molded product, wherein the chemically modified lignocellulosic fiber has a lignin component content of 2 to 40% by mass. The method for manufacturing a thermal pressure molded product according to any one of claims 5 to 9.
A method for producing a hot-pressure molded body, wherein the fiber aggregate made of the chemically modified lignocellulosic fiber is heated at a temperature of 160 to 240 ° C. and a compression pressure of 30 MPa to 100 MPa. A method for producing a heat-press molded product of chemically modified lignocellulosic.
The density of the heat-press molded product is 1.1 to 1.5 g / cm ³ , and the density is 1.1 to 1.5 g / cm 3.
The heat-press molded product does not contain resin and does not contain resin.
A method for manufacturing a hot-pressed molded product, which comprises the following first and second steps:
(1) First step :
(A-1) For lignocellulosic fiber, the following formula (3):

(In the formula, R ¹ and R ² each indicate an alkenyl group or an alkyl group having 3 to 20 carbon atoms which may have a hydrogen atom, a methyl group, an ethyl group or a branched chain, respectively. However, R ¹ and R ² are shown. When either one of the carbon atoms is 4 to 20, one of R ¹ and R ² is a hydrogen atom.)
The following formula (1)::

(In the formula, R ¹ and R ² are the same as above.)
By half-esterifying with a carboxy group-containing acyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the lignocellulosic to be half-esterified to 0.01 to 0.4.
Or,
(A-2) For lignocellulosic fiber, the following formula (4):
X- (CH ₂ ) _n -COOH ・ ・ ・ ・ (4)
(In the formula, n represents an integer of 1 to 3. X represents a halogen atom selected from the group consisting of Cl, Br and I.)
By reacting the halogenoalkylcarboxylic acid represented by the above formula (2):
-(CH ₂ ) _n -COOH ・ ・ ・ ・ (2)
(In the formula, n indicates an integer from 1 to 3.)
By etherifying with a carboxyalkyl group represented by
A step of producing a chemically modified lignocellulosic fiber by setting the degree of substitution of a hydrogen atom of a hydroxyl group in the etherified lignocellulosic to 0.01 to 0.4.
(2) Second step :
A step of compressing a fiber aggregate made of chemically modified lignocellulosic fibers obtained in the first step under heating. The method for producing a thermally compacted body according to claim 11, wherein the fiber aggregate made of the chemically modified lignocellulose fiber is heated at a temperature of 160 to 240 ° C. and compressed at a pressure of 30 MPa to 100 MPa. A method for manufacturing a thermal pressure molded body.