JP7185215B2 - Fiber-reinforced resin composition, fiber-reinforced molded article, and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fiber-reinforced resin composition, a fiber-reinforced molded article, and a method for producing the same.

More specifically, the present invention relates to a fiber-reinforced thermoplastic resin composition containing cellulosic fibers and an inorganic filler, a molded article thereof, and a method for producing the same.

In order to maintain or improve the global environment, there is a demand for the development of materials that ensure mechanical properties and functionality and that are less burdensome to humans and the environment during production, use and disposal.

Fiber reinforced resin compositions are used in a wide range of fields such as automobile parts, aircraft interior parts, household equipment, construction materials, etc. It has been.

In the automobile industry, there is an urgent need to reduce the weight of automobile bodies in order to combat global warming (carbon dioxide), improve the fuel efficiency of vehicles equipped with internal combustion engines, and improve the energy efficiency of hybrid vehicles and vehicles equipped with batteries. In the automobile industry, the replacement of conventional steel structures with structures made of fiber-reinforced resin compositions is accelerating.

With respect to matrix resins used in such fiber-reinforced resin compositions, thermoplastic resins among various resins are attracting attention due to their excellent productivity and versatility.

Examples of molding methods for fiber-reinforced resin compositions include injection molding, press molding, RTM (Resin Transfer Molding), autoclave, and prepreg. Among them, the injection molding method has a high molding speed (high productivity), so the cost in the molding process is low, and it is easy to mold complicated shapes, so it is superior in terms of productivity and manufacturing cost. .

The fibers used in the structure (molded body) of such a fiber-reinforced resin composition are required to have performance such as high rigidity, high strength and impact resistance of the structure (molded body). GF), carbon fiber (CF), etc. are widely applied. However, inorganic fibers such as glass fibers and carbon fibers consume a large amount of energy during production, and the disposal and recycling systems have not yet been fully established.

Therefore, in consideration of further weight reduction of the structure, natural fiber reinforced resins using natural fibers having a smaller specific gravity than these inorganic fibers, fiber reinforced resin compositions using both inorganic fibers and natural fibers, etc. have been proposed. there is

Patent Document 1 discloses a resin composition containing fine cellulose fibers or glass fibers.

Patent Document 2 discloses a composite resin composition containing carbon fibers and a resin, and further discloses that natural fibers such as wood fibers and cotton may be combined.

Patent Document 3 discloses a composition comprising glass fibers, cellulose and a thermoplastic resin.

Patent Document 4 discloses a resin molding containing a thermoplastic resin, 1 to 6% by weight of glass fiber, and 10 to 40% by weight of vegetable fiber having a fiber length of 0.3 mm or less.

Patent Document 5 discloses a composite material containing a filler selected from the group of wood flour, cellulose fiber, metal powder, oxide, etc. with a particle size of about 2 to 500 μm in addition to polyolefin and glass fiber. there is

Patent Document 6 describes at least one type of fiber (filler) selected from the group consisting of inorganic fibers such as carbon fibers and glass fibers, vegetable fibers such as kenaf and cellulose fibers, and synthetic fibers such as polyvinyl alcohol fibers and polyimide fibers. and a biodegradable polymer are kneaded together.

Patent Document 7 discloses a fiber-reinforced resin molding containing carbon fiber, kenaf, hemp, cellulosic plant fiber and biomass resin, and discloses that the average diameter of the plant fiber used is 5 μm to 30 μm. ing.

Patent Documents 8 and 9 disclose a plant-based resin-containing composition comprising polyamide 11 and at least one additive selected from the group consisting of silica, wollastonite, vegetable fibers, glass flakes, glass fibers, and talc. things are disclosed.

The above Patent Documents 1 to 9 disclose that inorganic fibers such as glass fibers and carbon fibers and cellulose fibers (vegetable fibers) can be used in fiber-reinforced resin compositions. However, Patent Documents 1 to 9 do not specifically describe the combined use of inorganic fibers such as glass fibers and carbon fibers and fibrillated cellulose fibers (fibrillated vegetable fibers). There is also no mention of the effects achieved by their combined use.

20-79% by mass of semi-aromatic polyamide, 1-15% by mass of at least one impact modifier, 20-60% by mass of carbon fiber, and 0-5% by mass of additives. Polyamide molding compositions are disclosed comprising (glass fibers, mineral powders, etc.). However, the composition of Patent Document 10 does not contain cellulosic fibers.

Patent Document 11 discloses a composition containing a biogenic reinforcing material (plant fiber, animal fiber, biogenic polymer, biogenic carbon fiber, biogenic carbon nanotube, etc.) and an aromatic polyamide, An example using cellulose microfibrils as the plant fiber is described. However, Patent Document 11 does not describe a composition in which inorganic fibers (carbon fibers, glass fibers, etc.) and microfibrillated cellulose are used in combination, and also describes the effect of using the two types of fibers in combination. It has not been.

US Pat. Nos. 5,300,000 and 5,000,000 disclose epoxy resin compositions comprising glass fibers, cellulose fibers, carbon fibers and combinations thereof. However, the inventions described in Patent Documents 12 and 13 are not techniques that use microfibrillated cellulose or chemically modified cellulose as cellulose fibers.

Patent Document 14 is a patent in which the present inventor is included among the inventors. US Pat. No. 5,300,004 discloses fiber-reinforced thermoset resins containing microfibrillated cellulose fibers modified with a specific degree of substitution of carboxyalkyl groups.

Patent Document 15 is a patent in which the present inventor is included among the inventors. Patent Document 15 discloses a fiber-reinforced thermoplastic resin containing microfibrillated cellulose fibers or microfibrillated lignocellulose fibers modified with acetyl groups.

However, Patent Documents 14 and 15 do not disclose a resin composition containing glass fibers or carbon fibers.

JP 2013-181084 A JP 2014-101459 A Japanese Patent Application Laid-Open No. 2010-155970 Japanese Patent Publication No. 2013-183440 JP-A-11-323036 JP-A-2005-138458 Japanese Patent Publication No. 2008-105225 JP 2011-236443 A Japanese Patent Publication No. 2007-34905 Japanese Patent Publication No. 2016-538390 Japanese Patent Publication No. 2012-509381 Japanese Patent Publication No. 2014-517126 JP 2014-118576 A Patent No. 5622412 (JP 2011-195738) Patent No. 6091589 (JP 2016-176052)

Each of the above documents discloses a fiber-reinforced resin composition containing (1) chemically modified microfibrillated cellulose fibers or chemically modified microfibrillated lignocellulose fibers and (2) inorganic fibers such as glass fibers and carbon fibers. Also, (1) chemically modified microfibrillated cellulose fibers or chemically modified microfibrillated lignocellulose fibers and (2) inorganic fibers such as glass fibers and carbon fibers are used in combination as reinforcing materials for the resin composition. There is also no specific disclosure of the effect of the case.

An object of the present invention is to provide a fiber-reinforced resin composition that is lightweight and has excellent strength properties, a molded article thereof, and a method for producing the same.

An object of the present invention is to provide a fiber-reinforced resin composition containing (A) a specific chemically modified microfibrillated cellulose fiber, (B) an inorganic filler, and (C) a thermoplastic resin, and a molding thereof. bodies, as well as methods for their manufacture.

The terms used in the present invention have the following meanings.

"Cellulosic polymer" means at least one kind of polymer selected from the group consisting of cellulose, holocellulose and lignocellulose, represented by the general formula "(Lg)Cell-OH". Here, "(Lg)Cell-" means a residue obtained by removing hydroxyl groups from polysaccharides and lignin constituting at least one type of polymer selected from the group of polymers consisting of cellulose, holocellulose and lignocellulose.

"Cellulosic fiber" means a fiber composed of at least one polymer selected from the group consisting of cellulose, holocellulose and lignocellulose. That is, the cellulosic fiber referred to in the present invention means a fiber composed of a cellulosic polymer "(Lg)Cell-OH".

"Microfibrillated cellulosic fiber" means a cellulosic fiber that has been microfibrillated. Hereinafter, "microfibrillated cellulose fiber" may be referred to as "MFC".

"Chemically modified cellulosic fiber" means that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in "(Lg)Cell-OH" that constitutes cellulosic fiber are It means a fiber consisting of macromolecules substituted with functional groups (R). In this specification, "chemically modified cellulosic fiber" is referred to as "(Lg)Cell-O-R".

"Chemically modified microfibrillated cellulosic fiber" means a fiber in which the chemically modified cellulosic fiber is microfibrillated. It is also a fiber in which hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in microfibrillated cellulosic fibers are substituted with functional groups (R). Hereinafter, "chemically modified microfibrillated cellulose fiber" may be referred to as "chemically modified MFC".

"Lignocellulose" means a material in which lignin and cellulose are combined and/or mixtures of lignin and cellulose present in plants with or without lignin content. Hereinafter, "lignocellulose" may be referred to as "LC".

"Lignopulp" means pulp containing lignocellulose. Hereinafter, "lignopulp" may be referred to as "LP".

"Cellulosic pulp" means fibers made of cellulosic macromolecules, isolated from plants. This includes lignin-free pulps (cellulose-based pulps, holo-cellulose-based pulps, etc.) and lignin-containing pulps (lignopulps). Hereinafter, "cellulose pulp" may be referred to as "CP".

The present invention relates to a fiber-reinforced resin composition containing chemically modified microfibrillated cellulose fibers and an inorganic filler, a molded article thereof, and a method for producing the same, which are described in the following items.

Item 1. Fiber-reinforced resin composition . A fiber-reinforced resin composition,
The fiber-reinforced resin composition contains (A) chemically modified microfibrillated cellulose fibers, (B) an inorganic filler and (C) a thermoplastic resin,
A fiber-reinforced resin composition in which the (A) chemically modified microfibrillated cellulose fiber and the (B) inorganic filler satisfy the following requirements (a) and (b):
(a) (A) chemically modified microfibrillated cellulosic fibers are
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

Section 2.
R in formula (1) of the above requirement (a) is an acetyl group, a propionyl group, a carboxymethyl group, a salt of a carboxymethyl group, a carboxyethyl group, a salt of a carboxyethyl group, a carboxyethylcarbonyl group, or a carboxyethylcarbonyl group. Item 1. The fiber-reinforced resin composition according to Item 1, which is a salt, a carboxyvinylcarbonyl group, or a salt of a carboxyvinylcarbonyl group.

Item 3.
3. The fiber-reinforced resin composition according to item 1 or 2, wherein R in formula (1) of the requirement (a) is an acetyl group.

Section 4.
4. The fiber-reinforced resin composition according to any one of items 1 to 3, wherein the inorganic filler (B) in the requirement (b) is glass fiber or carbon fiber.

Item 5.
5. The fiber-reinforced resin according to any one of items 1 to 4, wherein (Lg)Cell- in the formula (1) of the (a) requirement is a residue obtained by removing hydroxyl groups from polysaccharides and lignin constituting lignocellulose. Composition.

Item 6.
The (C) thermoplastic resin is polyamide, polyolefin, aliphatic polyester, aromatic polyester, polyacetal, polycarbonate, polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), polycarbonate-ABS alloy (PC-ABS alloy). and modified polyphenylene ether (m-PPE).

Item 7. Molded article .
A molded article comprising the fiber-reinforced resin composition according to any one of Items 1 to 6.

Item 8. Manufacturing method of fiber reinforced resin composition .
A method for producing a fiber-reinforced resin composition,
(i) Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
A chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by
(ii) (B) inorganic filler, and (iii) (C) thermoplastic resin are melt-kneaded to obtain (A) chemically modified microfibrillated cellulosic fiber, (B) inorganic filler, and (C) thermoplastic resin. wherein the (A) chemically modified microfibrillated cellulose fiber and the (B) inorganic filler meet the requirements of the following (a) and (b): fiber reinforced resin Method of making the composition:
(a) (A) Chemically modified microfibrillated cellulosic fibers are represented by the following formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

Item 8 (2).
7. A method for producing a fiber-reinforced resin composition according to any one of items 1 to 6,
(i) Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
A chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by
(ii) (B) inorganic filler, and (iii) (C) thermoplastic resin are melt-kneaded to obtain (A) chemically modified microfibrillated cellulosic fiber, (B) inorganic filler, and (C) thermoplastic resin. wherein the (A) chemically modified microfibrillated cellulose fiber and the (B) inorganic filler satisfy the requirements of (a) and (b) above. A method of making the composition.

Item 9.
A method for producing a fiber-reinforced resin composition,
Process (1):
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
Chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by and (C) a step of kneading a thermoplastic resin, and
Step (2):
(A) a chemically modified microfibrillated cellulose fiber by a method comprising a step of melt-kneading the kneaded product obtained in the step (1) and (B) a resin composition containing an inorganic filler and a thermoplastic resin; , (B) an inorganic filler and (C) a method for producing a fiber-reinforced resin composition containing a thermoplastic resin,
A method for producing a fiber-reinforced resin composition in which the (A) chemically modified microfibrillated cellulose fibers and the (B) inorganic filler satisfy the following requirements (a) and (b):
(a) (A) Chemically modified microfibrillated cellulosic fibers are represented by the following formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

Item 9 (2).
7. A method for producing a fiber-reinforced resin composition according to any one of items 1 to 6,
Process (1):
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
Chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by and (C) a step of kneading a thermoplastic resin, and
Step (2):
(A) a chemically modified microfibrillated cellulose fiber by a method comprising a step of melt-kneading the kneaded product obtained in the step (1) and (B) a resin composition containing an inorganic filler and a thermoplastic resin; , (B) an inorganic filler and (C) a method for producing a fiber-reinforced resin composition containing a thermoplastic resin,
A method for producing a fiber-reinforced resin composition, wherein the (A) chemically modified microfibrillated cellulose fibers and the (B) inorganic filler satisfy the requirements of (a) and (b).

The fiber-reinforced resin composition of the present invention contains specific chemically modified microfibrillated cellulose fibers and inorganic fillers such as glass fibers and carbon fibers.

The fiber-reinforced resin composition of the present invention has a reduced specific gravity and high strength characteristics (elastic modulus and strength) of the molded product compared to conventional fiber-reinforced resin compositions containing only inorganic fillers.

That is, by including both the chemically modified fibrillated cellulose-based fiber and the inorganic filler in the resin composition, the molded article of the fiber-reinforced resin composition of the present invention has a particularly good bending elastic modulus per density (flexural elastic modulus/ A synergistic effect is observed in the improvement of density).

For example, when comparing the bending elastic modulus per density (MPa / composition density) of a molded body made of a conventional PA6 composition containing 20 Wt% of glass fiber (GF) (conventional product), the composition of the present invention The compacts PA6-429 (PA6/AcNBKP/GF = 85/5/10), PA6-431 (PA6/AcNBKP/GF = 85/10/5), and PA6-432 (PA6/AcNBKP/GF = 80/ 10/10), the flexural modulus per density is 1.20 to 1.42 times.

Furthermore, the bending strength per density (MPa/composition density) of the molded product of the present invention made of the above composition is 1.07 to 1.16 times that of the conventional product (see Table 5 below).

Compositions containing glass wool (GW) were also compared on the basis of the flexural modulus per density (MPa/composition density) of a molded body made of a conventional PA6 composition containing GW 20 Wt%, and the composition of the present invention was found to be The flexural modulus per density (MPa/composition density) of the molded body made of this was 1.31 to 1.78 times, and the flexural strength per density (MPa/composition density) was 1.35 to 1.48 times.

(See test numbers in Table 9 below: PA6-448 (PA6/AcNBKP/GW = 90/5/5), PA6-449 (PA6/AcNBKP/GW = 85/5/10), PA6-451 (PA6/AcNBKP /GW = 85/10/5), and PA6-452 (PA6/AcNBKP/GW = 80/10/10).

In addition, since the fiber-reinforced resin composition of the present invention can be molded by an injection molding method, the molded product can be produced with high productivity and at a low production cost.

In addition, in the fiber-reinforced resin composition of the present invention, when the chemically modified fibrillated cellulose fiber and the inorganic filler are used in combination, the complex viscosity is lowered, resulting in good moldability.

In addition, the fiber-reinforced resin composition of the present invention employs a step of melt-kneading the chemically modified cellulose fiber, the inorganic filler and the resin in its production, whereby the melt-kneading and the chemically modified cellulose fiber (chemically modified pulp) are combined. Since microfibrillation can be performed at the same time, productivity is also high.

FIG. 4 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.69) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between density and bending strength of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.69) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between density and bending strength of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between density and flexural modulus of PA6 molded bodies containing acetylated NBKP (AcNBKP, DS=0.67) and glass wool (GW). FIG. 4 is a diagram showing the relationship between density and bending strength of a PA6 compact containing acetylated NBKP (AcNBKP, DS=0.67) and glass wool (GW). FIG. 4 is a diagram showing the relationship between the density and flexural modulus of a PC-ABS alloy molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between the density and bending strength of a PC-ABS alloy molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF). FIG. 4 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.62) and carbon fiber (CF). FIG. 4 is a diagram showing the relationship between the density and bending strength of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.62) and carbon fiber (CF). 1 is an electron microscopic image of AcNBKP (AcNBKP before melt-kneading with PA6) used for a compact with test number PA6-430. 1 is an electron microscope image of fibers in a sample prepared from a compact with test number PA6-430. 1 is an electron microscope image of fibers in a sample prepared from a compact of Test No. PA6-431. 1 is an electron microscope image of fibers in a sample prepared from a compact of Test No. PA6-451.

(1) Fiber-reinforced resin composition The fiber-reinforced resin composition of the present invention contains (A) chemically modified microfibrillated cellulose fibers, (B) an inorganic filler, and (C) a thermoplastic resin.

The present invention is a fiber-reinforced resin composition in which the (A) chemically modified microfibrillated cellulose fibers and the (B) inorganic filler satisfy the following requirements (a) and (b).

Requirement (a)
(A) chemically modified microfibrillated cellulosic fibers are
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.

Requirement (b)
(B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

(1-1) (A) Chemically modified microfibrillated cellulose fiber (chemically modified MFC)
In the present invention, at least one type of polymer selected from the group (polymer group) consisting of cellulose, holocellulose and lignocellulose is referred to as a cellulosic polymer and represented by the general formula "(Lg)Cell-OH". .

Here, "(Lg)Cell-" means a residue obtained by removing hydroxyl groups from polysaccharides and lignin constituting at least one type of polymer selected from the group of polymers consisting of cellulose, holocellulose and lignocellulose.

In the chemically modified cellulosic fiber used in the present invention, hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in (Lg)Cell-OH are functional groups R ( The details of R will be described later), that is, the following formula (1): (Lg)Cell-OR (1)
It is a fiber composed of a chemically modified cellulosic polymer represented by.

The chemically modified microfibrillated cellulose fiber (chemically modified MFC) used in the present invention is a fiber obtained by microfibrillating the chemically modified cellulose fiber represented by the above formula (1).

In addition, the chemically modified MFC used in the present invention includes cellulose, holocellulose and/or It can also be said that the lignocellulose is a fiber in which the hydrogen atoms of some hydroxyl groups of polysaccharides and lignin in lignocellulose are substituted with functional groups R.

The chemically modified MFC used in the present invention is obtained by chemically modifying cellulosic pulp (CP) into chemically modified CP, followed by defibrillation and microfibrillation, or by chemically modifying the MFC. (see below for manufacturing method).

Substituent (R)
The substituent R in the above formula (1) (Lg)Cell-OR is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH (carboxyalkyl group), -CO(CH ₂ ) _n COOH (carboxyalkylcarbonyl group), -COCH=CHCOOH (3-carboxypropenoyl group), -( _CH2 ) _n-1 COO ^- X ⁺ (carboxyalkyl group salt), -CO( _CH2 ) _nCOO ^- X ⁺ (salt of carboxyalkylcarbonyl group) and -COCH=CHCOO ^- X ⁺ (salt of 3-carboxypropenoyl group) are preferably one or more selected from the group.

Said n is an integer of 2-4.

The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state.

As the substituent R, an acyl group having 2 to 3 carbon atoms (acetyl group and propionyl group) is more preferable.

As the substituent R, an acetyl group is most preferable in terms of ease of production and production cost.

As the substituent R having a carboxy group, _-CH2COOH (carboxymethyl group), -( _CH2 ) _2COOH (carboxyethyl group), -CO( _CH2 ) _2COOH (3-carboxypropionyl group, carboxyethylcarbonyl -CO(CH ₂ ) ₃ COOH (also referred to as 4-carboxybutanoyl group and carboxypropylcarbonyl group), -COCH=CHCOOH (also referred to as 3-carboxypropenoyl group and carboxyvinylcarbonyl group). ), and salts thereof are more preferred.

The salts thereof described above include salts of carboxymethyl groups, salts of carboxyethyl groups, salts of carboxyethylcarbonyl groups, salts of carboxypropylcarbonyl groups, salts of carboxyvinylcarbonyl groups, and the like.

As the substituent R having a carboxy group, -CH ₂ COOH (carboxymethyl group), -CO(CH ₂ ) ₂ COOH (also referred to as 3-carboxypropionyl group and carboxyethylcarbonyl group), -COCH=CHCOOH (3- Also referred to as a carboxypropenoyl group or a carboxyvinylcarbonyl group.) and salts thereof are most preferred.

It is also preferable that the carboxy groups of the substituent R having the carboxy group are groups (-COO ^- X ⁺ ) in the form of inorganic or organic salts.

Preferred examples of the inorganic salt include alkali metal salts such as sodium salts, lithium salts and potassium salts; divalent metal salts such as calcium salts, barium salts, zinc salts and copper salts; and trivalent metal salts such as aluminum salts. .

Primary to quaternary ammonium salts and salts with polyamines are also preferred as the organic salts.

Chemically modified MFCs having the various substituents described above are preferable because they have good dispersibility in fiber-reinforced resin compositions.

Two types of chemically modified MFCs with different substituents R can be combined (used together) and contained in the fiber-reinforced resin composition of the present invention.

For example, microfibrillated cellulose fibers in which R is an acetyl group (acetyl MFC), microfibrillated cellulose fibers in which R is a carboxymethyl group (carboxymethyl MFC), and microfibrillated cellulose fibers in which R is a 3-carboxypropionyl group ( 3-carboxypropionyl MFC) or 3-carboxypropenoyl group microfibrillated cellulosic fibers (3-carboxypropenoyl MFC) are preferably used in combination.

By using two chemically modified MFCs with different substituents R in combination, these chemically modified MFCs can be well dispersed in the fiber-reinforced resin composition.

Raw Material of Chemically Modified MFC As the raw material of the chemically modified MFC used in the present invention, pulp obtained from natural plants such as wood, bamboo, hemp, jute, kenaf, cotton, beet, agricultural waste, waste paper or textile fabric is preferably used. be done.

Pulp is obtained by separating vegetable fibers contained in plants such as wood, bamboo, and rice straw, and includes cellulose, hemicellulose, holocellulose and/or lignocellulose.

As the pulp raw material wood, for example, wood derived from coniferous or broad-leaved trees such as Sitka spruce, pine (Todomatsu, Japanese red pine, etc.), cedar, cypress, eucalyptus, acacia, etc. is preferably used. Waste paper used as a raw material for pulp is preferably deinked waste paper, corrugated waste paper, magazines, copier paper, and the like. Pulp raw materials are not limited to these. One type of pulp may be used alone, or two or more types selected from these may be used.

Pulp, which is a raw material for the chemically modified MFC used in the present invention, can be either lignin-free pulp or lignin-containing pulp (ie, lignocellulose-containing pulp).

It is preferable to use pulp containing lignin (that is, pulp containing lignocellulose) as the raw material of the chemically modified MFC used in the present invention. That is, (Lg)Cell- in formula (1) of the above (a) requirement is preferably a residue obtained by removing hydroxyl groups from polysaccharides and lignin constituting lignocellulose.

Lignocellulose is a complex hydrocarbon polymer (natural polymer mixture) that makes up the cell walls of trees. It is known that lignocellulose is mainly composed of polysaccharides cellulose, hemicellulose, and aromatic polymer lignin (see Reference Examples 1 and 2 below).

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

As used herein, the term "lignocellulose" means lignocellulose of chemical structure that occurs naturally in plants, artificially modified lignocellulose, or mixtures thereof. It is contained in various pulps obtained by mechanical and/or chemical treatment of plants such as wood, lignocellulose with a natural chemical structure, lignocellulose that has been chemically or mechanically modified, or A mixture of these.

The lignocellulose fibers used in the present invention are not limited to naturally occurring lignocellulose fibers with chemical structures. Also, the lignin content in the lignocellulose is not limited. The terms lignocellulose and lignopulp as used in the present invention are to be understood as lignocellulose and lignopulp respectively, even if the content of the lignin component is minor.

Raw materials for chemically modified MFC include toka spruce, pine (Todomatsu, Japanese red pine, etc.), cedar, cypress, eucalyptus, wood derived from broadleaf trees such as coniferous trees, bamboo, hemp, jute, kenaf, bagasse, straw, and beet pomace. Ligno pulp obtained by processing raw materials derived from vegetable raw materials contained in such as mechanical pulping, chemical pulping, or a combination of mechanical pulping and chemical pulping can be used.

As such pulp, various kraft pulps (softwood unbleached kraft pulp (NUKP), softwood oxygen bleached kraft pulp (NOKP), and softwood bleached kraft pulp (NBKP)) are preferred. Also preferred are mechanical pulps (MP) such as groundwood pulp (GP), refiner GP (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP) and the like.

Although some kraft pulps do not contain lignin, they can be used as raw materials for chemically modified MFC regardless of their content.

Among these, pulp containing lignin (lignopulp) has fewer manufacturing steps than cellulose fiber or pulp that does not contain lignin, and has a good yield from its raw material (for example, wood). It is advantageous in terms of manufacturing costs because it requires less chemical agents and can be manufactured with less energy. Thus, lignopulp can be advantageously used in the present invention.

Furthermore, among softwood pulps, lignopulp obtained from Sakhalin fir, Japanese red pine, or cedar can be used to obtain a fiber-reinforced resin composition having excellent strength characteristics by incorporating chemically modified lignoMFC produced using it. Therefore, it is preferable.

The amount of lignin in lignocellulose and lignopulp can be quantified by the Clason method. In the present invention, it is preferable to use lignopulp containing about 0.1 to 40% by mass of lignin. The lignin content of the lignopulp is more preferably about 0.1 to 35% by mass, particularly preferably about 0.1 to 30% by mass.

Method for producing chemically modified MFC The chemically modified MFC used in the present invention is obtained by chemically modifying cellulose pulp (CP) to obtain chemically modified cellulose pulp (chemically modified CP) and defibrating it. .

The chemically modified MFC used in the present invention can also be obtained by defibrating cellulosic pulp (CP) to obtain microfibrillated plant fibers (MFC) and chemically modifying this.

First, a method of chemically modifying cellulose pulp (CP) to obtain chemically modified cellulose pulp (chemically modified CP) will be described. A method for defibrating cellulose pulp (CP) or chemically modified CP will be described later.

Manufacturing method of chemically modified cellulose pulp (chemically modified CP)
Acylated Cellulosic Pulp (Acylated CP)
Of the chemically modified pulp composed of the chemically modified cellulose polymer represented by the formula: (Lg)Cell-OR (1), the pulp composed of the chemically modified cellulose polymer in which the substituent R is an acyl group (acylated CP ) can be obtained by acylating hydroxyl groups (hydroxyl groups of cellulose, hemicellulose, lignin, etc.) present on the fiber surface or amorphous portion of the cellulose pulp (CP) raw material.

This acylation acylates hydroxyl groups present on the fiber surface or amorphous portion of CP, such as hydroxyl groups of cellulose, hemicellulose, and lignin, so as not to destroy the cellulose crystal structure originally present in the raw material CP. is preferred.

The acylation reaction is carried out by suspending the raw material in an anhydrous aprotic polar solvent such as N-methylpyrrolidone, N,N-dimethylformamide, etc., which can swell the CP of the raw material, and obtaining a carboxylic acid having a corresponding acyl group. It can be carried out by a conventional method (method described in JP-A-2016-176052, etc.) in the presence of a base with an anhydride or an acid chloride.

A method for measuring the degree of substitution by R (described in detail below) in formula (1) can follow a conventional method (method described in JP-A-2016-176052, etc.). The degree of substitution can be adjusted by adjusting the amount of acylating agent, reaction temperature, reaction time, etc. in the above acylation.

Carboxyalkylated Cellulosic Pulp (Carboxyalkylated CP)
chemical modification wherein R is a carboxyalkyl group [-(CH ₂ ) _n-1 COOH] or a salt thereof [-(CH ₂ ) _n-1 COO ^- X ⁺ ] in the above formula: (Lg)Cell-OR (1) Cellulosic pulp (carboxyalkylated CP) can be produced according to a conventional method (method described in JP-A-2011-195738, etc.). That is, the raw material CP is reacted with the corresponding alkyl halide to carboxyalkylate hydroxyl groups present on the fiber surface or amorphous portion of the raw material fiber (CP) (hydroxyl groups of cellulose, hemicellulose, lignin, etc.). Carboxyalkylated CPs can be prepared.

Carboxyalkylcarbonylated Cellulosic Pulp (Carboxyalkylcarbonylated CP)
Chemically modified cellulose in which R is a carboxyalkylcarbonyl group [-CO( _CH2 ) _nCOOH ] or a salt thereof [-CO( _CH2 ) _nCOO ^- X ⁺ ] in the above formula: (Lg)Cell-OR (1) System pulp (carboxyalkylcarbonylated CP) can be produced according to the method described in the literature (Biomacromolecules 2017, 18, 242-248). That is, the carboxyalkylcarbonylated CP can be produced by reacting the starting CP with the corresponding acid anhydride (eg, succinic anhydride, glutaric anhydride, etc.).

3-Carboxypropenoylated Cellulosic Pulp (3-Carboxypropenoylated CP, maleic acid monoester of CP)
^Chemically modified cellulose ^pulp (3-carboxy Propenoylated CP) can be produced according to the method described in the literature (ACS Macro Lett. 2015, 4, 80-83). That is, 3-carboxypropenoylated CP can be produced by reacting maleic anhydride with CP as a raw material.

In addition, when chemically modifying microfibrillated cellulose (MFC) to produce a chemically modified MFC, MFC is used instead of cellulose pulp (CP), and the MFC is chemically modified in the same manner as above. A chemically modified MFC can be obtained by

Degree of modification by substituent R (degree of substitution, DS)
The degree of modification (degree of substitution, also referred to as “DS”) of the chemically modified CP or chemically modified MFC by the substituent R is determined by the residue of the chemically modified cellulosic polymer represented by the above formula (1) [(Lg)Cell- ] is substituted with the substituent R for the hydrogen atom of the hydroxyl group present in one unit (repeating unit).

When the chemically modified cellulosic polymer is entirely composed of cellulose (in the case of cellulose), this repeating unit is a glucopyranose residue, and the number of hydroxyl groups per unit is 3, so the upper limit of the degree of substitution is is 3.

On the other hand, when the cellulosic polymer is lignocellulose, lignocellulose contains hemicellulose and lignin together with cellulose. The xylose residue in xylan contained in hemicellulose or the galactose residue in arabinogalactan has two hydroxyl groups, and the standard lignin residue also has two hydroxyl groups. Therefore, their number of hydroxyl groups is less than three.

Therefore, the upper limit of the degree of substitution by substituents R in lignopulp is less than three. The upper limit of this degree of substitution is about 2.7 to 2.8, depending on the content of hemicellulose and lignin contained in the lignopulp.

Also, when the cellulosic polymer is holocellulose, since holocellulose contains hemicellulose together with cellulose, the average number of hydroxyl groups in the repeating unit is less than 3. Therefore, the upper limit of the degree of substitution is less than 3.

Although it depends on the content of hemicellulose or lignin in the cellulosic fiber as described above, the chemically modified cellulosic pulp (chemically modified CP) and the chemically modified microfibrillated cellulosic fiber (chemically modified MFC) by the substituent R The degree of substitution (DS) is preferably about 0.3-2.55. By setting the degree of substitution (DS) to about 0.3 to 2.55, a chemically modified MFC with moderate crystallinity and SP (solubility parameter) can be obtained.

When the substituent R is an acyl group, the degree of substitution (DS) is more preferably about 0.4-2.55, more preferably 0.56-2.52. When the substituent R is an acetyl group, the preferred DS is 0.56-2.52. If the DS is in that range, it is possible to keep the degree of crystallinity at about 42.7% or more.

When the substituent R is a carboxyalkyl group, a carboxyalkylcarbonyl group, a 3-carboxypropenoyl group, or a salt of a substituent having these carboxy groups, the degree of substitution (DS) is DS when R is an acyl group. is preferably smaller than When the substituent R is a carboxymethyl group, DS is preferably 0.1 to 0.5.

The degree of substitution (DS) can be analyzed by various analytical methods such as elemental analysis, neutralization titration, FT-IR, and two-dimensional NMR ( ¹ H and ¹³ C-NMR).

Defibrillation method of chemically modified CP Defibrillation and microfibrillation of chemically modified CP are carried out, for example, by making chemically modified CP into a suspension or slurry, refiner, high-pressure homogenizer, grinder, single-screw or multi-screw kneader (preferably twin-screw). kneader), bead mill or the like, or use known means such as mechanical grinding or beating.

When the chemically modified CP is used to produce the fiber-reinforced resin composition of the present invention, the chemically modified CP is melted and kneaded under heating in a single- or multi-screw kneader (preferably a multi-screw kneader) together with the thermoplastic resin. preferably. The chemically modified CP is fibrillated by the shear force during kneading to be microfibrillated, and can be made into the chemically modified MFC in the thermoplastic resin. It is advantageous to melt-knead the chemically modified CP with the thermoplastic resin in this manner and defibrate in the thermoplastic resin.

When chemically modified MFC is used to produce the fiber-reinforced resin composition of the present invention, the fibers of CP are first defibrated to prepare microfibrillated cellulosic fibers (MFC). Then, the fiber-reinforced resin composition of the present invention can be prepared by chemically modifying this by the method described above and kneading it with a resin.

In this case, the defibration of CP is performed by making CP into a suspension or slurry, and mechanically grinding or beating the CP using a refiner, a high-pressure homogenizer, a grinder, a uniaxial or multiaxial kneader (preferably a twin-screw kneader), a bead mill, or the like. It can be performed by using known means such as.

Fiber Diameter of MFC and Chemically Modified MFC Chemically modified MFC is obtained by disentangling (fibrillating) the fibers in the chemically modified cellulose pulp (for example, chemically modified lignopulp, etc.) to the nano-size level.

The average fiber diameter (fiber width) of the chemically modified MFC contained in the fiber-reinforced resin composition is preferably in the range of about 4-200 nm, more preferably about 4-150 nm. The average fiber length is preferably about 5 μm or more.

By incorporating a chemically modified MFC having an average fiber diameter within the above range into a resin, a fiber-reinforced resin composition having excellent strength properties can be produced.

When the fiber-reinforced resin composition of the present invention is produced using the chemically modified CP, the chemically modified CP is melt-kneaded with the thermoplastic resin, and simultaneously kneaded, the chemically modified CP is defibrated into the chemically modified MFC. be able to.

In this case, even if the disentanglement of the chemically modified CP is insufficient and the resin composition contains the chemically modified MFC having a fiber diameter larger than the fiber diameter after disentanglement, the object of the present invention can be achieved. To the extent such chemically modified MFC-containing resin compositions are included in the present invention.

For example, as long as the flexural modulus of the chemically modified MFC-containing resin composition exhibits a flexural modulus of 1.1 times or more that of the unmodified MFC-containing resin composition, this is the chemically modified MFC-containing resin composition of the present invention. It is a thing.

When chemically modified MFC is prepared using MFC, the respective preferred ranges and more preferred ranges of the average fiber diameter and average fiber length of this MFC are the same as those of the above chemically modified MFC.

The fiber diameter and fiber length of MFC and chemically modified MFC can be measured using a scanning electron microscope (SEM). The average fiber diameter (average fiber diameter) and average fiber length (average fiber length) are obtained as the average values of at least 50 MFCs or chemically modified MFCs within the field of view of the scanning electron microscope. .

By observing the fibers with a scanning electron microscope (SEM) of the specific surface area of MFC and chemically modified MFC , it is possible to observe the disentanglement state of the fibers.

The specific surface area of the chemically modified MFC is preferably about 70-300 m ² /g, more preferably about 70-250 m ² /g, even more preferably about 100-200 m ² /g. By increasing the specific surface area of the chemically modified MFC, it is possible to increase the contact area when combined with a resin (matrix) to form a composition, thereby improving the strength of the resin molding material. Moreover, since the chemically modified MFC does not aggregate in the resin of the resin composition, the strength of the resin molding material can be improved.

Crystallinity of Chemically Modified MFC The chemically modified MFC used in the present invention retains the crystal structure of the cellulose present in the raw pulp as much as possible, and the hydroxyl groups of the cellulose and hemicellulose of the raw pulp (CP) ( Sugar chain hydroxyl groups) are preferably chemically modified.

In the chemically modified MFC used in the present invention, the hydroxyl groups present on the surface of the raw material fiber, such as the hydroxyl groups of cellulose and the hydroxyl groups of hemicellulose, are originally chemically modified so that the cellulose crystal structure present in the raw material pulp is not destroyed. is preferred.

Through the chemical modification treatment, a chemically modified MFC having excellent mechanical properties inherent to MFC can be obtained. Furthermore, the dispersibility of the chemically modified MFC in the resin is promoted, and the reinforcing effect of the chemically modified MFC on the resin is improved.

In the fiber-reinforced resin composition of the present invention, the chemically modified MFC contained in the composition preferably has a degree of crystallinity of about 42.7% or more, and preferably has cellulose type I crystals. The "crystallinity" is the abundance ratio of crystals (mainly cellulose type I crystals) in the total cellulose. The crystallinity of the chemically modified MFC (preferably cellulose type I crystals) is preferably about 50% or higher, more preferably about 55% or higher, even more preferably about 55.6% or higher, and even more preferably about 60% or higher. About 69.5% or more is particularly preferable.

The upper limit of the crystallinity of chemically modified MFC is about 80%. Chemically modified MFC maintains the crystalline structure of cellulose type I and exhibits performance such as high strength and low thermal expansion.

The cellulose type I crystal structure is, for example, as described in "The Dictionary of Cellulose" published by Asakura Shoten, pp. 81-86 or pp. 93-99 of the first edition of the new edition. Most natural celluloses are of the cellulose type I crystal structure. In contrast, cellulose fibers of, for example, cellulose II, III, or IV structure, but not cellulose type I crystalline structure, are derived from cellulose having cellulose type I crystalline structure. The I-type crystal structure has a higher crystal elastic modulus than other structures.

The fact that the chemically modified MFC has a type I crystal structure is typical for two positions near 2θ = 14 to 17° and 2θ = 22 to 23° in the diffraction profile obtained by wide-angle X-ray diffraction image measurement. It can be determined from having a peak.

Cellulose consists of several bundles of cellulose elongated linearly by β-1,4 bonds, which are fixed by intramolecular or intermolecular hydrogen bonds to form extended chain crystals. .

Analysis by X-ray diffraction or solid-state NMR has revealed that cellulose crystals have many crystal forms. The only crystalline form of natural cellulose is type I.

From X-ray diffraction and the like, it is estimated that the ratio of crystalline regions in cellulose is about 50 to 60% in wood pulp, and about 70% in bacterial cellulose, which is higher than this. Due to its extended chain crystals, cellulose not only has a high elastic modulus, but also exhibits a strength five times that of steel and a linear thermal expansion coefficient of 1/50 or less that of glass.

(1-2) (B) Inorganic filler The (B) inorganic filler contained in the fiber-reinforced resin composition of the present invention includes glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and One or two or more inorganic fillers selected from the group consisting of nanoclays.

The inorganic filler is preferably one or more fibrous inorganic fillers selected from the group consisting of glass fiber, glass wool and carbon fiber. Furthermore, one or two fibrous inorganic fillers selected from the group consisting of glass fibers and carbon fibers are preferred.

Glass fibers and glass wool are preferably chemically modified on the surface in order to have affinity with the resin in the fiber-reinforced resin composition of the present invention.

Commercially available glass fibers can be used. As the glass fiber, for example, CSX3J, CSF3PE manufactured by Nitto Boseki Co., Ltd., and the like can be preferably used.

The average fiber diameter of the glass fibers is preferably about 9-15 μm, more preferably about 11-13 μm. The average fiber length of glass fibers is preferably about 3 to 10 mm.

As the glass wool, commercially available ones can be used. As the glass wool, for example, white wool manufactured by Asahi Fiber Glass Co., Ltd. can be preferably used.

The average fiber diameter of the glass wool is preferably about 5-10 μm, more preferably about 7-8 μm. The average fiber length of glass wool is preferably about 20 to 100 mm.

Carbon fibers are preferably surface-treated in order to have affinity with the resin in the fiber-reinforced resin composition of the present invention.

Commercially available carbon fibers can be used. As the carbon fiber, for example, Torayca (registered trademark) manufactured by Toray Industries, Inc., Tenax (registered trademark) manufactured by Toho Tenax Co., Ltd., and the like can be preferably used.

The average fiber diameter of the carbon fibers is preferably about 5-18 μm, more preferably about 5-7 μm. The average fiber length of carbon fibers is preferably about 3 to 25 mm.

(1-3) (C) Thermoplastic resin The fiber-reinforced resin composition of the present invention contains (A) a chemically modified MFC, (B) an inorganic filler and (C) a thermoplastic resin. By using this fiber-reinforced resin composition, a molded article having excellent strength can be produced.

(C) As thermoplastic resins, polyamides, polyolefins, aliphatic polyesters, aromatic polyesters, polyacetals, polycarbonates, polystyrenes, acrylonitrile-butadiene-styrene co- It is preferable to use at least one resin selected from the group consisting of polymers (ABS resin), polycarbonate-ABS alloys (PC-ABS alloys), and modified polyphenylene ethers (m-PPE).

As the thermoplastic resin, the above resins may be used alone, or two or more of them may be used as a mixed resin.

Resins other than the above, such as polyvinyl chloride, polyvinylidene chloride, fluororesin, (meth)acrylic resin, (thermoplastic) polyurethane, vinyl ether resin, polysulfone resin, cellulose resin (e.g., triacetylated cellulose , diacetylated cellulose, etc.) can also be preferably used.

Polyamide (PA) includes polyamide 6 (nylon 6, PA6), polyamide 66 (nylon 66, PA66), polyamide 610 (PA610), polyamide 612 (PA612), polyamide 11 (PA11), polyamide 12 (PA12), polyamide 46 , polyamide XD10 (PAXD10), polyamide MXD6 (PAMXD6) and the like can be preferably used.

As the polyolefin, polypropylene (PP), a copolymer of polyethylene (PE) and polypropylene (PP), maleic anhydride-modified polypropylene (MAPP), polyethylene (PE, especially high-density polyethylene HDPE), etc. can be preferably used. .

Isotactic polypropylene (iPP), syndiotactic polypropylene (sPP) and the like can be preferably used as the polypropylene (PP).

As aliphatic polyesters, polymers or copolymers of diols and aliphatic dicarboxylic acids such as succinic acid and valeric acid (e.g., polybutylene succinate (PBS)), hydroxycarboxylic acids such as glycolic acid and lactic acid alone Polymers or copolymers (eg, polylactic acid, poly ε-caprolactone (PCL), etc.), copolymers of diols, aliphatic dicarboxylic acids and the above hydroxycarboxylic acids, etc. can be preferably used.

As aromatic polyesters, polymers of diols such as ethylene glycol, propylene glycol and 1,4-butanediol and aromatic dicarboxylic acids such as terephthalic acid can be preferably used. Specifically, for example, polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), etc. can be preferably used.

As polyacetal (also referred to as polyoxymethylene, POM), in addition to homopolymers of paraformaldehyde, copolymers of paraformaldehyde and oxyethylene can also be preferably used.

For polycarbonate (PC), a reaction product of bisphenol A or a bisphenol derivative thereof and phosgene or phenyldicarbonate can be preferably used.

As polystyrene (PS), in addition to general-purpose PS (GPPS), PS (HIPS) in which a rubber component is dispersed in a PS matrix to improve impact resistance can be preferably used. In addition to polystyrene (PS), styrene copolymers (acrylonitrile-butadiene-styrene copolymers, ABS resins) are preferred resins for the matrix of the fiber-reinforced resin composition of the present invention.

A blend of polycarbonate (PC) and ABS (PC-ABS alloy) is preferred because it is excellent in impact resistance, weather resistance and moldability.

A blended product of PPE and PS (PPE-PS blended product) is a type of modified polyphenylene ether (PPE) (m-PPE). PPE-PS blend products are preferred because they have high heat resistance and are lightweight.

Among thermoplastic resins, PA, POM, PP, MAPP, PE, polylactic acid, lactic acid copolymer resin, PBS, PET, PPT, PBT, It is preferable to use at least one resin selected from the group consisting of PS, ABS resin and PC-ABS alloy.

(2) Composition of fiber-reinforced resin composition The fiber-reinforced resin composition of the present invention contains (A) chemically modified MFC, (B) inorganic filler and (C) thermoplastic resin.

The content of (A) the chemically modified MFC in the fiber-reinforced resin composition of the present invention is preferably about 3 to 60 parts by mass, more preferably about 5 to 50 parts by mass, relative to 100 parts by mass of the (C) thermoplastic resin. Preferably, about 5 to 40 parts by mass is more preferable. Most preferably, the content of (A) the chemically modified MFC in the fiber-reinforced resin composition is about 5 to 30 parts by mass.

(A) As chemically modified MFC, acetylated MFC is preferred.

The content of the (B) inorganic filler in the fiber-reinforced resin composition of the present invention is preferably about 3 to 60 parts by mass, more preferably about 5 to 50 parts by mass, relative to 100 parts by mass of the (C) thermoplastic resin. , and more preferably about 5 to 40 parts by mass. The content of (B) the inorganic filler (preferably glass fiber or carbon fiber) in the fiber-reinforced resin composition is most preferably about 5 to 30 parts by mass.

(B) The inorganic filler is preferably glass fiber and/or carbon fiber.

The mass ratio of (A) chemically modified MFC to (B) inorganic filler in the fiber-reinforced resin composition of the present invention is 0.25-4, preferably 0.3-3, more preferably 0.5-2. In other words, the mass ratio of (A) the amount of chemically modified MFC/(B) the amount of inorganic filler is 0.25 to 4, preferably 0.3 to 3, more preferably 0.5 to 2.

By blending (A) the chemically modified MFC with (C) the thermoplastic resin, it is possible to obtain a fiber-reinforced resin composition excellent in mechanical properties, heat resistance, surface smoothness and appearance.

By blending (A) chemically modified MFC with (B) inorganic filler into (C) thermoplastic resin, fiber reinforced resin that is lighter and has superior mechanical properties compared to blending (B) inorganic filler alone. A composition can be obtained.

(A) The chemically modified MFC is lightweight, has excellent strength, and has a low coefficient of linear thermal expansion, similar to plant fibers.

The fiber-reinforced resin composition of the present invention, even if it contains (A) a chemically modified MFC and (B) an inorganic filler, softens when heated and is easy to mold, like general-purpose plastics. You can express your sexuality.

In addition to (A) the chemically modified MFC, (B) the inorganic filler and (C) the thermoplastic resin, the fiber-reinforced resin composition of the present invention includes, for example, a compatibilizer; a surfactant; an antioxidant; Inorganic compounds such as tannins, zeolites, ceramics, metal powders; Colorants; Plasticizers; may optionally be added.

The content of the additive can be appropriately adjusted within a range that does not impair the effects of the present invention.

Since the fiber-reinforced resin composition of the present invention contains (A) chemically modified CMF, self-aggregation of the fibers due to hydrogen bonding can be suppressed. Therefore, even if (A) chemically modified MFC, (B) inorganic filler, and (C) thermoplastic resin are mixed, aggregation between (A) chemically modified MFCs is suppressed, and (A) chemically modified MFC and (B) The inorganic filler (C) exhibits good dispersibility in the thermoplastic resin. As a result, the fiber-reinforced resin composition of the present invention is excellent in mechanical properties, heat resistance, surface smoothness and appearance.

In the fiber-reinforced resin composition of the present invention, (A) the chemically modified MFC preferably has a solubility parameter (SP) close to the SP of (C) the thermoplastic resin.

(C) When a highly polar resin is used as the thermoplastic resin to form the matrix of the fiber reinforced resin composition, when the substituent R is, for example, an acetyl group, the degree of substitution (DS) is about 0.4 to 1.2. It is preferable to incorporate acetylated MFC having a solubility parameter of about 12-15 into the resin.

As highly polar resins, for example, PA, POM, polylactic acid, and the like are preferable.

(C) When a resin with low polarity is used as a thermoplastic resin and used as a matrix for a fiber reinforced resin composition, a chemically modified MFC having a degree of substitution (DS) of about 1.2 or more and a solubility parameter of about 8 to 12 is used. It is preferably contained in the resin.

PP, PE, and the like are preferable as resins with low polarity, for example. Acetylated MFC is preferred as the chemically modified MFC.

(3) Manufacturing method of fiber reinforced resin composition
Manufacturing method 1
The fiber-reinforced resin composition of the present invention is prepared by melt-kneading (A) a chemically modified MFC, (B) an inorganic filler, and (C) a thermoplastic resin (matrix material), (A) a chemically modified MFC and (B) an inorganic It can be produced by dispersing the filler in (C) the thermoplastic resin.

By molding the fiber-reinforced resin composition, a molded body of the fiber-reinforced resin composition can be produced.

Process 2
The fiber-reinforced resin composition of the present invention uses a kneader or the like to knead the chemically modified cellulose pulp (chemically modified CP), (B) the inorganic filler, and (C) the thermoplastic resin at once, and combine them. It is preferable to manufacture by converting. That is, production method 2 is a method of simultaneously melt-kneading the chemically modified cellulose pulp, the inorganic filler, and the thermoplastic resin.

Production method 2 is a method for producing a fiber-reinforced resin composition,
(i) Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
A chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by
(ii) (B) inorganic filler, and (iii) (C) thermoplastic resin are melt-kneaded to obtain (A) chemically modified microfibrillated cellulosic fiber, (B) inorganic filler, and (C) thermoplastic resin. wherein the (A) chemically modified microfibrillated cellulose fiber and the (B) inorganic filler meet the requirements of the following (a) and (b): fiber reinforced resin A method for producing a composition.
(a) (A) Chemically modified microfibrillated cellulosic fibers are represented by the following formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

In production method 2, fibrillation of the chemically modified CP proceeds satisfactorily due to the shear stress during kneading. During kneading, the chemically modified CP is successfully defibrated into (A) the chemically modified MFC in the resin. According to production method 2, a fiber-reinforced resin composition can be produced in which (A) the chemically modified MFC and (B) the inorganic filler are well dispersed in the (C) thermoplastic resin.

Process 3
The fiber-reinforced resin composition of the present invention is obtained by kneading a chemically modified cellulose pulp (chemically modified CP) and (C) a thermoplastic resin to obtain a kneaded product, and then the obtained kneaded product and (B) an inorganic It is preferably manufactured by a method of melt-kneading a resin composition containing a filler and a thermoplastic resin. Production method 3 is a method of melt-kneading chemically modified cellulose pulp and a thermoplastic resin, then adding a resin composition containing an inorganic filler and melt-kneading, that is, a method of kneading in two steps.

Production method 3 is a method for producing a fiber-reinforced resin composition,
Process (1):
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
Chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by and (C) a step of kneading a thermoplastic resin, and
Step (2):
(A) a chemically modified microfibrillated cellulose fiber by a method comprising a step of melt-kneading the kneaded product obtained in the step (1) and (B) a resin composition containing an inorganic filler and a thermoplastic resin; , (B) an inorganic filler and (C) a method for producing a fiber-reinforced resin composition containing a thermoplastic resin,
In the method for producing a fiber-reinforced resin composition, the (A) chemically modified microfibrillated cellulose fibers and the (B) inorganic filler satisfy the following requirements (a) and (b).
(a) (A) Chemically modified microfibrillated cellulosic fibers are represented by the following formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, -CO(CH ₂ ) _n COOH, -COCH=CHCOOH, -(CH ₂ ) _n-1 COO ^- X ⁺ , -CO(CH ₂ ) _n COO ^- X ⁺ and -COCH=CHCOO ^- X ⁺ , wherein n is an integer of 2-4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay.

In production method 3, fibrillation of the chemically modified CP proceeds satisfactorily due to the shear stress during kneading. During kneading, the chemically modified CP is successfully defibrated into (A) the chemically modified MFC in the resin. According to production method 3, a fiber-reinforced resin composition can be produced in which (A) the chemically modified MFC and (B) the inorganic filler are well dispersed in the (C) thermoplastic resin.

As the resin composition containing an inorganic filler and a thermoplastic resin used in production method 3, (I) a molten mixture of (a) an inorganic filler and (b) a thermoplastic resin (a commercially available product may be used), and (II) powder mixtures of (a) inorganic fillers and (b) thermoplastic resins can also be used.

The heating setting temperature during melt kneading in each manufacturing method is from the minimum processing temperature (A ° C) recommended by the supplier of the thermoplastic resin used in the present invention to a temperature 20 ° C higher than this recommended processing temperature (A + 20 °C) is preferred.

When PA6 is used, the heating setting temperature during melt-kneading is preferably 225 to 240°C.

When POM is used, the heating setting temperature during melt-kneading is preferably 170 to 190°C.

When PP and MAPP are used, the heating setting temperature during melt-kneading is preferably 160 to 180°C.

By setting the mixing temperature within this temperature range, (A) the chemically modified MFC or chemically modified pulp, (B) the inorganic filler, and (C) the thermoplastic resin can be uniformly mixed.

Among the above production methods, production method 2 and production method 3 allow the production cost to be reduced because unfibrillated chemically modified CP is mixed with resin and fibrillated by the shear stress of the kneader. In addition, according to production methods 2 and 3, chemically modified MFC with less fiber damage can be prepared from chemically modified CP in a state of being dispersed in a thermoplastic resin.

According to production method 2 and production method 3, it is possible to obtain a high-performance fiber-reinforced resin composition in which this chemically modified MFC is dispersed.

(4) Molded article of fiber-reinforced resin composition The molded article of the present invention is made of a fiber-reinforced resin composition.

A molded article can be produced using the fiber-reinforced resin composition of the present invention.

If necessary, the fiber-reinforced resin composition of the present invention is shaped into a film, sheet, plate, pellet, powder, or the like to prepare a molding material, and the molding material is used to manufacture a molded product. can be provided to

The fiber-reinforced resin composition (molding material) of the present invention is molded by various known molding methods such as mold molding, injection molding, extrusion molding, hollow molding, foam molding, etc., to obtain a plate shape, rod shape, three-dimensional structure, etc. Molded bodies of various shapes can be produced.

Since the molded article of the present invention is molded from a fiber-reinforced resin composition containing (A) a chemically modified MFC, (B) an inorganic filler, and (C) a thermoplastic resin, only inorganic fibers such as glass fibers and carbon fibers It is lighter and has excellent strength characteristics as compared with a molded article molded from a fiber reinforced resin composition containing.

By using the molded article of the present invention for interior materials, exterior materials, structural materials, etc. of transportation equipment such as automobiles, trains, ships, and airplanes, it is possible to improve the energy efficiency of transportation equipment and reduce exhaust gas. can.

By using the molded article of the present invention for housings, structural materials, internal parts, etc. of electrical appliances such as personal computers, televisions, and telephones, weight reduction can be achieved. Lighter weight can reduce energy consumption during transport of these appliances and also make the appliances more comfortable to use.

By using the molded article of the present invention as a building material, it is possible to improve the earthquake resistance of buildings.

EXAMPLES The present invention will now be described in more detail with reference to examples and comparative examples.

The invention is not limited to these examples.

In the examples, the contents of various components in pulp, chemically modified pulp, chemically modified MFC, thermoplastic resin, etc. are expressed in % by mass unless otherwise specified.

In this specification, the content of cellulosic fibers in the composition is indicated by the mass ratio of the fiber component (cellulose + hemicellulose) in the total mass of the composition. Therefore, the content ratio of the chemically modified cellulosic fibers in the composition is indicated by the content ratio (content %) of the mass in terms of the non-chemically modified fibers.

I. Test Methods The test methods used in Examples and Comparative Examples are as follows.

(1) Lignin determination method (Clason method)
A glass fiber filter paper (GA55) was dried in an oven at 110° C. to a constant weight, allowed to cool in a desiccator, and weighed. A sample (approximately 0.2 g) dried at 110° C. was precisely weighed and placed in a 50 mL tube.

3 mL of 72% concentrated sulfuric acid was added, and the tube was placed in hot water at 30°C and kept warm for 1 hour while crushing appropriately with a glass rod so that the contents were uniform. Then, the contents of the tube and 84 g of distilled water were poured into an Erlenmeyer flask and mixed, and then reacted at 120° C. for 1 hour in an autoclave.

After allowing to cool, the contents were filtered through glass fiber filter paper to remove insoluble matter, which was washed with 200 mL of distilled water. It was dried in a 110°C oven to constant weight and weighed.

(2) Method for quantitative determination of cellulose and hemicellulose (sugar analysis)
A glass fiber filter paper (GA55) was dried in an oven at 110° C. to a constant weight, allowed to cool in a desiccator, and weighed. A sample (approximately 0.2 g) dried at 110° C. was precisely weighed and placed in a 50 mL tube.

3 mL of 72% concentrated sulfuric acid was added, and the tube was placed in hot water at 30°C and kept warm for 1 hour while crushing appropriately with a glass rod so that the contents were uniform. Next, the contents of the tube and 84 g of distilled water were added, and the mixture was poured quantitatively into an Erlenmeyer flask and mixed.

72% concentrated sulfuric acid (7.5 μL) was added using a graduated pipette and reacted at 120° C. for 1 hour in an autoclave.

After standing to cool, 100 μL of the reaction solution was diluted with ultrapure water and subjected to ion chromatograph analysis manufactured by Thermo Fisher Scientific to analyze sugar components contained in the sample.

(3) Method for measuring the degree of chemical modification (DS) of cellulose or hemicellulose hydroxyl groups
(3-1) Back titration method A method for measuring the DS of samples in which the hydroxyl groups of cellulose, hemicellulose and lignocellulose are acylated (esterified) will be described below taking acetylated samples as examples.

The same applies to other acylations.

Preparation, Weighing and Hydrolysis Samples were dried and weighed accurately to 0.5 g (A). 75 mL of ethanol and 50 mL of 0.5N NaOH (0.025 mol) (B) were added thereto and stirred for 3 to 4 hours.

This was filtered, washed with water and dried, and FT-IR measurement was performed on the sample on the filter paper, and it was confirmed that the absorption peak based on the carbonyl of the ester bond disappeared, that is, the ester bond was hydrolyzed. This filtrate was used for the following back titration.

The back titration filtrate contains sodium acetate resulting from hydrolysis and NaOH added in excess. This NaOH neutralization titration was performed with 1N HCl and phenolphthalein.

・0.025 mol (B) - (moles of HCl used for neutralization) = moles of acetyl groups ester-bonded to hydroxyl groups of cellulose (C)
・(Molecular weight of cellulose repeating unit 162 × number of moles of cellulose repeating unit (unknown (D))) + (molecular weight of acetyl group 43 × (C)) = 0.5 g (A) of weighed sample
The number of moles (D) of repeating units of cellulose is calculated.

DS is
・DS=(C)/(D)
Calculated by

(3-2) Method for measuring DS by infrared (IR) absorption spectrum DS of esterified cellulose/lignocellulose can also be determined by measuring infrared (IR) absorption spectrum.

When cellulose/lignocellulose is esterified, a strong absorption band derived from ester carbonyl (C=O) appears near 1733 cm ^-1 . First, create a calibration curve in which the DS values obtained by the method are plotted on the horizontal axis.

Then, the DS value of the sample is obtained by measuring the intensity of the absorption band and from this value and the calibration curve. In this way DS can be measured quickly and conveniently.

(4) Measurement of crystallinity of cellulose, etc. The method described in Wood Science Experiment Manual 4. Microstructure (1) Structural analysis by X-ray (P.198-202) was followed. Using a model Rigaku ultraX18HF (manufactured by Rigaku Co., Ltd.), wide-angle X-ray diffraction of a sample (refined pulp and its chemical modification) is measured to determine the crystallinity of the sample.

X-rays are CuKα rays, 30kV/200mA output, and measure 2θ=5 to 40°.

(5) Strength test method A three-point bending test was performed using a universal testing machine (Autograph AG5000E, manufactured by Shimadzu Corporation). The test conditions were a bending speed of 10 mm/min and a distance between fulcrums of 64 mm.

(6) Izod impact test
An Izod impact test was performed using an Izod impact tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). A notch with a depth of 2 mm was inserted in the center of the test piece. In the 2.75JN test, a 2.75J hammer was used to hit the notch side to propagate a crack from the notch, and its impact strength was calculated. In the 5.5JR test, a 5.5J hammer was used to hit the side opposite to the notch, allowing cracks to propagate from the surface of the molded article without notches, and the impact strength at that time was calculated.

(7) Method for measuring the viscosity of the resin composition A melt viscoelasticity measuring device (manufactured by TA Instruments) was used to measure the viscosity of the composition. The measurement conditions were a temperature of 250°C, a frequency of 628 rad/sec, and a strain of 0.05%.

(8) Microscopic observation of fibers (observation of fiber length and fiber diameter)
The fiber samples were observed with a field emission scanning electron microscope (FE-SEM), JSM-7800F manufactured by JEOL. The measurement conditions were an acceleration voltage of 1.5 kV and a magnification of 200 to 5000 times.
The sample preparation method is as follows.
1) Preparation of fiber samples before compounding with resin
1-1) The sample was placed in a glass vial containing ethanol and ultrasonically agitated to suspend the fibers in the ethanol.
1-2) A small amount of an ethanol suspension of fibers was dropped on a copper plate and the ethanol was allowed to evaporate at room temperature.
1-3) A sample was coated with platinum using a sputtering device (JEOL SEC-3000FC auto fine coater).
2) Microscopic observation of fibers in resin composite Taking CNF in a molded body of nylon 6 (PA6) composition (PA6/CNF = 90/10) containing cellulose nanofiber (CNF) as an example, the sample for microscopic observation A preparation method is explained.
2-1) A test piece of 4x2x1.2mm was cut out from the injection molded product.
2-2) The test piece was added to 400 ml of NMP and immersed at 190°C for 2 to 4 hours to elute PA6.
2-3) The residues (fibers) after PA6 elution were placed in a glass vial containing ethanol, and the fibers were suspended in ethanol by ultrasonic agitation. Thereafter, samples for microscopic observation were prepared according to 1-2) and 1-3) above.

II. Materials used
A. Raw material pulp
(1) Softwood-derived bleached kraft pulp (NBKP)
Softwood bleached kraft pulp (NBKP, source: Oji Holdings Co., Ltd.) slurry (water suspension with a pulp slurry concentration of 3% by mass) is passed through a single disc refiner (manufactured by Aikawa Iron Works Co., Ltd.), Canadian standard The fibrillation treatment was performed repeatedly by the refiner treatment until the freeness (CSF) value reached 50 mL.

Fibers were observed with a scanning electron microscope (SEM). Fibers with diameters on the order of submicrons were also observed, but fibers with coarse fiber diameters of several tens to several hundreds of micrometers in diameter were found here and there.

As a result of sugar analysis, the composition (% by mass) was as follows.

B. chemically modified pulp
(1) Acetylated NBKP (AcNBKP)
Water-containing NBKP (refined) was concentrated, N-methylpyrrolidone (NMP) was added, and dehydration was performed under reduced pressure while heating. Acetic anhydride (0.58 molar equivalents) and K ₂ CO ₃ (0.3 molar equivalents) were added to an NMP suspension of NBKP (solid content: 20%), and the mixture was heated and stirred at 80° C. for 90 minutes to react. After the reaction was completed, the mixture was concentrated and the solid was washed with water to obtain a slurry of acetylated NBKP (AcNBKP).

The degree of substitution (DS) of acetylation was calculated by adding an alkali to AcNBKP and titrating the amount of acetic acid generated by hydrolyzing the ester bond (back titration method).

Three lots (DS: 0.62, DS: 0.67 and DS: 0.69, respectively) of AcNBKP were obtained and used for the production of the following fiber-reinforced resin compositions and moldings.

C. As the inorganic filler (1) glass fiber (GF), Nittobo GF (CSX3J, fiber length 3 mm, fiber diameter 11 μm) was used.

(2) As the glass wool (GW), GW manufactured by Asahi Fiber Glass Co., Ltd. (white wool, fiber diameter 7-8 μm, fiber length (L) 30-50 mm) was used.

D. Polyamide (powder type, grade A1020LP) manufactured by Unitika Ltd. was used as resin (1) powdery polyamide 6 (sometimes referred to as "PA6 powder").

(2) As the pelletized polyamide 6 (also referred to as "PA6 pellets"), pelletized polyamide 6 (grade: A1020BRL) manufactured by Unitika Ltd. was used.

(3) As powdery polycarbonate (PC-ABS alloy (sometimes referred to as "PC-ABS alloy powder"), powdery PC-ABS alloy (grade: MB8700) manufactured by Mitsubishi Engineering-Plastics Corporation was used.

(4) As pellet-like polycarbonate (PC)-ABS alloy (sometimes referred to as "PC-ABS alloy pellets"), pellet-like PC-ABS alloy (grade: MB8700) manufactured by Mitsubishi Engineering Plastics was used.

E. Inorganic filler-containing masterbatch (MB)
(1) Glass fiber (GF)-containing PA6 pellets (sometimes referred to as "GF-reinforced PA6 pellets") are mastered with Unitika's glass fiber-reinforced PA (grade: A1030GFL, reinforced by 30% glass fiber). Used as a batch.

(2) A glass wool (GW)-containing pellet-like PA6 masterbatch (sometimes referred to as "GW30% PA6 pellet MB" (V)) was produced by the following method. After mixing the above PA6 powder and the above glass wool (GW) at a ratio of PA6/GW = 70/30, it is supplied to a twin-screw extruder and melt-kneaded to obtain a pelletized PA6 composition containing 30% by mass of GW. got stuff This is called "GW30%PA6 pellet MB".

(3) For carbon fiber (CF)-containing PA6 pellets, carbon fiber-reinforced PA6 (PATR-120XCF30) manufactured by Terabo Co., Ltd. was used as a masterbatch (sometimes referred to as "CF30% PA6 pellets").

Extruder model used: KZW15-60MG-KIK (manufactured by Technobell Co., Ltd.)
Operating conditions: Biaxial cylinder set temperature 200-215℃
Screw speed: 200rpm

(4) As the glass fiber (GF) 30 wt% reinforced polycarbonate (also referred to as "GF 30% PC pellets"), pellet-shaped GF-30 wt% reinforced PC (grade GSH2030M) manufactured by Mitsubishi Engineering-Plastics was used.

F. Masterbatch containing AcNBKP (MB)
Hereinafter, "masterbatch" is described as "MB".

(1) Powdered PA6-MB containing AcNBKP
Using the above PA6 powder and AcNBKP, the following powdery PA6-MB (i) and (ii) were produced.

PA6 powder MB containing 15% AcNBKP (i)
This is a PA6 composition containing AcNBKP corresponding to 15% by mass in terms of NBKP.

In order to obtain a powdery composition composed of AcNBKP and PA6 with an NBKP-equivalent content of 15% by mass, a slurry of AcNBKP and powdery PA6 were mixed as a slurry. Since AcNBKP with DS=0.69 is used, the mixing ratio is PA6:AcNBKP=82.31:17.69 in dry weight ratio.

A powdery mixture of PA6 and AcNBKP was prepared by filtering the slurry mixture followed by drying.

Regarding the chemically modified cellulosic fiber and the resin composition (or mixture) containing it, the method of indicating by combining the type of chemically modified fiber and its content (parts by mass) is herein defined as the type of chemically modified fiber. It is displayed by combining the display (abbreviation) shown and the content ratio (parts by mass) of the unmodified fiber.

Therefore, when the above mixture of PA6 and chemically modified NBKP (AcNBKP) is expressed using the type of chemically modified NBKP (AcNBKP) and its content as unmodified fiber, the composition ratio of this mixture is expressed as , PA6/AcNBKP = 85/15 (parts by mass).

PA6 powder MB containing 30% AcNBKP (ii)
This is a PA6 composition containing AcNBKP corresponding to 30% by mass in terms of NBKP.

In order to obtain a powdery composition composed of AcNBKP and PA6 having a content of 30% by mass in terms of NBKP, a powdery composition composed of AcNBKP and PA6 was added from PA6 powder and AcNBKP slurry in the same manner as in (i) above. A slurry mixture was prepared. Since AcNBKP with DS=0.69 is used, the mixing ratio of PA6 and AcNBKP is PA6:AcNBKP=64.62:35.38 in dry weight ratio.

The display of the composition ratio is PA6/AcNBKP = 70/30 (parts by mass).

(2) AcNBKP-containing pelleted PA6-MB
The powdered PA6-MB (ii) containing 30% AcNBKP (PA6/AcNBKP = 70/30) and the powdered PA6 are mixed in the ratios shown in the table below, then fed to the feed port of the twin-screw extruder and melt-kneaded. Then, the following pellet MB (iii) and pellet MB (iv) were prepared.

AcNBKP10%PA6 pellet MB (iii)
A composition consisting of pellet-like AcNBKP and PA6 containing 10% by mass of NBKP was prepared.

AcNBKP15%PA6 pellet MB (iv)
A composition consisting of pellets of AcNBKP and PA6 containing 15% by mass of NBKP was prepared.

AcNBKP in these pelletized PA6-MB microfibrillates during melt-kneading with PA6.

The model of the twin-screw extruder used for the preparation of PA6-MB and the operating conditions are as follows.

Extruder model: KZW15-60MG-KIK (manufactured by Technobell Co., Ltd.)
Extruder operating conditions: Twin-screw cylinder set temperature 200-215°C
Screw speed: 200rpm

(3) PC-ABS alloy powdery MB containing 30% AcNBKP (vi)
A powdery PC-ABS alloy composition containing AcNBKP corresponding to 30% by mass in terms of NBKP was prepared.

In order to obtain a powdery composition composed of AcNBKP and an ABS alloy having an NBKP-equivalent content of 30% by mass, the AcNBKP slurry and the powdery polycarbonate-ABS alloy (PC-ABS alloy) were mixed. . Since AcNBKP with DS=0.67 is used, the mixing ratio is PC-ABS alloy:AcNBKP=64.77:35.23 in dry weight ratio.

A powdery mixture consisting of PC-ABS alloy and AcNBKP was obtained by filtering the slurry mixture followed by drying.

The display of the composition ratio is PC-ABS alloy/AcNBKP = 70/30 (mass parts).

(4) Pellets PC-ABS alloy MB containing AcNBKP
A pellet-like PC-ABS alloy MB containing AcNBKP is referred to as an AcNBKP-containing pellet-like PC-ABS alloy MB.

The PC-ABS alloy powdery MB(vi) containing 30% NBKP (PC-ABS alloy/AcNBKP = 70/30) and the PC-ABS alloy pellets were mixed at the ratios shown in the table below.

A mixture of PC-ABS alloy powdery MB (vi) containing NBKP 30% and the above PC-ABS alloy pellets is supplied to the feed port of a twin-screw extruder and melt-kneaded by the twin-screw extruder to obtain the following AcNBKP 10% PC- ABS alloy pellets MB (vii) and AcNBKP 15% PC-ABS alloy pellets MB (viii) were prepared. See below for the type of extruder and its operating conditions.

AcNBKP10% PC-ABS alloy pellet MB(vii)
This is a composition consisting of pelletized AcNBKP and PC-ABS alloy containing 10% by mass as NBKP.

AcNBKP15% PC-ABS alloy pellet MB (viii)
This is a composition consisting of pelletized AcNBKP and PC-ABS alloy containing 15% by mass as NBKP.

The AcNBKP in the pellet-like PC-ABS alloy MB containing these AcNBKPs undergoes microfibrillation during the melt-kneading of the PC-ABS alloy and the powdery PC-ABS alloy MB containing 30% NBKP. The type of extruder and its operating conditions are as follows.
Extruder model: KZW15-60MG-KIK (manufactured by Technobell Co., Ltd.)
Extruder operating conditions: Twin-screw cylinder set temperature 210-220°C
Screw speed: 200rpm

III. Production and evaluation results of fiber reinforced resin composition
(1) Production of PA6 composition containing AcNBK and GF, and its molding
(1-1) Method of supplying PA6, AcNBK and GF collectively and kneading them to produce a composition
Manufacture of the composition
AcNBKP 15% powder MB(i) (PA6/AcNBKP = 85/15), AcNBKP 30% powder MB(ii) (PA6/AcNBKP = 70/30), (1) PA6 powder, (2) NBKP, and (4) GF were mixed at room temperature at the mixing ratio shown in Table 4.

The resulting mixtures were supplied to a twin-screw extruder, respectively, and these components were melt-kneaded at once to give test numbers PA6-433, PA6-15, PA6-430, PA6-428, PA6- Composite pellets were made that were 429, PA6-431, and PA6-432.

Melt-kneading conditions Cylinder setting temperature: 200-215°C
Screw speed: 200rpm
The AcNBKP component in the manufactured composition is microfibrillated during kneading.

Production of molded body The composite pellet obtained is injection molded (injection molding machine NPX7 (manufactured by Nissei Plastic Industry Co., Ltd.)), and a strip-shaped test piece of width x length x thickness = 10 x 80 x 4 mm ( A compact) was obtained.

The cylinder set temperature of the injection machine was 210-230°C.

Test Results of Molded Body The flexural modulus and flexural strength of the above molded body (test piece) were measured.

Table 5 shows the measurement results. 1 and 2 show the relationship between the density of the molded body and the bending elastic modulus, and the relationship between the density of the molded body and the bending strength, respectively.

The density of the molded body can be calculated from the density and mass ratio of each composition that constitutes it.

Results of dynamic viscoelasticity test In order to evaluate the moldability of the composition of the present invention, a dynamic viscoelasticity test was conducted, and Table 5 shows the complex viscosity at 628 rad/sec.

FIG. 1 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.69) and glass fiber (GF).

FIG. 2 is a diagram showing the relationship between the density and bending strength of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.69) and glass fiber (GF).

In FIGS. 1 and 2, the PA6 molded body was produced by supplying PA6, AcNBKP and GF together to a kneader, melt kneading them, and injection molding them.

In both figures, the flexural modulus or flexural strength of PA6/AcNBKP/GF composites plotted against density (red mark) connects unreinforced PA6 and PA6/GF = 80/20. It showed a higher value at the same density than the value on the straight line. From this, it can be seen that in the PA6/AcNBKP/GF composite, the reinforcing effect of AcNBKP and GF is higher than that of GF alone at the same density.

Furthermore, based on the flexural modulus per density (MPa / composition density) of the PA6 composition containing 20 Wt% glass fiber (GF) (test number PA6-433), the flexural modulus per density and per density of each sample were compared.

As shown in Table 5, Test No. PA6-428 (PA6/AcNBKP/GF = 90/5/5), PA6-429 (PA6/AcNBKP/GF = 85/5/10), PA6-431 (PA6/ AcNBKP/GF = 85/10/5) and PA6-432 (PA6/AcNBKP/GF = 80/10/10) elastic modulus ratio per density is the standard value (elastic modulus per density of PA6 composition containing GF20Wt%) It was 1.05 to 1.42 times compared to .

The bending strength per density (ratio of strength per density) of the compositions of test numbers PA6-429 to PA6-432 was 1.07 to 1.16 times the reference value.

Thus, compared to GF-reinforced PA6, the PA6/AcNBKP and PA6/AcNBKP/GF materials are lighter weight, higher strength and higher modulus materials.

The elastic modulus ratio per density of PA6-430 (PA6/AcNBKP=90/10) is 1.10 compared to that of the standard (PA6/GF=80/20).

On the other hand, the elastic modulus ratios per density of PA6-429, PA6-431 and PA6-432 are 1.20, 1.24 and 1.42 times that of the standard (PA6/GF=80/20), respectively. From this, it can be said that even in comparison with PA6-430 containing only AcNBKP, the hybridization of AcNBKP and GF made it possible to achieve a lighter weight and a higher elastic modulus.

The strength per density ratio of PA6-430 is 1.09 compared to that of the standard (PA6/GF=80/20).

In comparison, PA6-431 and PA6-432 have high strength to density ratios (1.12 and 1.16, respectively). From this, it can be said that even compared to PA6-430, which contains only AcNBKP, the hybridization of AcNBKP and CNF has achieved light weight and high strength.

Comparing the moldability of the compositions of the present invention from the viewpoint of dynamic viscoelasticity, the compositions of the present invention (PA6-429 and PA6-431) have lower complex viscosities than the control (PA6-430), It can be said that the moldability is good.

(1-2) Method of melting and mixing AcNBKP/PA6 pellets and GF/PA6 pellets with an injection machine and injection molding
AcNBKP10wt% pellet MB(iii) (PA6/AcNBKP = 90/10), AcNBKP15wt% pellet MB(iv) (PA6/AcNBKP = 85/15), (4) PA6-GF30wt% pellet, and (5) PA6 pellet , were mixed at the mixing ratios shown in Table 6, respectively.

The obtained mixtures are supplied to an injection molding machine, melted and injection molded to obtain strip-shaped test pieces (width x length x thickness = 10 x 80 x 4 mm) (PA6-437, 438, 439 , 440, 441 and 442). The model number of the injection machine is NPX7 (manufactured by Nissei Plastic Industry Co., Ltd.).

The cylinder set temperature of the injection machine was 210-230°C.

Test Results of Molded Body The flexural modulus and flexural strength of the above molded body (test piece) were measured.

Table 7 shows the measurement results. 3 and 4 show the relationship between the density of the molded body and the bending elastic modulus, and the relationship between the density of the molded body and the bending strength, respectively.

In addition, in order to evaluate the moldability of the composition of the present invention, a dynamic viscoelasticity test was conducted, and Table 7 shows the complex viscosity at 628 rad/sec.

FIG. 3 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF).

FIG. 4 is a diagram showing the relationship between the density and bending strength of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF).

The PA6 molded body containing acetylated NBKP and glass fiber (GF) shown in FIGS. manufactured by

Regarding the flexural modulus in Fig. 3, the flexural modulus of the PA6/AcNBKP/GF composite with the same density was higher than the value on the straight line connecting the unreinforced PA6 and PA6/GF = 80/20. . From this, it can be seen that the PA6/AcNBKP/GF composite material has a higher reinforcing effect due to AcNBKP and GF than the reinforcing effect due to GF at the same density.

In the relationship diagram of density and flexural strength in Fig. 4, the flexural strength of PA6/AcNBKP/GF composite material with the same density compared to the value on the straight line connecting unreinforced PA6 and PA6/GF = 80/20 is large, it can be seen that the reinforcing effect of AcNBKP and GF is higher than that of GF.

Furthermore, the elastic modulus ratio per density of each sample was compared based on the bending elastic modulus per density (elastic modulus ratio per density) of the PA6 composition containing 20 Wt% glass fiber (GF) (test number PA6-442).

As shown in Table 7, Test Nos. PA6-438 (PA6/AcNBKP/GF = 85/5/10), PA6-440 (PA6/AcNBKP/GF = 85/10/5) and PA6-441 (PA6/ AcNBKP/GF = 80/10/10) was 1.03 to 1.21 times higher than the standard value.

Compared to GF reinforced PA6, the PA6/AcNBKP/GF material is a lightweight and high modulus material.

The elastic modulus per density ratio of PPA6-439 containing only AcNBKP (PA6/AcNBKP=90/10) is 0.96 relative to the standard.

On the other hand, study numbers PA6-438 (PA6/AcNBKP/GF = 85/5/10), PA6-440 (PA6/AcNBKP/GF = 85/10/5) and PA6-441 (PA6/AcNBKP/GF = 80/ 10/10) has a flexural modulus ratio per density of 1.03-1.21, which is larger than that (0.96) of PA6-439 containing only AcNBKP (PA6/AcNBKP=90/10). As described above, even when compared with a compact containing only AcNBKP, the hybridization of AcNBKP and GF made it possible to achieve light weight and high elastic modulus.

With respect to moldability, the compositions of the present invention (PA6-438, PA6-440, and PA6-441) have lower complex viscosities than the control (PA6-439), so it is believed that they have good moldability. I can say.

(2) Production of PA6 composition containing AcNBK and GW and its molding
AcNBKP 10 wt% pellets MB (iii), AcNBKP 15 wt% pellets MB (iv), GW 30 wt% pellets MB (v), and (5) PA6 pellets were mixed at the composition ratios shown in Table 8, respectively.

The resulting mixtures were each supplied to an injection machine and melted to produce a PA6 composition containing AcNBKP and GW. By injection molding this (NPX7 (manufactured by Nissei Plastic Industry Co., Ltd.)), a strip-shaped molded body of width x length x thickness = 10 x 80 x 4 mm (specimen test number, PA6-448, 449, 450, 451, 452 and 453) were produced.

The model number of the injection machine used is NPX7 (manufactured by Nissei Plastic Industry Co., Ltd.). The cylinder set temperature of the injection machine was 210-230°C.

Test Results of Molded Body The flexural modulus and flexural strength of the above molded body (test piece) were measured.

Table 9 shows the measurement results. 5 and 6 show the relationship between the density of the compact and the bending elastic modulus, and the relationship between the density and the bending strength of the compact, respectively.

In addition, in order to evaluate the moldability of the composition of the present invention, a dynamic viscoelasticity test was conducted, and Table 9 shows the complex viscosity at 628 rad/sec.

FIG. 5 is a diagram showing the relationship between the density and flexural modulus of a PA6 molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass wool (GW).

FIG. 6 is a diagram showing the relationship between the density and bending strength of PA6 molded bodies containing acetylated NBKP (AcNBKP, DS=0.67) and glass wool (GW).

In FIGS. 5 and 6, the PA6 molded body containing AcNBKP and GW was manufactured by supplying a mixture of AcNBKP-containing PA6 pellets and GW-containing PA6 pellets to an injection molding machine, melt-mixing the mixture, and injection-molding it.

In both figures, the physical properties of the PA6/AcNBKP/GW composite with the same density were higher than those on the straight line connecting the unreinforced PA6 and PA6/GW = 80/20. It can be seen that the reinforcing effect of AcNBKP and GW is higher than that of GW at the same density of wood.

Based on the flexural modulus per density (flexural modulus per density (MPa/composition density)) and the flexural strength per density (bending strength per density) of the PA6 molded body containing GW20Wt% (test number PA6-453), The flexural modulus per density and the flexural strength per density of the PA6 composition containing AcNBK and GW were compared.

As shown in Table 9, test numbers PA6-448 (PA6/AcNBKP/GW = 90/5/5), PA6-449 (PA6/AcNBKP/ GW = 85/5/10), PA6-451 (PA6/AcNBKP/GW = 85/10/5), and PA6-452 (PA6/AcNBKP/GW = 80/10/10) , 1.31 to 1.78 times the above standard value, and the strength per density ratio was 1.35 to 1.48 times the above standard value.

Thus, compared to GW-reinforced PA6, the PA6/AcNBKP and PA6/AcNBKP/GW materials are lightweight, high strength and high modulus materials.

The flexural modulus ratio per density of PA6-450 is 1.55.

On the other hand, those of PA6-451 and PA6-452 are 1.69 and 1.78 respectively. In this way, even compared to PA6-450, which is only AcNBKP, we were able to achieve light weight and high elastic modulus by hybridizing AcNBKP and GW.

Regarding the moldability of the fiber-reinforced composition of the present invention, the composition of the present invention (PA6-451) has a lower complex viscosity than the control (PA6-450), and can be said to have good moldability.

(3) Manufacture of compositions containing AcNBK, GF and PC-ABS alloys and their moldings
CNF 10 wt% pellets MB (vii), CNF 15 wt% pellets MB (viii), GF 30 wt% reinforced PC pellets, and (11) PC-ABS alloy pellets were mixed at the composition ratio shown in Table 10, respectively.

The resulting mixture is supplied to an injection machine, melted, and injection molded to obtain strip-shaped molded articles of the present invention and control molded articles (test pieces ) was prepared.

The test numbers of the specimens were PC-19, 20, 21, 22, 23 and 24, respectively.

The cylinder temperature of the injection machine was set at 210-250°C.

The composition containing AcNBK, GF and PC-ABS alloy, and the AcNBKP in the compact are nanofibrillated.

Test Results of Molded Body The flexural modulus and flexural strength of the above molded body (test piece) were measured.

Table 11 shows the measurement results. 7 and 8 show the relationship between density and flexural modulus of the molded body, and the relationship between density and flexural strength of the molded body, respectively.

FIG. 7 is a diagram showing the relationship between the density and flexural modulus of a PC-ABS alloy molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF).

FIG. 8 is a diagram showing the relationship between the density and bending strength of a PC-ABS alloy molded body containing acetylated NBKP (AcNBKP, DS=0.67) and glass fiber (GF).

In FIGS. 7 and 8, the PC-ABS alloy molded body was produced by supplying a mixture of AcNBKP-containing PC-ABS alloy pellets and GF-containing PC pellets to an injection molding machine, melt-mixing the mixture, and injection-molding the mixture.

In both figures, the flexural modulus of PC-ABS alloy/AcNBKP/GF composites, or The values obtained by plotting the bending strength against the density (marked with red ♦) showed high values at the same density. From this, it can be seen that the PC-ABS alloy/AcNBKP/GF composite material has a higher reinforcing effect due to AcNBKP and GF than the reinforcing effect due to GF at the same density.

Furthermore, based on the data in Table 11, the flexural modulus per density (flexural modulus per density) of the PC-ABS alloy composition containing 20 Wt% glass fiber (GF) (Test No. PC-24) was compared as a standard. did.

Compared to its reference value (modulus ratio per density of 1.00), test numbers PC-20 (alloy/AcNBKP/GF = 85/5/10), PC-22 (alloy/AcNBKP/GF = 85/10/ 5) and PC-23 (alloy/AcNBKP/GF = 80/10/10) have a modulus per density ratio of 1.04 to 1.21. From this, it can be seen that the alloy/AcNBKP/GF composite material is lighter and has a higher elastic modulus than the GF-reinforced PC-ABS alloy.

In terms of bending strength per density (ratio of strength per density) of compacts, test number PC-20 (alloy/AcNBKP/GF = 85/5/10) is equivalent to PC-24 (alloy/GF=80/20). is.

The elastic modulus ratio per density of PC-6 (alloy/AcNBKP=90/10) is 0.98.

In contrast, the modulus per density ratios of PC-20, PC-22 and PC-23 were 1.04, 1.11 and 1.21, respectively. Therefore, compared to composite PC-6 (alloy/AcNBKP=90/10) composed only of AcNBKP, hybridization of AcNBKP and GF made it possible to achieve light weight and high elastic modulus.

The strength per density ratio of PC-6 is 0.84.

In contrast, the intensity per density ratios of PC-19, PC-20, PC22 and PC-23 were 0.91, 1.01, 0.87 and 0.93, respectively. Therefore, compared to PC-6 (alloy/AcNBKP=90/10) containing only AcNBKP, hybridization of AcNBKP and GF made it possible to achieve lighter weight and higher strength.

(4) A method of melt-mixing AcNBKP/PA6 pellets and CF/P6 pellets in an injection molding machine and injection molding them.
Using CF30% PA6 pellets instead of PA6-GF30% pellets, described in the above "(1-2) Method of melting and mixing AcNBKP / PA6 pellets and GF / PA6 pellets with an injection machine and injection molding)" According to the method, AcNBKP10wt% pellets (PA6/AcNBKP = 90/10), AcNBKP15wt% pellets (PA6/AcNBKP = 85/15), CF30%PA6 pellets and PA6 pellets were mixed according to the mixing ratio in Table 6. , respectively, were supplied to an injection molding machine, melted, and injection molded to obtain strip-shaped test pieces (PA6-571 to 576 and 585) of width x length x thickness = 10 x 80 x 4 mm.

The model number of the injection machine is NPX7 (manufactured by Nissei Plastic Industry Co., Ltd.). The cylinder set temperature of the injection machine was 210-230°C.

Test Results of Molded Body The flexural modulus and flexural strength of the above molded body (test piece) were measured.

Table 12 shows the measurement results. 9 and 10 show the relationship between the density of the compact and the bending elastic modulus, and the relationship between the density and the bending strength of the compact, respectively.

In addition, a dynamic viscoelasticity test was conducted to evaluate the moldability of the composition of the present invention, and Table 12 shows the complex viscosity at 628 rad/sec.

As can be seen from Table 12, the flexural modulus and flexural strength are greatly increased when carbon fiber is combined with PA6. For example, a PA6 composition containing 10% CF (PA6-585 = PA6 / CF = 90/10) has a flexural modulus of 7460 MPa and a flexural strength of 162 MPa, and a PA6 composition containing 10% AcNBKP (PA6-573=PA6/AcNBKP=90/10) (flexural modulus 4910 MPa and bending strength 129 MPa).

Comparing the flexural modulus per density and the flexural strength per density, the former flexural modulus per density is 1.5 times that of the latter, and the former flexural strength per density is 1.5 times that of the latter. 1.25 times.

From this data, at first glance, the effect of combining carbon fiber and chemically modified microfibrillated cellulose fiber (AcNBKP) in a fiber-reinforced composition is unclear.

However, the value on the regression line obtained from the relationship between the density and flexural modulus of PA6, PA6-585 (PA6/CF-90/10) and PA6-576 (PA6/CF-90/20) is , is very close to the flexural modulus per density of the PA6 composition containing AcNBKP and CF (see FIG. 9). It can be said that the performance is comparable to that of the CF-containing composition.

In addition, it can be said that the bending strength per density of the PA6 composition containing AcNBKP and CF is comparable to that of the CF-containing composition (see FIG. 10). This means that it is possible to save energy and reduce costs by using chemically modified microfibrillated cellulose fibers and carbon fibers in combination instead of using carbon fibers that require high energy and cost for production. It can be said.

(5) Measurement results of fiber length and fiber diameter of AcNBKP before compounding (melt-kneading) with resin and AcNBKP in resin compound
Microscopic observation of the fibers was performed at low magnification from 100 to 1000 and high magnification of 5000.

In the observation at low magnification, many coarse fibers were found by observing at several magnifications and fields of view, and their fiber diameters and fiber lengths were measured.

In the high-magnification observation, we observed fibers that were undergoing defibration, and measured their fiber diameters and fiber lengths. By such an observation method, it was possible to comprehensively observe the fiber diameter and fiber length from the defibrated fiber to the unfibrillated fiber contained in the sample.

FIG. 11 shows an electron microscopic image of AcNBKP (AcNBKP before melt-kneading with PA6) used for the compact of test number PA6-430. In addition, FIG. 12 shows an electron microscope image of the fibers in the sample prepared from the molded body of test number PA6-430, and FIG. 13, and FIG. 14 shows an electron microscopic image of the fibers in the sample prepared from the compact of Test No. PA6-451.

When observed in this way, the diameter of AcNBKP before melt-kneading with the resin was about several tens of nm to 5 μm for thin ones and 20 to 50 μm for thick ones (Fig. 11 AcNBKP before resin kneading under a microscope Observation image).

When PA6 was eluted from the molded bodies (PA6-430, PA6-431 and PA6-451, respectively), and the fibers remaining after removal were observed at low magnification and at high magnification as described above, the diameter A thin one was about several tens of nm to 1 μm, and a thick one was 10 to 30 μm (see FIGS. 12 to 14).

From the above, it can be seen that the chemically modified cellulosic fiber undergoes fibrillation during melt-kneading with the resin and fibrillates.

INDUSTRIAL APPLICABILITY As described above, the present invention was able to provide a fiber-reinforced resin composition that is lightweight and has excellent strength characteristics, and a molded article thereof.

Claims (9)

A fiber-reinforced resin composition,
The fiber-reinforced resin composition contains (A) chemically modified microfibrillated cellulose fibers, (B) an inorganic filler and (C) a thermoplastic resin,
A fiber-reinforced resin composition in which the (A) chemically modified microfibrillated cellulose fiber and the (B) inorganic filler satisfy the following requirements (a) and (b):
(a) (A) chemically modified microfibrillated cellulosic fibers are
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is one or two selected from the group consisting of an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, and -(CH ₂ ) _n-1 COO ^{-X +} The above are shown, and n is an integer of 2 to 4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
It is a microfibrillated fiber composed of a chemically modified cellulosic polymer represented by.
(b) (B) The inorganic filler is one or more fillers selected from the group consisting of glass fiber, glass wool, carbon fiber, fine glass powder, carbon black, carbon nanotube, graphene, kaolin and nanoclay. The fiber according to claim 1, wherein R in formula (1) of the (a) requirement is an acetyl group, a propionyl group, a carboxymethyl group, a salt of a carboxymethyl group, a carboxyethyl group, or a salt of a carboxyethyl group. Reinforced resin composition. 3. The fiber-reinforced resin composition according to claim 1, wherein R in formula (1) of the requirement (a) is an acetyl group. The fiber-reinforced resin composition according to any one of claims 1 to 3, wherein the inorganic filler (B) of the requirement (b) is glass fiber or carbon fiber. The fiber-reinforced resin according to any one of claims 1 to 4, wherein (Lg)Cell- in the formula (1) of the (a) requirement is a residue obtained by removing hydroxyl groups from polysaccharides and lignin constituting lignocellulose. Composition. The (C) thermoplastic resin is polyamide, polyolefin, aliphatic polyester, aromatic polyester, polyacetal, polycarbonate, polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), polycarbonate-ABS alloy (PC-ABS alloy). and modified polyphenylene ether (m-PPE). A molded article made of the fiber-reinforced resin composition according to any one of claims 1 to 6. A method for producing a fiber-reinforced resin composition according to any one of claims 1 to 6,
(i) Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is one or two selected from the group consisting of an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, and -(CH ₂ ) _n-1 COO ^{-X +} The above are shown, and n is an integer of 2 to 4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
A chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by
(ii) (B) inorganic filler, and (iii) (C) thermoplastic resin are melt-kneaded to obtain (A) chemically modified microfibrillated cellulosic fiber, (B) inorganic filler, and (C) thermoplastic resin. A method for producing a fiber reinforced resin composition containing
A method for producing a fiber-reinforced resin composition, wherein the (A) chemically modified microfibrillated cellulose fibers and the (B) inorganic filler satisfy the requirements of (a) and (b). A method for producing a fiber-reinforced resin composition according to any one of claims 1 to 6,
Process (1):
Formula (1):
(Lg) Cell-OR (1)
[In the formula, (Lg)Cell- represents a residue obtained by removing hydroxyl groups from polysaccharides and lignin that constitute cellulose, holocellulose and/or lignocellulose in the cellulosic polymer.
In the formula, -OR indicates that hydrogen atoms of some hydroxyl groups in polysaccharides and lignin constituting cellulose, holocellulose and/or lignocellulose in the cellulosic polymer are substituted with the substituent R.
In the formula, R is one or two selected from the group consisting of an acyl group having 2 to 4 carbon atoms, -(CH ₂ ) _n-1 COOH, and -(CH ₂ ) _n-1 COO ^{-X +} The above are shown, and n is an integer of 2 to 4. The COO ⁻ X ⁺ represents a group in which a carboxy group is in an inorganic or organic salt state. ]
Chemically modified cellulose pulp made of a chemically modified cellulose polymer represented by and (C) a step of kneading a thermoplastic resin, and Step (2):
(A) a chemically modified microfibrillated cellulose fiber by a method comprising a step of melt-kneading the kneaded product obtained in the step (1) and (B) a resin composition containing an inorganic filler and a thermoplastic resin; , (B) an inorganic filler, and (C) a thermoplastic resin. A method for producing a fiber-reinforced resin composition that satisfies the requirements of a) and (b).

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