JP2021037769A - Fibrous cellulose-containing material and method for producing the same, fibrous cellulose dry body and method for producing the same, and fibrous cellulose composite resin and method for producing the same - Google Patents

Abstract

To provide a fibrous cellulose-containing material that has excellent dispersibility of cellulose fiber, facilitates dehydration, and does not necessarily require blending of organic solvent and a method for producing the same, and a fibrous cellulose dry body using the fibrous cellulose-containing material and the production method, and a fibrous cellulose composite resin and a method for producing the same.SOLUTION: Raw material pulp is fibrillated in a range in which an average fiber width is kept at 0.1 μm or more to obtain a dispersion of micro fiber cellulose, the dispersion and a resin powder with an average particle size of 1-1500 μm are mixed to obtain a fibrous cellulose-containing material, the fibrous cellulose-containing material is dried to obtain a fibrous cellulose dry body, and the dry body is kneaded to obtain a fibrous cellulose composite resin.SELECTED DRAWING: None

Description

The present invention relates to a fibrous cellulose-containing material and a method for producing the same, a dried fibrous cellulose and a method for producing the same, and a fibrous cellulose composite resin and a method for producing the same.

In recent years, nanotechnology has been attracting attention for the purpose of refining substances to the nanometer level and obtaining new physical properties different from the conventional properties of substances. Cellulose nanofibers produced from pulp, which is a cellulosic raw material, by chemical treatment, crushing treatment, etc. are excellent in strength, elasticity, thermal stability, etc. It is expected to be used in industrial applications such as fillers for chromatography analysis equipment, fillers for blending resins and rubbers, and blending agents for cosmetics such as lipsticks, powder cosmetics, and emulsified cosmetics. There is. In addition, since cellulose nanofibers have excellent water-based dispersibility, they are viscosity-retaining agents for foods, cosmetics, paints, etc., fortifiers for food raw material fabrics, water-retaining agents, food stabilizers, low-calorie additives, and emulsification. It is also expected to be used in many applications such as stabilizing aids.

At present, it has been proposed to use cellulose nanofibers obtained by refining plant fibers as a reinforcing material for resin. However, when cellulose nanofibers are used as the resin reinforcing material, the cellulose nanofibers irreversibly aggregate due to intermolecular hydrogen bonds derived from the hydroxyl groups of the polysaccharide. In addition, the fibers are torn during kneading with the resin, and a sufficient three-dimensional network cannot be constructed in the resin. Therefore, even if the cellulose nanofibers are used as a reinforcing material, the dispersibility of the cellulose nanofibers in the resin is poor, and a sufficient three-dimensional network cannot be constructed. As a result, there is a problem that the reinforcing effect of the resin is not sufficiently exhibited.

Therefore, Patent Document 1 proposes the use of an organic solvent, particularly a water-soluble solvent, in order to enhance the dispersibility of the cellulose fibers. However, as the document itself points out, the use of an organic solvent causes problems such as a decrease in productivity and an increase in manufacturing cost. Further, when an organic solvent is used, the strength of the composite resin to which the cellulose fiber is added may be insufficient.

Therefore, the proposal of Patent Document 2 is helpful. The document proposes adding and mixing a resin powder having an average particle size of 1000 μm or less to a dispersion of microfibrillated cellulose in order to eliminate the need for an organic solvent. According to the document, this "allows the preparation of a homogeneous mixed dispersion, and by dehydrating and drying it, the dispersibility of microfibrillated cellulose in the resin is improved, and a higher temperature or organic solvent is required." It is said that it will not be done (paragraph 0004 of the same document). However, this document does not give consideration to dehydration and drying after dispersion. The document states that "the average fiber diameter of microfibrillated cellulose is preferably 4 nm to 400 nm" for the microfibrillated cellulose to which the resin powder is added (paragraph 0009 of the same document). It is premised on the use of nanofibers. However, cellulose nanofibers have high water retention and are difficult to dehydrate. Therefore, it is necessary to make a proposal that considers dehydration as well as dispersibility. Further, when the cellulose nanofibers are dehydrated and dried, there is a problem that the cellulose fibers aggregate due to hydrogen bonds and it becomes difficult to disperse them. However, the same document does not disclose a solution to this point as well.

However, the problem of dispersibility itself is pointed out by, for example, Patent Document 3. The document proposes a resin modification additive containing cellulose nanofibers having an average fiber diameter of 1 to 200 nm and resin particles having an average particle size of 0.01 to 500 μm in order to solve the problem of dispersibility. .. However, this document does not consider dehydration. On the contrary, since the cellulose nanofibers of the same document have a carboxyl group introduced therein, the hydrophilicity becomes higher, the dehydration property is lowered, and the dispersibility in the resin becomes insufficient.

Japanese Patent No. 5863269 Japanese Patent No. 5030667 Japanese Patent No. 5923370

The main problem to be solved by the present invention is a fibrous cellulose-containing material which is excellent in dispersibility of cellulose fibers, easy to dehydrate, and does not require the inclusion of an organic solvent, a method for producing the same, and the content and the method for producing the same. It is an object of the present invention to provide a dried fibrous cellulose body and a fibrous cellulose composite resin utilizing the above, and a method for producing these.

In order to solve the above problems, the present inventors have applied various treatments to cellulose nanofibers (cellulose fine fibers), and have searched for a kneading method of cellulose nanofibers and a resin. In other words, various studies were conducted on the premise of using cellulose nanofibers. However, when the cellulose nanofibers are composited with the resin, for example, even if hydrophobic modification is performed or a compatibilizer is used, the dispersibility of the cellulose nanofibers in the resin is not sufficient, and the dispersibility in the resin is not sufficient. Since a sufficient three-dimensional network was not formed, a sufficient reinforcing effect could not be obtained. However, in the process of the research, it is possible that the raw material fiber is microfiber cellulose, which has better dispersibility in the resin than the cellulose nanofiber, and a sufficient three-dimensional network is formed in the resin. It was found that it is possible and a good reinforcing effect can be obtained. Moreover, it has been found that the microfiber cellulose having a predetermined fiber width is improved in dehydration property when combined with a resin powder having a predetermined particle size. This is based on the premise of the discovery that microfiber cellulose was used instead of the use of cellulose nanofibers, which was originally considered to be incapable of dehydration. That is, it was found that the use of microfiber cellulose is one factor, and that the dehydration property is improved by mixing the resin powder. The fibrous cellulose-containing material thus obtained does not require the use of an organic solvent.

Based on the above circumstances, the means shown below have come up with the idea to solve the above problems.

(Means according to claim 1)
Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. Including
The blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose is 50 to 100,000.
A fibrous cellulose-containing material.

(Means according to claim 2)
The ratio of the fiber length of the microfiber cellulose to 0.2 mm or less is 12% or more.
The fibrous cellulose-containing product according to claim 1.

(Means according to claim 3)
The pulp viscosity of the microfiber cellulose is 2 cps or more.
The fibrous cellulose-containing product according to claim 1 or 2.

(Means according to claim 4)
The microfiber cellulose has been modified with a polybasic acid and / or
The fibrous cellulose-containing material contains a polybasic acid.
The fibrous cellulose-containing product according to any one of claims 1 to 3.

(Means according to claim 5)
Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. The fibrous cellulose-containing material containing 50 to 100,000 of the resin powder in an amount of 100 parts by mass of the microfiber cellulose is dried.
A dried fibrous cellulose body.

(Means according to claim 6)
Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. A dried product containing a fibrous cellulose containing 50 to 100,000 of the resin powder in an amount of 100 parts by mass of the microfiber cellulose is kneaded.
A fibrous cellulose composite resin characterized by this.

(Means according to claim 7)
Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and the resin powder having an average particle size of 125 to 1500 μm are mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose is 50 to 100,000.
A method for producing a fibrous cellulose-containing product.

(Means according to claim 8)
Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and a resin powder having an average particle size of 125 to 1500 μm were mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose was 50 to 100,000 to obtain a fibrous cellulose-containing material.
This fibrous cellulose-containing material is concentrated so that the water content is 95% or less, and then dried.
A method for producing a dried fibrous cellulose product.

(Means according to claim 9)
Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and a resin powder having an average particle size of 125 to 1500 μm were mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose was 50 to 100,000 to obtain a fibrous cellulose-containing material.
This fibrous cellulose-containing material was dried to obtain a fibrous cellulose dried product.
Knead this dried fibrous cellulose
A method for producing a fibrous cellulose composite resin.

(Means according to claim 10)
The dried fibrous cellulose and the resin pellets shall be kneaded.
The mixing ratio of the resin pellets to 100 parts by mass of the resin powder is 10 to 100,000 parts by mass.
The method for producing a fibrous cellulose composite resin according to claim 9.

According to the present invention, a fibrous cellulose-containing material which has excellent dispersibility of cellulose fibers, is easy to dehydrate, and does not require the inclusion of an organic solvent and a method for producing the same, and fibrous cellulose using the content and the manufacturing method. It is a dried product, a fibrous cellulose composite resin, and a method for producing these.

Next, a mode for carrying out the invention will be described. The embodiment of the present invention is an example of the present invention, and the scope of the present invention is not limited to the scope of the present embodiment.

The conventional main flow of production of the fibrous cellulose composite resin is to defibrate the raw material fibers to obtain a cellulose nanofiber dispersion liquid, and dry the cellulose nanofiber dispersion liquid to obtain a fibrous cellulose dried product, and this fibrous cellulose. The dried product and the resin pellets were mixed to obtain a fibrous cellulose composite resin. On the other hand, in this embodiment, the raw material fibers are defibrated to obtain a microfiber cellulose dispersion, and resin powder is added (mixed) to the microfiber cellulose dispersion to obtain a fibrous cellulose-containing material, and the fibrous cellulose is obtained. The contained matter is dehydrated and dried to obtain a fibrous cellulose dried product, and the fibrous cellulose dried product is kneaded to obtain a fibrous cellulose composite resin. In other words, the method of this embodiment limits the degree of defibration of the raw material fibers to microfiber cellulose instead of cellulose nanofibers, and instead of mixing the fibrous cellulose dried product and the resin, the microfiber cellulose dispersion and the resin In addition to the point of mixing with and the point of using a powdery resin instead of a pellet-like resin at that time, and the point of dehydrating the fibrous cellulose-containing material prior to drying, it is significantly different from the conventional method. different. Therefore, in the following, the present embodiment will be described in detail focusing on these differences.

(Raw material fiber)
Microfiber cellulose having an average fiber width of 0.1 μm or more can be obtained by refining (defibrating) the raw material fibers (pulp fibers). As the raw material fiber, one or more kinds can be selected and used from plant-derived fiber, animal-derived fiber, microorganism-derived fiber and the like. However, it is preferable to use pulp fiber which is a plant fiber. When the raw material fiber is pulp fiber, it is inexpensive and the problem of thermal recycling can be avoided.

Plant-derived fibers include wood pulp made from broadleaf trees, coniferous trees, etc., non-wood pulp made from straw bagasse, etc., recovered waste paper, used paper pulp made from waste paper, etc. (DIP). Species or two or more species can be selected and used.

As the wood pulp, select one or more from chemical pulp such as hardwood kraft pulp (LKP) and softwood kraft pulp (NKP), mechanical pulp (TMP), and used paper pulp (DIP). Can be done. These pulps are pulps used for papermaking, and by using these pulps, existing equipment can be effectively utilized.

The hardwood kraft pulp (LKP) may be hardwood bleached kraft pulp, hardwood unbleached kraft pulp, or hardwood semi-bleached kraft pulp. Similarly, the softwood kraft pulp (NKP) may be softwood bleached kraft pulp, softwood unbleached kraft pulp, or softwood semi-bleached kraft pulp.

Further, the used paper pulp (DIP) may be magazine used paper pulp (MDIP), newspaper used paper pulp (NDIP), stepped used paper pulp (WP), or other used paper pulp. Good.

Further, as the mechanical pulp, for example, stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), chemi-grand pulp (CGP), thermo-grand pulp (TGP), ground pulp (GP). ), Thermomechanical pulp (TMP), Chemithermomechanical pulp (CTMP), Refiner mechanical pulp (RMP), Bleached thermomechanical pulp (BTMP), etc. can be selected and used. ..

(Preprocessing)
The raw material fibers are preferably pretreated by a chemical method prior to defibration. By pretreating by a chemical method prior to the miniaturization treatment (defibration), the number of times of the miniaturization treatment can be significantly reduced, and the energy of the miniaturization treatment can be significantly reduced.

Pretreatment by chemical method includes hydrolysis of polysaccharide with acid (acid treatment), hydrolysis of polysaccharide with enzyme (enzyme treatment), swelling of polysaccharide with alkali (alkali treatment), oxidation of polysaccharide with oxidizing agent (oxidation treatment). ), Reduction of polysaccharides with a reducing agent (reduction treatment), and the like can be exemplified.

By applying an alkali treatment prior to the micronization treatment, some of the hydroxyl groups of hemicellulose and cellulose possessed by the pulp are dissociated, and the molecules are anionized to weaken the intramolecular and intermolecular hydrogen bonds, resulting in pulp fibers in the miniaturization treatment. Has the effect of promoting the dispersion of.

As the alkali, for example, organic alkalis such as sodium hydroxide, lithium hydroxide, potassium hydroxide, aqueous ammonia, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide are used. However, from the viewpoint of production cost, it is preferable to use sodium hydroxide.

When the enzyme treatment, the acid treatment, and the oxidation treatment are performed prior to the micronization treatment, the water retention degree of the microfiber cellulose can be lowered, the crystallinity can be increased, and the homogeneity can be increased. In this regard, it is considered that the lower the water retention level of the microfiber cellulose, the better the dispersibility in the resin, and the higher the homogeneity of the microfiber cellulose, the less the defects that cause the composite resin to be destroyed. As a result, the ductility of the resin is improved. It is considered that a composite resin having high strength that can be held can be obtained. In addition, hemicellulose and the amorphous region of cellulose contained in pulp are decomposed by enzyme treatment, acid treatment, and oxidation treatment, and as a result, the energy of miniaturization treatment can be reduced, and the homogeneity and dispersibility of fibers are improved. be able to. Moreover, if the proportion of the cellulose crystal region, which is considered to be rigid and has low water retention, in the entire fiber, the molecular chains are aligned, the dispersibility is improved and the aspect ratio is expected to decrease, but the ductility is maintained. At the same time, a composite resin having high mechanical strength can be obtained.

Among the above-mentioned various treatments, it is preferable to carry out an enzyme treatment, and in addition, it is more preferable to carry out one or more treatments selected from an acid treatment, an alkali treatment and an oxidation treatment. Hereinafter, the alkali treatment will be described in detail.

As a method of alkaline treatment, for example, there is a method of immersing the raw material fiber in an alkaline solution.

The alkaline compound contained in the alkaline solution may be an inorganic alkaline compound or an organic alkaline compound. Examples of the inorganic alkali compound include hydroxides of alkali metals or alkaline earth metals, carbonates of alkali metals or alkaline earth metals, phosphoroxates of alkali metals or alkaline earth metals, and the like. Further, as the hydroxide of the alkali metal, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide and the like can be exemplified. Examples of the hydroxide of the alkaline earth metal include calcium hydroxide and the like. Examples of the alkali metal carbonate include lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate and the like. Examples of the carbonate of the alkaline earth metal include calcium carbonate and the like. Examples of the alkali metal phosphate salt include lithium phosphate, potassium phosphate, trisodium phosphate, disodium hydrogen phosphate and the like. Examples of the alkali earth metal phosphate include calcium phosphate, calcium hydrogen phosphate, and the like.

Examples of the organic alkaline compound include ammonia, aliphatic amines, aromatic amines, aliphatic ammonium, aromatic ammonium, heterocyclic compounds and their hydroxides, carbonates and phosphates. Specifically, for example, for example, ammonia, hydrazine, methylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, butylamine, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, cyclohexylamine, aniline. , Tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, pyridine, N, N-dimethyl-4-aminopyridine, ammonium carbonate, ammonium hydrogencarbonate, Examples thereof include diammonium hydrogen phosphate.

The solvent of the alkaline solution may be either water or an organic solvent, but it is preferably a polar solvent (a polar organic solvent such as water or alcohol), and more preferably an aqueous solvent containing at least water.

The pH of the alkaline solution at 25 ° C. is preferably 9 or higher, more preferably 10 or higher, and particularly preferably 11-14. When the pH is 9 or more, the yield of microfiber cellulose is high. However, if the pH exceeds 14, the handleability of the alkaline solution deteriorates.

(Miniaturization (defibration) process)
For the refining treatment of the raw material fiber, for example, a beater, a high-pressure homogenizer, a homogenizer such as a high-pressure homogenizer, a millstone friction machine such as a grinder and a grinder, a single-screw kneader, a multi-screw kneader, a kneader refiner, etc. are used. This can be done by beating the raw material fibers. However, the miniaturization treatment is preferably performed using a refiner.

The refiner is a device for beating pulp fibers, and a known device can be used. As the refiner, a conical type, a double disc refiner (DDR) and a single disc refiner (SDR) are preferable from the viewpoints that a shearing force can be efficiently applied to the pulp fibers and preliminary defibration can be promoted. .. It is also preferable to use a refiner in the defibration treatment step from the viewpoint that separation and washing after the treatment are not required.

Microfiber cellulose (MFC) is a fiber made of cellulose or a derivative of cellulose. Ordinary microfiber cellulose has strong hydration property, and by hydrating in an aqueous medium, it stably maintains a dispersed state (state of a dispersion liquid). The single fibers constituting the microfiber cellulose may form a fibrous form by aggregating a plurality of strips in an aqueous medium.

The micronization (defibration) treatment is preferably carried out in a range in which the number average fiber diameter (fiber width; average diameter of single fibers) of the microfiber cellulose remains 0.1 μm or more, and is in a range of 0.1 to 15 μm. It is more preferable to carry out in the range of 0.2 to 10 μm, and it is particularly preferable to carry out in the range of 0.2 to 10 μm. By performing the process in the range where the number average fiber diameter (width) is 0.1 μm or more, dehydration by mixing the resin powder becomes possible, and the strength of the fibrous cellulose composite resin is improved.

Specifically, when the average fiber diameter is less than 0.1 μm, it is no different from that of cellulose nanofibers, and a sufficient reinforcing effect (particularly bending elastic modulus) cannot be obtained. In addition, the miniaturization processing time becomes long, a large amount of energy is required, which leads to an increase in manufacturing cost. Moreover, even if the resin powder is added as in this embodiment, dehydration becomes difficult and a large amount of energy is required for drying. On the other hand, when the average fiber diameter exceeds 15 μm, the dispersibility of the fibers tends to be inferior. If the dispersibility of the fibers is insufficient, the reinforcing effect is inferior.

The average fiber length (length of single fiber) of the microfiber cellulose is preferably 0.02 to 3.0 mm, more preferably 0.05 to 2.0 mm, and 0.1 to 1.5 mm. Is particularly preferable. If the average fiber length is less than 0.02 mm, a three-dimensional network of fibers cannot be formed, and the reinforcing effect may be significantly reduced. The average fiber length can be arbitrarily adjusted by, for example, selection of raw material fibers, pretreatment, and defibration treatment.

In the present embodiment, the fiber length of the microfiber cellulose is preferably 0.2 mm or less in a proportion of 12% or more, more preferably 16% or more, and particularly preferably 26% or more. If the ratio is less than 12%, a sufficient reinforcing effect may not be obtained. On the other hand, the fiber length of the microfiber cellulose has no upper limit of the ratio of 0.2 mm or less, and may be 0.2 mm or less in all cases.

The aspect ratio of the microfiber cellulose is preferably 2 to 30,000, more preferably 10 to 10000, in order to improve the mechanical strength while maintaining the ductility of the resin to some extent.

The aspect ratio is a value obtained by dividing the average fiber length by the average fiber width. It is considered that the larger the aspect ratio, the more places in the resin where the resin is caught, so that the reinforcing effect is improved, but on the other hand, the greater the number of catches, the lower the ductility of the resin.

In the present embodiment, the fibrillation rate of the microfiber cellulose is preferably 1.0% or more, more preferably 1.5% or more, and particularly preferably 2.0% or more. The fibrillation rate is preferably 30.0% or less, more preferably 20.0% or less, and particularly preferably 15.0% or less. If the fibrillation rate exceeds 30.0%, the miniaturization progresses too much and the cellulose nanofibers are formed, so that the intended effect may not be obtained. On the other hand, when the fibrillation rate is less than 1.0%, there are few hydrogen bonds between the fibrils, and a strong three-dimensional network becomes insufficient. In this regard, the present inventors have conducted various tests to construct a stronger three-dimensional network by hydrogen-bonding the fibrils of the microfiber cellulose to each other when the fibrillation rate of the microfiber cellulose is set to 1.0% or more. Found in the process. It was also found that increasing the fibrillation rate increases the interface in contact with the resin, but as described later, when a polybasic acid is used as a compatibilizer or for hydrophobic modification, the reinforcing effect is further improved. The method for measuring the fibrillation rate will be described later.

The crystallinity of the microfiber cellulose is preferably 50% or more, more preferably 55% or more, and particularly preferably 60% or more. When the crystallinity is less than 50%, the compatibility with the resin is improved, but the strength of the fiber itself is lowered, so that the reinforcing effect of the fibrous cellulose composite resin tends to be inferior.

On the other hand, the crystallinity of the microfiber cellulose is preferably 90% or less, more preferably 88% or less, and particularly preferably 86% or less. When the crystallinity exceeds 90%, the ratio of strong hydrogen bonds in the molecule increases and the fiber itself becomes rigid, but the compatibility with the resin decreases, and the reinforcing effect of the resin composition tends to be inferior. In addition, it tends to be difficult to chemically modify microfiber cellulose. The crystallinity can be arbitrarily adjusted by, for example, selection of raw material fibers, pretreatment, and miniaturization treatment.

The pulp viscosity of the microfiber cellulose is preferably 2 cps or more, and more preferably 4 cps or more. When the pulp viscosity is less than 2 cps, even if the resin powder is added to the microfiber cellulose, the aggregation of the microfiber cellulose cannot be sufficiently suppressed, and the reinforcing effect of the fibrous cellulose composite resin tends to be inferior.

The freeness of the microfiber cellulose is preferably 500 cc or less, more preferably 300 cc or less, and particularly preferably 100 cc or less. If it exceeds 500 cc, the fiber width of the microfiber cellulose exceeds 15 μm, and the reinforcing effect is not sufficient.

(Dispersion)
The microfiber cellulose obtained by the micronization treatment is dispersed in an aqueous medium to prepare a dispersion liquid. It is particularly preferable that the entire amount of the aqueous medium is water, but an aqueous medium which is another liquid which is partially compatible with water can also be preferably used. As the other liquid, lower alcohols having 3 or less carbon atoms can be used.

The dispersion is preferably concentrated to adjust the solid content concentration. The solid content concentration of this dispersion is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and particularly preferably 2.0% by mass or more. The solid content concentration of the dispersion is preferably 70% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less. If the solid content concentration is less than 1.0% by mass, the concentration may be lower than the concentration of the microfiber cellulose dispersion obtained by the micronization treatment. On the other hand, if the solid content concentration exceeds 70% by mass, it becomes difficult to dilute and disperse thereafter, and it may be difficult to mix with a polybasic acid, a resin powder, or other compositions.

In the microfiber cellulose of this embodiment, it is preferable that a part or all of the hydroxyl groups are modified with a polybasic acid, and this point will be described later.

(Addition of resin powder)
Next, the microfiber cellulose dispersion is mixed with a resin powder having an average particle size of 1 to 1500 μm. When the resin powder is mixed, the hydrogen bond between the dehydrated and dried microfiber celluloses is inhibited, and the dispersibility is improved. Further, in combination with the fact that the average fiber diameter of the microfiber cellulose is 0.1 μm or more, dehydration becomes possible, and the energy for drying can be greatly reduced. Therefore, the resin powder can be added at the time of concentrating the dispersion liquid described above.

The resin to be added may be, for example, a pellet-shaped resin, a sheet-shaped resin, or the like, but in this embodiment, a powdered resin (resin powder) is used. The types of resins that can be used are the same as in the case of resin pellets described later, and thus the description thereof will be omitted here.

The average particle size of the resin powder is preferably 1 to 1500 μm, more preferably 10 to 1200 μm, and particularly preferably 100 to 1000 μm. If the average particle size exceeds 1500 μm, the dispersibility and dehydration of the microfiber cellulose may not be improved. On the other hand, if the average particle size is less than 1 μm, the hydrogen bonds between the microfiber celluloses may not be inhibited due to the fineness, and the dispersibility may not be improved. Further, if the average particle size is less than 1 μm, the dehydration property may not be improved.

When the dehydration property of the microfiber cellulose is more important, the content (addition amount) of the resin powder is preferably 10 to 100,000 parts by mass and 50 to 10000 parts by mass with respect to 100 parts by mass of the microfiber cellulose. Is more preferable, and 100 to 1000 parts by mass is particularly preferable. If the content of the resin powder is less than 10 parts by mass, the dehydration property may not be sufficiently improved. On the other hand, if the content of the resin powder exceeds 100,000 parts by mass, the effect of containing the microfiber cellulose may not be obtained.

(Dehydration / drying)
The fibrous cellulose-containing material containing the microfiber cellulose and the resin powder is dried, preferably dehydrated and dried to obtain a fibrous cellulose dried product. Since the fibrous cellulose-containing material of this embodiment contains microfiber cellulose instead of cellulose nanofibers, it can be dehydrated. Moreover, since the fibrous cellulose-containing material of this embodiment contains a resin powder, dehydration can be easily performed. If dehydrated prior to drying, the energy required for drying will be extremely small. Further, since it contains resin powder, it is unlikely that the fibrous cellulose-containing material will not be dispersed even as a dried fibrous cellulose.

The microfiber cellulose of this embodiment may or may not be modified by a polybasic acid or the like. When modified with a polybasic acid, the water content (moisture content) of the dried fibrous cellulose (dehydrated / dried fibrous cellulose-containing material) is preferably 5% by mass or less, more preferably 3% by mass or less, and 1% by mass. % Or less is more preferable, and 0% by mass is particularly preferable. If the water content exceeds 5%, the microfiber cellulose may not be denatured by the polybasic acid. Further, if the water content is high, for example, when the fibrous cellulose dried product is kneaded next, the energy of the kneading becomes enormous, which is uneconomical.

On the other hand, when not modified by polybasic acid, the water content of the dehydrated / dried microfiber cellulose is preferably more than 5% by mass, more preferably 8% by mass or more, and particularly preferably 10% by mass or more. When the water content exceeds 5% by mass, the denaturation of the cellulose fibers by the polybasic acid does not proceed when the dried fibrous cellulose is then kneaded, and the obtained fibrous cellulose composite resin contains the polybasic acid. Will be.

For dehydration treatment, for example, select one or more from belt press, screw press, filter press, twin roll, twin wire former, valveless filter, center disk filter, membrane treatment, centrifuge and the like. Can be used.

The drying treatment includes, for example, rotary kiln drying, disk type drying, air flow type drying, medium flow drying, spray drying, drum drying, screw conveyor drying, paddle type drying, uniaxial kneading drying, multiaxial kneading drying, vacuum drying, stirring drying. One type or two or more types can be selected and used from the above.

After the dehydration / drying treatment, for example, a pulverization treatment may be performed. For the pulverization treatment, for example, one type or two or more types can be selected and used from among bead mills, kneaders, dispersers, twist mills, cut mills, hammer mills and the like.

The shape of the dehydrated / dried fibrous cellulose dried product can be powder, pellet, sheet or the like.

In the case of powder, the average particle size of the dried fibrous cellulose is preferably 1 to 10000 μm, more preferably 10 to 5000 μm, and particularly preferably 100 to 1000 μm. If the average particle size exceeds 10000 μm, it may not enter the kneading device because the particle size is large. On the other hand, if the average particle size is less than 1 μm, energy is required for the pulverization process, which is not economical.

When the dried fibrous cellulose is powdered, the bulk specific gravity is preferably 0.01 to 1.5, more preferably 0.04 to 1, and particularly preferably 0.1 to 0.5. If the bulk specific gravity exceeds 1.5, it means that the specific gravity of cellulose exceeds 1.5, which is physically difficult to realize. On the other hand, setting the bulk specific gravity to less than 0.01 is disadvantageous in terms of transfer cost.

(Kneading)
If necessary, resin pellets are added to the dried fibrous cellulose and kneaded to obtain a fibrous cellulose composite resin. When the resin pellets are not added, the fibrous cellulose dried product becomes a fibrous cellulose composite resin by simply applying heat or the like to knead. As described above, the description regarding the types of resin pellets in this embodiment also applies to the resin powder described above.

At the time of kneading or prior to kneading, it is preferable to further add a polybasic acid to modify the cellulose fibers with the polybasic acid, or to make the kneaded product contain the polybasic acid. As described above, the water content (moisture content) of the microfiber cellulose at the time of kneading is important.

As the resin, either a thermoplastic resin or a thermosetting resin can be used.

Examples of the thermoplastic resin include polyolefins such as polypropylene (PP) and polyethylene (PE), polyester resins such as aliphatic polyester resins and aromatic polyester resins, polyacrylic resins such as polystyrene, methacrylate and acrylate, and polyamide resins. One type or two or more types can be selected and used from polycarbonate resin, polyacetal resin and the like.

However, it is preferable to use at least one of polyolefin and polyester resin. Moreover, it is preferable to use polypropylene as the polyolefin. As the polypropylene, one type or two or more types can be selected and used from homopolymers, random polymers, and block polymers. Further, as the polyester resin, examples of the aliphatic polyester resin include polylactic acid and polycaprolactone, and examples of the aromatic polyester resin include polyethylene terephthalate, which are biodegradable. It is preferable to use a polyester resin having the above (also referred to simply as “biodegradable resin”).

As the biodegradable resin, for example, one or more of hydroxycarboxylic acid-based aliphatic polyester, caprolactone-based aliphatic polyester, dibasic acid polyester and the like can be selected and used.

As the hydroxycarboxylic acid-based aliphatic polyester, for example, homopolymers of hydroxycarboxylic acids such as lactic acid, malic acid, glucose acid, and 3-hydroxybutyric acid, and at least one of these hydroxycarboxylic acids are used together. One kind or two or more kinds can be selected and used from the polymer and the like. However, it is preferable to use polylactic acid, a copolymer of lactic acid and the above-mentioned hydroxycarboxylic acid excluding lactic acid, polycaprolactone, or a copolymer of at least one of the above-mentioned hydroxycarboxylic acids and caprolactone, and polylactic acid is used. It is particularly preferred to use.

As the lactic acid, for example, L-lactic acid, D-lactic acid and the like can be used, and these lactic acids may be used alone or two or more kinds may be selected and used.

As the caprolactone-based aliphatic polyester, for example, one or more can be selected and used from a homopolymer of polycaprolactone, a copolymer of polycaprolactone and the like and the above-mentioned hydroxycarboxylic acid, and the like. ..

As the dibasic acid polyester, for example, one or more of polybutylene succinate, polyethylene succinate, polybutylene adipate and the like can be selected and used.

As the biodegradable resin, one type may be used alone, or two or more types may be used in combination.

Examples of the thermosetting resin include phenol resin, urea resin, melamine resin, furan resin, unsaturated polyester, diallyl phthalate resin, vinyl ester resin, epoxy resin, urethane resin, silicone resin, thermosetting polyimide resin and the like. Can be used. These resins can be used alone or in combination of two or more.

The resin pellets may preferably contain an inorganic filler in a proportion that does not interfere with thermal recycling.

Examples of the inorganic filler include simple substances of metal elements in Groups I to VIII of the Periodic Table, such as Fe, Na, K, Cu, Mg, Ca, Zn, Ba, Al, Ti, and silicon elements, and oxidation. Examples thereof include substances, hydroxides, carbon salts, sulfates, silicates, sulfites, and various clay minerals composed of these compounds.

Specifically, for example, barium sulfate, calcium sulfate, magnesium sulfate, sodium sulfate, calcium sulfite, zinc oxide, silica, heavy calcium carbonate, light calcium carbonate, aluminum borate, alumina, iron oxide, calcium titanate, hydroxide. Examples of aluminum, magnesium hydroxide, calcium hydroxide, sodium hydroxide, magnesium carbonate, calcium silicate, clay walastonite, glass beads, glass powder, silica sand, silica stone, quartz powder, diatomaceous earth, white carbon, glass fiber and the like are exemplified. be able to. A plurality of these inorganic fillers may be contained. Further, it may be contained in used paper pulp.

As described above, it is possible not to use the resin pellets in obtaining the fibrous cellulose composite resin, but when the resin pellets are used, the content of the resin pellets is 1 to 1,000,000 when the resin powder is 100 parts by mass. The amount is preferably 10 to 100,000 parts by mass, and more preferably 10 to 100,000 parts by mass. Relatively, when the amount of resin powder increases (when the amount of resin pellets decreases), the bulk specific gravity tends to increase, so that the discharge amount in the kneader tends to decrease. On the other hand, when the amount of resin powder is small (the number of resin pellets is large), the dispersibility and dehydration of microfiber cellulose in the resin tend to decrease.

The blending ratio of the microfiber cellulose and the entire resin (resin powder or resin powder and resin pellets) is preferably 10 to 100,000 parts by mass, preferably 100 to 10000 parts by mass, when 100 parts by mass of the fibrous cellulose is used. Is more preferable. When the blending ratio is within the above range, the strength of the fibrous cellulose composite resin, particularly the bending strength and the tensile elastic modulus, can be remarkably improved, and the manufacturing cost can be reduced because of the excellent dehydration property. it can. The content ratio of the microfiber cellulose and the resin contained in the finally obtained fibrous cellulose composite resin is usually the same as the blending ratio of the microfiber cellulose and the resin used in the production.

(Polybasic acid)
Here, a description of polybasic acid will be added.
When modifying microfiber cellulose, examples thereof include hydrophobic modification such as esterification, etherification, amidation, and sulfidation. However, as a method for hydrophobically modifying microfiber cellulose, esterification is preferably adopted.

As a method of esterification, for example, esterification with a hydrophobic agent such as carboxylic acid, carboxylic acid halide, acetic acid, propionic acid, acrylic acid, methacrylic acid, phosphoric acid, sulfonic acid, polybasic acid anhydride and derivatives thereof. Can be mentioned. However, as the hydrophobic agent, it is preferable to use a polybasic acid such as anhydrous polybasic acid or a derivative thereof.

One preferable form of modifying the cellulose fiber with polybasic acid is a method of substituting a part or all of the hydroxyl groups of the cellulose fiber with the functional group represented by the following structural formula (1) or structural formula (2).

R in the structural formula is a linear, branched or cyclic saturated hydrocarbon group or an inducing group thereof; a linear, branched or cyclic unsaturated hydrocarbon group or an inducing group thereof; Either an aromatic group or an inducing group thereof;

Examples of the polybasic acid that undergoes such denaturation include oxalic acid, phthalic acid, malonic acid, succinic acid, glutamic acid, adipic acid, tartaric acid, glutamic acid, sebacic acid, hexafluorosilicic acid, maleic acid, and itaconic acid. One or more can be selected and used from acids, citraconic acids, citric acids and the like. However, it is preferable that at least one or more of phthalic acid, phthalates and derivatives of these (phthalates) are used.

Examples of phthalates (derivatives) include phthalic acid, potassium hydrogen phthalate, sodium hydrogen phthalate, sodium phthalate, ammonium phthalate, dimethyl phthalate, diethyl phthalate, diallyl phthalate, diisobutyl phthalate, and dinormal hexyl phthalate. , Dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, ditriisodecyl phthalate and the like. Preferably, phthalic acid is used.

As the anhydrous polybasic acids, for example, one or more of maleic anhydride, phthalic anhydride, itaconic anhydride, citraconic anhydride, citric acid anhydride and the like can be selected and used. However, it is preferable to use maleic anhydride, and more preferably phthalic anhydride.

Examples of phthalic anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hydroxyphthalic anhydride, hexahydrophthalic anhydride, 4-ethynylphthalic anhydride, and 4-phenylethynyl. Phthalic anhydride can be mentioned. However, it is preferable to use phthalic anhydride.

When polybasic anhydride is used, when the cellulose fiber is modified, a part of the hydroxyl group is replaced by a predetermined functional group, and the compatibility between the microfiber cellulose and the resin is improved.

On the other hand, when the cellulose fiber is not denatured by the polybasic acid and the polybasic acid is simply contained, the polybasic acid functions as a compatibilizer and the compatibility is improved. As a result, the strength of the obtained fibrous cellulose composite resin, particularly the bending strength, is improved.

When the polybasic acid functions as a compatibilizer, the progress of denaturation of the cellulose fibers does not matter, so that the quality of the obtained fibrous cellulose composite resin is stabilized. However, care must be taken not to denature the cellulose fibers by paying attention to the water content of the microfiber cellulose during kneading (this point is as described above).

As the anhydrous polybasic acid, it is preferable to use one having the following structural formula (3) or structural formula (4) in both the case of modifying the cellulose fiber and the case of simply containing it.

R in the structural formula is a linear, branched or cyclic saturated hydrocarbon group or an inducing group thereof; a linear, branched or cyclic unsaturated hydrocarbon group or an inducing group thereof; Either an aromatic group or an inducing group thereof;

By using the anhydrous polybasic acid represented by the structural formula (3) or the structural formula (4), the compatibility of the microfiber cellulose and the resin is improved.

The blending mass ratio of the polybasic acid in the solid content is preferably 0.1 to 50% by mass, preferably 1 to 30% by mass, regardless of whether the polybasic acid is used for denaturation or simply contained. Is more preferable, and 2 to 20% by mass is particularly preferable.

For the kneading process, for example, one or more types are selected and used from a single-screw or two-screw or more multi-screw kneader, a mixing roll, a kneader, a roll mill, a Banbury mixer, a screw press, a disperser, and the like. be able to. Among them, it is preferable to use a multi-screw kneader having two or more shafts. One or more multi-axis kneaders having two or more axes may be used in parallel or in series.

The peripheral speed of the screw of the multi-screw kneader having two or more shafts is preferably 0.2 to 200 m / min, more preferably 0.5 to 150 m / min, and particularly preferably 1 to 100 m / min. If the peripheral speed is less than 0.2 m / min, the microfiber cellulose cannot be dispersed well in the resin. On the other hand, when the peripheral speed exceeds 200 m / min, the shearing force on the microfiber cellulose becomes excessive and the reinforcing effect cannot be obtained.

The ratio of the screw diameter of the kneader used in this embodiment to the length of the kneading portion is preferably 15 to 60. If the ratio is less than 15, the kneaded portion is short and there is a possibility that the microfiber cellulose and the resin cannot be mixed. If the ratio exceeds 60, the kneaded portion is too long, so that the shear load and the heat load on the microfiber cellulose become high, and the reinforcing effect may not be obtained.

The temperature of the kneading treatment is equal to or higher than the glass transition point of the resin and varies depending on the type of resin, but is preferably 80 to 280 ° C, more preferably 90 to 260 ° C, and 100 to 240 ° C. Is particularly preferable.

At the time of kneading, polypropylene maleic anhydride may be added. The amount of polypropylene maleic anhydride added is preferably 1 to 1000 parts by mass, more preferably 5 to 500 parts by mass, and particularly preferably 10 to 200 parts by mass, with the blending amount of microfiber cellulose as 100 parts by mass. If the amount added is less than 1 part by mass, the effect is insufficient. On the other hand, if the amount added exceeds 1000 parts by mass, the amount added may be excessive, and conversely, the strength of the resin matrix may be lowered.

At the time of kneading, amines may be added as a method of adjusting the pH of the microfiber cellulose slurry. Examples of amines include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, triethanolamine, N, N-dimethylpropane-2-amine, tetramethylethyleneamine, hexamethylamine, spermidine, and spermin. , Amantazine, aniline, phenethylamine, toluidine, catecholamine, 1,8-bis (dimethylamino) naphthalene, pyrrolidine, piperidine, piperazine, morpholin, quinuclidine, pyrrol, pyrazole, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, oxazole, thiazole, 4-Dimethylaminopyridine and the like can be exemplified.

The amount of amines added is preferably 1 to 1000 parts by mass, more preferably 5 to 500 parts by mass, and particularly preferably 10 to 200 parts by mass, with the blending amount of microfiber cellulose as 100 parts by mass. If the amount added is less than 1 part by mass, the pH adjustment is insufficient. On the other hand, if the amount added exceeds 200 parts by mass, the amount added may be excessive, and conversely, the strength of the resin matrix may be lowered.

Examples of the solvent for hydrophobic modification of microfiber cellulose include no solvent (no solvent is used), protic polar solvent, aprotic polar solvent, non-polar solvent, resin and the like. However, it is preferable to use a resin as the solvent, and in this embodiment, the solvent is substantially unnecessary because it is modified when kneaded with the resin.

As the protic polar solvent, formic acid, butanol, isobutanol, nitromethane, ethanol, methanol, acetic acid, water and the like can be used, for example.

As the aprotic polar solvent, for example, N-methylpyrrolidone, tetrahydrofuran, ethyl acetate, acetone, dimethylformamide, acetonitrile, dimethyl sulfoxide, propylene carbonate and the like can be used.

As the non-polar solvent, for example, hexane, benzene, toluene, chloroform, diethyl ether, dichloromethane, etc. can be used.

The difference between the solubility parameters (cal / cm ³ ) ^1/2 (SP value) of _{microfiber cellulose and resin is the SP MFC} value of microfiber cellulose and the SP _POL value of resin, and the difference of SP value = SP _{MFC value-} It can be an SP _{POL value.} The difference in SP value is preferably 0.1 to 10, more preferably 0.5 to 8, and particularly preferably 1 to 5. If the difference in SP value exceeds 10, the microfiber cellulose is not dispersed in the resin, and the reinforcing effect cannot be obtained. On the other hand, if the difference in SP value is less than 0.1, the microfiber cellulose dissolves in the resin and does not function as a filler, so that a reinforcing effect cannot be obtained. _{In this respect, the smaller the difference between the SP POL} value of the resin (solvent) _{and the SP MFC} value of the microfiber cellulose (solute), the greater the reinforcing effect. The solubility parameter (cal / cm ³ ) ^1/2 (SP value) is a measure of the intermolecular force acting between the solvent and the solute, and the closer the SP value is to the solvent and solute, the higher the solubility. ..

(Other raw materials)
Microfiber cellulose includes one or more of various fine fibers called cellulose nanofibers, microfibril cellulose, microfibril-like fine fibers, microfiber cellulose, microfibrillated cellulose, super microfibril cellulose and the like. Can be included, and these fine fibers may be included. Further, it is also possible to include fibers in which these fine fibers are further refined, and may be contained. However, it is necessary to make the ratio of microfiber cellulose in all raw material fibers 10% by mass or more, preferably 30% by mass or more, and more preferably 60% by mass or more.

In addition to the above, kenaf, jute hemp, Manila hemp, sisal hemp, goose bark, sansho, cypress, banana, pineapple, coco palm, corn, sugar cane, bagasse, palm, papyrus, reed, esparto, survivorgrass, wheat, rice, bamboo, Fibers derived from plant materials obtained from various plants such as various conifers (such as sugi and cypress), broad-leaved trees and cotton may be included, and may be included.

As the raw material of the fibrous cellulose composite resin, in addition to microfiber cellulose and resin, for example, one or more kinds from antistatic agents, flame retardants, antibacterial agents, colorants, radical scavengers, foaming agents and the like are used. It can be selected and used as long as the effect of the present invention is not impaired.

These raw materials may be mixed with a dispersion of microfiber cellulose, kneaded at the time of kneading the dried fibrous cellulose and resin pellets, kneaded with these kneaded products, or other methods. You may knead with. However, from the viewpoint of production efficiency, it is preferable to knead the dried fibrous cellulose and the resin pellets at the same time.

The resin may contain an ethylene-α-olefin copolymer elastomer or a styrene-butadiene block copolymer. Examples of α-olefins include butene, isobutene, pentene, hexene, methyl-pentene, octene, decene, dodecene and the like.

(Molding process)
If necessary, the kneaded product of the dried fibrous cellulose body and the resin pellets may be kneaded again and then molded into a desired shape to obtain a fibrous cellulose composite resin. Even if the modified microfiber cellulose is dispersed in the kneaded product, the molding processability is excellent.

The size, thickness, shape, etc. of the molding are not particularly limited, and may be, for example, a sheet shape, a pellet shape, a powder shape, a fibrous shape, or the like.

The temperature during the molding process is equal to or higher than the glass transition point of the resin and varies depending on the type of resin, but is preferably 80 to 280 ° C, more preferably 90 to 260 ° C, and 100 to 240 ° C. It is particularly preferable to do so.

As the molding processing device, for example, one or more types from injection molding machines, blow molding machines, hollow molding machines, blow molding machines, compression molding machines, extrusion molding machines, vacuum molding machines, pressure molding machines, and the like. Can be selected and used.

The molding process can be performed by a known molding method, for example, mold molding, injection molding, extrusion molding, hollow molding, foam molding, or the like. It is also possible to spin the kneaded product into a fibrous form and mix it with the above-mentioned plant material or the like to form a mat shape or a board shape. The mixed fiber can be produced by, for example, a method of simultaneously depositing with an air ray.

In addition, this molding process can be performed after the kneading process, or the kneaded product is once cooled and made into chips by using a crusher or the like, and then the chips are used in a molding machine such as an extrusion molding machine or an injection molding machine. It can also be thrown in.

(Definition of terms, measurement method, etc.)
Unless otherwise specified, the terms in the specification are as follows.

(Average fiber diameter)
100 ml of an aqueous dispersion of microfiber cellulose having a solid content concentration of 0.01 to 0.1% by mass is filtered through a membrane filter manufactured by Teflon (registered trademark), and the solvent is replaced once with 100 ml of ethanol and three times with 20 ml of t-butanol. .. Next, it is freeze-dried and coated with osmium to prepare a sample. This sample is observed by an electron microscope SEM image at a magnification of 5000 times, 10000 times, or 30000 times depending on the width of the constituent fibers. Specifically, two diagonal lines are drawn on the observation image, and three straight lines passing through the intersections of the diagonal lines are arbitrarily drawn. Further, the width of a total of 100 fibers intersecting with these three straight lines is visually measured. Then, the median diameter of the measured value is taken as the average fiber diameter.

(Average fiber length / fibrillation rate)
The average fiber length and the fibrillation rate are measured by a fiber analyzer "FS5" manufactured by Valmet.

(aspect ratio)
It is a value obtained by dividing the average fiber length by the average fiber width (diameter).

(Crystallinity)
It is a value measured by an X-ray diffraction method in accordance with the "general rule of X-ray diffraction analysis" of JIS-K0131 (1996). The microfiber cellulose has an amorphous portion and a crystalline portion, and the crystallinity means the ratio of the crystalline portion to the entire microfiber cellulose.

(Pulp viscosity)
Measure according to JIS-P8215 (1998). The higher the pulp viscosity, the higher the degree of polymerization of the microfiber cellulose.

(Freeness)
It is a value measured according to JIS P8121-2: 2012.

(Moisture content (moisture content))
The water content of the fiber is a value calculated by the following formula, with the mass at the time when the sample is held at 105 ° C. for 6 hours or more at 105 ° C. and no change in mass is observed using a constant temperature dryer as the mass after drying.
Fiber moisture content (%) = [(mass before drying-mass after drying) ÷ mass before drying] x 100

Next, examples of the present invention will be shown to clarify the effects of the present invention.

(Example 1)
To 365 g of the aqueous dispersion of microfiber cellulose having a solid content concentration of 2.75% by weight, 83 g of polypropylene resin powder was added to obtain No. 2 Filter paper was suction filtered for 30 minutes and dehydrated to obtain a fibrous cellulose-containing material.

The dehydrated fibrous cellulose dehydrated product (aggregate) was dried by heating at 105 ° C. to obtain a fine cellulose dried product. The water content of the dried fibrous cellulose was less than 10%. The dried fibrous cellulose and 7 g of phthalic acid were kneaded with a twin-screw kneader under the conditions of 180 ° C. and 200 rpm to obtain a fibrous cellulose composite resin. The obtained fibrous cellulose composite resin was cut into a cylinder having a diameter of 2 mm and a length of 2 mm with a pelleter, and injection-molded into a rectangular parallelepiped test piece (length 59 mm, width 9.6 mm, thickness 3.8 mm) at 180 ° C.

Table 1 shows the physical characteristics of the microfiber cellulose, the particle size of the resin powder, the amount of filtration during dehydration, and the blending ratios of the microfiber cellulose (MFC), the chemical (phthalic acid), and the resin powder.

A bending test was carried out on the obtained molded product of the fibrous cellulose composite resin. The results are shown in Table 1. The evaluation method of the bending test is as follows.

(Bending test)
The flexural modulus was measured according to JIS K7171: 2008. In the table, the evaluation results are shown according to the following criteria.
When the flexural modulus (magnification) of the composite resin is 1.5 times or more, assuming that the flexural modulus of the resin itself is 1.
When the flexural modulus (magnification) of the composite resin is less than 1.5 times, where the flexural modulus of the resin itself is 1.

(Examples 2 to 6 and Comparative Examples 1 to 8)
As shown in Table 1, the same test as in Example 1 was performed under various conditions. The results are shown in Table 1. The polybasic acid was basically added immediately before kneading.

(Example 7)
To 365 g of the aqueous dispersion of microfiber cellulose having a solid content concentration of 2.75% by weight, 10 g of polypropylene resin powder was added to obtain No. 2 Filter paper was suction filtered for 30 minutes and dehydrated to obtain a fibrous cellulose-containing material.

The dehydrated fibrous cellulose dehydrated product (aggregate) was dried by heating at 105 ° C. to obtain a fine cellulose dried product. The water content of the dried fibrous cellulose was less than 10%. The dried fibrous cellulose body, 7 g of phthalic acid, and 73 g of polypropylene pellets were kneaded with a twin-screw kneader at 180 ° C. and 200 rpm to obtain a fibrous cellulose composite resin. The obtained fibrous cellulose composite resin was cut into a cylinder having a diameter of 2 mm and a length of 2 mm with a pelleter, and injection-molded into a rectangular parallelepiped test piece (length 59 mm, width 9.6 mm, thickness 3.8 mm) at 180 ° C.

Table 2 shows the physical characteristics of the microfiber cellulose, the particle size of the resin powder, the amount of filtration during dehydration, and the blending ratios of the microfiber cellulose (MFC), the chemical (phthalic acid), and the resin powder.

A bending test was carried out on the obtained molded product of the fibrous cellulose composite resin. The results are shown in Table 2. The evaluation method of the bending test is as described above.

(Examples 8 to 9 and Comparative Examples 9 to 11)
As shown in Table 2, the same test as in Example 7 was carried out under various conditions. The results are shown in Table 2. The polybasic acid was basically added immediately before kneading.

The present invention can be used as a fibrous cellulose-containing material and a method for producing the same, a dried fibrous cellulose and a method for producing the same, and a fibrous cellulose composite resin and a method for producing the same.

Claims (10)

Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. Including
The blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose is 50 to 100,000.
A fibrous cellulose-containing material. The ratio of the fiber length of the microfiber cellulose to 0.2 mm or less is 12% or more.
The fibrous cellulose-containing product according to claim 1. The pulp viscosity of the microfiber cellulose is 2 cps or more.
The fibrous cellulose-containing product according to claim 1 or 2. The microfiber cellulose has been modified with a polybasic acid and / or
The fibrous cellulose-containing material contains a polybasic acid.
The fibrous cellulose-containing product according to any one of claims 1 to 3. Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. The fibrous cellulose-containing material containing 50 to 100,000 of the resin powder in an amount of 100 parts by mass of the microfiber cellulose is dried.
A dried fibrous cellulose body. Microfiber cellulose having an average fiber width of 0.1 to 15 μm, an average fiber length of 0.02 to 2.0 mm, and a fibrillation rate of 1.0 to 8.37%, and a resin powder having an average particle size of 125 to 1500 μm. A dried product containing a fibrous cellulose containing 50 to 100,000 of the resin powder in an amount of 100 parts by mass of the microfiber cellulose is kneaded.
A fibrous cellulose composite resin characterized by this. Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and the resin powder having an average particle size of 125 to 1500 μm are mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose is 50 to 100,000.
A method for producing a fibrous cellulose-containing product. Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and a resin powder having an average particle size of 125 to 1500 μm were mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose was 50 to 100,000 to obtain a fibrous cellulose-containing material.
This fibrous cellulose-containing material is concentrated so that the water content is 95% or less, and then dried.
A method for producing a dried fibrous cellulose product. Microfiber cellulose is obtained by defibrating the raw material pulp within a range where the average fiber width is 0.1 to 15 μm, the average fiber length is 0.02 to 2.0 mm, and the fibrillation rate remains 1.0 to 8.37%. Obtain the dispersion of
This dispersion and a resin powder having an average particle size of 125 to 1500 μm were mixed so that the blending ratio of the resin powder to 100 parts by mass of the microfiber cellulose was 50 to 100,000 to obtain a fibrous cellulose-containing material.
This fibrous cellulose-containing material was dried to obtain a fibrous cellulose dried product.
Knead this dried fibrous cellulose
A method for producing a fibrous cellulose composite resin. The dried fibrous cellulose and the resin pellets shall be kneaded.
The mixing ratio of the resin pellets to 100 parts by mass of the resin powder is 10 to 100,000 parts by mass.
The method for producing a fibrous cellulose composite resin according to claim 9.