JP7121576B2 - Method for producing fibrous cellulose composite resin and fibrous cellulose-containing material, and fibrous cellulose composite resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fibrous cellulose composite resin, a method for producing a fibrous cellulose-containing material, and a fibrous cellulose composite resin.

In recent years, attention has been focused on nanotechnology, which is aimed at miniaturizing substances to the nanometer level and obtaining new physical properties that are different from the conventional properties of substances. Cellulose nanofibers, which are produced from pulp, a cellulosic raw material, by chemical treatment, pulverization, etc., are excellent in strength, elasticity, thermal stability, etc. It is expected to be used for industrial applications such as fillers for chromatographic analysis equipment, fillers for compounding resins and rubbers, and compounding agents for cosmetics such as lipsticks, powdered cosmetics, and emulsified cosmetics. there is In addition, cellulose nanofiber has excellent water-based dispersibility, so it can be used as a viscosity-retaining agent for foods, cosmetics, paints, etc., as a reinforcing agent for food raw material dough, as a moisture-retaining agent, as a food stabilizer, as a low-calorie additive, as an emulsifier. It is also expected to be used in many applications such as a stabilizing aid.

At present, proposals have been made to use cellulose nanofibers, which are obtained by miniaturizing plant fibers, as reinforcing materials for resins. However, when cellulose nanofibers are used as a resin reinforcing material, the cellulose nanofibers irreversibly aggregate due to intermolecular hydrogen bonds derived from hydroxyl groups of polysaccharides. In addition, even if the kneading with the resin is attempted to proceed forcibly, the fibers are torn off and a sufficient three-dimensional network cannot be constructed in the resin. Therefore, even if 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 improve the dispersibility of cellulose fibers. However, as pointed out in the same document itself, the use of organic solvents causes problems such as a decrease in productivity and an increase in production costs. Also, if an organic solvent is used, the strength of the composite resin to which cellulose fibers are added may be insufficient. Furthermore, the same document states that cellulose fibers are homogenized into fine fibers having an average fiber diameter of 10 to 800 nm, and the homogenized treatment liquid is drained and dried, but the present inventors recognize that However, it is extremely difficult to remove (dehydrate) the processing liquid. If the dehydration is difficult, the energy required for subsequent drying becomes large.

Therefore, the proposal of Patent Document 2 is helpful. The proposal aims to reduce the transportation and storage costs of fine fibrous cellulose. In the same document, for this purpose, a dispersion of fine fibrous cellulose having an average fiber width of 2 nm to 200 nm is concentrated, and at this time, a predetermined flocculant is added to aggregate the fine fibrous cellulose. The fibrous cellulose dispersion is filtered to remove water. The method of this document does not require the use of an organic solvent, and in this respect it does not have the problem of Patent Document 1 above. However, the inventors of the present invention believe that dehydration is difficult even with the proposal of the document. Moreover, even if dehydration can be performed, the addition of a flocculant may impair the reinforcing effect of the composite resin.

Japanese Patent No. 5863269 Japanese Patent No. 6048504

The main problems to be solved by the present invention are a method for producing a fibrous cellulose composite resin with high strength, a method for producing a fibrous cellulose-containing material highly effective in reinforcing the composite resin, and a fibrous cellulose composite with high strength. It is to provide a resin.

In order to solve the above problems, the present inventors performed various treatments on cellulose nanofibers (cellulose fine fibers) and searched for a method of kneading cellulose nanofibers and a resin. In other words, various studies were conducted on the premise of using cellulose nanofibers. However, when cellulose nanofibers are combined with a resin, for example, even if hydrophobic modification is applied or a compatibilizer is used, the dispersibility of cellulose nanofibers in the resin is not sufficient. A sufficient reinforcing effect was not obtained because a sufficient three-dimensional network was not formed. However, in the course of the research, it was found that microfibrous cellulose has better dispersibility in resin than cellulose nanofiber as fibrous cellulose and forms a sufficient three-dimensional network in resin. It was found that it is possible to obtain a good reinforcing effect. Moreover, the inventors have also found that microfiber cellulose having a predetermined fiber width can be dehydrated, unlike cellulose nanofibers. Under such circumstances, the following means have been conceived to solve the above problems.

(Means according to claim 1)
A dispersion of microfiber cellulose is obtained by fibrillating raw material fibers in a range in which the average fiber width is 0.1 μm or more and the fibrillation rate is 30% or less , the dispersion of microfiber cellulose is dried, and a resin is added. is a method of kneading by
Prior to drying the microfiber cellulose dispersion, dehydration is performed until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A method for producing a fibrous cellulose composite resin, characterized by:

(Means according to claim 2)
The defibration is performed so that the water retention of the microfiber cellulose is 380% or less,
The method for producing the fibrous cellulose composite resin according to claim 1.

(Means according to claim 3)
The fibrillation is performed so that the fibrillation rate of the microfiber cellulose is 1% or more,
The method for producing the fibrous cellulose composite resin according to claim 1 or 2.

(Means according to claim 4)
adding resin powder to the microfiber cellulose dispersion prior to dehydration of the microfiber cellulose dispersion;
and using resin pellets as the resin added after dehydration and drying of the microfiber cellulose dispersion.
A method for producing a fibrous cellulose composite resin according to any one of claims 1 to 3.

(Means according to claim 5)
adding resin powder to the microfiber cellulose dispersion prior to dehydration of the microfiber cellulose dispersion;
and no resin is added after dehydration and drying of the microfiber cellulose dispersion.
A method for producing a fibrous cellulose composite resin according to any one of claims 1 to 3.

(Means according to claim 6)
A method of defibrating raw material fibers in a range where the average fiber width is 0.1 μm or more and the fibrillation rate is 30% or less to obtain a dispersion of microfiber cellulose, and drying the dispersion of microfiber cellulose,
Prior to drying the microfiber cellulose dispersion, dehydration is performed until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A method for producing a fibrous cellulose-containing material, characterized by:

(Means according to claim 7)
A fibrous cellulose content obtained by drying a dispersion of microfiber cellulose having an average fiber width of 0.1 μm or more and a fibrillation rate of 30% or less , and a resin,
The fibrous cellulose-containing material is dehydrated prior to drying the microfiber cellulose dispersion until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A fibrous cellulose composite resin characterized by:

According to the present invention, there are provided a method for producing a fibrous cellulose composite resin with high strength, a method for producing a fibrous cellulose-containing material highly effective in reinforcing the composite resin, and a fibrous cellulose composite resin with high strength.

Next, a mode for carrying out the invention will be described. Note that the present embodiment 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 method of this embodiment can be mainly classified into the following two methods. On the other hand, first, the raw material fibers are fibrillated in a range in which the average fiber width remains at 0.1 μm or more, and a dispersion of microfiber cellulose (the water content of this dispersion is not particularly limited, and a water-containing (including cases where the ratio is low), and after dehydrating and drying this microfiber cellulose dispersion, a resin is added and kneaded to form a fibrous cellulose composite resin. On the other hand, the raw material fibers are fibrillated in a range in which the average fiber width remains at 0.1 μm or more to obtain a dispersion of microfiber cellulose, resin powder is added to the dispersion of microfiber cellulose, dehydrated and dried. The mixture is kneaded as it is, or if necessary, resin pellets are further added and kneaded to form a fibrous cellulose composite resin. Unless otherwise specified, the following description applies to both methods, and if it applies to only one method, it will be stated accordingly.

(Raw material fiber)
Microfiber cellulose having an average fiber width of 0.1 μm or more can be obtained by subjecting raw material fibers to a finer (defibration) treatment. As the raw material fibers, one or more of plant-derived fibers, animal-derived fibers, microorganism-derived fibers, and the like can be selected and used. However, it is preferable to use pulp fibers (raw material pulp) that are vegetable fibers. If the raw material fiber is pulp fiber, it is inexpensive and can avoid the problem of thermal recycling.

Plant-derived fibers include 1 from wood pulp made from broad-leaved trees, conifers, etc., non-wood pulp made from straw, bagasse, etc., and waste paper pulp (DIP) made from recycled waste paper, waste paper, etc. A species or two or more species can be selected and used.

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

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

The waste paper pulp (DIP) may be magazine waste paper pulp (MDIP), newspaper waste paper pulp (NDIP), corrugated waste paper pulp (WP), or other waste paper pulp. good.

Furthermore, as mechanical pulp, for example, stone ground pulp (SGP), pressure stone ground pulp (PGW), refiner ground pulp (RGP), chemi ground pulp (CGP), thermo ground pulp (TGP), ground pulp (GP ), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP), bleached thermomechanical pulp (BTMP), and the like. .

(Preprocessing)
The raw fibers are preferably pretreated by a chemical method prior to defibration. Pretreatment by a chemical method prior to the refining (fibrillation) treatment can significantly reduce the number of refining treatments and significantly reduce the energy required for the refining treatment.

Pretreatments by chemical methods include hydrolysis of polysaccharides by acid (acid treatment), hydrolysis of polysaccharides by enzymes (enzyme treatment), swelling of polysaccharides by alkali (alkali treatment), and oxidation of polysaccharides by oxidants (oxidation treatment). ), reduction of polysaccharides with a reducing agent (reduction treatment), and the like.

By performing alkali treatment prior to the refining process, some of the hydroxyl groups of the hemicellulose and cellulose that the pulp possesses are dissociated, and the molecules are anionized, weakening the intramolecular and intermolecular hydrogen bonds. It has the effect of promoting the dispersion of

Examples of the alkali include organic alkalis such as sodium hydroxide, lithium hydroxide, potassium hydroxide, aqueous ammonia solution, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and benzyltrimethylammonium hydroxide. However, it is preferable to use sodium hydroxide from the viewpoint of manufacturing cost.

If enzymatic treatment, acid treatment, or oxidation treatment is performed prior to pulverization treatment, the water retention of the microfiber cellulose can be lowered, the degree of crystallinity can be increased, and the homogeneity can be enhanced. In this regard, it is thought that the lower the water retention 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 fibrous cellulose composite resin to break. It is considered that a high-strength fibrous cellulose composite resin capable of retaining the ductility of the resin can be obtained. In addition, enzymatic treatment, acid treatment, and oxidation treatment decompose the hemicellulose and amorphous regions of cellulose in the pulp. As a result, the energy required for the refining process can be reduced, and the homogeneity and dispersibility of the fibers can be improved. be able to. In addition, when the ratio of the cellulose crystal region, which is considered to be rigid and low in water retention due to the alignment of the molecular chains, to the entire fiber increases, the dispersibility improves and the aspect ratio decreases, but the ductility is maintained. A fibrous cellulose composite resin having high mechanical strength can be obtained.

Among the various treatments described above, it is preferable to perform enzyme treatment, and in addition, it is more preferable to perform one or more treatments selected from acid treatment, alkali treatment, and oxidation treatment. The alkali treatment will be described in detail below.

As a method of alkali treatment, for example, there is a method of immersing raw fibers in an alkali solution.

The alkaline compound contained in the alkaline solution may be an inorganic alkaline compound or an organic alkaline compound. Examples of inorganic alkali compounds include hydroxides of alkali metals or alkaline earth metals, carbonates of alkali metals or alkaline earth metals, phosphate salts of alkali metals or alkaline earth metals, and the like. Examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, and the like. Examples of hydroxides of alkaline earth metals include calcium hydroxide. Examples of alkali metal carbonates include lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, and the like. Examples of carbonates of alkaline earth metals include calcium carbonate. Examples of alkali metal phosphates include lithium phosphate, potassium phosphate, trisodium phosphate, and disodium hydrogen phosphate. Examples of alkaline earth metal phosphates include calcium phosphate and calcium hydrogen phosphate.

Examples of organic alkali compounds include ammonia, aliphatic amines, aromatic amines, aliphatic ammoniums, aromatic ammoniums, heterocyclic compounds and their hydroxides, carbonates and phosphates. Specifically, 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 hydrogen carbonate, Diammonium hydrogen phosphate and the like can be exemplified.

The solvent of the alkaline solution may be either water or an organic solvent, preferably a polar solvent (water, a polar organic solvent such as alcohol), 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. A pH of 9 or higher results in a higher yield of microfibrous cellulose. However, if the pH exceeds 14, the handleability of the alkaline solution deteriorates.

(Refinement (fibrillation) treatment)
For example, the raw material fiber is refined by using a beater, a high-pressure homogenizer, a homogenizer such as a high-pressure homogenizer, a grinder, a millstone friction machine such as a grinder, a single-screw kneader, a multi-screw kneader, a kneader refiner, etc. It can be carried out by beating the raw material fiber with. However, it is preferred that the refinement treatment be performed using a refiner.

A 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 because they can efficiently impart a shearing force to pulp fibers and advance preliminary fibrillation. . It is preferable to use a refiner in the refinement treatment because it eliminates the need for separation and washing after the treatment.

Microfiber cellulose (MFC) is a fiber made of cellulose or a derivative of cellulose. Ordinary microfiber cellulose has a strong hydration property and stably maintains a dispersed state (dispersion state) by being hydrated in an aqueous medium. The single fibers that constitute the microfiber cellulose may sometimes form a fibrous form in which multiple strands are aggregated in an aqueous medium.

The refining (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 at 0.1 μm or more, and is in the range of 0.1 to 15 μm. It is more preferable to carry out in the range of 0.2 to 10 μm. When the number average fiber diameter (width) is within a range of 0.1 μm or more, dehydration becomes possible unlike cellulose nanofibers, and the strength of the fibrous cellulose composite resin is improved.

Specifically, if the average fiber diameter is less than 0.1 μm, it is no different from cellulose nanofibers, and a sufficient reinforcing effect (especially bending elastic modulus) cannot be obtained. In addition, the time required for the miniaturization process is long, and a large amount of energy is required, leading to an increase in manufacturing costs. Moreover, even if resin powder is added, dehydration becomes difficult, and a large amount of energy is required for drying. If a large amount of energy is applied to drying, the microfiber cellulose will be thermally degraded, leading to a decrease in the reinforcing effect. On the other hand, when the average fiber diameter exceeds 15 μm, the dispersibility of the fibers tends to be poor. If the dispersibility of the fibers is insufficient, the reinforcing effect is inferior.

The average fiber length (length of single fiber) of 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 preferred. If the average fiber length is less than 0.02 mm, a three-dimensional network cannot be formed between the fibers, and there is a risk that the reinforcing effect will be significantly reduced. The average fiber length can be arbitrarily adjusted by, for example, selection of raw material fibers, pretreatment, and fibrillation treatment.

In this embodiment, the fiber length of 0.2 mm or less in the microfiber cellulose is preferably 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 microfiber cellulose does not have an upper limit on the proportion of 0.2 mm or less, and may all be 0.2 mm or less.

The aspect ratio of the microfiber cellulose is preferably 2 to 30,000, more preferably 10 to 10,000, 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 thought that the greater the aspect ratio, the greater the number of locations in the resin where catching occurs, thus increasing the reinforcing effect, but on the other hand, the greater the catching, the less the ductility of the resin. There is knowledge that when an inorganic filler is kneaded with a resin, the tensile strength increases as the aspect ratio of the inorganic filler increases, but the tensile elongation at break decreases significantly.

In this 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. Also, 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 contact area with water becomes too large, and even if the average fiber width is within the range of 0.1 μm or more, dehydration may become difficult. There is On the other hand, if the fibrillation rate is less than 1.0%, there are few hydrogen bonds between fibrils, resulting in a lack of a strong three-dimensional network. In this regard, the present inventors have found in various tests that when the fibrillation rate of the microfiber cellulose is 1.0% or more, the fibrils of the microfiber cellulose are hydrogen-bonded to each other to construct a stronger three-dimensional network. found in the process. In addition, the inventors have also found that, although increasing the fibrillation rate increases the interface contacting with the resin, the reinforcing effect is further improved by using polybasic acid as a compatibilizing agent or for hydrophobicity modification, as described later.

The crystallinity of the microfibrous cellulose is preferably 50% or higher, more preferably 55% or higher, particularly preferably 60% or higher. If the degree of crystallinity is less than 50%, the compatibility with the resin is improved, but the strength of the fiber itself is lowered, so the effect of reinforcing the fibrous cellulose composite resin tends to be poor.

On the other hand, the crystallinity of the microfibrous cellulose is preferably 90% or less, more preferably 88% or less, and especially preferably 86% or less. If the degree of crystallinity exceeds 90%, the proportion of strong hydrogen bonds in the molecule increases and the fiber itself becomes rigid, but the compatibility with the resin decreases and the effect of reinforcing the resin tends to be inferior. It also tends to make chemical modification of microfiber cellulose difficult. The degree of crystallinity can be arbitrarily adjusted by, for example, selection of raw material fibers, pretreatment, and refinement treatment.

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

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

The water retention of the microfibrous cellulose is preferably 380% or less, more preferably 360% or less, particularly preferably 330% or less. When the water retention exceeds 380%, dehydration, drying, and compatibility with resins tend to be poor. In addition, in order to make the reinforcing effect of the fibrous cellulose composite resin excellent, it is necessary to sufficiently dry the microfiber cellulose and uniformly disperse it in the resin. However, since microfiber cellulose has cohesiveness, there is a possibility of cohesion during drying, kneading with resin, or the like. Therefore, by making the water retention rate of microfiber cellulose 380% or less and making it excellent in dehydration, drying, and compatibility with resin, aggregation during drying processing and kneading processing with resin is suppressed. The reinforcing effect of the fibrous cellulose composite resin can be made sufficient. The water retention can be arbitrarily adjusted by the pulp fiber, the pretreatment process, and the pulverization process.

(dispersion liquid)
The microfiber cellulose obtained by the pulverization treatment is in the form of a dispersion, and if necessary, it is mixed with an aqueous medium to obtain a low-concentration dispersion. It is particularly preferable that the entire amount of the aqueous medium is water, but it is also possible to preferably use an aqueous medium that is partly another liquid that is compatible with water. Other liquids that can be used include lower alcohols having 3 or less carbon atoms.

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 exceeds 70% by mass, it may become difficult to mix with polybasic acid, resin powder, and other compositions. The solid content concentration of the dispersion of microfiber cellulose obtained by the pulverization treatment is usually 1.0 to 3.0% by mass.

The microfibrous cellulose of this form is preferred when some or all of the hydroxyl groups are modified with a polybasic acid, as will be discussed later.

(Addition of resin powder)
If necessary, resin powder is added to and mixed with the microfiber cellulose dispersion. When the resin powder is mixed, the hydrogen bonding between the dehydrated and dried microfiber cellulose is inhibited, and the dispersibility and redispersibility are improved. Also, when resin powder is mixed, the dehydration property is improved, and the drying energy can be greatly reduced. Therefore, the addition of the resin powder can also be carried out during the concentration of the dispersion described above.

The resin to be added may be, for example, a pellet-shaped resin or a sheet-shaped resin, but in this embodiment, a powder-shaped resin (resin powder) is used. Note that the types (components) of usable resins are the same as in the case of resin pellets, which will be described later, so descriptions thereof are omitted here.

The average particle size of the resin powder is preferably 1-1500 μm, more preferably 10-1200 μm, and particularly preferably 100-1000 μm. If the average particle size exceeds 1500 μm, the dispersibility/redispersibility and dehydration properties of the microfiber cellulose may not be sufficiently improved. On the other hand, if the average particle size is less than 1 μm, the fine particles may not be able to inhibit hydrogen bonding between microfiber celluloses, and the dispersibility and redispersibility may not be sufficiently improved. Moreover, when the average particle size is less than 1 μm, there is a possibility that dehydration properties are not improved.

When the dehydration property of microfiber cellulose is more important, the content (addition amount) of the resin powder is preferably 10 to 100000 parts by weight, more preferably 100 to 10000 parts by weight, with respect to 100 parts by weight of microfiber cellulose. is more preferable. If the resin powder content is less than 10 parts by mass, dehydration 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 inclusions comprising microfibrous cellulose or microfibrous cellulose and resin powder are dried and dewatered into fibrous cellulose dry matter. In addition, since this fibrous cellulose dry material contains microfiber cellulose, it can also be called a fibrous cellulose-containing material.

The fibrous cellulose-containing material of the present embodiment can be dehydrated because it contains not cellulose nanofibers but microfiber cellulose having an average fiber width of 0.1 μm or more. This dehydration property is further improved when the microfiber cellulose has a water retention rate of 380% or less, or a fibrillation rate of 1% or more, as described above. Furthermore, when the fibrous cellulose dry body (content) of the present embodiment contains resin powder, dehydration can be carried out more easily. If dehydration is performed prior to drying, the energy required for drying is extremely small, and heat deterioration of the microfiber cellulose is avoided, thereby improving the reinforcing effect of the resin. In addition, when the resin powder is contained, there is a low possibility that the microfiber cellulose dispersion liquid will not be redispersed even if it is made into a fibrous cellulose dry body.

Dehydration of the fibrous cellulose-containing material can be performed, for example, by centrifugal dehydration, vacuum dehydration, pressurized dehydration, or the like.

The fibrous cellulose-containing material, whether it contains resin powder or not, has a water content of 93% by mass or less, preferably 85 to 30% by mass, more preferably 75% by mass. Dehydrate to ~40 wt%. By dehydrating until the water content is 93% by mass or less, the volume and weight can be reduced, so the transportation energy to the next process can be reduced. Also, the energy required for subsequent drying can be reduced. However, dehydration to a moisture content of less than 30% by mass results in poor energy efficiency in the dehydration step, and it is preferable to achieve such a moisture content by drying.

The microfiber cellulose of this form may or may not be modified by polybasic acid or the like. When modified with a polybasic acid, the moisture content (moisture content) of the dried fibrous cellulose (dehydrated and 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 moisture content exceeds 5%, the polybasic acid may not denature the microfiber cellulose. Further, if the moisture content is high, for example, when kneading the dried fibrous cellulose, the kneading energy is enormous, which is not economical. Also, increased kneading energy can lead to thermal degradation of the microfiber cellulose, fiber breakage, and the like.

On the other hand, when not modified by polybasic acid, the moisture content of the dehydrated and dried microfiber cellulose dry body is preferably more than 5% by mass, more preferably 8% by mass or more, and particularly preferably 10% by mass or more. If the water content exceeds 5% by mass, the denaturation of the cellulose fibers by the polybasic acid will not progress when the dried fibrous cellulose is kneaded, and the resulting fibrous cellulose composite resin will contain the polybasic acid. become.

For the dehydration treatment, for example, one or more selected from belt press, screw press, filter press, twin roll, twin wire former, valveless filter, center disk filter, membrane treatment, centrifugal separator, etc. can be used.

Drying treatments include, for example, rotary kiln drying, disk drying, airflow drying, medium fluidized drying, spray drying, drum drying, screw conveyor drying, paddle drying, single-screw kneading drying, multi-screw kneading drying, vacuum drying, and stirring drying. 1 type or 2 or more types can be selected and used from among.

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

The shape of the dehydrated and dried fibrous cellulose dry material can be powder, pellet, sheet, or the like.

When powdered, the average particle size of the dried fibrous cellulose is preferably 1 to 10,000 μm, more preferably 10 to 5,000 μm, and particularly preferably 100 to 1,000 μm. If the average particle size exceeds 10,000 μm, the particles may not enter the kneading device due to the large particle size. On the other hand, if the average particle size is less than 1 μm, energy is required for pulverization, 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. A bulk specific gravity exceeding 1.5 means that the specific gravity of cellulose exceeds 1.5, which is physically difficult to achieve. On the other hand, setting the bulk specific gravity to less than 0.01 is disadvantageous in terms of transportation costs.

(kneading)
The dried fibrous cellulose is mixed with a resin and kneaded to form a fibrous cellulose composite resin. The resin added at this time is preferably in the form of pellets (resin pellets). Further, if resin powder is added to the microfiber cellulose prior to this step, addition of the resin here can be omitted. When the resin is not added in this step, the fibrous cellulose dry body becomes the fibrous cellulose composite resin by simply heating and kneading. In addition, as described above, the description regarding the types (components) of the resin, etc. in the present embodiment also applies to the resin powder described above.

During kneading or prior to kneading, it is preferable to 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 moisture content (moisture content) of the dried fibrous cellulose during kneading is important. Also, during the kneading, the mixture is usually degassed.

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

Examples of thermoplastic resins 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, methacrylates and acrylates, polyamide resins, One or more of polycarbonate resins, polyacetal resins and the like can be selected and used.

However, it is preferable to use at least one of polyolefin and polyester resin. Polypropylene is preferably used as the polyolefin. As polypropylene, one or more of homopolymers, random polymers, and block polymers can be selected and used. Furthermore, as polyester resins, aliphatic polyester resins such as polylactic acid and polycaprolactone can be exemplified, and aromatic polyester resins such as polyethylene terephthalate can be exemplified. It is preferable to use a polyester resin having

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

Hydroxycarboxylic acid-based aliphatic polyesters include, for example, homopolymers of hydroxycarboxylic acids such as lactic acid, malic acid, glucose acid, and 3-hydroxybutyric acid, and copolymers using at least one of these hydroxycarboxylic acids. One or two or more may be selected and used from among polymers and the like. However, it is preferable to use polylactic acid, a copolymer of lactic acid and the above hydroxycarboxylic acids other than lactic acid, polycaprolactone, and a copolymer of at least one of the above hydroxycarboxylic acids and caprolactone. It is particularly preferred to use

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

As the caprolactone-based aliphatic polyester, for example, one or more of polycaprolactone homopolymers and copolymers of polycaprolactone and the above hydroxycarboxylic acids can be selected and used. .

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.

A biodegradable resin may be used individually by 1 type, or may use 2 or more types together.

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

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

Examples of inorganic fillers 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; substances, hydroxides, carbonates, sulfates, silicates, sulfites, various clay minerals composed of these compounds, and the like.

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 include aluminum, magnesium hydroxide, calcium hydroxide, sodium hydroxide, magnesium carbonate, calcium silicate, clay wollastonite, glass beads, glass powder, silica sand, silica stone, quartz powder, diatomaceous earth, white carbon, and glass fiber. be able to. A plurality of these inorganic fillers may be contained. It may also be contained in waste paper pulp.

In obtaining the fibrous cellulose composite resin, when the resin is added in this step and the resin powder is added prior to this step, the amount of resin added in this step is 100% of the amount of resin powder added. When expressed as parts by mass, it is preferably from 1 to 10,000 parts by mass, more preferably from 10 to 1,000 parts by mass. Relatively, when the amount of resin powder increases (when the amount of resin in this step decreases), the bulk specific gravity tends to decrease, so there is a tendency for the production amount of the kneader to decrease. On the other hand, less resin powder (more resin in this step) tends to reduce the dispersibility and dehydration of the microfiber cellulose in the resin.

The mixing ratio of the microfiber cellulose and the entire resin (the resin or resin powder in this step and the resin or resin powder in this step) is 10 to 100,000 parts by mass based on 100 parts by mass of fibrous cellulose. is preferable, and 100 to 10,000 parts by mass is more preferable. When the blending ratio is within the above range, the strength of the fibrous cellulose composite resin, especially the bending strength and tensile elastic modulus, can be remarkably improved, and the production cost can be reduced because of excellent dehydration properties. The content ratio of the microfiber cellulose and the resin contained in the fibrous cellulose composite resin finally obtained is usually the same as the mixing ratio of the microfiber cellulose and the resin used in the production.

(polybasic acid)
Here, an explanation of polybasic acid is added.
When modifying the microfiber cellulose, the method can include, for example, hydrophobic modification such as esterification, etherification, amidation, sulfidation, and the like. However, it is preferable to employ esterification as a method for hydrophobically modifying the microfiber cellulose.

Examples of the esterification method include esterification with a hydrophobizing agent such as carboxylic acid, carboxylic acid halide, acetic acid, propionic acid, acrylic acid, methacrylic acid, phosphoric acid, sulfonic acid, polybasic anhydride, and derivatives thereof. can be mentioned. However, it is preferable to use a polybasic acid such as polybasic anhydride or a derivative thereof as the hydrophobizing agent.

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

構造式中のＲは、直鎖状、分枝鎖状、若しくは環状の飽和炭化水素基又はその誘導基；直鎖状、分枝鎖状、若しくは環状の不飽和炭化水素基又はその誘導基；芳香族基又はその誘導基；のいずれかである。

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

Examples of polybasic acids for such modification include oxalic acids, phthalic acids, malonic acids, succinic acids, glutaric acids, adipic acids, tartaric acids, glutamic acids, sebacic acids, hexafluorosilicic acids, maleic acids, itacon One or more of acids, citraconic acids, citric acids and the like can be selected and used. However, at least one of phthalic acid, phthalates, and derivatives thereof (phthalic acids) is preferred.

Phthalic acids (derivatives) include phthalic acid, potassium hydrogen phthalate, sodium hydrogen phthalate, sodium phthalate, ammonium phthalate, dimethyl phthalate, diethyl phthalate, diallyl phthalate, diisobutyl phthalate, and di-normalhexyl phthalate. , dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, ditriisodecyl phthalate, and the like. Preferably, phthalic acid is used.

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

Phthalic anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hydroxyphthalic anhydride, hexahydrophthalic anhydride, 4-ethynylphthalic anhydride, and 4-phenylethynyl Phthalic anhydride is mentioned. However, it is preferred to use phthalic anhydride.

The use of polyacid anhydrides, when modifying cellulose fibers, replaces some of the hydroxyl groups with certain functional groups, improving the compatibility of the microfiber cellulose and the resin.

On the other hand, when the polybasic acid is simply contained without modifying the cellulose fiber with the polybasic acid, the polybasic acid functions as a compatibilizing agent and the compatibility is improved. As a result, the strength of the resulting fibrous cellulose composite resin, especially bending strength, is improved.

When the polybasic acid functions as a compatibilizer, the degree of progress of modification of the cellulose fibers does not matter, so the quality of the resulting fibrous cellulose composite resin is stabilized. However, it is necessary to pay attention to the moisture content of the dried fibrous cellulose during kneading (this point is as described above) so as not to denature the cellulose fibers.

As the polybasic acid anhydride, it is preferable to use one represented by the following structural formula (3) or (4), regardless of whether the cellulose fiber is modified or simply contained.

構造式中のＲは、直鎖状、分枝鎖状、若しくは環状の飽和炭化水素基又はその誘導基；直鎖状、分枝鎖状、若しくは環状の不飽和炭化水素基又はその誘導基；芳香族基又はその誘導基；のいずれかである。

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

The compatibility of the microfiber cellulose and the resin is improved by using the polybasic anhydride having the above structural formula (3) or (4).

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

For the kneading treatment, for example, one or more selected from single-screw or multi-screw kneaders with two or more screws, mixing rolls, kneaders, roll mills, Banbury mixers, screw presses, dispersers, etc. are used. be able to. Among them, it is preferable to use a multi-screw kneader with two or more screws. One or more multi-screw kneaders with two or more screws may be used in parallel or in series.

The peripheral speed of the screws of the multi-screw kneader with two or more screws 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 well dispersed in the resin. On the other hand, when the peripheral speed exceeds 200 m/min, the shear force applied to 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 section is preferably 15-60. If the ratio is less than 15, the kneading section may be too short to mix the microfiber cellulose and the resin. If the ratio exceeds 60, the length of the kneading section is too long, which increases the shear load and thermal deterioration of the microfiber cellulose, possibly failing to obtain the reinforcing effect.

The temperature of the kneading treatment is 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 more preferably 100 to 240°C. is particularly preferred.

During kneading, polypropylene maleic anhydride may be added. The amount of maleic anhydride polypropylene to be 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 based on 100 parts by mass of microfiber cellulose. If the amount added is less than 1 part by mass, the effect is insufficient. On the other hand, if the amount added exceeds 1,000 parts by mass, it is excessively added, which may adversely reduce the strength of the resin matrix.

During 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-dimethylpropan-2-amine, tetramethylethyleneamine, hexamethylamine, spermidine, and spermine. , amantadine, aniline, phenethylamine, toluidine, catecholamine, 1,8-bis(dimethylamino)naphthalene, pyrrolidine, piperidine, piperazine, morpholine, quinuclidine, pyrrole, 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 based on 100 parts by mass of the microfiber cellulose. If the amount added is less than 1 part by mass, pH control is insufficient. On the other hand, if the added amount exceeds 200 parts by mass, it becomes an excessive addition, which may conversely reduce the strength of the resin matrix.

Solvents for hydrophobizing microfiber cellulose include no solvent (no solvent is used), protic polar solvents, aprotic polar solvents, nonpolar solvents, resins, and the like. However, it is preferable to use a resin as the solvent, and in the present embodiment, the resin is modified when kneaded, so the solvent can be substantially eliminated.

Examples of protic polar solvents that can be used include formic acid, butanol, isobutanol, nitromethane, ethanol, methanol, acetic acid, and water.

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

Examples of nonpolar solvents that can be used include hexane, benzene, toluene, chloroform, diethyl ether, dichloromethane, and the like.

If the difference in the solubility parameter (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, the difference in SP value = SP _MFC value - SP can be a _POL value. The SP value difference is preferably 0.1 to 10, more preferably 0.5 to 8, and particularly preferably 1 to 5. If the SP value difference exceeds 10, the microfiber cellulose will not be 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 will dissolve in the resin and will not function as a filler, failing to obtain a reinforcing effect. In this regard, 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 a solvent and a solute. Solvents and solutes with closer SP values have higher solubility. .

(Other raw materials)
Microfibrous cellulose includes one or more of various fine fibers called cellulose nanofiber, microfibril cellulose, microfibrillar fine fiber, microfiber cellulose, microfibrillated cellulose, super microfibril cellulose, and the like. can be included, and these fine fibers may also be included. In addition, it is also possible to include, or may include, fibers obtained by further miniaturizing these fine fibers. However, it is necessary that the proportion of microfiber cellulose in all raw material fibers is 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, ganpi, mitsumata, mulberry, banana, pineapple, coconut palm, corn, sugar cane, bagasse, palm, papyrus, reed, esparto, sabaigrass, barley, rice, bamboo, Fibers derived from plant materials obtained from various plants such as various coniferous trees (such as cedar and cypress), broad-leaved trees, and cotton can also be included, and may be included.

As raw materials for the fibrous cellulose composite resin, in addition to microfiber cellulose and resin, for example, one or more of antistatic agents, flame retardants, antibacterial agents, colorants, radical scavengers, foaming agents, etc. It can be selected and used within a range that does not impair the effects of the present invention.

These raw materials may be mixed with the microfiber cellulose (dispersion), kneaded together during the kneading of the dried fibrous cellulose and the resin, kneaded with these kneaded products, or by other methods. can be kneaded with However, from the viewpoint of production efficiency, it is preferable to knead the dried fibrous cellulose and the resin 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)
The dried fibrous cellulose and the kneaded resin can be kneaded again if necessary, and then molded into a desired shape to obtain a fibrous cellulose composite resin. Even when the modified microfiber cellulose is dispersed in the kneaded product, the kneaded product is excellent in moldability.

The size, thickness, shape, and the like of the molded product are not particularly limited, and may be, for example, sheet-like, pellet-like, powder-like, fibrous-like, 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 more preferably 100 to 240°C. is particularly preferred.

As the apparatus for molding treatment, for example, one or more of injection molding machines, blow molding machines, blow molding machines, blow molding machines, compression molding machines, extrusion molding machines, vacuum molding machines, air pressure molding machines, etc. can be selected and used.

The molding treatment can be performed by a known molding method, such as die molding, injection molding, extrusion molding, blow molding, foam molding, and the like. Alternatively, the kneaded product may be spun into a fibrous form and mixed with the above-described plant material or the like to form a mat or board. Mixing can be carried out by, for example, a method of simultaneous deposition by air laying.

This molding process may be carried out after the kneading process, or the kneaded material may be cooled once, chipped using a crusher or the like, and then the chips may be placed in a molding machine such as an extruder or an injection molding machine. You can also put it in.

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

(average fiber diameter)
100 ml of an aqueous dispersion of microfiber cellulose with a solid content concentration of 0.01 to 0.1% by mass is filtered through a Teflon (registered trademark) membrane filter, and the solvent is replaced once with 100 ml of ethanol and 3 times with 20 ml of t-butanol. . It is then freeze-dried and coated with osmium to form a sample. This sample is observed with an electron microscope SEM image at a magnification of 5,000, 10,000 or 30,000 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. Furthermore, 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 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 JIS-K0131 (1996) "General Rules for X-ray Diffraction Analysis". It should be noted that the microfiber cellulose has an amorphous portion and a crystalline portion, and the degree of crystallinity means the proportion of the crystalline portion in the entire microfiber cellulose.

(pulp viscosity)
Measure according to JIS-P8215 (1998). It should be noted that 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 moisture content of the fiber is a value calculated by the following formula, using a constant temperature dryer, holding the sample at 105° C. for 6 hours or more, and using the mass after drying as the mass when no change in mass is observed.
Fiber moisture content (%) = [(mass before drying - mass after drying) / mass before drying] x 100

(water retention)
JAPAN TAPPI NO. 26: 2000-based water retention measurement method.

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

(Example 1)
10 g of polypropylene powder was added to 500 g of a microfiber cellulose aqueous dispersion having a solid content concentration of 2% by mass. 2 filter paper for 10 minutes with suction filtration (dehydration) to obtain the microfiber cellulose inclusions.

The dehydrated microfiber cellulose aggregate was dried by heating at 105° C. to obtain a fibrous cellulose dry body. The moisture content of the dried fibrous cellulose was less than 10%. The dried fibrous cellulose, 7 g of phthalic acid, and 73 g of polypropylene pellets were kneaded in a twin-screw kneader at 180° C. and 200 rpm to obtain a fibrous cellulose composite resin. The resulting fibrous cellulose composite resin was cut into cylinders with a diameter of 2 mm and a length of 2 mm using a pelleter, and injection-molded at 180° C. into cuboid specimens (length 59 mm, width 9.6 mm, thickness 3.8 mm). .

Table 1 shows the physical properties of the microfiber cellulose, the particle size of the resin powder, the water content after dehydration, and the mixing ratio of the microfiber cellulose (MFC), the chemical (phthalic acid), the resin powder, and the resin pellets.

A bending test was performed on the obtained fibrous cellulose composite resin molding. The results are shown in Table 1. In addition, 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 bending elastic modulus of the resin itself is 1 and the bending elastic modulus (magnification) of the composite resin is 1.5 times or more: ○
When the bending elastic modulus of the resin itself is 1 and the bending elastic modulus (magnification) of the composite resin is 1.4 times or more and less than 1.5 times: △

If the bending elastic modulus (magnification) of the composite resin is less than 1.4 times the bending elastic modulus of the resin itself as 1: ×

(Other Examples and Comparative Examples)
For Examples 2 to 8 and Comparative Example 1, various conditions were changed as shown in Table 1, and the same tests as in Example 1 were performed. As for Comparative Example 2, a test was conducted in which dehydration was not performed as compared with Example 8, but drying was performed immediately. The results are shown in Table 1. The polybasic acid was basically added just before kneading. As for the result of Comparative Example 2, although the reason is not clear, it is considered that the material was thermally deteriorated due to the long drying time, and sufficient strength was not obtained.

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

Claims (7)

A dispersion of microfiber cellulose is obtained by fibrillating raw material fibers in a range in which the average fiber width is 0.1 μm or more and the fibrillation rate is 30% or less , the dispersion of microfiber cellulose is dried, and a resin is added. is a method of kneading by
Prior to drying the microfiber cellulose dispersion, dehydration is performed until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A method for producing a fibrous cellulose composite resin, characterized by: The defibration is performed so that the water retention of the microfiber cellulose is 380% or less,
The method for producing the fibrous cellulose composite resin according to claim 1. The fibrillation is performed so that the fibrillation rate of the microfiber cellulose is 1% or more,
The method for producing the fibrous cellulose composite resin according to claim 1 or 2. adding resin powder to the microfiber cellulose dispersion prior to dehydration of the microfiber cellulose dispersion;
and using resin pellets as the resin added after dehydration and drying of the microfiber cellulose dispersion.
A method for producing a fibrous cellulose composite resin according to any one of claims 1 to 3. adding resin powder to the microfiber cellulose dispersion prior to dehydration of the microfiber cellulose dispersion;
and no resin is added after dehydration and drying of the microfiber cellulose dispersion.
A method for producing a fibrous cellulose composite resin according to any one of claims 1 to 3. A method of defibrating raw material fibers in a range where the average fiber width is 0.1 μm or more and the fibrillation rate is 30% or less to obtain a dispersion of microfiber cellulose, and drying the dispersion of microfiber cellulose,
Prior to drying the microfiber cellulose dispersion, dehydration is performed until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A method for producing a fibrous cellulose-containing material, characterized by: A fibrous cellulose content obtained by drying a dispersion of microfiber cellulose having an average fiber width of 0.1 μm or more and a fibrillation rate of 30% or less , and a resin,
The fibrous cellulose-containing material is dehydrated prior to drying the microfiber cellulose dispersion until the water content of the microfiber cellulose dispersion is 30% by mass or more and 93% by mass or less.
A fibrous cellulose composite resin characterized by: