JP5798504B2 - Method for producing fine fibrous cellulose, method for producing nonwoven fabric, fine fibrous cellulose, fine fibrous cellulose-containing slurry, nonwoven fabric, and composite - Google Patents

Description

  The present invention relates to a method for producing fine fibrous cellulose, a method for producing a nonwoven fabric, fine fibrous cellulose, a slurry containing fine fibrous cellulose, a nonwoven fabric, and a composite.

  In recent years, materials using reproducible natural fibers have attracted attention due to the substitution of petroleum resources and the growing environmental awareness. Among natural fibers, cellulose fibers having a fiber diameter of 10 to 50 μm, especially wood-derived cellulose fibers (pulp) have been widely used as paper products so far. In addition, fine fibrous cellulose having a fiber diameter of 1 μm or less is also known as the cellulose fiber, and the sheet containing the fine fibrous cellulose has advantages such as high mechanical strength, and can be used for various applications. Application has been studied (Patent Document 1). For example, it is known that fine fibrous cellulose is made into a non-woven fabric and used as a high-strength sheet.

As a method for producing fine fibrous cellulose, Patent Document 2 discloses a method of treating lignocellulose in an aqueous solvent containing a nitroxyl radical derivative, an alkali bromide and an oxidizing agent.
Patent Document 3 discloses a method in which a polybasic acid anhydride is half-esterified into a part of a hydroxy group of cellulose to introduce a carboxy group, and then fibrillated and refined.

JP 2008-24788 A JP 2008-308802 A JP 2009-293167 A

However, Patent Document 2 requires the use of a special catalyst, which increases the cost. In the method for producing fine fibrous cellulose described in Patent Document 3, the fiber raw material is insufficiently refined. Since the yield was low and the dispersion was insufficiently stable, there were problems such as low production efficiency from the fiber raw material, high cost, and high environmental load.
An object of this invention is to provide the manufacturing method of the fine fibrous cellulose which solved the said problem, the manufacturing method of a nonwoven fabric, a fine fibrous cellulose, the fine fibrous cellulose containing slurry, a nonwoven fabric, and a composite_body | complex.

The present invention has the following aspects.
(1) (a) The process which processes the fiber raw material containing a cellulose by the at least 1 sort (s) of compounds chosen from the oxo acid of phosphorus or those salts , heating at 100-170 degreeC , (b) said (a And a step of defibrating the cellulose treated in the step, and a method for producing fine fibrous cellulose.
(2) The method for producing fine fibrous cellulose according to (1), wherein the fiber raw material is a chemical pulp obtained from wood.
(3) The method for producing fine fibrous cellulose according to (1) or (2), wherein the at least one compound selected from the oxo acid of phosphorus or a salt thereof is a compound having a phosphate group.
(4) A dehydration step of dehydrating a slurry containing fine fibrous cellulose produced by the method for producing fine fibrous cellulose according to any one of (1) to (3) on a filter medium to obtain a wet paper; And a drying process for drying the wet paper.

(5) A fine fiber having a fiber width of 1 to 1000 nm and a part of the hydroxy group of cellulose constituting the fiber is substituted with a functional group represented by the following structural formula (1) and a phosphorus oxo acid group is introduced It is fibrous cellulose, Comprising: The amount of introduction | transduction of a phosphorus oxo acid group is 0.1-2.0 mmol per 1g of fine fibrous cellulose, Fine fibrous cellulose characterized by the above-mentioned.
In the structural formula (1), a, b, m, and n are natural numbers (provided that a = b × m). At least one of α ¹ , α ² ,..., α ⁿ and α ′ is O ⁻ , and the rest is either R or OR. R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group, respectively. One of a hydrogen group, an aromatic group, and a derivative group thereof. β is a monovalent or higher cation composed of an organic substance or an inorganic substance.

(6) A fine fibrous cellulose-containing slurry obtained by dispersing the fine fibrous cellulose according to (5) in a dispersion medium.
(7) A nonwoven fabric containing the fine fibrous cellulose according to (5).
(8) A composite containing the fine fibrous cellulose according to (5) and a matrix material (9) A composite containing the nonwoven fabric according to (7) and a matrix material.

According to the method for producing fine fibrous cellulose of the present invention, since the fiber raw material can be sufficiently refined and the yield of fine fibrous cellulose is high, the production efficiency of fine fibrous cellulose from the fiber raw material is high. Moreover, the manufacturing method of the fine fibrous cellulose of this invention is low cost, and its environmental impact is small.
According to the method for producing a nonwoven fabric of the present invention, the production efficiency of the nonwoven fabric with respect to the fiber raw material can be improved.
Since the fine fibrous cellulose of the present invention has a small fiber width and a large axial ratio (fiber length / fiber width), the slurry stability of the fine fibrous cellulose is high, and the obtained nonwoven fabric has high strength. The composite of the fine fibrous cellulose and the matrix resin of the present invention has high strength and a low linear thermal expansion coefficient.

2 is a transmission electron micrograph of cellulose contained in the defibrated pulp slurry obtained in Example 1. FIG. 4 is a transmission electron micrograph of cellulose contained in the defibrated pulp slurry obtained in Example 3. FIG. It is a schematic block diagram of one Embodiment of the manufacturing apparatus used with the manufacturing method of the nonwoven fabric of this invention.

<Fine fibrous cellulose>
In the fine fibrous cellulose of the present invention, a part of the hydroxy group (—OH group) is substituted with a functional group represented by the following structural formula (1). Moreover, it is a cellulose fiber or rod-like particle | grain far thinner than the pulp fiber normally used for a papermaking use.

In the structural formula (1), a, b, m, and n are natural numbers (provided that a = b × m).
At least one of α ¹ , α ² ,..., α ⁿ and α ′ is O ⁻ , and the rest is either R or OR. All of α ⁿ and α ′ may be O ⁻ . When n is 2 or more and α ′ is R or OR, at least one of each α ⁿ is O ⁻ and the rest is R or OR. When n is 2 or more and α ′ is O ⁻ , each α ⁿ may be all R or all OR, and at least one is O ⁻ and the rest is R or It may be OR.
R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group, respectively. A hydrogen group, an aromatic group, and derivatives thereof.
Examples of the saturated-linear hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Examples of the saturated-branched hydrocarbon group include i-propyl group and t-butyl group. Examples of the saturated-cyclic hydrocarbon group include a cyclopentane group and a cyclohexane group. Examples of the unsaturated-linear hydrocarbon group include a vinyl group and an allyl group. Examples of the unsaturated-branched hydrocarbon group include i-propenyl group and 3-butenyl group. Examples of the saturated-cyclic hydrocarbon group aromatic group include a phenyl group and a naphthalene group.
The derivative in R is a functional group in which at least one of functional groups such as a carboxy group, a hydroxy group, and an amino group is added to or substituted for the main chain or side chain of the various hydrocarbon groups Is mentioned.
The number of carbon atoms constituting the main chain of R is preferably 20 or less, and more preferably 10 or less. When the number of carbon atoms constituting the main chain of R exceeds 20, the molecule of the Roxo group containing R becomes too large, and it is difficult to penetrate into the fiber raw material, which may reduce the yield of fine fibrous cellulose. is there.
β is a monovalent or higher cation composed of an organic substance or an inorganic substance. Examples of the monovalent or higher cation made of an organic substance include aliphatic ammonium and aromatic ammonium. Examples of the monovalent or higher cation made of an inorganic substance include ions of alkali metals such as sodium, potassium and lithium, calcium, Examples include divalent metal cations such as magnesium, hydrogen ions, and the like. These can be applied alone or in combination of two or more. As the monovalent or higher cation composed of an organic substance or an inorganic substance, sodium and potassium ions that are less likely to yellow when heated to a fiber raw material containing β and are industrially useful are preferable.

  The structural formula (1) is preferably a monoester that does not contain a cellulose molecular chain at α and α ′. In the case where α and α ′ contain cellulose molecular chains, the cellulose molecular chains are cross-linked with each other, so that there is a possibility of inhibiting the miniaturization.

The fiber width of the fine fibrous cellulose of the present invention is preferably 1 nm to 1000 nm, more preferably 2 nm to 500 nm, still more preferably 4 nm to 100 nm as observed with an electron microscope. When the fiber width of the fine fibrous cellulose is less than 1 nm, the physical properties (strength, rigidity, dimensional stability) as the fine fibrous cellulose are not expressed because the cellulose molecules are dissolved in water. On the other hand, when it exceeds 1000 nm, it cannot be said that it is a fine fibrous cellulose, but is only a fiber contained in a normal pulp, and physical properties (strength, rigidity, dimensional stability) as a fine fibrous cellulose cannot be obtained.
In applications where transparency is required for fine fibrous cellulose, when the fiber width exceeds 30 nm, it approaches 1/10 of the wavelength of visible light, and when combined with a matrix material, visible light is refracted and scattered at the interface. The fiber width is preferably 2 nm to 30 nm, more preferably 2 to 20 nm, because it tends to occur and the transparency tends to decrease. The composite obtained from the fine fibrous cellulose as described above generally has a high strength because it becomes a dense structure, and in addition to obtaining a high elastic modulus derived from cellulose crystals, it also scatters visible light. Since there are few, high transparency is also obtained.

Here, the fine fibrous cellulose has a type I crystal structure. In a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418４) monochromatized with graphite, 2θ = It can be identified by having typical peaks at two positions near 14-17 ° and 2θ = 22-23 °.
Moreover, the measurement of the fiber width by electron microscope observation of fine fibrous cellulose is performed as follows. A slurry containing fine fibrous cellulose having a concentration of 0.05 to 0.1% by mass is prepared, and the slurry is cast on a carbon film-coated grid subjected to a hydrophilization treatment to obtain a sample for TEM observation. When wide fibers are included, an SEM image of the surface cast on glass may be observed. Observation by an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times, 20000 times, 40000 times, or 50000 times depending on the width of the constituent fibers. However, the sample, observation conditions, and magnification are adjusted to satisfy the following conditions.
(1) One straight line X is drawn at an arbitrary location in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y perpendicular to the straight line is drawn in the same image, and 20 or more fibers intersect the straight line Y.
The width of the fiber that intersects with the straight line X and the straight line Y is visually read from the observation image that satisfies the above conditions. In this way, at least three sets of images of the surface portion that do not overlap each other are observed, and the width of the fiber intersecting with the straight line X and the straight line Y is read for each image. Thus, at least 20 × 2 × 3 = 120 fiber widths are read. The fine fiber width in the present invention is an average value of the fiber widths thus read.

  The fiber length of the fine fibrous cellulose of the present invention is preferably 0.1 μm or more. When the fiber length is less than 0.1 μm, it is difficult to obtain the strength improvement effect when the fine fibrous cellulose is combined with the resin. The fiber length can be obtained by image analysis of TEM, SEM, or AFM. The said fiber length is a fiber length which occupies 30 mass% or more of a fine fiber.

  The axial ratio (fiber length / fiber width) of the fine fibrous cellulose according to the present invention is preferably in the range of 100 to 10,000. If the axial ratio is less than 100, it may be difficult to form a fine fibrous cellulose-containing nonwoven fabric. When the axial ratio exceeds 10,000, the slurry viscosity becomes high, which is not preferable.

  The ratio of the crystal part contained in the fine fibrous cellulose of the present invention is a cellulose fiber having a crystallinity obtained by X-ray diffraction of 60% or more, and the crystallinity is preferably 65% or more. When it is preferably 70% or more, further excellent performance can be expected in terms of heat resistance and low linear thermal expansion. The degree of crystallinity was determined by measuring the X-ray diffraction profile and determining the crystallinity by a conventional method (Seagal et al., Textile Research Journal, 29, 786, 1959).

By replacing a part of the hydroxy group of cellulose of the fiber raw material with the functional group of the above structural formula (1), oxoacid having a hydroxy group and an oxo group bonded to a phosphorus atom (hereinafter referred to as “phosphonooxoacid”) Is introduced). It is presumed that the electrical repulsion between the cellulose fibers is strengthened by the phosphorus oxoacid. Moreover, it is excellent in the dispersion stability at the time of making a slurry.
The introduction amount of the phosphorus oxo acid group in the hydroxy group (-OH group) of the cellulose of the fiber raw material is preferably 0.1 to 2.0 mmol, more preferably 0.2 to 1.5 mmol per 1 g (mass) of fine fibrous cellulose. . If the introduction amount of the phosphorus oxo acid group is less than 0.1 mmol, it is difficult to refine the fiber raw material, and the stability of the fine fibrous cellulose is poor. If the introduction amount of the phosphorus oxo acid group exceeds 2.0 mmol, the fine fibrous cellulose may be dissolved.

Here, the amount of the phosphorus oxo acid group introduced into the cellulose was calculated by applying TAPPI T237 cm-08 (2008). Specifically, in order to make it possible to calculate the introduction amount of acidic groups introduced into cellulose over a wider range, among the test solutions used in the test method, sodium bicarbonate (NaHCO ₃ ) / sodium chloride (NaCl) = The test solution in which 0.84 g / 5.85 g was dissolved and diluted in 1000 ml with distilled water was changed to a test solution in which 1.60 g of sodium hydroxide was dissolved and diluted in 1000 ml with distilled water. The calculation is performed according to TAPPI T237 cm-08 (2008) except that the difference between the calculated values is a substantial substituent introduction amount.
In addition, since the calculation method for introducing an acidic group is basically a method for calculating the introduction amount of a monovalent acidic group (carboxy group), the calculation of the introduction amount of a phosphorus oxo acid group which is a polyvalent acidic group is performed. The value obtained by dividing the introduction amount of the substituent obtained as the introduction amount of the monovalent acidic group by the acid number of the phosphorus oxo acid group was defined as the introduction amount of the phosphorus oxo acid group.

<Manufacture of fine fibrous cellulose>
In the method for producing fine fibrous cellulose of the present invention, a fiber raw material containing cellulose is treated with at least one compound selected from oxo acid of phosphorus or a salt thereof (hereinafter referred to as “compound A”), and then cellulose. A phosphorus oxoacid group introduction step (a) for introducing a phosphorus oxoacid group into the cellulose, and after completion of the step (a), a cellulose into which a phosphorus oxoacid group has been introduced (hereinafter referred to as “phosphorous acid group-introduced cellulose”) is defibrated. A defibrating treatment step (b).
Hereinafter, these two steps will be described in detail.

[Phosphooxo group introduction step (a)]
Examples of the method of treating the fiber raw material with the compound A include a method of mixing a powder or aqueous solution of the compound A with a dry or wet fiber raw material, a method of adding the powder or aqueous solution of the compound A to the fiber raw material slurry, and the like. Can be mentioned. Among these, since the uniformity of the reaction is high, a method of adding an aqueous solution of Compound A to a dry fiber raw material (pulp) or a powder or aqueous solution of Compound A to a wet fiber raw material (pulp) The method is preferred.

Examples of the fiber raw material containing cellulose include paper pulp, cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, cellulose isolated from sea squirts and seaweeds, and the like. Among these, paper pulp is preferable in terms of availability. Paper pulp includes hardwood kraft pulp (bleached kraft pulp (LBKP), unbleached kraft pulp (LUKP), oxygen bleached kraft pulp (LOKP), etc.), softwood kraft pulp (bleached kraft pulp (NBKP), unbleached kraft pulp) (NUKKP, oxygen bleached kraft pulp (NOKP), etc.), sulfite pulp (SP), chemical pulp such as soda pulp (AP), semi-chemical pulp (SCP), semi-chemical pulp such as chemiground wood pulp (CGP) In addition, mechanical pulp such as groundwood pulp (GP) and thermomechanical pulp (TMP, BCTMP), non-wood pulp using raw material such as cocoon, sardine, hemp, kenaf and the like, and deinked pulp using raw paper as a raw material. A fiber raw material may be used individually by 1 type, and may be used in mixture of 2 or more types.
Among the fiber raw materials, wood pulp and deinked pulp are preferable in terms of easy availability. Furthermore, among wood pulps, chemical pulp has a high cellulose ratio, so the yield of fine fibrous cellulose is high, and the cellulose in pulp is small and long fiber fine fibrous cellulose with a large axial ratio is obtained. Are particularly preferable. Among chemical pulps, kraft pulp and sulfite pulp are most preferably selected.

  Pulp for papermaking may be beaten with a double disc refiner, a single disc refiner, a beater, etc., but pulp that is not sufficiently beaten (Canadian Standard Freeness (CSF) is preferably 400 ml or more, more preferably 500 ml or more. Pulp). When a pulp that is not so much beaten is used, the entanglement between the fine fibrous celluloses obtained in the defibrating process described later can be reduced, and the stability of the fine fibrous cellulose is improved. Moreover, the dehydration detergency at the time of wash | cleaning a pulp with water or an organic solvent before and behind the alkali treatment mentioned later improves.

Examples of the compound A used in the present invention include phosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, polyphosphonic acid, and salts or esters thereof.
Among these, a compound having a phosphoric acid group is preferable because it is low-cost, easy to handle, and can further improve the fibrillation efficiency by introducing a phosphoric acid group into the hydroxy group of cellulose.
Examples of the compound having a phosphoric acid group include phosphoric acid, lithium dihydrogen phosphate which is a lithium salt of phosphoric acid, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, lithium polyphosphate, and sodium salt of phosphoric acid. Sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium polyphosphate, and the potassium salt of phosphoric acid, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, triphosphate Examples include potassium, potassium pyrophosphate, and potassium polyphosphate.
Among these, phosphoric acid, sodium salt of phosphoric acid, from the viewpoint of high efficiency of introducing phosphate groups, easy improvement of the defibrating efficiency in the following defibrating process, low cost, and industrial applicability A potassium salt of phosphoric acid is preferable, and sodium dihydrogen phosphate and disodium hydrogen phosphate are more preferable.
Further, the compound A is preferably used as an aqueous solution because the uniformity of the reaction is increased and the efficiency of introduction of the phosphorus oxo acid group is increased. The pH of the aqueous solution of Compound A is preferably 7 or less because the efficiency of introduction of the phosphorus oxoacid group is high, but is preferably 3 to 7 from the viewpoint of suppressing hydrolysis of pulp fibers.

  The mass ratio of the compound A to the fiber raw material is preferably 0.2 to 500 parts by mass, more preferably 1 to 400 parts by mass, and 2 to 200 parts by mass with respect to 100 parts by mass of the fiber raw material. Is most preferred. If the ratio of the compound A is more than the said lower limit, the yield of fine fibrous cellulose can be improved more. However, even if the upper limit is exceeded, the effect of improving the yield reaches its peak and only the compound A is used in vain.

In the step (a), heat treatment is preferably performed. It is preferable that the heat processing temperature is 250 degrees C or less from the point of the thermal decomposition temperature of a cellulose. Moreover, it is preferable that the heat processing temperature is 100-170 degreeC from a viewpoint of suppressing hydrolysis of a cellulose. Furthermore, for heating while the fiber raw material slurry to which Compound A is added during the heat treatment contains water, it is preferably 130 ° C. or lower, more preferably 110 ° C. or lower to sufficiently remove the water in the slurry. After removing and drying, heat treatment is preferably performed at 100 to 170 ° C. Moreover, you may use a vacuum dryer when removing the water | moisture content in a slurry.
In addition, during the heat treatment, while the fiber raw material slurry to which compound A is added contains water, if the time for which the fiber raw material is allowed to stand becomes longer, the compound A dissolved with water molecules is dried and the fiber raw material surface Move to. For this reason, the concentration of the compound A in the fiber raw material may be uneven, and the introduction of the phosphorus oxo acid group to the cellulose surface may not proceed uniformly. In order to suppress the occurrence of unevenness in the concentration of compound A in the fiber material (pulp) due to drying, a very thin sheet-like fiber material (pulp) is used, or heat drying while kneading the fiber material and compound A with a kneader or the like. / A method of drying under reduced pressure may be employed.
As a heating apparatus used for the heat treatment, the water retained by the slurry and the water generated by the addition reaction to the cellulose hydroxyl group such as a phosphorus oxo acid group can always be discharged out of the apparatus system. A blow type oven or the like is preferable. If water in the apparatus system is always discharged, in addition to suppressing the hydrolysis reaction of the phosphorus oxo acid ester bond, which is the reverse reaction of the phosphorus oxo acid esterification, the acid hydrolysis of the cellulose sugar chain can also be suppressed. A fine fibrous cellulose having a high ratio can be obtained.

[Defibration processing step (b)]
In the defibrating treatment step (b), a cellulose fiber containing slurry is usually obtained by defibrating the phosphorus oxoacid-introduced cellulose using a defibrating device.
Defibration treatment equipment includes high-speed defibrator, grinder (stone mortar grinder), high-pressure homogenizer and ultra-high pressure homogenizer, high-pressure collision grinder, ball mill, bead mill, disk refiner, conical refiner, twin-screw kneader, vibration mill A wet milling device such as a homomixer under high-speed rotation, an ultrasonic disperser, or a beater can be used as appropriate.

  In the defibrating treatment, it is preferable to dilute the phosphorus oxoacid-introduced cellulose in water or an organic solvent alone or in combination to form a slurry. The diluted solid content concentration of the phosphorooxy acid-introduced cellulose is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass. If the solid content concentration of the diluted phosphorus oxoacid-introduced cellulose is not less than the lower limit, the efficiency of the defibrating treatment is improved, and if it is not more than the upper limit, blockage in the defibrating apparatus can be prevented.

[Other processing steps]
In the present invention, it is preferable to have an alkali treatment step between step (a) and step (b) because the yield of fine fibrous cellulose is improved. In addition, by the alkali treatment, a cation can be supplied to the phosphorus oxo acid group introduced into the cellulose to easily form a salt.

The method for the alkali treatment is not particularly limited, and examples thereof include a method of immersing the phosphorooxy acid group-introduced cellulose in an alkali solution.
The alkali compound contained in the alkali solution may be an inorganic alkali compound or an organic alkali compound. Examples of inorganic alkali compounds include alkali metal hydroxides or alkaline earth metal hydroxides, alkali metal carbonates or alkaline earth metal carbonates, alkali metal phosphates or alkaline earth metal phosphoric acids. Salt. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide, and examples of the alkaline earth metal hydroxide include calcium hydroxide.
Examples of the alkali metal carbonate include lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, and sodium hydrogen carbonate. Examples of the alkaline earth metal carbonate include calcium carbonate.
Examples of the alkali metal phosphate 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 the organic alkali compounds include ammonia, aliphatic amines, aromatic amines, aliphatic ammoniums, aromatic ammoniums, heterocyclic compounds and their hydroxides, carbonates, and phosphates.
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, etc. Can be mentioned.

The solvent in the alkaline solution may be either water or an organic solvent, but is preferably a polar solvent (polar organic solvent such as water or alcohol), and more preferably an aqueous solvent containing at least water.
Of the alkaline solutions, sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are particularly preferred because of their high versatility.

  The pH at 25 ° C. of the alkaline solution in which the phosphorus oxo acid group-introduced cellulose is immersed is preferably 9 or more, more preferably 10 or more, and even more preferably 11-14. If the pH of the alkaline solution is at least the lower limit, the yield of fine fibrous cellulose will be higher. However, when pH exceeds 14, the handleability of an alkaline solution will fall.

  In order to reduce the amount of the alkali solution used in the alkali treatment step, the phosphorus oxo acid group-introduced cellulose may be washed with water or an organic solvent before the alkali treatment step. After the alkali treatment, in order to improve the handleability, it is preferable to wash the alkali-treated phosphooxo acid group-introduced cellulose with water or an organic solvent before the defibrating treatment step.

<Effect>
According to the manufacturing method of the said fine fibrous cellulose, a fiber raw material (pulp) can fully be refined | miniaturized, the yield of a fine fibrous cellulose becomes high, and the manufacturing efficiency of a fine fibrous cellulose improves. The reason for this is that the pulp treated with Compound A is introduced with phosphorooxy acid groups in cellulose, the electrostatic repulsion between the cellulose fibers is increased, the osmotic pressure of water between the cellulose is improved, and the fibrillation property is improved. Is estimated to be high.
Moreover, since the manufacturing method of the said fine fibrous cellulose does not need to use a nitroxy radical derivative, an alkali bromide, and an oxidizing agent, cost is low and an environmental load is also small.

<Slurry containing fine fibrous cellulose>
The fine fibrous cellulose-containing slurry of the present invention is obtained by dispersing fine fibrous cellulose in a dispersion medium.
As the dispersion medium, a polar organic solvent can be used in addition to water. Preferred polar organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and tbutyl alcohol, acetone. And ketones such as methyl ethyl ketone (MEK), ethers such as diethyl ether and tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc) and the like. These may be one type or two or more types. Further, a nonpolar organic solvent may be used in addition to the water and the polar organic solvent as long as the dispersion stability of the fine fibrous cellulose-containing slurry is not hindered. The content of fine fibrous cellulose in the fine fibrous cellulose-containing slurry is preferably 0.05 to 20% by mass, and more preferably 0.1 to 10% by mass. If the content of the fine fibrous cellulose is not less than the lower limit, the production efficiency in producing a non-woven fabric and a composite described later is excellent, and if it is not more than the upper limit, the dispersion stability of the slurry is excellent.

<Nonwoven fabric>
Below, one embodiment of the nonwoven fabric of the present invention and its manufacturing method is described.
The nonwoven fabric of the present invention contains the fine fibrous cellulose.

  The thickness of the nonwoven fabric of the present invention is not particularly limited, but is preferably 10 μm or more, more preferably 50 μm or more, particularly preferably 80 μm or more, preferably 10 cm or less, more preferably 1 cm or less, more preferably 1 mm. Hereinafter, it is particularly preferably 250 μm or less. The thickness of the nonwoven fabric is preferably thicker than the above lower limit from the viewpoint of production stability and strength, and is preferably thinner than the upper limit from the viewpoint of productivity, uniformity and resin impregnation.

  The nonwoven fabric of the present invention preferably has a porosity of 20 vol% or more, and more preferably 35 vol% or more and 60 vol% or less. When the porosity of the nonwoven fabric is small, the reaction is difficult to proceed when the above chemical modification is applied, or the matrix material such as resin is difficult to impregnate, and the unimpregnated portion remains when the composite is formed. Scattering occurs and haze increases. Moreover, when the non-woven fabric has a high porosity, when it is made into a composite, a sufficient reinforcing effect by cellulose fibers cannot be obtained, and the linear thermal expansion coefficient becomes large, which is not preferable.

The porosity here refers to the volume ratio of voids in the nonwoven fabric, and the porosity can be determined from the area, thickness, and mass of the nonwoven fabric according to the following formula.
Porosity (vol%) = {(1-B / (M × A × t)} × 100
Here, A is the area (cm ² ) of the nonwoven fabric, t (cm) is the thickness, B is the mass (g) of the nonwoven fabric, M is the density of cellulose, and M = 1.5 g / cm ³ is assumed in the present invention. To do. The film thickness of the nonwoven fabric is measured at 10 points with respect to various positions of the nonwoven fabric using a film thickness meter (PDN-20 manufactured by PEACOK), and the average value is adopted.

  Moreover, when calculating | requiring the porosity of the nonwoven fabric in a composite_body | complex, a porosity can also be calculated | required by carrying out image analysis of the spectral analysis and SEM observation of the cross section of a composite_body | complex.

The air permeability of the nonwoven fabric of the present invention is not particularly limited because it depends on the basis weight. For example, in the case of a sheet having a basis weight of 50 g / m ² , it is preferably 100 to 20000 seconds / 100 cc.

(manufacturing device)
In FIG. 5, the manufacturing apparatus used with the manufacturing method of the nonwoven fabric of this embodiment is shown. The manufacturing apparatus 1 of this embodiment includes a dewatering section 20, a drying section 40 provided on the downstream side of the dewatering section 20, and a winding section 60 provided on the downstream side of the drying section.

[Dehydration section]
The dewatering section 20 is a section for dewatering the fine fibrous cellulose-containing slurry 3a using the papermaking wire 10 to obtain the water-containing web 3b.
As the papermaking wire, woven fabrics such as plastic wires and metal wires, nonwoven fabrics, and papers can be used. Among these, nonwoven fabrics and papers are preferable.

The dewatering section 20 is provided with a delivery reel 21 for feeding out the papermaking wire 10, a discharge unit 20a for the fine fibrous cellulose-containing slurry 3a, and a dehydrating unit 30 for the dispersion medium.
A plurality of die heads 22 for discharging the fine fibrous cellulose-containing slurry 3a to the running paper-making wire 10 fed from the delivery reel 21 and disposed downstream of each die head 22 are discharged to the discharge unit 20a. A plate 24 for leveling the upper surface of the fine fibrous cellulose-containing slurry 3a is provided.
The discharge unit 20a and the dehydrating unit 30 are provided with suction devices 26 and 32 for forcibly dehydrating the dispersion medium from the fine fibrous cellulose-containing slurry 3a. The suction devices 26 and 32 are disposed below the paper making wire 10, and a plurality of suction holes (not shown) connected to a vacuum pump (not shown) are formed on the upper surface thereof. However, it is preferable that the suction hole is not formed on the upstream side of the suction device 26 and is a non-suction hole that is not connected to the vacuum pump. If the suction hole is formed on the upstream side, the surface of the coating film of the fine fibrous cellulose-containing slurry 3a may become rough. Further, since the amount of dewatering is reduced on the downstream side, the suction device 32 in the dewatering unit 30 may not have a hole formed on the downstream side.

[Drying section]
The drying section 40 is a section that obtains the nonwoven fabric 3c by drying the hydrous web 3b using a dryer. The drying section 40 is provided in a hood 49 with a first dryer 42 and a second dryer 52 configured by cylinder dryers, and a felt cloth 44 disposed along the outer periphery of the first dryer 42. The first dryer 42 is disposed on the upstream side of the second dryer 52. Further, the felt cloth 44 is endless and is circulated by a guide roll 46.
In the drying section 40, the water-containing web 3 b is transferred by the guide roll 48. Specifically, first, the surface A (hereinafter referred to as “application surface A”) of the water-containing web 3b on which the fine fibrous cellulose-containing slurry 3a is applied is in contact with the outer peripheral surface of the first dryer 42, and the water-containing web 3b. The surface B on which the fine fibrous cellulose-containing slurry 3 a has not been applied (hereinafter referred to as “non-application surface B”) is transferred so as to be in contact with the felt cloth 44, and then the application surface A is the outer peripheral surface of the second dryer 52. To come in contact with.

[Winding section]
The winding section 60 is a section that separates the nonwoven fabric 3c from the papermaking wire 10 and winds it. In the winding section 60, a pair of separation rollers 62a and 62b for separating the nonwoven fabric 3c from the papermaking wire 10, a winding reel 64 for winding the nonwoven fabric 3c, and a used papermaking wire 10 are wound and collected. A collection reel 66 is provided. The separation roller 62b is disposed on the papermaking wire 10 side, and the separation roller 62a is disposed on the nonwoven fabric 3c side.

(Production method)
The nonwoven fabric manufacturing method of the present embodiment includes a dehydration step of dehydrating a slurry containing fine fibrous cellulose produced by the above-described fine fibrous cellulose production method on a filter medium to obtain wet paper, and drying the wet paper It has a drying process for obtaining a nonwoven fabric and a winding process for winding the nonwoven fabric.

[Dehydration process]
In the dehydration step, the papermaking wire 10 is unwound from the delivery reel 21, the fine fibrous cellulose-containing slurry 3a is discharged from the die head 22 to the papermaking wire 10, and the upper surface of the fine fibrous cellulose-containing slurry 3a of the papermaking wire 10 is plated. Level by 24. At the same time, the dispersion medium contained in the fine fibrous cellulose-containing slurry 3a on the papermaking wire 10 is sucked and dehydrated by the suction devices 26 and 32 to obtain the water-containing web 3b.
In the dehydration process, when the running tension of the papermaking wire 10 is large, the papermaking wire 10 may be broken. Therefore, the wire used for normal papermaking is placed under the papermaking wire 10 for papermaking. The wire 10 may be supported.

Before supplying the fine fibrous cellulose-containing slurry 3a to the papermaking wire 10, the papermaking wire 10 may be previously impregnated with water to be in a wet state. When the fine fibrous cellulose-containing slurry 3a is discharged to the papermaking wire 10, the wrinkles may be generated due to water absorption of the wire. However, if it is made wet in advance, the generation of the wrinkles can be prevented.
Examples of means for bringing the papermaking wire 10 into a wet state include a water tank in which the papermaking wire 10 is immersed in water and a water coating apparatus. As the water coating apparatus, a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a curtain coater, a die coater, or the like can be used.

The fine fibrous cellulose-containing slurry 3a supplied to the papermaking wire 10 in the dehydration step is a liquid containing fine fibrous cellulose and water.
Moreover, the fine fibrous cellulose-containing slurry 3a may contain a resin emulsion. Here, the resin emulsion is an emulsion in which particles of natural resin or synthetic resin having a particle diameter of 0.001 to 10 μm are emulsified in water. The particulate resin contained in the resin emulsion is not particularly limited, but polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, poly (meth) acrylic acid alkyl ester polymer, ( Meth) acrylic acid alkyl ester copolymer, poly (meth) acrylonitrile, polyester, polyurethane, polyamide, epoxy resin, oxetane resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, silicon resin, diallyl phthalate resin, etc. precursor, and a resin emulsion of such monomer or oligomer constituting these, natural rubber, styrene - butadiene copolymer, the molecular chain terminal _{-SH, -CSSH, -SO 3 H,} - (COO) x M, - ( SO ₃₎ x M and -CO-R ( In the functional group, styrene modified with at least one functional group selected from the group consisting of M is a cation, x is an integer of 1 to 3 depending on the valence of M, and R is an alkyl group. -Modified styrene-butadiene copolymer such as butadiene copolymer, acid-modified, amine-modified, amide-modified, acrylic-modified, (meth) acrylonitrile-butadiene copolymer, polyisoprene, polychloroprene, styrene-butadiene-methyl methacrylate Examples thereof include a polymer and a styrene- (meth) acrylic acid alkyl ester copolymer. Further, polyethylene, polypropylene, polyurethane, ethylene-vinyl acetate copolymer or the like may be emulsified by a post-emulsification method. Two or more kinds of these resin emulsions may be contained.
In addition, when the slurry is dehydrated and dried, it is obtained in a state in which fine fiber cellulose and a matrix material are contained in the nonwoven fabric 3c. You can also. In this case, a plurality of sheets may be laminated and subjected to a curing process.

Furthermore, the fine fibrous cellulose-containing slurry 3a may contain a cellulose coagulant. Examples of the cellulose coagulant include water-soluble inorganic salts and water-soluble organic compounds containing a cationic functional group.
Water-soluble inorganic salts include sodium chloride, calcium chloride, potassium chloride, ammonium chloride, magnesium chloride, aluminum chloride, sodium sulfate, potassium sulfate, aluminum sulfate, magnesium sulfate, sodium nitrate, calcium nitrate, sodium carbonate, potassium carbonate, ammonium carbonate Examples thereof include sodium phosphate and ammonium phosphate.
Examples of the water-soluble organic compound containing a cationic functional group include polyacrylamide, polyvinylamine, urea resin, melamine resin, melamine-formaldehyde resin, and a polymer obtained by polymerizing or copolymerizing a monomer containing a quaternary ammonium salt.

Furthermore, the fine fibrous cellulose-containing slurry 3a may contain one or more materials such as a water-soluble organic polymer, an inorganic polymer, and a hybrid polymer of an organic polymer and an inorganic polymer.
Here, as the water-soluble polymer, polyvinyl alcohol, vinyl alcohol / ethylene copolymer, those having a copolymer structure of vinyl alcohol and other monomers such as butyral, polyethylene oxide or those having its terminal modified with alkyl , Polypropylene oxide, nonionic water-soluble polymers such as polybutyral resin (water-soluble grade), poly (meth) acrylic acid and poly (meth) acrylate, and organic amino derivatives of poly (meth) acrylic acid Examples thereof include esters, polyethyleneimine and derivatives thereof, polyamines, polyacrylamides, acrylamide / sodium acrylate copolymers, starches, cationized starches, phosphorylated starches, carboxymethylcelluloses, alginic acids, and alginates.
Examples of the inorganic polymer include ceramics such as glass, silicate material, and titanate material, and these can be formed by, for example, dehydration condensation reaction of alcoholate.

Furthermore, in order to improve the porosity of the resulting nonwoven fabric 3c, it is preferable to contain an organic solvent in the fine fibrous cellulose-containing slurry 3a, or to replace the moisture of the wet paper after dehydration with an organic solvent. When mixing the organic solvent, the mass ratio of water to the organic solvent (water: organic solvent) is preferably 100: 10 to 10: 100, more preferably 100: 30 to 30: 100, : 50 to 50: 100 is more preferable. If the mixing amount of the organic solvent is not less than the lower limit, the porosity of the nonwoven fabric 3c can be sufficiently improved, and if it is not more than the upper limit, the increase in viscosity of the fine fibrous cellulose-containing slurry 3a can be suppressed. .
When the water content of the wet paper after the dehydration is replaced with an organic solvent, after the fine fibrous cellulose-containing slurry 3a is dehydrated, the wet paper prepared to have a solid content of 5% by mass to 30% by mass is combined with an organic solvent or water. The nonwoven fabric of the present invention can be obtained by impregnating a mixed solution of an organic solvent or applying the mixed solution, treating the mixture by suction dehydration, and drying.

Examples of the organic solvent include alcohols, ketones, ethers, esters, aromatic compounds, hydrocarbons, cyclic hydrocarbons, and cyclic hydrocarbon derivatives.
Examples of alcohol include methanol, ethanol, propanol, isopropanol, n-butanol, t-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol, benzyl alcohol, phenol and the like Monohydric alcohols, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, triethylene Dihydric alcohols such as glycol, 1,2-hexanediol, 1,2-octanediol, dipropylene glycol methyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol monoe Glycol ethers such as ether, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, polyethylene glycol, polypropylene glycol and glycerin.
Ethers include diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol isopropyl methyl ether and other glymes, 1,4-dioxane, tetrahydrofuran And anisole.
Examples of the ketone include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, t-butyl methyl ketone, diisopropyl ketone, butyl isopropyl ketone, isobutyl isopropyl ketone, diisobutyl ketone, 3-methyl-2-pentanone, 4-methyl-2- Examples include pentanone, 3-methyl-2-hexanone, 5-methyl-3-heptanone, 2-decanone, 3-decanone, 4-decanone, and 5-decanone.
Esters include methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, butyl acetoacetate, amyl acetate, amyl acetoacetate, hexyl acetate, hexyl acetoacetate, heptyl acetate, aceto Heptyl acetate, octyl acetate, octyl acetoacetate, methyl propionate, ethyl propionate, ethyl 2-hydroxypropionate, methyl butyrate, ethyl butyrate, methyl valerate, ethyl valerate, methyl hexanoate, ethyl hexanoate, methyl heptanoate , Ethyl heptanoate, methyl octanoate, ethyl octanoate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, oxalic acid Dimethyl, oxalic acid Ethyl, dimethyl malonate, diethyl malonate, dimethyl succinate, diethyl succinate, dimethyl maleate, fatty acid esters such as diethyl maleate, methyl benzoate, and aromatic esters such as ethyl benzoate.
Aromatic compounds include benzene, toluene, xylene, ethylbenzene and the like.
Examples of the hydrocarbon include n-hexane, n-heptane, and n-octane.
Examples of the cyclic hydrocarbon include cyclopentane, cyclohexane, and terpene.
Examples of the cyclic hydrocarbon derivative include cyclopentanol, cyclopentanone, cyclopentyl methyl ether, cyclohexanol, cyclohexanone, cyclohexanone dimethyl acetal, terpinolene, terpineol and the like.

  Two or more organic solvents may be mixed and used in combination. Moreover, when mixing and using it, the ratio of the organic solvent which occupies in a mixed solution becomes like this. Preferably it is 40 mass% or more, More preferably, it is 60 mass% or more, More preferably, it is 70 mass% or more. The upper limit of the ratio of the organic solvent is not particularly limited. Two or more organic solvents in the mixed solution may be used. Further, the organic solvent is preferably dissolved in water, but an organic solvent that does not dissolve in water may be emulsified and used as an emulsion.

  The solid content concentration of the fine fibrous cellulose-containing slurry 3a is preferably 0.05 to 1.5% by mass, and more preferably 0.1 to 0.8% by mass. If the concentration of the fine fibrous cellulose-containing slurry 3a is equal to or higher than the lower limit value, sufficient production efficiency can be secured in the dehydration step, and if it is equal to or lower than the upper limit value, increase in viscosity is prevented and handling properties are improved. Can do.

  In the dehydration step, the fine fibrous cellulose-containing slurry 3a is supplied so that the basis weight of the obtained nonwoven fabric 3c is preferably 10 to 900 g / m 2, more preferably 20 to 300 g / m 2. When the basis weight is equal to or higher than the lower limit, the obtained nonwoven fabric 3c can be easily peeled from the papermaking wire 10 and is suitable for continuous production. On the other hand, when the basis weight is not more than the above upper limit value, the dehydration time can be further shortened, and the productivity can be further increased.

[Drying process]
In the drying step, first, the coated surface A is in contact with the outer peripheral surface of the first dryer 42, with the water-containing web 3b placed on the upper surface of the papermaking wire 10 being about half the outer periphery of the heated first dryer 42. It winds and the dispersion medium which remained in the water-containing web 3b is evaporated. The evaporated dispersion medium evaporates from the felt cloth 44 through the pores of the papermaking wire 10.
Next, the water-containing web 3b is wound around about 3/4 of the outer peripheral surface of the heated second dryer 52 so that the coating surface A is in contact with the outer peripheral surface of the second dryer 52, and remains on the water-containing web 3b. Evaporate the dispersion medium.
In this way, the water-containing web 3b is dried to obtain the nonwoven fabric 3c.

[Winding process]
In the winding process, the papermaking wire 10 and the nonwoven fabric 3c are sandwiched between a pair of separation rollers 62a and 62b, whereby the nonwoven fabric 3c is separated from the papermaking wire 10 and transferred to the surface of one separation roller 62a. Then, the nonwoven fabric 3 c is pulled away from the surface of the separation roller 62 a and taken up by the take-up reel 64. At the same time, the used paper making wire 10 is taken up by the collection reel 66.

(Other embodiments)
In the manufacturing method of the nonwoven fabric of this invention, the said manufacturing apparatus 1 does not need to be used. For example, the papermaking wire 10 may be transported on an endless or endless belt.
Moreover, in the manufacturing method of the nonwoven fabric of this invention, the paper machine used when manufacturing a general paper can be applied easily. As the paper machine, in addition to continuous paper machines such as a long-mesh type, a circular net type, and an inclined type, a multi-layered paper machine combining these can be applied.

(Function and effect)
The method for producing a non-woven fabric is a method for producing a non-woven fabric by dehydrating the fine fibrous cellulose-containing slurry 3a produced by the production method above and drying it to improve the yield of the non-woven fabric relative to the fiber raw material. Can do.

Moreover, since the nonwoven fabric obtained by the said nonwoven fabric manufacturing method has a moderate space | gap, the resin impregnation property of a matrix material when obtaining a composite_body | complex with a matrix material is favorable. Furthermore, when the nonwoven fabric of this invention is used, the yellowishness of the composite obtained will become low, sufficient reinforcement effect will be expressed, and linear thermal expansion will become low.
Moreover, the nonwoven fabric of this invention can also be used alone. For example, it can be suitably used for filter members, battery separators, and the like by taking advantage of the fine structure unique to fine fibers.

(Chemical modification treatment)
In the present invention, chemical modification treatment may be applied to cellulose. Here, the chemical modification is to add a chemical modifier to a hydroxy group in cellulose by reacting it. The chemical modification treatment may be performed at any point in the production of the fine fibrous cellulose, may be performed on the fiber raw material, may be performed on the phosphate group-introduced cellulose, or may be performed on the alkali-treated cellulose. It may be applied to the nonwoven fabric. Moreover, you may perform a chemical modification process simultaneously with a phosphate group introduction | transduction process.

  As functional groups to be introduced into cellulose by chemical modification, acetyl group, acryloyl group, methacryloyl group, propionyl group, propioroyl group, butyryl group, 2-butyryl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, Decanoyl group, undecanoyl group, dodecanoyl group, myristoyl group, palmitoyl group, stearoyl group, pivaloyl group, benzoyl group, naphthoyl group, nicotinoyl group, isonicotinoyl group, furoyl group, acyl group such as cinnamoyl group, 2-methacryloyloxyethylisocyanoyl Isocyanate group such as a group, methyl group, ethyl group, propyl group, 2-propyl group, butyl group, 2-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, noni Group, decyl group, undecyl group, dodecyl group, myristyl group, palmityl group, an alkyl group such as a stearyl group, an oxirane group, an oxetane group, a thiirane group, or the like thietane group. Among these, an acyl group having 2 to 12 carbon atoms such as an acetyl group, an acryloyl group, a methacryloyl group, a benzoyl group and a naphthoyl group, and an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group and a propyl group are preferable. .

  The modification method is not particularly limited, and there is a method of reacting cellulose fibers with the following chemical modifier. Although there are no particular limitations on the reaction conditions, a solvent, a catalyst, or the like may be used, or heating, decompression, or the like may be performed as necessary.

  As a kind of chemical modifier, 1 type, or 2 or more types chosen from the group which consists of cyclic ethers, such as an acid, an acid anhydride, alcohol, a halogenating reagent, isocyanate, alkoxysilane, and an oxirane (epoxy), are mentioned.

Examples of the acid include acetic acid, acrylic acid, methacrylic acid, propanoic acid, butanoic acid, 2-butanoic acid, and pentanoic acid.
Examples of the acid anhydride include acetic anhydride, acrylic anhydride, methacrylic anhydride, propanoic anhydride, butanoic anhydride, 2-butanoic anhydride, and pentanoic anhydride.
Examples of the halogenating reagent include acetyl halide, acryloyl halide, methacryloyl halide, propanoyl halide, butanoyl halide, 2-butanoyl halide, pentanoyl halide, benzoyl halide, and naphthoyl halide.
Examples of the alcohol include methanol, ethanol, propanol, and 2-propanol.
Examples of the isocyanate include methyl isocyanate, ethyl isocyanate, propyl isocyanate, and the like.
Examples of the alkoxysilane include methoxysilane and ethoxysilane.
Examples of cyclic ethers such as oxirane (epoxy) include ethyl oxirane and ethyl oxetane.
Among these, acetic anhydride, acrylic acid anhydride, methacrylic acid anhydride, benzoyl halide, and naphthoyl halide are particularly preferable.
These chemical modifiers may be used alone or in combination of two or more.

  As the catalyst, it is preferable to use a basic catalyst such as pyridine, triethylamine, sodium hydroxide or sodium acetate, or an acidic catalyst such as acetic acid, sulfuric acid or perchloric acid.

  As the temperature condition for the chemical modification, if it is too high, there is a concern about yellowing of cellulose or a decrease in the degree of polymerization, and if it is too low, the reaction rate decreases, so 10 to 250 ° C. is preferable. Although the reaction time depends on the chemical modifier and the chemical modification rate, it is usually from several minutes to several tens of hours.

In the present invention, the chemical modification rate of cellulose is usually 65 mol% or less, preferably 50 mol% or less, more preferably 40 mol% or less, based on the total hydroxy groups of cellulose. There is no particular lower limit of the chemical modification rate.
By performing chemical modification, the decomposition temperature of cellulose increases and the heat resistance increases, but if the chemical modification rate is too high, the cellulose structure is destroyed and the crystallinity is lowered. The thermal expansion coefficient tends to increase, which is not preferable.

  The chemical modification rate as used herein refers to the proportion of all hydroxy groups in cellulose that have been chemically modified. The chemical modification rate can be determined by IR, NMR, titration methods, and the like. For example, the chemical modification rate of the ester can be measured by the following titration method.

0.05 g of dry cellulose is precisely weighed, and 1.5 ml of ethanol and 0.5 ml of distilled water are added thereto. This is left to stand in a hot water bath at 60 to 70 ° C. for 30 minutes, and then 2 ml of 0.5N aqueous sodium hydroxide solution is added. After leaving this in a 60-70 degreeC hot water bath for 3 hours, it ultrasonically shakes for 30 minutes with an ultrasonic cleaner. This is titrated with 0.2N hydrochloric acid standard solution using phenolphthalein as an indicator.
Here, from the amount Z (ml) of the 0.2N aqueous hydrochloric acid solution required for the titration, the number of moles Q of the substituent introduced by chemical modification is obtained by the following formula.
Q (mol) = 0.5 (N) × 2 (ml) /1000−0.2 (N) × Z (ml) / 1000
Here, the introduction amount of the carboxy group before chemical modification is A mmol / g, a mol%, the molecular weight of the substituent is S, and the introduction amount of the chemical modification group is B mmol / g, b mol%, the substituent. Assuming that the molecular weight of T is A, Ammol / g is calculated by the above method, and a mol% is calculated from Ammol / g by the following formula (I).
On the other hand, Bmmo / g is calculated from Q and A by the following formula (II).
B (mmol / g) = (Q × 1000) / sample amount−2A (II)
Further, Bmmol / g and b mol% are in the relationship of the following formula (III).
Therefore, b mol% is represented by the following formula (IV).

<Composite>
The composite of the present invention contains fine fibrous cellulose and a matrix material.

(Matrix material)
In the present invention, the matrix material is a material that fills voids between fine fibrous celluloses and, when fine fibrous cellulose forms a nonwoven fabric, preferably a polymer material.
Polymer materials suitable as the matrix material include thermoplastic resins, thermosetting resins (cured products obtained by polymerization and curing of thermosetting resin precursors by heating), and photocurable resins (precursors of photocurable resins). And a cured product obtained by polymerization and curing by irradiation with radiation (such as ultraviolet rays and electron beams). These may be one kind or two or more kinds.

  Although it does not specifically limit as a thermoplastic resin, Styrenic resin, acrylic resin, aromatic polycarbonate resin, aliphatic polycarbonate resin, aromatic polyester resin, aliphatic polyester resin, aliphatic polyolefin Resin, cyclic olefin resin, polyamide resin, polyphenylene ether resin, thermoplastic polyimide resin, polyacetal resin, polysulfone resin, amorphous fluorine resin and the like.

  The thermosetting resin is not particularly limited, but epoxy resin, acrylic resin, oxetane resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, silicon resin, polyurethane resin, diallyl phthalate resin, etc. Can be mentioned.

  Although it does not specifically limit as a photocurable resin, The epoxy resin illustrated as the above-mentioned thermosetting resin, an acrylic resin, an oxetane resin etc. are mentioned.

  Furthermore, specific examples of the thermoplastic resin, the thermosetting resin, and the photocurable resin include those described in JP-A-2009-299043.

The matrix material is preferably an amorphous synthetic polymer having a high glass transition temperature (Tg) from the viewpoint of obtaining a composite having excellent transparency and high durability. The degree of amorphousness is preferably 10% or less, particularly 5% or less in terms of crystallinity, and Tg is preferably 110 ° C. or higher, particularly 120 ° C. or higher, particularly 130 ° C. or higher. If Tg is low, there is a risk of deformation when touched with hot water, for example, which causes a practical problem. The Tg of the matrix material is obtained by measurement by the DSC method, and the crystallinity can be calculated from the density of the amorphous part and the crystalline part.
In order to obtain a low water-absorbing composite, the matrix material preferably has few hydrophilic functional groups such as a hydroxy group, a carboxy group, and an amino group.

The content of fine fibrous cellulose in the composite of the present invention is preferably 1% by mass to 99% by mass, and the content of the matrix material is preferably 1% by mass to 99% by mass. In order to exhibit low linear thermal expansibility, the content of fine fibrous cellulose is 1% by mass or more, and the content of matrix material is 99% by mass or less. It is preferable that the content of cellular cellulose is 99% by mass or less and the content of the matrix material is 1% by mass or more.
A more preferable range is a content of fine fibrous cellulose of 2% by mass or more and 90% by mass or less, a matrix material is 10% by mass or more and 98% by mass or less, and a more preferable range is a content of fine fibrous cellulose. Is 5% by mass or more and 80% by mass or less, and the content of the matrix material is 20% by mass or more and 95% by mass or less. In particular, in the composite of the present invention, the content of the fine fibrous cellulose is 70% by mass or less and the content of the matrix material is 30% by mass or more, and further, the content of the fine fibrous cellulose is 60% by mass or less. The content of the matrix material is preferably 40% by mass or more. Further, the content of the fine fibrous cellulose is 10% by mass or more and the content of the matrix material is 90% by mass or less. Furthermore, the content of the fine fibrous cellulose is 15% by mass or more and the content of the matrix material is 85% by mass. Hereinafter, it is further preferable that the content of the fine fibrous cellulose fiber is 20% by mass or more and the content of the matrix material is 80% by mass or less.

  The contents of the fine fibrous cellulose and the matrix material in the composite can be determined, for example, from the mass of the nonwoven fabric before the composite and the mass of the composite. Alternatively, the composite can be immersed in a solvent in which the matrix material is soluble to remove only the matrix material, and can be determined from the mass of the remaining fibers. In addition, the functional group derived from the matrix material or the cellulose fiber can also be quantitatively determined by using a method of determining from the specific gravity of the matrix material, NMR, or IR.

The composite of the present invention may be a flat film (film) or a flat plate, a film having a curved surface or a plate, or other three-dimensional shape. .
When the composite of the present invention is a film or a plate, the thickness is preferably 10 μm or more and 10 cm or less. Strength can be maintained by using a composite having such a thickness. The thickness of the composite is more preferably 50 μm or more and 1 cm or less, and further preferably 80 μm or more and 250 μm or less. Further, the thickness is not necessarily uniform, and may be partially different.

  Moreover, when the composite_body | complex of this invention is a film | membrane form or flat form, it is good also as a laminated body by stacking multiple sheets. Moreover, you may laminate | stack the composite sheet containing a cellulose fiber, and the resin sheet which does not contain a cellulose. A thick film can be formed by applying a heat press treatment to the laminate. The thick film composite can be suitably used as a glazing or structural material.

The composite of the present invention may be laminated with an inorganic film on the surface depending on the application. Examples of the inorganic material constituting the inorganic film include metals such as platinum, silver, aluminum, gold, and copper, silicon, ITO, SiO ₂ , SiN, SiOxNy, ZnO, and the like, and TFT. These combinations and film thicknesses can be designed arbitrarily.

(Production method of composite)
There is no restriction | limiting in particular as a method of manufacturing a composite_body | complex, For example, a composite_body | complex can be obtained with the following method.

(A) A method in which a nonwoven fabric is impregnated with a plastic resin precursor and polymerized.
(B) A method in which a nonwoven fabric is impregnated with a thermosetting resin precursor or a photocurable resin precursor and polymerized and cured.
(C) After impregnating a nonwoven fabric with a resin solution (a solution containing one or more solutes selected from a thermoplastic resin, a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor) and drying , A method of making it adhere with a heating press or the like, and polymerizing and curing as required.
(D) Method of impregnating non-woven fabric with thermoplastic resin melt and adhering with hot press etc. (e) Method of arranging thermoplastic resin sheets and non-woven fabric alternately and adhering with hot press etc. (f) Non-woven fabric A method in which a liquid thermoplastic resin precursor, a thermosetting resin precursor or a photocurable resin precursor is applied to one side or both sides and polymerized and cured.
(G) Applying a resin solution (a solution containing one or more solutes selected from a thermoplastic resin, a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor) to one side or both sides of the nonwoven fabric. Then, after removing the solvent, a method of polymerizing and curing as necessary.
(H) a fine fibrous cellulose-containing slurry and a monomer solution or dispersion (a solution containing one or more solutes or dispersoids selected from a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor, or Dispersion) and then solvent removal and polymerization curing.
(I) A method of removing the solvent after mixing the fine fibrous cellulose-containing slurry and the polymer solution or dispersion (thermoplastic resin solution or dispersion).

  (A) The nonwoven fabric is impregnated with a liquid thermoplastic resin precursor and polymerized. The nonwoven fabric is impregnated with a polymerizable monomer or oligomer, and the monomer is polymerized by heat treatment or the like to obtain a cellulose fiber composite. A method is mentioned. Generally, a polymerization catalyst used for polymerization of monomers can be used as a polymerization initiator.

  (B) As a method of polymerizing and curing a nonwoven fabric by impregnating a thermosetting resin precursor or a photocurable resin precursor, a thermosetting resin precursor such as an epoxy resin monomer, or a photocurable resin such as an acrylic resin monomer. A method of obtaining a cellulose fiber composite by impregnating a non-woven fabric with a mixture of a resin precursor and a curing agent and curing the thermosetting resin precursor or the photocurable resin precursor with heat or radiation or the like.

(C) After impregnating a nonwoven fabric with a resin solution (a solution containing one or more solutes selected from a thermoplastic resin, a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor) and drying As a method of closely adhering with a heating press or the like, and polymerizing and curing as necessary, there is a method of dissolving a resin in a solvent in which the resin is dissolved, impregnating the solution into a nonwoven fabric, and drying to obtain a cellulose fiber composite. Can be mentioned. In this case, a method of obtaining a higher-performance cellulose fiber composite by adhering the voids in which the solvent is dried by a heating press or the like after drying is mentioned. In the case of a photo-curing resin, polymerization curing by radiation or the like is further performed as necessary.
Here, the solvent for dissolving the resin may be selected according to the solubility of the resin.

  (D) As a method of impregnating a nonwoven fabric with a melt of a thermoplastic resin and closely adhering with a heating press or the like, the thermoplastic resin is dissolved by heat treatment at a glass transition temperature or higher or a melting point or higher, and impregnated into the nonwoven fabric. The method of obtaining a cellulose fiber composite by sticking with a heating press etc. is mentioned. The heat treatment is preferably performed under pressure, and the use of equipment having a vacuum heating press function is effective.

  (E) As a method of alternately arranging the thermoplastic resin sheets and the non-woven fabric and closely contacting with a hot press or the like, a thermoplastic resin film or sheet is arranged on one or both sides of the nonwoven fabric, and heating or pressing is performed as necessary. By doing, the method of bonding a thermoplastic resin and a nonwoven fabric is mentioned. In this case, an adhesive or a primer may be applied to the surface of the nonwoven fabric and bonded together. A method of passing between two pressurized rolls or a method of pressing in a vacuum state can be used so that bubbles are not embraced at the time of bonding.

  (F) As a method of applying and curing a liquid thermoplastic resin precursor, a thermosetting resin precursor or a photocurable resin precursor on one side or both sides of the nonwoven fabric, a thermal polymerization initiator is applied to one side or both sides of the nonwoven fabric. After applying a thermosetting resin precursor formulated with a photocuring resin precursor formulated with a photopolymerization initiator on one side or both sides of a nonwoven fabric, by curing by heating and curing both And a method of curing by irradiating with radiation such as ultraviolet rays. Alternatively, after applying a heat or photo-curing resin precursor to the nonwoven fabric, the nonwoven fabric may be further laminated and then cured.

(G) Applying a resin solution (a solution containing one or more solutes selected from a thermoplastic resin, a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor) to one side or both sides of the nonwoven fabric. Then, after removing the solvent, as a method of compounding by polymerizing and curing as necessary, a resin solution in which a resin soluble in the solvent is dissolved is prepared, applied to one or both sides of the nonwoven fabric, and heated. The method of removing a solvent is mentioned. In the case of a photo-curing resin, polymerization curing by radiation or the like is further performed as necessary.
What is necessary is just to select as a solvent which melt | dissolves resin according to the solubility of resin.

  (H) a fine fibrous cellulose-containing slurry and a monomer solution or dispersion (a solution containing one or more solutes or dispersoids selected from a thermoplastic resin precursor, a thermosetting resin precursor, and a photocurable resin precursor, or As a method of compounding by mixing the dispersion liquid) and then passing through the steps of solvent removal and polymerization and curing, a solution or dispersion liquid in which a solvent-soluble monomer is dissolved is prepared, and fine fibrous cellulose is prepared. Mix the slurry. At this time, it is preferable to use an organic solvent as a dispersion medium (solvent) in advance for defibration of the cellulose fiber as necessary, or to replace the water with an organic solvent when defibrated in water. A cellulose fiber composite can be obtained by polymerizing and curing the monomer in this mixed solution or polymerizing and curing the monomer after removing the solvent.

  (I) After mixing the fine fibrous cellulose-containing slurry and the polymer solution or dispersion (thermoplastic resin solution or dispersion), the solvent is removed to form a composite. Alternatively, a dispersion is prepared and mixed with the fine fibrous cellulose slurry. At this time, it is preferable to use an organic solvent as a dispersion medium (solvent) in advance for defibration of the cellulose fiber as necessary, or to replace the water with an organic solvent when defibrated in water. A cellulose fiber composite can be obtained by removing the solvent of the mixed solution.

  In the above thermoplastic resin precursor, thermosetting resin precursor, and photocurable resin precursor, a chain transfer agent, an ultraviolet absorber, a filler other than cellulose, a silane coupling agent, and the like are appropriately blended. Or a composition (hereinafter referred to as “curable composition”).

When the curable composition contains a chain transfer agent, the reaction can proceed uniformly. As the chain transfer agent, for example, a polyfunctional mercaptan compound having two or more thiol groups in the molecule can be used. By using a polyfunctional mercaptan compound, moderate toughness can be imparted to the cured product.
Examples of mercaptan compounds include pentaerythritol tetrakis (β-thiopropionate), trimethylolpropane tris (β-thiopropionate), and tris [2- (β-thiopropionyloxyethoxy) ethyl] triisocyanurate. It is preferable to use 1 type, or 2 or more types.
When a chain transfer agent is contained in the curable composition, the chain transfer agent is usually contained in a proportion of 30% by mass or less with respect to the total of radically polymerizable compounds in the curable composition.

When the curable composition contains an ultraviolet absorber, coloring can be prevented. The ultraviolet absorber is selected from, for example, a benzophenone ultraviolet absorber and a benzotriazole ultraviolet absorber, and one type of ultraviolet absorber may be used, or two or more types may be used in combination.
When an ultraviolet absorber is contained in the curable composition, the ultraviolet absorber is usually contained at a ratio of 0.01 to 1 part by mass with respect to a total of 100 parts by mass of radically polymerizable compounds in the curable composition. .

  Examples of the filler include inorganic particles and organic polymers. Specifically, inorganic particles such as silica particles, titania particles and alumina particles, transparent cycloolefin polymer particles such as Zeonex (Nippon Zeon) and Arton (JSR), general-purpose thermoplastics such as polycarbonate and polymethyl methacrylate Examples thereof include polymer particles. Among these, use of nano-sized silica particles is preferable because transparency can be maintained. In addition, when polymer particles having a structure similar to that of the ultraviolet curable monomer are used as the filler, the polymer can be dissolved to a high concentration, which is preferable.

Examples of the silane coupling agent include γ-((meth) acryloxypropyl) trimethoxysilane, γ-((meth) acryloxypropyl) methyldimethoxysilane, and γ-((meth) acryloxypropyl) methyldiethoxy. Examples include silane, γ-((meth) acryloxypropyl) triethoxysilane, and γ- (acryloxypropyl) trimethoxysilane. These have a (meth) acryl group in the molecule and are preferable because they can be copolymerized with other monomers.
When the curable composition contains a silane coupling agent, the silane coupling agent is usually 0.1 to 50% by mass, preferably 1 to 20%, based on the total of radically polymerizable compounds in the curable composition. It is made to contain so that it may become mass%. If the blending amount is too small, the effect of containing it is not sufficiently obtained, and if it is too large, optical properties such as transparency of the cured product may be impaired.

The curable composition can be polymerized and cured by a known curing method to obtain a cured product.
Examples of the curing method include thermal curing and radiation curing, and radiation curing is preferable. Examples of the radiation include infrared rays, visible rays, ultraviolet rays, electron beams, and the like, and light that is preferably electromagnetic waves having a wavelength of 1 to 1000 nm. More preferably, the electromagnetic wave has a wavelength of about 200 nm to 450 nm, and still more preferably ultraviolet light has a wavelength of 300 to 400 nm.

  As a specific curing method of the curable composition, a method in which a thermal polymerization initiator that generates radicals and acids by heating is added to the curable composition in advance and polymerized by heating (hereinafter referred to as “thermal polymerization”). In some cases, a photopolymerization initiator that generates radicals and acids by radiation such as ultraviolet rays is added to the curable composition in advance and polymerized by irradiation with radiation (preferably light) (hereinafter referred to as “light”). In some cases, it is referred to as “polymerization.”), A method in which both a thermal polymerization initiator and a photopolymerization initiator are added in advance, and polymerization is performed by a combination of heat and light.

When polymerizing and curing by radiation irradiation, the amount of radiation to be irradiated is arbitrary as long as the photopolymerization initiator is in a range that generates radicals. However, when the amount is extremely small, the polymerization becomes incomplete, so that the heat resistance and mechanical properties of the cured product are not sufficiently exhibited. Therefore, depending on the monomer composition and the type and amount of the photopolymerization initiator, 300 to 450 nm ultraviolet light is preferably in the range of 0.1 to 200 J / cm ² , more preferably in the range of 1 to ²⁰ J / cm ² . Irradiate with.
Moreover, it is more preferable to irradiate the radiation divided into a plurality of times. That is, when the first irradiation is performed for about 1/20 to 1/3 of the total irradiation amount and the necessary remaining amount is irradiated for the second and subsequent times, a cured product with smaller birefringence is obtained.
Specific examples of lamps used for radiation irradiation include metal halide lamps, high pressure mercury lamp lamps, ultraviolet LED lamps, electrodeless mercury lamps and the like.

  In order to quickly complete the polymerization and curing, photopolymerization and thermal polymerization may be performed simultaneously. In this case, curing is performed by heating the curable composition in the range of 30 to 300 ° C. simultaneously with the irradiation of radiation. In addition, a thermal polymerization initiator may be added to the curable composition in order to complete the polymerization, but when added in a large amount, the birefringence of the cured product is increased and the hue is deteriorated. Therefore, it is preferable that the addition amount of a thermal polymerization initiator is 0.1-2 mass% with respect to the sum total of a curable monomer component, and it is more preferable that it is 0.3-1 mass%.

Examples of the thermal polymerization initiator used for thermal polymerization include hydroperoxide, dialkyl peroxide, peroxy ester, diacyl peroxide, peroxy carbonate, peroxy ketal, and ketone peroxide. Specifically, benzoyl peroxide, diisopropyl peroxy carbonate, t-butyl peroxy (2-ethylhexanoate) dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, t-butyl hydroperoxide Side, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide and the like can be used. These polymerization initiators may be used alone or in combination of two or more.
When thermal polymerization is initiated at the time of light irradiation, it becomes difficult to control the polymerization. Therefore, the thermal polymerization initiator preferably has a 1 minute half-life temperature of 120 ° C. or higher.

  As the photopolymerization initiator used for photopolymerization, a photoradical generator or a photocationic polymerization initiator is usually used. A photoinitiator may be used independently or may use 2 or more types together.

  As the photoradical generator, a known compound that can be used for this purpose can be used. Examples include benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like. Among these, benzophenone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferable.

  A photocationic polymerization initiator is a compound that initiates cationic polymerization upon irradiation with radiation such as ultraviolet rays or electron beams, and includes the following.

  For example, aromatic sulfonium salts include bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate, bis [4- (diphenylsulfone). Nio) phenyl] sulfide bishexafluoroborate, bis [4- (diphenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluoro, diphenyl-4- (phenylthio) ) Phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) phenyls Phonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- (di ( 4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimony Bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide tetrafluoroborate, bis [4- (di (4- (2 Hydroxyethoxy)) phenylsulfonyl O) phenyl] sulfide tetrakis (pentafluorophenyl) borate, and the like.

  Aromatic iodonium salts include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecyl) Phenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluorophosphate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium hexafluoroborate 4-methylphenyl-4- (1-methylethyl) phenyl iodonium tetrakis (pentafluorophenyl) borate, and the like.

  Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, and the like.

  Examples of aromatic ammonium salts include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2- Cyanopyridinium tetrakis (pentafluorophenyl) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) -2- Cyanopyridinium tetrafluoroborate, 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate, (2,4-cyclopentadien-1-yl) [(1-methy Ethyl) benzene] -iron salts include (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) hexafluorophosphate, (2,4-cyclopentadiene-1- Yl) [(1-methylethyl) benzene] -iron (II) hexafluoroantimonate, (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) tetrafluoroborate (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -iron (II) tetrakis (pentafluorophenyl) borate and the like.

  Commercially available products of these cationic photopolymerization initiators include, for example, UVI6990, UVI6979 manufactured by Union Carbide, SP-150, SP-170, SP-172 manufactured by ADEKA, Irgacure 261 manufactured by Ciba Geigy, Irgacure 250, Examples include RHODORSIL PI2074, JMF-2456 manufactured by Rhodia, Sun Aid SI-60L, SI-80L, SI-100L, SI-110L, SI-180L, SI-100L, and the like manufactured by Sanshin Chemical Industry.

  Furthermore, in addition to the cationic photopolymerization initiator, a curing agent for curing the cationic polymerizable monomer may be added. Examples of the curing agent include amine compounds, compounds such as polyaminoamide compounds synthesized from amine compounds, tertiary amine compounds, imidazole compounds, hydrazide compounds, melamine compounds, acid anhydrides, phenol compounds, thermal latent cationic polymerization catalysts. , Dicyanamide and derivatives thereof. These hardening | curing agents may be used independently and 2 or more types may be used together. Among these, as the heat latent cationic polymerization catalyst, Adeka Opton CP-66, CP-77 (manufactured by ADEKA), Sun-Aid SI-15, SI-20, SI-25, SI-40, SI-45 SI-47, SI-60, SI-80, SI-100, SI-100L, SI-110L, SI-145, SI-150, SI-160, SI-180L (manufactured by Sanshin Chemical Industry Co., Ltd.) ) And the like.

  Moreover, a photosensitizer can also be added. Specific examples include pyrene, perylene, acridine orange, thioxanthone, 2-chlorothioxanthone, and benzoflavin. Examples of commercially available photosensitizers include Adekapitomer SP-100 (manufactured by ADEKA Corporation).

The component amount of the photopolymerization initiator is preferably 0.001 part by mass or more and 0.01 part by mass or more when the total amount of polymerizable compounds in the curable composition is 100 parts by mass. Is more preferably 0.05 parts by mass or more. The upper limit is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, and further preferably 0.1 parts by mass or less.
However, when the photopolymerization initiator is a photocationic polymerization initiator, it is 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably, with respect to 100 parts by mass of the total amount of the cationic polymerizable monomer. 0.5 parts by mass or more. The upper limit is usually 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 1 part by mass or less.
When the addition amount of the photopolymerization initiator is too large, the polymerization proceeds rapidly, not only increasing the birefringence of the resulting cured product but also deteriorating the hue. For example, when the concentration of the photopolymerization initiator is 5 parts by mass, absorption of the photopolymerization initiator causes light to not reach the side opposite to the irradiation of ultraviolet rays, resulting in an uncured part. Further, it is colored yellow and the hue is markedly deteriorated. On the other hand, if the amount is too small, the polymerization may not proceed sufficiently even if ultraviolet irradiation is performed.

In the production of the composite, when the nonwoven fabric of the present invention and the matrix material are composited, it is preferable to perform the above-described chemical modification treatment on the nonwoven fabric before the composite of the matrix material.
When chemically modifying the fine fibrous cellulose of the nonwoven fabric, the nonwoven fabric may be substituted with an organic solvent such as alcohol and dried, and then the chemical modification may be performed, or the chemical modification may be performed without drying. Since the reaction rate of chemical modification becomes faster after drying, it is preferable. Drying may be air drying, vacuum drying, or pressure drying. Moreover, you may heat.

  When the nonwoven fabric is chemically modified, it is preferable to wash the nonwoven fabric sufficiently after the chemical modification in order to terminate the reaction. If the unreacted chemical modifier remains, it is not preferable because it causes coloring later or becomes a problem when it is combined with the resin. In addition, after washing sufficiently, it is preferable to further replace with an organic solvent such as alcohol. In this case, the nonwoven fabric can be easily replaced by immersing it in an organic solvent such as alcohol.

Moreover, when chemically modifying a nonwoven fabric, the nonwoven fabric is normally dried after chemical modification. This drying may be air drying, vacuum drying, pressure drying, or heat drying.
When heating at the time of drying, the temperature is preferably 50 ° C or higher, more preferably 80 ° C or higher, 250 ° C or lower is more preferable, and 150 ° C or lower is more preferable. If the heating temperature is too low, drying may take time or drying may be insufficient, and if the heating temperature is too high, the nonwoven fabric may be colored or decomposed.
In addition, when pressurizing, the pressure (gauge pressure) is preferably 0.01 MPa or more, more preferably 0.1 MPa or more, and preferably 5 MPa or less, more preferably 1 MPa or less. If the pressure is too low, drying may be insufficient, and if the pressure is too high, the nonwoven fabric may be crushed or decomposed.

(Physical properties of the composite)
Next, the physical properties of the composite of the present invention will be described.

The composite of the present invention has a yellowness (YI value) of 30 or less measured in accordance with JIS standard K7105 after heating a fiber composite having a thickness of 100 μm for 1 hour at 190 ° C. with an oxygen partial pressure of 0.006 MPa or less. It is preferable that The yellowness is more preferably 25 or less.
The yellowness of the composite can be measured using, for example, a color computer manufactured by Suga Test Instruments.
The yellowness of the composite can be reduced by chemically modifying the cellulose fiber or using a highly transparent matrix material.

In the composite of the present invention, fibers having a fiber diameter thinner than the wavelength of visible light are used. Therefore, if a highly transparent material is used for the matrix material, a composite with high transparency, that is, low haze is obtained. Can do. The haze value of the composite is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less, as measured according to JIS standard K7136 for a composite having a thickness of 100 μm. It is particularly preferred that
The haze of the composite can be measured, for example, with a haze meter manufactured by Suga Test Instruments, and the value of C light is used.

  The composite of the present invention has a low water absorption, but in a 100 μm thickness, the water absorption measured in accordance with JIS standard K7209 (D method) is preferably 1% or less, 0.8 % Or less is more preferable, 0.5% or less is further preferable, and 0.3% or less is particularly preferable. When the water absorption rate exceeds 1%, the composite dehydrated in the processing process is undesirably stretched by absorbing moisture in the air and causing dimensional deformation when left in the air.

  The composite of the present invention has a thickness of 100 μm, and the total light transmittance measured in accordance with JIS standard K7105 in the thickness direction is preferably 60% or more, more preferably 70% or more, more preferably 80%. More preferably, it is 82% or more, more preferably 84% or more, still more preferably 86% or more, particularly preferably 88% or more, and particularly preferably 90% or more. If this total light transmittance is less than 60%, it becomes translucent or opaque, and it may be difficult to use it in applications requiring transparency. The total light transmittance can be measured, for example, using a Suga Test Instruments haze meter, and the value of C light is used.

  In the composite of the present invention having a thickness of 100 μm, the parallel light transmittance measured in accordance with JIS standard K7105 in the thickness direction is 57% or more, further 70% or more, particularly 80% or more, especially 89%. The above is preferable. If the parallel light transmittance is less than 57%, the amount of scattered light is increased and haze is increased. For example, in an organic EL device application, the pixel becomes unclear and the color is blurred or blurred. The parallel light transmittance can be measured, for example, using a Suga Test Instruments haze meter, and the value of C light is used.

  The composite of the present invention can easily reduce the linear thermal expansion coefficient, but the composite linear thermal expansion coefficient is preferably 1 to 50 ppm / K or less. The linear thermal expansion coefficient of the composite of the present invention is more preferably 30 ppm / K or less, and particularly preferably 20 ppm / K or less. Further, the linear thermal expansion coefficient is preferably 1 ppm / K or more, and more preferably 5 ppm / K or more. For example, in a substrate application, since the linear thermal expansion coefficient of an inorganic thin film transistor is about 15 ppm / K, when the composite has a linear thermal expansion coefficient of more than 50 ppm / K, two layers are combined in an inorganic film. The difference in coefficient of linear thermal expansion between layers becomes large, and cracks and the like occur. In addition, a linear thermal expansion coefficient is measured by the method described in the term of the below-mentioned Example.

  In the composite of the present invention, the matrix material is filled in the gaps between the fine fibrous celluloses, but when the nonwoven fabric is used, the matrix material is filled in the gaps of the nonwoven fabric. Therefore, the volume ratio of the matrix material filling portion is substantially equal to the porosity of the nonwoven fabric.

  The composite of the present invention has a tensile strength of preferably 40 MPa or more, more preferably 100 MPa or more. If the tensile strength is lower than 40 MPa, sufficient strength cannot be obtained, which may affect the use of a structural material or the like to which a force is applied.

The composite of the present invention preferably has a tensile modulus of 0.2 to 100 GPa, more preferably 1 to 100 GPa. When the tensile elastic modulus is lower than 0.2 GPa, sufficient strength cannot be obtained, which may affect the use in applications where force is applied such as structural materials.
In particular, in a display substrate application, there is a suitable range for the tensile elastic modulus of the substrate. If the tensile elastic modulus of the substrate is low, the substrate is bent by its own weight, and it becomes difficult to form a smooth surface. For this reason, transistors and other elements cannot be formed with high accuracy. On the other hand, if the tensile elastic modulus is too high, it becomes hard and brittle, causing problems such as cracking of the substrate itself.

The composite of the present invention has a low linear thermal expansion coefficient, high elasticity, and high strength. Taking advantage of the characteristics, the composite of the present invention can be used as a structural material. In particular, it is suitably used as automotive materials such as glazing, interior materials, outer plates, bumpers, etc., personal computer casings, home appliance parts, packaging materials, building materials, civil engineering materials, marine products, and other industrial materials.
Among the composites of the present invention, those having high transparency, high strength, low water absorption and small haze are excellent in optical characteristics, so that liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions are used. It is suitable as a display, a substrate or a panel. Moreover, it is suitable for substrates for solar cells such as silicon-based solar cells and dye-sensitized solar cells. For use as a substrate, it may be laminated with a barrier film, ITO, TFT or the like. Further, it is suitably used for window materials for automobiles, window materials for railway vehicles, window materials for houses, window materials for offices and factories, and the like. As a window material, you may laminate | stack films | membranes, such as a fluorine film and a hard-coat film | membrane, and an impact-resistant and light-resistant material as needed.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example show a mass part and mass%, respectively.

Example 1
10.14 g of sodium dihydrogen phosphate dihydrate and 1.79 g of disodium hydrogen phosphate are dissolved in 19.27 g of water, and an aqueous solution of a phosphoric acid compound (hereinafter referred to as “phosphorylation reagent A”) is obtained. Obtained. The pH of this phosphorylating reagent A was 4.73 at 25 ° C.
Softwood bleached kraft pulp (manufactured by Oji Paper Co., Ltd., water 50%, Canadian standard freeness (CSF) 700 ml measured according to JIS P8121) is added with water to a concentration of 4%, and an irregularity is made with a double disc refiner. Beating CSF (80 mesh plain weave, according to JIS P8121 except that the amount of collected pulp was 0.3 g) was beaten until 250 mm and the length average fiber length became 0.68 mm, to obtain a pulp slurry. 3 g of the obtained pulp slurry was collected at an absolutely dry mass, diluted to 0.3% with ion-exchanged water, and then dehydrated by a papermaking method to obtain a pulp sheet. The obtained pulp sheet had a moisture content of 90% and a thickness of 200 μm. This pulp sheet was immersed in 31.2 g of the phosphorylating reagent A (80.2 parts by mass as phosphorus element amount with respect to 100 parts by mass of dried pulp), and 2 hours by a 170 ° C. blower dryer (Yamato Scientific Co., Ltd. DKM400). Half-heat treatment was performed to introduce a phosphorus oxoacid group into cellulose.
Next, 500 ml of ion-exchanged water was added to the cellulose into which the phosphorus oxo acid group had been introduced, and after stirring and washing, filtration and dehydration were performed to obtain a dehydrated sheet. The obtained dehydrated sheet was diluted with 300 ml of ion-exchanged water, and 5 ml of 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Then, this pulp slurry was dehydrated and washed by adding 500 ml of ion exchange water. This dehydration washing was further repeated twice to obtain a dehydrated sheet of cellulose containing phosphooxo acid.
Ion exchange water was added to the dehydrated sheet of phosphooxoacid-introduced cellulose obtained after washing and dehydration, and the mixture was stirred to make a slurry of 0.5% by mass. This slurry was defibrated for 30 minutes under a condition of 21,500 rotations / minute using a defibrating apparatus (M-Technic Co., Ltd., CLEARMIX-2.2S) to obtain a defibrated pulp slurry.
The defibrated pulp slurry is centrifuged in accordance with the method described below (centrifugation in the supernatant yield after centrifugation), and the supernatant is purified in accordance with the method described below ([transmission electron microscope observation]). And observed. Thereby, it was confirmed that it became the fine fibrous cellulose about 4 nm wide (FIG. 1). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed. Therefore, the obtained phosphoric acid oxoacid-introduced cellulose was one in which a part of the hydroxy group of the cellulose was substituted with the functional group of the following structural formula (2).

(Example 2)
In Example 1, a defibrated pulp slurry was obtained in the same manner as in Example 1 except that the pH of the phosphorylating reagent A at 25 ° C. was adjusted to pH 6.0 with a 1N aqueous sodium hydroxide solution.
The defibrated pulp slurry was centrifuged as in Example 1, and the supernatant was observed and measured with a transmission electron microscope. It was confirmed to be fine fibrous cellulose having a width of about 4 nm (not shown). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

(Example 3)
In Example 2, the pulp sheet was defibrated in the same manner as in Example 2 except that the pulp sheet was heat-treated at 105 ° C. for 1 hour and then at 150 ° C. for 1 hour with a blow dryer (Yamato Scientific Co., Ltd. DKM400). Got.
The defibrated pulp slurry was centrifuged as in Example 1, and the supernatant was observed and measured with a transmission electron microscope. It was confirmed to be a fine fibrous cellulose having a width of about 4 nm (FIG. 2). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

Example 4
In Example 3, 0.51 g of sodium dihydrogen phosphate dihydrate and 0.09 g of disodium hydrogen phosphate were dissolved in 30.6 g of water, and an aqueous solution of a phosphoric acid compound (hereinafter referred to as “phosphorylation reagent”). B "). A defibrated pulp slurry was obtained in the same manner as in Example 3 except that this phosphorylating reagent B was used to introduce a phosphoroxo acid group into cellulose.
The defibrated pulp slurry was centrifuged as in Example 1, and the supernatant was observed and measured with a transmission electron microscope. Thereby, it was confirmed that it was a fine fibrous cellulose having a width of about 4 nm (not shown). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

(Example 5)
A defibrated pulp slurry was obtained in the same manner as in Example 3 except that the alkali treatment step was omitted.

(Example 6)
6.75 g of sodium dihydrogen phosphate dihydrate and 4.83 g of disodium hydrogen phosphate were dissolved in 19.62 g of water, and an aqueous solution of a phosphoric acid compound (hereinafter referred to as “phosphorylation reagent C”). Obtained. The pH of this phosphorylating reagent C was 6.0 at 25 ° C.
Conifer unbleached kraft pulp (manufactured by Oji Paper Co., Ltd., moisture 50%, Canadian standard freeness (CSF) 700 ml measured according to JIS P8121) is added with water to a concentration of 4%, and double disc refiner is used. Anomalous CSF (80 mesh plain weave, according to JIS P8121 except that the amount of pulp collected was 0.3 g) was beaten until 200 ml and the length average fiber length became 0.66 mm, to obtain a pulp slurry. 3 g of the obtained pulp slurry was collected at an absolutely dry mass, diluted to 0.3% with ion-exchanged water, and then dehydrated by a papermaking method to obtain a pulp sheet. The obtained pulp sheet had a moisture content of 90% and a thickness of 200 μm.
This pulp sheet was immersed in 31.2 g of the phosphorylating reagent C (80.2 parts by mass as the amount of phosphorus element with respect to 100 parts by mass of the dried pulp), and 1 hour by a fan dryer at 105 ° C. (Yamato Scientific Co., Ltd. DKM400). After heating, heat treatment was further performed at 150 ° C. for 1 hour to introduce a phosphorus oxo acid group into cellulose.
Next, 500 ml of ion-exchanged water was added to the cellulose into which the phosphorus oxo acid group had been introduced, and after stirring and washing, filtration and dehydration were performed to obtain a dehydrated sheet. The obtained dehydrated sheet was diluted with 300 ml of ion-exchanged water, and 5 ml of 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Then, this pulp slurry was dehydrated and washed by adding 500 ml of ion exchange water. This dehydration washing was further repeated twice to obtain a dehydrated sheet of cellulose containing phosphooxo acid.
Ion exchange water was added to the dehydrated sheet of phosphooxoacid-introduced cellulose obtained after washing and dehydration, and the mixture was stirred to make a slurry of 0.5% by mass. This slurry was defibrated for 30 minutes under a condition of 21,500 rotations / minute using a defibrating apparatus (M-Technic Co., Ltd., CLEARMIX-2.2S) to obtain a defibrated pulp slurry.
The defibrated pulp slurry is centrifuged in accordance with the method described below (centrifugation in the supernatant yield after centrifugation), and the supernatant is purified in accordance with the method described below ([transmission electron microscope observation]). And observed. Thereby, it was confirmed that it was a fine fibrous cellulose having a width of about 4 nm (not shown). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

(Example 7)
Softwood bleached kraft pulp (manufactured by Oji Paper Co., Ltd., water 50%, Canadian standard freeness (CSF) 700 ml measured according to JIS P8121) is added with water to a concentration of 4%, and an irregularity is made with a double disc refiner. Beating CSF (plain mesh 80 mesh, according to JIS P8121 except that the amount of pulp collected was 0.3 g) was beaten until the average fiber length was 0.66 mm to obtain a pulp slurry. The obtained pulp slurry was concentrated to 13% solid content with a centrifugal dehydrator. 1000 g of the concentrated pulp slurry is put in a container of a biaxial kneader equipped with a steam heating jacket container, and then 72.04 g of sodium dihydrogen phosphate dihydrate and 53.58 g of disodium hydrogen phosphate are in powder form. Added (20 parts by mass as phosphorus element amount to 100 parts by mass of dry pulp) and mixed for 15 minutes. After mixing, steam was introduced into the jacket and dried at an internal temperature of 70 ° C. until the solid content reached 99%. The obtained dried product was heat-treated for 1 hour with a 150 ° C. blow dryer (Yamato Scientific Co., Ltd., DKM400) to introduce a phosphorus oxo acid group into the cellulose.
Subsequently, 3 g of cellulose into which a phosphorooxy acid group was introduced was collected, 500 ml of ion exchange water was added, and after stirring and washing, filtration and dehydration were performed to obtain a dehydrated sheet. The obtained dehydrated sheet was diluted with 300 ml of ion-exchanged water, and 5 ml of 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Then, this pulp slurry was dehydrated and washed by adding 500 ml of ion exchange water. This dehydration washing was further repeated twice to obtain a dehydrated sheet of cellulose containing phosphooxo acid.
Ion exchange water was added to the dehydrated sheet of phosphooxoacid-introduced cellulose obtained after washing and dehydration, and the mixture was stirred to make a slurry of 0.5% by mass. This slurry was defibrated for 30 minutes under a condition of 21,500 rotations / minute using a defibrating apparatus (M-Technic Co., Ltd., CLEARMIX-2.2S) to obtain a defibrated pulp slurry.
The defibrated pulp slurry is centrifuged in accordance with the method described below (centrifugation in the supernatant yield after centrifugation), and the supernatant is purified in accordance with the method described below ([transmission electron microscope observation]). And observed. Thereby, it was confirmed that it was a fine fibrous cellulose having a width of about 4 nm (not shown). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

(Example 8)
1.69 g of sodium dihydrogen phosphate dihydrate and 1.21 g of disodium hydrogen phosphate are dissolved in 3.39 g of water, and an aqueous solution of a phosphoric acid compound (hereinafter referred to as “phosphorylation reagent D”) is obtained. Obtained. The pH of this phosphorylating reagent D was 6.0 at 25 ° C.
Softwood bleached kraft pulp (manufactured by Oji Paper Co., Ltd., moisture 50%, Canadian standard freeness (CSF) 700 ml measured according to JIS P8121) is diluted with ion-exchanged water to a moisture content of 80%, and the pulp slurry is Obtained. 6.15 g of the phosphorylating reagent D (20 parts by mass as the amount of phosphorus element with respect to 100 parts by mass of dry pulp) is added to 15 g of this pulp slurry, and once every 15 minutes with an air dryer at 105 ° C. (Yamato Scientific Co., Ltd. DKM400). It was dried until the mass became constant while kneading. Subsequently, it heat-processed with the ventilation drying machine of 150 degreeC for 1 hour, and the phosphorus oxo acid group was introduce | transduced into the cellulose.
Next, 500 ml of ion-exchanged water was added to the cellulose into which the phosphorus oxo acid group had been introduced, and after stirring and washing, dehydration was performed. The pulp after dehydration was diluted with 300 ml of ion-exchanged water, and 5 ml of 1N aqueous sodium hydroxide solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Then, this pulp slurry was dehydrated and washed by adding 500 ml of ion exchange water. This dehydration washing was repeated two more times.
Ion exchange water was added to the pulp obtained after washing and dewatering, and the mixture was stirred to make a slurry of 0.5% by mass. This pulp slurry was defibrated for 30 minutes under a condition of 21500 rotations / minute using a defibrating apparatus (Cleamix-2.2S, manufactured by M Technique Co., Ltd.) to obtain a defibrated pulp slurry.
The defibrated pulp slurry is centrifuged in accordance with the method described below (centrifugation in the supernatant yield after centrifugation), and the supernatant is purified in accordance with the method described below ([transmission electron microscope observation]). And observed. Thereby, it was confirmed that it was a fine fibrous cellulose having a width of about 4 nm (not shown). In addition, by X-ray diffraction, cellulose maintains cellulose I-type crystals. Absorption based on a phosphate group is observed at 1230 to 1290 cm ⁻¹ by measurement of an infrared absorption spectrum by FT-IR. The addition was confirmed.

(Comparative Example 1)
In Example 1, a defibrated pulp slurry was obtained in the same manner as in Example 1 except that heating was performed without adding the phosphorylating reagent A, alkali treatment followed by defibrating treatment.

(Comparative Example 2)
In Example 2, a defibrated pulp slurry was obtained in the same manner as in Example 2 except that heating was performed without adding the phosphorylating reagent A and alkali treatment was omitted.

(Comparative Example 3)
In Example 6, a defibrated pulp slurry was obtained in the same manner as in Example 6 except that heating was performed without adding the phosphorylating reagent C and the fibrillation treatment was performed after alkali treatment.

<Evaluation>
About the defibrated pulp slurry of the said Examples 1-8 and Comparative Examples 1-3, the supernatant yield after centrifuging was measured by the method as described below. The measurement results are shown in Table 1. The supernatant yield after centrifugation is an indicator of the yield of fine fibrous cellulose, and the higher the supernatant yield, the higher the yield of fine fibrous cellulose.
Further, the amount of phosphate group or polyphosphate group introduced into cellulose was measured by the method described above. The results are also shown in Table 1.

[Measurement of supernatant yield after centrifugation]
Ion exchange water is added to the defibrated pulp slurry to adjust the slurry solid content concentration to 0.2% by mass, and the mixture is centrifuged at 12000 G × 10 min using a cooling high-speed centrifuge (Kokusan, H-2000B). The obtained supernatant was recovered, and the solid content concentration of the supernatant was measured. Based on the following formula, the yield of fine fibrous cellulose was determined.
Yield (%) of fine fibrous cellulose = solid content concentration of supernatant / 0.2% by mass × 100

[Transmission electron microscope observation]
The supernatant liquid of the defibrated pulp slurry was diluted with water to a concentration of 0.01 to 0.1% by mass and dropped onto a hydrophilic carbon grid membrane. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.).

In Examples 1 to 8, in which the pulp was treated with the phosphorus oxo acid group-containing compound and then defibrated, the supernatant yield after centrifugation was high and the fine fibrous cellulose yield was high.
In Comparative Examples 1 to 3 in which the treatment with the phosphorus oxo acid group-containing compound was omitted, the supernatant yield after centrifugation was low and the fine fibrous cellulose yield was low.

<Manufacture of non-woven fabric>
Example 9
The slurry containing fine fibrous cellulose obtained in Example 3 was diluted with water to a cellulose concentration of 0.127% by mass, adjusted to 150 ml, and gently 30 ml of isopropyl alcohol (IPA) was gently added from above the liquid. In addition, vacuum filtration was performed. KG-90 made by Advantech was used as a filter, and a PTFE membrane filter made by Advantech having a pore size of 1.0 μm was placed on the glass filter. The effective filtration area was 48 cm ² . When filtration under reduced pressure was performed at a reduced pressure of -0.09 MPa (absolute vacuum of 10 kPa), a cellulose fiber deposit was obtained on the PTFE membrane filter. This cellulose deposit was press-dried at a pressure of 0.15 MPa for 5 minutes with a press machine heated to 120 ° C. to obtain a porous nonwoven fabric.

(Example 10)
A nonwoven fabric was obtained in the same manner as in Example 9 except that the supernatant after centrifugation of the fine fibrous cellulose-containing slurry obtained in Example 3 was used.

(Evaluation)
About the nonwoven fabric of said Examples 9-10, the chemical modification rate of the cellulose, the porosity, and the yellowness were measured by the method as described below. The measurement results are shown in Table 2.

[Porosity of nonwoven fabric]
It calculated | required by the following formula from the area, thickness, and mass of the nonwoven fabric.
Porosity (vol%) = {(1-B / (M × A × t)} × 100
Here, A is the area (cm ² ) of the nonwoven fabric, t (cm) is the thickness, B is the mass (g) of the nonwoven fabric, M is the density of cellulose, and M = 1.5 g / cm ³ is assumed in the present invention. did. The film thickness of the nonwoven fabric was measured at 10 points for various positions of the nonwoven fabric using a film thickness meter (IP65 manufactured by Mitutoyo Co., Ltd.), and the average value was adopted.

[Yellowness of non-woven fabric]
The obtained nonwoven fabric was heated at 190 ° C. under vacuum (oxygen partial pressure 0.006 MPa) for 1 hour, and then the yellowness was measured using a color computer manufactured by Suga Test Instruments in accordance with JIS standard K7105.

  All of the nonwoven fabrics of Examples 9 to 10 had an appropriate porosity and small yellowness.

(Example 11)
<Composite with resin matrix material>
100 parts by mass of 1,10-decanediol diacrylate, 0.02 parts by mass of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF “Lucirin TPO”), and the nonwoven fabric obtained in Example 9 A mixed solution of 0.01 part by mass of benzophenone was impregnated and left overnight under reduced pressure. The obtained cellulose fiber aggregate impregnated with the resin solution was sandwiched between two glass plates, and was cured with an ultraviolet ray using an electrodeless mercury lamp lamp (“D bulb” manufactured by Fusion UV Systems). Conditions of UV curing, irradiation intensity 400 mW / cm ² at a wavelength 365 nm, is semi-cured through the front and back twice in total to the line speed 7m / min, then the irradiation intensity at a wavelength of 365nm 1900mW / cm ^2, line speed 2m / The test was carried out under the condition of complete curing by passing the front and back two times (total 4 times) at min. After the ultraviolet irradiation, the glass plate was removed and heated in a vacuum oven at 190 ° C. for 1 hour to obtain a cellulose fiber composite having a thickness of 51 μm.
In addition, the irradiance of ultraviolet rays was measured at 23 ° C. by using an ultraviolet ray illuminance meter “UV-M02” manufactured by Oak Seisakusho and using an attachment “UV-35”.

(Example 12)
A cellulose fiber composite having a thickness of 84 μm was obtained in the same manner as in Example 11 except that the nonwoven fabric obtained in Example 10 was used.

(Comparative Example 4)
<Hardened material composed only of resin>
In Example 12, a non-woven fabric was not used, and only the photocurable resin was cured under the same conditions to produce a cured product of a resin having a thickness of 83 μm.

(Evaluation)
About the composite body of the said Examples 11-12 and the resin hardened | cured material of the comparative example 4, a tensile elasticity modulus, yellowness, a haze, a total light transmittance, a parallel light transmittance, a glass transition temperature, and a linear thermal expansion coefficient are described below. It measured by the method of. Table 3 shows the measurement results.

[Tensile modulus of composite]
The obtained composite was cut into a length of 10 mm × 40 mm with a laser cutter. Using a DMS6100 manufactured by SII, the chuck was 20 mm in chuck mode, the frequency was 10 Hz, and 2 ° C./min. The tensile elastic modulus was determined from the storage elastic modulus E ′ (unit: GPa) at 23 ° C. from −100 ° C. to 250 ° C.

[Haze of composite or cured resin]
Based on JIS standard K7136, the haze value by C light was measured using the haze meter by Suga Test Instruments.

[Total light transmittance of composite or cured resin]
Based on JIS standard K7105, the total light transmittance by C light was measured using the haze meter by Suga Test Instruments.

[Parallel light transmittance of composite or cured resin]
Based on JIS standard K7105, the parallel light transmittance by C light was measured using the haze meter by Suga Test Instruments.

[Linear thermal expansion coefficient of composite or cured resin]
The obtained composite was cut into 3 mm width × 30 mm length with a laser cutter. This was carried out by using TMA120 manufactured by SII in a tension mode at a temperature of 5 ° C./min. At 180 ° C. to 25 ° C. at 5 ° C./min. At 25 ° C to 180 ° C, 5 ° C / min. The linear thermal expansion coefficient was determined from the measured value from 60 ° C. to 100 ° C. at the time of the second temperature increase.

  The composites of Examples 11 to 12 had high transparency, high strength, and low linear thermal expansion.

DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus 3a Slurry containing fine fibrous cellulose 3b Hydrous web 3c Non-woven fabric 10 Paper making wire 20 Dehydration section 40 Drying section 60 Winding section

Claims (9)

(A) a step of treating a fiber raw material containing cellulose with at least one compound selected from phosphorus oxoacids or salts thereof while heating to 100 to 170 ° C . ;
(B) A method for producing fine fibrous cellulose, comprising a step of defibrating the cellulose treated in the step (a).   The method for producing fine fibrous cellulose according to claim 1, wherein the fiber raw material is a chemical pulp obtained from wood.   The method for producing fine fibrous cellulose according to claim 1 or 2, wherein at least one compound selected from the phosphorus oxoacids or salts thereof is a compound having a phosphate group.   A dehydration step of dehydrating a slurry containing fine fibrous cellulose produced by the method for producing fine fibrous cellulose according to any one of claims 1 to 3 on a filter medium to obtain a wet paper, and drying the wet paper A method for producing a nonwoven fabric, comprising: a drying step. Fine fibrous cellulose having a fiber width of 1 to 1000 nm and having a phosphorus oxo acid group introduced by substituting a part of the hydroxyl group of cellulose constituting the fiber with a functional group represented by the following structural formula (1) Because
A fine fibrous cellulose, wherein the introduction amount of a phosphorus oxoacid group is 0.1 to 2.0 mmol per 1 g of the fine fibrous cellulose.
In the structural formula (1), a, b, m, and n are natural numbers (provided that a = b × m). At least one of α ¹ , α ² ,..., α ⁿ and α ′ is O ⁻ , and the rest is either R or OR. R is a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group, respectively. One of a hydrogen group, an aromatic group, and a derivative group thereof. β is a monovalent or higher cation composed of an organic substance or an inorganic substance.   A fine fibrous cellulose-containing slurry obtained by dispersing the fine fibrous cellulose according to claim 5 in a dispersion medium.   A nonwoven fabric containing the fine fibrous cellulose according to claim 5.   A composite containing the fine fibrous cellulose according to claim 5 and a matrix material.   A composite comprising the nonwoven fabric according to claim 7 and a matrix material.