JP2018104567A - Sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine fibrous cellulose-containing sheet capable of molding a three-dimensional molding having both high dimensional stability and transferability (releasability).SOLUTION: A sheet contains a fibrous cellulose having a fiber width of 5,000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin.SELECTED DRAWING: None

Description

  The present invention relates to a sheet. Specifically, the present invention relates to a sheet containing fine fibrous cellulose.

  In recent years, materials that use reproducible natural fibers have attracted attention due to the substitution of petroleum resources and the growing environmental awareness. Among natural fibers, fibrous cellulose having a fiber diameter of 10 μm or more and 50 μm or less, in particular, fibrous cellulose (pulp) derived from wood has been widely used mainly as a paper product so far.

  As fibrous cellulose, fine fibrous cellulose having a fiber diameter of 5 μm or less is also known. In addition, a sheet composed of such fine fibrous cellulose, a composite sheet containing a fine fibrous cellulose-containing sheet and a resin, and a molded body have been developed. In the sheet | seat and molded object containing a fine fibrous cellulose, since the contact point of fibers increases remarkably, it is known that tensile strength etc. will improve large.

  For example, Patent Document 1 discloses an internally added paper in which a composite material in which organoalkoxysilane is supported on fine fibrous cellulose is internally added. Here, it is considered to produce a paper container such as a food tray using such an internal paper. Patent Document 2 discloses a composite material containing a resin emulsion such as fine fibrous cellulose and rubber latex. Here, it aims at manufacturing the composite material excellent in mechanical physical properties, such as breaking strength.

JP 2002-322313 A Japanese Patent Laying-Open No. 2015-093882

When molding a sheet containing fine fibrous cellulose, it is particularly required that the three-dimensional molded body has excellent dimensional stability. In addition, the three-dimensional molded body after molding is also required to be excellent in transferability (release property).
Therefore, the present inventors proceeded with studies for the purpose of providing a fine fibrous cellulose-containing sheet capable of forming a three-dimensional molded article having both high dimensional stability and transferability (release property).

As a result of intensive studies to solve the above problems, the present inventors have added a hydrophilic resin to at least one selected from a fluorine-containing compound and a siloxane bond-containing compound in a fine fibrous cellulose-containing sheet. It has been found that a fine fibrous cellulose-containing sheet capable of forming a three-dimensional molded article having both high dimensional stability and transferability (release property) can be obtained.
Specifically, the present invention has the following configuration.

[1] A sheet comprising fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin.
[2] The sheet according to [1], wherein the content of at least one selected from a fluorine-containing compound and a siloxane bond-containing compound is 5% by mass to 70% by mass with respect to the total mass of the sheet.
[3] The sheet according to [1] or [2], wherein the content of fibrous cellulose is 30% by mass or more and 90% by mass or less with respect to the total mass of the sheet.
[4] The sheet according to any one of [1] to [3], wherein the content of the hydrophilic resin is 5% by mass to 70% by mass with respect to the total mass of the sheet.
[5] The sheet according to any one of [1] to [4], which is a sheet for a three-dimensional molded body.
[6] A laminated sheet further having a resin layer on at least one surface side of the sheet according to any one of [1] to [5].
[7] The laminated sheet according to [6], wherein the resin layer includes at least one selected from a fluororesin, a silicone resin, an acrylic resin, a polycarbonate resin, a urethane resin, a polyethylene resin, and a polyvinyl alcohol resin.
[8] A three-dimensional molded body of the sheet according to any one of [1] to [5] or the laminated sheet according to [6] or [7].

  ADVANTAGE OF THE INVENTION According to this invention, the fine fibrous cellulose containing sheet which can shape | mold the three-dimensional molded object which has high dimensional stability and transferability (mold release property) can be obtained.

FIG. 1 is a graph showing the relationship between the amount of NaOH dripped with respect to the fiber material and the electrical conductivity. FIG. 2 is a graph showing the relationship between the amount of dropped NaOH and electrical conductivity for a fiber material having a carboxyl group.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

(Sheet)
The present invention relates to a sheet comprising fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin. In the present specification, fibrous cellulose having a fiber width of 5000 nm or less may be referred to as fine fibrous cellulose, and the sheet may be referred to as a fine fibrous cellulose-containing sheet.

  Since the sheet | seat of this invention has the said structure, the three-dimensional molded object which has high dimensional stability and transferability (mold release property) can be shape | molded.

  In the three-dimensional molding, molded bodies having various shapes can be molded. For example, it is preferable to mold a molded body having an uneven structure. The three-dimensional molding is preferably a nanoimprint capable of forming a fine concavo-convex structure, and more preferably a thermal nanoimprint. That is, the sheet of the present invention is preferably a three-dimensional molded sheet, more preferably a nanoimprint sheet, and still more preferably a thermal nanoimprint sheet. Nanoimprint is a technique for forming a nano-level uneven structure by pressing an original plate (such as a mold) against a sheet.

The three-dimensional molded body molded from the sheet of the present invention is excellent in dimensional stability. The dimensional stability of a three-dimensional molded product formed from a sheet is determined by how far the measured value of the width or height of the concavo-convex structure formed when nanoimprint molding is applied to the sheet differs from the reference design dimension. It can be evaluated by whether or not. Here, the nanoimprint molded body for evaluation is produced by the following procedure.
(1) A mold release spray is applied to the mold. As molds, manufactured by Cyvax, nanoimprint mold (model number: MTLS1 / 2 / 2-50 × 50), line and space type, silicon, specifications (width: 1 μm, height: 2 μm, pitch: 2 μm) Molding area: 50 mm × 50 mm and mold area 50 mm × 50 mm are used. As a mold release spray, an aerosol type spray (model number: MRF-6758-AL) manufactured by AGC Seikagaku Co., Ltd. is used.
(2) The sheet of the present invention is cut into 40 mm × 40 mm.
(3) A mold and a cut sheet are set in a press machine (manufactured by Aida Engineering Co., Ltd., 160 mm square mini test press with a cooler).
(4) After pressing at a pressure of 3 MPa and a temperature of 180 ° C. for 1 minute, the mold is cooled until the temperature of the mold reaches 30 ° C.
(5) The sheet is peeled from the mold to obtain a nanoimprint molded body having an uneven structure.

  Specifically, the dimensional stability of the three-dimensional molded body formed from the sheet of the present invention is determined by measuring the width or height of the concavo-convex structure formed when the sheet is subjected to nanoimprint molding, and the standard design dimension. The absolute value of the difference can be evaluated from the value divided by the standard design dimension. The value obtained by dividing the absolute value of the difference between the measured value and the design dimension by the reference design dimension is preferably less than 0.05, and more preferably less than 0.02. In addition, the measured value of the width or height of the concavo-convex structure formed when nanoimprint molding is performed on the sheet is performed by depositing platinum on the concavo-convex surface for 10 minutes, and using a field emission scanning electron microscope (JSM Co., Ltd., JSM). -7400F) and observing the surface under an acceleration voltage of 3.00 kV. Usually, the width and height of the concavo-convex structure at 10 or more locations are measured, and the average value is taken as the measured value.

  The three-dimensional molded body molded from the sheet of the present invention is also excellent in mold release properties (mold release properties). The mold releasability (mold releasability) of the three-dimensional molded body molded from the sheet of the present invention is as follows. When nanoimprint molding is carried out 10 times by the method described above, 10 nanoimprint molded bodies are obtained. It can evaluate from the shape of the uneven surface of the nanoimprint molding obtained by the tenth molding. When producing 10 nanoimprint moldings, a mold release agent is sprayed onto the mold only during the first molding. The shape of the concavo-convex surface (the number of convex portions) was obtained by depositing platinum on the concavo-convex surface for 10 minutes and using a field emission scanning electron microscope (manufactured by JEOL Ltd., JSM-7400F) with an acceleration voltage of 3.00 kV. Thus, it can be evaluated by observing the convex shape of the concavo-convex surface at 50 locations, and the quality can be determined from the presence or absence of the defect of the convex shape. In addition, the defect of the shape of a convex part means the state which a part of molded object remains on a metal mold | die, and a molded object has a defect | deletion. In the present invention, the number of defects when evaluated by the above evaluation method is preferably less than 10, and the number of defects is more preferably 0.

  The three-dimensional molded body obtained by molding the sheet of the present invention may be used as a process paper (disposable mold) used to mold another three-dimensional molded body. In this case, the three-dimensional molded body (process paper) goes through a further heat process, but in the present invention, even in such a case, the three-dimensional molded body (process paper) itself has excellent dimensional stability. It can be demonstrated. The dimensional stability of the three-dimensional molded body (process paper) means that an alumina coating solution is applied onto the nanoimprint molded body (process paper) molded from the sheet of the present invention, and dried for 30 minutes with a 120 ° C hot air dryer. Later, it refers to the dimensional stability of the nanoimprint molding (process paper) remaining after peeling the alumina coating layer from the nanoimprint molding. The dimensional stability of the nanoimprint molded body (process paper) can be evaluated in the same manner as the evaluation method and evaluation standard for the dimensional stability of the three-dimensional molded body described above.

  In addition, the three-dimensional molded body (process paper) can also exhibit excellent transferability. Here, the transferability of the three-dimensional molded body (process paper) can be evaluated as the peelability of the alumina coating film after applying alumina on the nanoimprint molded body and drying it. Specifically, an alumina coating solution is applied onto a nanoimprint molded body (process paper) molded from the sheet of the present invention, and dried with a hot air dryer at 120 ° C. for 30 minutes, and then the alumina coated layer is formed into a nanoimprint molded body. The quality of transferability can be determined from the presence or absence of a convex-shaped defect in the uneven pattern of the peeled alumina coating film. The presence or absence of defects in the shape of the convex portions can be evaluated by the same method as the method for evaluating the mold releasability of the three-dimensional molded body described above. In the shape of the concavo-convex pattern of the alumina coating film, the number of defects when evaluated by the above evaluation method is preferably less than 2, and the number of defects is more preferably 0.

  Although the thickness of the sheet | seat of this invention is not specifically limited, It is preferable that it is 5 micrometers or more, It is more preferable that it is 10 micrometers or more, It is further more preferable that it is 20 micrometers or more. Moreover, the upper limit of the thickness of the sheet is not particularly limited, but can be, for example, 1000 μm or less. In addition, the thickness of a sheet | seat can be measured with a stylus type thickness meter (Maltron 1202D by Marl).

The basis weight of the sheet of the present invention is preferably 10 g / m ² or more, more preferably 20 g / m ² or more, and further preferably 30 g / m ² or more. The basis weight of the sheet is preferably 500 g / m ² or less, and more preferably 300 g / m ² or less. Here, the basis weight of the sheet can be calculated in accordance with JIS P 8124.

(Fine fibrous cellulose)
The sheet | seat of this invention contains the fibrous cellulose (fine fibrous cellulose) whose fiber width is 5000 nm or less. The content of the fine fibrous cellulose is preferably 30% by mass or more, more preferably 40% by mass or more, and further preferably 50% by mass or more with respect to the total mass of the sheet. Moreover, it is preferable that content of a fine fibrous cellulose is 90 mass% or less with respect to the total mass of a sheet | seat.

  Although it does not specifically limit as a fibrous cellulose raw material for obtaining a fine fibrous cellulose, It is preferable to use a pulp from the point of being easy to acquire and cheap. Examples of the pulp include wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen bleached craft Chemical pulps such as pulp (OKP) are listed. Moreover, semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP), mechanical pulps such as ground wood pulp (GP), thermomechanical pulp (TMP, BCTMP) and the like can be mentioned, but are not particularly limited. Non-wood pulp includes cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, cellulose isolated from sea squirts and seaweed, chitin, chitosan, etc., but is not particularly limited. . The deinking pulp includes deinking pulp made from waste paper, but is not particularly limited. The pulp of this embodiment may be used alone or in combination of two or more. Among the above pulps, wood pulp containing cellulose and deinked pulp are preferable in terms of availability. Among wood pulps, chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose during fiber refinement (defibration) is high, and the degradation of cellulose in the pulp is small, and the fineness of long fibers with a large axial ratio is high. It is preferable at the point from which fibrous cellulose is obtained. Of these, kraft pulp and sulfite pulp are most preferably selected. When long fibrous fine fibrous cellulose having a large axial ratio is used, a high-strength sheet tends to be obtained.

  The average fiber width of the fine fibrous cellulose is 5000 nm or less as observed with an electron microscope. The average fiber width is preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, more preferably 2 nm or more and 50 nm or less, and further preferably 2 nm or more and 10 nm or less, but is not particularly limited. When the average fiber width of the fine fibrous cellulose is less than 2 nm, the physical properties (strength, rigidity, dimensional stability) as the fine fibrous cellulose tend to be difficult to be expressed because the cellulose molecules are dissolved in water. . The fine fibrous cellulose is, for example, monofilamentous cellulose having a fiber width of 5000 nm or less, and more preferably has a fiber width of 1000 nm or less.

  Measurement of the average fiber width of the fine fibrous cellulose by observation with an electron microscope is performed as follows. An aqueous suspension of fine fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and the suspension is cast on a carbon film-coated grid subjected to a hydrophilic treatment to prepare a sample for TEM observation. To do. When a wide fiber is included, an SEM image of the surface cast on glass may be observed. Observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 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 average fiber width of the fine fibrous cellulose is an average value of the fiber widths read in this way.

  The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and particularly preferably 0.1 μm or more and 600 μm or less. By making the fiber length within the above range, the destruction of the crystalline region of the fine fibrous cellulose can be suppressed, and the slurry viscosity of the fine fibrous cellulose can be made an appropriate range. Note that the fiber length of the fine fibrous cellulose can be determined by image analysis using TEM, SEM, or AFM.

The fine fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fine fibrous cellulose has a type I crystal structure can be identified in a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418Å) monochromatized with graphite. Specifically, it can be identified by having typical peaks at two positions of 2θ = 14 ° to 17 ° and 2θ = 22 ° to 23 °.
The proportion of the I-type crystal structure in the fine fibrous cellulose is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. In this case, further superior performance can be expected in terms of heat resistance and low linear thermal expansion coefficient. The degree of crystallinity is obtained by measuring an X-ray diffraction profile and determining the crystallinity by a conventional method (Seagal et al., Textile Research Journal, 29, 786, 1959).

  The fine fibrous cellulose is preferably one having a substituent, and the substituent is preferably an anionic group. Examples of the anionic group include a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxyl group or a substituent derived from a carboxyl group (sometimes simply referred to as a carboxyl group), In addition, it is preferably at least one selected from a sulfone group or a substituent derived from a sulfone group (sometimes simply referred to as a sulfone group), and at least one selected from a phosphate group and a carboxyl group Is more preferable, and a phosphate group is particularly preferable. That is, the fine fibrous cellulose used in the present invention is preferably phosphorylated cellulose.

The fine fibrous cellulose is preferably one having a phosphate group or a substituent derived from a phosphate group. The phosphoric acid group is a divalent functional group equivalent to the phosphoric acid obtained by removing the hydroxyl group. Specifically, it is a group represented by —PO ₃ H ₂ . Substituents derived from phosphoric acid groups include substituents such as groups obtained by polycondensation of phosphoric acid groups, salts of phosphoric acid groups, and phosphoric acid ester groups. It may be a group.

In the present invention, the phosphate group or the substituent derived from the phosphate group may be a substituent represented by the following formula (1).

In the formula (1), a, b, m and n each independently represent an integer (where a = b × m); α ⁿ (n is an integer from 1 to n) and α ′ are each independently Represents R or OR. R represents 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. , An aromatic group, or a derivative group thereof; β is a monovalent or higher cation composed of an organic substance or an inorganic substance.

<Phosphate group introduction process>
In the phosphate group introduction step, the fiber raw material containing cellulose is reacted with at least one selected from a compound having a phosphate group and a salt thereof (hereinafter referred to as “phosphorylation reagent” or “compound A”). Can be performed. Such a phosphorylating reagent may be mixed in a powder or aqueous solution with a dry or wet fiber raw material. As another example, a phosphorylating reagent powder or an aqueous solution may be added to the fiber raw material slurry.

  The phosphoric acid group introduction step can be performed by reacting at least one selected from a compound having a phosphoric acid group and a salt thereof (a phosphorylating reagent or compound A) with a fiber raw material containing cellulose. This reaction may be carried out in the presence of at least one selected from urea and derivatives thereof (hereinafter referred to as “compound B”).

  As an example of a method for causing compound A to act on a fiber raw material in the presence of compound B, a method of mixing powder or an aqueous solution of compound A and compound B with a dry or wet fiber raw material can be mentioned. Another example is a method in which powders and aqueous solutions of Compound A and Compound B are added to the fiber raw material slurry. Among these, since the uniformity of the reaction is high, a method of adding an aqueous solution of Compound A and Compound B to a dry fiber material, or a powder or an aqueous solution of Compound A and Compound B to a wet fiber material The method is preferred. Moreover, the compound A and the compound B may be added simultaneously, or may be added separately. Moreover, you may add the compound A and the compound B first used for reaction as aqueous solution, and remove an excess chemical | medical solution by pressing. The form of the fiber raw material is preferably cotton or thin sheet, but is not particularly limited.

Compound A used in this embodiment is at least one selected from a compound having a phosphate group and a salt thereof.
Examples of the compound having a phosphate group include, but are not limited to, phosphoric acid, lithium salt of phosphoric acid, sodium salt of phosphoric acid, potassium salt of phosphoric acid, ammonium salt of phosphoric acid, and the like. Examples of the lithium salt of phosphoric acid include lithium dihydrogen phosphate, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, and lithium polyphosphate. Examples of the sodium salt of phosphoric acid include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, and sodium polyphosphate. Examples of the potassium salt of phosphoric acid include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate. Examples of the ammonium salt of phosphoric acid include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate.

  Among these, phosphoric acid and phosphoric acid are introduced efficiently from the viewpoint that the introduction efficiency of phosphate groups is high, the fibrillation efficiency is easily improved in the fibrillation process described later, the cost is low, and the industrial application is easy. Sodium salt, potassium salt of phosphoric acid, and ammonium salt of phosphoric acid are preferable. Sodium dihydrogen phosphate or disodium hydrogen phosphate is more preferable.

  In addition, compound A is preferably used as an aqueous solution because the uniformity of the reaction is increased and the efficiency of introduction of phosphate groups is increased. The pH of the aqueous solution of Compound A is not particularly limited, but is preferably 7 or less because the efficiency of introduction of phosphate groups is increased, and more preferably pH 3 or more and pH 7 or less from the viewpoint of suppressing the hydrolysis of pulp fibers. The pH of the aqueous solution of Compound A may be adjusted by, for example, using a phosphoric acid group-containing compound that exhibits acidity and an alkalinity, and changing the amount ratio thereof. You may adjust pH of the aqueous solution of the compound A by adding an inorganic alkali or an organic alkali to the thing which shows acidity among the compounds which have a phosphoric acid group.

  The amount of compound A added to the fiber raw material is not particularly limited, but when the amount of compound A added is converted to phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5 mass% to 100 mass%. Or less, more preferably 1% by mass or more and 50% by mass or less, and most preferably 2% by mass or more and 30% by mass or less. If the amount of phosphorus atoms added to the fiber raw material is within the above range, the yield of fine fibrous cellulose can be further improved. By making the amount of phosphorus atoms added to the fiber raw material 100% by mass or less, it is possible to balance the effect of improving the yield and the cost. On the other hand, a yield can be raised by making the addition amount of the phosphorus atom with respect to a cellulose fiber more than the said lower limit.

  Examples of the compound B used in this embodiment include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.

  Compound B is preferably used as an aqueous solution in the same manner as Compound A. Moreover, since the uniformity of reaction increases, it is preferable to use the aqueous solution in which both compound A and compound B are dissolved. The amount of Compound B added to the fiber raw material (absolute dry mass) is preferably 1% by mass or more and 500% by mass or less, more preferably 10% by mass or more and 400% by mass or less, and 100% by mass or more and 350% by mass or less. More preferably, it is more preferably 150% by mass or more and 300% by mass or less.

  In addition to Compound A and Compound B, amides or amines may be included in the reaction system. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine, and the like. Among these, triethylamine is known to work as a good reaction catalyst.

  In the phosphoric acid group introduction step, it is preferable to perform a heat treatment. As the heat treatment temperature, it is preferable to select a temperature at which a phosphate group can be efficiently introduced while suppressing thermal decomposition and hydrolysis reaction of the fiber. Specifically, it is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. Moreover, you may use a vacuum dryer, an infrared heating apparatus, and a microwave heating apparatus for a heating.

  During the heat treatment, while water is contained in the fiber raw material slurry to which compound A is added, if the time for allowing the fiber raw material to stand still becomes long, the compound A dissolved with water molecules moves to the fiber raw material surface with drying. To do. Therefore, the concentration of the compound A in the fiber raw material may be uneven, and the introduction of phosphate groups on the fiber surface may not proceed uniformly. In order to suppress the occurrence of unevenness in concentration of Compound A in the fiber material due to drying, a very thin sheet-like fiber material is used, or the fiber material and Compound A are kneaded or stirred with a kneader or the like and dried by heating or reduced pressure. The method should be taken.

  The heating device used for the heat treatment is preferably a device that can always discharge the moisture retained by the slurry and the moisture generated by the addition reaction of the fibers such as phosphate groups to the hydroxyl group of the fiber, such as a blower oven. Etc. are preferred. If water in the system is always discharged, the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the esterification, can be suppressed, and the acid hydrolysis of the sugar chain in the fiber can also be suppressed. A fine fiber having a high axial ratio can be obtained.

  The heat treatment time is also affected by the heating temperature, but it is preferably 1 second or more and 300 minutes or less, preferably 1 second or more and 1000 seconds or less after moisture is substantially removed from the fiber raw material slurry. Preferably, it is 10 seconds or more and 800 seconds or less. In the present invention, the amount of phosphate groups introduced can be within a preferred range by setting the heating temperature and the heating time to appropriate ranges.

  The phosphate group introduction step may be performed at least once, but may be repeated a plurality of times. In this case, more phosphoric acid groups are introduced, which is preferable. In the present invention, for example, it is also a preferred embodiment to perform the phosphate group introduction step twice.

  The amount of phosphate group introduced is preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g or more per 1 g (mass) of fine fibrous cellulose. More preferably, it is particularly preferably 1.00 mmol / g or more. The amount of phosphate groups introduced is preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less, and 3.00 mmol / g or less per 1 g (mass) of fine fibrous cellulose. More preferably. By making the introduction amount of the phosphoric acid group within the above range, the fiber raw material can be easily refined, and the stability of the fine fibrous cellulose can be enhanced. Moreover, by setting the introduction amount of phosphate groups within the above range, good characteristics can be exhibited as a thickener for battery separator coating liquid. In addition, in this specification, content of the phosphoric acid group which a fine fibrous cellulose has (introduction amount of a phosphoric acid group) is equal to the strongly acidic group amount of the phosphoric acid group which a fine fibrous cellulose has so that it may mention later.

  The amount of phosphate group introduced into the fiber material can be measured by a conductivity titration method. Specifically, by performing the defibration process step, after treating the resulting fine fibrous cellulose-containing slurry with an ion exchange resin, by determining the change in electrical conductivity while adding an aqueous sodium hydroxide solution, The amount introduced can be measured.

  In conductivity titration, when alkali is added, the curve shown in FIG. 1 is given. Initially, the electrical conductivity rapidly decreases (hereinafter referred to as “first region”). Thereafter, the conductivity starts to increase slightly (hereinafter referred to as “second region”). Thereafter, the conductivity increment increases (hereinafter referred to as “third region”). That is, three areas appear. The boundary point between the second region and the third region is defined as a point at which the amount of change in conductivity twice, that is, the increase (inclination) in conductivity is maximized. Among these, the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration, and the amount of alkali required in the second region is the amount of weakly acidic groups in the slurry used for titration. Will be equal. When the phosphoric acid group undergoes condensation, apparently weakly acidic groups are lost, and the amount of alkali required in the second region is reduced compared to the amount of alkali required in the first region. On the other hand, the amount of strongly acidic groups coincides with the amount of phosphorus atoms regardless of the presence or absence of condensation, so that the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituent introduced (or the amount of substituents) is simply When said, it represents the amount of strongly acidic group. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 is divided by the solid content (g) in the titration target slurry to obtain the substituent introduction amount (mmol / g).

<Carboxyl group introduction step>
When the fine fibrous cellulose has a carboxyl group, the carboxyl group can be introduced into the fine fibrous cellulose through a carboxyl group introduction step. In the carboxyl group introduction step, the fiber raw material is treated with an oxidation treatment such as a TEMPO oxidation treatment or a compound having a group derived from a carboxylic acid, a derivative thereof, or an acid anhydride or a derivative thereof, whereby a carboxyl group is added to the fine fibrous cellulose. Can be introduced.

  The compound having a carboxyl group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. .

  The acid anhydride of the compound having a carboxyl group is not particularly limited, but examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. It is done.

  Although it does not specifically limit as a derivative of the compound which has a carboxyl group, The derivative of the acid anhydride of the compound which has a carboxyl group and the acid anhydride imidation of a compound which has a carboxyl group are mentioned. Although it does not specifically limit as an acid anhydride imidation thing of a compound which has a carboxyl group, Imidation thing of dicarboxylic acid compounds, such as maleimide, succinic acid imide, and phthalic acid imide, is mentioned.

  The acid anhydride derivative of the compound having a carboxyl group is not particularly limited. For example, at least some of the hydrogen atoms of the acid anhydride of the compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc. are substituted (for example, alkyl group, phenyl group, etc. ) Are substituted.

  In the carboxyl group introduction step, when the TEMPO oxidation treatment is performed, it is also preferable to perform the treatment under conditions where the pH is 6 or more and 8 or less. Such a treatment process is also called neutral TEMPO oxidation treatment. Neutral TEMPO oxidation treatment includes, for example, sodium phosphate buffer (pH = 6.8), nitroxy such as pulp and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) as a catalyst. This can be done by adding sodium hypochlorite as a radical or sacrificial reagent. Furthermore, by allowing sodium chlorite to coexist, an aldehyde generated during the oxidation process can be efficiently oxidized to a carboxyl group.

  The amount of carboxyl groups introduced is preferably 0.10 mmol / g or more, more preferably 0.20 mmol / g or more, and 0.50 mmol / g or more per 1 g (mass) of fine fibrous cellulose. Is more preferable, and particularly preferably 1.00 mmol / g or more. The amount of carboxyl group introduced is preferably 3.65 mmol / g or less, more preferably 3.50 mmol / g or less, and further preferably 3.00 mmol / g or less.

  The amount of carboxyl group introduced can be measured by a conductivity titration method. In the measurement by the conductivity titration method, the introduction amount is measured by obtaining a change in conductivity while adding an aqueous sodium hydroxide solution to the obtained fine fibrous cellulose-containing slurry.

  In the conductivity titration method, the curve shown in FIG. 2 is given when alkali is added. This curve is divided into a first region until the conductivity increment (slope) becomes substantially constant after the electrical conductivity decreases, and then a second region where the conductivity increment (slope) increases. Note that the boundary point between the first region and the second region is defined as the point at which the amount of change in conductivity twice, that is, the increase (inclination) in conductivity is maximized. The alkali amount (mmol) required in the first region of the curve shown in FIG. 2 is divided by the solid content (g) in the fine fibrous cellulose-containing slurry to be titrated, and the amount of carboxyl group introduced (mmol / g).

<Alkali treatment>
When manufacturing a fine fibrous cellulose, you may perform an alkali treatment between substituent introduction processes, such as a phosphate group introduction process and a carboxyl group introduction process, and the fibrillation process mentioned later. Although it does not specifically limit as a method of an alkali treatment, For example, the method of immersing an ionic substituent introduction | transduction fiber in an alkaline solution is mentioned.
The alkali compound contained in the alkali solution is not particularly limited, but may be an inorganic alkali compound or an organic alkali compound. The solvent in the alkaline solution may be either water or an organic solvent. The solvent 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, a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution is particularly preferred because of its high versatility.

Although the temperature of the alkali solution in an alkali treatment process is not specifically limited, 5 to 80 degreeC is preferable and 10 to 60 degreeC is more preferable.
The immersion time in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or longer and 30 minutes or shorter, and more preferably 10 minutes or longer and 20 minutes or shorter.
Although the usage-amount of the alkali solution in an alkali treatment is not specifically limited, It is preferable that it is 100 mass% or more and 100,000 mass% or less with respect to the absolute dry mass of an ionic substituent introduction | transduction fiber, and is 1000 mass% or more and 10,000 mass% or less More preferably.

  In order to reduce the amount of the alkaline solution used in the alkali treatment step, the ionic substituent-introduced fiber 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 ionic substituent-introduced fiber with water or an organic solvent before the defibrating treatment step.

<Defibration processing>
The ionic substituent-introduced fiber is defibrated in the defibrating process. In the defibrating process, the fiber is usually defibrated using a defibrating apparatus to obtain a fine fibrous cellulose-containing slurry, but the processing apparatus and the processing method are not particularly limited.
As the defibrating apparatus, a high-speed defibrator, a grinder (stone mill type pulverizer), a high-pressure homogenizer, an ultra-high pressure homogenizer, a high-pressure collision type pulverizer, a ball mill, a bead mill, or the like can be used. Alternatively, as a defibrating apparatus, a device for wet grinding such as a disk type refiner, a conical refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, or a beater should be used. You can also. The defibrating apparatus is not limited to the above. Preferable defibrating treatment methods include a high-speed defibrator, a high-pressure homogenizer, and an ultra-high pressure homogenizer that are less affected by the grinding media and less worried about contamination.

  In the defibrating treatment, it is preferable to dilute the fiber raw material with water and an organic solvent alone or in combination to form a slurry, but there is no particular limitation. As the dispersion medium, in addition to water, a polar organic solvent can be used. Preferable polar organic solvents include alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like, but are not particularly limited. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol. Examples of ketones include acetone and methyl ethyl ketone (MEK). Examples of ethers include diethyl ether and tetrahydrofuran (THF). The dispersion medium may be one type or two or more types. Further, the dispersion medium may contain a solid content other than the fiber raw material, such as urea having hydrogen bonding property.

  In the present invention, the fibrillation treatment may be performed after the fine fibrous cellulose is concentrated and dried. In this case, the concentration and drying methods are not particularly limited, and examples thereof include a method of adding a concentrating agent to a slurry containing fine fibrous cellulose, a generally used dehydrator, a press, and a method using a dryer. Moreover, a well-known method, for example, the method described in WO2014 / 024876, WO2012 / 107642, and WO2013 / 121086 can be used. Further, the concentrated fine fibrous cellulose may be formed into a sheet. The sheet can be pulverized to perform a defibrating process.

  The equipment used for pulverization of fine fibrous cellulose includes high-speed fibrillators, grinders (stone mill type pulverizers), high-pressure homogenizers, ultra-high pressure homogenizers, high-pressure collision type pulverizers, ball mills, bead mills, disk type refiners, and conicals. An apparatus for wet pulverization such as a refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, a beater, and the like can be used, but is not particularly limited. The treatment conditions are not particularly limited as long as a preferable degree of polymerization is obtained.

(Fluorine-containing compound / siloxane bond-containing compound)
The sheet of the present invention contains at least one selected from a fluorine-containing compound and a siloxane bond-containing compound. The sheet of the present invention may contain any one selected from a fluorine-containing compound and a siloxane bond-containing compound, or may contain both a fluorine-containing compound and a siloxane bond-containing compound. In addition, since a fluorine-containing compound and a siloxane bond-containing compound can exhibit water repellency, these compounds can be collectively referred to as a water-repellent compound.

<Fluorine-containing compound>
A fluorine-containing compound is a compound having at least one fluorine atom in one compound. The fluorine-containing compound is preferably one having two or more fluorine atoms in one compound.

  The fluorine-containing compound is preferably a fluorine-containing compound containing at least one selected from a fluoroalkyl group, a fluorooxyalkyl group, a fluoroalkenyl group, a fluoroalkanediyl group, and a fluorooxyalkanediyl group. Among these, the fluorine-containing compound is preferably a compound containing a fluoroalkyl group. The fluoroalkyl group preferably has 4 to 12 carbon atoms, more preferably 4 to 10 carbon atoms, and still more preferably 6 to 8 carbon atoms. By setting the carbon number of the fluoroalkyl group within the above range, solubility in a solvent can be enhanced while suppressing a decrease in the surface energy of the fluorine-containing compound.

  Here, a fluoroalkyl group, a fluorooxyalkyl group, a fluoroalkenyl group, a fluoroalkanediyl group, and a fluorooxyalkanediyl group are alkyl groups, oxyalkyl groups, alkenyl groups, alkanediyl groups, and oxyalkanediyl groups. Some or all of them are substituted with fluorine. Any group is a substituent mainly composed of a fluorine atom and a carbon atom, and the structure may have a branch. A plurality of the above groups may be linked.

  Moreover, said fluorine-containing compound may have a reactive site. The reactive site refers to a site that reacts with other components by external energy such as heat or light. Examples of such reactive sites include alkoxysilyl groups, silyl ether groups, silanol groups in which alkoxysilyl groups are hydrolyzed, carboxyl groups, hydroxyl groups, epoxy groups, vinyl groups, allyl groups, acryloyl groups, methacryloyl groups, and the like. It is done. Among them, the reactive site is preferably an alkoxysilyl group, a silyl ether group, a silanol group, an epoxy group, a vinyl group, an allyl group, an acryloyl group, or a methacryloyl group from the viewpoint of reactivity and handling properties, and a vinyl group, an allyl group, An acryloyl group and a methacryloyl group are more preferable, and an acryloyl group and a methacryloyl group are particularly preferable.

  The fluorine-containing compound is preferably in the form of a fluorine-containing monomer, a fluorine-containing silane coupling agent, a fluorine-containing surfactant, a fluorine-containing resin, or the like. Among these, the fluorine-containing compound is preferably a fluorine-containing resin, and the fluorine-containing resin may be either amorphous or crystalline. Fluorine-containing resins include tetrafluoroethylene (TFE), tetrafluoroethylene-perfluoroalkyl vinyl ether (FA), tetrafluoroethylene-hexafluoropropylene (FEP), tetrafluoroethylene-ethylene (ETFE), vinylidene fluoride (VDF). ), Chlorotrifluoroethylene (CTFE), or a polymer or copolymer having a unit represented by the following general formula (1) as a structural unit.

  Among these, the fluorine-containing compound is preferably an aqueous emulsion of a fluorine-containing resin or an aqueous dispersion of a fluorine-containing resin, and more preferably an aqueous emulsion from the viewpoint of affinity with a fine fibrous cellulose-containing slurry. Examples of commercially available aqueous emulsions or aqueous dispersions of fluorine-containing resins include AG-E500D (AGC Corporation), AG-E080 (AGC Corporation), MRW-6833-AL (AGC Seikagaku Corporation), D-210C (Daikin Chemical Co., Ltd.) can be mentioned, and these products can be used.

<Siloxane bond-containing compound>
A siloxane bond-containing compound is a compound containing at least one siloxane bond in one compound. The siloxane bond-containing compound is preferably one having two or more siloxane bonds in one compound. The siloxane bond-containing compound is preferably an organosilicon compound containing a siloxane bond.

  The siloxane bond-containing compound is preferably in the form of a modified silicone oil, a silicone-based silane coupling agent, a silicone resin, or the like, and the siloxane bond-containing compound is more preferably a silicone resin.

  Modified silicone oil is classified into straight silicone oil and modified silicone oil. Examples of the straight silicone oil include dimethyl silicone oil, methylphenyl silicone oil, chill hydrogen silicone oil, and the like. For example, dimethyl silicone oil (KF-96) manufactured by Shin-Etsu Silicone Co., Ltd. can be used. The modified silicone oil is a part of the organopolysiloxane substituted with various organic groups. As the organic group, amino group, epoxy group, carboxyl group, carbinol group, methacryl group, mercapto group, phenol group, Examples include polyether groups, methylstyryl groups, alkyl groups, higher fatty acid ester-modified groups, hydrophilic special-modified groups, higher fatty acid-containing groups, fluorine-modified groups, and the like. For example, modified silicone oil (KF- 3935) can be used.

  The silicone-based silane coupling agent is a silane coupling agent having a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, an isocyanurate group, a ureido group, a mercapto group, an isocyanate group or the like as a functional group. It is preferable. For example, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane (KBM-603) manufactured by Shin-Etsu Silicone Co., Ltd. can be used.

Silicone resins are high molecular resins composed of a three-dimensional siloxane network structure, and are classified into straight silicone resins and modified silicone resins. Examples of the straight silicone resin include methyl silicone resin and methylphenyl silicone resin. Examples of the modified silicone resin include alkyd-modified silicone resin, epoxy-modified silicone resin, acrylic-modified silicone resin, and polyester-modified silicone resin.
Among these, the siloxane bond-containing compound is preferably an aqueous emulsion of a silicone resin and an aqueous dispersion of a silicone resin, and more preferably an aqueous emulsion from the viewpoint of affinity with a fine fibrous cellulose-containing slurry. Examples of commercially available silicone resin aqueous emulsions or aqueous dispersions include KM-740T (Shin-Etsu Silicone), POLON MF-14 (Shin-Etsu Silicone), SM8706EX (Toray Dow Corning). Can use these products.

<Content of fluorine-containing compound / siloxane bond-containing compound>
The content of at least one selected from a fluorine-containing compound and a siloxane bond-containing compound is preferably 5% by mass or more, more preferably 10% by mass or more, based on the total mass of the sheet. More preferably, it is at least mass%. The content of at least one selected from a fluorine-containing compound and a siloxane bond-containing compound is preferably 70% by mass or less and more preferably 60% by mass or less with respect to the total mass of the sheet. .
In addition, it is preferable that content of at least 1 sort (s) selected from a fluorine-containing compound and a siloxane bond containing compound is 5 mass parts or more with respect to 100 mass parts of fine fibrous cellulose, and is 10 mass parts or more. Is more preferable, and more preferably 15 parts by mass or more. Moreover, it is preferable that content of at least 1 sort (s) selected from a fluorine-containing compound and a siloxane bond containing compound is 70 mass parts or less with respect to 100 mass parts of fine fibrous cellulose, and is 50 mass parts or less. Is more preferable.
By making the content of at least one selected from a fluorine-containing compound and a siloxane bond-containing compound within the above range, the dimensional stability and transferability (releasability) of a three-dimensional molded article molded from a sheet are effective. Can be enhanced.

  The content of at least one selected from the fluorine-containing compound and the siloxane bond-containing compound in the sheet can be analyzed using, for example, NMR measurement, MS fragment analysis, UV analysis, or the like.

(Hydrophilic resin)
The sheet | seat of this invention contains hydrophilic resin. The hydrophilic resin can improve the strength, density and chemical resistance of the sheet. The hydrophilic resin preferably has, for example, an SP value of 9.0 or more. Further, the hydrophilic resin is preferably one in which 1 g or more of the hydrophilic resin is dissolved in, for example, 100 ml of ion exchange water.

  Examples of hydrophilic resins include polyethylene glycol, cellulose derivatives (such as hydroxyethyl cellulose, carboxyethyl cellulose, and carboxymethyl cellulose), casein, dextrin, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol (such as acetoacetylated polyvinyl alcohol), and polyethylene. Examples thereof include oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylic acid salts, polyacrylamide, alkyl acrylate copolymer, and urethane copolymer. Among these, the hydrophilic resin is preferably at least one selected from polyethylene glycol (PEG), polyvinyl alcohol (PVA), modified polyvinyl alcohol (modified PVA), and polyethylene oxide (PEO).

  The molecular weight of the hydrophilic resin is preferably 50,000 or more and 8 million or less, and more preferably 100,000 or more and 5 million or less.

The content of the hydrophilic resin is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 12% by mass or more with respect to the total mass of the sheet. Moreover, it is preferable that it is 70 mass% or less with respect to the total mass of a sheet | seat, and, as for content of hydrophilic resin, it is more preferable that it is 60 mass% or less.
The content of the hydrophilic resin is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and more preferably 15 parts by mass or more with respect to 100 parts by mass of the fine fibrous cellulose. Further preferred. Moreover, it is preferable that it is 70 mass parts or less with respect to 100 mass parts of fine fibrous cellulose, and, as for content of hydrophilic resin, it is more preferable that it is 50 mass parts or less.
By setting the content of the hydrophilic resin within the above range, the strength, density, chemical resistance and the like of the sheet can be further improved.

(Optional component)
The sheet of the present invention may contain an optional component other than the components described above. Examples of optional components include antifoaming agents, lubricants, ultraviolet absorbers, dyes, pigments, stabilizers, and surfactants.

  Moreover, the sheet | seat of this invention may contain the organic ion as an arbitrary component. Examples of organic ions include tetraalkylammonium ions and tetraalkylphosphonium ions. Examples of tetraalkylammonium ions include tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, tetraheptylammonium ion, tributylmethylammonium ion, and lauryltrimethyl. Examples include ammonium ion, cetyltrimethylammonium ion, stearyltrimethylammonium ion, octyldimethylethylammonium ion, lauryldimethylethylammonium ion, didecyldimethylammonium ion, lauryldimethylbenzylammonium ion, and tributylbenzylammonium ion. Examples of tetraalkylphosphonium ions include tetramethylphosphonium ions, tetraethylphosphonium ions, tetrapropylphosphonium ions, tetrabutylphosphonium ions, and lauryltrimethylphosphonium ions. In addition, examples of the tetrapropylonium ion and the tetrabutylonium ion include a tetra n-propylonium ion and a tetra n-butylonium ion, respectively.

  In addition to the hydrophilic resin, a thermoplastic resin emulsion, a thermosetting resin emulsion, a photocurable resin emulsion, or the like may be added to the sheet of the present invention. Specific examples of the thermoplastic resin emulsion, the thermosetting resin emulsion, and the photocurable resin emulsion include those described in JP2009-299043A.

(Sheet manufacturing method)
The manufacturing process of the sheet includes a step of obtaining a slurry containing fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin. It includes a step of coating on a substrate or a step of making a paper from a slurry. Among them, the sheet manufacturing process includes a slurry containing fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin (hereinafter simply referred to as slurry). It may be preferable to include a step of coating the base material on the substrate.

<Coating process>
In the coating process, a slurry containing fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin is coated on a substrate. This is a step of obtaining a sheet by peeling the sheet formed by drying it from the substrate. By using a coating apparatus and a long base material, sheets can be continuously produced.

  The material of the base material used in the coating process is not particularly limited, but the one with higher wettability to the slurry may be able to suppress the shrinkage of the sheet during drying, but the sheet formed after drying is easier. It is preferable to select one that can be peeled. Among them, a resin plate or a metal plate is preferable, but not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, metal plates such as aluminum plates, zinc plates, copper plates, iron plates, etc., and their surfaces oxidized, stainless steel A plate, a brass plate or the like can be used.

  In the coating process, when the slurry has a low viscosity and spreads on the base material, a damming frame may be fixed on the base material to obtain a sheet having a predetermined thickness and basis weight. Good. The quality of the damming frame is not particularly limited, but it is preferable to select one that can easily peel off the edge of the sheet attached after drying. Among them, a molded resin plate or metal plate is preferable, but is not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, metal plates such as aluminum plates, zinc plates, copper plates, iron plates, etc., and their surfaces oxidized, stainless steel A plate, a brass plate or the like can be used.

  As a coating machine for applying the slurry, for example, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater or the like can be used. A die coater, a curtain coater, and a spray coater are preferable because the thickness can be made more uniform.

  The coating temperature is not particularly limited, but is preferably 20 ° C or higher and 45 ° C or lower, more preferably 25 ° C or higher and 40 ° C or lower, and further preferably 27 ° C or higher and 35 ° C or lower. If the coating temperature is not less than the above lower limit value, the slurry can be easily applied, and if it is not more than the above upper limit value, volatilization of the dispersion medium during coating can be suppressed.

In the coating step, it is preferable to apply the slurry so that the finished basis weight of the sheet is 10 g / m ² or more and 500 g / m ² or less, preferably 20 g / m ² or more and 300 g / m ² or less. By coating so that the basis weight is within the above range, a sheet having excellent strength can be obtained.

  It is preferable that a coating process includes the process of drying the slurry apply | coated on the base material. Although it does not specifically limit as a drying method, Either a non-contact drying method or the method of drying while restraining a sheet | seat may be sufficient, and these may be combined.

  The non-contact drying method is not particularly limited, but a method of drying by heating with hot air, infrared rays, far infrared rays or near infrared rays (heating drying method) or a method of drying in vacuum (vacuum drying method) is applied. Can do. Although the heat drying method and the vacuum drying method may be combined, the heat drying method is usually applied. Although drying by infrared rays, far infrared rays, or near infrared rays can be performed using an infrared device, a far infrared device, or a near infrared device, it is not particularly limited. The heating temperature in the heat drying method is not particularly limited, but is preferably 20 ° C. or higher and 150 ° C. or lower, and more preferably 25 ° C. or higher and 105 ° C. or lower. If the heating temperature is not less than the above lower limit value, the dispersion medium can be volatilized quickly, and if it is not more than the above upper limit value, it is possible to suppress the cost required for heating and to prevent the fine fibrous cellulose from being discolored by heat. .

<Paper making process>
The manufacturing process of the sheet may include a step of papermaking a slurry containing fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin. . Examples of the paper machine in the paper making process include a continuous paper machine such as a long-mesh type, a circular net type, and an inclined type, and a multi-layered paper machine combining these. In the paper making process, known paper making such as hand making may be performed.

  In the papermaking process, the slurry is filtered and dehydrated on a wire to obtain a wet paper sheet, and then the sheet is obtained by pressing and drying. When the slurry is filtered and dehydrated, the filter cloth at the time of filtration is not particularly limited, but it is important that fine fibrous cellulose and other components do not pass through and the filtration rate is not too slow. Although it does not specifically limit as such a filter cloth, The sheet | seat, fabric, and porous film which consist of organic polymers are preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and the like are preferable. Specific examples include a porous film of polytetrafluoroethylene having a pore size of 0.1 μm to 20 μm, for example, 1 μm, polyethylene terephthalate or polyethylene woven fabric having a pore size of 0.1 μm to 20 μm, for example, 1 μm, but is not particularly limited.

  Although it does not specifically limit as a method of manufacturing a sheet | seat from a slurry, For example, the method of using the manufacturing apparatus of WO2011 / 013567, etc. are mentioned. This manufacturing apparatus discharges a slurry containing fine fibrous cellulose onto the upper surface of an endless belt, squeezes a dispersion medium from the discharged slurry, generates a web, and dries the web to dry the fiber sheet. And a drying section to produce. An endless belt is disposed from the squeezing section to the drying section, and the web generated in the squeezing section is conveyed to the drying section while being placed on the endless belt.

  The dehydration method that can be employed is not particularly limited, and examples thereof include a dehydration method that is usually used in paper production. A method of dehydrating with a long net, a circular net, an inclined wire, etc., and then dehydrating with a roll press is preferable. The drying method is not particularly limited, and examples thereof include methods used in paper production. For example, methods such as a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, and an infrared heater are preferable.

(Laminated sheet)
The present invention also relates to a laminated sheet further having a resin layer on at least one surface side of the above-described sheet. The resin layer is preferably laminated directly on at least one surface of the above-described sheet.

  The resin layer is preferably a layer containing at least one selected from a fluororesin, a silicone resin, an acrylic resin, a polycarbonate resin, a urethane resin, a polyethylene resin, and a polyvinyl alcohol resin. Among them, the resin layer is more preferably a layer containing at least one selected from a fluororesin, a silicone resin and a polycarbonate resin, and is a layer containing at least one selected from a fluororesin and a silicone resin. Further preferred.

  The thickness of the resin layer is not particularly limited, but is preferably 0.05 μm or more, more preferably 0.1 μm or more, and further preferably 0.2 μm or more. Moreover, the upper limit value of the thickness of the resin layer is not particularly limited, but can be, for example, 10 μm or less. The thickness of the resin layer is a value measured by cutting a cross section of the laminated sheet with an ultramicrotome UC-7 (manufactured by JEOL) and observing the cross section with an electron microscope.

  The resin layer is preferably a layer formed by coating, and the resin layer formed by coating may be referred to as a coating layer or a coating film. In this case, in the step of forming the resin layer, the resin layer forming composition is applied to at least one surface of the sheet. Examples of the coating machine that can be used in the coating process include a bar coater, a roll coater, a gravure coater, a die coater, a curtain coater, and an air doctor coater.

  It is preferable to provide a curing step after application of the resin layer forming composition. As the curing step, it is more preferable to provide a thermosetting step. In the thermosetting step, for example, it is preferable to heat at 25 ° C. or higher and 300 ° C. or lower for 10 seconds or longer and 10 hours or shorter. In the thermosetting step, for example, a method of heating and drying with hot air, infrared rays, far infrared rays or near infrared rays (heating drying method), a method of drying in a vacuum (vacuum drying method) can be applied. Moreover, in order to accelerate hardening more, it is more preferable to cure at room temperature for about 1 day to 1 week.

In the curing step, a photocuring step may be employed, and the thermosetting step and the photocuring step may be performed simultaneously. In this case, a light curing process, a 450nm UV light below or 300 nm, it is preferable to irradiate with 10 mJ / cm ² or more 8000 mJ / cm ² or less.

(Three-dimensional molded body)
The present invention also relates to the above-described sheet or a three-dimensional molded body of the above-described laminated sheet. The three-dimensional molded body is preferably a nanoimprint molded body capable of forming a fine concavo-convex structure, and more preferably a thermal nanoimprint molded body. Further, the above-described sheet or the above-described three-dimensional molded body of the laminated sheet may be used as a process paper (disposable mold) used for molding another three-dimensional molded body.

  The thermal nanoimprint molded body can be obtained by pressing a mold having a fine concavo-convex structure on the above-described sheet or the above-described laminated sheet, followed by heating and pressing. As the mold, for example, a mold for nanoimprint (model number: MTLS1 / 2 / 2-50 × 50), a line and space type, made of silicon, specifications (width: 1 μm, height: 2 μm, pitch: 2 μm), molding area: 50 mm × 50 mm, mold area 50 mm × 50 mm. As the release spray, an aerosol type spray (model number: MRF-6758-AL) manufactured by AGC Sey Chemical Co., Ltd. can be used. Moreover, it is preferable that the pressurization conditions at the time of heat press molding are 0.1 MPa or more and 10 MPa or less, the heat conditions are preferably 100 ° C. or more and 300 ° C. or less, and the heat press molding time is 10 seconds. It is preferable that it is 100 minutes or less.

  The three-dimensional molded body thus produced has both high dimensional stability and transferability (release property). In addition, transferability (releasing properties) includes the releasability from the mold used when molding the three-dimensional molded body and the other three-dimensional molded body when used as process paper (disposable mold). Includes peelability.

  The sheet or laminated sheet of the present invention is also suitable for use as a three-dimensional molded sheet obtained by hot press molding, for example, electronic equipment boards, fixed telephone members, various vehicles and building window materials, It is also used for applications such as interior materials, exterior materials, and packaging materials.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
<Production of phosphate group-introduced cellulose fiber>
100 parts by mass (absolute dry mass) of softwood kraft pulp is impregnated with a mixed aqueous solution of ammonium dihydrogen phosphate and urea, and compressed to 49 parts by mass of ammonium dihydrogen phosphate and 130 parts by mass of urea. Got. The obtained chemical solution-impregnated pulp was dried with a dryer at 105 ° C. to evaporate the moisture and pre-dried. Then, it heated for 10 minutes with the ventilation dryer set to 140 degreeC, the phosphate group was introduce | transduced into the cellulose in a pulp, and the phosphorylated pulp was obtained.

  The obtained phosphorylated pulp was fractionated by 100 g, and 10 L of ion-exchanged water was poured, stirred and dispersed uniformly, and then subjected to filtration and dehydration to obtain a dehydrated sheet, which was repeated twice. Next, the obtained dehydrated sheet was diluted with 10 L of ion-exchanged water, and a 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 or more and 13 or less. Thereafter, the pulp slurry was dehydrated to obtain a dehydrated sheet, and then 10 L of ion exchange water was added. The step of stirring and dispersing uniformly, followed by filtration and dehydration to obtain a dehydrated sheet was repeated twice.

In the same manner as described above, the step of introducing phosphate groups and the step of filtration and dehydration were repeated on the obtained dehydrated sheet to obtain a twice-phosphorylated cellulose dehydrated sheet. The infrared absorption spectrum of the obtained dehydration sheet was measured by FT-IR. As a result, absorption based on phosphate groups was observed at 1230 cm ⁻¹ or more and 1290 cm ⁻¹ or less, and addition of phosphate groups was confirmed.

<Defibration processing>
Ion exchange water was added to the obtained double-phosphorylated cellulose dehydrated sheet to prepare a slurry having a solid content concentration of 2% by mass. This slurry was treated three times at a pressure of 245 MPa with a wet atomization apparatus (manufactured by Sugino Machine, Optimizer) to obtain a fine fibrous cellulose dispersion.

<Measurement of substituent amount>
The amount of substituent introduction is the amount of phosphate groups introduced into the fiber material, and the larger this value, the more phosphate groups are introduced. The amount of substituent introduced was measured by diluting the target fine fibrous cellulose with ion-exchanged water so that the content was 0.2% by mass, and then treating with ion-exchange resin and titration with alkali. In the treatment with an ion exchange resin, 1/10 by volume of a strongly acidic ion exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) is added to the 0.2 mass% fibrous cellulose-containing slurry and shaken for 1 hour. Went. Thereafter, the mixture was poured onto a mesh having an opening of 90 μm to separate the resin and the slurry. In titration using an alkali, a change in the value of electrical conductivity exhibited by the slurry was measured while adding a 0.1N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after ion exchange. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 (phosphate group) is divided by the solid content (g) in the titration target slurry, and the substituent introduction amount (mmol / g). As a result of calculation, it was 0.98 mmol / g.

<Measurement of fiber width>
The fiber width of the fine fibrous cellulose was measured by the following method.
The supernatant of the fine fibrous cellulose dispersion was diluted with water so that the concentration was 0.01% by mass or more and 0.1% by mass or less, 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.). This confirmed that it was a fine fibrous cellulose having a width of about 4 nm.

<Sheet>
Polyethylene oxide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight: 4 million) was added to the fine fibrous cellulose dispersion so as to be 20 parts by mass with respect to 100 parts by mass of the fine fibrous cellulose. Subsequently, a fluorine-containing compound (AGC Corporation, AG-E500D) was added to 20 parts by mass with respect to 100 parts by mass of fine fibrous cellulose. Thereafter, the concentration was adjusted so that the solid content concentration was 0.6% by mass. The dispersion was weighed so that the finished basis weight of the sheet was 100 g / m ² , applied to a commercially available acrylic plate, and dried with a dryer at 70 ° C. for 24 hours. In addition, the board for damming was arrange | positioned on the acrylic board so that it might become predetermined | prescribed basic weight. The sheet | seat was obtained by the above procedure and the thickness was 65 micrometers.

[Example 2]
A sheet was obtained in the same manner as in Example 1 except that the fluorine-containing compound was changed to a silicone resin (KM-740T, manufactured by Shin-Etsu Silicone Co., Ltd.).

Example 3
After preparing fluororesin (AGC Co., Ltd., AG-E500D, solid content concentration of 30% by mass) with toluene to a solid content concentration of 10% by mass, it was applied on the sheet obtained in Example 1 with a # 2 wire bar. The laminate sheet was obtained by drying with a dryer at 100 ° C. for 10 minutes. At this time, the thickness of the fluororesin resin layer on the sheet was 0.4 μm.

Example 4
A sheet was obtained in the same manner as in Example 1, except that the polyethylene oxide was changed to polyvinyl alcohol (Kuraray Co., Ltd., Poval 5-98). After a fluorine-containing compound (AGC Corporation, AG-E500D, solid content concentration of 30% by mass) was prepared with toluene to a solid content concentration of 10% by mass, it was applied onto the obtained sheet with a # 2 wire bar, and 100 A laminated sheet was obtained by drying for 10 minutes with a dryer at ° C. At this time, the thickness of the resin layer of the fluorine-containing compound on the sheet was 0.4 μm.

Example 5
100 parts by mass of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847T, solid content concentration 30% by mass) and 1 part by mass of platinum-based catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PL-50T, solid content concentration 2% by mass) A solution obtained by diluting the mixed solution of toluene with toluene (solid content concentration: 10% by mass) is applied onto the sheet obtained in Example 1 with a # 2 wire bar and dried by drying at 100 ° C. for 10 minutes. A sheet was obtained. The thickness of the resin layer of the silicone resin on the sheet at this time was 0.4 μm.

Example 6
Example 1 After preparing 100 parts by mass of a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., Iupizeta 2136) and 15 parts by mass of a curing agent (manufactured by Asahi Kasei Chemicals Co., Ltd., TPA-100) to a solid content concentration of 10% by mass, Example 1 The laminated sheet was obtained by coating with a # 2 wire bar on the sheet obtained in step 1 and drying for 10 minutes with a dryer at 100 ° C. The thickness of the resin layer of the polycarbonate resin on the sheet at this time was 0.4 μm.

[Comparative Example 1]
A sheet was obtained in the same manner as in Example 1 except that the fluorine-containing compound was not added.

[Comparative Example 2]
After preparing a fluororesin (AGC Co., Ltd., AG-E500D, solid content concentration of 30% by mass) with toluene to a solid content concentration of 10% by mass, it was coated on the sheet obtained in Comparative Example 1 with a # 2 wire bar. The laminate sheet was obtained by drying with a dryer at 100 ° C. for 10 minutes. At this time, the thickness of the fluororesin resin layer on the sheet was 0.4 μm.

[Comparative Example 3]
After preparing a fluororesin (AGC Corporation, AG-E500D, solid content concentration of 30% by mass) with toluene to a solid content concentration of 10% by mass, on a commercially available polypropylene film (thickness 60 μm), # 2 wire A laminated sheet was obtained by applying with a bar and drying with a dryer at 100 ° C. for 10 minutes. At this time, the thickness of the fluororesin resin layer on the sheet was 0.4 μm.

<Preparation method of nanoimprint molding>
Using the sheets or laminated sheets prepared in Examples and Comparative Examples, nanoimprint molded articles were prepared by the following method.
(1) A mold release spray was applied to the mold. As molds, manufactured by Cyvax, nanoimprint mold (model number: MTLS1 / 2 / 2-50 × 50), line and space type, silicon, specifications (width: 1 μm, height: 2 μm, pitch: 2 μm) Molding area: 50 mm × 50 mm and mold area 50 mm × 50 mm were used. As the mold release spray, an aerosol type spray (model number: MRF-6758-AL) manufactured by AGC Seikagaku Co., Ltd. was used.
(2) Sheets or laminated sheets prepared in Examples and Comparative Examples were cut into 40 mm × 40 mm.
(3) A die and a cut sheet or a laminated sheet were set in a press machine (manufactured by Aida Engineering Co., Ltd., 160 mm square mini test press with a cooler).
(4) After pressing at a pressure of 3 MPa and a temperature of 180 ° C. for 1 minute, the mold was cooled until the temperature of the mold reached 30 ° C.
(5) The sheet was peeled from the mold to obtain a nanoimprint molded body having an uneven structure.

[Evaluation]
Using the sheets or laminated sheets produced in the examples and comparative examples, the dimensional stability and peelability when producing nanoimprint molded articles were evaluated according to the following evaluation methods.

(1) Evaluation of dimensional stability of nanoimprint molded article Platinum was vapor-deposited on the uneven surface of the nanoimprint molded article for 10 minutes, and an accelerating voltage of 3 using a field emission scanning electron microscope (JSM-7400F, manufactured by JEOL Ltd.). The surface was observed under the condition of 0.000 kV, and the width and height were measured. Each measurement was performed at 50 points, and the average value was taken as each measurement value. When the measured values of height and width are different, the larger difference from the reference design dimension was evaluated as the measured value.
A: | (Measured value of width or height)-(Standard design dimension) | / (Standard design dimension) <0.02
○: 0.02 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension) <0.05
Δ: 0.05 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension) <0.10
×: 0.10 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension)

(2) Evaluation of releasability when a sheet is peeled from a mold In <Preparation method of nanoimprint molded article>, after performing (1), the operations of (2) to (5) are repeated 10 times (release spray) Application was performed only once for the first time), and 10 nanoimprint molded bodies were obtained. Platinum was deposited on the concavo-convex surface of the nanoimprint molded body obtained for the 10th time for 10 minutes, and using a field emission scanning electron microscope (JSM-7400F, manufactured by JEOL Ltd.) under the condition of an acceleration voltage of 3.00 kV. The convex shape of the concavo-convex surface was observed at 50 locations, and the peelability was evaluated from the convex shape according to the following criteria. In addition, the case where there exists a defect in a convex part shape means the state in which a part of molded object remains on a metal mold | die, and a molded object has a defect | deletion.
A: All 50 convex portions have no defect and a concavo-convex pattern is formed. O: One or more defective convex portions is less than 10 Δ: Defected convex portions are 10 or more and less than 50 ×: Defects More than 50 convex parts

  The suitability of the process paper when the nanoimprint molded article was used as the process paper (disposable mold) was evaluated according to the following evaluation method.

(3) Transferability evaluation as process paper (evaluation of peelability of alumina coating film after applying alumina on nanoimprint molding and drying)
1000 parts by mass of isopropyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts by mass of alumina (manufactured by Daimei Chemical Co., Ltd., TM-300, primary particle size 7 nm), acrylic (manufactured by DIC, ACRICID 54-172-60) ) After adding 1 part by mass and 1 part by mass of a dispersant (manufactured by San Nopco, SN Dispersant 9228), the mixture was stirred at 1000 rpm for 1 hour using a stirrer to obtain an alumina coating solution. Next, an alumina coating solution is applied onto the nanoimprint molded body with a # 100 wire bar and dried with a hot air dryer at 120 ° C. for 30 minutes, and then the alumina coating layer is peeled off from the nanoimprint molded body to have an uneven structure. A coating film was obtained.
Platinum is deposited on the concavo-convex surface of the alumina coating film for 10 minutes, and using a field emission scanning electron microscope (JSM-7400F, JSM-7400F), the concavo-convex shape of the concavo-convex surface is obtained under an acceleration voltage of 3.00 kV. Were observed at 50 locations, and the transferability was evaluated according to the following criteria from the convex shape.
A: All 50 convex portions have no defect and a concavo-convex pattern is formed. O: One or more defective convex portions is less than two. Δ: Two or more defective convex portions are less than 50. X: Defect. There are 50 or more convex parts with defects

(4) Dimensional stability evaluation as process paper <(3) Transferability evaluation as process paper> The alumina coating film was formed. Platinum was deposited on the uneven surface of the alumina coating film for 10 minutes, and the surface was observed under the condition of an acceleration voltage of 3.00 kV using a field emission scanning electron microscope (JSM-7400F, manufactured by JEOL Ltd.). And the height were measured respectively. Each measurement was performed at 50 points, and the average value was taken as each measurement value. When the measured values of height and width are different, the larger difference from the reference design dimension was evaluated as the measured value.
A: | (Measured value of width or height)-(Standard design dimension) | / (Standard design dimension) <0.02
○: 0.02 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension) <0.05
Δ: 0.05 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension) <0.10
×: 0.10 ≦ | (measured value of width or height) − (reference design dimension) | / (reference design dimension)

  In the examples, the dimensional stability of the nanoimprint molded body after molding was high, and the peelability from the mold was also good. In addition, when the nanoimprint molded body was used as process paper, the transferability of the process paper (alumina coating film peelability) was good, and the dimensional stability of the process paper was maintained high even after transfer. .

Claims (8)

  A sheet comprising fibrous cellulose having a fiber width of 5000 nm or less, at least one selected from a fluorine-containing compound and a siloxane bond-containing compound, and a hydrophilic resin.   The sheet according to claim 1, wherein the content of at least one selected from the fluorine-containing compound and the siloxane bond-containing compound is 5% by mass or more and 70% by mass or less with respect to the total mass of the sheet.   The sheet according to claim 1 or 2, wherein the content of the fibrous cellulose is 30% by mass or more and 90% by mass or less with respect to the total mass of the sheet.   The sheet according to any one of claims 1 to 3, wherein a content of the hydrophilic resin is 5% by mass or more and 70% by mass or less with respect to a total mass of the sheet.   It is a sheet | seat for three-dimensional molded objects, The sheet | seat of any one of Claims 1-4.   The laminated sheet which further has a resin layer in the at least one surface side of the sheet | seat of any one of Claims 1-5.   The said resin layer is a laminated sheet of Claim 6 containing at least 1 sort (s) selected from a fluororesin, a silicone resin, an acrylic resin, a polycarbonate resin, a urethane resin, a polyethylene resin, and a polyvinyl alcohol resin.   The sheet according to any one of claims 1 to 5, or a three-dimensional molded body of the laminated sheet according to claim 6 or 7.

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