JP6531615B2 - Sheet and molded body - Google Patents

Description

  The present invention relates to a sheet and a formed body. Specifically, the present invention relates to a sheet containing fine fibrous cellulose, a thermoplastic resin fiber, and a non-fibrous oxygenated organic compound, and a molded article formed from the sheet.

  BACKGROUND ART In recent years, materials using renewable natural fibers have attracted attention due to substitution of petroleum resources and heightened environmental awareness. Among natural fibers, fibrous cellulose having a fiber diameter of 10 μm to 50 μm, particularly fibrous cellulose derived from wood (pulp) has been widely used mainly as a paper product.

  As fibrous cellulose, fine fibrous cellulose having a fiber diameter of 1 μm or less is also known. In addition, a sheet composed of such fine fibrous cellulose, and a composite sheet containing a fine fibrous cellulose-containing sheet and a resin have been developed (for example, Patent Documents 1 to 5). In sheets and composite sheets containing fine fibrous cellulose, it is known that the tensile strength and the like are greatly improved because the contact points between the fibers are significantly increased. It is also known that the transparency is greatly improved when the fiber width is shorter than the wavelength of visible light.

  Patent documents 1 to 5 disclose composite sheets containing fine fibrous cellulose and a resin. For example, in Patent Documents 1 and 2, a composite sheet is formed by impregnating a fine fibrous cellulose-containing sheet with a thermoplastic resin-containing solution. Patent Literatures 1 and 2 also describe a method of forming a composite sheet by sandwiching a fine fibrous cellulose-containing sheet with a thermoplastic resin sheet as a method of producing a composite sheet. Further, Patent Document 3 discloses a composite sheet including a fine fibrous cellulose-containing sheet and a resin, wherein the fine fibrous cellulose is unevenly distributed on at least one surface. In Patent Document 3, a composite sheet is formed by casting a thermoplastic resin-containing solution on a fine fibrous cellulose-containing sheet.

  Patent Document 4 discloses a composite sheet containing fine fibrous cellulose and a resin emulsion. In Patent Document 4, a composite sheet is formed by forming a thermoplastic resin into a resin emulsion and then mixing it with fine fibrous cellulose. Further, Patent Document 5 discloses a composite sheet formed by mixing fine fibrous cellulose and a thermoplastic resin fiber.

JP, 2015-89914, A JP, 2015-86266, A JP, 2015-17184, A JP, 2015-93882, A JP, 2015-25033, A

  As mentioned above, various composite sheets containing fine fibrous cellulose and a resin have been developed. However, in Patent Documents 1 to 4, the composite sheet is formed by impregnating the fine fibrous cellulose-containing sheet with a solution or an emulsion containing a thermoplastic resin, and thus a molded article excellent in strength can not be obtained. Was a problem. Moreover, when a composite sheet is formed by sandwiching the fine fibrous cellulose-containing sheet with a thermoplastic resin sheet, similarly, there is a problem that a molded article excellent in strength can not be obtained.

  On the other hand, in Patent Document 5, a composite sheet is formed by mixing fine fibrous cellulose and a thermoplastic resin fiber, but a molded article formed from such a composite sheet tends to be inferior in transparency. There was a problem that the use was limited. Moreover, the strength may be insufficient even in the case of a molded body formed from the composite sheet obtained in Patent Document 5, and further improvement has been desired.

  Therefore, in order to solve the problems of the prior art, the inventors of the present invention have a composite sheet (hereinafter, also simply referred to as a sheet) capable of forming a molded article having high transparency and excellent strength. Investigation was advanced for the purpose of providing a forming object formed from a sheet.

As a result of intensive investigations to solve the above problems, the present inventors have a sheet containing fine fibrous cellulose and a thermoplastic resin fiber further contain a non-fibrous oxygenated organic compound, and By making content of an oxygen organic compound into a predetermined | prescribed range, it discovered that the sheet | seat which can shape | mold the molded object excellent in transparency and intensity | strength is obtained.
Specifically, the present invention has the following configuration.

[1] A sheet comprising fine fibrous cellulose having a fiber width of 1000 nm or less, a thermoplastic resin fiber, and a non-fibrous oxygenated organic compound, wherein the content of the oxygenated organic compound is the total mass of the sheet Sheet that is 20% by mass or less.
[2] The sheet according to [1], wherein the oxygen-containing organic compound is a hydrophilic organic compound.
[3] The sheet according to [1] or [2], wherein the oxygen-containing organic compound is an organic compound containing an oxyalkylene structure.
[4] The sheet according to any one of [1] to [3], wherein the oxygen-containing organic compound is an organic compound having a molecular weight of 50,000 to 8,000,000.
[5] The sheet according to any one of [1] to [4], wherein the oxygen-containing organic compound is at least one selected from polyethylene glycol and polyethylene oxide.
[6] The sheet according to any one of [1] to [5], wherein the thermoplastic resin fiber is a fiber containing at least one selected from polylactic acid, ethylene-vinyl alcohol copolymer, polyethylene terephthalate and polypropylene.
[7] The sheet according to any one of [1] to [6], wherein the fine fibrous cellulose has a phosphate group or a substituent derived from a phosphate group.
[8] The sheet according to any one of [1] to [7], wherein the content of the thermoplastic resin fiber is 15% by mass to 45% by mass with respect to the total mass of the sheet.
[9] The sheet according to any one of [1] to [8], wherein the total light transmittance of the molded product heat-pressed under the conditions of melting point + 50 ° C. of thermoplastic resin fiber and 10 MPa is 70% or more.
[10] The sheet according to any one of [1] to [9], which has a haze of 20% or less of a molded product heat-pressed under the conditions of melting point + 50 ° C. of thermoplastic resin fibers and 10 MPa.
[11] Any of [1] to [10] having a flexural modulus of 7 GPa or more at 23 ° C. and a relative humidity of 50% of a molded body heated and pressed under the conditions of melting point + 50 ° C. of thermoplastic resin fibers and 10 MPa. Sheet described in.
[12] A molded article comprising fine fibrous cellulose having a fiber width of 1000 nm or less, a thermoplastic resin, and a non-fibrous oxygenated organic compound, wherein the content of the oxygenated organic compound is the entire molded article The molded object which is 20 mass% or less with respect to mass.
[13] The molded article according to [12], wherein the thermoplastic resin is hydrophobic and the oxygen-containing organic compound is hydrophilic.
[14] The content ratio of the thermoplastic resin in the region from the surface where one of the thermoplastic resin is contained to the thickness of 1 μm, which is one of the surfaces of the molded product, is C1 mass%, from the center plane of the molded product When the content of the thermoplastic resin in the region within the range of thickness ± 0.5 μm is C2 mass%, the value according to C1 / C2 is 0.25 or more and 3 or less [12] or [13] body.
[15] The molded article according to any one of [12] to [14], which has a total light transmittance of 70% or more.
[16] The molded article according to any one of [12] to [15] having a haze of 20% or less.
[17] The molded article according to any one of [12] to [16], which has a flexural modulus of 7 GPa or more at 23 ° C. and a relative humidity of 50%.
[18] A molded article comprising the step of heat and pressure molding the sheet according to any one of [1] to [11], wherein the molding temperature in the heat and pressure molding step is the melting point ± 20 ° C. of the thermoplastic resin Manufacturing method.
The laminated body which has a molded object and the resin layer in any one of [19] [12]-[17].
[20] The laminate according to [19], wherein the resin layer contains polycarbonate.
[21] The laminate according to [19] or [20], having a flexural modulus of 2.5 GPa or more at 23 ° C. and a relative humidity of 50%, and a linear thermal expansion coefficient of 200 ppm / K or less.

  According to the present invention, it is possible to obtain a sheet capable of forming a molded article excellent in transparency and strength. The molded articles formed from the sheet of the present invention have high total light transmittance, low haze, and high flexural modulus.

FIG. 1 is a graph showing the relationship between the amount of dropped NaOH and the electrical conductivity with respect to the fiber material. FIG. 2 is a cross-sectional view for explaining the configuration of the laminate of the present invention. FIG. 3 is a cross-sectional view for explaining the configuration of the laminate of the present invention. FIG. 4: is sectional drawing explaining an example of the manufacturing method of the laminated body of this invention.

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

(Sheet)
The present invention relates to a sheet containing fine fibrous cellulose having a fiber width of 1000 nm or less, a thermoplastic resin fiber, and a non-fibrous oxygenated organic compound. Here, the content of the oxygen-containing organic compound is 20% by mass or less based on the total mass of the sheet.
It is preferable that the sheet | seat of this invention is a sheet | seat for molded bodies used in order to shape | mold a molded object. By using the sheet of the present invention, a molded article excellent in transparency and strength can be formed.

  In the sheet of the present invention, the thermoplastic resin is contained as a thermoplastic resin fiber. For this reason, the thermoplastic resin is uniformly dispersed in the sheet and the molded body. The present inventors have found that the strength can be enhanced by uniformly dispersing the thermoplastic resin in the sheet and the molded body. Moreover, the present inventors also discovered that the transparency of a molded object can be improved by adding a predetermined amount of oxygen-containing organic compounds. As described above, in the present invention, since the thermoplastic tree is fibrous and contains a predetermined amount of the oxygen-containing organic compound, a molded article having both transparency and strength can be formed.

  The sheet of the present invention can form a molded article excellent in transparency. Specifically, the sheet of the present invention is preferably a sheet capable of forming a molded article having a total light transmittance of 70% or more. The total light transmittance of the molded product that can be molded into a sheet is more preferably 80% or more, further preferably 85% or more, and particularly preferably 90% or more. In addition, said total light transmittance is a total light transmittance of the molded object obtained by heat-pressing a sheet | seat on the conditions of melting | fusing point +50 degreeC of a thermoplastic resin fiber, and 10 MPa. The total light transmittance is a value measured in accordance with JIS K 7361 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).

  Moreover, it is preferable that the sheet | seat of this invention is a sheet | seat which can shape | mold the molded object whose haze is 20% or less. The haze of the molded product that can be molded into a sheet is more preferably 10% or less, still more preferably 5% or less, still more preferably 3% or less, and 2.7% or less Is particularly preferred. In addition, said haze is a haze of the molded object obtained by heat-pressing forming a sheet | seat on the conditions of melting | fusing point +50 degreeC of thermoplastic resin fiber, and 10 Mpa. The haze of the molded body is a value measured according to JIS K 7136 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).

  The sheet of the present invention is preferably a sheet capable of forming a molded product having a flexural modulus of 7 GPa or more at 23 ° C. and 50% relative humidity. The flexural modulus of the molded product which can be molded into a sheet is more preferably 8 GPa or more, still more preferably 10 GPa or more, and particularly preferably 12 GPa or more. Further, the upper limit value of the flexural modulus of the molded product that can be molded into a sheet is not particularly limited, but is preferably 20 GPa or less. In addition, said bending elastic modulus is a bending elastic modulus of the molded object obtained by heat-pressing forming a sheet | seat on the conditions of melting | fusing point +50 degreeC of a thermoplastic resin fiber, and 10 MPa. The flexural modulus at 23 ° C. and 50% relative humidity of the molded article is a value measured in accordance with JIS K 7074.

The density of the sheet of the present invention is preferably 1.0 g / cm ³ or more, more preferably 1.2 g / cm ³ or more, and still more preferably 1.4 g / cm ³ or more. Moreover, it is preferable that the density of the whole sheet | seat is 2.0 g / cm < ³ > or less. The density of the sheet is calculated from the basis weight and thickness of the sheet in accordance with JIS P 8118. The basis weight of the sheet can be calculated in accordance with JIS P 8124. In addition, the density of a sheet | seat is a density containing arbitrary components other than a cellulose fiber.

The sheet of the present invention is also characterized in that it is a nonporous sheet. Here, that the sheet is non-porous means that the density of the entire sheet is 1.0 g / cm ³ or more. If the density of the entire sheet is 1.0 g / cm ³ or more, this means that the porosity contained in the sheet is suppressed to a predetermined value or less, and this is distinguished from a porous sheet.
In addition, the non-porosity of the sheet is also characterized by the fact that the porosity is 15% by volume or less. The porosity of the sheet as referred to herein is simply determined by the following formula (a).
Formula (a): porosity (volume%) = [1-B / (M × A × t)] × 100
Here, A is the area of the sheet (cm ² ), t is the thickness of the sheet (cm), B is the mass of the sheet (g), and M is the density of cellulose.

  The content of the thermoplastic resin fiber contained in the sheet is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 15% by mass or more based on the total mass of the sheet. More preferably, it is particularly preferably 20% by mass or more. Further, the content of the thermoplastic resin fiber is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 45% by mass or less, and 40% by mass or less Is particularly preferred. Among them, the content of the thermoplastic resin fiber is preferably 15% by mass or more and 45% by mass or less, and more preferably 20% by mass or more and 40% by mass or less. By making content of a thermoplastic resin fiber into the said range, the molded object which has a more superior bending elastic modulus can be shape | molded.

  The content of the fine fibrous cellulose contained in the sheet is preferably 25% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more based on the total mass of the sheet. Preferably, it is 50% by mass or more. Moreover, it is preferable that it is 80 mass% or less, and, as for content of a fine fibrous cellulose fiber, it is more preferable that it is 70 mass% or less. By setting the content of the fine fibrous cellulose in the above range, physical entanglement between the fine fibrous celluloses and chemical crosslinking are sufficiently formed, so the strength of the sheet itself can be enhanced. It is possible to form a molded body having a further excellent flexural modulus.

  The content of the oxygen-containing organic compound contained in the sheet may be 20% by mass or less based on the total mass of the sheet. The content of the oxygen-containing organic compound is preferably 17% by mass or less, and more preferably 15% by mass or less. The content of the oxygen-containing organic compound is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. By setting the content of the oxygen-containing organic compound in the above range, a molded product having high transparency can be formed. Furthermore, by setting the content of the oxygen-containing organic compound in the above range, the flexibility of the sheet can be enhanced while maintaining an excellent flexural modulus.

<Use of sheet>
The sheet of the present invention is a sheet capable of forming a molded article excellent in strength and transparency. From the viewpoint of taking advantage of such characteristics, it is preferably used as a reinforcing material for substrates made of various resins. That is, the sheet of the present invention can be used as a reinforcing material for light-transmissive substrates such as various display devices and various solar cells, substrates for electronic devices, members for household appliances, window materials for various vehicles and buildings, interior materials, exteriors It is suitable as a reinforcing material for materials and packaging materials.

  Moreover, the molded object shape | molded from the sheet | seat of this invention can be used for displays, such as a liquid crystal display, a plasma display, an organic electroluminescent display, a field emission display, a rear projection television, etc. Furthermore, the molded body can be used as a touch panel, a substrate or a front plate of a solar cell, a color filter substrate or the like. In addition, the sheet of the present invention may be a sheet alone, various display devices, light transmitting substrates such as various solar cells, substrates of electronic devices, members of household appliances, window materials of various vehicles and buildings, interior materials, exteriors It can also be used as materials and packaging materials.

(Fine fibrous cellulose)
The fibrous cellulose raw material for obtaining the fine fibrous cellulose is not particularly limited, but it is preferable to use pulp in terms of availability and low cost. The pulp may include wood pulp, non-wood pulp and deinked pulp. As wood pulp, for example, hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolving pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen bleached kraft Chemical pulp, such as pulp (OKP), etc. are mentioned. Also, semi-chemical pulp such as semi-chemical pulp (SCP), chemiground wood pulp (CGP), mechanical pulp such as ground pulp (GP), thermo-mechanical pulp (TMP, BCTMP), etc. may be mentioned, but not particularly limited. . Non-wood pulps include cotton-based pulps such as cotton linters and cotton lint, non-wood-based pulps such as hemp, straw and bagasse, celluloses isolated from ascidians and seaweeds, chitin, chitosan and the like, but are not particularly limited . Examples of the deinked pulp include, but not particularly limited to, deinked pulp made from waste paper. The pulp of this embodiment may be used singly or in combination of two or more. Among the above-mentioned pulps, wood pulps containing cellulose and deinked pulps are preferable in terms of availability. Among wood pulps, chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose is high at the time of fiber refining (fibrillation), and decomposition of cellulose in the pulp is small, and fine fibers of long fibers having a large axial ratio It is preferable at the point from which fibrous cellulose is obtained. Among them, kraft pulp and sulfite pulp are most preferably selected. A sheet containing fine fibrous cellulose of long fibers with a large axial ratio tends to obtain high strength.

  The average fiber width of the fine fibrous cellulose is 1000 nm or less as observed by 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 still more preferably 2 nm or more and 10 nm or less. If the average fiber width of the fine fibrous cellulose is less than 2 nm, it dissolves in water as cellulose molecules, so the physical properties (strength, rigidity, and dimensional stability) as the fine fibrous cellulose tend to be difficult to express . The fine fibrous cellulose is, for example, monofibrillar cellulose having a fiber width of 1000 nm or less.

  The measurement of the fiber width by electron microscopic observation of fine fibrous cellulose is performed as follows. Prepare an aqueous suspension of fine fibrous cellulose with a concentration of 0.05% by mass or more and 0.1% by mass or less, cast this suspension on a hydrophilized carbon film-coated grid, and prepare a sample for TEM observation Do. If wide fibers are 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 fiber to be constructed. However, the sample, observation conditions and magnification are adjusted to satisfy the following conditions.

(1) One straight line X is drawn at an arbitrary position in the observation image, and 20 or more fibers cross the straight line X.
(2) Draw a straight line Y intersecting perpendicularly with the straight line in the same image, and 20 or more fibers cross the straight line Y.

  With respect to the observation image satisfying the above conditions, the width of the fiber intersecting with the straight line X and the straight line Y is visually read. Thus, three or more sets of images of at least non-overlapping surface portions are observed, and for each image, the width of the fiber intersecting the straight line X and the straight line Y is read. Thus, a fiber width of at least 20 x 2 x 3 = 120 is read. The average fiber width (sometimes simply referred to as "fiber width") of fine fibrous cellulose is the average value of the fiber widths read in this manner.

  The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 μm to 1000 μm, more preferably 0.1 μm to 800 μm, and particularly preferably 0.1 μm to 600 μm. By setting the fiber length within the above range, it is possible to suppress the destruction of the crystalline region of the fine fibrous cellulose and to make the slurry viscosity of the fine fibrous cellulose into an appropriate range. In addition, the fiber length of fine fibrous cellulose can be calculated | required from the image analysis by TEM, SEM, and AFM.

The fine fibrous cellulose preferably has a type I crystal structure. Here, the fact that the fine fibrous cellulose has an I-type crystal structure can be identified in a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418 Å) monochromatized with graphite. Specifically, it can be identified from having typical peaks at two positions of 2θ = 14 ° or more and 17 ° or less and 2θ = 22 ° or more and 23 ° or less.
The proportion of crystal form I in fine fibrous cellulose is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more.

  Although the ratio of the crystal parts contained in the fine fibrous cellulose is not particularly limited in the present invention, it is preferable to use cellulose having a crystallinity of 60% or more as determined by X-ray diffraction. The degree of crystallinity is preferably 65% or more, more preferably 70% or more. In this case, further excellent performance can be expected in terms of heat resistance and low linear thermal expansion. With regard to the degree of crystallinity, the X-ray diffraction profile is measured, and the pattern is determined 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 anion group. The anionic group is preferably, for example, at least one selected from a phosphoric acid group or a substituent derived from a phosphoric acid group (sometimes simply referred to as a phosphoric acid group), a carboxyl group and a sulfone group. It is more preferable that it is at least one selected from a group and a carboxyl group, and a phosphate group is particularly preferable.

The fine fibrous cellulose is preferably one having a phosphate group or a substituent derived from a phosphate group. The phosphate group is a divalent functional group corresponding to phosphoric acid from which a hydroxyl group has been removed. It is specifically a group represented by -PO ₃ H _2. The substituent derived from the phosphate group includes substituents such as a group obtained by condensation polymerization of a phosphate group, a salt of a phosphate group, and a phosphate ester group, and even if it is an ionic substituent, it is non-ionic substitution 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 formula (1), a, b, m and n each independently represent an integer (however, 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 Is an aromatic group, or a derivative group thereof; β is a monovalent or more cation composed of an organic substance or an inorganic substance.

  The content of the fine fibrous cellulose contained in the sheet is preferably 25% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more based on the total mass of the sheet. Preferably, it is 50% by mass or more. Moreover, it is preferable that it is 80 mass% or less of content of a fine fibrous cellulose fiber, and it is more preferable that it is 70 mass% or less. By setting the content of the fine fibrous cellulose in the above range, physical entanglement between the fine fibrous celluloses and chemical crosslinking are sufficiently formed, so the strength of the sheet itself can be enhanced. It is possible to form a molded body having a further excellent flexural modulus.

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

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

  As an example of the method of allowing compound A to act on the fiber material in the coexistence of compound B, a method of mixing powder or an aqueous solution of compound A and compound B with a dry or wet fiber material can be mentioned. Another example is a method of adding a powder or an aqueous solution of the compound A and the compound B to a slurry of a fiber material. Among them, the method of adding the aqueous solution of compound A and compound B to the fiber material in the dry state or adding the powder or the aqueous solution of compound A and compound B to the fiber material in the wet state because of high uniformity of reaction The method is preferred. Compound A and Compound B may be added simultaneously or separately. Alternatively, the compound A and the compound B to be tested first may be added as an aqueous solution, and excess chemical solution may be removed by pressing. The form of the fiber material is preferably cotton-like or thin sheet, but is not particularly limited.

The compound A used in the present 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 phosphoric acid, lithium salts of phosphoric acid, sodium salts of phosphoric acid, potassium salts of phosphoric acid, ammonium salts of phosphoric acid and the like, but are not particularly limited. Examples of lithium salts of phosphoric acid include lithium dihydrogen phosphate, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, lithium polyphosphate and the like. Examples of sodium salts of phosphoric acid include sodium dihydrogenphosphate, disodium hydrogenphosphate, trisodium phosphate, sodium pyrophosphate, sodium polyphosphate and the like. Examples of potassium salts of phosphoric acid include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate. Examples of ammonium salts of phosphoric acid include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, ammonium polyphosphate and the like.

  Among these, phosphoric acid and phosphoric acid are preferred from the viewpoint of high efficiency of introduction of a phosphoric acid group, easy improvement of defibrillation efficiency in a fibrillation step described later, low cost, and easy industrial application. Sodium salts or potassium salts of phosphoric acid and ammonium salts of phosphoric acid are preferred. Sodium dihydrogen phosphate or disodium hydrogen phosphate is more preferred.

  In addition, it is preferable to use Compound A as an aqueous solution because the uniformity of the reaction is enhanced and the efficiency of introducing a phosphate group is enhanced. 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 the phosphoric acid group is increased, and is preferably 3 or more and 7 or less from the viewpoint of suppressing hydrolysis of pulp fibers. The pH of the aqueous solution of the compound A may be adjusted by, for example, using a compound having a phosphoric acid group in combination of a compound exhibiting acidity and a compound exhibiting alkalinity, and changing its quantitative ratio. The pH of the aqueous solution of the compound A may be adjusted by adding an inorganic alkali or an organic alkali to a compound having an acid group among the compounds having a phosphoric acid group.

  The amount of compound A added to the fiber material is not particularly limited, but when the amount of compound A added is converted to the phosphorus atomic weight, the amount of phosphorus atom added to the fiber material (absolute dry mass) is 0.5% by mass to 100% by mass The following is preferable, 1 to 50 mass% is more preferable, and 2 to 30 mass% is the most preferable. If the addition amount of phosphorus atoms to the fiber raw material is within the above range, the yield of fine fibrous cellulose can be further improved. When the addition amount of phosphorus atoms to the fiber raw material exceeds 100% by mass, the effect of improving the yield becomes flat and the cost of the compound A used is increased. On the other hand, the yield can be increased by setting the addition amount of phosphorus atoms to the fiber raw material to the above lower limit value or more.

  As compound B used in this embodiment, urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like can be mentioned.

  The compound B is preferably used as an aqueous solution like the compound A. Further, it is preferable to use an aqueous solution in which both the compound A and the compound B are dissolved, because the uniformity of the reaction is enhanced. It is preferable that the addition amount of the compound B with respect to a fiber raw material (absolute dry mass) is 1 mass% or more and 500 mass% or less, more preferably 10 mass% or more and 400 mass% or less, 100 mass% or more and 350 mass% It is more preferable that it is the following, and it is especially preferable that it is 150 to 300 mass%.

  In addition to the compound A and the compound B, amides or amines may be included in the reaction system. Examples of the 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.

  It is preferable to heat-process in a phosphoric acid group introduction process. As the heat treatment temperature, it is preferable to select a temperature at which the phosphoric acid group can be efficiently introduced while suppressing the thermal decomposition or hydrolysis reaction of the fiber. Specifically, the temperature is preferably 50 ° C. to 300 ° C., more preferably 100 ° C. to 250 ° C., and still more preferably 150 ° C. to 200 ° C. For heating, a vacuum dryer, an infrared heater, or a microwave heater may be used.

  During the heat treatment, while the fiber material slurry to which Compound A is added contains water, if the time for which the fiber material is allowed to stand becomes long, Compound A, which is dissolved with water molecules, moves to the surface of the fiber material as it dries. Do. Therefore, unevenness may occur in the concentration of the compound A in the fiber raw material, and there is a possibility that the introduction of the phosphate group to the fiber surface may not progress uniformly. In order to suppress the occurrence of uneven concentration of compound A in the fiber raw material due to drying, use a very thin sheet-like fiber raw material or heat dry or vacuum dry while kneading or stirring the fiber raw material and compound A with a kneader etc. You should take the method.

  The heating device used for the heat treatment is preferably a device capable of constantly discharging the water held by the slurry and the water produced by the addition reaction to the hydroxyl groups of the fibers such as phosphoric acid groups, for example, an air-blowing oven. Etc. is preferred. In addition to the fact that hydrolysis of the phosphate ester bond, which is the reverse reaction of phosphorylation, can be suppressed by constantly draining the water in the system, acid hydrolysis of sugar chains in fibers can also be suppressed. And fine fibers with 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 after water is substantially removed from the fiber material slurry, and more preferably 1 second or more and 1000 seconds or less Preferably, it is 10 seconds or more and 800 seconds or less. In the present invention, by setting the heating temperature and the heating time to be in appropriate ranges, the introduction amount of the phosphate group can be made within the preferable range.

  The amount of introduced phosphoric acid group is preferably 0.1 mmol / g or more and 3.5 mmol / g or less per 1 g (mass) of fine fibrous cellulose, more preferably 0.14 mmol / g 2.5 mmol / g or less, 0 2 mmol / g 2.0 mmol / g or less is more preferable, 0.2 mmol / g 1.8 mmol / g or less is more preferable, 0.4 mmol / g 1.8 mmol / g or less is particularly preferable, and most preferably 0.6 mmol / g 1. It is 8 mmol / g or less. By making the introduction amount of the phosphate group within the above range, it is possible to facilitate the miniaturization of the fiber raw material and to enhance the stability of the fine fibrous cellulose. Moreover, the viscosity of the slurry of fine fibrous cellulose can be adjusted in an appropriate range by making the introduction amount of a phosphoric acid group into the said range.

  The amount of phosphate group introduced into the fiber material can be measured by conductivity titration. Specifically, the fineness is carried out by the defibration treatment step, and the obtained fine fibrous cellulose-containing slurry is treated with an ion exchange resin, and then the change in electric conductivity is obtained while adding an aqueous solution of sodium hydroxide, The introduced amount can be measured.

  In conductivity titration, the addition of alkali gives the curve shown in FIG. At the beginning, the electrical conductivity drops sharply (hereinafter referred to as "first region"). Thereafter, the conductivity starts to rise slightly (hereinafter referred to as "the second region"). After that, the increment of conductivity increases (hereinafter, referred to as "third region"). That is, three regions appear. Among them, 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 Become equal. When the phosphoric acid group causes condensation, the weakly acidic group is apparently lost, and the amount of alkali required for the second region is smaller than the amount of alkali required for the first region. On the other hand, since the amount of strongly acidic groups is the same as the amount of phosphorus atoms regardless of the presence or absence of condensation, the amount of introduction of phosphoric acid groups (or the amount of phosphoric acid groups) or the amount of introduction of substituents (or the amount of substitution groups) When said, it represents the amount of strongly acidic groups. 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 slurry to be titrated to obtain a substituent introduction amount (mmol / g).

  The phosphate group introduction step may be performed at least once, but can be repeated multiple times. In this case, more phosphate groups are introduced, which is preferable.

<Alkali treatment>
In the case of producing fine fibrous cellulose, an alkali treatment may be performed between the phosphoric acid group introduction step and the defibration treatment step described later. Although it does not specifically limit as the method of an alkali treatment, For example, the method of immersing phosphate group introduction | transduction fiber in an alkali solution is mentioned.
The alkaline compound contained in the alkaline solution is not particularly limited, but may be an inorganic alkaline compound or an organic alkaline compound. The solvent in the alkaline solution may be either water or an organic solvent. The solvent is preferably a polar solvent (water or a polar organic solvent such as alcohol), more preferably an aqueous solvent containing at least water.
Among the alkali solutions, sodium hydroxide aqueous solution or potassium hydroxide aqueous solution is particularly preferable because of high versatility.

The temperature of the alkali solution in the alkali treatment step is not particularly limited, but is preferably 5 ° C. or more and 80 ° C. or less, and more preferably 10 ° C. or more and 60 ° C. or less.
The immersion time in the alkali solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes to 30 minutes, and more preferably 10 minutes to 20 minutes.
The use amount of the alkali solution in the alkali treatment is not particularly limited, but is preferably 100% by mass or more and 100000% by mass or less, and is 1000% by mass or more and 10000% by mass or less based on the absolute dry mass of the phosphate group-introduced fiber Is more preferred.

  In order to reduce the amount of alkali solution used in the alkali treatment step, the phosphate group-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 phosphate group-introduced fiber with water or an organic solvent before the defibration treatment step.

<Disintegration processing>
The phosphate group-introduced fiber is subjected to disintegration processing in a disintegration processing step. In the defibration treatment step, fibers are usually defibrated using a defibration treatment device to obtain a fine fibrous cellulose-containing slurry, but the treatment device and treatment method are not particularly limited.
As the defibration processing apparatus, a high-speed fibrillation machine, a grinder (millstone type crusher), a high pressure homogenizer, an ultrahigh pressure homogenizer, a high pressure collision type crusher, a ball mill, a bead mill, etc. can be used. Alternatively, use an apparatus for wet grinding such as a disc refiner, a conical refiner, a twin screw kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic disperser, or a beater as a defibration treatment apparatus. You can also. The defibration processing apparatus is not limited to the above. As a preferable defibration treatment method, a high-speed fibrillation machine, a high pressure homogenizer, and an ultrahigh pressure homogenizer, which are less affected by the grinding media and less likely to be contaminated, can be mentioned.

  At the time of the defibration treatment, it is preferable to dilute the fiber raw material with water and an organic solvent singly or in combination to form a slurry, but it is not particularly limited. As the dispersion medium, polar organic solvents can be used in addition to water. Preferred polar organic solvents include, but are not particularly limited to, alcohols, ketones, ethers, dimethylsulfoxide (DMSO), dimethylformamide (DMF), and dimethylacetamide (DMAc). As alcohols, methanol, ethanol, n-propanol, isopropanol, n-butanol, or t-butyl alcohol etc. are mentioned. Examples of ketones include acetone or methyl ethyl ketone (MEK). Examples of ethers include diethyl ether or tetrahydrofuran (THF). The dispersion medium may be one type, or two or more types. The dispersion medium may also contain solid components other than the fiber material, such as urea having hydrogen bonding property.

  In the present invention, the fibrillation treatment may be carried out after concentrating and drying the fine fibrous cellulose. In this case, the method of concentration and drying is not particularly limited, and examples thereof include a method of adding a thickener to a slurry containing fine fibrous cellulose, a method of using a generally used dehydrator, a press, and a dryer. Also, known methods can be used, such as the methods described in WO2014 / 024876, WO2012 / 107642, and WO2013 / 121086. Alternatively, concentrated fine fibrous cellulose may be sheeted. The sheet can also be crushed and subjected to disintegration processing.

  As an apparatus used for pulverizing fine fibrous cellulose, a high-speed fibrillation machine, a grinder (stone mill type crusher), a high pressure homogenizer, an ultra high pressure homogenizer, a high pressure collision type crusher, a ball mill, a bead mill, a disc type refiner, a conical An apparatus for wet grinding such as a refiner, a twin screw kneader, a vibration mill, a homomixer under high speed rotation, an ultrasonic dispersion machine, a beater, etc. can also be used, but is not particularly limited.

  The fine fibrous cellulose-containing substance having a phosphoric acid group obtained by the method described above is a fine fibrous cellulose-containing slurry, and may be diluted with water so as to have a desired concentration.

(Thermoplastic resin fiber)
The sheet of the present invention contains a thermoplastic resin fiber. The thermoplastic resin fiber is also called a matrix resin because it forms a binding point at the intersection of fiber components or a matrix at the time of heat and pressure treatment.

  As a thermoplastic resin which comprises a thermoplastic resin fiber, For example, styrenic resin, acrylic resin, aromatic polycarbonate resin, aliphatic polycarbonate resin, aromatic polyester resin, aliphatic polyester resin, aliphatic polyolefin Examples thereof include, but are not limited to, system resins, cyclic olefin resins, polyamide resins, polyphenylene ether resins, thermoplastic polyimide resins, polyacetal resins, polysulfone resins, noncrystalline fluorine resins and the like. Among them, the thermoplastic resin constituting the thermoplastic resin fiber is preferably an aromatic polyester resin, an aliphatic polyester resin, an aliphatic polyolefin resin, an aromatic polycarbonate resin, or an aliphatic polycarbonate resin. More specifically, the thermoplastic resin is, for example, at least one selected from polylactic acid, polybutylene succinate, ethylene-vinyl alcohol copolymer, amorphous PET, polypropylene, acid-modified polypropylene, polycarbonate and polyethylene. It is preferable that it is at least one selected from polylactic acid, ethylene-vinyl alcohol copolymer, polyethylene terephthalate and polypropylene. As the thermoplastic resin, any one of the above-described resins may be used alone, or two or more different resins may be used.

  The fiber length (number average fiber length) of the thermoplastic resin fiber is preferably 0.5 mm or more, more preferably 1 mm or more, and still more preferably 3 mm or more. The fiber length (number average fiber length) of the thermoplastic resin fiber is preferably 100 mm or less, more preferably 50 mm or less, and still more preferably 25 mm or less. By setting the fiber length of the thermoplastic resin fiber in the above range, it is possible to suppress the thermoplastic resin fiber from falling off from the sheet, and it is possible to obtain a sheet excellent in handling property. In addition, by setting the fiber length of the thermoplastic resin fiber within the above range, the dispersibility of the thermoplastic resin fiber can be improved, so that it is possible to form a molded article excellent in strength.

  The fiber diameter (number average fiber diameter) of the thermoplastic resin fiber is preferably 0.5 μm or more, more preferably 1 μm or more, and still more preferably 3 μm or more. The fiber diameter (number average fiber diameter) of the thermoplastic resin fiber is preferably 50 μm or less, more preferably 25 μm or less, and still more preferably 15 μm or less.

  The thermoplastic resin fiber is preferably a hydrophobic thermoplastic resin fiber. The hydrophobic thermoplastic resin fiber preferably has an SP value of, for example, 13.0 or less, and may be less than 9.0.

  The content of the thermoplastic resin fiber contained in the sheet is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 15% by mass or more based on the total mass of the sheet. More preferably, it is particularly preferably 20% by mass or more. Further, the content of the thermoplastic resin fiber is preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 45% by mass or less, and 40% by mass or less Is particularly preferred. Among them, the content of the thermoplastic resin fiber is preferably 15% by mass or more and 45% by mass or less, and more preferably 20% by mass or more and 40% by mass or less. By making content of a thermoplastic resin fiber into the said range, the molded object which has a more superior bending elastic modulus can be shape | molded.

(Oxygen-containing organic compounds)
The sheet of the present invention comprises a non-fibrous oxygenated organic compound. Since the oxygen-containing organic compound is non-fibrous, the above-described fine fibrous cellulose and thermoplastic resin fibers are not included in the oxygen-containing organic compound.

  The oxygen-containing organic compound is preferably a hydrophilic organic compound. The hydrophilic oxygen-containing organic compound can improve the strength, density, chemical resistance and the like of the sheet. The hydrophilic oxygen-containing organic compound preferably has, for example, an SP value of 9.0 or more. The hydrophilic oxygen-containing organic compound is preferably one in which 1 g or more of the oxygen-containing organic compound is dissolved in, for example, 100 ml of ion-exchanged water.

  As the oxygen-containing organic compound, for example, polyethylene glycol, polyethylene oxide, casein, dextrin, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol etc.), polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, poly Hydrophilic polymers such as acrylic acid salts, polyacrylamide, acrylic acid alkyl ester copolymer, urethane copolymer, cellulose derivative (hydroxyethyl cellulose, carboxyethyl cellulose, carboxymethyl cellulose etc.); hydrophilic substances such as glycerin, sorbitol, ethylene glycol etc. And low molecular weight molecules. Among these, polyethylene glycol, polyethylene oxide, glycerin and sorbitol are preferable from the viewpoint of improving the strength, density, chemical resistance and the like of each sheet, and at least one selected from polyethylene glycol and polyethylene oxide is more preferable. preferable.

  The oxygen-containing organic compound is preferably an organic compound containing an oxyalkylene structure. The oxyalkylene structure refers to a structure in which an oxygen atom is introduced into the alkylene chain. The alkylene chain in the oxyalkylene structure may be linear, branched or cyclic. The oxyalkylene structure preferably contains an oxyethylene group or an oxypropylene group, and more preferably contains an oxyethylene group. In addition, the oxygen-containing organic compound may contain a polyoxyalkylene structure that contains an oxyalkylene group repeatedly two or more times. The polyoxyalkylene structure preferably contains a polyoxyethylene group or a polyoxypropylene group, and more preferably contains a polyoxyethylene group.

  The oxygen-containing organic compound is preferably an organic compound polymer having a molecular weight of 50,000 or more and 8,000,000 or less. The molecular weight of the oxygen-containing organic compound is preferably 100,000 or more and 5,000,000 or less, but may be, for example, a low molecular weight molecule having a molecular weight of less than 1,000.

  The content of the oxygen-containing organic compound contained in the sheet may be 20% by mass or less based on the total mass of the sheet. The content of the oxygen-containing organic compound is preferably 17% by mass or less, and more preferably 15% by mass or less. The content of the oxygen-containing organic compound is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. By setting the content of the oxygen-containing organic compound in the above range, a molded product having high transparency can be formed. Furthermore, by setting the content of the oxygen-containing organic compound in the above range, the flexibility of the sheet can be enhanced while maintaining an excellent flexural modulus.

(Production method of sheet)
The process of producing the sheet comprises the steps of obtaining a slurry containing fine fibrous cellulose having a fiber width of 1000 nm or less, thermoplastic resin fibers, and a non-fibrous oxygenated organic compound, and coating this slurry on a substrate Or a step of making a slurry. Among them, the sheet manufacturing process applies a slurry (hereinafter, also simply referred to as a slurry) containing fine fibrous cellulose, a thermoplastic resin fiber, and a non-fibrous oxygenated organic compound on a substrate It is preferable to include a process.

  In the step of obtaining the slurry, the content of the oxygen-containing organic compound is adjusted to 20% by mass or less with respect to the total mass of the solid content contained in the slurry. The content of the oxygen-containing organic compound in the slurry is preferably 17% by mass or less, and more preferably 15% by mass or less. The content of the oxygen-containing organic compound is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more.

<Coating process>
The coating step is a step of obtaining a sheet by coating the slurry on a substrate and drying it to peel the formed sheet from the substrate. A sheet can be continuously produced by using a coating device and a long base material. The concentration of the slurry to be coated is not particularly limited, but is preferably 0.05% by mass or more and 5% by mass or less.

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

  In the coating process, when the viscosity of the slurry is low and the slurry develops on the substrate, the frame for blocking can be fixed and used on the substrate in order to obtain a sheet having a predetermined thickness and basis weight. Good. The quality of the frame for blocking is not particularly limited, but it is preferable to select one that can be easily peeled off the end of the sheet adhering after drying. Among them, one obtained by molding a resin plate or a metal plate is preferable, but it is not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, etc., metal plates such as aluminum plates, zinc plates, copper plates, iron plates and the like, and their surfaces oxidized, stainless steel A plate, a brass plate or the like can be used.

  As a coating machine which coats a slurry, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater etc. can be used, for example. A die coater, a curtain coater, and a spray coater are preferred because the thickness can be made more uniform.

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

In the coating step, it is preferable to coat the slurry so that the finished basis weight of the sheet is 10 g / m ² or more and 100 g / m ² or less, preferably 20 g / m ² or more and 50 g / m ² or less. By coating so that a basis weight may become in the said range, the sheet | seat excellent in intensity | strength is obtained.

  It is preferable that the manufacturing process of a sheet | seat includes the process of drying the slurry coated on the base material. The drying method is not particularly limited, but it may be either a non-contact drying method or a method of drying while restraining the sheet, or a combination thereof.

  The non-contact drying method is not particularly limited, but a method of heating and drying by hot air, infrared rays, far infrared rays or near infrared rays (heat drying method), a method of vacuum drying (vacuum drying method) may be applied. Can. Although the heat drying method and the vacuum drying method may be combined, the heat drying method is usually applied. Drying by infrared light, far infrared light or near infrared light can be performed using an infrared light device, a far infrared light device or a near infrared light device, but is not particularly limited. The heating temperature in the heating and drying method is not particularly limited, but is preferably 20 ° C. or more and 120 ° C. or less, and more preferably 25 ° C. or more and 105 ° C. or less. The dispersion medium can be volatilized quickly if the heating temperature is at least the lower limit, and the cost required for heating can be suppressed and the fine fibrous cellulose can be prevented from being discolored by heat if the heating temperature is at least the upper limit. .

  After drying, the obtained sheet is peeled from the substrate, but in the case where the substrate is a sheet, the sheet and the substrate are laminated and wound up, and the sheet is peeled from the process substrate just before using the sheet. May be

<Paper-making process>
The manufacturing process of the sheet may include a process of making a slurry. Examples of the paper making machine in the paper making process include continuous paper machines such as long mesh type, circular net type and inclined type, and a multilayer paper making machine combining these. In the paper making process, known paper making such as hand paper making may be performed.

  In the paper making process, the slurry is filtered and dewatered on a wire to obtain a wet paper sheet, which is then pressed and dried to obtain a sheet. The concentration of the slurry is not particularly limited, but is preferably 0.05% by mass or more and 5% by mass or less. When the slurry is filtered and dewatered, it is not particularly limited as a filter cloth at the time of filtration, but it is important that the fine fibrous cellulose and the oxygen-containing organic compound do not pass through and the filtration rate does not become too slow. Such a filter cloth is not particularly limited, but a sheet made of an organic polymer, a woven fabric, and a porous membrane 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 thereof include porous films of polytetrafluoroethylene with a pore diameter of 0.1 μm to 20 μm, such as 1 μm, and woven fabrics of polyethylene terephthalate or polyethylene with a pore diameter of 0.1 μm to 20 μm, such as 1 μm, but are not particularly limited.

  Although it does not specifically limit as a method to manufacture a sheet | seat from a slurry, For example, the method of using the manufacturing apparatus as described in WO2011 / 2013567, etc. are mentioned. This manufacturing apparatus discharges a slurry containing fine fibrous cellulose onto the top surface of an endless belt, squeezes the dispersion medium from the discharged slurry to form a web, and the web is dried to form a fiber sheet. And a drying section to produce. An endless belt is disposed from the water squeezing section to the drying section, and the web generated in the water squeezing section is conveyed to the drying section while being placed on the endless belt.

  The dehydrating method that can be adopted is not particularly limited, but the dehydrating method usually used in the production of paper may be mentioned, and a method of dehydrating with a long mesh, circular net, inclined wire or the like and then dehydrating with a roll press is preferable. Further, the drying method is not particularly limited, and examples thereof include methods used in the production of paper. For example, methods such as a cylinder drier, a Yankee drier, hot air drying, a near infrared heater, and an infrared heater are preferable.

(Molded body)
The present invention also relates to a molded article containing fine fibrous cellulose having a fiber width of 1000 nm or less, a thermoplastic resin, and a non-fibrous oxygen-containing organic compound. Here, the content of the oxygen-containing organic compound contained in the molded product is 20% by mass or less with respect to the total mass of the molded product. That is, the molded object of this invention is a molded object obtained by heat-pressing the sheet | seat mentioned above.

  The thermoplastic resin is preferably hydrophobic and the oxygen-containing organic compound is preferably hydrophilic. That is, the non-fibrous oxygen-containing organic compound contained in the molded body does not contain the thermoplastic resin and naturally does not contain the fine fibrous cellulose.

  In the sheet of the present invention, the thermoplastic resin is contained as a thermoplastic resin fiber. For this reason, in the molded object obtained by shape | molding a sheet | seat, the thermoplastic resin is disperse | distributed substantially uniformly. Specifically, the content of the thermoplastic resin in a region from the surface of one of the molded articles containing the thermoplastic resin in a large area to a thickness of 1 μm is C1 mass%, and the center of the molded article is When the content of the thermoplastic resin in a region within a range of thickness ± 0.5 μm from the surface is C2 mass%, the value of C1 / C2 is preferably 0.25 or more and 3 or less. The value of C1 / C2 is more preferably 0.5 or more and 2 or less, and still more preferably 0.7 or more and 1.5 or less.

The value of C1 / C2 is calculated by the following method.
First, the surface layer on one side of the molded body and the surface layer on the other side are cut out with an ultramicrotome (manufactured by JEOL, UC-7) to a thickness of 1 μm to obtain a thin film. Further, a region (thickness 1 μm) within the range of thickness ± 0.5 μm from the central plane in the thickness direction of the molded body is cut out with an ultramicrotome (UC-7 manufactured by JEOL) to obtain a thin film. The weight of each film were measured, and W _1. Next, the thin film is boiled for 30 minutes in ion-exchanged water boiled at 100 ° C. to elute polyethylene oxide. Furthermore, the thin film is dried in a dryer at 100 ° C. for 30 minutes, and the weight W ₂ (the sum of the weight of the fine fibrous cellulose content and the thermoplastic resin content) is measured.
The membrane is then immersed in the solvent poured into a high pressure vessel, sealed and heated at 100 ° C. for 30 minutes. As a solvent used at this time, a solvent in which the thermoplastic resin dissolves is selected. For example, when ethylene-vinyl alcohol copolymer is used as the thermoplastic resin, dimethylsulfoxide is used as the solvent, when polylactic acid is used, chloroform is used as the solvent, and when polyethylene terephthalate is used, hexafluorocarbon is used as the solvent. When acid-modified polypropylene is used, xylene is used as a solvent.
Thereafter, the thin film is dried in a dryer at 100 ° C. for 30 minutes, and the weight W ₃ (weight of fine fibrous cellulose content) is measured. Next, the content C (%) of the thermoplastic resin is calculated according to the following formula (1). Further, among the thermoplastic resin contents of the surface layer of one surface and the surface layer of the other surface, the one having a large value is C1, and the content ratio of the thermoplastic resin of the region including the central plane in the thickness direction is C2. Is divided by C2 to obtain a thermoplastic resin content gradient. The content rate gradient of the thermoplastic resin calculated in this manner is used as an index of the uniformity of the thermoplastic resin.
Formula (1): C = 100 × (W ₂ −W ₃ ) / W ₁

  The total light transmittance of the molded article of the present invention is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance is a value measured in accordance with JIS K 7361 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).

  The haze of the molded article of the present invention is preferably 20% or less, more preferably 10% or less, still more preferably 5% or less, and still more preferably 3% or less. It is particularly preferable that the content be 2.7% or less. The haze of the molded body is a value measured according to JIS K 7136 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).

  The flexural modulus at 23 ° C. and 50% relative humidity of the molded article of the present invention is preferably 7 GPa or more, more preferably 8 GPa or more, still more preferably 10 GPa or more, and 12 GPa or more Particularly preferred. The upper limit of the flexural modulus of the molded product is not particularly limited, but is preferably 20 GPa or less. The flexural modulus at 23 ° C. and 50% relative humidity of the molded article is a value measured in accordance with JIS K 7074.

  The total thickness of the molded body is preferably 10 μm or more, more preferably 30 μm or more, and still more preferably 50 μm or more. Further, the overall thickness of the molded body is not particularly limited, but is preferably 1 mm or less. By setting the overall thickness of the molded body within the above range, the strength can be further enhanced.

  In addition, content of the fine fibrous cellulose in a molded object, a thermoplastic resin, and an oxygen-containing organic compound respond | corresponds to each content in the sheet | seat mentioned above, and its preferable range is also the same.

<Use of molded body>
The molded article of the present invention is excellent in strength and transparency. From the viewpoint of taking advantage of such characteristics, it is preferably used as a reinforcing material for substrates made of various resins. That is, the molded article of the present invention includes reinforcing materials for light-transmitting substrates such as various display devices and various solar cells, substrates for electronic devices, members for household appliances, window materials for various vehicles and buildings, interior materials, It is suitable as a reinforcing material for exterior materials and packaging materials.

  Moreover, the molded object of this invention can be used for displays, such as a liquid crystal display, a plasma display, an organic electroluminescent display, a field emission display, a rear projection television, etc. Furthermore, the molded body can be used as a touch panel, a substrate or a front plate of a solar cell, a color filter substrate or the like. Further, the molded article of the present invention is a molded article alone, various display devices, light transmissive substrates such as various solar cells, substrates of electronic devices, members of household appliances, window materials of various vehicles and buildings, interior materials It can also be used as packaging materials and packaging materials.

(Method of manufacturing molded body)
The step of producing the molded body includes the step of heat and pressure molding the above-mentioned sheet. Here, the molding temperature in the heat and pressure molding step is the melting point of the thermoplastic resin ± 20 ° C.

  The molded product may be formed by laminating the sheets singly or in a desired thickness and heating / pressing with a heat press, or heat / pressure using a mold preheated with an infrared heater or the like in advance. It is molded with In addition, the molded body may have a multilayer structure, and in such a case, sheets of other types may be laminated and heat and pressure molded by heat pressing. The molded body is processed using a general heat and pressure molding method.

  As a method of press molding, an autoclave method and a die press method are preferably mentioned among various existing press molding methods. The autoclave method is preferred from the viewpoint of obtaining high-quality molded articles with few voids. On the other hand, from the viewpoint of the amount of energy used in facilities and molding processes, simplification of molding jigs and auxiliary materials used, molding pressure and freedom of temperature, gold is used for molding using a metal mold It is preferable to use a mold pressing method, which can be selected according to the application.

  A heat and cool method or a stamping method can be employed as the mold pressing method. In the heat and cool method, a sheet is placed in a mold in advance, pressed and heated together with mold clamping, and then, while the mold is clamped, the sheet is cooled by cooling the mold to obtain a molded body It is a method. In the stamping molding method, the sheet is previously heated by a heating device such as a far infrared heater, a heating plate, a high temperature oven, dielectric heating, etc., and the resin is melted and placed in the molded resin in a softened state, then the mold is closed. It is a method of performing mold clamping and then pressure cooling. In addition, when the molding temperature is relatively low, for example, in the case of obtaining a low density molded body, a hot press method can also be adopted.

  Molds for molding are roughly classified into two types, one is a closed mold used for casting, injection molding and the like, and the other is an open mold used for press molding and forging. When the sheet of the present invention is used, any mold can be used depending on the application. Although an open mold is preferable from the viewpoint of excluding the decomposition gas and mixed air at the time of molding out of the mold, in order to suppress the outflow of the excessive resin, the open part is reduced as much as possible during the molding process. It is also preferable to adopt a shape that suppresses outflow from the mold.

  Specifically, when forming a formed body from a sheet, the sheet is preferably heated to a temperature of 150 to 600 ° C., and more preferably heated to 160 to 250 ° C. In addition, it is preferable that a heating temperature is a temperature which the thermoplastic resin fiber in a sheet | seat flows, and it is a temperature range which does not fuse | melt fine fibrous cellulose.

  As a pressure at the time of shape | molding a molded object, 5-20 Mpa is preferable. In addition, the temperature rising rate until reaching the desired holding temperature is preferably 3 to 20 ° C./min, and the holding time at the desired heat pressing temperature is 1 to 30 minutes, and then the temperature for removing the formed body (200 ° C. It is preferable to set a cooling rate of 3 to 20 ° C./min while maintaining the pressure up to the following.

(Laminate)
The present invention may relate to a laminate having the above-described molded body and a resin layer. The laminate may contain one layer each of the molded body and the resin layer, or may contain plural layers each of the molded body and the resin layer.

  FIGS. 2 and 3 show diagrams illustrating the configuration of the laminate of the present invention. As shown in FIG. 2, in the laminate 20 of the present invention, the molded body 10 and the resin layer 6 are preferably a laminate. Moreover, as shown in FIG. 3, the laminate 20 of the present invention may have the resin layer 6 on both sides of the molded body 10. Also, an adhesive layer (not shown) may be provided between the molded body 10 and the resin layer 6, and in this case, the molded body 10 and the resin layer 6 are laminated via the adhesive layer. . Furthermore, the laminate 20 preferably has a five-layer configuration in which the resin layer 6, the molded body 10, the resin layer 6, the molded body 10, and the resin layer 6 are laminated in this order.

<Resin layer>
The resin layer is a layer mainly composed of a synthetic resin. The content of the synthetic resin with respect to the total mass of the resin layer can be, for example, 80% by mass or more and 100% by mass or less. The type of synthetic resin is preferably, for example, at least one of polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyimide, polystyrene, polyacrylonitrile, and poly (meth) acrylate. Among them, polycarbonate having excellent moldability and high transparency is more preferable.

  As a polycarbonate which comprises a resin layer, aromatic polycarbonate-type resin and aliphatic polycarbonate-type resin are mentioned, for example. Specific polycarbonate resins include, for example, polycarbonate resins described in Japanese Patent No. 4985573 and the like.

  The resin layer may contain optional components other than the synthetic resin. Examples of the optional components include known components used in the resin film field such as fillers, pigments, dyes, ultraviolet absorbers and the like.

As a thickness of one layer of a resin layer, 100 micrometers or more are preferable, for example, 500 micrometers or more are more preferable, and 1000 micrometers or more are more preferable. The mechanical strength of a laminated body will fully be stabilized as it is 100 micrometers or more. The upper limit of the thickness of the resin layer is not particularly limited, and may be appropriately set depending on the application, and may be, for example, about 10 mm to 50 mm.
Here, the thickness of the resin layer constituting the laminate is measured by cutting the cross section of the laminate by Ultramicrotome UC-7 (manufactured by JEOL) and observing the cross section with an electron microscope, a magnifying glass or visual observation. It is a value.

<Adhesive layer>
An adhesive bond layer is a layer which bonds a molded object and a resin layer (joining). The laminate of the present invention may have an adhesive layer for bonding the molded body and the resin layer.

When forming an adhesive layer, it is preferable to apply | coat with an adhesive containing coating liquid on a molded object. The dry coating amount at this time is preferably 0.5 g / m ² or more and 5.0 g / m ² or less, more preferably 1.0 g / m ² or more and 4.0 g / m ² or less, and 1.5 g / m ² or more 3.0 g / m ² or less is more preferable. Sufficient adhesion between the molded body and the resin layer can be obtained as the above lower limit value is achieved, and the mechanical strength is further improved. The total light transmittance of the whole laminated body can be improved as it is below the said upper limit, and haze can be restrained low.

The thickness of one layer of the adhesive layer is, for example, preferably 0.1 μm to 30 μm, more preferably 0.5 μm to 10 μm, and still more preferably 1 μm to 7 μm. Sufficient adhesion between the molded body and the resin layer can be obtained as the above lower limit value is achieved, and the mechanical strength is further improved. The total light transmittance of the whole laminated body can be improved as it is below the said upper limit, and haze can be restrained low.
Here, the thickness of the adhesive layer constituting the laminate is a value measured by cutting the cross section of the laminate by Ultramicrotome UC-7 (manufactured by JEOL) and observing the cross section with an electron microscope.

  The adhesive layer contains, as a main component, (meth) acrylic acid ester polymer, α-olefin copolymer, ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyurethane, styrene-butadiene copolymer, polyvinyl chloride, epoxy It is preferable to contain one or more adhesives selected from resin, melamine resin, silicone resin, casein, natural rubber, and starch. Here, “main component” means that the content is 50% by mass or more with respect to the total mass of the adhesive layer. Among them, it is more preferable to include a (meth) acrylic acid ester polymer from the viewpoint of the balance between the improvement of adhesion and mechanical strength and the improvement of transparency.

  The (meth) acrylic acid ester polymer is a polymer obtained by graft polymerization of synthetic resin other than (meth) acrylic resin such as epoxy resin and urethane resin, and (meth) acrylic acid ester and other monomer are copolymerized. And copolymers thereof. However, it is preferable that the mole fraction of monomers other than (meth) acrylic acid ester in the said copolymer is 50 mol% or less. Further, in the total mass of the (meth) acrylic acid ester polymer, the content of the synthetic resin other than the graft polymerized (meth) acrylic resin is preferably 50% by mass or less.

  The adhesive layer may contain a compound that forms a covalent bond with a functional group (such as a phosphate group) introduced to the fine fibrous cellulose. As a compound which forms a covalent bond, the compound containing at least 1 sort (s) selected from a silanol group, an isocyanate group, a carbodiimide group, an epoxy group, and an oxazoline group is mentioned, for example. Among the above compounds, a compound having a silanol group or an isocyanate group which is excellent in the reactivity with the functional group introduced to the fine fibrous cellulose is more preferable. By including such a compound in the main component of the adhesive, the adhesion between the sheets can be made stronger.

  The main component of the adhesive layer is more preferably a compound that induces physical interaction with the resin layer from the viewpoint of enhancing the adhesion to the resin layer. That is, it is preferable that the solubility parameter (SP value) of the main component of the adhesive layer and the resin layer be closer. The difference between the SP value of the main component of the adhesive layer and the resin layer is preferably 10 or less, more preferably 5 or less, and still more preferably 1 or less.

<Relative thickness of each layer>
It is preferable that the relationship of the relative thickness of the layer which mutually adjoins among the molded object and resin layer which comprise the laminated body of this invention is resin layer> molded object. According to this relationship, the molded body reinforces the resin layer, and the mechanical properties of the resin layer can be further improved by the molded body.

  The ratio of the thickness of the molded body to the thickness of the resin layer (the thickness of the resin layer / the thickness of the molded body) is preferably 10 or more, more preferably 20 or more, and still more preferably 30 or more. When it is 10 or more, the mechanical strength of the laminate is further improved. The upper limit of the thickness ratio is not particularly limited and may be appropriately set depending on the application, and may be, for example, 50 or more or 100 or more.

When a laminate is provided with at least one of a molded body and a resin layer, the ratio of the total thickness of the resin layer to the total thickness of the molded body (total of the thickness of the resin layer / total thickness of the molded body) 10 or more are preferable, 20 or more are more preferable, and 30 or more are more preferable. When it is 10 or more, the mechanical strength of the laminate is further improved. The upper limit of the thickness ratio is not particularly limited and may be appropriately set depending on the application, and may be, for example, 50 or more or 100 or more.
In addition, when the molded object with which the laminated body was equipped is one layer, the sum total of the thickness of the molded object with which the laminated body was equipped is the thickness of the molded object of the said 1 layer.

  The thickness of the laminate is not particularly limited, and for example, 0.5 mm or more is preferable, 1 mm or more is more preferable, and 2 mm or more is more preferable. By being 0.5 mm or more, it becomes easy to apply the layered product of the present invention to the use to which glass was conventionally applied.

  The total light transmittance of the laminate is not particularly limited, and is, for example, preferably 60% or more, more preferably 65% or more, and still more preferably 70% or more. By being 60% or more, it becomes easy to apply the laminated body of this invention to the use to which transparent glass was conventionally applied.

  The haze of the laminate is not particularly limited, and is, for example, preferably 20% or less, more preferably 15% or less, and still more preferably 10% or less. The lower the haze, the easier it is to apply the laminate of the invention to applications where conventionally transparent glass has been applied.

  The flexural modulus at 23 ° C. and 50% relative humidity of the laminate is preferably 2.5 GPa or more, and more preferably 3.0 GPa or more. The flexural modulus of the laminate is a value measured in accordance with JIS K 7074. Furthermore, the linear thermal expansion coefficient of the laminate is preferably 200 ppm / K or less, more preferably 100 ppm / K or less, and still more preferably 50 ppm / K or less. The linear thermal expansion coefficient of the laminate is a value measured using a thermomechanical analyzer (TMA7100 manufactured by Hitachi High-Tech Co., Ltd.). Specifically, the laminate is cut out by a laser cutter into a width of 3 mm and a length of 30 mm, which is set in a thermomechanical analyzer (TMA7100 manufactured by Hitachi High-Tech Co., Ltd.). The temperature is raised from room temperature to 180 ° C. at a rate of 5 ° C./min under conditions of nitrogen atmosphere. The linear thermal expansion coefficient is calculated from the measured values at 100 ° C. to 150 ° C. at this time.

<Use of laminate>
The laminate of the present invention is a transparent laminate having high mechanical strength and low haze. From the viewpoint of making use of the excellent optical properties, it is suitable for applications of light transmissive substrates such as various display devices and various solar cells. In addition, it is suitable for applications such as substrates of electronic devices, members of household appliances, window materials of various vehicles and buildings, interior materials, exterior materials, packaging materials, and the like.

(Method of manufacturing laminate)
It is preferable that the manufacturing process of the laminated body of this invention includes the process of heat-pressing, after laminating | stacking the molded object and resin layer which were mentioned above. When heat and pressure molding the laminate, the molded body and the resin layer are laminated one by one each or plural layers so as to obtain a desired configuration and heat pressure molded by a heat press, or by an infrared heater or the like in advance It is molded by heat and pressure molding using a preheated mold. A general heat and pressure molding method can be adopted for molding.
For the molding method and the mold, the method and mold described in the item of the method for producing a molded body can be used.

  Specifically, when the laminate is formed, it is preferable to heat one obtained by superposing the formed body and the resin layer to a temperature of 150 to 600 ° C, and more preferably to 160 to 250 ° C. The heating temperature is preferably a temperature at which the thermoplastic resin fiber in the molded body or the resin in the resin layer flows, and the temperature range in which the fine fibrous cellulose is not melted is preferable.

  As a pressure at the time of shape | molding a laminated body, 5-20 Mpa is preferable. In addition, the temperature rising rate until reaching the desired holding temperature is preferably 3 to 20 ° C./min, and the holding time at the desired heat pressing temperature is 1 to 30 minutes, and then the temperature for removing the formed body (200 ° C. It is preferable to set a cooling rate of 3 to 20 ° C./min while maintaining the pressure up to the following.

The laminate of the present invention can also be produced by bonding a molded body and a resin layer with an adhesive. The method of apply | coating an adhesive agent to the lamination | stacking surface of a molded object or a resin layer applies a well-known method. Specifically, an adhesive is applied to at least one of the surfaces to be the laminated surface of the molded product using a coater and the like, and dried to obtain a laminated material in which the molded product and the adhesive layer are laminated. There is a method of manufacturing a laminate by bonding a resin layer to the adhesive layer of the laminate.
In addition, the dry application quantity of the adhesive layer mentioned above can be adjusted by adjusting the quantity which apply | coats an adhesive agent suitably.

As a method (process) which joins a resin layer to the adhesive bond layer of a laminated material, the method of mounting the resin sheet material which comprises a resin layer on the adhesive bond layer of laminated material, and heat-pressing it is mentioned. In addition, the laminated material is placed in a mold for injection molding, and the adhesive layer is disposed on the injection space side (the center side of the inside of the mold) so that the adhesive layer is exposed, and the resin is heated and melted in the mold. And the resin layer made of the injected resin is bonded to the adhesive layer of the laminated material.
From the viewpoint of improving the adhesion between the molded body and the resin layer, it is preferable to manufacture the laminate by an injection molding method.

Below, an example of the manufacturing method of the laminated body by the injection molding method is demonstrated.
First, a resin sheet 36 to be placed in a mold for injection molding together with the molded body 10 is prepared. The resin sheet 36 becomes the resin layer 6 by being thermocompression-bonded to the molded body 10 by the injection pressure of the injected resin in the mold. In addition, when joining a molded object and a resin layer by an adhesive agent, it is good also as a laminated material which laminated | stacked the molded object 10 and the adhesive bond layer.
Subsequently, as shown in FIG. 4, the resin sheet 37 and the molded body 10 are sequentially placed on two places on the inner wall surface of the injection molding flat metal mold 35, and fixed with a heat resistant tape 34. Next, the flat metal mold 35 is assembled by arranging the inner wall surface of the flat metal mold 35 on which the resin sheet 37 and the molded body 10 are placed corresponding to the positions of the upper surface and the lower surface of the laminate 20 to be formed. Then, the resin which has been heated and melted from the injection port 35a is injected at an appropriate pressure, and molded at an appropriate temperature, an appropriate clamping force, and an appropriate holding time to obtain the laminate 20. If necessary, both end portions including the heat resistant tape 34 can be cut to obtain a laminate 20 of a finished product.

The pressure for injecting the resin is, for example, preferably 10 MPa or more and 500 MPa or less, more preferably 50 MPa or more and 400 MPa or less, and still more preferably 100 MPa or more and 300 MPa or less.
The resin melting temperature at the time of molding is, for example, preferably 100 ° C. or more and 400 ° C. or less, more preferably 150 ° C. or more and 400 ° C. or less, and still more preferably 200 ° C. or more and 400 ° C. or less.
The mold clamping force at the time of molding is, for example, preferably 200 kN or more and 100,000 kN or less, more preferably 500 kN or more and 50000 kN or less, and still more preferably 1000 kN or more and 10000 kN or less.
The holding time at the time of molding is, for example, preferably 0.1 seconds to 600 seconds, more preferably 1 seconds to 300 seconds, and still more preferably 10 seconds to 60 seconds.
As a mold temperature at the time of molding, for example, 100 ° C. or more and 400 ° C. or less is preferable, 100 ° C. or more and 300 ° C. or less is more preferable, and 150 ° C. or more and 250 ° C. or less is more preferable.

(Other aspects of laminate)
The laminated body of the present invention may have a configuration in which a molded body and an inorganic layer such as glass or metal are laminated. In addition, a thin film formed by a thin film forming method such as a vapor deposition method, a sputtering method, a vapor phase chemical growth method, an atomic layer deposition method may be laminated on the formed body.

  The features of the present invention will be more specifically described below with reference to examples and comparative examples. The materials, amounts used, proportions, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

Example 1
[Preparation of phosphorylation reagent]
265 g of sodium dihydrogen phosphate dihydrate and 197 g of disodium hydrogen phosphate were dissolved in 538 g of water to obtain an aqueous solution of a phosphoric acid compound (hereinafter referred to as "phosphorylation reagent").

[Phosphorylation]
Softened bleached kraft pulp (manufactured by Oji Holdings, Inc., 50% by mass moisture, 700 ml of Canadian standard freeness (CSF) measured according to JIS P 8121) is diluted with ion-exchanged water to a moisture content of 80% by mass , Pulp suspension was obtained. 210 g of the above-mentioned phosphorylation reagent was added to 500 g of this pulp suspension, and the mixture was dried occasionally while being occasionally kneaded with a draft dryer at 105 ° C (Yamato Scientific Co., Ltd., DKM400). Next, the mixture was heated for 1 hour while occasionally mixing with a fan dryer at 150 ° C. to introduce phosphoric acid groups into the cellulose. The amount of introduction of the phosphate group at this time was 0.98 mmol / g.

  The amount of introduced phosphoric acid group was measured by diluting cellulose with ion exchange water to a content of 0.2% by mass, treating with ion exchange resin, and titration using an alkali. In the treatment with ion exchange resin, 1/10 strongly acidic ion exchange resin (Amberjet 1024: Organo Corporation, conditioned) is added to a 0.2 mass% cellulose-containing slurry and shaken for 1 hour. The Then, it poured on the mesh of 90 micrometers of openings, and the resin and the slurry were isolate | separated. In the titration using an alkali, the change in the value of electric conductivity exhibited by the slurry was measured while adding a 0.1 N aqueous solution of sodium hydroxide to the fibrous cellulose-containing slurry after ion exchange. That is, the amount of alkali (mmol) required in the first region of the curve shown in FIG. 1 was divided by the solid content (g) in the slurry to be titrated to obtain a substituent introduction amount (mmol / g).

[Alkali treatment, cleaning]
Subsequently, 5000 ml of ion-exchanged water was added to the cellulose to which a phosphate group had been introduced, and after stirring and washing, it was dehydrated. The dewatered pulp was diluted with 5000 ml of ion-exchanged water, and 1N aqueous sodium hydroxide solution was added little by little while stirring until the pH became 12 or more and 13 or less, to obtain a pulp dispersion. Thereafter, the pulp dispersion was dewatered and washed by adding 5000 ml of deionized water. This dehydration washing was repeated once more.

[Machine processing]
Ion-exchanged water was added to the pulp obtained after washing and dewatering to obtain a pulp dispersion having a solid content concentration of 1.0% by mass. The pulp dispersion was treated using a high pressure homogenizer (Panda Plus 2000, manufactured by NiroSoavi) to obtain a cellulose dispersion. In the treatment with a high pressure homogenizer, the homogenization chamber was passed 5 times at an operating pressure of 1200 bar. Furthermore, this cellulose dispersion was treated using a wet atomization device (manufactured by Sugino Machine Co., Ltd., Ultimizer) to obtain a fine fibrous cellulose dispersion. In the processing using the wet atomization device, the processing chamber was passed five times at a pressure of 245 MPa. The average fiber width of the fine fibrous cellulose contained in the fine fibrous cellulose dispersion was 4 nm.

[Sheeting]
The concentration was adjusted so that the solid content concentration of the fine fibrous cellulose dispersion (A) was 0.5% by mass. Then, 0.5 of polyethylene oxide (Sumitomo Seika, PEO-18: molecular weight: 4.3 million to 4.8 million) as a non-fibrous oxygenated organic compound relative to 100 parts by mass of the fine fibrous cellulose dispersion (A) 20 parts by mass of a mass% aqueous solution was added to obtain a fine fibrous cellulose dispersion (B). Thereafter, as a thermoplastic resin fiber, ethylene-vinyl alcohol copolymer fiber (manufactured by Kuraray, S030: melting point 170 ° C., fiber diameter 9 μm, fiber length 5 mm), solid content 90 mass of fine fibrous cellulose dispersion (B) It was added and stirred so as to be 10 parts by mass with respect to parts. Next, the dispersion was weighed so that the finished basis weight of the sheet would be 75.0 g / m ² , spread on a commercially available acrylic plate, and dried with a thermostat at 35 ° C. and a relative humidity of 15%. In addition, the metal frame (gold frame of internal dimension 180 mm x 180 mm) for sealing was arrange | positioned on an acrylic board so that it might become a predetermined | prescribed basic weight. Thus, a sheet was produced.

[Molding (heat press)]
The above sheet was sandwiched by a stainless plate having a thickness of 2 mm and a size of 200 mm × 200 mm. In addition, as a stainless steel plate, what apply | coated the mold release agent (The Deck Co., Ltd. make, Tefrillies) to the clamping surface was used. Then, it was inserted into a heat press machine (30 ton press machine manufactured by Toyo Seiki Kogyo Co., Ltd.) set to normal temperature, heated to 180 ° C. under pressure of 1 MPa, and then pressurized to 10 MPa. After holding for 20 minutes in this state, it cooled to 30 degreeC over 5 minutes. A molded body was obtained by the above procedure.

Example 2
In the sheet formation of Example 1, the ethylene-vinyl alcohol copolymer fiber was added and stirred so as to be 30 parts by mass with respect to 70 parts by mass of the solid content of the fine fibrous cellulose dispersion (B). The other procedures were the same as in Example 1 to obtain sheets and molded articles.

Example 3
In the sheet formation of Example 1, ethylene-vinyl alcohol copolymer fiber was added and stirred so as to be 50 parts by mass with respect to 50 parts by mass of the solid content of the fine fibrous cellulose dispersion (B). The other procedures were the same as in Example 1 to obtain sheets and molded articles.

Example 4
In the sheet formation of Example 2, instead of the ethylene-vinyl alcohol copolymer fiber, a polylactic acid fiber (manufactured by Unitika, PL01: melting point 170 ° C., fiber diameter 40 μm, fiber length 3 mm) was added. The other procedures were the same as in Example 2 to obtain sheets and molded articles.

Example 5
In the sheet formation of Example 2, instead of the ethylene-vinyl alcohol copolymer fiber, a low melting point polyethylene terephthalate fiber (manufactured by Kuraray, N701Y: melting point 130 ° C., fiber diameter 23 μm, fiber length 5 mm) was added. Moreover, the temperature at the time of molding (heat pressing) was changed from 180 ° C. to 150 ° C. The other procedures were the same as in Example 2 to obtain sheets and molded articles.

Example 6
In the sheet formation of Example 2, instead of the ethylene-vinyl alcohol copolymer fiber, acid-modified polypropylene fiber (manufactured by Daiwabo Polytech, PZ-AD: melting point 160 ° C., fiber diameter 15 μm, fiber length 5 mm) was added. The other procedures were the same as in Example 2 to obtain a sheet and a molded body.

Comparative Example 1
Sheets and molded articles were obtained in the same manner as in Example 1 except that the addition of ethylene-vinyl alcohol copolymer fibers was not performed in the sheet formation of Example 1.

Comparative Example 2
In sheet formation of Example 2, the addition amount of polyethylene oxide 0.5 mass% aqueous solution was 100 mass parts with respect to 100 mass parts of fine fibrous cellulose dispersion liquid (A). The other procedures were the same as in Example 2 to obtain sheets and molded articles.

Comparative Example 3
[Wet sheet]
The fine fibrous cellulose dispersion (A) obtained in Example 1 is made of a hydrophilic polytetrafluoroethylene having a pore diameter of 0.45 μm manufactured by Advantech on a filter holder with an inner diameter of 70 mm (manufactured by Advantech, KG-90) Vacuum filtration was performed using a membrane filter to obtain a wet sheet. At this time, the fine fibrous cellulose dispersion (A) was weighed so that the basis weight calculated from the solid content of the sheet was 75.0 g / m ² .

[Pore treatment with high boiling point solvent]
9600 parts by mass of diethylene glycol ethyl methyl ether was added to the upper part of the wet sheet with respect to 100 parts by mass of the solid content of the wet sheet. After suction filtration of diethylene glycol ethyl methyl ether, the wet sheet was dried while being pressurized to 0.1 MPa with a cylinder drier heated to 105 ° C. to obtain a porous sheet.

[Resin impregnation to porous sheet]
The porous sheet was immersed in a thermoplastic resin composition (Arakawa Chemical Industries, Ltd., beam set 575 CB: urethane acrylate as a main component), and subjected to a pressure reduction treatment (pressure 50 kPa) for 12 hours. Thereafter, this was sandwiched between two glass plates and irradiated with ultraviolet light of 300 mJ / cm ² using a UV conveyor (ECS-4011 GX, manufactured by Eye Graphics Co., Ltd.) to cure the urethane acrylate resin composition. According to the above-described procedure, a sheet in which the thermoplastic resin impregnated in the fine fibrous cellulose sheet is composited is obtained. Thereafter, molding (heat press) was performed in the same manner as in Example 1 to obtain a molded body.

Comparative Example 4
Sheets and molded articles were obtained in the same manner as in Example 1 except that polyethylene oxide was not added in the sheet formation of Example 1.

<Measurement>
The molded objects obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were measured by the following method.

[Thickness]
The thickness of the molded body was measured with a stylus thickness gauge (Miritron 1202D, manufactured by Marle).

[Uniformity of thermoplastic resin]
The surface layer on one side of the molded body and the surface layer on the other side were cut out with an ultramicrotome (manufactured by JEOL, UC-7) to a thickness of 1 μm to obtain a thin film. Furthermore, a region (thickness 1 μm) within a range of thickness ± 0.5 μm from the central plane in the thickness direction of the molded body was cut out with an ultramicrotome (UC-7 manufactured by JEOL) to obtain a thin film. The weight of each film was measured and a W _1. Next, the thin film was boiled for 30 minutes with ion-exchanged water boiled at 100 ° C. to elute the polyethylene oxide. Further, the thin film was dried in a dryer at 100 ° C. for 30 minutes, and the weight W ₂ (the sum of the weight of the fine fibrous cellulose content and the thermoplastic resin content) was measured. The thin film was then poured into a high pressure vessel, immersed in the solvent described in Table 1, sealed, and heated at 100 ° C. for 30 minutes. Thereafter, the thin film was dried in a dryer at 100 ° C. for 30 minutes, and the weight W ₃ (weight of fine fibrous cellulose content) was measured. Subsequently, the content C (%) of the thermoplastic resin was calculated according to the following formula (1). Further, among the thermoplastic resin contents of the surface layer of one surface and the surface layer of the other surface, the one having a large value is C1, and the content ratio of the thermoplastic resin of the region including the central plane in the thickness direction is C2. Was divided by C2 to obtain a thermoplastic resin content gradient. The calculated content gradient of the thermoplastic resin was used as an index of the uniformity of the thermoplastic resin.
Formula (1): C = 100 × (W ₂ −W ₃ ) / W ₁

<Evaluation>
The molded articles obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were evaluated by the following methods.

[Total light transmittance]
The total light transmittance was measured using a haze meter (manufactured by Murakami Color Research Laboratory, HM-150) in accordance with JIS K 7361.

[Haze]
The haze was measured using a haze meter (manufactured by Murakami Color Research Laboratory, HM-150) in accordance with JIS K 7136.

[Flexural modulus]
The flexural modulus of the molded article was measured at 23 ° C. and 50% relative humidity using a universal material tester (Tensilon RTC-1250A manufactured by A & D Co., Ltd.) in accordance with JIS K 7074.

As is clear from Table 1, in Examples 1 to 6 in which thermoplastic resin fibers were added, a molded article having a high total light transmittance and a low haze could be formed. It was possible to improve a bending elastic modulus with respect to the comparative example 1 which is not adding the thermoplastic resin fiber. Moreover, the highest flexural modulus was obtained in Example 2 among Examples 1 to 3 in which ethylene-vinyl alcohol copolymer fiber was added as a thermoplastic resin fiber. It was suggested that the addition amount of the thermoplastic resin fiber has an optimum point.
On the other hand, in Comparative Example 2 in which the addition amount of polyethylene oxide was large, the haze was deteriorated, and the flexural modulus was also lowered. In Comparative Example 4 in which polyethylene oxide was not added, the haze was degraded and the total light transmittance was degraded. In addition, in Comparative Example 3 in which the porous sheet was impregnated with the thermoplastic resin, the uniformity of the thermoplastic resin was low, and the result was a decrease in bending elastic modulus as well as haze.

Example 101
[Molding of sheet and resin]
The molded product obtained in Example 1 is placed between two polycarbonate resin sheets (Panalite PC-1151 manufactured by Teijin Ltd .: thickness 1.0 mm, size 150 mm × 150 mm), thickness 2 mm, size 200 mm. It was sandwiched by a stainless plate of × 200 mm. In addition, as a stainless steel plate, what apply | coated the mold release agent (The Deck Co., Ltd. make, Tefrillies) to the clamping surface was used. Then, after inserting in the mini-test press (made by Toyo Seiki Kogyo Co., Ltd. make, MP-WCH) set to normal temperature and heating up to 180 degreeC under pressure of 1 Mpa, it pressurized to 10 Mpa. After holding for 5 minutes in this state, it was cooled to 30 ° C. over 5 minutes. According to the above-described procedure, a laminate in which a molded body and a polycarbonate resin layer are laminated was obtained.

Example 102
In Example 101, the molded article obtained in Example 2 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

<Example 103>
In Example 101, the molded article obtained in Example 3 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

<Example 104>
In Example 101, the molded article obtained in Example 4 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

Example 105
In Example 101, the molded article obtained in Example 5 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

<Example 106>
In Example 101, the molded article obtained in Example 6 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

Comparative Example 101
In Example 101, the molded body obtained in Comparative Example 1 was used. The other procedures were performed in the same manner as in Example 101 to obtain a laminate.

Comparative Example 102
In the molding of the resin of Example 101, no molded body was disposed. The other procedures were performed in the same manner as in Example 101 to obtain a polycarbonate resin sheet having a two-layer structure.

<Measurement>
The laminates obtained in Examples 101 to 106 and Comparative Example 101 and the polycarbonate resin sheets obtained in Comparative Example 102 were measured by the following methods.

[Thickness]
The thickness of the laminate and the polycarbonate resin sheet was measured with a stylus thickness gauge (Miritron 1202D, manufactured by Marle).

<Evaluation>
The laminates obtained in Examples 101 to 106 and Comparative Example 101 and the polycarbonate resin sheets obtained in Comparative Example 102 were evaluated by the following methods.

[Adhesiveness]
According to JIS K 5400, 100 squares of cuts were made, and the number of peeled squares after tape peeling was counted to evaluate the adhesion between the molded body and the resin layer.

[Flexural modulus]
The flexural modulus of the laminate and the polycarbonate resin sheet was measured at 23 ° C. and 50% relative humidity using a universal material tester (tensilon RTC-1250A manufactured by A & D Co., Ltd.) according to JIS K 7074. .

[Linear thermal expansion coefficient]
The laminate and the polycarbonate resin sheet were cut out into a width 3 mm × length 30 mm by a laser cutter. This is set in a thermomechanical analyzer (TMA7100 manufactured by Hitachi High-Tech Co., Ltd.) and heated from room temperature to 180 ° C at a rate of 5 ° C / min under conditions of 20 mm between chucks, 10 g load, and nitrogen atmosphere in tension mode. The The linear thermal expansion coefficient was calculated from the measured values at 100 ° C. to 150 ° C. at this time.

[Total light transmittance]
The total light transmittance of the laminate and the polycarbonate resin sheet was measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory, Inc.) in accordance with JIS K 7361.

[Haze]
The haze of the laminate and the polycarbonate resin sheet was measured in accordance with JIS K 7136 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory, Inc.).

As is clear from Table 2, in Examples 101 to 106 using a molded article containing a thermoplastic resin fiber, the adhesion between the molded article and the resin layer is excellent compared to Comparative Example 101 not containing a thermoplastic resin fiber. It was Moreover, in the example 101-106 using the molded object containing a thermoplastic resin fiber, compared with the polycarbonate resin sheet of the comparative example 102, the outstanding bending elastic modulus was obtained. Moreover, the linear thermal expansion coefficient was able to be reduced notably. Furthermore, in Examples 101 to 106, a laminate having a high total light transmittance and a small haze was obtained.
Thus, it was confirmed that the molded body can be used as a resin reinforcing sheet, and is particularly suitable as a resin reinforcing sheet with high transparency.

Reference Signs List 6 resin layer 10 molded body 20 laminated body 34 heat resistant tape 35 flat plate mold 35 a inlet 36 resin sheet

Claims (17)

A sheet comprising fine fibrous cellulose having a fiber width of 1,000 nm or less, a thermoplastic resin fiber, and a non-fibrous oxygen-containing organic compound,
The oxygen-containing organic compound is a polyalkylene oxide,
The thermoplastic resin constituting the thermoplastic resin fiber is at least one selected from polylactic acid, polybutylene succinate, ethylene-vinyl alcohol copolymer, amorphous PET, polypropylene, acid-modified polypropylene, polycarbonate and polyethylene Yes,
A sheet, wherein the content of the oxygen-containing organic compound is 1% by mass or more and 20% by mass or less with respect to the total mass of the sheet. The sheet according to claim 1, wherein the oxygen-containing organic compound is polyethylene oxide . The sheet according to claim 1 or 2 , wherein the fine fibrous cellulose has a phosphate group or a substituent derived from a phosphate group. The sheet according to any one of claims 1 to 3 , wherein the content of the thermoplastic resin fiber is 15% by mass or more and 45% by mass or less with respect to the total mass of the sheet. When the thermal melting point + 50 ℃ of thermoplastic resin fibers, and then the hot pressing under conditions of 10MPa to form a molded body, according to claim 1-4 in which the total light transmittance of the molded article is 70% or more The sheet according to any one of the items. In the case of forming the thermoplastic resin fibers having a melting point of + 50 ° C., and then the hot pressing under conditions of 10MPa moldings, claim 1-5 haze of the molded article is 20% or less 1 The sheet described in Section. When a molded body is formed by heat and pressure molding under the conditions of melting point + 50 ° C. and 10 MPa of the thermoplastic resin fiber, the flexural modulus at 23 ° C. and 50% relative humidity of the molded body is 7 GPa or more The sheet according to any one of claims 1 to 6 . A molded article comprising fine fibrous cellulose having a fiber width of 1,000 nm or less, a thermoplastic resin, and a non-fibrous oxygenated organic compound,
The oxygen-containing organic compound is a polyalkylene oxide,
The thermoplastic resin constituting the thermoplastic resin fiber is at least one selected from polylactic acid, polybutylene succinate, ethylene-vinyl alcohol copolymer, amorphous PET, polypropylene, acid-modified polypropylene, polycarbonate and polyethylene Yes,
The molded object whose content of the said oxygen containing organic compound is 1 mass% or more and 20 mass% or less with respect to the total mass of the said molded object. The molded article according to claim 8 , wherein the thermoplastic resin is hydrophobic. The content of the thermoplastic resin in a region from the surface of one of the molded bodies to the thickness of 1 μm from the surface containing a large amount of thermoplastic resin is C1 mass%,
When the content of the thermoplastic resin in a region in the range of ± 0.5 μm from the center plane of the molded body is C2 mass%,
The molded article according to claim 8 or 9 , wherein the value of C1 / C2 is 0.25 or more and 3 or less. The molded article according to any one of claims 8 to 10 , wherein the total light transmittance is 70% or more. The molded article according to any one of claims 8 to 11 , wherein the haze is 20% or less. The molded article according to any one of claims 8 to 12 , which has a flexural modulus of 7 GPa or more at 23 ° C and a relative humidity of 50%. A process of heating and pressing a sheet according to any one of claims 1 to 7 ;
The manufacturing method of the molded object whose shaping | molding temperature in the process of carrying out the said heat-pressing shaping | molding is melting | fusing point +/- 20 degreeC of the said thermoplastic resin. The laminated body which has a molded object and the resin layer of any one of Claims 8-13 . The laminate according to claim 15 , wherein the resin layer comprises polycarbonate. The laminate according to claim 15 or 16 , wherein the flexural modulus at 23 ° C and a relative humidity of 50% is 2.5 GPa or more, and the linear thermal expansion coefficient is 200 ppm / K or less.

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