JP2017095831A - Sheet containing cellulose fiber layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet which is excellent in resin impregnability while being a thick film as a sheet, and has improved sheet strength (elastic modulus).SOLUTION: There is provided a sheet formed of a single layer or a plurality of layers composed of three or less layers, the sheet containing at least one cellulose fiber layer containing 50 wt.% or more of a reproduced cellulose fiber, and satisfies the following requirements: (1) a fiber diameter equivalent to specific surface area of the fiber constituting the cellulose fiber layer of 0.20 μm or more and 2.0 μm or less; (2) an air transmission-resistant rate of the sheet of 1 s/100 ml or more and 400,000 s/100 ml or less; and (3) a film thickness of the sheet of exceeding 22 μm; and a composite film formed by impregnating the sheet with the (B) resin.SELECTED DRAWING: None

Description

  The present invention relates to a sheet having a network structure made of cellulose fibers, a core material for fiber-reinforced plastic film, a core material for in-vehicle use, a core material for printed wiring boards for electronic materials, a core material for insulating film, and a core The present invention relates to a core material.

In recent years, fiber reinforced plastics (FRP: Fiber Reinforced Plastics) are attracting attention in various industrial fields as lightweight and high-strength materials. Fiber reinforced composite materials consisting of glass fibers, carbon fibers, aramid fibers, etc. and matrix resins are lightweight compared to competing metals, etc., but have excellent mechanical properties such as strength and elastic modulus. It is used in many fields such as spacecraft members, automobile members, ship members, civil engineering and building materials, and sports equipment. Particularly in applications where high performance is required, carbon fibers excellent in specific strength and specific elastic modulus are often used as reinforcing fibers. In addition, thermosetting resins such as unsaturated polyester resins, vinyl ester resins, epoxy resins, phenol resins, cyanate ester resins, and bismaleimide resins are often used as matrix resins, with excellent adhesion to carbon fibers. Many epoxy resins are used. Recently, in order to produce relatively large fiber-reinforced plastic moldings at low cost, a vacuum impregnation molding method (VaTM: Vacuum assist Resin Transfer Molding) has been adopted in which fiber-reinforced plastics are molded under reduced pressure by vacuum suction. (For example, see the following Patent Document 1). On the other hand, the fiber reinforced plastic manufactured by combining the fiber and matrix resin studied in the past, because the fiber used is thick, its internal structure is clearly divided into a fiber part and a resin part. The effect of improving the mechanical properties is insufficient.
Here, since the fiber diameter for FRP generally used has a fiber diameter of a micron level, it is difficult to cause a problem in the resin impregnation property with a thick film. However, simply converting ordinary fibers into nanofibers increases the number of entanglement points per unit volume and improves the mechanical properties as FRP, but the resin impregnation (permeability) is sufficient especially in applications where thick films are required. It was not.

JP-A-60-83826

In view of the above-described state of the art, the inventors of the present invention have studied the technique for further improving the mechanical characteristics, and as a result, the surface area is increased by using nanofibers, and the thickness is reduced at the micron level. We focused on the fact that a cellulose nanofiber sheet with extremely high thermal stability can be formed by controlling the formation of a hydrogen bond network.
The problem to be solved by the present invention is to provide a sheet that is thick as a sheet but has excellent resin impregnation properties and can improve sheet strength (elastic modulus) when combined.

[1] A sheet composed of a single layer containing at least one cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers or a plurality of layers of 3 layers or less, and the following requirements:
(1) The specific surface area equivalent fiber diameter of the fibers constituting the cellulose fiber layer is 0.20 μm or more and 2.0 μm or less;
(2) The air resistance of the sheet is 1 s / 100 ml or more and 400,000 s / 100 ml or less; and (3) The thickness of the sheet is more than 22 μm;
A sheet characterized by satisfying
[2] The sheet according to [1], wherein the cellulose fiber layer contains 70% by weight or more of regenerated cellulose fibers.
[3] The sheet according to [1] or [2], wherein the air resistance is 5 s / 100 ml or more and 20,000 s / 100 ml or less.
[4] The fiber surface diameter corresponding to the specific surface area of the regenerated cellulose fiber is 0.20 μm or more and 2.0 μm or less, and the cellulose fiber layer contains fibers having a fiber diameter of 3 μm or more and 15 μm or less more than 0 wt% and 30 wt% The sheet according to any one of [1] to [3], which is included below.
[5] The sheet according to any one of [1] to [4], wherein the thickness of the sheet is more than 100 μm.
[6] The sheet according to any one of [1] to [5], wherein a fiber constituting the cellulose fiber layer has a specific surface area equivalent fiber diameter of 0.20 μm to 0.45 μm.
[7] The sheet according to any one of [1] to [6], wherein the basis weight of the cellulose fiber layer is 2 g / m ² or more.
[8] The sheet according to any one of [1] to [7], wherein the cellulose fiber layer contains natural cellulose fibers at less than 50% by weight.
[9] The sheet according to [8], wherein the cellulose fiber layer contains less than 30% by weight of natural cellulose fiber.
[10] The sheet according to any one of [1] to [7], wherein the cellulose fiber layer contains fibers made of an organic polymer other than cellulose at less than 50% by weight.
[11] The sheet according to [10], wherein the cellulose fiber layer contains less than 30% by weight of an organic polymer other than cellulose.
[12] The sheet according to [11], wherein the fiber made of an organic polymer other than cellulose is an aramid fiber and / or a polyacrylonitrile fiber.
[13] The sheet according to any one of [1] to [12], wherein the cellulose fiber layer contains a reactive crosslinking agent at 10% by weight or less.
[14] one layer of the multilayer structure of more than the three layers having a basis weight including the base layer is a nonwoven fabric or paper is 5 g / ^{m 2} or more 200 g / ^{m 2} or less, any of [1] to [13] Crab sheet.
[15] and further with a multi-layer structure of more than the three-layer, sheet according to basis weight comprises a substrate layer is a nonwoven fabric or paper is 10 g / ^{m 2} or more 100 g / ^{m 2} or less, wherein [14].
[16] The method for producing a sheet according to any one of [1] to [15], including an aqueous papermaking process.
[17] The method for producing a sheet according to any one of [1] to [15], including a coating step.
[18] The sheet according to any one of [1] to [15], which is used for sound insulation.
[19] (A) A composite film in which the sheet according to any one of [1] to [15] is impregnated with (B) resin.
[20] The composite film according to [19], wherein the (B) resin is one or more resins selected from the group consisting of a thermoset resin, a photocured resin, and a thermoplastic resin.
[21] The composite film according to [19] or [20], wherein the (B) resin is one or more of an epoxy resin, an acrylic resin, and a general-purpose plastic.
[22] The composite film according to any one of [19] to [21], wherein the (B) resin contains less than 50% by mass of inorganic fine particles.
[23] The composite film according to [22], wherein the inorganic fine particles are one or more selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , MgO, ZnO, and BaTiO _3. .
[24] A composite prepreg film comprising (A) the sheet according to any one of [1] to [15], and (B) a thermosetting resin and / or a photocurable resin.
[25] The composite prepreg film according to [24], wherein the (B) resin is an epoxy resin, an acrylic resin, and / or a polyimide resin.
[26] The composite prepreg film according to [24] or [25], wherein the (B) resin contains inorganic fine particles in an amount of less than 50% by mass.
[27] The composite prepreg according to [26], wherein the inorganic fine particles are one or more selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , MgO, ZnO, and BaTiO _3. the film.
[28] A fiber reinforced plastic film core material comprising the sheet according to any one of [1] to [15].
[29] The fiber reinforced plastic film core material according to [28], for use in a vehicle-mounted material.
[30] The core material for fiber-reinforced plastic film according to [28], for an electronic material.
[31] A prepreg for fiber-reinforced plastic film comprising the sheet according to any one of [1] to [15].
[32] A fiber-reinforced plastic film including the sheet according to any one of [1] to [15].
[33] The fiber reinforced plastic film according to the above [32] for in-vehicle materials.

  The sheet of the present invention is excellent in resin impregnation because it has a limited air permeability resistance range, that is, a pore diameter, although it is a thick film. Therefore, for example, when used as a core material for fiber reinforced plastic, thermal stability (reduction of linear thermal expansion coefficient and elastic retention at high temperature) can be imparted when combined with a resin. Further, when used as a core material for in-vehicle materials, it is possible to ensure mechanical characteristics when combined while being lightweight as in-vehicle materials.

Hereinafter, embodiments of the present invention will be described in detail.
In this embodiment, by using regenerated cellulose as a raw material, cellulose nanofibers having a predetermined range of fiber diameters can be provided by miniaturization. The sheet thus produced is thick as a sheet and has a limited air permeability resistance range, that is, a pore diameter, and therefore has excellent resin impregnation properties. Therefore, for example, when used as a core material for fiber-reinforced plastic, thermal stability (reduction of linear thermal expansion coefficient or retention of elastic modulus) can be imparted when it is combined with a resin. Further, when used as a core material for in-vehicle materials, the sheet strength can be ensured even though the in-vehicle materials are thin.
Since the regenerated cellulose fiber contained in the sheet of the present invention has a specific range of fiber diameters and maintains constant pores, and there are many entanglement points between the fibers, the strength is increased even when the film is thickened. While maintaining, it is excellent in resin impregnation property and has a characteristic that flatness is expressed even if a large number of layers are laminated because the fiber diameter is small.

The sheet of this embodiment is a sheet composed of a single layer including at least one cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers, or a plurality of layers of 3 or less layers, and the following requirements:
(1) The specific surface area equivalent fiber diameter of the fibers constituting the cellulose fiber layer is 0.20 μm or more and 2.0 μm or less;
(2) Air permeability resistance is 1 s / 100 ml or more and 400,000 s / 100 ml or less; and (3) Film thickness is more than 22 μm;
It is a sheet that satisfies Such a sheet can be suitably used as a core material for a fiber-reinforced plastic film.
The reason will be described below.

  For example, in the field of fiber reinforced plastic films, particularly in the field of in-vehicle and aircraft materials, there is a great need for lighter substrates and higher elastic modulus. It can be a core material for a fiber-reinforced plastic film, which is a material required in the application field, is lightweight, has excellent suitability in processing steps such as resin impregnation, and has high thermal stability.

Hereinafter, the sheet of this embodiment will be described in detail.
First, the cellulose fiber which comprises the sheet | seat of this embodiment is demonstrated.
In the present embodiment, the regenerated cellulose is a substance obtained by regenerating natural cellulose by dissolving or crystal swelling (mercelization) treatment, and the lattice spacing of 0.73 nm, 0.44 nm and 0. A β-1,4-bonded glucan (glucose polymer) having a molecular arrangement that gives a crystal diffraction pattern (cellulose type II crystal) having a diffraction angle corresponding to 40 nm as a vertex. In the X-ray diffraction pattern, an X-ray diffraction pattern in which the range of 2θ ranges from 0 ° to 30 ° includes one peak at 10 ° ≦ 2θ <19 °, and two peaks at 19 ° ≦ 2θ ≦ 30 °. For example, it means regenerated cellulose fibers such as rayon, cupra and tencel. Among these, from the viewpoint of ease of miniaturization, it is preferable to use a fiber refined using cupra or tencel having a high molecular orientation in the fiber axis direction as a raw material.

  The maximum fiber thickness of the regenerated cellulose fiber is preferably 15 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, and most preferably 3 μm or less. Here, the maximum fiber thickness of 15 μm or less means that no fibers exceeding a fiber diameter of 15 μm can be confirmed on the image in an electron microscope (SEM) of a cellulose nonwoven fabric measured under the following conditions. . A surface SEM image of the separator was collected at a magnification equivalent to 10,000 times, and the fiber diameter was 15 μm or less for any entangled fibers contained in this image, and any part of the cast surface was similarly subjected to the same conditions. When a fiber exceeding a fiber diameter of 15 μm cannot be confirmed in the same manner for a total of 100 or more fibers, the maximum fiber diameter is defined as 15 μm or less. However, when it can be clearly confirmed that several fibers are bundled and have a fiber diameter of 15 μm or more in the image, it is not considered as a fiber having a fiber diameter of 15 μm or more. When regenerated cellulose long fibers having a maximum fiber diameter of 3 μm or more and 15 μm or less are mixed with regenerated cellulose fibers, or when regenerated cellulose having a maximum fiber diameter of 3 μm or more and 15 μm or less remains after refining, a resin for a thick film sheet It is preferable because of its excellent impregnation property, and its content is preferably more than 0% by weight and 30% by weight or less.

As the sheet of this embodiment, among celluloses containing 50% by weight or more of regenerated cellulose fibers, the fiber layer has a specific surface area equivalent fiber diameter of 2.0 μm or less, preferably 1.0 μm or less, more preferably 0.45 μm or less. More preferably, it is 0.40 μm or less. Here, the specific surface area equivalent fiber diameter will be described. The specific surface area is first evaluated using the BET method by nitrogen adsorption, and the fibers constituting the separator are virtually in an ideal state in which no fusion between the fibers occurs with respect to the specific surface area, and the cellulose density is By a cylindrical model assuming that the surface is constituted by fibers that are infinite cylinders with d (g / cm ³ ) and L / D (L: fiber length, D: fiber diameter (both units: μm)). The following formula for specific surface area and fiber diameter:
Specific surface area = 4 / (dD) (m ² / g)
Induced. The specific surface area by the BET method is substituted as the specific surface area of the above formula, and the numerical value converted to the fiber diameter D by substituting d = 1.50 g / cm ³ as the cellulose density is defined as the specific surface area equivalent fiber diameter. Here, the specific surface area measurement by the BET method is performed by measuring the adsorption amount of nitrogen gas at the boiling point of liquid nitrogen with respect to about 0.2 g of sample with a specific surface area / pore distribution measuring device (manufactured by Beckman Coulter). Then, the specific surface area was calculated.

  The sheet of this embodiment can suitably provide a sheet having a uniform thickness distribution by selecting the fiber diameter corresponding to the specific surface area of the cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers within the above range. When the fiber diameter corresponding to the specific surface area of the cellulose fiber layer containing 50% by weight or more of the regenerated cellulose fiber exceeds 2.0 μm, the fiber diameter is too large, and thus the above-described irregularities on the surface of the fiber sheet are generated, resulting in a distribution of the microporous structure. Since it becomes large, that is, holes with large pore diameters are scattered, it becomes impossible to provide a thin and excellent sheet. Moreover, when using the sheet | seat of this embodiment as a separator, when the fiber diameter equivalent to a specific surface area of a cellulose fiber layer exceeds 2.0 micrometers, it is unpreferable from a point of short-circuit resistance.

  The fiber diameter corresponding to the specific surface area of the cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers as the sheet of this embodiment is 0.20 μm or more, preferably 0.25 μm or more. If the fiber diameter corresponding to the specific surface area of the cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers is less than 0.20 μm, the pore diameter of the fiber sheet becomes too small. Therefore, when the sheet and resin are combined in fiber-reinforced plastic applications, the resin is not impregnated, and the fiber diameter is too thin, which causes deterioration of the fiber-reinforced plastic, resulting in increased internal resistance over time and gas generation. Since it may be connected, it is not preferable. In addition, when a sheet is produced in a paper making process, which will be described later, fibers are lost, which is not preferable because the yield decreases.

  As the sheet of this embodiment, the regenerated cellulose fiber contains 50% by weight or more. Preferably it is 70 weight% or more, More preferably, it is 80 weight% or more. By using a fiber containing 50% by weight or more of regenerated cellulose, when a sheet is formed by a papermaking method or a coating method using a cellulose nanofiber slurry in water, the shrinkage of the fiber layer is suppressed during drying, It is possible to maintain the pores and hole diameters. Therefore, when the sheet and resin are combined in fiber-reinforced plastics, the resin is easily impregnated and easily combined, and the number of entanglement points of the regenerated cellulose fiber is larger than that of a normal cellulose fiber sheet. The thermal stability (reduction of the coefficient of linear thermal expansion, elasticity retention at high temperatures) when combined with can be improved.

The sheet according to the present embodiment is characterized in that the air permeability resistance is in the range of 1 s / 100 cc to 400,000 s / 100 cc, preferably 100,000 s / 100 cc, more preferably 20,000 s / 100 cc. . Here, the air resistance is a numerical value measured based on the Gurley tester method described in JIS P 8117. More preferably, the air resistance is 2 s / 100 cc to 10,000 s / 100 cc, more preferably 5 s / 100 cc to 100 s / 100 cc, and most preferably 8 s / 100 cc to 100 s / 100 cc. . In a sheet having an air permeability resistance lower than 1 s / 100 cc, it is difficult to produce the sheet uniformly without defects even though it is composed of fine fibers. In addition, the fiber reinforced plastic is not preferable because it has a problem of strength and does not exhibit functions in various applications. On the other hand, when it exceeds 400,000 s / 100 cc, the porosity decreases or the pore diameter becomes too small. Therefore, when the sheet of the present invention is used as a fiber-reinforced plastic, the sheet is not impregnated with resin, and the composite is incomplete, and the thermal stability of the composite film that should be originally expressed (reduction in linear thermal expansion coefficient or Loss of elasticity at high temperatures).
Further, if the air permeability resistance is 5,000 s / 100 cc or less, it is preferable because the resin is easily impregnated when the sheet and the resin are combined in a fiber-reinforced plastic application.

The sheet of this embodiment can be obtained by processing cellulose fibers into a sheet as described above, but the substantial film thickness is larger than 22 μm. Here, the film thickness is measured by using a surface contact type film thickness meter such as a Mitutoyo film thickness meter (Model ID-C112XB) or the like, and cutting out 10.0 cm × 10.0 cm square pieces at various positions. The average value of the five measured values is defined as film thickness T (μm). Further, from the film thickness T (μm) of the 10.0 cm × 10.0 cm square piece cut out by the measurement of the film thickness and its weight W (g), the following formula:
W0 = 100 × W
Can be used to calculate the basis weight W0 (g / m ² ) of the film.

The sheet of the present embodiment is more preferably 100 μm or more and 10 mm or less. When the film thickness is in the above range, resin impregnation property, strength (elastic modulus), and thermal stability can be imparted while maintaining flatness when a composite film is produced using a sheet. If the thickness is 22 μm or less, the strength (elastic modulus) and thermal stability during resin impregnation may be inferior.
In addition, the thickness of the fine cellulose layer itself is preferably 20 μm or more from the viewpoint of strength, and more preferably 50 μm or more.

The basis weight of the cellulose fiber layer used in the sheet of this embodiment is 1 g / m ² or more, preferably 2 g / m ² or more and 1000 g / m ² or less, more preferably 3 g / m ² or more and 500 g / m ² or less, More preferably, it is 4 g / m ² or more and 100 g / m ² or less. When the basis weight is less than 1 g / m ^2, it is difficult to handle in the assembly process to various devices and may be inappropriate, which is not preferable from the viewpoint of long-term stability. The upper limit of the basis weight is not limited as long as there is no problem in the impregnation property of the resin, but is preferably 1000 g / m ² or less from the viewpoint of production.

  The cellulose fiber layer containing 50% by weight or more of the regenerated cellulose fiber used in the sheet of this embodiment may further contain natural cellulose fiber in an amount of less than 50% by weight in addition to the regenerated cellulose fiber. By using natural cellulose fibers, it is possible to relatively easily produce fine cellulose fibers having a fiber diameter of less than 0.20 μm from the fineness of the microfibril as the structural unit, and the finer fiber length / fiber. By mixing natural cellulose fibers having a large diameter ratio, the strength of the sheet can be increased. By containing less than 50% by weight of natural cellulose fiber, the strength of the cellulose fiber layer is increased, and the handleability and linear thermal expansion coefficient (CTE) when assembling the device are extremely good. The content is more preferably less than 30% by weight.

As for the natural cellulose fiber diameter in the cellulose fiber layer used for the sheet of the present embodiment, the maximum fiber thickness is preferably 15 μm or less. When the maximum fiber diameter is 15 μm or less, it is preferable from the viewpoint of the surface flatness of the sheet.
Natural cellulose fibers whose maximum fiber diameter does not exceed 15 μm include wood pulp obtained from broad-leaved trees or conifers, refined linters, or refined pulps from various plant species (bamboo, hemp fiber, bagasse, kenaf, linter, etc.), etc. In addition to those obtained by highly advanced treatment, natural cellulose fibers that are aggregates of never-dry and fine fibers such as bacterial cellulose (BC) produced by cellulose-producing bacteria (bacteria) are also included.

  Further, the cellulose fiber layer used in the sheet of the present embodiment and containing 50% by weight or more of regenerated cellulose fiber further contains less than 50% by weight of fibers made of an organic polymer other than cellulose in addition to the regenerated cellulose fiber. More preferably, it is 30 wt% or less. As the organic polymer, any organic polymer capable of producing fibers can be used. For example, aromatic or aliphatic polyester, nylon, polyacrylonitrile, cellulose acetate, polyurethane, polyethylene, polypropylene, polyketone, aromatic Examples include natural organic polymers other than cellulose, such as group polyamide, polyimide, silk, and wool, but are not limited thereto. The fibers made of the organic polymer are fibers obtained by beating organic fibers, finely fibrillated or miniaturized by a high-pressure homogenizer, etc., fibers obtained by electrospinning using various polymers as raw materials, and various polymers as raw materials. Although the fiber etc. which are obtained by the melt blown method can be mentioned, it is not limited to these. Among these, a microfibrous aramid obtained by refining an aramid fiber, which is a polyacrylonitrile nanofiber or wholly aromatic polyamide, with a high-pressure homogenizer is particularly suitable for use due to the high heat resistance and high chemical stability of the aramid fiber. be able to. As for the fiber diameter of these organic polymers, the maximum fiber thickness is preferably 15 μm or less.

Next, the manufacturing method of a cellulose fiber is described.
The refining of the cellulose fiber is preferably performed through a pretreatment step, a beating treatment step, and a refining step for both the regenerated cellulose fiber and the natural cellulose fiber. In particular, when regenerated cellulose fibers are refined, the pretreatment step can be carried out in a water washing step using a surfactant to remove the oil agent, but in the pretreatment step of natural cellulose fibers, It is effective to make the raw material pulp easy to be refined in the subsequent steps by autoclave treatment under an impregnation in water at a temperature of 150 ° C., enzyme treatment, or a combination thereof. In the pretreatment step, an inorganic acid (hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, etc.) or an organic acid (acetic acid, citric acid, etc.) having a concentration of 1% by weight or less may be added for autoclaving. Some are effective. These pretreatments not only reduce the load of the micronization process, but also discharge impurity components such as lignin and hemicellulose present on the surface and gaps of the microfibrils that make up the cellulose fibers to the aqueous phase, resulting in a finer process. Since there is also an effect of increasing the α-cellulose purity of the formed fiber, it may be very effective in improving the heat resistance of the cellulose fiber nonwoven fabric.
After the beating process, both regenerated cellulose fiber and natural cellulose fiber are produced with the following contents. In the beating treatment step, the raw material pulp is 0.5 wt% or more and 4 wt% or less, preferably 0.8 wt% or more and 3 wt% or less, more preferably 1.0 wt% or more and 2.5 wt% or less. Disperse in water to a partial concentration and thoroughly promote fibrillation with a beating device such as a beater or disc refiner (double disc refiner). When a disc refiner is used, if the clearance between the discs is set as narrow as possible (for example, 0.1 mm or less) and processing is performed, extremely advanced beating (fibrillation) proceeds, so a high-pressure homogenizer or the like is used. The conditions for the miniaturization treatment can be relaxed and may be effective.

In the production of the cellulose fiber, it is preferable to carry out a refining treatment with a high-pressure homogenizer, an ultrahigh-pressure homogenizer, a grinder, etc. following the above-described beating step. In this case, the solid content concentration in the aqueous dispersion is 0.5 wt% or more and 4 wt% or less, preferably 0.8 wt% or more and 3 wt% or less, more preferably 1.0 wt. % By weight to 2.5% by weight. In the case of a solid content concentration in this range, clogging does not occur and an efficient miniaturization process can be achieved.
Examples of the high-pressure homogenizer used include NS type high-pressure homogenizer manufactured by Niro Soabi (Italy), SMT's Lanier type (R model) pressure-type homogenizer, and Sanwa Kikai Co., Ltd. high-pressure type homogenizer. Any device other than these devices may be used as long as the device performs miniaturization by a mechanism substantially similar to those of these devices. Ultra-high pressure homogenizers mean high-pressure collision type miniaturization machines such as Mizuho Kogyo Co., Ltd. microfluidizer, Yoshida Kikai Kogyo Co., Ltd. Nanomizer, Sugino Machine Ultimate Co., Ltd. Any device other than these devices may be used as long as the device performs miniaturization with a substantially similar mechanism. Examples of the grinder-type miniaturization device include the pure fine mill of Kurita Machinery Co., Ltd. and the stone mill type milling die represented by Masuyuki Sangyo Co., Ltd. Any device other than these may be used as long as the device performs miniaturization by this mechanism.

The fiber diameter of the fine cellulose fiber is determined according to the conditions for refinement using a high-pressure homogenizer (selection of equipment and operating pressure and number of passes) or pre-treatment conditions (for example, autoclave treatment, enzyme treatment, beating treatment). Etc.).
Furthermore, as the natural cellulose fine fiber, the cellulose fine fiber to which the chemical treatment of the surface is added, and the cellulose type in which the hydroxyl group at the 6-position is oxidized by the TEMPO oxidation catalyst to become a carboxyl group (including acid type and salt type). It is also possible to use fine fibers. In the former case, by subjecting to various surface chemical treatments according to the purpose, for example, some or most of the hydroxyl groups present on the surface of the fine cellulose fiber are esterified including acetate ester, nitrate ester, sulfate ester. In addition, etherified products including alkyl ethers typified by methyl ether, carboxy ethers typified by carboxymethyl ether, and cyanoethyl ether can be appropriately prepared and used. Moreover, in the preparation of the latter, that is, the fine cellulose fiber in which the hydroxyl group at the 6-position is oxidized by the TEMPO oxidation catalyst, it is not always necessary to use a high-energy refining device such as a high-pressure homogenizer. A dispersion can be obtained. For example, as described in the literature (A. Isogai et al., Biomacromolecules, 7, 1687-1691 (2006)), 2,2,6,6-tetramethylpiperidinooxy is added to an aqueous dispersion of natural cellulose. By mixing a catalyst called TEMPO such as a radical with an alkyl halide, adding an oxidant such as hypochlorous acid to this, and allowing the reaction to proceed for a certain period of time, after a purification treatment such as water washing, an ordinary mixer By performing the treatment, a dispersion of fine cellulose fibers can be obtained very easily.

  In the present embodiment, the above-mentioned regenerated cellulose or natural cellulose fine fibers with different raw materials, natural cellulose fine fibers with different degrees of fibrillation, natural cellulose fine fibers whose surfaces are chemically treated, organic polymer fine fibers It may be effective to form a cellulose fine fiber layer by mixing a predetermined amount of two or more of the above.

The cellulose fiber layer used in the sheet of the present embodiment is effective for reinforcing the strength even if it contains 10% by weight or less of a reactive crosslinking agent. The reactive crosslinking agent refers to a reactant derived from a polyfunctional isocyanate, and refers to a resin produced by an addition reaction between a polyfunctional isocyanate compound and an active hydrogen-containing compound. By containing 10% by weight or less of the reactive cross-linking agent, the strength of the cellulose fine fiber layer is increased, and the sheet becomes very good in handling when assembling the device. More preferably, it is 6% by weight or less.
Examples of the reactive crosslinking agent polyfunctional isocyanate compound that forms the reactive crosslinking agent in the cellulose fiber layer used in the sheet of the present embodiment include aromatic polyfunctional isocyanate, araliphatic polyfunctional isocyanate, Examples thereof include alicyclic polyfunctional isocyanate and aliphatic polyfunctional isocyanate. From the viewpoint of less yellowing, alicyclic polyfunctional isocyanates and aliphatic polyfunctional isocyanates are more preferable. Moreover, the polyfunctional isocyanate compound may be contained 1 type, or 2 or more types.

Examples of the aromatic polyfunctional isocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and a mixture thereof (TDI), diphenylmethane-4,4′-diisocyanate (MDI), and naphthalene-1,5. -Aromatic polyfunctional isocyanates such as diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, crude TDI, polymethylene polyphenyl diisocyanate, crude MDI, phenylene diisocyanate and xylylene diisocyanate.
Examples of the alicyclic polyfunctional isocyanate include alicyclic polyfunctional isocyanates such as 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, and cyclohexane diisocyanate.
Examples of the aliphatic polyfunctional isocyanate include aliphatic polyfunctional isocyanates such as trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate, pentamethylene diisocyanate, and hexamethylene diisocyanate.
Examples of the active hydrogen-containing compound include a hydroxyl group-containing compound including a monohydric alcohol, a polyhydric alcohol, and phenols, an amino group-containing compound, a thiol group-containing compound, and a carboxyl group-containing compound. Also included are water and carbon dioxide present in the air or in the reaction field. One or more active hydrogen-containing compounds may be contained.

Examples of the monohydric alcohol include alkanols having 1 to 20 carbon atoms (methanol, ethanol, butanol, octanol, decanol, dodecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, etc.), and alkenols having 2 to 20 carbon atoms (oleyl alcohol). And linoleyl alcohol) and araliphatic alcohols having 7 to 20 carbon atoms (such as benzyl alcohol and naphthylethanol).
Examples of the polyhydric alcohol include divalent alcohols having 2 to 20 carbon atoms [aliphatic diols (ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol). And 1,10-decanediol, etc.), alicyclic diols (cyclohexanediol, cyclohexanedimethanol, etc.) and araliphatic diols {1,4-bis (hydroxyethyl) benzene, etc.}, etc.], carbon number 3-20 Trihydric alcohols [aliphatic triols (such as glycerin and trimethylolpropane)] and 4- to 8-valent alcohols having 5 to 20 carbon atoms [aliphatic polyols (pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin and dipentaerythritol) Etc.) and sugars (sucrose, guru) Over scan, mannose, fructose, methyl glucoside and derivatives thereof)], and the like.

Examples of the phenols include monovalent phenols (phenol, 1-hydroxynaphthalene, anthrol, 1-hydroxypyrene, etc.), polyhydric phenols (phloroglucin, pyrogallol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1,3,6,8-tetrahydroxynaphthalene, 1,4,5,8-tetrahydroxyanthracene, a condensate of phenol and formaldehyde (novolak), a polyphenol described in US Pat. No. 3,265,641] and the like It is done.
Examples of the amino group-containing compound include monohydrocarbylamines having 1 to 20 carbon atoms [alkylamine (butylamine and the like), benzylamine and aniline and the like], aliphatic polyamines having 2 to 20 carbon atoms (ethylenediamine, hexamethylenediamine and the like). Diethylenetriamine, etc.), C6-C20 alicyclic polyamines (diaminocyclohexane, dicyclohexylmethanediamine, isophoronediamine, etc.), C2-C20 aromatic polyamines (phenylenediamine, tolylenediamine, diphenylmethanediamine, etc.), carbon Heterocyclic polyamines of 2 to 20 (such as piperazine and N-aminoethylpiperazine), alkanolamines (such as monoethanolamine, diethanolamine and triethanolamine), dicarboxylic acid and excess poly Polyamide polyamine, polyether polyamine, hydrazine (such as hydrazine and monoalkyl hydrazine), dihydrazide (such as succinic acid dihydrazide and terephthalic acid dihydrazide), guanidine (such as butyl guanidine and 1-cyanoguanidine) and dicyandiamide obtained by condensation with amine Is mentioned.

Examples of the thiol group-containing compound include monovalent thiol compounds having 1 to 20 carbon atoms (alkyl thiol such as ethyl thiol, phenyl thiol and benzyl thiol), and polyvalent thiol compounds (ethylene dithiol and 1,6-hexanedithiol). Etc.).
Examples of the carboxyl group-containing compound include monovalent carboxylic acid compounds (alkyl carboxylic acids such as acetic acid, aromatic carboxylic acids such as benzoic acid), polyvalent carboxylic acid compounds (alkyl dicarboxylic acids such as oxalic acid and malonic acid, and terephthalic acid. Aromatic dicarboxylic acids such as acids) and the like.

The cellulose fiber layer used in the sheet of this embodiment, one layer of the multilayer structure of the following three layers basis weight 2 g / ^{m 2} or more 200 g / ^{m 2} or less, preferably 5 g / ^{m 2} or more 100 g / ^{m 2} or less It may contain a base material layer which is a certain nonwoven fabric or paper. By including a base material layer that is a nonwoven fabric or paper having a basis weight of 3 g / m ² or more and 200 g / m ² or less, the base material layer supplements the strength even if the strength of the thin cellulose fiber layer itself is insufficient. For this reason, it becomes a sheet with extremely good handleability in producing members and parts while maintaining the function as a sheet.

  Examples of the base material layer used in the sheet of the present embodiment include polyamide fibers such as 6-nylon and 6,6-nylon, polyester fibers such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate, polyethylene fibers, and polypropylene. Nonwoven fabric or paper comprising at least one selected from the group consisting of fibers, natural cellulose fibers such as wood pulp and cotton linter, regenerated cellulose fibers such as viscose rayon and copper ammonia rayon, and purified cellulose fibers such as lyocell and tencel. From the viewpoint of the impregnation property of the electrolytic solution and the resin to be combined, cellulose, nylon, and polypropylene are preferable. Moreover, the said base material layer can be conveniently used from the film thickness range prescribed | regulated by this invention if it is a meltblown or electrospinning type nonwoven fabric.

  In the sheet of this embodiment, an insulating porous film may be formed on one side or both sides. In particular, when using the sheet as a separator for an electricity storage device, if the heat storage device causes local heat generation inside the battery due to an internal short circuit or the like, the separator around the heat generation site contracts and the internal short circuit further expands. Runaway fever may lead to serious events such as ignition and rupture. By providing a laminated structure in which an insulating porous film is formed on one or both sides of a sheet, it is possible to prevent the occurrence or expansion of a short circuit and provide a highly safe power storage device.

  The insulating porous film formed on the one or both sides of the laminated film of the present embodiment is made of an inorganic filler and a thermosetting resin, and the thermosetting resin does not embed the inorganic filler, and voids between the inorganic fillers are formed. It is preferable to hold. Examples of the inorganic filler include calcium oxide, sodium carbonate, alumina, gibbsite, boehmite, magnesium oxide, magnesium hydroxide, silica, titanium oxide, barium titanate, zirconium oxide, and other inorganic oxides, inorganic hydroxides, and aluminum nitride. Or at least one selected from the group consisting of inorganic nitrides such as calcium nitride, calcium fluoride, barium fluoride, barium sulfate, silicon, aluminum compounds, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, and montmorillonite .

  Examples of the thermosetting resin used in the present embodiment include an epoxy resin, an acrylic resin, an oxetane resin, an unsaturated polyester resin, an alkyd resin, a novolac resin, a resole resin, a urea resin, and a melamine. System resin etc. are mentioned, These can also be used independently and can also use 2 or more types together. These thermosetting resins are preferably water dispersions in terms of ease of handling and safety. The aqueous dispersion may contain a dispersant, an emulsifier, an organic solvent and the like as necessary. Examples of the epoxy resin include copolymers such as glycidyl acrylate, acrylic acid, methyl methacrylate, methacrylic acid, butyl methacrylate, and styrene. Examples of the acrylic resin include copolymers such as methyl methacrylate, butyl acrylate, methacrylic acid, hydroxyethyl methacrylate, and styrene.

The insulating porous film formed on the sheet of this embodiment on one side or both sides is prepared by bringing a mixed slurry of an inorganic filler and a thermosetting resin into contact with a nonwoven fabric substrate and drying it, and is fixed to the cellulose fiber layer. . You may add a thickener, an antifoamer, and an organic solvent to a mixing slurry as needed.
The insulating porous film on one or both sides formed in the laminated film of the present embodiment preferably has a basis weight of 2 g / m ² or more and 10 g / m ² or less. If the basis weight is 2 g / m ² , pinholes may be generated. On the other hand, if the basis weight is greater than 10 g / m ² , the insulating layer becomes too thick and the internal resistance increases, Powder fall and peeling may occur. The content of the inorganic filler in the laminated sheet is preferably 15.0 to 50.0% by weight. The solid content of the thermosetting resin in the separator is more preferably 1.0 to 15.0% by weight. If the content of the inorganic filler is less than 10.0% by weight and the solid content of the thermosetting resin is more than 20.0% by weight, pinholes may be generated. If the content of the inorganic filler is more than 70.0% by weight and the solid content of the thermosetting resin is less than 0.1% by weight, the inorganic filler may fall off or peel off.

  Furthermore, in the sheet of the present embodiment, the chlorine ion-containing concentration that is one measure of the amount of contained metal ions is preferably 40 ppm or less depending on the application. When the chlorine ion-containing concentration is 40 ppm or less, metal ions such as Na and Ca are also contained at a relatively low concentration. As a result, for example, the heat resistance of the separator and the electricity of the electricity storage device incorporating the separator are included. This is because the inhibition of characteristics can be suppressed. More preferably, the heat resistance is more suitably developed when the content is 30 ppm or less, and most preferably 25 ppm or less. The chloride ion concentration can be evaluated by ion chromatography.

As a main production method of the sheet of the present embodiment, a dispersion liquid in which regenerated cellulose fibers are highly dispersed in a dispersion medium such as water is formed by a papermaking method or a coating method. From the viewpoint of the efficiency of the method, it is preferable to form a film by a papermaking method. Conventionally, in order to produce a sheet having a high porosity from cellulose fibers as in the present invention, water in wet paper formed by papermaking is used to suppress fusion and aggregation between fibers during drying. It was necessary to dry after replacing with an organic solvent, or to use a dispersion containing the organic solvent as a coating solution for coating (see, for example, Japanese Patent No. 4753874). However, in the present embodiment, by containing a predetermined amount of regenerated cellulose fiber having a specific surface area equivalent diameter of 0.20 μm or more and 2.0 μm or less, the empty space required as a sheet by a papermaking method or a coating method without using an organic solvent. It has been found that the pores can be retained during drying. Here, the regenerated cellulose fiber having a specific surface area equivalent diameter of 0.20 μm or more and 2.0 μm or less is a single-layer papermaking (weight per unit: 10 g / m ² ) from an aqueous dispersion containing only the corresponding regenerated cellulose fiber. It means a regenerated cellulose fiber having a specific surface area equivalent fiber diameter of 0.20 μm or more and 2.0 μm or less calculated from the specific surface area measurement by the BET method of the single layer sheet obtained when the film is formed. The fiber diameter corresponding to the specific surface area is preferably 0.25 μm or more. The fiber diameter corresponding to the specific surface area is preferably 1.0 μm or less, more preferably 0.45 μm or less, and most preferably 0.40 μm or less. When the fiber diameter corresponding to the specific surface area is smaller than 0.20 μm, it becomes difficult to maintain pores suitable for the sheet of the present invention from drying from the aqueous wet paper, and the fiber diameter corresponding to the specific surface area is more than 2.0 μm. As the value increases, a problem that thinning and uniformity cannot be achieved easily occurs.

When manufacturing the sheet of the present embodiment, the dispersion method when the cellulose fibers are highly dispersed as an aqueous dispersion for papermaking or coating is also important, and the selection is made with a uniform sheet thickness to be described later. It greatly affects sex.
In order to prepare the separator of this embodiment, the dispersion containing the regenerated cellulose fiber obtained by the fibrillation treatment or the refinement treatment by the above-described production method is diluted as it is or diluted with water and dispersed by an appropriate dispersion treatment. A dispersion for papermaking or coating. Components other than regenerated cellulose fibers, such as natural cellulose fibers, fibers made of organic polymers other than cellulose, or reactive cross-linking agents, etc. may be mixed at any timing in each step of the above-described dispersion production, It may be desirable to add it at the stage of producing the dispersion for coating. The components are mixed and then dispersed by an appropriate dispersion treatment to obtain a dispersion for papermaking or coating. Regarding the timing of mixing fibers other than the regenerated cellulose fiber in particular, it may be mixed with the regenerated cellulose raw material (cut yarn) in the beating process from the pulp or cut yarn stage, and may be beaten. You may mix in the process of performing the refinement | miniaturization process by. Any dilution method may be used for dilution after the dispersion for papermaking or coating, or after mixing the raw materials, but it is appropriately selected according to the contents of the mixed raw material components. For example, a disper-type stirrer, various homomixers, various line mixers and the like can be mentioned, but the invention is not limited to these.

Hereinafter, the film forming method mainly by the papermaking method will be described.
The paper making method can be carried out using not only a batch type paper machine but also all industrially available continuous paper machines. In particular, the composite sheet material of the present embodiment can be suitably produced by an inclined wire type paper machine, a long net type paper machine, and a round net type paper machine. In order to improve film quality uniformity, use one or more machines (for example, an inclined wire type paper machine is used for the base layer paper and a round net type paper machine is used for the upper layer paper machine). It is also effective in some cases. The papermaking multistage, for example, by performing carried out papermaking with a basis weight of 5 g / m ² in the first stage, the thus obtained wet the second stage of the paper of 5 g / m ² on paper, total 10 g / m ² This is a technique for obtaining the composite sheet material of the present invention having a basis weight of. In the case of multi-stage papermaking, when the upper layer and the lower layer are formed from the same dispersion, the composite sheet material of the present invention is a single layer, but the first layer as the lower layer uses fine fibers using, for example, fibrillated fibers. It is also possible to form a wet paper layer and then make paper with the above-described dispersion in the second stage, and allow the lower wet paper to function as a filter to be described later.

Since the sheet of this embodiment uses fine fibers, it is preferable to use a filter cloth or a plastic wire having a fine structure in which the fine fibers do not come out during paper making when forming a film by a paper making method. As a filter cloth or plastic wire having such a fine structure, basically, the solid content in the dispersion for papermaking stops as wet paper, that is, 90% by weight as the solid content yield in the papermaking process. As described above, industrially suitable production is possible by selecting a filter cloth or plastic wire that is preferably 95% by weight or more, more preferably 99% by weight or more. A high yield also means that the bite into the filter is low, which is preferable in that the peelability after papermaking becomes good. In addition, it is desirable to reduce the filter mesh size because the yield is improved. However, if the filterability is deteriorated, it is not preferable because the production rate of wet paper is reduced. That is, the water permeation amount of wire mesh or cloth under 25 ° C. atmospheric pressure, is preferably 0.005ml / cm ² · s or more, more preferably 0.01ml / cm ² · s or more, productivity From this point of view, it is possible to make a suitable paper. In practice, it is preferable to select a filter cloth or plastic wire having a high solid content and good drainage. Although the filter cloth and plastic wire which satisfy | fill said conditions are limited, For example, TETEXMONODW07-8435-SK010 (product made from PET) made by SEFAR (Switzerland), NT20 (PET / nylon blend) made by Shikishima canvas company as a filter cloth, Examples thereof include, but are not limited to, plastic wire LTT-9FE manufactured by Nippon Filcon Co., Ltd. and multilayered wires described in JP2011-42903A.

  On a filter cloth satisfying the above-described conditions, a dispersion for papermaking prepared with a cellulose fiber concentration of 0.01% to 0.5% by weight, more preferably 0.05% to 0.3% by weight The wet paper having a solid content of 4% by weight or more of the cellulose fiber can be produced by depositing on the filter cloth by filtering with a suction operation or the like. The solid content in this case is preferably as high as possible, preferably 8% by weight or more, and more preferably 12% by weight or more. In general, by further pressing the wet paper, the dispersion medium in the papermaking dispersion can be removed with high efficiency, and the solid content in the resulting wet film can be increased. It becomes possible to obtain a wet paper with high strength. However, when a relatively thick film sheet is obtained, it is preferable not to perform the press treatment because a thick film with a low defect, a large pore diameter, and a high strength can be obtained. Further, a sheet with high flatness can be obtained without pressing, which is preferable from the viewpoint of productivity. After that, a drying process is performed by a drying facility such as a drum dryer, and the sheet is wound up as a sheet. In the drying step, the separator of the present invention can be obtained by drying the wet paper. Drying is usually performed under atmospheric pressure in a drum dryer or a pin tenter type hot air drying chamber, but depending on circumstances, drying under pressure or vacuum may be performed. At this time, it is more preferable to dry the wet paper with a drum dryer that can be effectively dried for a fixed length for the purpose of ensuring uniformity of physical properties and suppressing shrinkage in the width direction. What is necessary is just to select a drying temperature suitably in the range of 60 to 150 degreeC. In some cases, multi-stage drying such as rough drying at a low temperature of about 60 to 80 ° C. to give the wet paper self-supporting property and the main drying step at 100 ° C. or more may be effective in operation. is there.

In order to continuously form the sheet of the present embodiment, it is often effective to continuously perform the paper making process and the drying process as described above, and in some cases, the smoothing process by a calendar process. By performing the smoothing treatment by the calendar device, the above-described thinning can be achieved, and the sheet of the present invention having a wide range of film thickness / air resistance / strength combinations can be provided. As the calendar device, in addition to a normal calendar device using a single press roll, a super calendar device having a structure in which these are installed in a multistage manner may be used. By selecting the materials (material hardness) and linear pressures on both sides of the roll during the calendar process, these sheets can have various physical property balances.
Also, in the above-mentioned film-forming process by papermaking, the papermaking filter cloth or plastic wire to be used is an endless specification, and the entire process is performed with one wire, or the endless filter or endless of the next process is performed on the way. The felt cloth can be picked up and transferred or transferred, or the entire film forming process or a part of the film forming process can be made a roll-to-roll process using a filter cloth. But the manufacturing method of the separator of this embodiment is not limited to this.

Next, (A) Composite of the sheet of this embodiment and (B) resin will be described.
The cellulose fiber layer containing 50% by weight or more of regenerated cellulose fiber is designed to have a specific surface area equivalent fiber diameter of 0.20 μm or more and 2.0 μm or less. Drying shrinkage derived from cellulose hydroxyl groups during formation can be prevented, and the porosity and pore diameter can be maintained. Since the pore diameter can be maintained, the cellulose fiber layer can be easily impregnated with the resin, and the cellulose fiber layer and the resin can be combined.
Examples of the resin that can be impregnated into the regenerated cellulose fiber layer include a thermosetting resin, a photocurable resin, a resin obtained by thermosetting or photocuring these resins, and a thermoplastic resin.
Examples of thermosetting resins that can be impregnated in the regenerated cellulose fiber layer include epoxy resins, acrylic resins, oxetane resins, unsaturated polyester resins, alkyd resins, novolac resins, resol resins, urea resins, A melamine-type resin etc. are mentioned, These can also be used independently and can also use 2 or more types together.

  Thermosetting resins have excellent refractive index, improved curability, improved adhesion, improved flexibility of cured molded products, and improved handling properties due to lower viscosity of thermosetting resin compositions. For the purpose of providing a thermosetting resin composition having the above, it is preferable to add a thermosetting compound suitable for each purpose. In using these, it may be individual or a mixture of two or more. The addition amount of the thermosetting compound is preferably 10 to 1,000 parts by mass, and more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the regenerated cellulose fiber layer. When the addition amount is 10 parts by mass or more, it is effective for exhibiting thermal stability (reduction of linear thermal expansion coefficient, elasticity retention at high temperature), and when the addition amount is 1,000 parts by mass or less, thermosetting is performed. It is possible to maintain high permeability and high heat resistance of the conductive resin assembly and the cured molded product.

  The epoxy compound that can be added as a thermosetting resin is, for example, an epoxy compound containing an aromatic group having thermal stability at high temperatures. Examples include bifunctional or higher glycidyl ether type epoxy resins. For example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetrabromobisphenol A, phenol novolac, cresol novolac, hydroquinone, resorcinol, 4,4′-dihydroxy-3,3 ′, 5,5′-tetramethylbiphenyl, A glycidyl ether type epoxy resin obtained by reaction of 1,6-dihydroxynaphthalene, 9,9-bis (4-hydroxyphenyl) fluorene, tris (p-hydroxyphenyl) methane, tetrakis (p-hydroxyphenyl) ethane and epichlorohydrin Can be mentioned. In addition, an epoxy resin having a dicyclopentadiene skeleton, an epoxy resin having a biphenylaralkyl skeleton, and triglycidyl isocyanurate can be given. Moreover, an aliphatic epoxy resin and an alicyclic epoxy resin can also be mix | blended in the range which does not cause the remarkable fall of Tg.

  In addition to an epoxy compound that can be added as a thermosetting resin, it is preferable to add a liquid aromatic diamine curing agent as a curing agent. Here, the liquid state means a liquid at 25 ° C. and 0.1 MPa. The aromatic diamine curing agent means a compound having two amine nitrogen atoms directly bonded to an aromatic ring in the molecule and having a plurality of active hydrogens. Here, “active hydrogen” refers to a hydrogen atom bonded to an aminic nitrogen atom. In order to ensure the impregnation property of the reinforcing fiber, it is necessary to be liquid, and to obtain a cured product having a high Tg, it is necessary to be an aromatic diamine curing agent. For example, 4,4'-methylenebis (2-ethylaniline), 4,4'-methylenebis (2-isopropylaniline), 4,4'-methylenebis (N-methylaniline), 4,4'-methylenebis (N- Ethylaniline), 4,4'-methylenebis (N-sec-butylaniline), N, N'-dimethyl-p-phenylenediamine, N, N'-diethyl-p-phenylenediamine, N, N'-di- sec-butyl-p-phenylenediamine, 2,4-diethyl-1,3-phenylenediamine, 4,6-diethyl-1,3-phenylenediamine, 2,4-diethyl-6-methyl-1,3-phenylene Examples thereof include liquid aromatic diamine curing agents such as diamine and 4,6-diethyl-2-methyl-1,3-phenylenediamine. These liquid aromatic diamine curing agents may be used alone or in combination.

  Furthermore, a latent curing agent may be added as a resin having thermosetting properties that can be added in addition to the epoxy compound. A latent curing agent is a compound that is insoluble in an epoxy resin at room temperature, solubilized by heating, and functions as a curing accelerator. It is an imidazole compound that is solid at room temperature, and a solid-dispersed amine adduct system latency. Examples of the curing accelerator include a reaction product of an amine compound and an epoxy compound (amine-epoxy adduct system), a reaction product of an amine compound and an isocyanate compound or a urea compound (urea type adduct system), and the like.

  Examples of imidazole compounds that are solid at room temperature include 2-heptadecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2 -Phenyl-4-benzyl-5-hydroxymethylimidazole, 2,4-diamino-6- (2-methylimidazolyl- (1))-ethyl-S-triazine, 2,4-diamino-6- (2'- Methylimidazolyl- (1) ′)-ethyl-S-triazine isocyanuric acid adduct, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1 -Cyanoethyl-2-methylimidazole-trimellitate, 1 Examples include cyanoethyl-2-phenylimidazole-trimellitate, N- (2-methylimidazolyl-1-ethyl) -urea, N, N ′-(2-methylimidazolyl- (1) -ethyl) -aziboyldiamide, and the like. However, it is not limited to these.

  Examples of the epoxy compound used as one of the raw materials for producing the solid dispersion type amine adduct type latent curing accelerator (amine-epoxy adduct type) include polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcinol, glycerin, Polyglycidyl ether obtained by reacting a polyhydric alcohol such as polyethylene glycol with epichlorohydrin; reacting a hydroxycarboxylic acid such as p-hydroxybenzoic acid or β-hydroxynaphthoic acid with epichlorohydrin Glycidyl ether ester obtained by reaction of polycarboxylic acid such as phthalic acid and terephthalic acid with epichlorohydrin; epichlorohydric acid such as 4,4'-diaminodiphenylmethane and m-aminophenol Glycidylamine compounds obtained by reacting with hydrin; furthermore, polyfunctional epoxy compounds such as epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, and the like such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate. Functional epoxy compounds; and the like, but are not limited thereto.

  The amine compound used as another raw material for producing the solid dispersion-type amine adduct-based latent curing accelerator has at least one active hydrogen capable of undergoing addition reaction with an epoxy group in the molecule, and a primary amino group, What is necessary is just to have at least one functional group selected from the secondary amino group and the tertiary amino group in the molecule. Examples of such amine compounds are shown below, but are not limited thereto. That is, for example, aliphatic amines such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, 4,4'-diamino-dicyclohexylmethane; 4,4'-diaminodiphenylmethane , Aromatic amine compounds such as 2-methylaniline; heterocycles containing nitrogen atoms such as 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, piperazine Compound; and the like.

Further, a photoacid generator may be added as a thermosetting resin of the present development that can be added in addition to the epoxy compound. As the photoacid generator, one that generates an acid capable of cationic polymerization upon irradiation with ultraviolet rays is used. Examples of such a photoacid generator include anions such as SbF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , (C ₆ F ₅ ) ₄ ⁻ , and PF ₄ (CF ₂ CF ₃ ) ₂ ^−. Examples include onium salts (diazonium salts, sulfonium salts, iodonium salts, selenium salts, pyridinium salts, ferrocenium salts, phosphonium salts, and the like) composed of a component and a cationic component. These may be used alone or in combination of two or more. Specifically, aromatic sulfonium salts, aromatic iodonium salts, aromatic phosphonium salts, aromatic sulfoxonium salts, and the like can be used. Among these, from the viewpoint of photocurability and transparency, a photoacid generator containing hexafluorophosphate or hexafluoroantimonate as an anionic component is preferable.
Content of a photo-acid generator needs to set to the range of 0.5-2.0 weight part with respect to 100 weight part of total weights of an epoxy compound. More preferably, it is the range of 0.5-1.5 weight part. If the content of the photoacid generator is too small, the curability may be deteriorated or the heat resistance may be lowered. If the content is too large, the curability is improved but the transparency is impaired.

  In addition to the above-described components, other additives can be appropriately blended as necessary in addition to the above-described components in the thermosetting resin of the present invention that can be added in addition to the epoxy compound. For example, for the purpose of enhancing curability, a photosensitizer such as anthracene, an acid proliferating agent, or the like can be blended as necessary. Moreover, in the use which produces hardened | cured material on base materials, such as glass, in order to improve adhesiveness with a base material, you may add coupling agents, such as a silane type or a titanium type. Furthermore, an antioxidant, an antifoaming agent, etc. can be mix | blended suitably. These may be used alone or in combination of two or more. And it is preferable to use these other additives within the range of 5% by weight or less of the entire curable resin composition from the viewpoint of not inhibiting the effects of the present invention.

Examples of the photocurable resin that can be impregnated in the regenerated cellulose fiber layer include compounds having one or more (meth) acryloyl groups in one molecule.
The photo-curing resin has excellent properties for improving the refractive index, improving the curability, improving the adhesion, improving the flexibility of the cured molded product, and improving the handling property by reducing the viscosity of the photosensitive resin composition. For the purpose of providing a photosensitive resin composition having a compound, it is preferable to add a compound having one or more (meth) acryloyl groups in one molecule suitable for each purpose. In using these, it may be individual or a mixture of two or more. The addition amount of the compound having one or more (meth) acryloyl groups in one molecule is preferably 10 to 1,000 parts by mass, and 50 to 500 parts per 100 parts by weight of the regenerated cellulose fiber layer. More preferably, it is part by mass. When the addition amount is 10 parts by mass or more, it is effective for exhibiting thermal stability (reduction of linear thermal expansion coefficient, elasticity retention at high temperature), and when the addition amount is 1,000 parts by mass or less, it is photosensitive. It is possible to maintain high permeability and high heat resistance of the resin assembly and the cured molded product.

  The (meth) acrylate compound that can be added as a photocurable resin is, for example, a (meth) acrylate compound containing an aromatic group having thermal stability at high temperatures. Examples include phenoxyethyl acrylate, paraphenylphenoxyethyl acrylate (Aronix TO-1463 manufactured by Toagosei Co., Ltd.), paraphenylphenyl acrylate (Aronix TO-2344 manufactured by Toagosei Co., Ltd.), phenyl glycidyl ether acrylate (hereinafter “PGEA”). ), Benzyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenol (meth) acrylate modified with 3 to 15 moles of ethylene oxide, cresol (meth) modified with 1 to 15 moles of ethylene oxide Acrylate, nonylphenol (meth) acrylate modified with 1 to 20 moles of ethylene oxide, nonylphenol modified with 1 to 15 moles of propylene oxide (medium) ) Acrylate, bisphenol A di (meth) acrylate modified with 1-30 mol ethylene oxide, bisphenol A di (meth) acrylate modified with 1-30 mol propylene oxide, modified with 1-30 mol ethylene oxide Preferred are bisphenol F di (meth) acrylate and bisphenol F di (meth) acrylate modified with 1 to 30 moles of propylene oxide. In using these, it may be individual or a mixture of two or more.

It is important that a photopolymerization initiator is added to the photocurable resin for the purpose of imparting a photosensitive pattern.
Examples of the photopolymerization initiator (C) include the following photopolymerization initiators (1) to (10):
(1) Benzophenone derivatives: for example, benzophenone, methyl o-benzoylbenzoate, 4-benzoyl-4′-methyldiphenyl ketone, dibenzyl ketone, fluorenone,
(2) Acetophenone derivatives: For example, 2,2′-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one (IRGACURE651 manufactured by BASF) 1-hydroxycyclohexyl phenyl ketone (IRGACURE184 manufactured by BASF), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (IRGACURE907 manufactured by BASF), 2-hydroxy-1 -{4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] -phenyl} -2-methylpropan-1-one (IRGACURE127 manufactured by BASF), methyl phenylglyoxylate,
(3) Thioxanthone derivatives: for example, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, diethylthioxanthone,
(4) Benzyl derivatives: for example, benzyl, benzyldimethyl ketal, benzyl-β-methoxyethyl acetal,
(5) Benzoin derivatives: for example, benzoin, benzoin methyl ether, 2-hydroxy-2-methyl-1phenylpropan-1-one (manufactured by BASF, DAROCURE 1173),
(6) Oxime compounds: for example, 1-phenyl-1,2-butanedione-2- (O-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (O-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (O-benzoyl) oxime, 1,3-diphenylpropanetrione-2 -(O-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2- (O-benzoyl) oxime, 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyl) Oxime)] (IRGACURE OXE01 manufactured by BASF), ethanone, 1- [9-ethyl-6- (2-methylbenzo) Le) -9H- carbazol-3-yl] -, 1- (O- acetyloxime) (BASF Corp. IRGACURE OXE02),
(7) α-hydroxy ketone compounds: for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl -1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) -benzyl] phenyl} -2-methylpropane,
(8) α-aminoalkylphenone compounds: for example, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (IRGACURE369 manufactured by BASF), 2-dimethylamino-2- ( 4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) butan-1-one (IRGACURE 379 manufactured by BASF),
(9) Phosphine oxide compound: For example, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (IRGACURE819 manufactured by BASF), bis (2,6-dimethoxybenzoyl) -2,4,4- Trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (BASF, LUCIRIN TPO),
(10) Titanocene compound: for example, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium (manufactured by BASF) IRGACURE 784).
The photopolymerization initiators (1) to (10) may be used alone or in combination of two or more.

The content of the photopolymerization initiator is preferably 0.01% by mass or more, more preferably 0.1% by mass from the viewpoint of obtaining sufficient sensitivity based on the mass of all components other than the solvent in the photosensitive resin composition. On the other hand, from the viewpoint of sufficiently curing the bottom portion of the photosensitive resin layer, it is preferably 15% by mass or less, and more preferably 10% by mass or less.
If desired, a sensitizer for improving photosensitivity can be added to the photocurable resin. Examples of such a sensitizer include Michler's ketone, 4,4′-bis (diethylamino) benzophenone, 2,5-bis (4′-diethylaminobenzylidene) cyclopentanone, and 2,6-bis (4′-diethylamino). Benzylidene) cyclohexanone, 2,6-bis (4′-dimethylaminobenzylidene) -4-methylcyclohexanone, 2,6-bis (4′-diethylaminobenzylidene) -4-methylcyclohexanone, 4,4′-bis (dimethylamino) ) Chalcone, 4,4′-bis (diethylamino) chalcone, 2- (4′-dimethylaminocinnamylidene) indanone, 2- (4′-dimethylaminobenzylidene) indanone, 2- (p-4′-dimethylamino) Biphenyl) benzothiazole, 1,3-bis (4-dimethylaminobenzylide) ) Acetone, 1,3-bis (4-diethylaminobenzylidene) acetone, 3,3′-carbonyl-bis (7-diethylaminocoumarin), 3-acetyl-7-dimethylaminocoumarin, 3-ethoxycarbonyl-7-dimethyl Aminocoumarin, 3-benzyloxycarbonyl-7-dimethylaminocoumarin, 3-methoxycarbonyl-7-diethylaminocoumarin, 3-ethoxycarbonyl-7-diethylaminocoumarin, N-phenyl-N-ethylethanolamine, N-phenyldiethanolamine, Np-tolyldiethanolamine, N-phenylethanolamine, N, N-bis (2-hydroxyethyl) aniline, 4-morpholinobenzophenone, isoamyl 4-dimethylaminobenzoate, isoamid 4-diethylaminobenzoate , Benztriazole, 2-mercaptobenzimidazole, 1-phenyl-5-mercapto-1,2,3,4-tetrazole, 1-cyclohexyl-5-mercapto-1,2,3,4-tetrazole, 1- ( tert-butyl) -5-mercapto-1,2,3,4-tetrazole, 2-mercaptobenzothiazole, 2- (p-dimethylaminostyryl) benzoxazole, 2- (p-dimethylaminostyryl) benzthiazole, 2 -(P-dimethylaminostyryl) naphtho (1,2-p) thiazole, 2- (p-dimethylaminobenzoyl) styrene and the like. In use, it may be used alone or as a mixture of two or more.

If desired, a polymerization inhibitor can be added to the photosensitive resin composition for the purpose of improving the viscosity during storage and the stability of photosensitivity. Examples of such polymerization inhibitors include hydroquinone, N-nitrosodiphenylamine, p-tert-butylcatechol, phenothiazine, N-phenylnaphthylamine, ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, glycol etherdiaminetetraacetic acid. 2,6-di-tert-butyl-p-methylphenol, 5-nitroso-8-hydroxyquinoline, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 2-nitroso-5- (N- Ethyl-N-sulfopropylamino) phenol, N-nitroso-N-phenylhydroxyamine ammonium salt, N-nitroso-N-phenylhydroxylamine ammonium salt, N-nitroso-N- (1-naphthyl) hydroxylamine ammonium salt ,Screw Or the like can be used 4-hydroxy-3,5-di-tert- butyl) phenyl methane.
In addition to the above, the photosensitive resin composition includes various kinds of photosensitive resin compositions as necessary as long as they do not inhibit various characteristics of the photosensitive resin composition, including an ultraviolet absorber and a coating film smoothness imparting agent. Additives can be blended as appropriate.

  As the resin that can be impregnated into the regenerated cellulose fiber layer, a thermosetting resin or a photocurable resin can also be used. However, the resin is impregnated into the sheet-like base material in a short time by injection molding or the like, and used for molding a mass-produced product or the like. Therefore, it is preferable to use a thermoplastic resin from the viewpoint that it can easily cope with various molded shapes. Although it does not specifically limit as a thermoplastic resin to be used, For example, polyolefin (polyethylene, polypropylene, etc.) like general-purpose plastics, ABS, polyamide, polyester, polyphenylene ether, polyacetal, polycarbonate, polyphenylene sulfide, polyimide, polyetherimide, Polyether sulfone, polyketone, polyether ether ketone, combinations thereof, and the like can be used.

  Furthermore, inorganic fine particles may be added to the resin impregnated in the regenerated cellulose fiber layer from the viewpoint of improving the thermal stability (linear thermal expansion coefficient and elastic retention at high temperature) of the resin. As the inorganic fine particles, for example, those having excellent heat resistance include alumina, magnesia, titania, zirconia, silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, amorphous fine powder amorphous Silica, etc.), etc .; those having excellent thermal conductivity, such as boron nitride, aluminum nitride, alumina oxide, titanium oxide, magnesium oxide, zinc oxide, silicon oxide, etc .; those having excellent conductivity include simple metals or alloys (for example, , Iron, copper, magnesium, aluminum, gold, silver, platinum, zinc, manganese, stainless steel) and / or metal-coated fillers; mica, clay, kaolin, talc , Zeolite, wollastonite, smectite and other minerals, potassium titanate, magnesium sulfate , Sepiolite, zonolite, aluminum borate, calcium oxide, titanium oxide, barium sulfate, zinc oxide, magnesium hydroxide; those with a high refractive index include barium titanate, zirconia oxide, titanium oxide, etc .; exhibiting photocatalytic properties As photocatalytic metals such as titanium, cerium, zinc, copper, aluminum, tin, indium, phosphorus, carbon, sulfur, terium, nickel, iron, cobalt, silver, molybdenum, strontium, chromium, barium, lead, etc. Composites, oxides thereof, and the like; Metals such as silica, alumina, zirconia, magnesium, etc., and composites and oxides, etc .; excellent conductivity, silver, copper Metals such as tin oxide, indium oxide, etc .; Silica etc. as materials having excellent insulating properties; purple The excellent in line shielding, titanium oxide, zinc oxide and the like. These inorganic fine particles may be appropriately selected depending on the application, and may be used alone or in combination of two or more. The inorganic fine particles have various characteristics other than the special products mentioned in the examples, and may be selected according to the timely use.

  For example, when silica is used as the inorganic fine particles, there is no particular limitation, and known silica fine particles such as powdered silica and colloidal silica can be used. Examples of commercially available powdered silica fine particles include Aerosil 50 and 200 manufactured by Nippon Aerosil Co., Ltd., Sildex H31, H32, H51, H52, H121, and H122 manufactured by Asahi Glass Co., Ltd., and E220A manufactured by Nippon Silica Industry Co., Ltd. E220, SYLYSIA470 manufactured by Fuji Silysia Co., Ltd., SG flake manufactured by Nippon Sheet Glass Co., Ltd., and the like. Examples of commercially available colloidal silica include methanol silica sol manufactured by Nissan Chemical Industries, Ltd., IPA-ST, PGM-ST, NBA-ST, XBA-ST, DMAC-ST, ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, ST-OL, etc. can be mentioned.

  Surface-modified silica fine particles may be used. For example, the silica fine particles may be surface-treated with a reactive silane coupling agent having a hydrophobic group or those modified with a compound having a (meth) acryloyl group. can give. As commercially available silica powder modified with a compound having a (meth) acryloyl group, as commercially available colloidal silica modified with a compound having a (meth) acryloyl group, such as Aerosil RM50, R7200, R711 manufactured by Nippon Aerosil Co., Ltd. Is a colloidal silica surface-treated with a reactive silane coupling agent having a hydrophobic group, such as MIBK-SD, MEK-SD, manufactured by Nissan Chemical Industries, Ltd., MIBK-ST, manufactured by Nissan Chemical Industries, Ltd., MEK-ST etc. are mentioned.

The shape of the silica fine particles is not particularly limited, and those having a spherical shape, a hollow shape, a porous shape, a rod shape, a plate shape, a fiber shape, or an indefinite shape can be used. For example, as a commercially available hollow silica fine particle, Sirenax manufactured by Nittetsu Mining Co., Ltd. can be used.
The primary particle diameter of the inorganic fine particles is preferably in the range of 5 to 2,000 nm. When it is 5 nm or more, the inorganic fine particles in the dispersion are excellently dispersed, and when the diameter is within 2,000 nm, the strength of the cured product is good. More preferably, it is 10 nm to 1,000 nm. The “particle size” here is measured using a scanning electron microscope (TEM) or the like.
The inorganic fine particles are preferably blended at a ratio of 5 to 50% by weight with respect to the total solid content of the resin composite. For example, in the case of a heat resistant material, the silica fine particles are preferably 5 to 50% by weight in order to achieve both a low linear expansion coefficient and a high strength of the cured product, and 20 to 20% in order to further reduce the linear expansion coefficient. More preferably, it is added in a proportion of 50% by weight, more preferably 30 to 50% by weight.

  In the resin impregnation into the regenerated cellulose fiber layer, the viscosity can be adjusted by adding a solvent as necessary. Suitable solvents include N, N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, tetrahydrofuran, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphoramide, pyridine, cyclohexane Pentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone Methyl isobutyl ketone, anisole, ethyl acetate, ethyl lactate, butyl lactate and the like, and these can be used alone or in combination of two or more. Among these, N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monomethyl ether acetate are particularly preferable. These solvents can be appropriately added at the time of resin impregnation into the regenerated cellulose fiber layer depending on the coating film thickness and viscosity.

  The method for impregnating the regenerated cellulose fiber layer with resin is not particularly limited, but after shaping and / or laminating a prepreg impregnated with a thermosetting resin composition on a sheet, the shaped product and / or laminating is performed. A prepreg laminate molding method in which a resin is heated and cured while applying pressure to the product, a resin transfer molding method in which a sheet is directly impregnated with a liquid thermosetting resin composition, and then cured, and a sheet in a liquid thermosetting resin composition It is manufactured by a pultrusion method that is continuously passed through a filled impregnation tank and impregnated with a thermosetting resin composition, and then molded and cured while being continuously pulled out by a pulling machine through a squeeze die and a heating mold. Can do.

Examples of the method for impregnating the resin include a wet method and a hot melt method (dry method).
In the wet method, after immersing the sheet in a solution in which an epoxy resin composition, a photocurable resin composition, or a thermoplastic resin is dissolved in a solvent such as methyl ethyl ketone, the sheet is pulled up, and the solvent is evaporated using an oven or the like. This is a method of impregnating a resin. The hot melt method is an epoxy resin composition or a photocurable resin composition whose viscosity is reduced by heating, a method in which a sheet is directly impregnated with a thermoplastic resin, or a film in which an epoxy resin composition is coated on release paper or the like. Then, it is a method in which the reinforcing fiber is impregnated with resin by overlapping the film from both sides or one side of the reinforcing fiber and heating and pressing. At this time, it is preferable to deaerate air by putting a vacuum defoaming step. Further, since there is no solvent remaining in the prepreg, it is preferable to use a hot melt method.

  The content of the cellulose fiber layer in the prepreg or its cured resin or thermoplastic resin is preferably 1 to 80% by weight, more preferably 5 to 50% by weight, and further preferably 10 to 30% by weight. . When the weight content of the cellulose fiber layer is less than 1% by weight, the ratio of the resin is too high, so that it is difficult to obtain the advantage of the composite material having excellent linear thermal expansion coefficient and elastic modulus when combined. In addition, when the mass content of the reinforcing fibers exceeds 80% by weight, the amount of impregnation of the resin is insufficient, so that the obtained composite material has many voids, and the strength required as a film is lowered.

The sheet according to the present embodiment can be suitably used as a core material for fiber reinforced plastics, more specifically as a core material or a core material for in-vehicle or aircraft materials. That is, particularly when it is made of fiber reinforced plastic, it can meet the needs for high elasticity, high heat resistance, and light weight in the fields of in-vehicle and aircraft materials. As an in-vehicle application, since the flexibility of formability is high, it is used for both interior and exterior, and is used for roofs, bumpers, doors, front end modules, and the like. Furthermore, since the sheet has flatness and low defects, various application designs are facilitated.
Moreover, since it has a high elastic modulus as a single sheet or a core material, it can also be used as a material for absorbing and blocking sound and vibration, and it can also be used as a heat dissipation sheet because of its excellent thermal conductivity.
Since the sheet of this embodiment becomes high-strength and lightweight by compounding with a resin, it can be substituted for a steel plate and carbon fiber reinforced plastic. Examples include industrial machine parts (eg, electromagnetic equipment casings, roll materials, transfer arms, medical equipment members, etc.), general machine parts, automobile / railway / vehicle parts (eg, outer plates, chassis, aerodynamics). Members, seats, etc.), ship components (eg, hulls, seats, etc.), aircraft-related parts (eg, fuselage, main wing, tail wing, moving wing, fairing, cowl, door, seat, interior materials, etc.), spacecraft, artificial satellite Member (motor case, main wing, structure, antenna, etc.), electronic / electrical parts (eg personal computer housing, mobile phone housing, OA equipment, AV equipment, telephone, facsimile, household appliances, toy supplies, etc.), construction / civil engineering Materials (for example, rebar replacement materials, truss structures, cables for suspension bridges, etc.), household items, sports / leisure items (for example, golf club shafts, fishing rods, teni And like racket badminton), a wind power generation housing member or the like, also containers and packaging member, for example, it can be a material for the high pressure container for filling and hydrogen gas as used in a fuel cell.
In addition to the above-mentioned uses, it can be applied as materials such as various functional papers, absorbent materials, and supports for medical materials.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the scope of the present invention is not limited to the following Example.
[Production of sheet]
[Example 1]
Put the tencel cut yarn (3mm length), a regenerated cellulose fiber obtained from Sojitz Corporation, into the washing net, add a surfactant, and wash it with water many times in the washing machine to remove the oil on the fiber surface. did. The obtained refined tencel fiber (cut yarn) was dispersed in water to a solid content of 1.5% by weight (400 L), and SDR14 type laboratory refiner (pressure type DISK) manufactured by Aikawa Tekko Co., Ltd. was used as a disc refiner device. Using a formula, 400 L of the aqueous dispersion was beaten for 20 minutes with a disc clearance of 1 mm. Subsequently, beating was carried out under conditions where the clearance was reduced to almost zero, and a beating water dispersion (solid content concentration: 1.5% by weight) was obtained. The obtained beating water dispersion was subjected to refinement treatment 5 times under an operating pressure of 100 MPa using a high-pressure homogenizer (NS015H manufactured by Niro Soabi (Italy)) as it was, and an aqueous dispersion M1 of cellulose fibers (solid) Minor concentration: 1.5% by weight).

Subsequently, the water dispersion M1 was diluted to a solid content concentration of 0.1% by weight and dispersed with a blender, and then a plain fabric made of PET / nylon blend (NT20, manufactured by Shikishima Canvas Co., Ltd.) Permeation amount: 0.03ml / cm ² · s, batch type paper machine (automatic square type manufactured by Kumagai Riki Kogyo Co., Ltd.) set with cellulose fiber capable of filtering 99% or more by filtration at 25 ° C under atmospheric pressure Using the cellulose sheet having a basis weight of 4 g / m ^{2 on} a sheet machine (25 cm × 25 cm, 80 mesh) as a guide, the adjusted papermaking slurry was charged, and then papermaking (dehydration) was performed at a reduced pressure of 4 KPa with respect to atmospheric pressure.
The wet paper made of the concentrated composition on the obtained filter cloth is peeled off from the wire and the wet paper surface is brought into contact with the drum surface so that the wet paper / filter cloth has a two-layer surface. Drum dryer set at a temperature of 130 ° C is dried for about 120 seconds so that the wet paper is in contact with the drum surface, and the filter cloth is peeled from the cellulose sheet-like structure from the resulting dried two-layer body. Thus, a sheet (25 cm × 25 cm) S1 composed of white uniform cellulose fibers shown in Table 1 below was obtained.

[Example 2]
To the papermaking slurry prepared by diluting M1 of Example 1 with water, the papermaking slurry adjusted to be a cellulose sheet having a basis weight of 15 g / m ² was charged, and the obtained wet paper was used as a wet paper / filter cloth. A sheet S2 made of white cellulose shown in Table 1 below was obtained by the same operation as in Example 1 except that it was dried in a drying oven set at 130 ° C. in a two-layer state.

[Example 3]
The same operation as in Example 1 is carried out except that the papermaking slurry prepared by diluting M1 of Example 1 with water is adjusted so as to be a cellulose sheet having a basis weight of 50 g / m ^2. Thus, a sheet S3 made of white cellulose shown in Table 1 below was obtained.

[Example 4]
The same operation as in Example 1 is carried out except that the papermaking slurry prepared by diluting M1 of Example 1 with water is adjusted to be a cellulose sheet having a basis weight of 100 g / m ^2. Thus, a sheet S4 made of white cellulose shown in Table 1 below was obtained.

[Example 5]
By operating in the same manner as in Example 2, except that the papermaking slurry prepared in M1 of Example 2 and a hydrophilic polypropylene long fiber nonwoven fabric with a basis weight of 20 g / m ² obtained from Asahi Kasei Fibers Co., Ltd. were used. A sheet S5 made of white cellulose shown in Table 1 below was obtained.

[Example 6]
By performing the same operation as in Example 1 except that the papermaking slurry prepared in M1 of Example 2 and a cellulose continuous fiber nonwoven fabric having a basis weight of 17 g / m ² obtained from Asahi Kasei Fibers Co., Ltd. were used. A sheet S6 made of white cellulose shown in Table 1 was obtained.

[Example 7]
Aramid pulp, which is an organic polymer as a raw material, was put into a washing net, a surfactant was added, and the oil agent on the fiber surface was removed by washing with a washing machine many times. The obtained refined tencel fiber (cut yarn) was dispersed in water to a solid content of 1.5% by weight (400 L), and SDR14 type laboratory refiner (pressure type DISK) manufactured by Aikawa Tekko Co., Ltd. was used as a disc refiner device. Using a formula, 400 L of the aqueous dispersion was beaten for 20 minutes with a disc clearance of 1 mm. Subsequently, beating was carried out under conditions where the clearance was reduced to almost zero, and a beating water dispersion (solid content concentration: 1.5% by weight) was obtained. The obtained beating water dispersion was subjected to a micronization treatment under an operating pressure of 100 MPa using a high-pressure homogenizer (NS015H manufactured by Niro Soabi (Italy)) as it was, and an aqueous dispersion M2 of aramid nanofibers (solid content concentration) : 1.5% by weight). Subsequently, as a solid content weight composition, water dispersion M1 solid content: water dispersion M2 solid content = 50: 45, mixed so that the solid content concentration is 0.1% by weight, diluted with water, A sheet S7 made of white cellulose shown in Table 1 below was obtained by the same operation as in Example 1 except that 5% by weight of the chemical weight was added.

[Example 8]
Linter pulp, which is natural cellulose as a raw material, is immersed in water to 4% by weight, heat-treated in an autoclave at 130 ° C. for 4 hours, and the resulting swollen pulp is washed with water many times and impregnated with water. A swollen pulp in a finished state was obtained. This was subjected to beating treatment in the same manner as in Example 1, and subsequently subjected to refinement treatment 5 times at an operating pressure of 100 MPa using a high-pressure homogenizer, to obtain an aqueous dispersion M3 having a solid content concentration of 1.5 wt%. Subsequently, by mixing the aqueous dispersion M1 solid content: the aqueous dispersion M3 solid content 55:45 and the solid content concentration of 0.1% by weight as the solid weight composition, the same operation as in Example 1 was performed. A sheet S8 made of white cellulose shown in Table 1 below was obtained.

[Example 9]
A sheet S9 made of white cellulose shown in Table 1 below was obtained by the same operation as in Example 8 except that the basis weight was changed.

[Example 10]
A sheet S10 made of white cellulose shown in Table 1 below was obtained by performing the same operations as in Example 2 except that the number of times of the fine processing was thoroughly performed.

[Example 11]
The aqueous dispersion (solid content concentration: 1.5 wt%) obtained in Example 10 and thoroughly beaten and refined was diluted to a solid content concentration of 0.2%. Thereafter, centrifugation was performed at a rotation speed of 8,000 rpm for 20 minutes using a centrifuge (KUBOTA 7780). Thereafter, the supernatant liquid generated in the upper part of the aqueous dispersion was separated by decantation. This supernatant was diluted to a solid content concentration of 0.1% by weight and dispersed with a blender. Then, a plain fabric made of PET / nylon blend (manufactured by Shikishima Canvas, NT20, water permeation amount at 25 ° C. in the atmosphere: 0.00). A batch type paper machine (manufactured by Kumagai Riki Kogyo Co., Ltd., automatic square sheet machine 25 cm x 25 cm) with a capacity of 03 ml / cm ² · s, capable of filtering 99% or more of cellulose fibers by filtration at 25 ° C under atmospheric pressure 80 mesh), with the basis of a cellulose sheet having a basis weight of 10 g / m ² , except that the adjusted papermaking slurry was added, the same procedure as in Example 1 was performed to produce white cellulose shown in the following table. Sheet S11 was obtained.

[Example 12]
A sheet S12 made of white cellulose shown in Table 1 below was obtained by the same operation as in Example 11 except that the basis weight was changed.

[Example 13]
By performing operations in the same manner as in Example 1 except that thorough beating is performed, fine processing is not performed, and the basis weight is changed as shown in Table 1 below, the following operations are performed. A sheet S13 made of white cellulose shown in Table 1 was obtained.

[Example 14]
The white cellulose shown in Table 1 below is obtained by performing the same operation as in Example 1 except that the refinement process is not performed and the basis weight is changed as shown in Table 1 below. The produced sheet S14 was obtained.

[Comparative Example 1]
The papermaking slurry prepared by diluting the water dispersion M2 of linter pulp, which is the natural cellulose produced in Example 7, with water was prepared, except that the papermaking slurry adjusted to a cellulose sheet with a basis weight of 15 g / m ² was added. The same operation as in Example 1 was performed to obtain a reference sheet R1 shown in Table 1 below.

[Sheet evaluation]
(1) Composition Table 1 summarizes and describes the raw materials and content ratios of the sheets produced in Examples 1 to 14 and Comparative Example 1.
(2) Measurement of sample thickness Using a Mitutoyo film thickness meter (Model ID-C112XB), a 10 cm × 10 cm square piece was cut out from the sheet, and the average value of the five measured values at various positions was determined as the film thickness T. (Μm).
(3) Measurement of basis weight of cellulose sheet Five weights per 1 m ² were calculated from the weight W (g) of the 10.0 cm × 10.0 cm square piece cut out in the above (2) and calculated from the average value.
(4) Calculation of porosity of molded body From the film thickness d (μm) and weight W (g) of the 10.0 cm × 10.0 cm square piece cut out in (2) above, the porosity of the film Pr (%) was evaluated at 5 points and calculated from the average value.
(5) Specific surface area equivalent fiber diameter measurement After measuring the adsorption amount of nitrogen gas at the boiling point of liquid nitrogen to about 0.2 g of a sheet sample with a specific surface area / pore distribution measuring device (manufactured by Beckman Coulter), The specific surface area (m ² / g) is calculated by the apparatus program, and is a cylinder model (assuming that the fiber is formed into a cylinder having a circular cross section when assuming an ideal state in which no fusion between fibers occurs and the cellulose density is 1.50 g / ml. Based on the formula (fiber diameter = 2.67 / specific surface area) introduced from the surface area / volume ratio in the case where the length is ∝), the fiber diameter corresponding to the specific surface area was calculated from the average value obtained by evaluating the specific surface area three times.
(6) Measurement of air permeability resistance of membrane Using a Gurley type densometer (model G-B2C, manufactured by Toyo Seiki Co., Ltd.), measurement of the permeation time (unit: s / 100 cc) of 100 cc of the sheet at room temperature went. As an index of film uniformity, the measurement was performed at five points for various positions of the film.
(7) Resin impregnation In the composition of Example 1-14 and Comparative Example 1, 10 μl of an epoxy monomer (Epolite 100MF, manufactured by Kyoeisha Chemical Co., Ltd.) was dropped on the sheet, and the permeability was evaluated. The case where it penetrated to the back surface 3 minutes after the dropping was marked with ◯, and the case where it did not penetrate was marked with x.

[Production of composite prepreg film]
[Example 15]
A composite prepreg film was produced by impregnating the sheet S2 with a resin component. A 10 cm square sheet and a 100 μm thick spacer were placed on a PET film coated with a release agent. A liquid mixture prepared by mixing and mixing in advance with the composition shown in Table 2 was dropped onto the sheet, and a PET film coated with a release agent was placed thereon. A composite prepreg film obtained by impregnating white cellulose listed in Table 2 below with an epoxy resin by pressing this sheet from the top of the PET film at 10 kg / cm ² while vacuum defoaming and allowing it to stand at room temperature for several days. C1 was obtained.

[Compound names used as compositions shown in Table 2]
C1
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)

[Production of composite film]
[Examples 16 to 24, Comparative Examples 2 to 4]
A composite film was produced by impregnating the sheet with a resin component. A 10 cm square sheet and a spacer having a predetermined thickness were placed on a PET film coated with a release agent. The composition and the sheet shown in Table 2 that had been stirred and mixed in advance were combined, and a PET film coated with a release agent was placed thereon. This sheet was vacuum degassed while being pressed from above the PET film at 10 kg / cm ² . This was put into a drier and cured or melted by heat or ultraviolet irradiation to obtain a composite film C2-10 in which white cellulose described in Table 2 below was impregnated with a resin, and a reference sheet RC2-4. .

[Compound names used as compositions shown in Table 2]
C2
Epoxy resin: Epoxy resin JER828 (Mitsubishi Chemical Corporation)
Curing agent: ST12 (Mitsubishi Chemical Corporation)
C3
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)
C4
Thermoplastic resin: Polypropylene film C5
Thermoplastic resin: Polypropylene film C6
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)
C7
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)
C8
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)
C9
Epoxy resin: Epoxy resin JER825 (Mitsubishi Chemical Corporation)
Curing Agent: Latent Curing Agent Fuji Cure FXE1000 (Fuji Kasei Co., Ltd.)
Inorganic fine particles: Colloidal silica (manufactured by Nissan Chemical Co., Ltd.)
RC1
Epoxy resin: Epoxy resin JER828 (Mitsubishi Chemical Corporation)
Curing agent: ST12 (Mitsubishi Chemical Corporation)
RC2
Thermoplastic resin: Polypropylene film RC3
Epoxy resin: Epoxy resin JER828 (Mitsubishi Chemical Corporation)
Curing agent: ST12 (Mitsubishi Chemical Corporation)

[Composite prepreg film evaluation]
(1) Composition In Example 15, the raw materials and content ratio used for preparation of the composite prepreg film were summarized and described in Table 2.
(2) Measurement of sample thickness Using a Mitutoyo film thickness meter (Model ID-C112XB), a 10 cm x 10 cm square piece was cut out from the composite prepreg film, and the average value of five measured values at various positions was measured. d (μm).
(3) Resin impregnation In the composition of Example 15, 10 μl of an epoxy monomer (Epolite 100MF, manufactured by Kyoeisha Chemical Co., Ltd.) was dropped on the sheet, and the permeability was evaluated. The case where it penetrated to the back surface 3 minutes after the dropping was marked with ◯, and the case where it did not penetrate was marked with x.

"Composite film evaluation"
(1) Composition In Tables 16 to 24 and Comparative Examples 2 to 4, the raw materials and content ratios used for producing the composite films are summarized and described in Table 2.
(2) Measurement of sample thickness Using a film thickness meter (Model ID-C112XB) manufactured by Mitutoyo, a 10 cm × 10 cm square piece was cut out from the composite film, and the average value of five measured values at various positions was determined as the film thickness d. (Μm).
(3) Resin impregnation In the composition of Example 14-21 and Comparative Example 2-4, 10 μl of an epoxy monomer (Epolite 100MF, manufactured by Kyoeisha Chemical Co., Ltd.) was dropped on the sheet, and the permeability was evaluated. The case where it penetrated to the back surface 3 minutes after the dropping was marked with ◯, and the case where it did not penetrate was marked with x.
(4) Evaluation of peelability After the composite film was cut into a strip of 10 cm x 2.5 cm, a cut was made in the vicinity of the composite film core on the short side with a cutter. After that, when the tape was applied to the surface of the composite film and the 90-degree peel test with the tape was attempted, the tape peeled off from the composite film was peeled off at the interface between the composite film core and the resin. The thing that had woken up was marked as x.
(5) Evaluation of linear thermal expansion coefficient Using the composite film cut out in (2) above, TMA / SS6100 manufactured by Seiko Instruments Inc. was used to raise and lower the temperature once at a rate of 10 ° C./min. Thereafter, an average linear expansion coefficient of 100 to 150 ° C. was measured when the temperature was increased again at a rate of 10 ° C./min.
(6) Elastic modulus improvement evaluation Using a film produced as a composite film thickness of 2 mm in the compositions of Examples 15 to 24 and Comparative Examples 2 to 4, a test piece having a width of 10 mm and a length of 60 mm was obtained from this resin cured product. Was cut using an Instron universal testing machine (Instron) and subjected to three-point bending according to JIS K7171 (1994), and the elastic modulus was measured. The average value of the values measured with the number of samples n = 3 is taken as the elastic modulus value, and the elastic modulus improvement effect is 1.2 times or more compared with the elastic modulus of the reference sheet (RC1 and RC2) where no film is present. Those marked with a mark marked with ◯ were marked with a mark marked with ◎.

[Evaluation]
The composite prepreg film of Example 15 and the composite films of Examples 16 to 24 produced by compounding the sheets obtained in Examples 1 to 14 and each resin have a specific surface area equivalent fiber diameter of 0.20 μm. By using the regenerated cellulose having a size of 2.0 μm or less, a sheet having a large pore size and a high porosity can be designed. Therefore, resin impregnation into the sheet is high, and the composite is easy. Moreover, by using nanofibers, the effect of improving the peelability when combined with the resin, the reduction of the linear thermal expansion coefficient, and the improvement of the elastic modulus were exhibited.
On the other hand, the composite film of Comparative Example 4 produced by combining the film obtained in Comparative Examples 2 and 3 and the resin of Comparative Example 1 does not have a sheet layer or has a specific surface area equivalent. Since the fiber diameter was 0.1 μm, it was found that the coefficient of linear thermal expansion could not be reduced due to the fact that the resin was hardly impregnated even if the fiber diameter was combined.

  Although the sheet of the present invention is a thick film as a sheet, it has a limited range of air permeability resistance, that is, it has excellent resin impregnation properties because it has a pore diameter, for example, when used as a core material for fiber reinforced plastics. Can provide thermal stability (reduction of linear thermal expansion coefficient and elastic retention at high temperature) when combined with resin, and when used as a core material for in-vehicle materials, Since the sheet strength can be ensured while being lightweight, it can be suitably used in these fields.

Claims (33)

A sheet composed of a single layer including at least one cellulose fiber layer containing 50% by weight or more of regenerated cellulose fibers or a plurality of layers of 3 or less layers, and the following requirements:
(1) The specific surface area equivalent fiber diameter of the fibers constituting the cellulose fiber layer is 0.20 μm or more and 2.0 μm or less;
(2) The air resistance of the sheet is 1 s / 100 ml or more and 400,000 s / 100 ml or less; and (3) The thickness of the sheet is more than 22 μm;
A sheet characterized by satisfying   The sheet according to claim 1, wherein the cellulose fiber layer contains 70% by weight or more of regenerated cellulose fibers.   The sheet according to claim 1 or 2, wherein the air resistance is 5 s / 100 ml or more and 20,000 s / 100 ml or less.   The regenerated cellulose fiber contains at least fine cellulose fiber, the specific surface area equivalent fiber diameter of the fine cellulose fiber is 0.20 μm or more and 2.0 μm or less, and the cellulose fiber layer has a fiber diameter of 3 μm or more and 15 μm or less. The sheet | seat of any one of Claims 1-3 in which the fiber of more than 0 weight% and 30 weight% or less is contained.   The sheet | seat of any one of Claims 1-4 whose film thickness of the said sheet | seat is more than 100 micrometers.   The sheet according to any one of claims 1 to 5, wherein the fiber constituting the cellulose fiber layer has a specific surface area equivalent fiber diameter of 0.20 µm or more and 0.45 µm or less. The sheet according to any one of claims 1 to 6, wherein the basis weight of the cellulose fiber layer is 2 g / m ² or more.   The sheet | seat of any one of Claims 1-7 in which a natural cellulose fiber is contained in the said cellulose fiber layer at less than 50 weight%.   The sheet according to claim 8, wherein the cellulose fiber layer contains less than 30 wt% of natural cellulose fibers.   The sheet | seat of any one of Claims 1-7 in which the fiber which consists of organic polymers other than a cellulose is contained in the said cellulose fiber layer at less than 50 weight%.   The sheet | seat of Claim 10 in which the fiber which consists of organic polymers other than a cellulose is contained in the said cellulose fiber layer at less than 30 weight%.   The sheet according to claim 10 or 11, wherein the fiber made of an organic polymer other than cellulose is an aramid fiber and / or a polyacrylonitrile fiber.   The sheet | seat of any one of Claims 1-12 in which the said cellulose fiber layer contains a reactive crosslinking agent by 10 weight% or less. And further with a multi-layer structure of the three layers or less, a basis weight including the base layer is a nonwoven fabric or paper is 5 g / m ² or more 200 g / m ² or less, according to any one of claims 1 to 13 Sheet. More and to having a basis weight including the base layer is a nonwoven fabric or paper is 10 g / m ² or more 100 g / m ² or less, a sheet according to claim 14 of the multi-layer structure of the three layers or less.   The manufacturing method of the sheet | seat of any one of Claims 1-15 including an aqueous papermaking process.   The manufacturing method of the sheet | seat of any one of Claims 1-15 including a coating process.   The sheet according to any one of claims 1 to 15, which is used for sound insulation.   (A) A composite film in which the sheet according to any one of claims 1 to 15 is impregnated with (B) a resin.   The composite film according to claim 19, wherein the (B) resin is one or more resins selected from the group consisting of a thermoset resin, a photocured resin, and a thermoplastic resin.   The composite film according to claim 19 or 20, wherein the (B) resin is one or more of an epoxy resin, an acrylic resin, and a general-purpose plastic.   The composite film according to any one of claims 19 to 21, wherein the (B) resin contains inorganic fine particles in an amount of less than 50 mass%. The composite film according to claim 22, wherein the inorganic fine particles are one or more selected from the group consisting of SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , MgO, ZnO, and BaTiO ₃ .   (A) A composite prepreg film comprising the sheet according to any one of claims 1 to 15, and (B) a thermosetting resin and / or a photocurable resin.   The composite prepreg film according to claim 24, wherein the (B) resin is an epoxy resin, an acrylic resin, and / or a polyimide resin.   The composite prepreg film according to claim 24 or 25, wherein the (B) resin contains inorganic fine particles in an amount of less than 50 mass%. Wherein the inorganic fine particles _{is SiO 2, TiO 2, Al 2} O 3, ZrO 2, MgO, ZnO, and one or more selected from the group consisting of BaTiO _3, the composite prepreg film according to claim 26.   The core material for fiber reinforced plastic films containing the sheet | seat of any one of Claims 1-15.   The core material for fiber-reinforced plastic films according to claim 28, for an in-vehicle material.   29. The fiber reinforced plastic film core material according to claim 28, for an electronic material. A prepreg for a fiber-reinforced plastic film comprising the sheet according to any one of claims 1 to 15.
  The fiber reinforced plastic film containing the sheet | seat of any one of Claims 1-15.   33. A fiber reinforced plastic film according to claim 32 for in-vehicle materials.