JP6079341B2 - Manufacturing method of fiber resin molding - Google Patents

Description

  The present invention relates to a method for producing a fiber-resin molded body having smooth surfaces on both sides using a resin varnish containing cellulose fibers.

  In recent years, in the fields of liquid crystal displays, organic EL displays, optical members and protective films for organic EL lighting, insulating materials for laminated substrates, and the like, resin molded bodies having both low linear expansion and surface smoothness have been demanded.

  Various approaches have been taken to achieve low linear expansion of materials, but in recent years, composite materials using cellulose fibers have attracted attention. Since cellulose has a rigid structure derived from intramolecular and intermolecular hydrogen bonds, it exhibits a low linear expansion similar to that of glass despite being an organic substance. Therefore, by combining with a resin or the like, a low linear expansion material that cannot be realized by a conventional polymer material can be obtained. Cellulose is a natural wood-derived material, and the significance of research is significant from the viewpoint of resource conservation and the realization of a low-carbon society.

  However, when a composite material containing cellulose fibers is produced by a conventional method, it has been difficult to obtain a fiber resin molded body having both low linear expansion and surface smoothness.

  For example, Patent Documents 1 to 3 disclose that a cellulose fiber non-woven fabric is impregnated with a liquid resin precursor and cured to produce a composite of cellulose fiber and resin. In order to remove roughness and waviness derived from the surface of the cellulose fiber nonwoven fabric, it is necessary to thicken the outermost resin layer of the composite to some extent. If the outermost resin layer of the composite is made thicker in order to obtain surface smoothness, the net cellulose fiber content in the composite is lowered, and there is a problem that the expected low linear expansion cannot be obtained.

  As a method for overcoming such a problem, a production method in which a resin varnish containing cellulose fibers is cast and cured can be considered. However, in order to obtain a composite exhibiting sufficient low linear expansion by this method, it is necessary to make the cellulose fiber content in the resin varnish at least 15% by weight or more. The resin varnish cannot be cast because it does not have fluidity.

  Therefore, it is conceivable that the cellulose varnish-containing resin varnish is dispersed in a solvent to make it flowable, and then formed on a substrate, desolvated, and then cured, but in this method, the surface of the varnish is removed during desolvation. As a result, there was a problem that unevenness was generated on the surface, and a double-side smooth fiber resin molded product could not be obtained.

JP 2006-316253 A JP 2007-165357 A JP 2008-127510 A

  The present invention uses a cellulose fiber-containing resin varnish that contains 15% by weight or more of cellulose fibers in a solid content and loses fluidity when the solvent is removed to produce a double-sided smooth fiber resin molding. It is an object of the present invention to provide a method for producing a fiber resin molded product that can be manufactured.

  As a result of intensive studies and repeated experiments by the present inventors, the smoothness of the substrate surface is transferred by forming the cellulose fiber-containing resin varnish on each of the two substrates, and bonding and curing them. It is possible to obtain a fiber resin molded body having both smoothness and low linear expansion, and in that case, the resin film containing no cellulose fiber or a low content of cellulose fiber on the film-forming surface of the varnish to be bonded. It was found that by applying the varnish, it was possible to adhere to the bonded surface without forming a void, and the present invention was reached.

That is, the present invention is a method for producing a fiber resin molded body in which cellulose fibers are dispersed in a resin, and the cellulose fibers and the curable resin and / or the curable resin are respectively formed on the first substrate and the second substrate. A fiber dispersion containing a resin precursor, wherein a fiber dispersion having a cellulose fiber content of 15% by weight or more in the solid content of the fiber dispersion is formed, and the fiber formed on the first substrate Further, a resin dispersion containing a curable resin and / or a curable resin precursor is applied on the dispersion film, and then the fiber dispersion of the first substrate and the second substrate is formed. Then, the fiber dispersion and resin dispersion on the first substrate and the curable resin and / or curable resin precursor in the fiber dispersion on the second substrate are cured. It characterized that you integrated Te, a method of manufacturing a fiber resin molded body, Exist for.

  According to the present invention, using a cellulose fiber-containing resin varnish with poor fluidity that contains 15% by weight or more of cellulose fibers in the solid content, a double-side smooth fiber resin molded product can be obtained. For this reason, the cellulose fiber content rate in a fiber resin molding can be made high, and the material which made compatible both double-sided smoothness and low linear expansion property is realizable. The fiber resin molded body having both low linear expansion and smoothness on both sides manufactured by the method for manufacturing a fiber resin molded body of the present invention is, for example, a liquid crystal display, an organic EL display, an optical member or protective film for organic EL lighting, Alternatively, it is industrially useful as an insulating material for a laminated substrate.

It is typical sectional drawing which shows an example of embodiment of the manufacturing method of the fiber resin molding of this invention. It is typical sectional drawing which shows the other example of embodiment of the manufacturing method of the fiber resin molding of this invention.

  Embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention does not exceed the gist thereof. The content of is not specified.

  The method for producing a fiber resin molded body of the present invention is a method for producing a fiber resin molded body in which cellulose fibers are dispersed in a resin (hereinafter, sometimes referred to as “fiber resin molded body of the present invention”). A fiber dispersion containing cellulose fibers and a curable resin and / or a curable resin precursor on the first substrate and the second substrate, respectively, and a cellulose fiber content in a solid content of 15% by weight or more. After forming a film and further providing a resin dispersion containing a curable resin and / or a curable resin precursor on the fiber dispersion film formed on the first substrate, the first substrate and the The surfaces of the second substrate on which the dispersion is formed are bonded together, and then the curable resin and / or curable resin precursor is cured.

[Cellulose fiber]
First, the cellulose fiber contained in the fiber resin molding of the present invention will be described.

  Although the cellulose fiber used for this invention is not specifically limited, Usually, what used the cellulose fiber raw material from which the impurity was removed through the refinement | purification process further from the cellulose content enumerated below should be used. Is preferred.

<Cellulose-containing material>
Examples of cellulose-containing materials include woods such as conifers and hardwoods (wood flour, etc.), cotton such as cotton linter and cotton lint, pomace such as sugar cane and sugar radish, bast fibers such as flax, ramie, jute and kenaf Plant-derived materials such as leaf vein fibers such as sisal and pineapple, petiole fibers such as abaca and banana, fruit fibers such as coconut palm, stem trunk fibers such as bamboo, etc .; bacterial cellulose produced by bacteria; Natural cellulose such as; These natural celluloses are preferable because of their high crystallinity and low linear expansion and high elastic modulus. Among these, plant-derived materials are preferable.

  Such cellulose-containing material may be subjected to a purification treatment to be described later as necessary to remove impurities, but those containing some impurities may be used.

<Purification treatment>
It is preferable to subject the cellulose-containing material to a purification treatment to remove substances other than cellulose in the cellulose-containing material, for example, lignin, hemicellulose, resin (resin) and the like as necessary. This purification method is not particularly limited, and examples thereof include degreasing treatment, delignification treatment, and dehemicellulose treatment. As an example, there may be mentioned a method in which a cellulose-containing material is degreased with benzene-ethanol, then delignified with a Wise method, and dehemicellulose treated with an alkali.

As delignification treatment, in addition to the above Wise method, a method using peracetic acid (pa method), a method using a peracetic acid persulfuric acid mixture (pxa method), and the like are also used.
If necessary, bleaching treatment may be performed with chlorine, ozone, sodium hypochlorite, hydrogen peroxide, chlorine dioxide, or the like.

  Moreover, as a refinement | purification method, the manufacturing method of a general chemical pulp, for example, the manufacturing method of a kraft pulp, a sulfite pulp, an alkali pulp, and a nitrate pulp, is also mentioned. In addition, there is a method in which a cellulose-containing material is heat-treated in a digester to perform delignification or the like, and further a bleaching treatment or the like.

In the purification treatment, water is generally used as a dispersion medium. However, an aqueous solution of an acid or base or other treatment agent may be used, and in this case, it may be finally washed with water.
In addition, the cellulose-containing material may be crushed into a state such as a wood chip or wood powder, and this crushing may be performed at any timing before, during or after the purification treatment.

  In the purification treatment of the cellulose-containing material, an acid, a base, or other treatment agent is usually used, but the type is not particularly limited. For example, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium sulfide, magnesium sulfide, sodium sulfite, calcium sulfite, magnesium sulfite, ammonium sulfite, sodium sulfate, sodium thiosulfate, sodium oxide, oxidation Magnesium, calcium oxide, acetic acid, oxalic acid, sodium hypochlorite, calcium hypochlorite, sodium chlorite, sodium chlorate, chlorine dioxide, chlorine, sodium perchlorate, sodium thiosulfate, hydrogen peroxide, ozone Hydrosulfite, anthraquinone, dihydrodihydroxyanthracene, tetrahydroanthraquinone, anthrahydroquinone, alcohols such as ethanol, methanol, 2-propanol, and And water-soluble organic solvent such emissions and the like. These treatment agents may be used alone or in combination of two or more.

  Further, two or more purification treatments can be performed using two or more treatment agents. In that case, it is preferable to wash with water between purification treatments using different treatment agents.

  The temperature and pressure during the purification treatment are not particularly limited, and the temperature is preferably selected in the range of 0 ° C. or more and 100 ° C. or less. In the case of treatment under pressure exceeding 1 atm, the temperature is 100 ° C. or more and 200 ° C. The following is preferable.

<Cellulose fiber raw material>
Cellulose fibers obtained by purifying the cellulose-containing material are usually obtained in a water-containing state (aqueous dispersion). The cellulose fiber obtained by refining the cellulose-containing material may be hereinafter referred to as a cellulose fiber raw material.
Examples of the cellulose fiber raw material include hardwood kraft pulp, softwood kraft pulp, hardwood sulfite pulp, softwood sulfite pulp, hardwood bleached kraft pulp, softwood bleached kraft pulp, and linter pulp.

<Fiber diameter of cellulose fiber raw material>
The fiber diameter of the cellulose fiber raw material is not particularly limited, and the number average fiber diameter is preferably 10 μm to 100 mm, more preferably 50 μm to 0.5 mm from the viewpoint of defibration efficiency and handleability. preferable.
In order to obtain such a fiber diameter, for example, a mechanical treatment such as cutting or crushing may be performed on the cellulose-containing material. The mechanical treatment may be performed at any time before, during or after the purification treatment. For example, an impact pulverizer or a shear pulverizer may be used before the purification treatment, and a refiner or the like may be used during the purification treatment or after the treatment.
For example, when a chip or the like having a size of several centimeters is refined, it is preferable to perform a mechanical treatment with a disintegrator such as a refiner or a beater to make it about several mm.

  In the present invention, the method for measuring the number average fiber diameter of the cellulose fiber and the cellulose fiber raw material is not particularly limited, and is a scanning electron microscope (hereinafter SEM), a transmission electron microscope (hereinafter TEM), an atomic force microscope (hereinafter referred to as an atomic force microscope). AFM) or the like can be measured and obtained. For example, when measuring with a scanning electron microscope, after removing the solvent from the dispersion of the cellulose fiber to be measured, a line is drawn on the diagonal line of the SEM photograph, and 12 fibers are randomly extracted in the vicinity thereof, The average of 10 measured values from which the thickest fiber and the thinnest fiber are removed is the number average fiber diameter. It can measure similarly about the number average fiber length of a cellulose fiber.

<Modified cellulose fiber>
The cellulose fiber used in the present invention may be modified.
Hereinafter, modification of cellulose fibers will be described.

The modified cellulose fiber means a cellulose fiber in which a part of a hydroxyl group or hydroxymethyl group of cellulose constituting the cellulose fiber is substituted with another group.
Examples of the modification method include oxidation treatment and chemical modification treatment.
In addition, the process for this modification | denaturation may be performed with respect to a cellulose fiber raw material, and may be performed with respect to the cellulose fiber after the defibration process mentioned later.

  Carboxy groups can be introduced into cellulose by performing an oxidation treatment. As the oxidation treatment, the cellulose fiber raw material or the cellulose fiber is brought into contact with an oxidizing gas (hereinafter referred to as “oxidizing gas”), or the cellulose fiber raw material or the cellulose fiber is suspended in a solution containing an oxidizing chemical species. The method of immersing can be mentioned.

  Although it does not specifically limit as oxidizing gas, Ozone, chlorine gas, fluorine gas, chlorine dioxide, nitrous oxide, etc. are mentioned, These 2 or more types may be included.

  As the oxidizing chemical species, a reagent that can oxidize alcohol to an aldehyde or carboxylic acid can be generally used, and is not particularly limited. However, a hexavalent chromic acid sulfuric acid mixture, Jones reagent (chromic anhydride (Sulfuric acid solution), chromic acid oxidizing reagents such as pyridinium chlorochromate (PCC reagent), activated dimethyl sulfoxide reagent used for Swern oxidation, and tetrapropylammonium perruthenad (catalytic oxidation) TPAP) and N-oxyl compounds such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) (Japanese Patent Laid-Open No. 2008-1728).

Examples of the chemical modification treatment include treatment for introducing the group described below.
For example, acetyl group, acryloyl group, methacryloyl group, propionyl group, propioroyl group, butyryl group, 2-butyryl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, nonanoyl group, decanoyl group, undecanoyl group, dodecanoyl group, myristoyl Group, palmitoyl group, stearoyl group, pivaloyl group, benzoyl group, naphthoyl group, nicotinoyl group, isonicotinoyl group, furoyl group, acyl group such as cinnamoyl group; isocyanate group such as 2-methacryloyloxyethylisocyanoyl group; methyl group, ethyl Group, propyl group, 2-propyl group, butyl group, 2-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, milli Oxirane group; an oxetane group, a thiirane group; thietane group; a carboxylic acid group; methyl group, palmityl group, an alkyl group such as a stearyl group and a phosphoric acid group.
Moreover, the hydrogen atom in these substituents may be substituted with a functional group such as a hydroxyl group or a carboxy group. Further, a part of the alkyl group may be an unsaturated bond. Moreover, the 2 or more types of substituent of these groups may be introduce | transduced into the cellulose fiber.

  Among these substituents, an acyl group having 2 to 12 carbon atoms such as an acetyl group, an acryloyl group, a methacryloyl group, a benzoyl group and a naphthoyl group is preferable, and an acetyl group is particularly preferable.

These substituents can be introduced by reacting the cellulose fiber raw material or cellulose fiber with the following chemical modifier.
Examples of the chemical modifier include one or more selected from the group consisting of acids, acid anhydrides, alcohols, halogenating reagents, and cyclic ethers such as isocyanates, alkoxysilanes, and oxiranes (epoxies). Can be mentioned.

Examples of the acid include acetic acid, acrylic acid, methacrylic acid, propanoic acid, butanoic acid, 2-butanoic acid, and pentanoic acid.
Examples of the acid anhydride include acetic anhydride, acrylic anhydride, methacrylic anhydride, propanoic anhydride, butanoic anhydride, 2-butanoic anhydride, and pentanoic anhydride.
Examples of the halogenating reagent include acetyl halide, acryloyl halide, methacryloyl halide, propanoyl halide, butanoyl halide, 2-butanoyl halide, pentanoyl halide, benzoyl halide and naphthoyl halide.
Examples of the alcohol include methanol, ethanol, propanol, and 2-propanol.
Examples of the isocyanate include methyl isocyanate, ethyl isocyanate and propyl isocyanate.
Examples of the alkoxysilane include methoxysilane and ethoxysilane.
Examples of cyclic ethers such as oxirane (epoxy) include ethyl oxirane and ethyl oxetane.

Among these, acetic anhydride, acrylic anhydride, methacrylic anhydride, benzoyl halide or naphthoyl halide is particularly preferable.
These chemical modifiers may be used alone or in combination of two or more.

  Chemical modification can be performed by a known method. That is, it can be carried out by reacting a cellulose fiber raw material or a cellulose fiber whose fiber length or fiber diameter is adjusted with a chemical modifier according to a conventional method. At this time, a solvent or a catalyst may be used as necessary, and heating, decompression, or the like may be performed.

  In addition, when using a cellulose fiber raw material, since this cellulose fiber raw material is a water-containing state normally, it is preferable to replace this water with the reaction solvent and to suppress reaction of a chemical modifier and water as much as possible. In addition, when the raw material is dried to remove water, it is difficult to make the raw material finer in the defibrating process described later, and therefore it is not preferable to include a drying step.

  The amount of the chemical modifier is not particularly limited, and varies depending on the type of the chemical modifier, but is preferably 0.01 times or more, more preferably 0.05 times or more, more preferably 100 times the number of moles of the hydroxyl group of cellulose. The following is preferable, and 50 times or less is more preferable.

  As the solvent, a water-soluble organic solvent that does not inhibit chemical modification is preferably used. Examples of the water-soluble organic solvent include organic solvents such as acetone and pyridine, and organic acids such as formic acid, acetic acid, and succinic acid, and organic acids such as acetic acid are particularly preferable. By using an organic acid such as acetic acid, the chemical modification progresses uniformly to the cellulose, so that it will be easy to defibrate as described later, and the resulting thermosetting resin molding will exhibit high heat resistance and high productivity. It is done. Moreover, you may use things other than the said solvent together.

  The amount of the solvent used is not particularly limited, but is usually preferably 0.5 times or more, more preferably 1 times or more, more preferably 200 times or less, and more preferably 100 times or less the weight of cellulose. preferable.

  As the catalyst, it is preferable to use a basic catalyst such as pyridine, triethylamine, sodium hydroxide or sodium acetate, or an acidic catalyst such as acetic acid, sulfuric acid or perchloric acid. The amount of the catalyst is not particularly limited and varies depending on the type, but is usually preferably 0.01 mol times or more, more preferably 0.05 mol times or more, and more preferably 100 mol times or less, relative to the number of moles of the hydroxyl group of cellulose. Is preferable, and 50 mole times or less is more preferable.

  The temperature condition is not particularly limited, but if it is too high, there are concerns about yellowing of cellulose, a decrease in the degree of polymerization, etc., and if it is too low, the reaction rate decreases, so 10 to 130 ° C. is preferable. The reaction time is not particularly limited, and is usually from several minutes to several tens of hours depending on the chemical modifier and the chemical modification rate.

  After performing chemical modification in this manner, it is preferable to sufficiently wash with an organic solvent or water in order to terminate the reaction. It is not preferable that the unreacted chemical modifier remains, since it may cause coloring later or become a problem when combined with a resin.

  The modification ratio of the modified cellulose fiber used in the present invention (the amount of other groups introduced into the cellulose fiber) is a modification rate calculated by the method described later, and is usually 3 to 70 mol%. Preferably, when it has two or more kinds of groups, it is preferable that the above range is satisfied in total.

  Increasing the amount of other groups introduced into the cellulose fiber is preferable in terms of improving the dispersibility of the cellulose fiber in the solvent and the interfacial adhesion to the resin, but if the amount introduced is greater than the above upper limit, the cellulose There is a risk that the crystallinity of the glass will decrease and the effect of reducing linear thermal expansion will be impaired.

  Here, the modification | denaturation rate of a cellulose fiber can be calculated | required as follows.

0.05 g of the dried modified cellulose fiber is precisely weighed, and 1.5 ml of ethanol and 0.5 ml of distilled water are added thereto. This is left to stand in a hot water bath at 60 to 70 ° C. for 30 minutes, and then 2 ml of 0.5N aqueous sodium hydroxide solution is added. After leaving this in a 60-70 degreeC hot water bath for 3 hours, it ultrasonically shakes for 30 minutes with an ultrasonic cleaner. This is titrated with 0.1N hydrochloric acid standard solution using phenolphthalein as an indicator.
Here, from the amount Z (ml) of the 0.1N aqueous hydrochloric acid solution required for the titration, the number of moles Q of the substituent introduced by modification can be obtained by the following formula.
Q (mol) = 0.5 (N) × 2 (ml) / 1000
−0.1 (N) × Z (ml) / 1000
The relationship between the number of moles Q of the substituent and the modification rate X (mol%) is calculated by the following formula (cellulose = (C ₆ O ₅ H ₁₀ ) _n = (162.14) _n , repeating unit. Number of hydroxyl groups per unit = 3, molecular weight of OH = 17). In the following, T is the molecular weight of a substituent introduced by modification.

  Solving this, it is as follows.

In addition, the introduction amount to the cellulose fiber of a carboxy group can also be calculated | required with the following method using TAPPI T237 cm-08 (2008).
Specifically, in order to make it possible to calculate the introduction number of acidic groups (here, carboxy groups) over a wider range, among the test solutions used in the test method, sodium bicarbonate (NaHCO ₃ ) / sodium chloride (NaCl) = 0.84 g / 5.85 g of the test solution dissolved in 1000 ml with distilled water, sodium bicarbonate / sodium chloride = 3.36 g / 23.23 so that the concentration of the test solution is substantially quadrupled. The amount is calculated according to TAPPI T237 cm-08 (2008) except that the difference is 40 g, and the difference between the calculated values of the cellulose fibers before and after the introduction of the substituent is the substantial amount of substituent introduced.

<Adjustment of fiber length and fiber diameter>
The number average fiber diameter of the cellulose fiber used in the present invention is preferably 400 nm or less. The number average fiber diameter of the cellulose fibers is more preferably 100 nm or less, further preferably 80 nm or less, particularly preferably 50 nm or less, particularly preferably 30 nm or less, and most preferably 20 nm or less. Further, the number average fiber diameter of the cellulose fibers is preferably as small as possible. However, in order to achieve a high effect, it is important to maintain the crystallinity of the cellulose, and is preferably 2 nm or more, substantially cellulose crystals. It is more preferable that the unit fiber diameter is 4 nm or more. When the number average fiber diameter of the cellulose fibers exceeds the above upper limit, the specific surface area of the cellulose fibers becomes small, and a sufficient linear thermal expansion reduction effect may not be obtained. When the average fiber diameter of the cellulose fiber is lower than the above lower limit, the I-type crystal structure of cellulose cannot be maintained, and the strength of the fiber itself may decrease.

  The number average fiber length of the cellulose fibers may be 1 μm or less, but is preferably 950 nm or less, more preferably 900 nm or less, particularly preferably 850 nm or less, and usually 10 nm or more, preferably 50 nm or more.

(solvent)
By subjecting the above-mentioned cellulose fiber raw material to the following defibrating treatment, the fiber length and fiber diameter can be adjusted as in the above ranges. The defibrating process is to unravel the fibers, and usually the fibers can be made smaller.

  The cellulose fiber used in the present invention may be defibrated either in water or in an organic solvent. However, since it is suitable for mixing a resin, it is preferably defibrated in an organic solvent. Usually, since the cellulose fiber raw material is dispersed in water, in this case, it is preferable to perform the defibrating treatment after replacing water with an organic solvent.

The method for substituting the solvent is not particularly limited, but the water is removed from the aqueous dispersion of the cellulose fiber raw material by filtration, etc., and the organic solvent used at the time of defibration is added thereto, mixed with stirring, and the organic solvent is again filtered. The method of removing is mentioned. By repeating the addition of organic solvent and filtration, the medium in the dispersion can be replaced with water from the organic solvent.
In addition, when the organic solvent to be used is water-insoluble, after substituting with a water-soluble organic solvent once, you may substitute with a water-insoluble organic solvent.

  Here, examples of the organic solvent include aromatic hydrocarbon solvents, alcohol solvents, ketone solvents, aprotic polar solvents, ether solvents (including glycol ether solvents), and the like.

  Preferred examples of the aromatic hydrocarbon solvent include aromatic hydrocarbons having 6 to 12 carbon atoms, and specific examples include benzene, toluene, xylene and the like.

  The alcohol solvent is preferably an alcohol solvent having 1 to 7 carbon atoms, specifically, methanol, ethanol, propanol, butanol and the like.

The ketone solvent (referring to a liquid having a ketone group) is preferably a ketone solvent having 3 to 9 carbon atoms, specifically, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisopropyl. Examples include ketone, di-tert-butyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclopentanone, cyclohexanone, cyclohexyl methyl ketone, acetophenone, acetylacetone, and dioxane.
As aprotic polar solvents, sulfoxide solvents such as dimethyl sulfoxide (DMSO), formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, 2-pyrrolidone And amide solvents such as N-methylpyrrolidone.

Examples of ether solvents include diethyl ether and tetrahydrofuran. Preferred examples of the glycol ether solvent include glycol ether solvents having 3 to 9 carbon atoms. Specific examples include ethylene glycol mono-tert-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono -N-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol mono- n-butyl ether, propylene Recalls monomethyl ether acetate.
These organic solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  In addition, since the organic solvent used by this invention has the process of removing an organic solvent in the manufacturing process of a fiber resin molding, it is preferable that a boiling point is not too high. The boiling point of the organic solvent is preferably 300 ° C. or less, preferably 200 ° C. or less, and more preferably 180 ° C. or less. In view of handling properties, the organic solvent preferably has a boiling point of 0 ° C. or higher. In particular, MEK and cyclohexanone are preferable from the viewpoint of solubility of the curable resin and / or curable resin precursor described below. In addition, when using together MEK and cyclohexanone, it is preferable that the use ratio shall be MEK: cyclohexanone = 1: 0.01-100 (weight ratio).

(Defibration method)
The specific method of the defibrating step is not particularly limited, and examples thereof include a defibrating process by a bead mill, a defibrating process by jetting, a defibrating process by a rotary defibrating method, or a defibrating process by ultrasonic treatment. .

  Among the defibrating treatments, the treatment with a bead mill has high defibrating efficiency and is effective in improving the dispersibility of cellulose fibers.

  In the case of defibration by these treatments, the solid content concentration (cellulose fiber raw material concentration) in the raw material dispersion is not particularly limited, but is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and 99% by weight. % Or less is preferable, and 50% by weight or less is more preferable. If the solid content concentration in the raw material dispersion used for the defibrating process is too low, the amount of liquid will be excessive with respect to the amount of cellulose fiber raw material to be treated, and the efficiency will be poor, and if the solid content concentration is too high, the fluidity will be poor. .

  In addition, you may contain the curable resin and / or curable resin precursor which are explained in full detail below in the raw material dispersion liquid used for a fibrillation process. In that case, the cellulose fiber raw material is defibrated together with the curable resin and / or the curable resin precursor, thereby suppressing the aggregation of the cellulose fiber raw material and increasing the defibrating efficiency.

  In this case, the content of the curable resin and / or curable resin precursor in the raw material dispersion is usually 0.1% by weight or more, preferably 0.2% by weight or more, and usually 99% by weight or less, preferably Is 80% by weight or less, more preferably 70% by weight or less, and the content of the cellulose fiber raw material is usually 0.1% by weight or more, preferably 0.2% by weight or more, usually 99% by weight or less, preferably 80%. The total content of the cellulose fiber raw material and the curable resin and / or curable resin precursor is usually 0.1% by weight or more, preferably 0.2% or less. % By weight or more, usually 99% by weight or less, preferably 80% by weight or less, more preferably 70% by weight or less.

  When these contents exceed the above upper limit, the fluidity is deteriorated. If the content of the curable resin and / or curable resin precursor is below the lower limit, the effect of suppressing fiber aggregation may not be obtained. Moreover, when content of a cellulose fiber raw material is less than the said lower limit, there is little quantity of the cellulose fiber raw material provided to defibration, and there exists a possibility that processing efficiency may worsen.

  As the defibrating process using a bead mill, for example, ceramic beads having a diameter of about 1 mm are placed in a raw material dispersion having a cellulose fiber raw material concentration of 0.5 to 50% by weight, specifically about 1% by weight, and then a paint shaker or bead mill. For example, a method of defibrating by applying vibration using the like.

  As the bead mill, known devices can be used. For example, Ultra Apex Mill UAM, Dual Apex Mill DAM (both manufactured by Kotobuki Industries), Star Mill (manufactured by Ashizawa Finetech), OB Mill (manufactured by Turbo Industry) Etc.

  The material of the beads used is not particularly limited, and examples thereof include glass and zirconia. The particle size of the beads is not particularly limited, and is usually about 0.01 to 5 mm in diameter. The conditions for performing the bead mill are appropriately selected according to the materials used, such as the type of solvent and the fiber diameter of the intended cellulose fiber, but are usually 1 to 4 at a peripheral speed of 4 to 16 m / sec. It is preferable to carry out for about 5 hours. In addition, when performing defibration with a bead mill, it may be performed a plurality of times under different conditions.

  In addition, as a kind of media mill, there is a method of defibrating fibers using a rotating main shaft and a counter shaft and a ring rotating in conjunction with the rotation of the main shaft as a grinding medium.

  In addition, shearing between cellulose fibers by blending with a blender type disperser or slits rotating at high speed by applying shear force through the raw material dispersion (high speed rotating homogenizer) or by suddenly reducing pressure from high pressure. Examples thereof include a method of generating force by defibration (high-pressure homogenizer method), a method using a counter-impact type disperser (Masuko Sangyo) such as Massomizer X, and the like.

  Specific examples of the defibrating process by jetting include defibrating with a high-pressure homogenizer. In the case of a high-pressure homogenizer, the raw material dispersion is preferably pressurized to 30 MPa or more, more preferably 100 MPa or more, still more preferably 150 MPa or more, particularly preferably 220 MPa or more with a pressure intensifier, and ejected from a nozzle having a pore diameter of 50 μm or more. The pressure is reduced so that the difference is preferably 30 MPa or more, more preferably 80 MPa or more, and further preferably 90 MPa or more. The cellulose fiber is defibrated by the cleavage phenomenon caused by this pressure difference.

Here, when the pressure under the high pressure condition is low, or when the pressure difference from the high pressure to the decompression condition is small, the defibrating efficiency is lowered, and it is necessary to increase the number of repeated ejections to obtain a desired fiber diameter. Absent.
The higher the high pressure condition at the time of jetting, the more cleavage can be achieved by a large cleavage phenomenon due to the pressure difference, but the upper limit of the apparatus specification is usually 245 MPa or less.

  Similarly, it is preferable that the pressure difference from the high pressure condition to the reduced pressure is large, but generally, the upper limit of the pressure difference is usually 245 MPa or less by ejecting from the pressurizing condition by the pressure intensifier to the atmospheric pressure. .

  In addition, when the pore diameter of the pores from which the raw material dispersion is ejected is too large, a sufficient defibrating effect cannot be obtained. In this case, even if the ejection treatment is repeated, cellulose having a desired fiber diameter is obtained. There is also a possibility that fibers cannot be obtained. If the diameter of the pores through which the raw material dispersion is ejected is small, a high-pressure state can be easily created, but if it is too small, the ejection efficiency is deteriorated. The pore diameter is preferably 50 μm or more, more preferably 100 μm or more, further preferably 150 μm or more, preferably 800 μm or less, more preferably 500 μm or less, and even more preferably 350 μm or less.

  The ejection of the raw material dispersion is repeated a plurality of times as necessary, thereby increasing the degree of fineness and obtaining cellulose fibers having a desired fiber diameter. The number of repetitions (pass number) is usually 1 or more, preferably 3 or more, and usually 20 or less, preferably 15 or less. As the number of passes increases, the degree of miniaturization can be increased. However, an excessively large number of passes is not preferable because the cost increases.

  Although there is no restriction | limiting in particular in the temperature (dispersion liquid temperature) at the time of ejection, Usually, it is 5 to 100 degreeC. If the temperature is too high, there is a possibility that the apparatus, specifically, the liquid feed pump, the high-pressure seal part, and the like may be deteriorated, which is not preferable.

  One or two ejection nozzles may be used, and the ejected raw material dispersion may be hit against a wall, ball, or ring provided at the ejection destination. Furthermore, when there are two nozzles, the raw material dispersions may collide with each other at the ejection destination.

  Although the specific apparatus of a high pressure homogenizer is not restrict | limited in particular, For example, the "starburst system" by a Gaulin company or a Sugino machine company can be used.

  In addition, it is possible to obtain a fine cellulose fiber dispersion used in the present invention only by treatment with such a high-pressure homogenizer, but when the treatment efficiency is poor with a large number of repetitions for obtaining a sufficient fineness. It is preferable to refine by performing the following ultrasonic treatment after the high-pressure homogenizer treatment about 1 to 5 times. Moreover, the process by a high pressure homogenizer can also be performed as a preliminary | backup dispersion | distribution process prior to the defibration process by the above-mentioned bead mill.

  Specific examples of the defibrating process using the rotary defibrating method include defibrating with a high-speed rotating homogenizer. In the case of a high-speed rotation homogenizer, the higher the number of rotations, the higher the rotational speed and the higher the defibration efficiency. As a rotation speed, for example, 10,000 rpm or more is preferable, 15000 rpm or more is more preferable, and 20000 rpm or more is particularly preferable. The upper limit of the rotational speed is not particularly limited, but is preferably 30000 rpm or less from the viewpoint of the performance of the apparatus.

The treatment time is preferably 1 minute or longer, more preferably 5 minutes or longer, and particularly preferably 10 minutes or longer. The treatment time is preferably 6 hours or less from the viewpoint of productivity. When heat is generated by shearing, it is preferable to cool the solution so as not to exceed 50 ° C.
Further, it is preferable to stir or circulate so that the raw material dispersion is uniformly sheared.
The defibrating process by the rotary defibrating method may be performed as a pretreatment of the defibrating process by the bead mill described above.

  In the case of performing defibration treatment by ultrasonic treatment, the cellulose concentration in the raw material dispersion liquid after defibration treatment that is subjected to ultrasonic treatment (hereinafter referred to as the ultrasonic treatment raw material dispersion liquid) is relative to the total amount of the liquid. 0.5 wt% or more is preferable, 1 wt% or more is more preferable, 50 wt% or less is preferable, and 40 wt% or less is more preferable. If the cellulose concentration in the ultrasonic treatment raw material dispersion for irradiating ultrasonic waves is too low, it is inefficient, and if it is too high, the viscosity increases and the defibrating treatment may become uneven.

  In the defibrating process, the raw material dispersion is accelerated to the speed of sound with compressed air, water droplets are made to collide with the collision plate, and a shock wave is generated in the liquid film on the inside of the droplet and the surface of the collision plate, thereby crushing and dispersing the particles A droplet collision method can be used. As an apparatus for this purpose, for example, a wet grinder “G-smasher” manufactured by Rix Co., Ltd. may be mentioned.

  After the above-described defibrating treatment, the cellulose fiber dispersion may be filtered using a pressure filter or the like to remove cellulose fibers with poor defibration.

<Enzyme treatment>
When manufacturing the cellulose fiber used by this invention, you may perform an enzyme process prior to the above-mentioned defibration process.
The enzyme treatment is performed using a cellulase enzyme that cleaves the β-1,4-glucoside bond of cellulose by hydrolysis and causes depolymerization, and the cellulose fiber raw material is fibrillated by the enzyme treatment to obtain the fiber diameter and fiber length. Can be reduced.
The enzyme treatment is usually performed by adding a cellulase enzyme to an aqueous dispersion of cellulose fiber raw material.

  Cellulase-producing microorganisms include aerobic bacteria, anaerobic bacteria, rumen bacteria, actinomycetes, yeast, filamentous fungi (ascomycetes, basidiomycetes, etc.) present in the digestive organs of animals and insects. Produces a novel cellulase.

  Cellulase-based enzymes include the genus Trichoderma, the genus Acremonium, the genus Aspergillus, the genus Phanerochaete, the trametes, Trametes, Genus, Humicola (filamentous fungus) genus, Bacillus (bacteria) genus, Suehirotake (Basidiomycetes) genus, Streptomyces (bacteria) genus, Pseudomonas (cellulosae) genus Pseudomonas Enzymes. Such a cellulase enzyme can be purchased as a reagent or a commercial product. Examples thereof include cellulosin T2 (manufactured by HIPI), mecerase (manufactured by Meiji Seika Co., Ltd.), Novozyme 188 (manufactured by Novozyme), multifect CX10L (manufactured by Genencor), cellulase enzyme GC220 (manufactured by Genencor). Among these cellulase enzymes, filamentous fungal cellulase enzymes are preferred, and among the filamentous fungal cellulase enzymes, cellulase enzymes produced by Trichoderma bacterium (Trichoderma reesei or Hyporea jerorina) are cellulase enzymes. It is particularly preferred because of its wide variety of enzymes and high productivity. Further, it may be used by mixing with the following hemicellulase enzymes.

  A hemicellulase-based enzyme is an enzyme that hydrolyzes hemicellulose. Among hemicellulase-based enzymes, xylanase, which is an enzyme that degrades xylan, mannanase, which is an enzyme that degrades mannan, and arabanase, an enzyme that degrades araban. In addition, pectinase, which is an enzyme that degrades pectin, can also be used as a hemicellulase-based enzyme. Microorganisms that produce hemicellulase enzymes often also produce cellulase enzymes.

  Hemicellulose is a polysaccharide excluding pectins between cellulose microfibrils in the plant cell wall. Hemicelluloses are diverse and differ between plant types and cell wall layers. In wood, glucomannan is the main component in the secondary wall of conifers, and 4-O-methylglucuronoxylan is the main component in the secondary walls of hardwood. Therefore, in order to obtain fine fibrous cellulose from conifers, it is preferable to use mannase, and in the case of hardwoods, it is preferable to use xylanase.

  The amount of cellulase enzyme added to the cellulose fiber raw material is preferably 0.1 to 3% by weight, and more preferably 0.3 to 2.5% by weight. If the addition amount of the cellulase enzyme is less than 0.1% by weight, the fibrillation efficiency by the enzyme may be reduced. If the addition amount exceeds 3% by weight, the cellulose is saccharified and the yield of fine cellulose fibers is reduced. There is a risk.

  The pH of the aqueous dispersion of cellulose fiber raw material during the cellulase enzyme treatment is preferably a weakly acidic region of pH 3.0 to 6.9, but an optimal pH region may be appropriately selected depending on the type of cellulase enzyme.

  Further, the pH of the aqueous dispersion of the cellulose fiber raw material when the treatment with the hemicellulase-based enzyme is preferably pH 7.1 to 10.0 which is a weak alkaline region, but the optimum pH region depending on the type of the hemicellulase-based enzyme. May be selected.

  The temperature of the aqueous dispersion of the cellulose fiber raw material during the enzyme treatment is preferably 30 to 70 ° C, more preferably 35 to 65 ° C, and particularly preferably 40 to 60 ° C. If the temperature is less than 30 ° C., the enzyme activity decreases and the treatment time becomes longer, which is not preferable. If the temperature exceeds 70 ° C., the enzyme is deactivated, which is not preferable. The treatment time is adjusted by the enzyme type, temperature, and pH, but preferably 30 minutes to 24 hours. If the treatment time is less than 30 minutes, the effect of the enzyme treatment may hardly be exhibited. If it exceeds 24 hours, the decomposition of the cellulose fibers proceeds too much by the enzyme, and the number average fiber length of the obtained fine cellulose fibers may be too short.

  If the enzyme remains active, the decomposition of the cellulose fiber proceeds too much. Therefore, an aqueous sodium hydroxide solution of about 20% by weight is added to the aqueous dispersion of the cellulose fiber raw material after the reaction with the enzyme for a predetermined time. Usually, the enzyme is deactivated by adding the dispersion so that the pH is about 12, or the temperature of the aqueous dispersion of the cellulose fiber raw material is increased to 90 ° C. to deactivate the enzyme. Although it is simpler to add a sodium hydroxide aqueous solution, dehydration may be deteriorated in the subsequent cleaning treatment, and it is necessary to deal with it. Washing with water may be carried out with 2 to 4 times the amount of water of cellulose fibers, so that almost no enzyme remains.

[Curable resin]
Next, the curable resin and / or curable resin precursor used in the present invention will be described.

  The curable resin and / or curable resin precursor is not particularly limited. For example, an epoxy resin, an acrylic resin, an alcohol resin, an amide resin, an ether resin, an amine resin, an aromatic resin, an oxetane resin, Examples thereof include phenol resins, urea resins, melamine resins, unsaturated polyester resins, silicon resins, polyurethane resins, diallyl phthalate resins, thermosetting polyimide resins, and precursors thereof, cellulose derivatives, and the like. A curable resin and / or a curable resin precursor may be used individually by 1 type, and 2 or more types may be mixed and used for them.

(Epoxy resin / epoxy resin precursor)
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenol type epoxy resin, bisphenol AD type epoxy resin, bisphenol acetophenone type epoxy resin, bisphenol fluorenone type epoxy resin, and the like. Type epoxy resin, diglycidyl ether type epoxy resin of monocyclic dihydric phenol such as catechol, resorcin, hydroquinone, dihydroxy naphthalene type epoxy resin, dihydroxy dihydroanthracene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin , Glycidyl ether type epoxy resins such as bisphenol A novolac type epoxy resin, glycidyl ester Le epoxy resin, glycidyl amine type epoxy resins, linear aliphatic epoxy resins, alicyclic epoxy resins, various epoxy resins such as heterocyclic epoxy resins.
These epoxy resins may be substituted with a substituent such as an alkyl group, an aryl group, an ether group, or an ester group within a range that does not affect the effects of the present invention.

  Among these epoxy resins, particularly preferable ones are bisphenol A type epoxy resins, bisphenol F type epoxy resins, crystalline resins which are easy to handle, and 4,4′-biphenol type epoxy resins which have a low viscosity above the melting point. , 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol type epoxy resin, phenolic novolac that is polyfunctional and has a high crosslink density upon curing and a cured product having high heat resistance Type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin and the like.

  The epoxy resin can be used from a monomer type having a low weight average molecular weight (Mw) (for example, Mw = 200) to a polymer type having a high molecular weight (for example, Mw = 90,000). When the weight average molecular weight is 100,000 or more, it becomes difficult to handle the resin, which is not preferable. From the viewpoint of the handleability of the resin, the weight average molecular weight of the epoxy resin is preferably 200 or more, more preferably 300 or more, preferably 80,000 or less, and more preferably 60,000 or less.

Examples of the epoxy resin precursor include divalent phenols, and any epoxy resin precursor may be used as long as a hydroxyl group is bonded to an aromatic ring. For example, bisphenols such as bisphenol A, bisphenol F, bisphenol B, bisphenol AD, 4,4′-biphenol, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol, biphenol, catechol, resorcin , Hydroquinone, dihydroxynaphthalene and the like.
Examples of the epoxy resin precursor include those in which these dihydric phenols are substituted with non-interfering substituents such as an alkyl group, an aryl group, an ether group, and an ester group.

  Among these dihydric phenols, preferred are bisphenol A, bisphenol F, 4,4'-biphenol, 3,3 ', 5,5'-tetramethyl-4,4'-biphenol. These dihydric phenols can be used in combination.

  In addition to dihydric phenols, polyfunctional phenol resins may be mentioned, such as phenol novolac resins, bisphenol novolac resins, dicyclopentadiene phenol resins, Xylok phenol resins, terpene modified phenol resins, melamine modified phenol novolac resins. And a triazine structure-containing novolac resin.

(Acrylic resin / acrylic resin precursor)
Examples of the acrylic resin include polymers and copolymers such as (meth) acrylic acid, (meth) acrylonitrile, (meth) acrylic acid ester, and (meth) acrylamide. Among these, (meth) acrylic acid, polymers and copolymers of (meth) acrylic acid esters, and the like are preferable. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid, and the same applies to (meth) acrylonitrile and (meth) acrylamide.

  The weight average molecular weight of the acrylic resin is not particularly limited, but is preferably 300 or more, more preferably 400 or more, preferably 3,000,000 or less, and more preferably 2,500,000 or less from the viewpoint of handleability.

  Examples of the acrylic resin precursor include (meth) acrylic acid, (meth) acrylonitrile, (meth) acrylic acid ester, (meth) acrylamide, and the like. Of these, (meth) acrylic acid, (meth) acrylic acid ester and the like are preferable.

(Alcohol-based resin)
Examples of the alcohol resin include polyethylene glycol, polyether polyol, polyester polyol, polyvinyl alcohol, amylose, amylopectin, sorbitol, polycaprolactone, polyvalerolactone, polybutyrolactone, polyglycol, and polylactic acid.

(Amide resin)
Examples of the amide resin include polyacrylamide, chitin, chitosan, polyvinyl pyrrolidone, and polycaprolactam.

(Ether resin)
Examples of the ether resin include crown ether, polyethylene glycol, polypropylene glycol and the like.

(Amine resin)
Examples of the amine-based resin include polyallylamine, polylysine, various amine-modified acrylic copolymers, and the like.

(Aromatic resin)
Examples of the aromatic resin include polyphenylene oxide, catechin, tannin, terpene and the like.

  Among these, alcohol resins and amide resins are preferable, and polyvinyl alcohol and polyvinyl pyrrolidone are particularly preferable.

(Cellulose derivative)
Examples of the cellulose derivative include cellulose diacetate, cellulose triacetate, and other cellulose organic acid esters such as acetylcellulose, cellulose acetate propionate, and cellulose acetate butyrate with an appropriately adjusted degree of acetylation. Examples of the cellulose ether include alkyl cellulose, hydroxyalkyl cellulose, and cellulose ether having an ionic substituent. Examples of the alkyl cellulose include methyl cellulose and ethyl cellulose. Examples of the hydroxyalkyl cellulose include hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose and the like. Examples of the cellulose ether having an ionic substituent include carboxymethyl cellulose.

[Fiber dispersion]
In this invention, the fiber dispersion formed into a film on a board | substrate contains the said cellulose fiber and said curable resin and / or curable resin precursor.

  The fiber dispersion may be produced by adding the above-described curable resin and / or curable resin precursor to the cellulose fiber dispersion obtained by the above-described defibrating treatment, or the cellulose fiber raw material or curable resin. It may also be produced by subjecting a raw material dispersion containing a curable resin precursor and a solvent to a defibrating treatment.

  The content of the cellulose fiber in the solid content of the fiber dispersion is 15% by weight or more, preferably 20% by weight or more, more preferably 25% by weight or more, further preferably 30% by weight or more, and usually 90% by weight or less. , Preferably 80% by weight or less, more preferably 70% by weight or less. If the cellulose fiber content is below the lower limit, the effect of reducing the linear expansion coefficient by the cellulose fiber may be insufficient, and a low linear expansion fiber resin molded product may not be obtained. In addition, the bonding between the fibers by the resin or the filling of the spaces between the fibers is not sufficient, and the strength, transparency, and surface flatness of the obtained fiber resin molding may be deteriorated.

  The content of the curable resin and / or curable resin precursor in the solid content of the fiber dispersion is usually 10% by weight or more, preferably 20% by weight or more, more preferably 30% by weight or more, and still more preferably 40%. % By weight or more, usually 85% by weight or less, preferably 80% by weight or less, more preferably 75% by weight or less. If the content of the curable resin and / or curable resin precursor is below the above lower limit, the adhesion between the fibers by the resin or the filling of the spaces between the fibers is not sufficient, and the strength and transparency of the resulting fiber resin molding The surface flatness may be lowered, and if the upper limit is exceeded, the cellulose fiber content is relatively reduced. Therefore, the effect of reducing the linear expansion coefficient by the cellulose fiber is insufficient, and the low linear expansion fiber. There are cases where a resin molded body cannot be obtained.

  In this fiber dispersion, the content ratio (weight ratio) of the cellulose fiber and the curable resin and / or curable resin precursor is preferably in the range of 15:85 to 99: 1. When the content ratio of the cellulose fiber and the curable resin and / or the curable resin precursor is within this range, a fiber resin molded body having a sufficiently low linear expansion can be obtained. The content ratio (weight ratio) of the cellulose fiber and the curable resin and / or curable resin precursor in the fiber dispersion is more preferably in the range of 20:80 to 95: 5, and further preferably 25:75 to 90. : 10 range.

  In addition, in the fiber dispersion used by this invention, the below-mentioned various additives other than a cellulose fiber, curable resin, and / or curable resin precursor may be contained as needed. In any case, the solid content in the fiber dispersion is not particularly limited, but is preferably 1% by weight or more, more preferably 2% by weight or more, particularly preferably 3% by weight or more, and preferably 99% by weight or less, 95 weight% or less is more preferable, and 90 weight% or less is especially preferable. If the solid content of the fiber dispersion exceeds the above upper limit, the fluidity of the dispersion may decrease and film formation on the substrate may not be possible. It may not be preferable.

The fiber dispersion usually contains a solvent. Examples of the solvent include water and organic solvents described as solvents used in the defibrating process.
The content of the solvent in the fiber dispersion is preferably 1% by weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, preferably 99% by weight or less, more preferably 98% by weight or less, Preferably it is 95 weight% or less. If the content of the solvent in the fiber dispersion is below the lower limit, the fluidity of the fiber dispersion is lowered and film formation becomes difficult.If the content exceeds the upper limit, the film thickness at the time of film formation becomes thin, and in terms of productivity. It may not be preferable.

The fiber dispersion used in the present invention contains a chain transfer agent, an ultraviolet absorber, a filler, a silane coupling agent, a photo / thermal polymerization initiator, a curing agent, a curing accelerator and the like as necessary. Also good. These may be allowed to coexist during the defibrating process, or may be added after the defibrating process.
In addition, when using an epoxy resin and / or its precursor as curable resin and / or a curable resin precursor, an epoxy resin hardening | curing agent can also be used together.

  The epoxy resin curing agent to be used is not particularly limited, and for example, polyphenol compounds, amine compounds, acid anhydrides and the like exemplified below can be used.

  For example, bisphenol A, bisphenol F, bisphenol AD, hydroquinone, resorcin, methylresorcin, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, thiodiphenols, phenol novolac resin, cresol novolac resin, phenol aralkyl resin, terpene phenol resin Various polyphenols such as dicyclopentadienephenol resin, bisphenol A type novolak resin, naphthol novolak resin, biphenylphenol resin, brominated bisphenol A, brominated phenol novolak resin, various phenols and benzaldehyde, hydroxybenzaldehyde , Crotonaldehyde, glyoxal and other aldehydes Polyphenolic resins obtained by reaction, various phenol resins such as heavy oil or pitch, phenols and formaldehydes co-condensation resins, and phenolic hydroxyl groups of these various phenols (resins) Active ester compounds obtained by esterifying all or part of them, such as benzoate or acetate, and acid anhydrides such as methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, methylnadic acid And amines such as diethylenetriamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, dicyandiamide, aliphatic polyamine, and polyamide.

Cationic polymerization initiators can also be used as curing agents for epoxy resins or their precursors. As the cationic polymerization initiator, an active energy ray cationic polymerization initiator that generates a cationic species or a Lewis acid by active energy rays or a thermal cationic polymerization initiator that generates a cationic species or a Lewis acid by heat is used. be able to.
For example, phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium tetraphenylborate, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecyl Imidazoles such as imidazole, 1-cyanoethyl-2-methylimidazole, 2,4-dicyano-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine, 1-cyanoethyl- 2-undecylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2-ethyl-4-methylimidazolium tetraphenylborate, 2-ethyl-1,4-dimethylimidazolium tetraphenylborate -Imidazolium salts such as To, 2,4,6-Tris (dimethylaminomethy ) Amines such as phenol and benzyldimethylamine; ammonium salts such as triethylammonium tetraphenylborate; 1,5-diazabicyclo (5,4,0) -7-undecene; 1,5-diazabicyclo (4, And diazabicyclo compounds such as 3,0) -5-nonene.

Further, tetraphenylborate, phenol salt, phenol novolak salt, 2-ethylhexanoate and the like of these diazabicyclo compounds, triflic acid salt, boron trifluoride ether complex compound, metal fluoroboron complex salt, bis (perfluoroalkyl sulfonyl) methane metal salts, aryl diazonium compounds, aromatic onium salts, periodic table dicarbonyl chelate of a IIIa~Va group elements, thiopyrylium salts, MF ₆ ^- anion (where M is phosphorus, antimony Periodic group VIb elements, arylsulfonium complex salts, aromatic iodonium complex salts, aromatic sulfonium complex salts, bis [4- (diphenylsulfonio) phenyl] sulfide-bis-hexafluorometal salts (Eg phosphate, arsenate, antimonate, etc.), ants Or a sulfonium complex salt, an aromatic sulfonium or iodonium salt of a halogen-containing complex ion, or the like. In addition, mixed ligand metal salts of iron compounds and silanol-aluminum complexes can also be used.

  Some of these salts are FX-512 (3M), UVR-6990 and UVR-6974 (Union Carbide), UVE-1014 and UVE-1016 (General Electric) ), KI-85 (Degussa), SP-150 and SP-170 (Asahi Denka), and Sun Aid SI-60L, SI-80L and SI-100L (Sanshin Chemical Co., Ltd.) Available.

  Further, preferred examples of the thermal cationic polymerization initiator include triflate, and examples thereof include diethylammonium triflate, triethylammonium triflate, diisopropylammonium triflate, and ethyl triflate available from 3M as FC-520. Diisopropylammonium and the like (many of which are described in Modern Coatings published October 1980 by RR Alm).

On the other hand, among aromatic onium salts that are also used as active energy ray cationic polymerization initiators, there are those that generate cationic species by heat, and these can also be used as thermal cationic polymerization initiators.
These may be used alone or in combination of two or more.

  Examples of the curing accelerator include amines such as benzyldimethylamine and various imidazole compounds, and phosphines such as triphenylphosphine. These may be used alone or in combination of two or more.

  In addition, the fiber dispersion used in the present invention may contain other inorganic components such as silica and talc for the purpose of lowering the linear thermal expansion coefficient.

[Resin dispersion]
The present invention is characterized in that the surfaces on which the fiber dispersion is formed are bonded to each other on the substrate, and after the fiber dispersion is formed on the first substrate, on the fiber dispersion film, After applying the resin dispersion containing the curable resin and / or the curable resin precursor, the surfaces of the first substrate and the second substrate on which the dispersion is formed are bonded to each other. That is, in the present invention, the resin dispersion functions as a filler and an adhesive that are formed between the fiber dispersion films with low surface smoothness and fills the microscopic voids caused by the roughness and waviness of the fiber dispersion film. Then, the fiber dispersion films containing cellulose fibers are bonded and integrated.

  The resin dispersion contains a curable resin and / or a curable resin precursor as an essential component, and this resin dispersion also has chain transfer as necessary, as in the example described in the fiber dispersion. An agent, an ultraviolet absorber, a filler, a silane coupling agent, a photo / thermal polymerization initiator, a curing agent, a curing accelerator, and further inorganic components such as silica and talc may be contained.

  Moreover, the curable resin and / or curable resin precursor contained in the fiber dispersion and the resin dispersion used for the production of the fiber resin molded body may be the same or different, It is preferable that they are the same.

  A solvent may be contained in the resin dispersion. The content of the curable resin and / or curable resin precursor in the solid content when the solvent is contained in the resin dispersion is usually 80% by weight or more, preferably 85% by weight or more, more preferably Is 90% by weight or more, more preferably 95% by weight or more. When the content of the curable resin and / or curable resin precursor in the resin dispersion is below the lower limit, the amount of the curable resin and / or curable resin precursor as the filler and adhesive component is small. The function as the filler and the adhesive may be deteriorated.

  Moreover, the resin dispersion may contain the same cellulose fiber as contained in the fiber dispersion, and the resin dispersion containing the cellulose fiber is produced in the same manner as the fiber dispersion described above. Is done.

  When the resin dispersion contains cellulose fibers, the content of cellulose fibers in the solid content of the resin dispersion is usually less than 15% by weight, preferably 10% by weight or less, more preferably 8% by weight or less. . Further, it is preferably 0.5% by weight or more, more preferably 1% by weight or more. By including cellulose fibers in the resin dispersion, it is possible to increase the total cellulose fiber content of the obtained fiber resin molded body, and to obtain a fiber resin molded body having further low linear expansion. If the cellulose fiber content is below the lower limit, this effect may not be sufficiently obtained.

  When the resin dispersion contains cellulose fibers, the ratio (weight ratio) between the cellulose fiber content of the fiber dispersion and the cellulose fiber content of the resin dispersion is preferably 0.5: 99.5 to 15:85. The range is more preferably 1:99 to 10:90. Even if the cellulose fiber content in the fiber dispersion is greater than this range and the cellulose fiber content in the resin dispersion is small, or the cellulose fiber content in the fiber dispersion is less than this range, the resin dispersion Even if there is much cellulose fiber content in it, there exists a possibility that the effect of this invention which bonds a fiber dispersion film | membrane using a resin dispersion as a filler and an adhesive agent cannot fully be acquired.

  The amount of solid content in the resin dispersion is not particularly limited, but is preferably 1% by weight or more, more preferably 2% by weight or more, particularly preferably 5% by weight or more, more preferably 100% by weight or less, and more preferably 95% by weight or less. Particularly preferred. If the solid content of the resin dispersion exceeds the above upper limit, the fluidity of the resin dispersion may decrease, making it difficult to apply on the fiber dispersion film. When the amount of the curable resin and / or curable resin precursor is small, the function as a filler and an adhesive may also be deteriorated.

When a solvent is contained in the resin dispersion, examples of the solvent include water and organic solvents described as solvents used in the above-described defibrating treatment.
The content of the solvent in the resin dispersion is preferably 1% by weight or more, more preferably 2% by weight or more, further preferably 5% by weight or more, preferably 99% by weight or less, more preferably 95% by weight or less, Preferably it is 90 weight% or less. If the content of the solvent in the resin dispersion is lower than the above lower limit, the fluidity of the resin dispersion is lowered and it becomes difficult to apply it on the fiber dispersion film, and if it exceeds the upper limit, the solid content is relatively reduced. Thus, the functions as a filler and an adhesive may be impaired.

[substrate]
In the present invention, examples of the first substrate and the second substrate on which the fiber dispersion is formed include a glass substrate, a polyethylene terephthalate substrate, a polyethylene naphthalate substrate, and a polycarbonate substrate. Since the surface properties of the surface are transferred to the surface of the resulting fiber resin molded article, those having excellent surface smoothness are preferred, and the curable resin and / or curing contained in the fiber dispersion or resin dispersion When the curable resin precursor is thermosetting, heat resistance capable of withstanding the heat treatment temperature for thermosetting is required, while the curable resin and / or curable resin precursor is cured by exposure. In this case, a glass substrate is most preferable because it is necessary to have transparency that allows transmission of active energy rays used for exposure.

  Although the thickness of the substrate to be used varies depending on the material, it is preferably about 0.1 to 5 mm in terms of handleability.

[Production method]
Below, with reference to drawings, the manufacturing method of the fiber resin molding of this invention which manufactures a fiber resin molding using the fiber dispersion, the resin dispersion, and the 1st and 2nd board | substrate mentioned above is demonstrated. .

  1 and 2 are schematic cross-sectional views showing an embodiment of a method for producing a fiber resin molded body of the present invention, in which 1A is a first substrate, 1B is a second substrate, and 2A and 2B are fibers. Dispersion film 3 indicates a resin dispersion applied on the fiber dispersion film 2A.

<Film dispersion film formation>
First, a fiber dispersion film is formed on each of the first substrate 1A and the second substrate 1B to obtain fiber dispersion films 2A and 2B.
Here, the respective fiber dispersions formed on the first substrate 1A and the second substrate 1B do not necessarily have to be the same, and the composition and material are within the above ranges. Different fiber dispersions may be used.
However, the fiber dispersion formed on the first substrate 1A and the fiber dispersion formed on the second substrate 1B in terms of material preparation, uniformity of the obtained fiber resin molded body, prevention of warpage, etc. Are preferably the same fiber dispersion.

  Examples of the film forming method include a spin coating method and a dip coating method. Specifically, a known film forming apparatus such as a doctor blade or an applicator may be used. The thickness of film formation can be controlled in consideration of the thickness after solvent drying, but is usually 100 μm or more, preferably 120 μm or more, usually 2000 μm or less, preferably 1500 μm or less. If the film thickness is less than the above lower limit, the thickness after drying the solvent becomes thin, and the number of times of film formation for producing a fiber resin molded body having a desired thickness is not preferable, and if the film thickness exceeds the above upper limit, the solvent is completely volatilized. Otherwise, there is a risk of wrinkles and cracks in the film when the solvent is volatilized.

  At this time, for example, in order to control the film thickness of the resulting fiber resin molded body, two or more layers of the fiber dispersion are laminated on the first substrate 1A and the second substrate 1B as shown in FIG. Also good. In this case, the removal of the solvent by forming the fiber dispersion and drying may be repeated a predetermined number of times. In FIG. 2, three layers of fiber dispersion films 2A and 2B are respectively formed on the first substrate 1A and the second substrate 1B. The number of laminated layers is the same as that of the first substrate 1A and the second substrate 1B. It is not necessarily the same as the substrate 1B, and may be different. Further, the fiber dispersions to be laminated are not necessarily the same, and dispersions having different compositions and materials may be used as long as they are described above. Although there is no restriction | limiting in particular in the upper limit of the lamination number of a fiber dispersion film | membrane, Usually, it is 10 layers or less.

  After forming the fiber dispersion, the solvent contained in the fiber dispersion film is evaporated. The method for evaporating the solvent is not particularly limited, but a method in which high-temperature nitrogen gas is blown in a hot air oven or the like is preferable. The temperature to evaporate is not particularly limited, but it is desirable that the resin is not completely cured. The evaporation temperature is not necessarily higher than the boiling point of the solvent, and the solvent may be gradually evaporated by blowing hot air having a temperature lower than the boiling point.

<Granting resin dispersion>
After forming the fiber dispersion in this way, the film formation surfaces of the first substrate 1A and the second substrate 1B on which the fiber dispersion films 2A and 2B are formed are bonded together, and then the fiber dispersion film The curable resin and / or curable resin precursor in 2A and 2B is cured, but in the present invention, prior to that, the resin dispersion 3 is applied on the fiber dispersion film 2A formed on the first substrate 1A. To do.

  The resin dispersion 3 can also be applied on the fiber dispersion film 2B formed on the second substrate 1B. Usually, the fiber dispersion film 2A and the fibers are applied if applied on one of the fiber dispersion films. Dispersion film 2B can be joined and integrated with good adhesion.

The resin dispersion 3 can be formed into a film in the same manner as the fiber dispersion and applied to the fiber dispersion film 2A in the form of a film, but the resin dispersion 3 is derived from the roughness and undulation of the fiber dispersion film. In general, it is not necessary to form a uniform film on the fiber dispersion film, and it is sufficient that the film is provided in a linear or dotted pattern. Here, if the applied amount of the resin dispersion is too large, the amount of the resin dispersion used in the production of the fiber resin molded body does not include cellulose fibers or the cellulose fiber content is less than the fiber dispersion, The cellulose fiber content of the obtained fiber resin molding may be reduced accordingly, and the effect of low linear expansion may be impaired. However, if the applied amount of the resin dispersion is too small, the fine voids derived from the roughness and undulation of the fiber dispersion film may not be sufficiently filled. Therefore, the amount of resin dispersion applied varies depending on the degree of roughness and swell of the fiber dispersion film depending on the cellulose fiber content of the fiber dispersion used, but the resin per unit surface area of the fiber dispersion film 2A. The solid content of the dispersion 3 is preferably 1 g / m ² or more, more preferably 5 g / m ² or more, and preferably 60 g / m ² or less, and 120 g / m ² or less. Is more preferable.

  In addition, what is necessary is just to provide so that a bubble may not enter, when contacting a film forming surface in a post process, when providing a resin dispersion to a dotted | punctate shape or a linear form. Moreover, when forming a resin dispersion into a film, the same method as the method for forming a fiber dispersion in the previous period can be used.

  After the resin dispersion is applied, the solvent may be removed by drying in the same manner as when the fiber dispersion is formed, and the next curing step may be performed without drying.

<Curing of curable resin and / or curable resin precursor>
After the resin dispersion 3 is applied on the fiber dispersion film 2A as described above, the film formation surfaces of the first substrate 1A and the second substrate 1B are brought into contact with each other, and the fiber dispersion and the resin dispersion The curable resin and / or the curable resin precursor is cured.

  As the curing treatment, for example, a heat treatment and / or an exposure treatment are performed according to the fiber dispersion and the resin in the resin dispersion to remove the solvent. When a resin precursor is used, the precursor is cured through this step to become a resin.

  The heating conditions for performing the curing process by heating are not particularly limited, and when a resin precursor is used, it may be at or above the temperature at which the precursor is cured. Among these, the heating temperature is preferably 60 ° C. or higher, more preferably 100 ° C. or higher, from the viewpoint that the solvent can be volatilized and removed. In addition, from the point which suppresses decomposition | disassembly of a cellulose fiber, 250 degreeC or less is preferable and the heating temperature has more preferable 200 degreeC or less. The heating time is preferably 60 to 180 minutes from the viewpoint of productivity.

  The heat treatment may be performed multiple times by changing the temperature and the heating time. Specifically, primary heating at 60 to 100 ° C. for 30 to 60 minutes, secondary heating at 130 to 160 ° C. for 30 to 60 minutes, and 150 to 200 ° C. which is 40 to 60 ° C. higher than the secondary heating temperature. It is preferable to carry out by three-stage treatment with tertiary heating for ˜60 minutes in that the solvent is completely removed, the surface shape of the resulting fiber resin molded product is reduced, and complete curing is achieved. Note that the heat treatment is preferably performed in at least two stages.

  In the exposure process in the case of performing the curing process by exposure, light such as infrared rays, visible light, and ultraviolet rays, and active energy rays such as radiation such as electron beams are used, preferably light. More preferred is light having a wavelength of about 200 to 450 nm, and even more preferred is ultraviolet light having a wavelength of 300 to 400 nm.

The optimal amount of light irradiation is appropriately selected depending on the resin precursor used, the photopolymerization initiator, etc., but ultraviolet rays having a wavelength of 300 to 450 nm are preferably 0.1 J / cm ² or more, more preferably Is 1 J / cm ² or more, preferably 200 J / cm ² or less, more preferably 30 J / cm ² or less. Moreover, it is more preferable to irradiate by dividing into multiple times. That is, it is preferable to irradiate about 1/20 to 1/3 of the total irradiation amount at the first time and to irradiate the necessary remaining amount after the second time.
It is preferable to use glass substrates as the first and second substrates because such a light transmission is excellent.

  Specific examples of the lamp to be used include a metal halide lamp, a high pressure mercury lamp lamp, an ultraviolet LED lamp and the like.

  After the curing treatment, the first substrate and the second substrate are removed to obtain a fiber resin molded body. The obtained fiber resin molded body may further include 1 to 150-250 ° C. as necessary. Annealing treatment may be performed by heating for about 100 hours.

[Physical properties of fiber resin moldings]
<Cellulose fiber content>
The content of the cellulose fiber in the fiber resin molded body of the present invention is not particularly limited, but is preferably 10% by weight or more, more preferably 15% by weight or more, further preferably 20% by weight or more, and preferably 70% by weight or less, 60% by weight or less is more preferable, and 50% by weight or less is more preferable. When there is too little content of the cellulose fiber in a fiber resin molding, there exists a tendency for effects, such as a linear expansion coefficient reduction, to become inadequate. Conversely, if the content of cellulose fibers in the fiber resin molded body is too large, the resin content is relatively reduced, and the bonding between the fibers by the resin or the filling of the spaces between the fibers becomes insufficient, and the fiber resin There exists a possibility that the intensity | strength of a molded object, transparency, and the flatness of a surface may fall.

  In addition, content of the cellulose fiber and resin in a fiber resin molding can be calculated | required, for example from the weight of the cellulose fiber before hardening, and the weight of the fiber resin molding after hardening. Alternatively, the fiber resin molding can be immersed in a solvent in which the resin is soluble to remove only the resin, and the weight can be determined from the weight of the remaining cellulose fibers. In addition, the functional group of the resin or cellulose fiber can be quantitatively determined using a method of determining from the specific gravity of the resin, NMR or IR.

<Shape and thickness>
The shape of the fiber resin molded body of the present invention is not particularly limited, and may be a plate shape or a plate shape having a curved surface. When the shape is a plate shape (sheet shape, film shape), the thickness (average thickness) is preferably 10 μm or more and 10 cm or less, and by setting such thickness, strength as a structural material can be maintained. it can. The thickness of the fiber resin molded body is more preferably 50 μm to 1 cm, and still more preferably 80 μm to 500 μm.
In addition, in the said plate-shaped object, the film means the plate-shaped object whose thickness is generally 200 micrometers or less, and a sheet | seat means the plate-shaped object thicker than a film.

<Linear expansion coefficient>
The fiber resin molded body of the present invention exhibits a low coefficient of linear expansion (elongation rate per 1K). The linear expansion coefficient of the fiber resin molded body is preferably 1 to 70 ppm / K, more preferably 1 to 60 ppm / K, and particularly preferably 1 to 50 ppm / K.
For example, in a substrate application, since the linear expansion coefficient of an inorganic thin film transistor is about 15 ppm / K, when the linear expansion coefficient of a fiber resin molded body exceeds 50 ppm / K, two layers are combined in an inorganic film. There is a risk that cracks and the like may occur due to a large difference in linear expansion coefficient between layers. Accordingly, the linear expansion coefficient of the fiber resin molded body is particularly preferably 1 to 50 ppm / K.
In addition, a linear expansion coefficient is measured by the method described in the term of the below-mentioned Example.

<Surface roughness>
The fiber resin molding of the present invention is excellent in smoothness on both sides. As the degree of smoothness, as the center line average roughness Ra and the maximum height Rmax measured by the method described in the Examples section below, Ra is 0.5 μm or less on both surfaces, particularly 0. It is preferable that it is 25 μm or less and Rmax is 15 μm or less, particularly 10 μm or less. Ra and Rmax are preferably as small as possible, but as their lower limits, Ra is usually 0.001 μm or more, and Rmax is usually 0.005 μm or more.

  Note that the fiber resin molded body of the present invention usually has substantially the same surface roughness on both surfaces, but when the substrate type is different, the surface roughness of the substrate is transferred to the surface roughness of the fiber resin molded body. Therefore, the surface roughness may be slightly different between the front and back sides.

[Usage]
The fiber resin molded body of the present invention can be used for various applications. Examples of the applications include liquid crystal displays, organic EL displays, optical members and protective films for organic EL lighting, and insulating materials for laminated substrates. Can be mentioned. In particular, because of its excellent low linear expansion and smoothness of both surfaces, it can be suitably used for an insulating material for a liquid crystal display, an organic EL display, an optical member for organic EL lighting, a protective film, or a laminated substrate.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples, and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

[Evaluation of physical properties]
The number average fiber diameter of the cellulose fiber and the evaluation method of the physical properties of the fiber resin molding are as follows.

<Number average fiber diameter of cellulose fibers>
The number average fiber diameter of the cellulose fibers was measured as follows.
The number average fiber diameter is measured. After the solvent is removed from the fine cellulose fiber dispersion by drying, a diagonal line is drawn on a scanning electron microscope (SEM) photograph magnified 20000 times, and fibers in the vicinity thereof are randomly selected. The number average fiber diameter was defined as the average of 10 measured values obtained by spot extraction and removing the thickest fiber and the thinnest fiber.
Apparatus: Scanning electron microscope Carl Zeiss Ultra55
Acceleration voltage: 1.5 kV

<Measurement of surface roughness>
The surface smoothness of the fiber resin molded body is measured using the surface roughness meter (Surfcom E-RM-S18B, manufactured by Tokyo Seimitsu Co., Ltd.) on the front and back surfaces of the fiber resin molded body under the following conditions. And evaluated.
Here, the front surface is the surface side in contact with the first substrate during the production of the fiber resin molded body, and the back surface is the surface side in contact with the second substrate.

<Measurement of linear expansion coefficient>
The fiber resin molded body was cut into 3.0 mm width × 30 mm length. Using a thermomechanical analyzer (TMA “EXSTAR6000” manufactured by SII), the temperature profile is 25 ° C. → (temperature increase of 5 ° C./min) in a tension mode of 20 mm between chucks, a load of 98 mN and a nitrogen gas atmosphere. → 200 ° C. (5 minutes hold) → (5 ° C./minute temperature drop) → −20 ° C. (5 minutes hold) → (5 ° C./minute temperature rise) → 250 ° C. The linear expansion coefficient was determined from the measured values of second run from 60 ° C to 100 ° C.

[Production Example 1: Preparation of cellulose fiber]
Beat hardwood kraft pulp (LBKP) with Niagara Beater (capacity: 23 liters, manufactured by Tozai Seiki Co., Ltd.) for 200 minutes, and add enzymes (cellulase, GC220, manufactured by Genencor) to the pulp for 6 hours of enzyme treatment. What was performed was made into the cellulose fiber raw material.

  The cellulose fiber raw material was dehydrated, and 8 parts by weight of acetic acid and 21 parts by weight of acetic anhydride were added to 1 part by weight (dry weight) of the cellulose fiber and sufficiently stirred. Then, the cellulose was chemically modified (acetyl group introduction) by reacting at 115 ° C. for 5 hours with stirring. After the reaction, the reaction solution was filtered and washed with methanol and demineralized water in this order to obtain a chemically modified cellulose fiber raw material. The modification rate of this cellulose fiber raw material was 27 mol%.

  Water of this cellulose fiber raw material was dehydrated by suction filtration to obtain a cake having a solid content of about 25 to 45% by weight. The step of dispersing and stirring and filtering in isopropyl alcohol 20 times the weight of absolute dry cellulose is performed once, and the step of dispersing and stirring and filtering in 20 times the amount of methyl ethyl ketone is performed twice. Was replaced with methyl ethyl ketone. Next, a solvent was blended so that cellulose fiber raw material / methyl ethyl ketone / cyclohexanone = 1.5 / 23.5 / 75 (weight ratio) to obtain a cellulose fiber raw material dispersion.

This raw material dispersion was subjected to a preliminary dispersion treatment at 13500 rpm for 30 minutes using a high-speed rotating homogenizer (ULTRA TURRAX T25Basic, manufactured by IKA). Next, using a bead mill (Ultra Apex Mill UAM-015, manufactured by Kotobuki Kogyo Co., Ltd.), the cellulose fiber is defibrated by performing 10 passes at a bead diameter of 0.3 mm and a peripheral speed of 11.4 m / sec. A dispersion liquid in which various cellulose fibers were dispersed was obtained. A dispersion obtained by filtering this dispersion with a twilled woven wire mesh having a nominal filtration degree of 28 μm using a pressure filter (KST-90, manufactured by ADVANTEC) was used as a fine cellulose fiber dispersion.
In addition, the number average fiber diameter of the cellulose fiber contained in this fine cellulose fiber dispersion was 38 nm.

[Production Example 2: Preparation of fiber dispersion I]
To the fine cellulose fiber dispersion obtained in Production Example 1, tricyclodecane dimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd. (hereinafter referred to as A-DCP)), photocuring initiator (2, 4 , 6-Trimethylbenzoyldiphenylphosphine oxide, manufactured by BASF, Lucillin TPO (hereinafter referred to as TPO)) was prepared to prepare a fiber dispersion I. The cellulose fiber content in the fiber dispersion I was 1.43% by weight, and the solid content including the cellulose fibers was 7.15% by weight (cellulose fiber content in the solid content: 20% by weight). It was. Moreover, it was cellulose fiber / A-DCP = 20/80 (weight ratio) and A-DCP / TPO = 98/2 (weight ratio).

[Production Example 3: Preparation of Fiber Dispersion II]
The cellulose fiber content is 1.45% by weight, the solid content including the cellulose fiber is 5.79% by weight (cellulose fiber content in the solid content: 25% by weight), and the cellulose fiber / A-DCP = 25 / A fiber dispersion II was prepared in the same manner as in Production Example 2 except that the composition was 75 (weight ratio) and A-DCP / TPO = 98/2 (weight ratio).

[Production Example 4: Preparation of fiber dispersion III]
The cellulose fiber content is 1.45% by weight, the solid content including the cellulose fiber is 4.82% by weight (cellulose fiber content in the solid content: 30% by weight), and the cellulose fiber / A-DCP = 30 / A fiber dispersion III was prepared in the same manner as in Production Example 2 except that 70 (weight ratio) and A-DCP / TPO = 98/2 (weight ratio).

[Production Example 5: Preparation of resin dispersion]
Tricyclodecane dimethanol diacrylate (A-DCP, manufactured by Shin-Nakamura Chemical Co., Ltd.), photocuring initiator (2,4,6-trimethylbenzoyldiphenylphosphine oxide, manufactured by BASF, Lucillin TPO), resin A dispersion (A-DCP / TPO = 100/2 (weight ratio)) was prepared.

[Example 1]
As the first substrate and the second substrate, the fiber dispersion I is respectively applied to a glass substrate having a thickness of 15 cm × 15 cm × 5 mm, and to the first substrate and the second substrate as shown in FIG. Using a blade (manufactured by RK Print Coat Instruments), a film having a thickness of 1000 μm was formed. The solvent was evaporated by blowing hot air nitrogen gas at 80 ° C. for 30 minutes in an oven.
After evaporating the solvent, the applied amount in terms of solid content is 33 g / m ² by dropping the resin dispersion produced in Production Example 5 onto the fiber dispersion film formed on the first substrate. It was dripped like a dot.
This first substrate and the second substrate were bonded together and cured with ultraviolet light. Specifically, a conveyor-carrying UV irradiation device (model QRM-2232-A-00) manufactured by Oak Manufacturing Co., Ltd. equipped with six metal halide lamps with a total output of 80 W / cm, three vertically and 40 cm apart from the workpiece surface. Irradiates light with an integrated light amount of 100 mJ / cm ² from both the upper and lower surfaces at a line speed of 2.8 m / min, and further irradiates light with an integrated light amount of 6400 mJ / cm ² from both the upper and lower surfaces at a line speed of 0.5 m / min. did.
After removing the first substrate and the second substrate, the fiber resin molded body having the cellulose fiber content shown in Table 1 and the thickness shown in Table 1 is further heated at 200 ° C. for 6 hours and annealed. Obtained.
The obtained fiber resin molded product was smooth on both sides by transferring the surface of the glass substrate. The fiber resin molded body was a good molded body without curling.
The evaluation results of this fiber resin molded body are shown in Table 1.

[Example 2]
Except for using the fiber dispersion II instead of the fiber dispersion I, a fiber resin molded body having the thickness shown in Table 1 was obtained in the same manner as in Example 1 but with the cellulose fiber content shown in Table 1.
The obtained fiber resin molded product was smooth on both sides by transferring the surface of the glass substrate. The fiber resin molded body was a good molded body without curling.
The evaluation results of this fiber resin molded body are shown in Table 1.

[Example 3]
Except for using the fiber dispersion III in place of the fiber dispersion I, a fiber resin molded product having the cellulose fiber content shown in Table 1 and the thickness shown in Table 1 was obtained in the same manner as in Example 1.
The obtained fiber resin molded product was smooth on both sides by transferring the surface of the glass substrate. The fiber resin molded body was a good molded body without curling.
The evaluation results of this fiber resin molded body are shown in Table 1.

[Example 4]
In the same manner as in Example 2, after the fiber dispersion II was formed on the first substrate and the second substrate, the solvent was evaporated.
Furthermore, the operation of depositing the fiber dispersion II on the film of the fiber dispersion II on the first substrate and the second substrate thus formed and evaporating the solvent was performed twice. Thus, three layers of the fiber dispersion II were laminated on each substrate. Next, after the resin dispersion was dropped on the fiber dispersion II film in which the three layers were laminated in the same manner as in Example 1, the first substrate and the second substrate were bonded together. In the same manner as in Example 1, after the curing treatment, the first substrate and the second substrate were removed, and then the annealing treatment was performed, and the fibers having the cellulose fiber content shown in Table 1 and the thicknesses shown in Table 1 were obtained. A resin molded body was obtained.
The obtained fiber resin molded product was smooth on both sides by transferring the surface of the glass substrate. The fiber resin molded body was a good molded body without curling.
The evaluation results of this fiber resin molded body are shown in Table 1.
When the cross section in the thickness direction of the fiber resin molded body was observed by SEM, it was confirmed that the upper and lower layers of the fiber dispersion II containing cellulose fibers were integrated with no gap between the layers.

[Comparative Example 1]
In the same manner as in Example 1, after the fiber dispersion I was formed on the first substrate, the solvent was evaporated. A second substrate is placed on the fiber dispersion I film formed on the first substrate, pressed at 80 ° C. and 0.2 MPa for 10 minutes, and then cured in the same manner as in Example 1. went.
Thereafter, the first substrate and the second substrate were removed, and an annealing treatment was performed in the same manner as in Example 1 to obtain a fiber resin molded body.
In this fiber resin molded body, the second substrate and the fiber dispersion film did not adhere to each other, and this surface was not a smooth surface.

[Comparative Example 2]
In the same manner as in Example 1, after the fiber dispersion I was formed on the first substrate 1A, the solvent was evaporated. After the solvent was evaporated, the resin dispersion was dropped on the fiber dispersion I film formed on the first substrate in the same manner as in Example 1. This was covered with a second substrate 1B, and a fiber resin molded body was obtained by performing a curing treatment and an annealing treatment in the same manner as in Example 1.
The obtained fiber resin molded product was smooth on both sides by transferring the surface of the glass substrate. However, it has a two-layer structure of a layer containing cellulose fibers and a layer not containing cellulose fibers, and the difference in linear expansion coefficient between the two is large, so curling has occurred.

DESCRIPTION OF SYMBOLS 1A 1st board | substrate 1B 2nd board | substrate 2A, 2B Fiber dispersion film | membrane 3 Resin dispersion

Claims (4)

A method for producing a fiber resin molded product in which cellulose fibers are dispersed in a resin,
A fiber dispersion containing cellulose fibers and a curable resin and / or a curable resin precursor on the first substrate and the second substrate, respectively, and the cellulose fiber content in the solid content of the fiber dispersion A fiber dispersion having a weight of 15% by weight or more,
On the fiber dispersion film formed on the first substrate, after further applying a resin dispersion containing a curable resin and / or a curable resin precursor,
Bonding the surfaces of the first substrate and the second substrate on which the fiber dispersion is formed,
Then, characterized that you integrated by curing the curable resin and / or curable resin precursor fiber dispersion on the substrate of the first and the resin dispersion and the fiber dispersion of the second substrate The manufacturing method of a fiber resin molding.   The method for producing a fiber resin molded body according to claim 1, wherein two or more layers of the fiber dispersion are laminated on the first substrate and the second substrate, respectively.   The said resin dispersion contains less than 15 weight% cellulose fiber in solid content of this resin dispersion, The manufacturing method of the fiber resin molding of Claim 1 or 2 characterized by the above-mentioned.   The number average fiber diameter of the said cellulose fiber is 400 nm or less, The manufacturing method of the fiber resin molding as described in any one of Claims 1-3 characterized by the above-mentioned.

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