JP2010024376A - Cellulose fiber composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cellulose fiber composite material satisfactorily securing high strength, a high elastic modulus and a low linear expansion property by multiplexing the cellulose fiber and having low phase difference, a low haze value and high light transmittance and excellent optical characteristics such as optical isotropy and transparency. <P>SOLUTION: The cellulose fiber composite material including the cellulose fiber and a matrix material has ≥40 wt.% cellulose fiber content, ≤20 nm phase difference in 50 μm thickness and ≤5% haze value by JIS K7136 in one thickness of 10 to 200 film thickness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite material composed of cellulose fibers and a matrix material, and more specifically, a cellulose fiber composite material that realizes a low phase difference, a low haze, and a high light transmittance by a cellulose fiber film having a low orientation and a high content. About.

  In general, glass plates are widely used for display substrates such as liquid crystal and organic EL. However, since the glass plate has high specific gravity and is difficult to reduce in weight, and has drawbacks such as being easily broken, not being bent, and having a large thickness, application of a plastic substrate in place of the glass plate has been studied in recent years. Specifically, a display substrate using polycarbonate, polyethylene terephthalate, or the like is used.

However, these conventional plastic materials for glass replacement have a larger coefficient of linear expansion than glass plates, so during the process of vapor-depositing device layers such as thin film transistors on the substrate at high temperatures, warping, cracking of the deposited film, semiconductor Problems such as disconnection are likely to occur and practical use is difficult.
For this reason, a plastic material having high transparency, high heat resistance, low water absorption, and a low linear expansion coefficient is required as a material applied to these applications.

  In recent years, composite materials using fine cellulose fibers such as bacterial cellulose have been studied extensively. Since cellulose has an extended chain crystal, it is known to exhibit a low linear expansion coefficient, a high elastic modulus, and a high strength. In addition, micronized and highly crystalline cellulose nanofibers with a thickness in the range of several nm to 200 nm are obtained by miniaturization, and high transparency and low linear expansion coefficient are obtained by filling the gaps between the fibers with a matrix material. It is reported that a composite material can be obtained.

  However, in the past, there has been little report on optical isotropy important for display substrates such as liquid crystal and organic EL in composite materials using fine cellulose fibers.

  For example, Patent Document 1 describes a composite material of bacterial cellulose and a photo-curable resin. Water in bacterial cellulose is completely replaced with isopropanol, and after cold pressing, impregnated with an ultraviolet curable resin and irradiated with ultraviolet rays. However, in this method, anisotropy tends to occur in the direction of the fiber, such as orientation along the water stream from which bacterial cellulose flows during cold pressing. Therefore, there is a problem that the obtained composite material has a large phase difference. According to the study by the present inventors, bacterial cellulose is generally in the form of a flat ribbon having a cross section of 10 nm × 50 nm, and the fiber diameter is large, so that a light scattering phenomenon occurs. For this reason, this composite material also has a problem that haze is large.

  Moreover, in patent document 1, patent document 2, patent document 3, and patent document 4, nanofiber cellulose fiber (hereinafter abbreviated as “NFFCe”) obtained by grinding using wood as a raw material and a photocurable resin There is a description about the composite material, and according to the study by the present inventors, the average fiber diameter of this NFCe is estimated to be about 60 nm. With this composite material, the phase difference is smaller than when bacterial cellulose is used. Conceivable. However, even if the phase difference is small, cellulose fibers having a large fiber diameter remain, which causes a problem of light scattering and a large haze.

In Patent Document 5, there is a description regarding a material in which bacterial cellulose is pre-dispersed with a mixer and dispersed at 80 MPa with a high-pressure homogenizer to form a composite material with a thermosetting resin. However, the fiber diameter of bacterial cellulose is as thick as 50 to 60 nm. Therefore, there is a problem that the light transmittance is lowered. In addition, since the fiber diameter of bacterial cellulose is large, there is a problem that scattering is large and optical properties are inferior, and haze is increased (transparency is deteriorated). Of course, in the example of Patent Document 5, since the cellulose fiber content is small, even if the phase difference is within an allowable range, the phase difference per contained fiber becomes large, and the balance between optical properties and mechanical properties. Is thought to be worse.
Furthermore, as long as bacterial cellulose is used, it takes time to culture, and there is a problem that it is difficult to supply in large quantities.

In Patent Document 6, a nonwoven fabric is obtained using cotton linter as a raw material. However, according to the study by the present inventors, it was found that when cotton linter was used, defibration with about 10 passes of high-pressure homogenizer treatment was insufficient, and the haze when combined with the matrix material was large. This is presumably because cotton linters have high crystallinity and cannot be sufficiently defibrated unless a large shear stress is applied.
JP 2006-241450 A JP 2006-35647 A JP 2006-240295 A JP 2008-24778 A JP 2006-316253 A WO2006 / 004012 Publication

  As described above, although cellulose fibers have excellent properties such as high strength and low linear expansion coefficient, the conventional composite material exhibits the anisotropy of the cellulose fiber membrane derived from the high aspect ratio of the cellulose fibers. As a result, when a composite material is used, the phase difference (optical anisotropy) becomes large, and light scattering caused by mixing of large-diameter cellulose fibers causes various display substrate materials and solar cells. There has been a problem that sufficient performance for use as various display substrate materials cannot be obtained as a use for a display substrate, a window material and the like.

  The present invention solves this problem, sufficiently secures high strength, high elastic modulus and low linear expansion due to the composite of cellulose fibers, and has low phase difference, low haze, high light transmittance, optical properties, etc. An object is to provide a cellulose fiber composite material excellent in optical properties such as isotropic and transparency.

As a result of intensive studies to solve the above-mentioned problems, the present inventors adopted a specific defibrating method, and diluted and filtered the obtained cellulose fiber dispersion to include large-diameter fibers. In addition, by uniformly dispersing fine cellulose fibers with a uniform fiber diameter in a low orientation, a cellulose fiber membrane with a low orientation can be obtained, and by combining a matrix material with this cellulose fiber membrane, a high It has been found that a composite material having transparency, low retardation and low haze can be obtained.
The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] A cellulose fiber composite material including cellulose fibers and a matrix material, wherein the cellulose fiber content is 40% by weight or more, the phase difference at a thickness of 50 μm is 20 nm or less, and the film thickness is 10 μm or more and 200 μm or less. A cellulose fiber composite material having a haze of 5% or less according to JIS K7136.

[2] The cellulose fiber composite material according to [1], wherein the refractive index of the matrix material with respect to light having a wavelength of 587.6 nm is 1.45 to 1.65 at 25 ° C.

[3] A cellulose fiber membrane produced by filtering a cellulose fiber dispersion having a cellulose fiber content of 0.01 to 0.2% by weight is combined with a matrix material [1] or The cellulose fiber composite material according to [2].

[4] Any one of [1] to [3], wherein the cellulose fiber raw material liquid is defibrated (miniaturized) by ejecting from a high-pressure atmosphere of 100 MPa or more and decompressing, and then filtered. The cellulose fiber composite material described.

[5] The cellulose fiber composite material according to any one of [1] to [4], wherein the total light transmittance according to JIS K7105 is 87% or more when the film thickness is 10 μm or more and 200 μm or less.

[6] The light transmittance in the entire wavelength range of 400 to 800 nm is 85% or more, and the slope of the light transmittance in the wavelength range of 400 nm to 600 nm is 0.022 (% / nm) or less. [1] The cellulose fiber composite material according to any one of [5].

  According to the present invention, a cellulose fiber composite material having a high strength, a high elastic modulus, and a low linear expansion coefficient, in which a matrix material is combined with a cellulose fiber, is excellent in transparency, and has a low retardation (optical isotropy). An excellent cellulose fiber composite material having excellent optical performance with low haze is provided.

  The cellulose fiber composite material of the present invention has a low linear expansion coefficient, a high elastic modulus, a high strength and a high transparency, a low phase difference, and a low haze required by combining cellulose fibers with a resin, for example, It is useful for various display substrate materials, solar cell substrates, window materials and the like.

  Embodiments of the present invention will be specifically described below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

The cellulose fiber composite material of the present invention is a cellulose fiber composite material containing cellulose fibers and a matrix material, and satisfies the following (1).
(1) The cellulose fiber content is 40% by weight or more, the phase difference at a thickness of 50 μm is 20 nm or less at any film thickness of 10 μm or more and 200 μm or less, and the haze according to JIS K7136 is 5% or less.

  Such a cellulose fiber composite material of the present invention has a cellulose fiber content of, for example, 0.1% after defibration (miniaturization) by ejecting a cellulose fiber raw material liquid from a high-pressure atmosphere of 100 MPa or more and reducing the pressure. A cellulose fiber dispersion of 01 to 0.2% by weight is obtained, and the cellulose fiber membrane produced by filtering this dispersion is combined with a matrix material.

[1] Manufacture of Cellulose Fiber Membrane First, the cellulose fiber composite material of the present invention will be described according to the procedure for manufacturing the cellulose fiber membrane, which is preferably used for the manufacture of the cellulose fiber composite material of the present invention. Is an example of a method for producing a cellulose fiber membrane constituting the cellulose fiber composite material of the present invention, and the method for producing the cellulose fiber membrane used in the cellulose fiber composite material of the present invention is limited to the following production methods. In addition, the cellulose fiber composite material of the present invention is not necessarily limited to one using a cellulose fiber membrane produced by the following method.

  The cellulose fiber membrane according to the present invention (hereinafter sometimes referred to as “cellulose fiber membrane of the present invention”) is preferably a cellulose raw material liquid obtained by purifying a wood material in water at a high pressure atmosphere of 100 MPa or more. A filter medium is obtained by diluting a cellulose fiber dispersion obtained by defibration (miniaturization) by a specific method such as jetting from below and reducing the pressure to 0.01 to 0.2% by weight and filtering. On top of this, a wet film of cellulose fiber in which a large amount of dispersion medium remains is formed, and this wet film is manufactured by hot press molding.

[Preparation of cellulose fiber raw material liquid]
<Cellulose fiber raw material>
The cellulose fiber used in the present invention is preferably made of a woody material, that is, a conifer or a hardwood.
Other examples of the raw material for cellulose fibers include bacterial cellulose produced by bacteria, cotton such as cotton linter and cotton lint, seaweed such as valonia and rhododendron, and scallops. Among these, the method for obtaining cellulose from a woody material is advantageous in that it can be obtained easily and efficiently compared to other raw materials since it has been industrialized for a long time as the paper industry. Moreover, woody materials are the largest amount of biological resources on the planet, and since they are sustainable resources that are produced in an amount of more than 70 billion tons per year, they contribute to the reduction of carbon dioxide that affects global warming. It is also large and has an environmental and economic advantage.

<Purification treatment>
The above-mentioned wood material is preferably purified in an aqueous medium to remove substances other than cellulose in the wood material, such as lignin, hemicellulose, resin (resin) and the like.

As an aqueous medium used for the purification treatment of the woody material, water is generally used. However, an aqueous solution of an acid or base or other treatment agent is preferably used, and can finally be washed with water. is there.
In addition, temperature and pressure may be applied during the refining process, and this raw wood material may be crushed into a state such as wood chips or wood flour. The crushing may be performed before, during or after the refining process. You can go at the timing. Moreover, you may perform the below-mentioned chemical modification to the refined cellulose.

  In addition, if the cellulose is kept wet without being completely dried after the purification process is completed during the purification process, the cellulose fiber dispersion liquid can be efficiently used at the time of subsequent fibrillation (miniaturization) of the cellulose fiber. Since it can be obtained, it is preferable not to completely dry the cellulose during and after the purification treatment.

<Fracture of wood material>
When crushing wood material before, during, or after refining, for example, before refining, use an impact pulverizer or shear pulverizer, and during refining and after refining. If there is a refiner or the like, it is preferably pulverized to a particle size of 500 μm or less, more preferably a particle size of 300 μm or less, still more preferably a particle size of 250 μm or less. The lower limit of the particle size is not particularly limited, but in reality, the particle size is 1 μm or more.
Practically, it is preferable to use wood flour that has been crushed and classified to an average particle size of about 50 to 250 μm as a raw material.

<Treatment agent>
The acid or base used for the purification treatment of the woody material and other treatment agents are not particularly limited, but for example, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, sodium sulfide , Magnesium sulfide, sodium hydrosulfide, sodium sulfite, calcium sulfite, magnesium sulfite, ammonium sulfite, sodium sulfate, sodium thiosulfate, sodium oxide, magnesium oxide, calcium oxide, acetic acid, oxalic acid, sodium hypochlorite, hypochlorite Calcium oxide, sodium chlorite, sodium chlorate, chlorine dioxide, chlorine, sodium perchlorate, sodium thiosulfate, hydrogen peroxide, ozone, hydrosulfite, anthraquinone, dihydrodihydroxyanthracene, tetrahydroa Torakinon, anthrahydroquinone, also ethanol, methanol, and water-soluble organic solvents such as alcohols and acetone and 2-propanol. These treatment agents may be used alone or in combination of two or more.
In addition, two or more purification agents can be used for two or more purification treatments. In that case, washing treatment with water may be performed between purification treatments using different treatment agents.

<Temperature, pressure>
There are no particular restrictions on the temperature and pressure during the purification treatment, and the temperature is 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. or less. It is preferable.

<Water content>
It is preferable that the cellulose is always in a wet state without being completely dried after the purification process and after the purification process. As the degree of water content, cellulose (including impurities and the like described later), water and It is preferable that the amount of water is 50% by weight or more, particularly 60% by weight or more, particularly 70% by weight or more, and most desirably 80% by weight or more based on the total weight.
Hereinafter, this ratio is simply referred to as “water content of cellulose”. This water content is calculated | required by the method based on JISP8203. Specifically, after measuring the weight of the cellulose sample before drying, it was dried in a dryer at 105 ° C. for 3 hours, allowed to cool in a desiccator containing a desiccant such as blue silica gel for 45 minutes, and then dried. Measure. The water content can be determined from the mass before and after drying.

<Degree of purification>
The cellulose obtained by the purification treatment of the wood material is preferably one in which substances other than cellulose in the wood material are sufficiently removed, and the impurity content after the purification treatment is 20% by weight or less, particularly 10% by weight or less. In particular, 5% by weight or less is preferable.
In addition, impurity content after a refinement | purification process can be investigated by well-known methods, such as a gravimetric method, IR, UV, NMR, a liquid chromatography, and TG-DTA.

[Specific defibration method]
Any specific defibrating method may be used as long as the fiber diameter is reduced.
For example, there is a fibrillation method by purifying a woody material as described above and, if necessary, crushing and classifying the cellulose fiber raw material liquid obtained by jetting from a high-pressure atmosphere and reducing the pressure. In addition, when the cellulose fiber raw material liquid is passed through the gap between the blade that rotates at high speed and the slit that rotates fixedly or in reverse, a rotational defibrating method that defibrates by applying shear stress, or an ultrasonic generator Examples include a method in which the cellulose fiber raw material liquid is brought into contact with the vibration surface to defibrate by a shearing force generated when the generated cavitation disappears.

[Defibration (miniaturization) treatment by ejection]
First, a method for refining (miniaturizing) a cellulose fiber raw material liquid obtained by purifying a woody material as described above, and pulverizing and classifying the material as necessary, and blowing it out from a high-pressure atmosphere to reduce the pressure. Is described in detail.

<Concentration of cellulose fiber raw material liquid>
The cellulose fiber raw material liquid is a suspension of an aqueous medium of cellulose obtained by treating a wood material, preferably an aqueous suspension. The cellulose concentration (solid content concentration) is 0.2% by weight or more and 1 It is preferably 0.0% by weight or less, particularly 0.3% by weight or more and 0.8% by weight or less, and particularly preferably 0.4% by weight or more and 0.6% by weight or less.
If the cellulose concentration in the cellulose fiber raw material liquid is too low, the amount of the cellulose fiber raw material liquid will increase too much relative to the amount of cellulose to be processed, and the efficiency will be poor. If the cellulose concentration is too high, it may be difficult to eject from the pores. .
Therefore, when the cellulose concentration of the cellulose fiber raw material liquid obtained by the treatment such as refining is not within this concentration range, it is preferable to adjust to the above concentration range by appropriately adding water.

<Ejection conditions>
In the present invention, the cellulose fiber raw material liquid is defibrated (miniaturized) by ejecting it from a high-pressure atmosphere of 100 MPa or more and reducing the pressure. As the jetting means, it is preferable to use an ultra-high pressure homogenizer. Specifically, the cellulose fiber raw material liquid is pressurized to 100 MPa or more, preferably 150 MPa or more, more preferably 200 MPa or more, further preferably 220 MPa or more with a pressure intensifier, It is ejected from a nozzle having a pore diameter of 50 μm or more, and the pressure is reduced so that the pressure difference is 50 MPa or more, preferably 80 MPa or more, more preferably 90 MPa or more. The cellulose fibers are defibrated (miniaturized) 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 reduced pressure condition is small, the defibration (miniaturization) efficiency is lowered and the number of repeated ejections for obtaining the desired fine cellulose fiber is large. This is not preferable because it is necessary. In addition, even when the pore diameter of the pores from which the cellulose fiber raw material liquid is ejected is too large, a sufficient defibration (miniaturization) effect cannot be obtained. There is also a possibility that the fine cellulose fiber of this may not be obtained.

  The ejection of the cellulose fiber raw material liquid can be repeated a plurality of times as necessary, thereby increasing the degree of refinement and obtaining desired fine cellulose fibers. The number of repetitions (pass number) is usually 1 time or more, preferably 3 times or more, more preferably 5 times or more, still more preferably 10 times or more, and usually 100 times or less, preferably 50 times or less, more preferably 20 times. No more than 15 times, more preferably no more than 15 times. 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.

The ultra-high pressure homogenizer is not particularly limited, but “Ultimator” manufactured by Suginoma Machine Co., Ltd. can be used as a specific apparatus.
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. .

  Moreover, if the diameter of the pores through which the cellulose fiber raw material liquid 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 50 μm or more and 800 μm or less, preferably 100 μm or more and 500 μm or less, more preferably 150 μm or more and 350 μm or less.

  Although there is no restriction | limiting in particular in the temperature at the time of ejection (cellulose fiber raw material liquid temperature), Usually, they are 5 degreeC or more and 100 degrees C or less. 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.

  The number of the ejection nozzles may be one or two, and the ejected cellulose may hit a wall, ball, or ring provided at the ejection destination. Furthermore, when there are two nozzles, celluloses may collide with each other at the ejection destination.

[Fabrication (miniaturization) by rotary defibration method]
Next, the rotational defibrating method will be described.
In this case, the concentration of the cellulose fiber raw material liquid is preferably 0.2% by weight or more and 1.0% by weight or less as described above.
Examples of the rotary defibrating apparatus include ULTRA-TURRAX T-25 and T50, T65D manufactured by IKA, CLEAMIX manufactured by COMTECHNIK, POLYTRON, and MEGATRON manufactured by KINEMATICA.

  Taking Claremix as an example, this device is composed of a rotating blade called a rotor and a fixed blade having a slit called a screen facing a narrow gap, and the rotor rotates at a high speed of tens of thousands of rpm. The cellulose fiber raw material liquid to which kinetic energy is applied is subjected to a large shearing force when passing through the screen slit at a high speed, and is defibrated so as to avoid from between the fibers. The larger the number of revolutions, the greater the shearing force that is generated, which is preferably 10,000 rpm or more, and more preferably 20,000 rpm or more. If the screen rotates in the opposite direction to the rotor, the shearing force becomes even larger, which is very preferable. The treatment time is preferably 10 seconds to 1 hour, more preferably 1 minute to 30 minutes. If the treatment time is shorter than 10 seconds, defibration is insufficient, and even if it exceeds 1 hour, further improvement in the degree of defibration cannot be expected, which is not efficient.

<Defibration (miniaturization) treatment by ultrasonic treatment>
Next, defibration (miniaturization) by ultrasonic treatment will be described.

  The cellulose fiber raw material liquid or the cellulose fiber raw material liquid that has been refined (defibrated) is subjected to ultrasonic treatment to be defibrated (fine sized).

  Although there is no limitation in particular as an ultrasonic processing apparatus, Ultrasonic homogenizer UH600S made from SMT, UIP1000 made from Healscher, Sonifier S-450D made from Nippon Emerson Co., Ltd., etc. can be used as a specific apparatus.

  The longer the ultrasonic irradiation time is, the longer the fiber is defibrated, but it is usually 10 minutes or longer, preferably 30 minutes or longer, more preferably 60 minutes or longer. Moreover, the irradiation time of 4 hours or less is preferable. Long-term treatment exceeding 4 hours is not preferable because the fiber crystals are broken and gelled.

If the ultrasonic wave is continuously processed, the temperature continues to rise, so intermittent operation of about 50% may be performed.
In the ultrasonic treatment, since the ultrasonic wave is generated by resonating the piezoelectric element, the output depends on the size of the piezoelectric element. When the frequency is low, the output can be high, and when the frequency is high, the output is low. The frequency is preferably 20 kHz or more and 1000 kHz or less. If the frequency is less than 20 kHz, the effect of ultrasonic treatment cannot be expected. When the frequency exceeds 1000 kHz, radicals are generated and the cellulose fibers are damaged. The output is preferably 300 W or more, more preferably 600 W or more, and even more preferably 1200 W or more.

  The processing chip is not particularly limited, but a titanium alloy may be used.

  In addition, the above-mentioned defibrating process may be used independently or may be used in combination. In particular, the defibration by ultrasonic treatment is preferably performed after passing through an ejection type defibration method from a high pressure or a rotary type defibration method.

<Treatment with a centrifuge>
Dispersion that has been sufficiently defibrated by a centrifuge from the defibrated (miniaturized) cellulose fiber dispersion, and a treatment that has been subjected to ultrasonic treatment and dispersion that has been insufficiently defibrated. It can be separated from the fine particles of the chip. A sufficiently defibrated dispersion becomes a supernatant by a centrifuge process.

  Although there is no limitation in particular as a centrifuge, Hitachi Koki centrifuge CR-22G can be used as a specific apparatus.

  As for the operating conditions of the centrifuge, the number of rotations is preferably 5000 rpm or more, more preferably 10,000 rpm or more, and further preferably 15,000 rpm or more. The operating time is preferably 5 minutes or longer, more preferably 10 minutes or longer, and even more preferably 30 minutes or longer.

<Fiber diameter and fiber length of cellulose fiber>
The fiber diameter of the cellulose fiber obtained by the above-described defibration (miniaturization) treatment is small, and when it is combined with a matrix material such as a resin, it is preferable in that a highly transparent one can be obtained.

  Although the fiber diameter of a cellulose fiber can be confirmed by SEM observation, it is preferable that the fiber diameter of the cellulose fiber obtained by the above-mentioned method is 4-200 nm by the average value of the fiber diameter observed from SEM. If the average fiber diameter of the cellulose fibers exceeds 200 nm, it is not preferable because it approaches the wavelength of visible light and refraction of visible light tends to occur at the interface with the matrix material, resulting in a decrease in transparency. Moreover, a fiber having a fiber diameter of 4 nm or less cannot be substantially produced. From the viewpoint of transparency of the resulting composite material, the average fiber diameter of the cellulose fibers is more preferably 4 to 100 nm.

  Moreover, although it does not specifically limit about the length of a cellulose fiber, 100 nm or more is preferable on average. If the average length of the cellulose fibers is shorter than 100 nm, the strength of the resulting composite material may be insufficient.

[Filtration of cellulose fiber dispersion]
A cellulose fiber membrane is produced by filtering the cellulose fiber dispersion obtained by the above-described defibration (miniaturization) treatment by jetting. In the present invention, when the cellulose fiber dispersion is filtered, the cellulose fiber dispersion obtained by the above-mentioned defibration (miniaturization) treatment is preferably made to have a cellulose fiber content of 0.01 to 0.2% by weight. Then, the solution is diluted and filtered (hereinafter, the diluted dispersion may be referred to as “cellulose fiber diluted solution”).

<Cellulose fiber diluent>
The cellulose fiber concentration of the diluted solution of cellulose fibers according to the present invention is 0.01 to 0.2% by weight, preferably 0.02 to 0.15% by weight. By using a cellulose fiber dispersion liquid having such a concentration, the cellulose fiber film can be obtained by filtration so as to obtain a cellulose fiber film having no anisotropy by filtration.
If this dilution is not performed, the cellulose fiber dispersion will be filtered in a liquid crystal phase, and the cellulose fibers will be oriented by the flow of the filtrate generated during filtration, resulting in an anisotropic cellulose fiber membrane. It has a strong (phase difference) and becomes a problem in display applications.

That is, the cellulose fiber dispersion exhibits a liquid crystal phase (nematic phase) at a concentration of about 0.2% by weight or more. Further, when the concentration is about 1% by weight, the viscosity of the dispersion increases, and a higher order phase is formed. When the cellulose fiber dispersion is filtered and formed at a concentration higher than the concentration indicating the liquid crystal phase, the cellulose fibers have anisotropy, so that a plurality of domains oriented in one direction are formed, or the product is heated and dried from any concentration. Film formation is undesirable because it has a multi-domain structure and thus the phase difference increases.
When the cellulose fiber dispersion is being filtered, a flow is generated in a direction substantially passing through the filtration surface. However, as the filtration proceeds, cellulose fibers are deposited and a cake layer is formed in which the filtrate is difficult to pass through. Therefore, a filtrate flow is generated toward a portion having a low filtration resistance. In this case, when the cellulose fiber dispersion is in a liquid crystal phase, anisotropy is exhibited in the cellulose fiber film by flow orientation. On the other hand, when the cellulose fiber dispersion is diluted to form an isotropic phase, the cellulose fibers are individually deposited, so that the cellulose fiber membrane obtained by filtration is almost isotropic without anisotropy.

  In the dilution of the cellulose fiber dispersion, the cellulose fiber dispersion may be diluted while being dispersed with an ultrasonic disperser of about 20 kHz to 100 kHz and 100 W to 1000 W. For dilution of the cellulose fiber dispersion, a dilution medium similar to the dispersion medium in the cellulose fiber dispersion, preferably water, is used.

  Whether the liquid crystal phase of the cellulose fiber dispersion is isotropic can be determined using two linear polarizing plates. Usually, even when two linearly polarizing plates are vertically stacked and the transmitted light is observed, the light does not pass through and only appears black. Similarly, when an isotropic liquid is placed between two polarizing plates under transmitted light and observed in a container having no anisotropy, it does not transmit light and only appears black. On the other hand, if a liquid crystal phase liquid is placed between two polarizing plates under transmitted light and observed in a container having no anisotropy, light is partially transmitted and a light pattern (texture) can be observed. . As the transmitted light used for this observation, Hakuba Photo Industry Co., Ltd. Light Viewer 5700 may be used.

<Filter media>
Filtration media such as filtration filters and filter cloths used for filtration of cellulose fiber dispersions, preferably cellulose fiber diluents, have an air permeability of 1 to 20 cm ³ · when a differential pressure of 124.5 Pa is applied. cm ^-2 · ^{min -1,} in particular ^{2~15cm 3 · cm -2 · min -1} , is preferably especially ^{3~10cm 3 · cm -2 · min -1} . When the air permeability of the filter medium is larger than 20 cm ³ · cm ⁻² · min ⁻¹ , there arises a problem that the cellulose fibers in the cellulose fiber dispersion (preferably cellulose fiber dilution) are almost lost. Moreover, when the air permeability of the filter medium is smaller than 1 cm ³ · cm ⁻² · min ⁻¹ , there arises a problem that the filtration time of the cellulose fiber dispersion (preferably cellulose fiber diluted solution) takes too long.

  When filtering a cellulose fiber dispersion, preferably a diluted cellulose fiber solution, it is important to perform the filtration in a horizontal state on the surface of the filter medium that is as smooth as possible. When filtration is performed on the uneven filter medium surface, the resulting cellulose fiber membrane becomes uneven, which is an obstacle in creating a smooth composite material as well as an optical viewpoint. Further, if filtration is performed in a non-horizontal state, a difference in film thickness is generated in the resulting cellulose fiber membrane, which is not desirable for producing a uniform composite material.

  In addition, when performing filtration, you may perform suction filtration in order to remove the solvent of a cellulose fiber dispersion liquid. In this case, the vacuum degree of suction is preferably about −90 to −100 kPa. If the degree of decompression is too large, it becomes very large due to the pressure resistance of the apparatus, which is not practical. On the other hand, if it is too small, the advantage of performing suction cannot be obtained sufficiently. Moreover, you may perform pressure filtration. The degree of pressurization is preferably about 100 to 400 kPa.

  In the present invention, in the film forming process by filtration, the water in the wet film formed on the filter medium may be finally replaced with an organic solvent such as alcohol. As described later, a cellulose fiber membrane having a relatively high porosity can be obtained. In this solvent replacement, water is removed by filtration, and an organic solvent such as alcohol is added when the cellulose fiber content of the wet membrane on the filter medium reaches 5 to 99% by weight. Alternatively, after the cellulose fiber dispersion (cellulose fiber diluted solution) is put into the filtration device, the organic solvent such as alcohol is added at the end of the filtration by gently pouring it on top of the dispersion containing the organic solvent such as alcohol. Can be replaced.

  The organic solvent such as alcohol used here is not particularly limited. For example, in addition to alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol, acetone, methyl ethyl ketone, tetrahydrofuran, cyclohexane 1 type, or 2 or more types of organic solvents, such as toluene and carbon tetrachloride. When using a water-insoluble organic solvent, it is preferable to use a water-soluble organic solvent or a mixed solvent with the water-soluble organic solvent, and then replace with a water-insoluble organic solvent.

<Heating press>
Water and / or organic solvent is removed by heat-pressing a wet membrane made of cellulose fiber containing water and / or an organic solvent in which water is solvent-substituted, formed on the filter medium by filtration as described above. Thus, the cellulose fiber membrane of the present invention can be obtained. In addition, water and / or organic solvent content of the wet film | membrane used for this heat press are 65 to 95 weight% normally, Preferably it is 70 to 90 weight%, More preferably, it is 75 to 85 weight%. If the water and / or organic solvent content of the wet film used for the heating press is too large, the shape of the wet film may be crushed during the pressure press, and if it is too small, it becomes difficult to form pores. There is a possibility that the matrix material is difficult to enter between the cellulose fibers at the time of preparation.

The heating temperature during the hot pressing of the wet film is usually 70 to 170 ° C, preferably 90 to 150 ° C, and more preferably 110 to 130 ° C.
If this heating temperature is too low, drying may take time or drying may be insufficient, and if the heating temperature is too high, the cellulose fiber membrane may be colored or decomposed.

  Moreover, as pressurization conditions of a hot press, it is 0.02-2 MPa normally, Preferably it is 0.05-1 MPa, More preferably, it is 0.1-0.5 MPa. If this pressure is too low, drying may be insufficient, and if the pressure is too high, the cellulose fiber membrane may be crushed or decomposed.

  The heating press time varies depending on the conditions of the heating press, but is usually about 2 to 10 minutes.

  In addition, when performing the chemical modification of the below-mentioned nonwoven fabric, after performing this heat press, you may perform a chemical modification and may dry finally.

[Chemical modification]
The cellulose fiber used in the present invention may be a chemically modified cellulose fiber. The chemical modification means that the hydroxyl group in cellulose is chemically modified by reacting with a chemical modifier.
The chemical modification may be performed after the cellulose fiber is converted into a cellulose fiber film, or after the chemical modification, the cellulose fiber film may be formed. Preferably, chemical modification is performed after forming the cellulose fiber membrane.

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

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

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

  Examples of the acid include acetic acid, acrylic acid, methacrylic acid, propanoic acid, butanoic acid, 2-butanoic acid, and pentanoic acid.

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

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

<Chemical modification rate>
The term “chemical modification rate” as used herein refers to the proportion of all hydroxyl groups in the cellulose fiber that have been chemically modified, and the chemical modification rate can be measured by the following titration method.

これを解いていくと、以下の通りである。

<Measuring method>
A cellulose fiber membrane 0.5 g is precisely weighed, and 6 mL of methanol and 2 mL of distilled water are added thereto. After stirring this at 60-70 ° C. for 30 minutes, 10 mL of 0.05N aqueous sodium hydroxide solution is added. The mixture is stirred at 60 to 70 ° C. for 15 minutes and further stirred at room temperature for one day. Titrate with 0.02N aqueous hydrochloric acid using phenolphthalein.
Here, from the amount Z (ml) of the 0.02N hydrochloric acid aqueous solution required for the titration, the number of moles Q of the substituent introduced by chemical modification is obtained by the following formula.
Q (mol) = 0.05 (N) × 10 (ml) / 1000
−0.02 (N) × Z (ml) / 1000
The relationship between the number of moles Q of the substituent and the chemical modification rate X (mol%) is calculated by the following formula (cellulose = (C ₆ O ₅ H ₁₀ ) _n = (162.14) _n , repetition Number of hydroxyl groups per unit = 3, molecular weight of OH = 17). In the following, T is the molecular weight of the substituent.

Solving this, it is as follows.

  The chemical modification rate of the cellulose fiber is preferably 65 mol% or less, more preferably 50 mol% or less, and still more preferably 40 mol% or less with respect to the total hydroxyl groups of cellulose.

  If this chemical modification rate is too high, the cellulose structure is destroyed and the crystallinity is lowered, so that there is a problem that the linear expansion coefficient of the obtained composite material becomes large, and it is colored after the chemical modification reaction. It is not preferable because it is not easy.

<Chemical modification of cellulose fiber membrane>
The chemical modification of the cellulose fiber membrane can take a normal method. That is, chemical modification can be performed by reacting cellulose in the cellulose fiber membrane with the above-described chemical modifier according to a conventional method. At this time, if necessary, a solvent or a catalyst may be used, or heating, decompression or the like may be performed. As the catalyst, it is preferable to use a basic catalyst such as pyridine, triethylamine, sodium hydroxide or sodium acetate, or an acidic catalyst such as acetic acid, sulfuric acid or perchloric acid.

As the temperature condition, if it is too high, there are concerns about yellowing of cellulose, a decrease in the degree of polymerization, and the like. The reaction time is several minutes to several tens of hours depending on the chemical modifier and the chemical modification rate.
After performing chemical modification in this way, it is preferable to wash thoroughly with water in order to terminate the reaction. If the unreacted chemical modifier remains, it is not preferable because it causes coloration later or becomes a problem when it is combined with the matrix material. In addition, after sufficiently washing with water, the remaining water is preferably replaced with an organic solvent such as alcohol. In this case, the cellulose fiber membrane can be easily replaced by immersing it in an organic solvent such as alcohol.

[Thickness of cellulose fiber membrane]
The thickness of the cellulose fiber membrane of the present invention is not particularly limited, but is preferably 10 μm or more, more preferably 50 μm or more, particularly preferably 80 μm or more, preferably 10 cm or less, more preferably 1 cm or less, more preferably It is 1 mm or less, and particularly preferably 250 μm or less. The thickness of the cellulose fiber membrane is preferably thicker than the above lower limit from the viewpoint of production stability and strength, and is preferably thinner than the upper limit from the viewpoint of productivity, uniformity and resin impregnation.

  In addition, the thickness of a cellulose fiber membrane can be calculated | required by the method described in the term of the calculation of the porosity of the following cellulose fiber membranes.

[Porosity of cellulose fiber membrane]
The cellulose fiber membrane of the present invention preferably has a porosity of 40 vol% or more, and more preferably 45 vol% or more and 60 vol% or less. When the porosity of the cellulose fiber membrane is small, it is difficult to impregnate a matrix material such as a resin, and an unimpregnated portion remains when a composite material is formed. Therefore, scattering occurs at the interface and haze increases, which is not preferable. In addition, when the porosity of the cellulose fiber membrane is large, a composite material is not preferable because a sufficient reinforcing effect by the cellulose fiber cannot be obtained and the linear expansion coefficient becomes large.

The porosity here refers to the volume ratio of the voids in the cellulose fiber membrane, and the porosity can be determined from the area, thickness, and weight of the cellulose fiber membrane according to the following formula.
Porosity (vol%) = {(1-B / (M × A × t)} × 100
Here, A is the area (cm ² ) of the cellulose fiber membrane, t (cm) is the thickness, B is the weight (g) of the cellulose fiber membrane, M is the density of the cellulose, and in the present invention, M = 1.5 g / Assume cm ³ . The film thickness of the cellulose fiber membrane is measured at 10 points at various positions of the cellulose fiber membrane using a film thickness meter (IP65 manufactured by Mitutoyo Co., Ltd.), and the average value is adopted.

  Moreover, when calculating | requiring the porosity of the cellulose fiber film | membrane in a composite material, a porosity can also be calculated | required by carrying out image analysis of spectral analysis and SEM observation of the cross section of a composite material.

[2] Compounding with Matrix Material Next, a method for producing the cellulose fiber composite material of the present invention by compositing a matrix material such as resin other than cellulose on the cellulose fiber membrane obtained as described above. To do.

[Refractive index of matrix material]
The matrix material used in the present invention is preferably a material having a refractive index (25 ° C.) of 1.45 or more for light having a wavelength of 587.6 nm. The refractive index of the matrix material is more preferably 1.50 or more. The refractive index of the matrix material is preferably 1.65 or less. The refractive index of the matrix material is more preferably 1.60 or less.

  If the refractive index of the matrix material is too large, the transmission efficiency of the composite material obtained due to excessive reflection becomes poor. Further, in both cases where the refractive index of the matrix material is too large and the refractive index is too small, the refractive index difference between the cellulose fiber and the matrix material becomes too large, and the resulting composite material has a large light scattering.

Here, the refractive index of the matrix material is measured by, for example, the following method.
<Refractive index of matrix material>
A cured resin having a thickness of 1 mm is cut into a 20 mm × 20 mm square, and the cut end is polished with a polisher or the like, and then a refractive index at a wavelength of 587.6 nm is set to a sample temperature of 25 ° C. using Kalnew KPR-2000 manufactured by Shimadzu Corporation. Measure at ± 0.1 ° C.

[Resin material]
Hereinafter, resin materials other than cellulose as the matrix material will be described. Examples of the resin material other than cellulose include at least one resin obtained from a thermoplastic resin, a thermosetting resin, a photocurable resin, and the like.

<Thermoplastic resin>
As thermoplastic resins, styrene resins, acrylic resins, aromatic polycarbonate resins, aliphatic polycarbonate resins, aromatic polyester resins, aliphatic polyester resins, aliphatic polyolefin resins, cyclic olefin resins, polyamides Resin, polyphenylene ether resin, thermoplastic polyimide resin, polyacetal resin, polysulfone resin, amorphous fluorine resin and the like.

  Examples of the styrenic resin include polymers and copolymers such as styrene, chlorostyrene, divinylbenzene, and α-methylstyrene.

  Examples of the acrylic resin include polymers and copolymers such as (meth) acrylic acid, (meth) acrylonitrile, (meth) acrylic acid ester, and (meth) acrylamide. Here, “(meth) acryl” means “acryl and / or methacryl”. Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters, (meth) acrylic acid monomers having a cycloalkyl ester group, and (meth) acrylic acid alkoxyalkyl esters. Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, ( Examples include benzyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, hydroxyethyl (meth) acrylate, and the like. Examples of the (meth) acrylic acid monomer having a cycloalkyl group include cyclohexyl (meth) acrylate and isobornyl (meth) acrylate. Examples of (meth) acrylic acid alkoxyalkyl esters include 2-methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and 2-butoxyethyl (meth) acrylate. (Meth) acrylamides include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N -N-substituted (meth) acrylamides such as isopropyl (meth) acrylamide, Nt-octyl (meth) acrylamide and the like.

  Aromatic polycarbonate resin is produced by reaction of one or more bisphenols that can contain polyhydric phenols having 3 or more valences as a copolymerization component with carbonate esters such as bisalkyl carbonate, bisaryl carbonate, and phosgene. In order to make aromatic polyester carbonates as required, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid or derivatives thereof (for example, aromatic dicarboxylic acid diesters and aromatic dicarboxylic acids) Acid chloride) may be used.

  Examples of the bisphenols include bisphenol A, bisphenol C, bisphenol E, bisphenol F, bisphenol M, bisphenol P, bisphenol S, and bisphenol Z (for abbreviations refer to the Aldrich reagent catalog), among which bisphenol A and bisphenol Z (Where the central carbon participates in the cyclohexane ring) is preferred, and bisphenol A is particularly preferred. Examples of copolymerizable trihydric phenols include 1,1,1- (4-hydroxyphenyl) ethane and phloroglucinol.

  The aliphatic polycarbonate resin is a copolymer produced by a reaction between an aliphatic diol component and / or an alicyclic diol component and a carbonic ester such as bisalkyl carbonate or phosgene. Examples of the alicyclic diol include cyclohexanedimethanol and isosorbite.

  Examples of aromatic polyester resins include copolymers of diols such as ethylene glycol, propylene glycol, and 1,4-butanediol and aromatic carboxylic acids such as terephthalic acid. Moreover, the copolymer of diols, such as bisphenol A, and aromatic carboxylic acids, such as a terephthalic acid and isophthalic acid, is also mentioned like a polyarylate.

  Examples of the aliphatic polyester resin include a copolymer of the diol and an aliphatic dicarboxylic acid such as succinic acid and valeric acid, and a copolymer of hydroxydicarboxylic acid such as glycolic acid and lactic acid.

  Specific examples of the aliphatic polyolefin resin include homopolymers of α-olefins having about 2 to 8 carbon atoms such as ethylene, propylene and 1-butene, those α-olefins, ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, Binary or ternary copolymers with other α-olefins having about 2 to 18 carbon atoms such as 1-octene, 1-decene, 1-octadecene, etc .; specifically, for example, branched low density Ethylene homopolymers such as polyethylene and linear high-density polyethylene, ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-propylene-1-butene copolymers, ethylene Ethylene resins such as -4-methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-heptene copolymer, ethylene-1-octene copolymer, propylene homopolymer, propylene -Propylene-based resins such as ethylene copolymer, propylene-ethylene-1-butene copolymer, 1-butene homopolymer, 1-butene-ethylene copolymer, 1-butene-propylene copolymer, etc. Butene-based resins, 4-methyl-1-pentene homopolymers, 4-methyl-1-pentene-based resins such as 4-methyl-1-pentene-ethylene copolymers, and ethylene and other α -Copolymers with olefins, copolymers of 1-butene with other α-olefins, such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl 1,4-hexadiene, 6-methyl-1,5-heptadiene, 1,4-octadiene, 7-methyl-1,6-octadiene, cyclohexadiene, cyclooctadiene, dicyclopentadiene, 5-methylene-2-norbornene A binary or ternary copolymer with a nonconjugated diene such as 5-ethylidene-2-norbornene, 5-butylidene-2-norbornene, 5-isopropenyl-2-norbornene, and the like. -Olefin rubbers such as a propylene copolymer, an ethylene-propylene-nonconjugated diene copolymer, an ethylene-1-butene copolymer, and an ethylene-1-butene-nonconjugated diene copolymer. Two or more olefin polymers may be used in combination.

  The cyclic olefin-based resin is a polymer containing a cyclic olefin skeleton in a polymer chain, such as norbornene or cyclohexadiene, or a copolymer containing these. For example, a norbornene-based resin composed of a repeating unit of a norbornene skeleton or a copolymer of a norbornene skeleton and a methylene skeleton can be mentioned, and commercially available products include “Arton” manufactured by JSR, “Xennex” and “Zeonor” manufactured by Nippon Zeon. "Apel" manufactured by Mitsui Chemicals, "Topas" manufactured by Chicona, and the like.

  Examples of polyamide resins include aliphatic amide resins such as 6,6-nylon, 6-nylon, 11-nylon, 12-nylon, 4,6-nylon, 6,10-nylon, 6,12-nylon, An aromatic polyamide such as an aromatic diamine such as phenylenediamine and an aromatic dicarboxylic acid such as terephthaloyl chloride or isophthaloyl chloride or a derivative thereof may be used.

  Examples of the polyphenylene ether resin include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2,6-dichloro ether). -1,4-phenylene ether), and a copolymer of 2,6-dimethylphenol and other phenols.

  Examples of polyimide resins include pyromellitic acid type imides such as polymellitic anhydride and 4,4′-diaminodiphenyl ether, aromatic diamines such as anhydrous trimellitic acid chloride and p-phenylenediamine, and diisocyanate compounds. From the copolymer of trimellitic acid type polyimide, biphenyltetracarboxylic acid, 4,4′-diaminodiphenyl ether, p-phenylenediamine, etc., benzophenone tetracarboxylic acid, 4,4′-diaminodiphenyl ether, etc. Benzophenone-type polyimide, bismaleimide, bismaleimide-type polyimide made of 4,4′-diaminodiphenylmethane, and the like.

  Examples of the polyacetal resin include a homopolymer having an oxymethylene structure as a unit structure and a copolymer containing an oxyethylene unit.

  Examples of the polysulfone resin include copolymers such as 4,4'-dichlorodiphenylsulfone and bisphenol A.

  Examples of the amorphous fluorine-based resin include homopolymers or copolymers such as tetrafluoroethylene, hexafluoropropylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, and perfluoroalkyl vinyl ether.

  These thermoplastic resins may be used individually by 1 type, and may use 2 or more types together.

<Curable resin>
The thermosetting resin and the light curable resin mean a precursor before curing or a cured resin obtained by curing. Here, the precursor means a substance that is liquid, semi-solid or solid at room temperature and exhibits fluidity at room temperature or under heating. These can be insoluble and infusible resins formed by forming a network-like three-dimensional structure while increasing the molecular weight by causing a polymerization reaction or a crosslinking reaction by the action of a curing agent, a catalyst, heat or light. The resin cured product means a resin obtained by curing the thermosetting resin precursor or the photocurable resin precursor.

<< Thermosetting resin >>
The thermosetting resin in the present invention is not particularly limited, but epoxy resin, acrylic resin, oxetane resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, silicon resin, polyurethane resin, diallyl phthalate Examples thereof include precursors such as resins.

  The epoxy resin precursor refers to an organic compound having at least one epoxy group. The number of epoxy groups in the epoxy resin precursor is preferably 1 or more and 7 or less per molecule, and more preferably 2 or more per molecule. Here, the number of epoxy groups per molecule of the precursor is obtained by dividing the total number of epoxy groups in the epoxy resin precursor by the total number of molecules in the epoxy resin. It does not specifically limit as said epoxy resin precursor, For example, the epoxy resin etc. which were shown below are mentioned. These epoxy resins may be used alone or in combination of two or more. These epoxy resins are obtained by curing a thermosetting resin precursor using a curing agent.

  For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol type epoxy resin such as bisphenol S type epoxy resin, novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, etc. And aromatic epoxy resins such as trisphenolmethane triglycidyl ether and precursors such as hydrogenated products and brominated products thereof. 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexyl-3,4-epoxy-2-methylcyclohexanecarboxylate, bis (3,4-epoxy Cycloaliphatic epoxy resins such as (cyclohexyl) adipate, bis (3,4-epoxycyclohexyl) methyl adipate, bis (3,4-epoxy-6-methylcyclohexyl) methyl adipate, bis (2,3-epoxycyclopentyl) ether Can be mentioned. Also, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl Examples thereof include aliphatic epoxy resins such as polyglycidyl ethers of ethers and long-chain polyols containing polyoxyalkylene glycols containing 2 to 9 (preferably 2 to 4) carbon atoms, preferably polyoxyalkylene glycols and polytetramethylene ether glycols. . In addition, glycidyl ester type epoxy resins such as phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexadrophthalic acid diglycidyl ester, diglycidyl-p-oxybenzoic acid, glycidyl ether-glycidyl ester of salicylic acid, dimer acid glycidyl ester, etc. And hydrogenated products thereof. Further, triglycidyl isocyanurate, N, N′-diglycidyl derivative of cyclic alkylene urea, glycidyl amine type epoxy resin of N, N, O-triglycidyl derivative of p-aminophenol, and hydrogenated products thereof can be mentioned. Moreover, the copolymer etc. of radical polymerizable monomers, such as glycidyl (meth) acrylate, ethylene, vinyl acetate, (meth) acrylic acid ester, etc. are mentioned. In addition, a polymer mainly composed of a conjugated diene compound such as epoxidized polybutadiene or a partially hydrogenated polymer obtained by epoxidizing an unsaturated carbon double bond may be used. Further, a polymer block mainly composed of a vinyl aromatic compound, such as epoxidized SBS, and a polymer block mainly composed of a conjugated diene compound or a polymer block of a partially hydrogenated product thereof are contained in the same molecule. Examples include epoxidized unsaturated carbon double bonds of a conjugated diene compound in a block copolymer. Moreover, the polyester resin etc. which have 1 or more per molecule, Preferably 2 or more epoxy group are mentioned. Examples thereof include urethane-modified epoxy resins and polycaprolactone-modified epoxy resins in which urethane bonds and polycaprolactone bonds are introduced into the structure of the epoxy resin. Examples of the modified epoxy resin include a rubber modified epoxy resin in which a rubber component such as NBR, CTBN, polybutadiene, and acrylic rubber is contained in the epoxy resin. In addition to the epoxy resin, a resin or oligomer having at least one oxirane ring may be added. Moreover, the thermosetting resin and composition containing a fluorene containing epoxy resin, a fluorene group, or its hardened | cured material is also mentioned. These fluorene-containing epoxy resins are suitably used because of their high heat resistance. The curing agent used for the curing reaction of the epoxy resin precursor is not particularly limited. For example, amine compounds, compounds such as polyaminoamide compounds synthesized from amine compounds, tertiary amine compounds, imidazole compounds, hydrazide compounds, Examples include melamine compounds, acid anhydrides, phenol compounds, thermal latent cationic polymerization catalysts, photolatent cationic polymerization initiators, dicyanamide and derivatives thereof. These hardening | curing agents may be used independently and 2 or more types may be used together.

The acrylic resin precursor includes a monofunctional (meth) acrylate compound having one (meth) acryloyl group in the molecule, and a polyfunctional (meth) acrylate having two or three (meth) acryloyl groups in the molecule. Examples thereof include compounds, styrene compounds, acrylic acid derivatives, acrylate compounds having 4 to 8 (meth) acryloyl groups in the molecule, epoxy (meth) acrylate compounds, and (meth) acrylate compounds having a urethane bond.
Monofunctional (meth) acrylate compounds having one (meth) acryloyl group in the molecule include methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, Examples include cyclohexyl (meth) acrylate.

In particular, mono (meth) acrylate having an alicyclic skeleton has high heat resistance and can be suitably used. Specific examples of the alicyclic skeleton mono (meth) acrylate compound include (hydroxy-acryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, (hydroxy-methacryloyloxy) tricyclo [5.2.1]. .0 ^2,6] decane, (hydroxy - acryloyloxy) pentacyclo [6.5.1.1 ^{3, 6.} 0 ^2,7 . 0 ^9,13 ] pentadecane, (hydroxy-methacryloyloxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (hydroxymethyl-acryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, (hydroxymethyl-methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 Decane, (hydroxymethyl-acryloyloxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (hydroxymethyl-methacryloyloxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (hydroxyethyl-acryloyloxyethyl) tricyclo [5.2.1.0 ^2,6 ] decane, (hydroxyethyl-methacryloyloxyethyl) tricyclo [5.2.1.0 ^2,6 ] Decane, (hydroxyethyl-acryloyloxyethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (hydroxyethyl-methacryloyloxyethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane and the like. Moreover, these mixtures etc. can be mentioned.

Polyfunctional (meth) acrylate compounds having 2 or 3 (meth) acryloyl groups in the molecule include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, tetraethylene glycol or higher, 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy 1,3-di (meth) acryloxypropane, 2,2-bis [4- (meth) acryloyloxyphenyl] propane, trimethylolpropane tri (meth) acrylate, bis (hydroxy) tricyclo [5.2.1. 0 ^2,6] decane Diacrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^{2, 6]} decane = dimethacrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^{2, 6]} decane = acrylate methacrylate, bis (hydroxy ) Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = diacrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = dimethacrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = acrylate methacrylate, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) phenyl] propane, 2,2-bis [4- (β- (meth) acryloyloxyethoxy) Cyclohexyl] propane, 1,4-bis [(meth) acryloyloxymethyl] cyclohexane and the like.

  Examples of the styrene compound include styrene, chlorostyrene, divinylbenzene, and α-methylstyrene.

  Examples of (meth) acrylic acid derivatives other than esters include acrylamide, methacrylamide, acrylonitrile, methacrylonitrile and the like.

Among these, an alicyclic ring skeleton bis (meth) acrylate compound is preferably used.
For example, bis (acryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, bis (methacryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, (acryloyloxy-methacryloyloxy) tricyclo [ 5.2.1.0 ^2,6 ] decane, bis (acryloyloxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, bis (methacryloyloxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (acryloyloxy-methacryloyloxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, bis (acryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, bis (methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, ( Acryloyloxymethyl-methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, bis (acryloyloxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, bis (methacryloyloxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (acryloyloxymethyl-methacryloyloxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, bis (acryloyloxyethyl) tricyclo [5.2.1.0 ^2,6 ] decane, bis (methacryloyloxyethyl) tricyclo [5.2.1.0 ^2,6 ] decane, ( Acryloyloxyethyl-methacryloyloxyethyl) tricyclo [5.2.1.0 ^2,6 ] decane, bis (acryloyloxyethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, bis (methacryloyloxyethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, (acryloyloxyethyl-methacryloyloxyethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane, etc., and mixtures thereof.

Of these, bis (acryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, bis (methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane and (acryloyloxymethyl) -Methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane is preferred. Several of these bis (meth) acrylates can be used in combination.

  As the (meth) acrylate having 4 to 8 (meth) acryloyl groups in the molecule, (meth) acrylic acid ester of polyol can be used. Specifically, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol tetra (meth) acrylate, Dipentaerythritol tri (meth) acrylate, tripentaerythritol octa (meth) acrylate, tripentaerythritol septa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, tripentaerythritol tetra ( And (meth) acrylate, tripentaerythritol tri (meth) acrylate, and the like.

  Next, specific examples of the epoxy (meth) acrylate include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, compound having an alicyclic epoxy group, bisphenol A type propylene oxide addition type. Examples include a reaction product of terminal glycidyl ether, fluorene epoxy resin, and (meth) acrylic acid. Specifically, bisphenol A diglycidyl ether = di (meth) acrylate, bisphenol A dipropylene oxide diglycidyl ether = di (meth) acrylate, ethylene glycol diglycidyl ether = di (meth) acrylate, propylene glycol diglycidyl ether = di (Meth) acrylate, neopentyl glycol diglycidyl ether = di (meth) acrylate, 1,6-hexanediol diglycidyl ether = di (meth) acrylate, glycerin diglycidyl ether = di (meth) acrylate, trimethylolpropane triglycidyl Ether = tri (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate , 3,4-epoxycyclohexyl ethyl (meth) acrylate, 3,4-epoxycyclohexyl-butyl (meth) acrylate, 3,4-epoxycyclohexylmethyl-amino (meth) acrylate.

  Examples of the (meth) acrylate having a urethane bond in the molecule include urethane oligomers having 2 to 10 (preferably 2 to 5) (meth) acryloyl groups in one molecule. For example, there is a (meth) acryloyl group-containing urethane oligomer produced by reacting a urethane prepolymer obtained by reacting diols and diisocyanates with a hydroxy group-containing (meth) acrylate.

  The diols used here include ring-opening copolymerization of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, or two or more ion-polymerizable cyclic compounds. Examples include polyether diols obtained. Examples of the ion polymerizable cyclic compound include ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, Examples include cyclic ethers such as allyl glycidyl ether, allyl glycidyl carbonate, butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyl tetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and benzoic acid glycidyl ester. Further, a polyether obtained by ring-opening copolymerization of the ionic polymerizable cyclic compound with a cyclic imine such as ethyleneimine, a cyclic lactone acid such as β-propiolactone or glycolic acid lactide, or dimethylcyclopolysiloxane. Diols can also be used. Specific combinations of the two or more ion-polymerizable cyclic compounds include tetrahydrofuran and propylene oxide, tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, butene oxide and ethylene oxide. Etc. The ring-opening copolymer of these ion-polymerizable cyclic compounds may be bonded at random or may be bonded in a block form.

  These polyether diols described so far include, for example, PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical Corporation), PPG1000, EXCENOL2020, 1020 (manufactured by Asahi Ohrin Co., Ltd.), PEG1000, Unisafe DC1100, DC1800 ( As described above, manufactured by NOF Corporation), PPTG2000, PPTG1000, PTG400, PTGL2000 (above, manufactured by Hodogaya Chemical Co., Ltd.), Z-3001-4, Z-3001-5, PBG2000A, PBG2000B (above, Daiichi Kogyo Seiyaku Co., Ltd.) It can also be obtained as a commercial product such as (made by Co., Ltd.).

  In addition to the above polyether diols, polyester diols, polycarbonate diols, polycaprolactone diols and the like can be mentioned, and these diols can be used in combination with polyether diols. The polymerization mode of these structural units is not particularly limited, and may be any of random polymerization, block polymerization, and graft polymerization. Examples of the polyester diol used here include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3 -Polyhydric alcohols such as methyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol and phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid And polyester polyols obtained by reacting with a polybasic acid such as sebacic acid. Commercially available products include Kurapol P-2010, PMIPA, PKA-A, PKA-A2, PNA-2000 (above, manufactured by Kuraray Co., Ltd.) and the like.

  Examples of the polycarbonate diol include 1,6-hexane polycarbonate, and commercially available products include DN-980, 981, 982, 983 (manufactured by Nippon Polyurethane Co., Ltd.), PC-8000 (US PPG ( Etc.).

  Furthermore, as polycaprolactone diol, for example, ε-caprolactone and ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, 1,6-hexanediol, neo Examples thereof include polycaprolactone diols obtained by reacting divalent diols such as pentyl glycol, 1,4-cyclohexanedimethanol and 1,4-butanediol. These diols are commercially available from Plaxel 205, 205AL, 212, 212AL, 220, 220AL (above, manufactured by Daicel Corporation).

  Many diols other than those described above can also be used. Examples of such diols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, and bisphenol A. Ethylene oxide addition diol, bisphenol A butylene oxide addition diol, bisphenol F ethylene oxide addition diol, bisphenol F butylene oxide addition diol, hydrogenated bisphenol A ethylene oxide addition diol, hydrogenated bisphenol A butylene oxide addition diol, water Bisphenol F ethylene oxide addition diol, hydrogenated bisphenol F butylene oxide addition diol, dicyclopentadiene dimethylol compound , Tricyclodecane dimethanol, β-methyl-δ-valerolactone, hydroxy-terminated polybutadiene, hydroxy-terminated hydrogenated polybutadiene, castor oil-modified polyol, polydimethylsiloxane-terminated diol compound, polydimethylsiloxane carbitol-modified polyol, etc. .

  In addition to using the diol as described above, it is also possible to use a diamine together with a diol having a polyoxyalkylene structure. Examples of such a diamine include ethylenediamine, tetramethylenediamine, hexamethylenediamine, and paraphenylenediamine. Diamines such as 4,4'-diaminodiphenylmethane, diamines containing heteroatoms, polyether diamines, and the like.

  Preferable diol includes polytetramethylene ether glycol which is a polymer of 1,4-butanediol. The preferred molecular weight of this diol is usually 50 to 15,000 in terms of number average molecular weight, particularly 500 to 3,000.

  On the other hand, examples of diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, and m-phenylene. Diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenyl metadiisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1, 6-hexamethylene diisocyanate, methylene dicyclohexyl diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate, 1,4 Hexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, isophorone diisocyanate, norbornane diisocyanate, lysine diisocyanate, and the like. These diisocyanates may be used singly or in combination of two or more. Of these, diisocyanates having an alicyclic skeleton such as isophorone diisocyanate, norbornane diisocyanate, and methylene dicyclohexyl diisocyanate are preferably used.

  Examples of the hydroxy group-containing (meth) acrylate compound used in the reaction include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3- Phenyloxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) Acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipenta Risuri penta (meth) acrylate, further the alkyl glycidyl ether, allyl glycidyl ether, may also include compounds obtained by addition reaction of glycidyl (meth) glycidyl group-containing compounds such as acrylates and (meth) acrylic acid. Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are particularly preferable.

  Commercially available urethane oligomers include EB2ECRYL220 (Daicel Cytec), Art Resin UN-3320HA (Negami Kogyo), Art Resin UN-3320HB (Negami Kogyo), Art Resin UN-3320HC (Negami Kogyo), Art Resin UN-330 ( Negami Kogyo) and Art Resin UN-901T (Negami Kogyo), NK-oligo U-4HA (Shin Nakamura Chemical), NK-oligo U-6HA (Shin Nakamura Chemical), NK-oligo U-324A (Shin Nakamura Chemical), NK-oligo U-15HA (Shin Nakamura Chemical), NK-oligo U-108A (Shin Nakamura Chemical), NK-oligo U-200AX (Shin Nakamura Chemical), NK-oligo U-122P (Shin Nakamura Chemical), NK- Oligo U-5201 (Shin Nakamura Chemical), NK-Oligo U-340AX (Shin Nakamura Chemical), NK-Oligo U-511 (Shin Nakamura Chemical), NK-Oligo U-512 (Shin Nakamura Chemical), NK-Oligo U -311 (Shin Nakamura Chemical), NK-oligo UA-W1 (Shin Nakamura Chemical), NK-oligo UA-W2 (Shin Nakamura Chemical), NK-oligo UA-W3 (Shin Nakamura Chemical), NK-oligo UA-W4 (Shin Nakamura Chemical , NK-oligo UA-4000 (Shin-Nakamura Chemical), NK-oligo UA-100 (Shin-Nakamura Chemical), Purple light UV-1400B (Nippon Synthetic Chemical Industry), Purple light UV-1700B (Nippon Synthetic Chemical Industry), Purple light UV- 6300B (Nippon Synthetic Chemical Industry), purple light UV-7550B (Nippon Synthetic Chemical Industry), purple light UV-7600B (Nippon Synthetic Chemical Industry), purple light UV-7605B (Nippon Synthetic Chemical Industry), purple light UV-7610B (Nippon Synthetic Chemical Industry) ), Purple light UV-7620EA (Nippon Synthetic Chemical Industry), purple light UV-7630B (Nippon Synthetic Chemical Industry), purple light UV-7640B (Nippon Synthetic Chemical Industry), purple light UV-6630B (Nippon Synthetic Chemical Industry), purple light UV-7000B (Nippon Synthetic Chemical Industry), Purple Light UV-7510B (Nippon Synthetic Chemical Industry), Purple Light UV-7461TE (Nippon Synthetic Chemical Industry), Purple Light UV-3000B (Nippon Synthetic Chemical Industry), Purple Light UV-3200B (Nippon Synthetic Chemical Industry) , Purple light UV-3210EA (Nippon Synthetic Chemical Industry), purple light UV-3310B (Nippon Synthetic Chemical Industry), purple light UV-3500BA (Nippon Synthetic Chemical Industry), purple light UV-3520T L (Nippon Synthetic Chemical Industry), purple light UV-3700B (Nippon Synthetic Chemical Industry), purple light UV-6100B (Nippon Synthetic Chemical Industry), purple light UV-6640B (Nippon Synthetic Chemical Industry), etc. can be used.

  The number average molecular weight of the (meth) acrylate having a urethane bond in the molecule is preferably 1,000 to 100,000, and more preferably 2,000 to 10,000. Among them, urethane acrylate having methylene dicyclohexyl diisocyanate and polytetramethylene ether glycol is excellent in terms of transparency, low birefringence, flexibility, and the like, and can be suitably used.

  Examples of the oxetane resin precursor include compounds having at least one oxetane ring. The number of oxetane rings in the oxetane resin precursor is preferably 1 or more and 4 or less per molecule. Examples of the compound having one oxetane in the molecule include 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, and 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane. , 3-ethyl {[-3- (triethoxylyl) propoxy] methyl} oxetane, 3-ethyl-3-methacryloxymethyloxetane, and the like. Compounds having two oxetanes in the molecule include di [1-ethyl (3-oxetanyl)] methyl ether, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 4 , 4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, and the like. Examples of the compound having 3 to 4 oxetane rings include a branched polyalkyleneoxy group and a reaction product of a polysiloxy group and 3-alkyl-3-methyloxetane.

  Examples of the phenol resin include those obtained by reacting phenols such as phenol and cresol with formaldehyde and the like to synthesize novolak and the like and curing it with hexamethylenetetramine or the like.

  Examples of the urea resin include urea and a polymerization reaction product such as formaldehyde.

  Examples of the melamine resin include polymerization reaction products such as melamine and formaldehyde.

Examples of the unsaturated polyester resin include a resin obtained by dissolving an unsaturated polyester obtained from an unsaturated polybasic acid or the like and a polyhydric alcohol or the like in a monomer to be polymerized therewith, and the like.
Examples of the silicon resin precursor include those having an organopolysiloxane as a main skeleton.
Examples of the polyurethane resin precursor include polymerization reaction products composed of diols such as glycol and diisocyanate.

  Examples of diallyl phthalate resins include reactants comprising diallyl phthalate monomers and diallyl phthalate prepolymers.

  The thermosetting resin curing agent and curing catalyst are not particularly limited. For example, amine compounds, compounds such as polyaminoamide compounds synthesized from amine compounds, tertiary amine compounds, imidazole compounds, hydrazide compounds, melamine compounds. , Acid anhydrides, phenol compounds, thermal latent cationic polymerization catalysts, dicyanamide and derivatives thereof. These can be used alone or as a mixture of two or more.

<< Photo-curing resin >>
Although it does not specifically limit as photocurable resin in this invention, Precursors, such as an epoxy resin illustrated in the description of the above-mentioned thermosetting resin, an acrylic resin, and an oxetane resin, are mentioned.

  Although there is no limitation in particular as a hardening | curing agent of these photocurable resins, For example, a diaryl iodonium salt, a triaryl sulfonium salt, etc. are mentioned.

  The thermosetting resin and the photocurable resin described so far are used as a curable composition appropriately blended with a chain transfer agent, an ultraviolet absorber, a filler, a silane coupling agent and the like.

  The curable composition may contain a chain transfer agent for the purpose of causing the reaction to proceed uniformly. For example, a polyfunctional mercaptan compound having two or more thiol groups in the molecule can be used, and thereby moderate toughness can be imparted to the cured product. Examples of mercaptan compounds include pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (β-thioglycolate), trimethylolpropane tris (β-thiopropionate), trimethylolpropane tris (β-thiol). Glycolate), diethylene glycol bis (β-thiopropionate), diethylene glycol bis (β-thioglycolate), dipentaerythritol hexakis (β-thiopropionate), dipentaerythritol hexakis (β-thioglycolate) 2) to 6-valent thioglycolic acid ester or thiopropionic acid ester; tris [2- (β-thiopropionyloxy) ethyl] triisocyanurate, tris [2- (β-thioglyconyloxy) ethyl] triisocyanur Tris [2- (β-thiopropionyloxyethoxy) ethyl] triisocyanurate, tris [2- (β-thioglyconyloxyethoxy) ethyl] triisocyanurate, tris [2- (β-thiopropionyloxy) ) Propyl] triisocyanurate, tris [2- (β-thioglyconyloxy) propyl] triisocyanurate, and other ω-SH group-containing triisocyanurates; benzene dimercaptan, xylylene dimercaptan, 4, 4′-dimercapto Examples include α, ω-SH group-containing compounds such as diphenyl sulfide. Among these, one kind such as pentaerythritol tetrakis (β-thiopropionate), trimethylolpropane tris (β-thiopropionate), tris [2- (β-thiopropionyloxyethoxy) ethyl] triisocyanurate or the like Two or more are preferably used. When a mercaptan compound is added, it is usually contained at a ratio of 30% by weight or less with respect to the total of radically polymerizable compounds.

  For the purpose of preventing coloring, the curable composition may contain an ultraviolet absorber. For example, the ultraviolet absorber is selected from a benzophenone ultraviolet absorber and a benzotriazole ultraviolet absorber, and the ultraviolet absorber may be used alone or in combination of two or more. . Specifically, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, 2,2′-dihydroxy-4 Benzophenone compounds such as -methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2- (2'-hydroxy-5-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ' , 5′-ditertiarybutylphenyl) benzotriazole, benzotriazole compounds such as 2- (2′-hydroxy-3′-tertiarybutyl-5′-methylphenyl) benzotriazole, and other malonate ester hostabin PR -25 (Clariant , Oxalic acid anilide-based San Dubois VSU (Clariant) is a compound such. When an ultraviolet absorber is added, it is usually contained at a ratio of 0.01 to 1 part by weight with respect to a total of 100 parts by weight of the radical polymerizable compound.

  Moreover, you may contain fillers other than a cellulose. Examples thereof include inorganic particles and organic polymers. Specific examples include inorganic particles such as silica particles, titania particles and alumina particles, transparent cycloolefin polymers such as Zeonex (Nippon Zeon) and Arton (JSR), and general-purpose thermoplastic polymers such as polycarbonate and PMMA. . Among these, use of nano-sized silica particles is preferable because transparency can be maintained. In addition, it is preferable to use a polymer having a structure similar to that of the ultraviolet curable monomer because the polymer can be dissolved to a high concentration.

  Moreover, you may add a silane coupling agent. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-((meth) acryloxypropyl) trimethoxysilane, β- (3 , 4epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like.Among them, γ-((meth) acryloxypropyl) trimethoxysilane, γ-((meth) acryloxypropyl) methyldimethoxysilane, γ-((meth) acryloxypropyl) methyldiethoxysilane, γ-((meta ) Acryloxypropyl) triethoxysilane, γ- (acryloxypropyl) trimethoxysilane, etc. have (meth) acrylic or acrylic groups in the molecule, and other monomers in the curable composition according to the present invention Is preferable because it can be copolymerized. A silane coupling agent is contained so that it may become 0.1 to 50 weight part normally with respect to a total of 100 weight part of a radically polymerizable compound. The amount is preferably 1 part by weight or more and 20 parts by weight or less, particularly preferably 1 part by weight or more and 20 parts by weight or less. When the amount is less than 0.1 part by weight, the effect of containing this is not sufficiently obtained. When the amount is more than 50 parts by weight, optical properties such as transparency of the cured product may be impaired. .

The curable composition for combining the resin with the cellulose fiber membrane can be polymerized and cured by a known method to obtain a cured product.
For example, heat curing or radiation curing can be used. Radiation curing is preferable. Examples of the radiation include infrared rays, visible rays, ultraviolet rays, electron beams, and the like, preferably light. More preferred is light having a wavelength of about 200 nm to 450 nm, and even more preferred is ultraviolet light having a wavelength of 300 to 400 nm.

  Specifically, a method in which a thermal polymerization initiator that generates radicals upon heating is added to the curable composition in advance and polymerized by heating (hereinafter sometimes referred to as “thermal polymerization”), the curable composition in advance. A photopolymerization initiator that generates radicals by radiation such as ultraviolet rays is added to the polymer, and a method of polymerizing by irradiation with radiation (hereinafter sometimes referred to as “photopolymerization”), etc., and a thermal polymerization initiator and photopolymerization start Examples include a method of adding in advance using a combination of free and polymerizing by a combination of heat and light. In the present invention, photopolymerization is more preferable.

  As the photopolymerization initiator, a photoradical generator is usually used. As the photoradical generator, a known compound that can be used for this purpose can be used. Examples include benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and the like. Among these, 2,4,6-trimethylbenzoyldiphenylphosphine oxide is preferable. These photopolymerization initiators may be used alone or in combination of two or more.

  The component amount of the photopolymerization initiator is 0.001 part by weight or more, preferably 0.01 part by weight or more, more preferably 0.001 part by weight, when the total amount of the photocurable resin in the curable composition is 100 parts by weight. 05 parts by weight or more. The upper limit is usually 1 part by weight or less, preferably 0.5 part by weight or less, more preferably 0.1 part by weight or less. When the addition amount of the photopolymerization initiator is too large, the polymerization proceeds rapidly, and not only the birefringence of the resulting cured product is increased, but also the hue is deteriorated. For example, when the concentration of the initiator is 5 parts by weight, the unabsorbed part is generated because the light cannot reach the opposite side of the ultraviolet irradiation due to the absorption of the initiator. Further, it is colored yellow and the hue is markedly deteriorated. On the other hand, if the amount is too small, the polymerization may not proceed sufficiently even if ultraviolet irradiation is performed.

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

[Composite method of cellulose fiber membrane and matrix material]
The method for obtaining the cellulose fiber composite material of the present invention by compounding the resin with the cellulose fiber membrane of the present invention is not particularly limited, but the cellulose fiber membrane of the present invention is impregnated with a resin monomer of the matrix material and polymerized. Method: a method of impregnating the cellulose fiber membrane of the present invention with a thermosetting resin precursor or a photocurable resin precursor and curing; a method of impregnating the cellulose fiber membrane of the present invention with a resin solution of a matrix material and drying; Examples include a method in which the cellulose fiber membrane of the present invention is closely adhered by a hot press or the like;

  As a method for polymerizing cellulose fiber membrane by impregnating the monomer, a method for obtaining a composite material by impregnating the cellulose fiber membrane with a thermoplastic resin monomer and, if necessary, a polymerization catalyst or an initiator and polymerizing by heating or the like. Is mentioned.

As a method of impregnating and curing a thermosetting resin precursor or a photocurable resin precursor, a mixture of a thermosetting resin precursor such as an epoxy resin or a photocurable resin precursor such as an acrylic resin and a curing agent is used. And a method of obtaining a composite material by impregnating a cellulose fiber membrane and curing the thermosetting resin precursor or the photocurable resin precursor with heat or light. In this case, the amount of radiation to be irradiated is arbitrary as long as the photopolymerization initiator generates radicals. However, when the amount is extremely small, the polymerization is incomplete, and the cured product has sufficient heat resistance and mechanical properties. In contrast, if it is excessively excessive, the cured product will be deteriorated by light such as yellowing. Therefore, ultraviolet rays having a wavelength of 300 to 450 nm are used in accordance with the composition of the monomer and the type and amount of the photopolymerization initiator. preferably irradiated with 0.1 J / cm ² or more 200 J / cm ² or less. More preferably, irradiation is performed in the range of 1 J / cm ² or more and 20 J / cm ² . More preferably, the radiation is divided into a plurality of times. That is, when the first irradiation is performed for about 1/20 to 1/3 of the total irradiation amount and the necessary remaining amount is irradiated for the second and subsequent times, a cured product with smaller birefringence is obtained. Specific examples of the lamp to be used include a metal halide lamp, a high pressure mercury lamp lamp, an ultraviolet LED lamp and the like.
For the purpose of promptly completing the polymerization, photopolymerization and thermal polymerization may be performed simultaneously. In this case, the curable composition is heated and cured in the range of 30 ° C. or more and 300 ° C. or less simultaneously with the radiation irradiation. In this case, a thermal polymerization initiator may be added to the curable composition in order to complete the polymerization, but if added in a large amount, the birefringence of the cured product is increased and the hue is deteriorated. The agent is generally used in an amount of 0.1 to 2 parts by weight, more preferably 0.3 to 1 part by weight, based on 100 parts by weight of the total amount of monomers.

  A method of obtaining a composite material by impregnating a resin solution and drying and then closely adhering with a heating press or the like is performed by dissolving a resin in a solvent in which the resin dissolves, impregnating the solution into a cellulose fiber membrane, and drying the solution. Is mentioned. In this case, after drying, a higher performance composite material can be obtained by closely adhering the voids in which the solvent is dried by a heating press or the like.

  As a method of impregnating a melt of a thermoplastic resin and adhering it with a hot press, etc., the thermoplastic resin is melted at a temperature equal to or higher than its glass temperature or melting point, impregnated into a cellulose fiber film, and adhered with a hot press or the like. A method can be mentioned.

  A plurality of composite materials produced in this way can be stacked to form a laminate. A thick film can be formed by applying a heat press treatment to the laminate. The thick film composite material thus obtained can be used as a glazing or structural material.

[3] Physical properties of cellulose fiber composite material The physical properties or preferred physical properties of the cellulose fiber composite material of the present invention will be described below.

[Cellulose fiber content]
The cellulose fiber content of the cellulose fiber composite material of the present invention is 40% by weight or more. The cellulose fiber content of the cellulose fiber composite material of the present invention is preferably 45% by weight or more, 70% by weight or less, more preferably 60% by weight or less. When the cellulose fiber content of the cellulose fiber composite material is too small, there is a problem that the number of bonds between the cellulose fibers is reduced and the strength of the composite material is lowered. On the other hand, if the cellulose fiber content is too high, it becomes difficult for the matrix material to be uniformly compounded in the gaps formed between the cellulose fibers, light scattering increases, and the uniformity is reduced and the composite material is distorted. There is a problem that occurs.

  The content of the matrix material in the cellulose fiber composite material of the present invention is preferably 60% by weight or less, more preferably 55% by weight or less, preferably 30% by weight or more, and more preferably 40% by weight. % Or more. If the content of the matrix material in the cellulose fiber composite material is too small, it will be difficult to uniformly composite the matrix material in the voids formed between the cellulose fibers, resulting in increased light scattering and a decrease in uniformity, resulting in a composite material. There is a problem that distortion occurs. Conversely, if the content of the matrix material is too large, there is a problem that the number of bonds between the cellulose fibers decreases and the strength of the composite material decreases.

  The content of the cellulose fiber and the matrix material in the composite material can be determined, for example, from the weight of the cellulose fiber membrane before the resin impregnation as the matrix material and the weight of the composite material after the impregnation. Alternatively, the composite material may be immersed in a solvent in which the matrix resin is soluble to remove only the resin, and the composite material may be obtained from the weight of the remaining cellulose fiber membrane. In addition, the functional group of the resin or cellulose can also be determined quantitatively using a method of obtaining from the specific gravity of the resin, NMR, or IR.

[Thickness]
The thickness of the composite material of the present invention is preferably 20 μm or more and 10 mm or less. By using a cellulose fiber composite material having such a thickness, sufficient strength can be obtained. The thickness of the composite material is more preferably 25 μm or more and 8 mm or less, and further preferably 30 μm or more and 5 mm or less.

  Here, the thickness of the cellulose fiber composite material is measured at 3 to 10 points at an arbitrary position of the cellulose fiber composite material using a film thickness meter (“IP65” manufactured by Mitutoyo Corporation), and the average value thereof is calculated. It is the value calculated as thickness.

  The composite material of the present invention is preferably in the form of a film (film) or plate having such a thickness, but is not limited to a flat film or flat plate, and may be a film or plate having a curved surface. . Other irregular shapes may also be used. Further, the thickness is not necessarily uniform, and may be partially different.

[Haze]
The composite material obtained by combining the cellulose fiber membrane of the present invention and the transparent resin can be a material having high transparency, that is, low haze.
The haze value of this composite material is 10% or less as a value measured in accordance with JIS K7136 at any film thickness of 10 to 200 μm. In particular, this value is 5% or less, especially 2 or less, further 1% or less. It is preferable that it is used as various transparent materials.
If the haze of the cellulose fiber composite material is too large, light scattering increases, so that there is a problem that the transmitted light intensity decreases and the contrast decreases.
The haze measurement of the cellulose fiber composite material can be performed using, for example, a Suga Test Instruments haze meter based on JIS K7136, and using the value of C light.

If the haze is large on the substrates of the organic electroluminescence display and the liquid crystal display, the parallel light transmittance is lowered, the contrast ratio is lowered, and the display performance is lowered.
Since the cellulose fiber composite material of the present invention has a small haze, such a problem can be solved.

[Phase difference]
The cellulose fiber composite material of the present invention is characterized in that a phase difference at a thickness of 50 μm is 20 nm or less. This phase difference is preferably 10 nm or less. If the phase difference is too large, there is a problem in that the contrast is lowered and black becomes white.
The retardation of the cellulose fiber composite material is measured by measuring the phase difference at a wavelength of 589 nm by a rotating analyzer method using a RETS-100 type retardation film / optical material evaluation apparatus manufactured by Otsuka Electronics Co., Ltd. Is a value calculated as a phase difference per 50 μm by the following formula.
Phase difference of cellulose fiber composite material =
Measurement value of phase difference × (50 (μm) / thickness of cellulose fiber composite material (μm))

In an organic electroluminescence display, a circularly polarizing plate is bonded to the substrate to prevent reflection, but it is designed so that there is no phase difference of the substrate. There is a problem that garbage will occur. In the liquid crystal display, the brightness is controlled by controlling the deflection angle of the liquid crystal. However, when the phase difference is generated on the substrate, the brightness is shifted and the hue is also shifted.
The cellulose fiber composite material of the present invention can solve such a problem because the phase difference is small.

[Total light transmittance]
The total light transmittance of the cellulose fiber composite material of the present invention is preferably 87% or more, more preferably 89% or more, in any film thickness of 10 μm to 200 μm. When the total light transmittance is low, there is a problem that the cellulose fiber composite material becomes whitish and opaque. In addition, there is a problem that the light transmission efficiency deteriorates when used in optical applications.

  In addition, the total light transmittance of a cellulose fiber composite material is measured by C light using the Suga Test Instruments haze meter based on JISK7105. Here, the total light transmittance is the sum of the parallel light transmittance and the diffuse transmittance.

[Light transmittance]
The cellulose fiber composite material of the present invention preferably has a light transmittance of 85% or more in the entire wavelength region from 400 nm to 800 nm, and has a light transmittance of 86% or more as optical characteristics required for display applications. Is more preferable. When the light transmittance of the cellulose fiber composite material is small, there is a problem that the cellulose fiber composite material becomes whitish and opaque. In addition, there is a problem that the light transmission efficiency deteriorates when used in optical applications.

Further, as optical characteristics required for display applications, it is preferable that the slope of light transmittance is 0.022% / nm or less in the wavelength region of 400 nm to 600 nm, and this slope is further 0.020% / nm or less. It is preferable. When the inclination of the light transmittance is large, there is a problem that the hue balance is deteriorated and coloring occurs.
The slope of light transmittance is the slope of a straight line connecting the light transmittance at a wavelength of 400 nm and the light transmittance at a wavelength of 600 nm in the light transmittance chart with the light transmittance as the vertical axis and the wavelength as the horizontal axis. It is a value obtained by dividing the difference between the light transmittance at 400 nm and the light transmittance at 600 nm by the wavelength bandwidth 200 nm (= 600 nm−400 nm).

[Linear expansion coefficient]
The cellulose fiber composite material of the present invention can be a material having a low linear expansion coefficient by using the cellulose fiber membrane of the present invention.
The linear expansion coefficient of the composite material is preferably 0.5 to 50 ppm / K, more preferably 30 ppm / K or less, and particularly preferably 20 ppm / K or less.

If the linear expansion coefficient of the cellulose fiber composite material is too large, there is a problem that the pattern wiring on the cellulose fiber composite material is disconnected, for example, due to expansion and contraction during the heating process of the composite material. If the linear expansion coefficient is too small, there is a problem that a difference in linear expansion coefficient from the material laminated on the composite material becomes large and peeling occurs.
The linear expansion coefficient is measured by SII TMA120.

When the linear expansion coefficient is large in the substrate of the organic electroluminescence display and the liquid crystal display, problems such as disconnection occur at the time of heating required in the manufacturing process.
Since the cellulose fiber composite material of the present invention has a low linear expansion coefficient, such a problem can be solved.

[4] Use of Cellulose Fiber Composite Material The cellulose fiber composite material of the present invention has a low linear expansion coefficient due to the stretch chain crystal of cellulose, and exhibits high elasticity and high strength. In addition, by refining cellulose fibers and suppressing orientation, a composite material having high transparency, low coloring and haze, and low optical retardation and high optical isotropy when combined with a transparent resin is obtained. be able to.
Thus, since it is excellent in optical characteristics, the composite material of the present invention is suitable for displays, substrates and panels of liquid crystal displays, plasma displays, organic EL displays, field emission displays, rear projection televisions and the like. In these applications, glass can be substituted as a flexible material, and an improvement effect such as weight reduction, flexibility, formability, and designability can be obtained.
In addition, the cellulose fiber composite material of the present invention can be used as a structural material for purposes other than the use of transparent materials by taking advantage of characteristics such as a low coefficient of linear expansion, high elasticity, and high strength. In particular, automotive materials such as glazing, interior materials, outer plates, and bumpers, personal computer casings, home appliance parts, packaging materials, building materials, civil engineering materials, marine products, and other industrial materials are preferably used.

  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.

  In the following, physical properties or characteristics of the produced cellulose fibers, cellulose fiber membranes, and cellulose fiber composite materials were evaluated by the following methods.

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

<Thickness of cellulose fiber composite material>
Using a film thickness meter (“IP65” manufactured by Mitutoyo Corporation), 3 to 10 points were measured at any position of the cellulose fiber composite material, and the average value was taken as the thickness.

<Cellulose fiber content of cellulose fiber composite material>
It calculated | required from the weight of the used cellulose fiber membrane (or bacterial cellulose membrane) and the weight of the obtained cellulose fiber composite material.

<Phase difference of cellulose fiber composite material>
The phase difference at a wavelength of 589 nm was measured by a rotary analyzer method using a RETS-100 type retardation film / optical material evaluation apparatus manufactured by Otsuka Electronics Co., Ltd., and the phase difference per 50 μm was calculated from the thickness obtained by the above thickness measurement. .

<Haze of cellulose fiber composite material>
Based on JIS K7136, the haze value by C light was measured using the haze meter by Suga Test Instruments.

<Total light transmittance of cellulose fiber composite material>
Based on JIS K7105, the total light transmittance by C light was measured using the haze meter by Suga Test Instruments.

<Light transmittance of cellulose fiber composite material>
The light transmittance was measured in a wavelength range of 200 nm to 800 nm using a spectrophotometer U-4000 manufactured by Hitachi, Ltd.
In the measurement of the light transmittance, the difference between the light transmittances of 400 nm and 600 nm was obtained, and this was divided by the wavelength bandwidth of 200 nm to obtain the slope of the light transmittance.
Further, the minimum light transmittance in the wavelength band of 400 to 800 nm was obtained.

<Linear expansion coefficient of cellulose fiber composite material>
The obtained composite material was cut into 3 mm width × 40 mm length with a laser cutter. This was carried out in a tensile mode using TMA120 manufactured by SII at a rate of 5 ° C./min. From room temperature to 180 ° C. in a nitrogen atmosphere of 20 mm between chucks and a load of 10 g. At 180 ° C. to 25 ° C. at 5 ° C./min. At 25 ° C to 180 ° C, 5 ° C / min. The linear expansion coefficient was determined from the measured value from 60 ° C. to 100 ° C. during the second temperature increase.

<Refractive index of resin>
A cured resin having a thickness of 1 mm is cut into a 20 mm × 20 mm square, and the cut end is polished with a polisher or the like, and then a refractive index at a wavelength of 587.6 nm is set to a sample temperature of 25 ° C. using Kalnew KPR-2000 manufactured by Shimadzu Corporation. Measured at ± 0.1 ° C.

[Production Example 1: Production of Cellulose Fiber Dispersion 1]
Rice pine wood flour (Miyashita Wood Co., Ltd.) was degreased with a 2% by weight aqueous solution of sodium carbonate at 80 ° C. for 6 hours. After washing this with demineralized water, an aqueous solution adjusted to 0.66% by weight sodium chlorite and 0.14% by weight acetic acid was added and immersed for 5 hours at 80 ° C. to remove lignin. Next, after washing with demineralized water, filtration was performed, the recovered purified cellulose was washed with demineralized water, and then immersed in a 5 wt% aqueous potassium hydroxide solution for 16 hours to remove hemicellulose. Further, after washing with demineralized water, a 0.5% by weight aqueous suspension of the cellulose fiber raw material is formed, and this aqueous suspension is used as an ultra-high pressure homogenizer (Ultimizer “single nozzle type / pore diameter 150 μm”, manufactured by Sugino Machine Co., Ltd. Was used, pressure was applied to 245 MPa, ejection was performed under normal pressure, and a cellulose fiber dispersion 1 was obtained by treatment with 10 passes.

[Production Example 2: Production of Cellulose Fiber Dispersion 2]
Cellulose fiber dispersion 2 was obtained in the same manner as in Production Example 1, except that the number of passes of an aqueous suspension of 0.5% by weight of the cellulose fiber raw material was 30 times using an ultrahigh pressure homogenizer.

[Production Example 3: Production of Cellulose Fiber Dispersion 3]
A 0.5% by weight aqueous suspension of the cellulose fiber raw material produced in the same manner as in Production Example 1 was treated with an ultrahigh pressure homogenizer in the same manner as in Production Example 1 except that the number of passes was 5, and then Using an ultrasonic homogenizer UH600S (20 kHz) manufactured by SMT, treatment was performed for 60 minutes (50% intermittent operation) with a power scale 8. When the output at this time was measured from the temperature rise of water, it was 224W. Then, it processed for 30 minutes at 18,000 rpm using Hitachi Koki centrifuge CR-22G, the supernatant was taken out, and this was made into the cellulose fiber dispersion 3.

[Production Example 4: Production of Cellulose Fiber Dispersion 4]
1 liter of a 0.5% by weight aqueous suspension of cellulose fiber raw material produced in the same manner as in Production Example 1 was put into a stone mill grinder “Supermass colloider MKCA6-2” manufactured by Masuko Sangyo Co., Ltd. Using a GC6-80 stone mortar, the gap was set to 80 μm, and grinding was performed at a rotational speed of 1500 rpm. The treated cellulose fiber dispersion that passed through the grinder was again charged into the raw material inlet, and the cellulose fiber dispersion 4 was obtained by passing through the grinder a total of 10 times.

[Production Example 5: Production of bacterial cellulose film]
A culture solution was added to a strain of acetic acid bacteria in a freeze-dried storage state, and the mixture was allowed to stand for 1 week (25 to 30 ° C.). Among the bacterial celluloses produced on the surface of the culture solution, those having a relatively large thickness were selected, and a small amount of the culture solution of the strain was taken and added to a new culture solution. And this culture solution was put into the large incubator, and the static culture was performed at 25-30 degreeC for 30 days. In the culture solution, glucose 2% by weight, Bacto yeast extra 0.5% by weight, Bacto peptone 0.5% by weight, Disodium hydrogen phosphate 0.27% by weight, Citric acid 0.115% by weight, Magnesium sulfate hemihydrate An aqueous solution (SH medium) adjusted to pH 5.0 with hydrochloric acid was used, which was 0.1% by weight of the Japanese product.

  The bacterial cellulose thus produced is taken out from the culture solution and boiled in a 2% by weight aqueous alkali solution for 2 hours. Thereafter, the bacterial cellulose is taken out from the alkaline treatment solution and washed thoroughly with water to remove the alkaline treatment solution. Bacteria in the bacterial cellulose were dissolved and removed to obtain hydrous bacterial cellulose having a thickness of 1 cm, a fiber content of 1% by volume, and a water content of 99% by volume. This hydrous bacterial cellulose is immersed in 2-propanol, press-molded and dried at 120 ° C. and 2 MPa for 5 minutes, further immersed in water and ethanol, and then reheated and pressed at 120 ° C. and 2 MPa for 5 minutes to obtain a thickness of 50 μm, A bacterial cellulose membrane having a porosity of 48.0 vol% was obtained. The pressure applied to the press is a gauge reading, and the heating press used is a small heating press (10t) 180C manufactured by Imoto Seisakusho.

[Production Example 6: Production of cotton linter cellulose fiber dispersion]
Except that cotton linter was used instead of rice pine wood flour, degreasing, lignin removal, and hemicellulose removal were carried out in the same manner as in Production Example 1, followed by washing with demineralized water to obtain a 0.5% by weight aqueous suspension. . One liter of this water suspension was triturated 10 times in the same manner as in Production Example 4 to obtain a cotton linter cellulose fiber dispersion.

[Example 1]
The cellulose fiber dispersion 1 produced in Production Example 1 was diluted with water to a cellulose fiber concentration of 0.13% by weight and sufficiently stirred, and 150 g of that was filtered by Advantech filtration filter T100A090C (air when a pressure difference of 200 kPa was applied) Advantech vacuum filtration system appliance KG- in which the permeability is 18100 cm ³ · cm ^-2 · min ^-1 , and extrapolated to 4.6 cm ³ · cm ^-2 · min ^{-1 at} 124.5 Pa horizontally Suction filtration was performed using 90. The degree of vacuum during suction filtration was about -90 kPa, and about 30 ml of isopropyl alcohol (IPA) was added to the end of the filtration for filtration. After filtration, a hot press was performed at 120 ° C., 2 MPa, and 5 minutes. The pressure applied to the press is a gauge reading, and the heating press used is a small heating press (10t) 180C manufactured by Imoto Seisakusho. The heating press is a PTFE (polytetrafluoroethylene) with a thickness of 1 mm, which is covered with a PET (polyethylene terephthalate) mesh (opening 1 μm) with a wet membrane made of cellulose fibers remaining with a large amount of solvent remaining after filtration. It was sandwiched between SUS plates having a thickness of 10 mm that had been heated at 120 ° C., and the cellulose fiber membrane was molded and dried. After the heat pressing, only the cellulose fiber membrane was taken out.

A cellulose fiber composite material was produced by the following method using the obtained cellulose fiber membrane.
As a matrix material, 94 parts by weight of bis (methacryloyloxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane, ⁶ parts by weight of pentaerythritol tetrakisthio (β-propionate), 2,4,6-trimethylbenzoyldiphenylphos A cellulose fiber membrane was impregnated with a solution obtained by mixing 0.05 parts by weight of fin oxide (BASC's Lucillin TPO) and 0.05 parts by weight of benzophenone. This was sandwiched between two glass plates, and using an electrodeless mercury lamp (“D bulb” manufactured by Fusion UV Systems) with an output of 184 W / cm, the irradiated glass surface irradiated light amount of 300 mW / cm ² and 0. Ultraviolet rays were irradiated at 23 ° C. for 2 seconds. The temperature of the glass surface after ultraviolet irradiation was 25 ° C. Next, in order to irradiate the glass surface on the opposite side with ultraviolet rays, the sample was turned upside down and irradiated with ultraviolet rays under the same conditions as before, and then the irradiated glass surface was irradiated with an irradiation light amount of 1800 mW / cm ² at 2 Irradiated with UV light for 2 seconds. The temperature of the glass surface after ultraviolet irradiation was 40 ° C. After the ultraviolet irradiation was completed, the cellulose fiber composite material was obtained by removing from the glass plate. The ultraviolet illuminance was measured with an ultraviolet illuminance meter “UV-M02” manufactured by Oak Manufacturing Co., Ltd., and the illuminance of ultraviolet rays of 320 to 390 nm was measured at 23 ° C. using an attachment “UV-35”.

  In addition, the refractive index of resin as a matrix material which comprises this cellulose fiber composite material is 1.53.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

[Example 2]
Cellulose fiber membrane was prepared by diluting, filtering and heating the cellulose fiber dispersion in the same manner as in Example 1 except that the cellulose fiber dispersion 2 produced in Production Example 2 was used instead of the cellulose fiber dispersion 1. In the same manner, a cellulose fiber composite material was produced.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

[Example 3]
Cellulose fiber membrane was prepared by diluting, filtering and heating the cellulose fiber dispersion in the same manner as in Example 1 except that the cellulose fiber dispersion 3 produced in Production Example 3 was used instead of the cellulose fiber dispersion 1. In the same manner, a cellulose fiber composite material was produced.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

[Comparative Example 1]
Cellulose fiber membrane was prepared by diluting, filtering and heating the cellulose fiber dispersion in the same manner as in Example 1 except that the cellulose fiber dispersion 4 produced in Production Example 4 was used instead of the cellulose fiber dispersion 1. In the same manner, a cellulose fiber composite material was produced.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

[Comparative Example 2]
A cellulose fiber composite material was produced in the same manner as in Example 1 using the bacterial cellulose membrane produced in Production Example 5 instead of the cellulose fiber membrane produced from Cellulose Fiber Dispersion Liquid 1.

  The evaluation results of the bacterial cellulose membrane and the cellulose fiber composite material are shown in Table 1.

[Comparative Example 3]
The cotton linter cellulose fiber dispersion was diluted, filtered and heated in the same manner as in Example 1 except that the cotton linter cellulose fiber dispersion produced in Production Example 6 was used instead of the cellulose fiber dispersion 1. A cellulose fiber membrane was obtained, and a cellulose fiber composite material was produced in the same manner.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

[Comparative Example 4]
Without diluting the cellulose fiber dispersion produced in Production Example 1, 44.2 g of the cellulose fiber dispersion was subjected to suction filtration using an Advantech vacuum filtration system tool KG-90 in which Advantech filtration filter T100A090C was set. The solid content concentration (cellulose fiber concentration) of the cellulose fiber dispersion at this time was 0.587% by weight. The degree of vacuum during suction filtration was about -90 kPa, and about 30 ml of IPA was added to the end of filtration. After filtration, a hot press was performed at 120 ° C., 2 MPa, and 5 minutes. The pressure applied to the press is a gauge reading, and the heating press used is a small heating press (10t) 180C manufactured by Imoto Seisakusho. A wet membrane made of cellulose fibers in which a large amount of solvent remained after filtration was covered with a PET mesh (aperture 1 μm) while placed on the filtration filter, sandwiched between PTFE plates having a thickness of 1 mm, and further heated at 120 ° C. The cellulose fiber membrane was molded and dried by heating and pressing with a 10 mm thick SUS plate. After the heat pressing, only the cellulose fiber membrane was taken out.

  A cellulose fiber composite material was produced in the same manner as in Example 1 except that this cellulose fiber membrane was used as the cellulose fiber membrane.

  Table 1 shows the evaluation results of the cellulose fiber membrane and the cellulose fiber composite material.

  From Table 1, it can be seen that according to the present invention, a cellulose fiber composite material having high transparency, low retardation, low haze, optical isotropy, transparency and other optical properties is provided.

Claims (6)

  A cellulose fiber composite material comprising cellulose fibers and a matrix material, wherein the cellulose fiber content is 40% by weight or more, the phase difference at a thickness of 50 μm is 20 nm or less, and the film thickness is 10 μm or more and 200 μm or less according to JIS K7136. A cellulose fiber composite material having a haze of 5% or less.   2. The cellulose fiber composite material according to claim 1, wherein the refractive index of the matrix material with respect to light having a wavelength of 587.6 nm is 1.45 to 1.65 at 25 ° C. 3.   3. The cellulose fiber membrane produced by filtering a cellulose fiber dispersion having a cellulose fiber content of 0.01 to 0.2% by weight is formed by combining with a matrix material. Cellulose fiber composite material.   The cellulose fiber composite according to any one of claims 1 to 3, wherein the cellulose fiber raw material liquid is defibrated (miniaturized) by jetting from a high-pressure atmosphere of 100 MPa or more and decompressed, and then filtered. material.   The cellulose fiber composite material according to any one of claims 1 to 4, wherein the total light transmittance according to JIS K7105 is 87% or more at any thickness of 10 µm to 200 µm.   The light transmittance in the entire range of wavelengths from 400 to 800 nm is 85% or more, and the slope of the light transmittance in the range of wavelengths from 400 nm to 600 nm is 0.022 (% / nm) or less. The cellulose fiber composite material according to any one of 5.