JP7238002B2 - CNF molding device and CNF molding method - Google Patents

Description

The present invention relates to a CNF molding method.

Cellulose is naturally found in fibrous form in plants such as woody plants such as broadleaf trees and conifers, herbaceous plants such as bamboo and reeds, some animals such as sea squirts, and some acetic acid bacteria. is known to be produced by fungi and the like. A structure in which cellulose molecules are aggregated in a fibrous form is called a cellulose fiber. In particular, cellulose fibers with a fiber width of 100 nm or less and an aspect ratio of 100 or more are generally called cellulose nanofibers (CNF), and have excellent properties such as light weight, high strength, and low coefficient of thermal expansion.

In nature, CNF does not exist as single filaments, except for CNF produced by some fungi such as acetic acid bacteria. Most of the CNFs exist in a state of having micro-sized fiber widths tightly aggregated by interactions represented by hydrogen bonds between CNFs. Fibers with the micro-sized fiber width also exist as higher-order aggregates.

In the papermaking process, wood, which is an aggregate of these fibers, is fibrillated to a state of pulp with micro-sized fiber width by a pulping method represented by the Kraft cooking method, which is one of the chemical pulping methods. , which is used to manufacture paper. The fiber width of this pulp varies depending on the raw material, but is 5-30 μm for bleached kraft pulp made from hardwood, 20-100 μm for bleached kraft pulp made from softwood, and 5-30 μm for bleached kraft pulp made from bamboo. degree.

As mentioned above, these micro-sized fiber width pulps are aggregates of single fibers having a fibrous form in which CNFs are strongly aggregated by interactions represented by hydrogen bonds. CNFs with nano-sized fiber widths can be obtained.

Many CNF preparation methods have been reported, but they are roughly divided into two types: chemical methods such as acid hydrolysis and TEMPO catalytic oxidation, and physical methods such as grinder method, high-pressure homogenizer method, and underwater counter-impingement method. . Whichever method is used, CNF is basically obtained in a water-dispersed state.

The following patent documents have been published for a molding method for a slurry containing CNF and a method for producing a molded body.

Patent Document 1 describes a step of contacting a surface of a porous substrate with a liquid containing one or more solvents and one or more polymers, and removing the solvent by the porous substrate and reducing the solid content of the liquid. is 4% or more to form a molded article. The polymer used is a fibrous polymer having a short axis direction of 1 nm or more and 500 nm or less and a long axis direction of 500 nm or more and 1000 μm or less. Disclosed is a method for manufacturing a molded product.

In addition, Patent Document 2 discloses cellulose nanoparticles having an average fiber diameter of 10 to 100 nm and an average aspect ratio of 1000 or more to solve the problem of providing a high-strength and lightweight material that does not generate combustion residue at the time of disposal. A high-strength material having a density of 1.2 g/cm3 or more and 1.4 g/cm3 or less, a bending strength of 200 MPa or more, and a bending elastic modulus of 14 GPa or more by pressing the fiber at high temperature and high pressure. disclosed.

JP 2011-038031 JP 2013-11026

However, since the CNF molded body obtained by the CNF molding method disclosed in these patent documents is about 2 mm at most, it is not possible to obtain any shaped object by cutting the molded body, for example. As described above, CNF is dispersed in water, and the CNF content in the dispersion is about 0.1 to 10%, so it has a thickness that allows cutting, and the inside is When trying to obtain a uniform CNF molded body, the amount of solvent in the CNF dispersion liquid inevitably increases. Therefore, there is more time to remove the solvent from the CNF dispersion. If a long time is required, even if a CNF molded article can be produced, a CNF layer or cavities will occur inside the molded article, making it impossible to obtain a uniform molded article.

In view of the above problems in the prior art, the present invention is a CNF that can reduce the time required for solvent removal, has a thickness that allows cutting, and can obtain a molded body with a uniform interior. An object of the present invention is to provide a molding apparatus and a CNF molding method.

A first aspect of the present invention is a CNF molding apparatus that applies a load to a slurry containing cellulose nanofibers (hereinafter referred to as CNF) using a vapor permeation means that allows vapor to permeate, wherein a molding cavity is defined by a main body and a bottom plate. A molding die for forming is provided, CNF input means for the molding cavity is provided, the bottom plate can be fitted inside the main body, and pressurizing means for pressing the main body in the direction of the bottom plate. Characterized by

A second aspect of the present invention is a CNF molding method that applies a load using a vapor permeation means that allows vapor to permeate a CNF-containing slurry, comprising a molding die that forms a molding cavity with a main body and a bottom plate, wherein the molding It is characterized by providing CNF injection means for the cavity, the bottom plate being able to be fitted inside the main body, and having a step of pressing the main body in the direction of the bottom plate.

ADVANTAGE OF THE INVENTION According to this invention, the time which a solvent removal requires is reduced, and it has thickness which can be cut, and can obtain the CNF molded object with a uniform inside.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram of the CNF shaping|molding apparatus of one embodiment of this invention. 1 is a photograph of a molded body obtained by a CNF molding apparatus according to one embodiment of the present invention; FIG. 3 is a photograph of a product obtained by cutting from the molded body shown in FIG. 2. FIG. 3 is another photograph of a product obtained by cutting from the molded body shown in FIG. 2. FIG. FIG. 6 is a graphical representation of the flexural strength data shown in Table 6. FIG. 8 is a graphical representation of the flexural modulus data shown in Table 8. FIG. 9 is a graphical depiction of the contact angle data presented in Table 9. FIG.

As shown in FIG. 1, a CNF forming apparatus 1 of this embodiment has a main body 2 and a bottom plate 3 which are supported in a movable state and which use vapor permeation means. The bottom plate 3 is held in a non-movable state. A molding cavity 4 is formed by the body portion 2 and the bottom plate 3 . Further, the body portion 2 is composed of a mold portion 2a, a mold portion 2a using vapor permeation means, and an upper plate 2b, and the upper plate 2b is arranged on the opposite side of the bottom plate 3 via the mold portion 2a. be. A hydraulic actuator 5, which is pressurizing means, is attached to the upper plate 2b, and by applying a load to the hydraulic actuator 5, the upper die 2b can press the die portion 2a toward the bottom plate 3. As shown in FIG. Further, the upper mold 2b is equipped with a nozzle 6, which is a means for introducing CNF into the molding cavity 4.

A far infrared ray generator 7, which is a heating means for heating the mold portion 2a, is arranged near the mold portion 2a. A band heater or the like can also be used as other heating means.
In the CNF molding apparatus 1 of the present embodiment as described above, the inner diameter of the mold portion 2a and the outer diameter of the bottom plate 3 are substantially matched, so that the bottom plate 3 can be fitted inside the mold portion 2a. .
On the other hand, the outer diameter of the upper die 2b and the outer diameter of the die portion 2a are made substantially equal to each other. The movement is transmitted to the portion 2a, and the entire body portion 2 supported in a movable state moves toward the bottom plate 3. As shown in FIG.
On the other hand, the bottom plate 3, which is held in a non-movable state, is held at a fixed position. As a result, when the entire body portion 2 moves toward the bottom plate 3, the bottom plate 3 is fitted inside the mold portion 2a, and the volume of the molding cavity 4 is reduced. do.

As the vapor permeation means, for example, a porous body using a porous material can be used. As the porous material, various materials such as organic, inorganic, metal, or composite thereof, specifically stainless steel, SiC, ceramic, resin, rubber, glass, paper, etc. can be used. . Moreover, you may use these in combination as needed. As for the average pore diameter and porosity of the porous body to be used, those having an average pore diameter of 5 to 200 μm and a porosity of 30 to 85% can be used, preferably an average pore diameter of 5 to 60 μm and a porosity of 30 to 85%. 40 to 70% should be used.
The porosity is (1) the sum of the volume of pores communicating with the outside and the volume of pores enclosed inside, divided by the total volume (apparent volume), and (2) the volume of pores communicating with the outside. There are two types of pore volume divided by the total volume, and either calculation method can be used in the present invention.

A possible method of improving permeation is concentration using an object that is permeable to vapor. Objects that allow vapor to permeate include textiles, felt, various filters such as membrane filters and sintered filters, filter paper, substances with permeation mechanisms such as holes, stacks of plates and bars, porous and fine-grained substances. Aggregates (sand, silica, or other fine particles forming a pseudo-porous structure) are also possible. In addition, water can be easily dehydrated by using a hydrophilic base material. Furthermore, if the permeation mechanism is 1 μm or less, the outflow of CNF can be prevented. Furthermore, these single use or combination use is considered. Moreover, there are no restrictions on the load and the direction of steam permeation. Moreover, it is possible to allow vapor to permeate under vacuum conditions or reduced pressure conditions, and the means is not particularly limited.

By providing a nozzle 6, which is a CNF injection means into the molding cavity 4, the volume of the molded body to be obtained can be adjusted. Without this nozzle, the size of the resulting molded body is extremely small compared to the size of the molding cavity in the mold part, but by adding the CNF-containing slurry from the nozzle , the mold shape can be maintained.

A CNF molding process performed using the CNF molding apparatus 1 of the present embodiment will be described.
First, in a state where the molding cavity 4 is formed by the bottom plate 3 and the main body portion 2, the CNF-containing slurry is introduced into the molding cavity 4 from the nozzle 6 attached to the upper plate 2b. Around this time, the heating of the mold portion 2a by the far infrared ray generator 7 is started.
When the upper plate 2b is pressurized toward the bottom plate 3 by the hydraulic actuator 5 while a certain amount of CNF is stored in the molding cavity 4, the entire body portion 2 supported in a movable state moves toward the bottom plate 3, and the bottom plate moves toward the bottom plate 3. 3 is fitted inside the mold part 2a, and the volume of the molding cavity 4 is reduced. In the process, the CNF inside the heated mold part 2a shrinks while discharging steam to the outside through the upper plate 2b made of a porous body, and is predetermined according to the shape of the molding cavity 4. It is possible to obtain a required molded body 8 by molding into a shape. In this case, by replenishing CNF from the nozzle 6 during the molding process, a CNF molded body 8 having a required volume can be obtained.
Further, in the above case, if the upper plate 2b and the bottom plate 3 are heated in advance by the far-infrared ray generator 7, the time can be shortened.

[CNF-containing slurry]
In the present invention, CNF includes, for example, CNF derived from polysaccharides including natural plants such as wood fiber, bamboo fiber, sugarcane fiber, seed hair fiber, leaf fiber, and these CNF are one kind alone or two or more kinds. may be mixed and used.
The CNFs used in the present invention have an average thickness of 3 to 200 nm and an average length of 0.1 μm or more, and can be prepared, for example, by fibrillating polysaccharides with a high-pressure water stream. Defibrillation of polysaccharides by high-pressure water jets is carried out by colliding high-pressure water of about 50-400 MPa against polysaccharides made into a water mixture of 0.5-10% by mass. For the measurement of the average thickness and average fiber length, a scanning electron microscope (SEM), a transmission electron microscope (TEM), etc. are appropriately selected, CNF is observed and measured, and 20 or more are selected from the obtained photographs. , are obtained by averaging them respectively. However, the method for preparing CNF used in the present invention is not limited to this, and it can also be prepared by chemical methods such as acid hydrolysis method and TEMPO catalytic oxidation method, and physical methods such as grinder method and high pressure homogenizer method. .

In the present invention, a CNF-containing slurry is obtained by adding a metal salt, pulp made from hardwood, softwood or bamboo, or a cross-linking agent to a CNF aqueous dispersion. Furthermore, the thing which replaced the water solvent with the organic solvent can also be used as a CNF containing slurry.

On the other hand, CNF is generally known to have many hydroxyl groups in its molecule and to be extremely hydrophilic. Therefore, when a CNF molded body is produced while still having a large number of hydroxyl groups in its molecule, the hydrophilicity and water absorption of the CNF molded body itself may become a problem. In other words, it may be required that the CNF molded article can be used even in situations where water resistance is required.

Therefore, in order to solve this problem, it is possible to use hydrophobic CNFs in which some of the functional groups are modified to vinyl esters or organic acid vinyl esters. Examples of vinyl esters or organic acid vinyl esters include linear or branched C2 esters such as vinyl acetate, vinyl butyrate, vinyl stearate, vinyl laurate, vinyl myristate, vinyl propionate, and vinyl versatic acid. Vinyl esters of -20 aliphatic carboxylic acids and aromatic carboxylic acids such as vinyl benzoate can be exemplified. By using CNF having such hydrophobicity, a hydrophobic CNF molded article can be produced.

Then, the CNF concentration in the CNF-containing slurry should be in the range of 2% to 10%. If it is 2% or less, the amount of solvent is large and dehydration takes time. Moreover, if it is 10% or more, the inside of the CNF molded body becomes hollow. Furthermore, the temperature of the CNF-containing slurry may be adjusted to a range of 20 to 95°C, preferably 40 to 80°C, using the heating means. At a liquid temperature of 20°C or less, dehydration takes time. In addition, if the temperature is higher than the boiling point of the solvent, the solvent will be in a boiling state, causing traces of air bubbles in the molded article, making it impossible to obtain a uniform molded article.

[Metal salt]
The metal salt to be added to the CNF aqueous dispersion is preferably one or more compounds selected from the group consisting of, for example, inorganic phosphorus compounds, metal salts of phosphorous acid or hypophosphorous acid. By adding a metal salt to form light aggregates of CNF, the time for dehydrating the solvent can be reduced.
Examples of inorganic phosphorus compounds include phosphoric acid-based compounds, phosphorous acid-based compounds, and hypophosphorous acid-based compounds. Specific examples of such phosphoric acid compounds include phosphoric acid, diphosphate, triphosphate, lithium phosphate, beryllium phosphate, sodium phosphate, magnesium phosphate, aluminum phosphate, potassium phosphate, and calcium phosphate. Specific examples of phosphorous acid compounds include phosphorous acid, lithium phosphite, beryllium phosphite, sodium phosphite, magnesium phosphite, aluminum phosphite, potassium phosphite, calcium phosphite, and the like. Specific examples of hypophosphite compounds include hypophosphorous acid, lithium hypophosphite, beryllium hypophosphite, sodium hypophosphite, magnesium hypophosphite, aluminum hypophosphite, Potassium phosphite, calcium hypophosphite and the like.
In addition, for example, hydroxides such as potassium hydroxide, sodium hydroxide, barium hydroxide, lithium hydroxide; zinc chloride, aluminum chloride, calcium chloride, strontium chloride, ferric chloride, tertiary chloride Chlorides such as cupric chloride, barium chloride, manganic chloride, tertiary manganese chloride, quaternary manganese chloride, sodium chloride, potassium chloride; zinc chloride, aluminum sulfate, potassium sulfate, zirconium sulfate, copper sulfate, sulfuric acid Sulfates such as sodium, magnesium sulfate and manganese sulfate; nitrates such as zinc nitrate, aluminum nitrate, potassium nitrate, calcium nitrate, strontium nitrate, copper nitrate, sodium nitrate, barium nitrate, magnesium nitrate and manganese nitrate; zinc acetate, potassium acetate, Acetates such as calcium acetate, strontium acetate, sodium acetate, barium acetate, magnesium acetate;
Among these compounds, more preferred are divalent metal ions such as magnesium and calcium, or trivalent metal ions such as aluminum.
Also, the amount to be added is 1% or more, more preferably in the range of 5% to 10%, relative to the resulting CNF molded product. If it is added in an amount of 10% or more, the strength of the CNF molded body may decrease.

[pulp]
The pulp to be added to the CNF aqueous dispersion can be any one of pulp made from broad-leaved trees, pulp made from coniferous trees, and pulp made from bamboo, or a combination thereof. Moreover, it is preferable to appropriately select and use pulp fibers having a fiber length of 0.5 to 5.0 mm and a pulp fiber length of 10 to 100 μm. Furthermore, the amount of addition should be in the range of 10 to 30% with respect to the CNF molded product obtained. At this time, if the amount of pulp added is 10% or less, the time required for filtration will not be shortened, and if the amount of pulp added is 30% or more, even if it is added more than this, the filtration time will not be shortened. This is because it has little effect on shortening.

[Crosslinking agent]
As a cross-linking agent, the hydroxyl groups possessed by cellulose nanofibers or modified cellulose nanofibers, and functional groups in which the hydroxyl groups are modified to have other functional groups such as carboxyl groups, phosphoric acid groups, amino groups, etc. are reactive. For example, isocyanate-based cross-linking agents, epoxy-based cross-linking agents, amine-based cross-linking agents, melamine-based cross-linking agents, aziridine-based cross-linking agents, hydrazine-based cross-linking agents, aldehyde-based cross-linking agents, oxazoline-based cross-linking agents, metal alkoxides cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, ammonium salt-based cross-linking agents, and the like. Furthermore, these polymerization initiators can also be used together. Among them, an isocyanate-based cross-linking agent has an advantage of being excellent in reactivity with the hydroxyl group. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types. The cross-linking agent can be used for the purpose of improving physical properties such as bending strength and bending elastic modulus of the CNF molded article, or for the purpose of adding other functions to the CNF molded article.

The content of the additive is preferably 1% to 10% relative to the solid content of cellulose nanofibers. At 1% or less, the cross-linking agent and cellulose nanofibers may not react, and at 10% or more, the cross-linking agent is too excessive and the characteristics of the cellulose nanofibers may be reduced.

As the isocyanate-based cross-linking agent, a polyfunctional isocyanate (meaning a compound having an average of two or more isocyanate groups per molecule, including those having an isocyanurate structure) can be preferably used. For example, isocyanate acrylate or tolylene diisocyanate, diphenylmethane diisocyanate, aromatic polyisocyanates such as xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, and the like, and biuret, isocyanurate, and adducts which are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. The isocyanate-based cross-linking agents may be used singly or in combination of two or more.

[Solvent replacement]
The CNF-containing slurry may be obtained by replacing the solvent of the CNF-containing slurry from the water solvent with an organic solvent. Organic solvents can be used without particular limitation, and examples include alcohols, saturated aliphatic hydrocarbons, esters, ethers, nitriles, aprotic polar solvents, ketones, amides, aromatic hydrocarbons, Hydrogen, nitrogen-containing aromatic compounds, ionic liquids and water are preferred. Examples include hexane, toluene, chloroform, dichloromethane, diethyl ether, THF, ethyl acetate, acetone, acetonitrile, DMF, DMSO, ethanol, methanol, acetic acid, and methyl methacrylate. By using a volatile solvent, the time required for dehydration can be reduced, and the CNF aggregates to improve dehydration.

As an example of the solvent replacement treatment method, methanol replacement treatment is given. First, CNF and water contained in the CNF and the same amount of methanol are mixed and stirred, and then the mixed and stirred liquid is vacuum filtered. This removes moisture. An appropriate amount of methanol is further supplied to the CNF obtained by this removal, and the CNF is evenly dispersed in the methanol liquid. Although the case where methanol is used as the replacement medium is exemplified here, it is also possible to perform the replacement treatment using a solvent other than methanol.

Of course, the method of solvent replacement is not limited to the above, and other methods can also be adopted. For example, the CNF-containing slurry may be subjected to a freeze-drying process to remove water in the CNF-containing slurry.

EXAMPLES Next, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. Unless otherwise specified, in the present invention, % and the like are based on weight, and the numerical range includes the endpoints.

Example 1
(Liquid temperature and drainage amount of CNF-containing slurry)
Add pure water to 1.816% CNF aqueous dispersion (BB 5pass product) to dilute to 0.1% concentration, and use a water bath to add 0.1% CNF aqueous solution at 12, 27.5, 50, and 80°C. The drainage rate was measured by setting the temperature.
Here, the amount of filtered water refers to the amount of dehydrated water at each time such as 10, 20, 30 minutes after suction-filtrating 200 ml of a 0.1% dispersion of CNF. That is, the larger the amount of filtered water, the better the dehydration property, and the less time it takes to dehydrate the solvent.

Table 1 shows the results. As is clear from Table 1, the amount of filtered water increases as the liquid temperature rises. Therefore, by heating the CNF-containing slurry, the time to dehydrate the solvent can be shortened. Therefore, by heating the mold part of the CNF molding apparatus in the present invention, the time required for solvent removal can be shortened.

Example 2
(Filtration amount of CNF-containing slurry with added metal salt)
Pure water is added to CNF 1.816% aqueous dispersion (BB-5pass product) to dilute it to a concentration of 0.1%, and tricalcium phosphate is added at a ratio of 0, 1, 3, 5, and 10%, At room temperature, the drainage amount was measured for each CNF-containing slurry.

Table 2 shows the results. As is clear from Table 2, the amount of filtered water increases at 5% rather than at 3%. Therefore, adding tricalcium phosphate in an amount greater than 3% can reduce the time required for solvent removal.

Example 3
Using a CNF 1.817% aqueous dispersion (BB-5 pass product), the pulp that has been previously dispersed in water is blended so that the pulp has a predetermined blending ratio, and 0.1% concentration of CNF, pulp The drainage rate of the aqueous dispersion was measured. The temperature was room temperature.

Table 3 shows the results. As is clear from Table 3, when the pulp content was 10%, the amount of drainage increased. It was also found that when the content is in the range of 30% or more, the amount of filtered water does not increase even if the amount of pulp is increased. Therefore, a CNF-containing slurry with a pulp content of 10 to 30% can shorten the time required for solvent removal.

Example 4
(Filtrate amount of CNF-containing slurry replaced with organic solvent)
10% tricalcium phosphate was added to a CNF 2% aqueous dispersion, and suction filtration was performed twice with methanol to obtain 2.5% methanol-wet CNF. This was used as a 0.1% CNF methanol solution and referred to as Example 4. Comparative Example 2 was prepared by adding 10% tricalcium phosphate to a 2% CNF aqueous dispersion and diluting the mixture to 0.1%.
Sedimentation velocity was measured using these drainage amount and solution stability evaluation equipment (Eiko Seiki Co., Ltd.).

Table 4 shows the drainage amount results, and Table 5 shows the sedimentation velocity measurement results. As is clear from Table 4, the example in which the solvent was replaced with methanol was able to filter 200 ml in 1 minute. Moreover, from Table 5, it can be seen that Example 4, in which the solvent was replaced with methanol, had a faster sedimentation rate. Therefore, the CNF-containing slurry substituted with the organic solvent can shorten the time required for solvent removal.

Example 5
(Creation of CNF molded body using CNF-containing slurry of water solvent and cutting using it)
7.91 kg of 2% CNF aqueous dispersion (158 g of CNF), 135.8 g (67.8 g) of 50% pulp product and 11 g of calcium phosphate (5% relative to the CNF compact) were mixed to prepare a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact. The obtained CNF compact had a bottom diameter of 12 cm, a height of 20 mm and a weight of 226 g. A tooth base portion of a complete denture was prepared using the CNF compact obtained in this example. FIG. 2 shows a photograph of a compact obtained by the CNF molding apparatus. Moreover, the CNF compact after cutting is shown in FIG. As described above, according to the present invention, it is possible to obtain a molded body having a thickness that allows cutting and having a uniform interior.

Example 6
(Creation of CNF molded body using CNF-containing slurry substituted with methanol solvent and cutting using the same)
12.5 kg of 2% CNF aqueous dispersion (250 g of CNF) and 12.5 g of calcium phosphate (5% relative to the CNF compact) were used. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact. The obtained CNF molded body had a bottom diameter of 12 cm, a height of 20 mm and a weight of 256 g. A tooth base portion of a complete denture was prepared using the CNF compact obtained in this example. FIG. 4 shows the CNF compact after cutting. As described above, according to the present invention, it is possible to obtain a molded body having a thickness that allows cutting and having a uniform interior.

Examples 7 to 18
(Evaluation of physical properties of CNF molded product)
A CNF molded body was prepared, and (1) a three-point bending test, (2) measurement of surface hardness, (3) measurement of contact angle, (4) measurement of water absorption, and (5) measurement of density were performed. First, each measurement condition is described below.
(1) 3-point bending test The CNF molded body obtained in each example was set to a test piece size of 64 × 10 × 2 mm, and a crosshead speed of 5 mm / min and a distance between supports were measured using a material testing machine INSTRON 5565 manufactured by Instron Japan. A test was performed under the condition of 50 mm, and the bending strength (MPa) and bending elastic modulus (MPa) were calculated.
(2) Measurement of Surface Hardness Using a hardness tester (Teclock durometer type D, manufactured by Teclock), three test pieces were measured at four points each. The pressure surface was brought into close contact so that the indenter was perpendicular to the test piece measurement surface, and the value (HDD) after 3 seconds was measured.
(3) Measurement of contact angle Using a fully automatic contact angle meter manufactured by Kyowa Interface Science Co., Ltd., the contact angle (°) was measured after 10 seconds of dropping distilled water by the droplet method. Measurement was performed at 10 points, and the average value of 8 points excluding the maximum and minimum values was calculated.
(4) Measurement of Water Absorption A test piece was immersed in water and weighed after 3 days. The difference between the original weight and the weight after 3 days was determined and used as the water supply amount (μg/mm3).
(5) Measurement of Density Density was measured from the volume and weight of the test piece.

(Example 7)
2000 g of a 2% CNF aqueous dispersion was used as a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 8)
About 4000 g of the CNF 1% aqueous dispersion was subjected to suction filtration twice with methanol to obtain 2.6% methanol-wet CNF, which was a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 9)
2 g of tricalcium phosphate (5% with respect to the CNF solid content) was added to 2000 g of the CNF 2% aqueous dispersion to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 10)
4 g of tricalcium phosphate (10% with respect to the CNF solid content) was added to 2000 g of the CNF 2% aqueous dispersion to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 11)
To 1400 g of CNF 2% aqueous dispersion, 4 g of tricalcium phosphate (10% relative to the total solid content of CNF and pulp) and bamboo pulp were added so that the weight ratio of CNF and pulp was 7: 3, and a CNF-containing slurry was added. and Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 12)
2000 g of the CNF 2% aqueous dispersion was subjected to suction filtration twice with methanol to obtain 2.5% methanol-wet CNF. To this, 2 g of tricalcium phosphate (5% with respect to the CNF solid content) was added to prepare a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 13)
5 mL of a mixed solution of 94% DMSO / 6% water (v / v) containing CNF 1.5% (w / v) aqueous dispersion and potassium carbonate (20% by weight of pulp) was added at room temperature until a good dispersion was obtained. was stirred. Then, after dispersion, the mixture was heated to 70°C, vinyl laurate was added in an amount corresponding to 1.2 mol per anhydroglucose unit (AGU), the mixture was sealed, and the mixture was allowed to react for 2 hours at 70°C.
Then, it was washed and used as CNF wetted with a methyl methacrylate solution. This was used as a 2% CNF methyl methacrylate solution to obtain a CNF-containing slurry.
Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 14)
5 mL of a mixed solution of 94% DMSO/6% water (v/v) containing 1% (w/v) CNF aqueous dispersion and potassium carbonate (20% by weight of pulp) was stirred at room temperature until a good dispersion was obtained. bottom. Then, after dispersion, the mixture was heated to 70°C, vinyl laurate was added in an amount corresponding to 1.2 mol per anhydroglucose unit (AGU), the mixture was sealed, and the mixture was allowed to react for 2 hours at 70°C.
Then, it was washed and used as CNF wetted with a methyl methacrylate solution. This was made into a 2% CNF methyl methacrylate solution, and 2 g of isocyanate acrylate (Acrylate Laromer LR9000 for dual curing manufactured by BASF) (5% with respect to the solid content concentration of CNF) was added to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 15)
4000 g of the CNF 1% aqueous dispersion was subjected to suction filtration twice with methanol to obtain about 2.6% methanol-wet CNF. To this, 2 g of isocyanate acrylate (Acrylate Laromer LR9000 for dual curing manufactured by BASF) (5% with respect to CNF solid content) was added to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 16)
4000 g of the CNF 1% aqueous dispersion was subjected to suction filtration twice with methanol to obtain about 2.6% methanol-wet CNF. To this, 4 g of isocyanate acrylate (Acrylate Laromer LR9000 for dual curing, manufactured by BASF) (10% with respect to CNF solid content) was dissolved in methanol, and this was added to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 17)
4000 g of the CNF 1% aqueous dispersion was subjected to suction filtration twice with methanol to obtain about 2.4% methanol-wet CNF. To this, 2 g of isocyanate acrylate (BASF's dual-cure acrylate Laromer LR9000) (5% relative to the CNF solid content) is dissolved in methanol, and 100 mg of a polymerization initiator (Wako Pure Chemical Industries, Ltd.'s V-65) is added. to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

(Example 18)
4000 g of CNF 1% aqueous dispersion is subjected to suction filtration twice with acetone to make an acetone solution of about 2.4%, and isocyanate acrylate (Acrylate Laromer LR9000 for dual curing manufactured by BASF) 2 g (5% with respect to CNF solid content) was dissolved in acetone, and 100 mg of a polymerization initiator (V-65 manufactured by Wako Pure Chemical Industries, Ltd.) was added to obtain a CNF-containing slurry. Then, it was put into a CNF forming apparatus using a cylindrical mold, and a load of 60 kg and a mold part was set at 100° C. to produce a compact.

For Examples 7, 8, 9, 10, 11, 12, 15, 16, 17 and 18, the above-described (1) three-point bending test and (5) density measurement were performed. In addition, as Comparative Example 3, a test piece of the same size was produced using an acrylic resin and measured together.

Table 6 shows the results. As can be seen from the table, the flexural modulus values were superior for all examples. Since Examples 10, 11, and 12 have low densities, it is not possible to add metal salts, pulp, or both to CNF-containing slurries in product fields that require low densities. , is very useful.

For Examples 15, 16, 17 and 18, the above-mentioned (2) surface hardness test was carried out. Also, the acrylic resin used in Comparative Example 3 was used for both measurements.

Table 7 shows the results. As can be seen from Table 7, the values were substantially the same as or higher than those of the comparative examples.

For Examples 13 and 14, the above-described (3) contact angle measurement and (5) density measurement were performed. Also, the acrylic resin used in Comparative Example 3 was used for both measurements.

Table 8 shows the results. As can be seen from Table 8, the contact angle was larger than that of the comparative example. Based on this result, it was possible to maintain the hydrophobicity of the CNF molded body.

For Examples 7, 13, 14, 15, 16, 17, and 18, the measurement of water absorption in (4) above was carried out. For results of 1500 μg/mm 3 or more, the evaluation criterion of “unmeasured” was adopted.

Table 9 shows the results. As can be seen from Table 9, in Example 7, although the result was "unmeasured", good results were obtained in other examples. From the results of Examples 13 and 14, it became clear that the CNF molded body using hydrophobized CNF has sufficient hydrophobicity, and from the results of Examples 15, 16, 17, and 18, It was found that hydrophobicity can be imparted to the CNF molded body without using the modified CNF.

Claims (2)

In a CNF molding method in which a load is applied using a steam permeation means that allows steam to permeate a slurry containing cellulose nanofibers (hereinafter referred to as CNF),
The CNF-containing slurry is a CNF-containing slurry containing CNF having an average thickness of 3 to 200 nm and an average length of 0.1 μm or more in a range of 2 to 10% in a water solvent and / or an organic solvent,
When the temperature of the mold part in the vapor permeation means is 100 ° C. and the CNF molded body obtained when the load is 60 kg has a bottom diameter of 12 cm and a height of 20 mm, the density of the molded body is 1.13. A CNF molding method characterized in that it is ˜1.42 g/cm ³ . In a CNF molding method in which a load is applied using a steam permeation means that allows steam to permeate a slurry containing cellulose nanofibers (hereinafter referred to as CNF),
comprising a mold forming a molding cavity with a body portion and a bottom plate at least partially using vapor permeation means, and providing means for introducing CNF into the molding cavity,
The main body comprises at least a part of a mold part using vapor permeation means and an upper plate,
The mold section is provided with heating means for the mold section,
The bottom plate can be fitted inside the main body,
The upper plate is arranged on the opposite side of the bottom plate through the mold part, and the upper plate presses the mold part in the direction of the bottom plate,
The CNF-containing slurry is a CNF-containing slurry containing CNF having an average thickness of 3 to 200 nm and an average length of 0.1 μm or more in a range of 2 to 10% in a water solvent and / or an organic solvent,
A CNF molding method characterized in that the resulting CNF molded body has a density of 1.13 to 1.42 g/cm ³ when the base diameter is 12 cm and the height is 20 mm.

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