JP2014237904A - Composite - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel cellulose nanofiber that can exhibit improved dispersibility in a resin into which it is blended.SOLUTION: The composite includes a cellulose nanofiber and a high molecular part which is formed of a high molecular compound other than a cellulose and is jointed to at least part of a surface of the cellulose nanofiber. The high molecular parts are periodically formed in a direction of continuation of the cellulose nanofiber. Among a surface area S of the cellulose nanofiber existing in a formation area in the direction of continuation being an area where the high molecular parts are formed over a plurality of periods, an area Sc is covered by the high molecular parts, and a ratio (Sc/S) may be 0.6 or larger. In addition, a cross sectional shape of the high molecular parts in a cross section perpendicular to the direction of the continuation of the cellulose nanofiber may change according to a position of the direction of the continuation.

Description

  The present invention relates to a composite, and more particularly to a composite comprising cellulose nanofibers.

The cellulose nanofiber is a nanofiber (for example, width: about 3 nm to 5 μm, length: about several hundred nm to several hundred μm) obtained by defibrating a cellulose-based raw material such as wood. Such cellulose nanofibers have properties such as high strength (about 2 to ³ GPa), high elastic modulus (about 100 GPa), low density (about 1.46 to 1.63 g / cm ³ ), and so on, and are mixed with the resin. It has been proposed to use it as a filler for resin (sometimes called a filler) for improving physical properties (for example, mechanical strength such as bending strength and elastic modulus) (for example, Patent Document 1). reference).

Patent Document 1 states that “cellulose nanofibers have low reactivity with resins and curing agents and dispersibility in resins. Therefore, when cellulose nanofibers are added to the resin, the cellulose nanofibers are not between the cellulose nanofibers and the resin. There is a problem in that the adhesive strength is lowered at the interface, whereby the reinforcing effect of the cellulose nanofibers is not exhibited, and conversely, the mechanical strength such as bending strength is lowered. ”(Patent Document 1 paragraph number) 0004) has been pointed out, and the solution to this problem is to improve the dispersibility in the resin by modifying cellulose nanofibers with a modifying agent and introducing a substituent such as a carboxyl group into cellulose nanofibers. It is disclosed that “to try to do” (paragraph number 0005 of Patent Document 1) has been made.
In addition, in order to improve the dispersibility of cellulose nanofibers in a resin, it has been studied to add a compatibilizing agent (such as maleic acid-modified low molecular weight polyolefin).

JP 2012-229350 A (for example, paragraph numbers 0001 to 0015 in the summary and the detailed description of the invention)

The method of modifying the cellulose nanofibers described in Patent Document 1 with a modifying agent and introducing a substituent such as a carboxyl group into the cellulose nanofibers is as follows: “Modified cellulose nanofibers modified with a modifying agent are sufficient. It is difficult to substitute with TEMPO, and the degree of substitution is low.If TEMPO used as a modifier for cellulose nanofibers remains in the resin composition, it is not preferable from the viewpoint of the environment. " 1 paragraph number 0007).
Furthermore, the method of adding a compatibilizer is that a layer of a compatibilizer composed of a low molecular weight compound is formed at the interface between cellulose nanofibers and a polymer matrix (mainly formed of a thermoplastic polymer) in which the cellulose nanofibers are dispersed. Therefore, there was a problem that the reinforcing effect that sufficiently exhibited the physical properties of the cellulose nanofibers could not be obtained. Cellulose nanofibers can not bear enough.)
Therefore, an object of the present invention is to provide a novel cellulose nanofiber-containing material that can improve the dispersibility in a resin to be blended, in order to solve the problems of the prior art.

As a result of intensive studies to improve the dispersibility of cellulose nanofibers in a resin in which cellulose nanofibers are blended, the present inventors have found that cellulose nanofibers tend to aggregate with each other (cohesive force acting between molecules). ) Has been found to be aggregated in the blended resin and not well dispersed, and the present invention has been completed.
In the present invention, the surface of cellulose nanofibers is coated with another polymer compound to weaken the cohesive force between the cellulose nanofibers, and the cellulose nanofibers are well dispersed in the blended resin.

  The composite of the present invention (hereinafter referred to as “the present composite”) includes cellulose nanofibers and a polymer portion formed of a polymer compound other than cellulose and bonded to at least a part of the surface of the cellulose nanofiber. A complex comprising.

Moreover, this composite_body | complex includes the following aspects (1)-(6).
(1) The polymer portion is periodically formed along the continuous direction of the cellulose nanofiber, and the polymer portion exists in a formation region that is a region along the continuous direction formed over a plurality of cycles. The said composite_body | complex whose ratio (Sc / S) which the area Sc covered with the said polymer part among the surface areas S of a cellulose nanofiber makes | forms with respect to the surface area S is 0.6 or more.
(2) The present composite body, wherein the cross-sectional shape of the polymer portion in a cross section perpendicular to the continuous direction of the cellulose nanofibers changes according to the position in the continuous direction.
(3) The said composite_body | complex with which the said several polymer part is formed so that a cellulose nanofiber may penetrate.
(4) Each of the polymer portions reaches a first position in the continuous direction as the cross-sectional area in a cross section perpendicular to the continuous direction of the cellulose nanofibers advances in the direction from one end to the other end of the cellulose nanofibers. A cross-sectional area increasing portion that monotonously increases, and a cross-sectional area decreasing portion in which the cross-sectional area monotonously decreases as it proceeds in the direction from the first position or the second position existing on the other end side to the other end of the first position. The composite according to (3) above, comprising:
(5) The composite according to the present invention, wherein the polymer portion is spirally wound around cellulose nanofiber.
(6) The composite described above, wherein the polymer compound is polyvinyl alcohol.

The present invention also provides a filler added to the resin (hereinafter referred to as “the present filler”). The filler is a filler comprising the composite (the composite).
The present invention also provides a resin composition (hereinafter referred to as “the present resin composition”). The present resin composition is a resin composition comprising a resin and the present composite.

And this invention provides the manufacturing method (henceforth "this manufacturing method") of this composite_body | complex.
This manufacturing method manufactures the composite_body | complex (present composite_body | complex) formed from the cellulose nanofiber and the polymer part formed with polymer compounds other than cellulose and joined to at least a part of the surface of the cellulose nanofiber. A solution contact step in which the solution of the polymer compound and the cellulose nanofiber are contacted, and after the solution contact step, the amount of the polymer compound dissolved in the solution is reduced, and the surface of the cellulose nanofiber is reduced. A precipitation step of depositing the polymer compound.

The production method includes the following aspects (a) to (d).
(A) A solution contact step includes a fiber dispersion preparation step for preparing a fiber dispersion in which cellulose nanofibers are dispersed in a dispersion medium, a fiber dispersion prepared by a fiber dispersion preparation step, and the polymer compound. And a fiber dispersion mixing step for mixing.
(B) The dispersion medium is capable of dissolving the polymer compound, and in the fiber dispersion liquid mixing step, a solvent that is the same as the dispersion medium is mixed, and the polymer compound is dissolved in the solvent. The manufacturing method according to (a) above.
(C) The present production method, wherein the precipitation step is performed under stirring.
(D) The present manufacturing method, wherein the precipitation step is performed without stirring.
The composites that can be produced by these production methods are novel composites in which a polymer portion is bonded to at least a part of the surface of cellulose nanofibers.

It is a flowchart which shows experiment operation. It is a scanning electron micrograph of the cellulose nanofiber in CeNF-1,3-butanediol dispersion liquid (D). It is a flowchart which shows experiment operation. It is the scanning electron micrograph (a) of the solid in the re-dispersion liquid (J) produced in Example 3, the transmission electron micrograph (b), and the structure schematic diagram (c). It is a scanning electron micrograph of what destroyed the solid which exists in the redispersion liquid (J) produced in Example 3. FIG. 6 is a scanning electron micrograph of a solid in the redispersion liquid (J) prepared in Example 6. FIG. It is the scanning electron micrograph (a) of a solid in the redispersion liquid (J) produced in Example 7, and a structure schematic diagram (b). It is a flowchart which shows experiment operation. It is a graph which shows the elasticity modulus of a composite film. It is a graph which shows the yield strength of a composite film. 6 is a partially enlarged schematic view of a solid (a bead-like crystal) in a redispersion liquid (J) produced in Example 7. FIG. It is a schematic diagram for demonstrating the ratio which the area covered with the said polymer part among the surfaces of a cellulose nanofiber makes with respect to the surface area of a cellulose nanofiber.

The composite comprises cellulose nanofibers and a polymer portion bonded to at least a part of the surface of the cellulose nanofibers.
In this composite, the polymer part is bonded to and covers at least a part of the surface of the cellulose nanofiber to weaken the action of aggregation of the cellulose nanofibers, and when the composite is blended with the resin, the cellulose nanofiber Are well dispersed in the resin.
In addition, since cellulose nanofibers have strong cohesion as described above, it is difficult to disperse them once they are dried, and thus it has been necessary to keep cellulose nanofibers dispersed in water. However, since the present composites have weak cohesive force and can be dispersed again after being dried, the present composite can be handled even in a dry state, and is easy to store, transport and use.

  The cellulose nanofibers constituting this composite can use fibrous cellulose obtained by defibrating cellulose-based raw materials such as wood, and the width of the cellulose fibers (perpendicular to the longitudinal direction of the fibers) (Dimension in the direction) is preferably 5 μm or less, more preferably 500 nm or less, most preferably 50 nm or less (there is no particular lower limit of the width, but usually 3 nm or more), and the length (dimension along the longitudinal direction of the fiber) Although there is no restriction | limiting in particular, Usually, it is several hundred nm-several hundred micrometers. And although the cellulose nanofiber used for this invention does not make delignification treatment essential, what was delignified can be used conveniently.

The polymer part constituting the composite is bonded to at least a part of the surface of the cellulose nanofiber (or the whole surface of the cellulose nanofiber) and covers the at least part of the cellulose nanofibers. The aggregating force of cellulose nanofibers is weakened as compared with the case where the at least part of the surface of the cellulose nanofibers is exposed without being covered with the polymer part. ). For this reason, as the polymer compound that forms the polymer portion, a compound (compound other than cellulose) that weakens the cohesive force when the polymer portion of the polymer compound is formed on the surface of the cellulose nanofiber is selected. It is preferable. As such a polymer compound, polyvinyl alcohol, 6,6-polyamide, 6-polyamide, polymethyl methacrylate, or the like can be used.
In addition, if the thickness of the polymer part constituting the composite (the dimension in the direction perpendicular to the surface of the cellulose nanofiber) is too large, the size of the polymer itself is too large and the effect of adding the cellulose nanofiber is reduced. If it is small, the effect of covering with the polymer portion will not appear, so it may be made a range in which these are compatible. Usually, the lower limit is preferably 3 nm or more, more preferably 8 nm or more, most preferably 10 nm or more, and the upper limit. It is preferably several tens of μm or less, more preferably several μm or less, and most preferably 1 μm or less.

In this composite, the polymer portion is periodically formed along the continuous direction of the cellulose nanofibers, and the polymer portion is a region along the continuous direction formed over a plurality of cycles. The ratio (Sc / S) of the area Sc covered with the polymer portion to the surface area S of the surface area S of the cellulose nanofibers existing in the region may be 0.6 or more.
The polymer part is bonded to at least a part of the surface of the cellulose nanofiber and covers the at least part to weaken the action of aggregation of the cellulose nanofibers. Therefore, the larger the ratio of the at least part of the polymer portion covered with respect to the entire surface of the cellulose nanofiber, the weaker the coagulation action and the better dispersed state can be obtained. For this reason, as shown in FIG. 12, when the polymer portion 501 is periodically (period P) formed along the continuous direction L of the cellulose nanofiber 521, the polymer portion 501 has a plurality of periods P. Ratio of the area Sc covered with the polymer portion 501 to the surface area S of the surface area S of the cellulose nanofiber 521 existing in the formation region Q that is the region along the continuous direction L formed over the surface area S (Sc / S) When the ratio is larger, the polymer portion 501 covers a larger proportion of the surface of the cellulose nanofiber 521, so that the cohesive force of the cellulose nanofiber 521 can be reduced and a good dispersion state of the present composite can be obtained. The ratio (Sc / S) is preferably 0.6 or more, more preferably 0.7 or more, and most preferably 0.9 or more (the upper limit is 1).

In the present composite, the cross-sectional shape of the polymer portion in a cross section perpendicular to the continuous direction of the cellulose nanofiber may be changed according to the position in the continuous direction.
If such a composite is mixed with a resin (the resin is solidified in a state where the composite is dispersed in the matrix of the resin), the composite will be pulled out along the continuous direction of the cellulose nanofibers with respect to the resin portion. Then, since the polymer portion cannot be pulled out unless the resin portion is deformed, a strong reinforcing effect by the composite can be obtained. Due to such a strong reinforcing effect, when the composite is used as a filler added to the resin, the physical properties (for example, bending strength and elastic modulus) of the resin composition can be greatly improved.

The composite may be one in which a plurality of the polymer portions are formed so that cellulose nanofibers penetrate (hereinafter referred to as “skewer composite”).
Thus, the surface of the cellulose nanofiber is formed by taking the form in which the cellulose nanofiber penetrates the plurality of polymer parts (that is, the form in which the cellulose nanofiber is skewed with the plurality of polymer parts). Since the polymer portion can be reliably covered, the cohesive force of cellulose nanofibers can be reduced, and a good dispersion state can be obtained in the resin when the composite is blended with the resin.

In the case of the skewer composite, each of the polymer portions has a cross-sectional area in a cross section perpendicular to the continuous direction of the cellulose nanofibers in the direction of the continuous direction as the cross-sectional area proceeds from one end of the cellulose nanofiber toward the other end. A cross-sectional area increasing portion that monotonously increases to position 1, and a cross-sectional area that monotonously decreases as it proceeds in the direction from the first position or the second position existing on the other end side to the other end side of the first position. And an area-decreasing portion (hereinafter referred to as “the composite having a cross-sectional area increasing portion-decreasing portion”).
By having such a cross-sectional area increasing portion and a cross-sectional area decreasing portion, when this composite is mixed with a resin, the composite is moved in both directions along the continuous direction of the cellulose nanofibers (resin portion). On the other hand, when the composite is pulled out in either the direction from the other end side to the one end side or the direction from the one end side to the other end side), the cross-sectional area increasing portion or the cross-sectional area decreasing portion is a resin. Since the portion is expanded (resistance is large), the resin portion between the one end and the other end can be effectively reinforced.

In the present composite, the polymer portion may be spirally wound around cellulose nanofiber.
In addition to increasing the contact area between the resin part and the composite when the composite is mixed with the resin by taking a form in which the polymer part is spirally wound around the cellulose nanofiber, the resin When the composite is pulled out in a direction along the continuous direction of the cellulose nanofibers, the composite moves so as to cross the continuous direction of the polymer part (straight shaft (the cellulose of the composite After screwing a bolt (corresponding to the complex) corresponding to a male thread (corresponding to the helical polymer part of the complex) on the outer peripheral surface of the nanofiber, the shaft can be rotated without rotating the bolt. The resin portion between the one end and the other end can be effectively reinforced because the state is similar to that of pulling out in the longitudinal direction of the portion (resistance is high).

In the present complex, the polymer compound may be polyvinyl alcohol.
If polyvinyl alcohol is used as the polymer compound that forms the polymer part, the polymer part can be successfully formed so as to cover the surface of the cellulose nanofiber, weakening the cohesive action between the cellulose nanofibers, and good dispersion in the resin The state can be obtained. In addition, the polymer portion can be firmly bonded to the surface of the cellulose nanofiber (polyvinyl alcohol and cellulose have high affinity), and a high reinforcing effect can be exhibited when the composite is mixed with a resin.
The polyvinyl alcohol as the polymer compound can be widely used as long as it crystallizes without any molecular weight limitation. However, the degree of saponification is preferably 90% or more, and more preferably 95% or more.

Although this composite can be used for various applications, as described above, it can be used as a filler to be added to the resin (the present filler). By covering the molecular part, the cohesive strength of cellulose nanofibers can be reduced, and a good dispersion state can be obtained when mixed with resin, greatly increasing the physical properties of the resin composition (for example, bending strength and elastic modulus). Can be improved.
Various resins can be considered as the resin to which the filler is added. For example, polyvinyl alcohol, 6,6-polyamide, 6-polyamide, polymethyl methacrylate, etc. may be used, and in particular, the polymer constituting the composite. If the same resin as the polymer compound forming the part or a resin containing the polymer compound has a strong affinity with the complex, the complex can be dispersed more satisfactorily in the resin and the resin and the complex. The resin composition can be effectively reinforced because the body is firmly bonded.
Also, if the ratio of the amount of the composite to the resin added to the resin as a filler is too small, the effect of the filler will be small, and conversely if it is too large, the dispersibility will be reduced. Usually, the lower limit is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, most preferably 0.005% by weight or more, and the upper limit is preferably 50% by weight or less, more preferably It is 10 wt% or less, most preferably 3 wt% or less.

The present resin composition comprises a resin and the present composite. In the present composite, the surface of the cellulose nanofiber is covered with the polymer portion, thereby reducing the cohesive force of the cellulose nanofiber. Since a good dispersion state can be obtained when mixed, the physical properties (for example, bending strength and elastic modulus) of the resin composition can be greatly improved.
Various resins can be considered as the resin composition. For example, polyvinyl alcohol, 6,6-polyamide, 6-polyamide, polymethyl methacrylate, etc. may be used. If the same resin as the polymer compound forming the polymer part or a resin containing the polymer compound has a strong affinity with the complex, the complex can be dispersed better and the resin and the complex And the resin composition can be effectively reinforced.
Further, if the ratio of the amount of the present composite to the resin mixed with the resin is too small, the effect of adding the present composite is reduced, and conversely, if it is too large, the dispersibility is lowered. In general, the lower limit is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, most preferably 0.005% by weight or more, and the upper limit is preferably 50% by weight or less. Preferably it is 10 weight% or less, Most preferably, it is 3 weight% or less.

This manufacturing method manufactures the composite_body | complex (present composite_body | complex) formed from the cellulose nanofiber and the polymer part formed with polymer compounds other than cellulose and joined to at least a part of the surface of the cellulose nanofiber. A method comprising a solution contacting step and a precipitation step.
In the solution contact step, a solution of a polymer compound that forms a polymer portion is brought into contact with cellulose nanofibers. In the precipitation step, the amount of the polymer compound dissolved in the polymer compound solution in contact with the cellulose nanofibers in the solution contact step is reduced to precipitate the polymer compound on the surface of the cellulose nanofibers. In this way, the polymer compound is deposited on the surface of the cellulose nanofiber to form a polymer portion bonded to the surface of the cellulose nanofiber to produce this composite.
For this reason, the solution of the polymer compound used in the solution contact step can deposit the polymer compound on the surface of the cellulose nanofiber to a desired degree by reducing the amount of the polymer compound dissolved in the precipitation step. Is done.
Various methods can be adopted as a method for reducing the amount of the polymer compound dissolved in the polymer compound solution in the precipitation step. For example, the solubility of the polymer compound in the polymer compound solution is high. When the temperature varies depending on the temperature, a method of changing the temperature so that the solubility is lowered (for example, a method of cooling the polymer compound solution and lowering the temperature when the solubility is lowered when the temperature is lower), the polymer A method of adding an additive that decreases the solubility of the polymer compound in the compound solution (for example, a method of adding a poor solvent), a method of removing the solvent in the polymer compound solution (for example, a method of distilling off the solvent) And a method using these methods in combination.
The ratio of the area where the polymer part is bonded and covered on the surface of the cellulose nanofiber (the ratio of the at least part of the surface of the cellulose nanofiber where the polymer part is bonded and covered) and the thickness of the polymer part (of the cellulose nanofiber In order to increase the dimension in the direction perpendicular to the surface, the amount of decrease in the amount of the polymer compound dissolved in the cellulose nanofibers in the precipitation step may be increased (specifically, for example, the polymer compound solution in the precipitation step) The amount of the polymer compound relative to the cellulose nanofiber in the inside may be increased.) In order to reduce the ratio and the thickness, the amount of decrease in the amount of the polymer compound dissolved in the cellulose nanofibers in the precipitation step may be reduced (specifically, for example, in the polymer compound solution in the precipitation step). The amount of the polymer compound with respect to the cellulose nanofibers may be reduced.)

In this production method, the solution contact step includes a fiber dispersion preparation step for preparing a fiber dispersion in which cellulose nanofibers are dispersed in a dispersion medium, a fiber dispersion prepared by the fiber dispersion preparation step, and the polymer. And a fiber dispersion mixing step of mixing the compound (hereinafter referred to as “dispersed state mixing main production method”).
A fiber dispersion in which cellulose nanofibers are dispersed in a fiber dispersion preparation step is prepared, and then a fiber dispersion (prepared in a fiber dispersion preparation step) and the polymer compound in a fiber dispersion mixing step Since the cellulose nanofibers are sufficiently dispersed in the fiber dispersion in advance, the polymer compound solution and the cellulose nanofibers can be brought into contact with each other in this state (the polymer compound is dissolved in the fiber dispersion). The polymer compound solution comes into contact with the cellulose nanofibers), the polymer compound solution is brought into contact with the cellulose nanofibers with little unevenness, and the surface of the cellulose nanofibers has little unevenness. Form the polymer part with It can be.
The dispersion medium for forming the fiber dispersion is preferably a polar solvent because of its high affinity with cellulose nanofibers and the ability to stably disperse cellulose nanofibers. More preferably, water, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2 are obtained from the point that the shape of the molecule can be controlled (the polymer complex is bonded to the surface of the cellulose nanofiber and the composite of a predetermined form is obtained). Examples include -propanediol, 1,3-propanediol, 1,4-butanediol, glycerin, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and the like, and most preferably 1,3-butanediol. If the ratio (wf / wd) of the amount (wf (g)) of cellulose nanofibers in the fiber dispersion (wd (g)) is too small, the cost of separating and recovering the dispersion medium increases, and if it is too large, the cellulose nanofibers Since it becomes impossible to disperse the fiber stably, it may be within a range where both of these can be achieved. Usually, the lower limit is preferably 0.0005% by weight or more, more preferably 0.001% by weight or more, and most preferably The upper limit is preferably 10% by weight or less, more preferably 5% by weight or less, and most preferably 0.5% by weight or less.
If the ratio of the cellulose nanofiber content in the mixture of the fiber dispersion and the polymer compound in the fiber dispersion mixing step is too small, the amount of waste liquid increases, and if it is too large, the cellulose nanofibers aggregate. The lower limit is usually preferably 0.0001% by weight or more, more preferably 0.0005% by weight or more, most preferably 0.001% by weight or more, and preferably the upper limit. Is 0.5% by weight or less, more preferably 0.1% by weight or less, and most preferably 0.05% by weight or less. And, if the content of the polymer compound in the mixture in which the fiber dispersion and the polymer compound are mixed in the fiber dispersion mixing step is too small, it becomes impossible to sufficiently cover the cellulose nanofibers. Since the cellulose nanofibers are crystallized without using the core material, they may be in a range where both of them are compatible. Usually, the lower limit is preferably 0.0005% by weight or more, more preferably 0.0025% by weight or more, and most preferably Is 0.005% by weight or more, and the upper limit is preferably 2.5% by weight or less, more preferably 0.5% by weight or less, and most preferably 0.25% by weight or less.

In the case of this production method, the dispersion medium is capable of dissolving the polymer compound, and in the fiber dispersion liquid mixing step, a solvent that is the same as the dispersion medium is mixed, and the polymer compound is mixed with the polymer compound. It may be dissolved in a solvent.
In this manner, in the fiber dispersion mixing step, the fiber dispersion, the polymer compound, and the same solvent as the dispersion medium forming the fiber dispersion (dissolve the polymer compound) are mixed. Therefore, a part of the polymer compound (the remainder of the part is dissolved in the dispersion medium of the fiber dispersion) is smoothly dissolved in the solvent to form a polymer compound solution and the formed polymer compound Since the solution and the fiber dispersion are smoothly mixed, the fiber dispersion and the polymer compound can be mixed smoothly and quickly.
In addition, as the same dispersion medium and solvent used here, those that can dissolve the polymer compound and deposit the polymer compound as desired on the surface of the cellulose nanofiber in the precipitation step are widely used. However, since it has high affinity with cellulose nanofibers and cellulose nanofibers can be stably dispersed, it is preferably a polar solvent and can control the form of the polymer deposited on the surface of cellulose nanofibers. More preferably, water, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1, 3 are obtained (by joining the polymer portion to the surface of the cellulose nanofiber while obtaining the composite in a predetermined form). -Propanediol, 1,4-butanediol, Glycerin, dimethyl sulfoxide, can be exemplified a N- methyl-2-pyrrolidone, most preferably 1,3-butanediol.
In addition, if the ratio of the content of cellulose nanofibers in the mixture in which the fiber dispersion, the polymer compound and the solvent are mixed in the fiber dispersion mixing step is too small, the amount of waste liquid containing the solvent increases and the amount is too large. And the cellulose nanofibers may be aggregated, and may be within a range where both of them are compatible. Usually, the lower limit is preferably 0.0001% by weight or more, more preferably 0.0005% by weight or more, and most preferably 0.001% by weight. The upper limit is preferably 0.5% by weight or less, more preferably 0.1% by weight or less, and most preferably 0.05% by weight or less. In addition, if the content of the polymer compound in the mixture in which the fiber dispersion and the polymer compound are mixed in the fiber dispersion mixing step is too small, it becomes impossible to sufficiently cover the cellulose nanofibers. Since the cellulose nanofibers are crystallized without using the core material, they may be in a range where both of them are compatible. Usually, the lower limit is preferably 0.0005% by weight or more, more preferably 0.0025% by weight or more, and most preferably Is 0.005% by weight or more, and the upper limit is preferably 2.5% by weight or less, more preferably 0.5% by weight or less, and most preferably 0.25% by weight or less.

In this production method, the precipitation step may be performed with stirring.
In this way, a plurality of the polymer portions are formed so that the cellulose nanofibers penetrate, and each of the polymer portions has a cross-sectional area in a cross section perpendicular to the continuous direction of the cellulose nanofibers. A cross-sectional area increasing portion that monotonously increases to the first position in the continuous direction as it proceeds in the direction from one end of the fiber to the other end, and the second position existing on the other end side from the first position or the first position. The composite body having the cross-sectional area decreasing portion in which the cross-sectional area decreases monotonously as it goes in the direction from the other end to the other end can be successfully formed. As will be described later, when the precipitation step is performed without stirring, the composite part is formed in a form in which the polymer portion is spirally wound around the cellulose nanofiber, but when the stirring in the precipitation step is increased, the cross-sectional area increasing portion and The area where the cross-sectional area is reduced grows. In particular, each of the polymer portions has a substantially spherical shape (that is, the first position and the second position substantially coincide, the cross-sectional area increasing portion has a substantially hemispherical shape, and the cross-sectional area decreasing portion has a substantially hemispherical shape. Thus, a substantially spherical shape of 1 is formed by the cross-sectional area increasing portion and the cross-sectional area decreasing portion), and if the substantially spherical polymer portion is used, a filler ( When used as the present filler), a reinforcing effect can be successfully obtained by allowing the resin to enter between the substantially spherical polymer portions adjacent to each other in the continuous direction.

In this manufacturing method, the precipitation step may be performed without stirring.
In this way, the present composite in a form in which the polymer portion is spirally wound around the cellulose nanofiber can be formed, and if such a composite is mixed with a resin, contact between the resin portion and the present composite is achieved. In addition to the increase in area, when the composite is pulled out in the direction along the continuous direction of the cellulose nanofiber with respect to the resin part, the composite moves so as to cross the continuous direction of the polymer part (straight After screwing a bolt (corresponding to the present composite) with a male screw (corresponding to the polymer portion of the present composite) threaded on the outer peripheral surface of the shaft (corresponding to the cellulose nanofiber of the present composite) Therefore, the resin portion between the one end and the other end can be effectively reinforced.

The composite that can be produced by this production method has a function in which the polymer part covers at least a part of the surface of the cellulose nanofiber, thereby weakening the action of aggregation of the cellulose nanofibers. The fiber is well dispersed in the resin and exhibits a good reinforcing effect.
Moreover, since the composite body which can be manufactured by this manufacturing method has a weak cohesive force, it can be dried and dispersed again, so that it can be handled even in a dry state, so that it is easy to store, transport and use.

  Examples are given below in order to specifically explain the present invention. However, the present invention is not limited by these examples.

(Example 1) Preparation of Cellulose Nanofiber Dispersion As cellulose nanofiber (CeNF), here is a model name “KY100G” (trade name: 10% solid content of CeNF, manufactured by Daicel Finechem Co., Ltd.). Water dispersion) was used.
The experimental operation will be described below with reference to the flowchart of FIG.
3 g of CeNF-containing composition (A) having the model number “KY100G” (solid content 10%) of the above-mentioned trade name “Serish” (registered trademark) (that is, the solid content is 0.3 g) and 200 g of distilled water ( B) was placed in a beaker and sufficiently mixed by irradiating with ultrasonic waves for 1 hour using an ultrasonic cleaner (BRANSON, model 2510J-MT) (s11).
After mixing (s11), the mixture was allowed to stand for 7 days (s13).
After standing (s13), the supernatant in the beaker 101 was fractionated so that 3 × 10 ⁻² g of CeNF was contained (s15). The purpose of mixing the distilled water (B) with the CeNF-containing composition (A) in this s11 and allowing it to stand for 7 days (s13) and then separating the supernatant (s15) is that it is completely dispersed in water. This is in order to obtain CeNF, which is allowed to stand after irradiation with ultrasonic waves, precipitates agglomerated and precipitates, and uses a dispersed supernatant. In addition, the amount of the supernatant liquid in s15 was calculated as follows. The weight w1 (g) of the petri dish that is a tare is weighed in advance, and then an appropriate amount of the supernatant liquid in the beaker 101 after standing (s13) is placed in the petri dish, and the total weight w2 (g) including the petri dish ). Thereafter, the petri dish was vacuum-dried (60 ° C.) for 4 hours, water contained in the supernatant liquid was completely discharged, and the total weight w3 (g) including the petri dish was measured. The concentration Cc of CeNF in the supernatant was calculated by (w3-w1) / (w2-w1) × 100 (specifically, here Cc = 9.8 × 10 ⁻² wt%), and fractionated (s15 ) The amount of supernatant liquid W (g) = 3 × 10 ⁻² g / Cc (specifically, W = 30.6 g) was fractionated.
The supernatant W (g) separated (s15) and 30 ml of 1,3-butanediol (C) were placed in a 100 ml eggplant flask 103.
The eggplant flask 103 was distilled under reduced pressure (s17) in a water bath at 40 ° C. to distill off the water, thereby preparing a CeNF-1,3-butanediol dispersion (D) as a fiber dispersion. As described above, CeNF-1,3-butanediol dispersion (D) contains CeNF3 × 10 ⁻² g and 1,3-butanediol 30 ml. In this case, CeNF as a fiber dispersion is used. The ratio (wf / wd) of the amount (wf (g)) of cellulose nanofibers in the 1,3-butanediol dispersion (D) (wd (g)) is 9.8 × 10 ⁻² wt%. .
CeNF in the CeNF-1,3-butanediol dispersion (D) was observed with a scanning electron microscope (SEM observation). The sample for observation at this time was produced as follows. A mica plate was fixed with a conductive tape on a sample stage for SEM, and CeNF-1,3-butanediol dispersion (D) was dropped onto the cleavage plane. After drying in a desiccator, the surface was gold coated at 2 mA for 15 minutes using an ion coater (manufactured by Eiko Co., Ltd., model number IB-3). Thereafter, observation was performed at an acceleration voltage of 5 kV using a scanning electron microscope (model number JSM-6320F manufactured by JEOL Ltd.). The obtained SEM photograph is shown in FIG. FIG. 2 revealed that CeNF was well dispersed in the CeNF-1,3-butanediol dispersion (D). The thickness of CeNF in the CeNF-1,3-butanediol dispersion (D) was 53 nm ± 8 nm (standard deviation).

(Example 2) Preparation of crystallization solution Here, polyvinyl alcohol (saponification degree: 99% or more, average molecular weight: 89000 to 98000) manufactured by Sigma-Aldrich Japan LLC was used as polyvinyl alcohol (PVA).
Hereinafter, the experimental operation will be described with reference to the flowchart of FIG.
0.0972 g of CeNF-1,3-butanediol dispersion (D) prepared in Example 1, 0.0005 g of the above-mentioned polyvinyl alcohol (E), and 4.923 g of 1,3-butanediol (F) as a solvent. Were placed in a container 107 (here, a test tube) and mixed (s19) to prepare a crystallization solution (G).
Crystallization in which CeNF-1,3-butanediol dispersion (D) (fiber dispersion), polyvinyl alcohol (E) (the polymer compound) and 1,3-butanediol (F) (solvent) are mixed. The ratio of 0.0001 g of cellulose nanofibers in 5 g of the solution (G) (mixture) is 0.002% by weight. The proportion of 0.0005 g of polyvinyl alcohol (E) (the polymer compound) in 5 g of the crystallization solution (G) (mixture) is 0.01% by weight.

(Example 3) Crystallization of polyvinyl alcohol (without stirring)
As shown in the flowchart of FIG. 3, the crystallization solution (G) prepared in Example 2 was heated in an oil bath and heated to 185 ° C. (s21), whereby the PVA in the crystallization solution (G) was completely removed. Dissolved in.
The crystallization solution (G) having been heated (s21) was then cooled in an oil bath and cooled to 142 ° C (s23) without stirring at a cooling rate of 5 ° C / hour. In the process of lowering the temperature (s23), the crystallization solution (G) became cloudy at 157.5 ° C. (start of crystallization of PVA). In addition, when the 1,3-butanediol solution of PVA, which is different only in that it does not contain CeNF as compared with the crystallization solution (G), was similarly heated (s21) and cooled (s23), it was 154.0 ° C. (PVA is crystallized from a higher temperature in the case where CeNF is present than in the case where CeNF is not present) because of white turbidity (start of crystallization of PVA), and PVA crystallization in the crystallization solution (G) It was revealed that CeNF functions as a crystal nucleus. In addition, the amount of decrease in the amount of polyvinyl alcohol (the polymer compound) dissolved per unit mass of cellulose nanofiber in the temperature lowering (s23) process is 0.0005 (gPVA) /0.0001 g (gCeNF) = 5 (gPVA / gCeNF). there were.
After the temperature drop (s23), here, by solid-liquid separation (s25) by suction filtration (using Isopore GTTP2500 manufactured by Millpore as the filter medium. The same filter medium was used in s25 below). 3-Butanediol was removed, distilled water (I) was added to the separated solid (H) and mixed (s27) to prepare a redispersion liquid (J) (from 1,3-butanediol to distilled water). Solvent substitution).

(Example 4) Observation of solid in redispersion liquid (J) by electron microscope The solid in redispersion liquid (J) prepared in Example 3 was applied to a scanning electron microscope (SEM) and a transmission electron microscope (TEM). And observed. The specific procedure is as follows.
First, a mica plate was fixed to a SEM sample stage with a conductive tape, and a suspension of the redispersion liquid (J) was dropped onto the cleavage plane. After drying in a desiccator, the surface was gold coated at 2 mA for 15 minutes using an ion coater (manufactured by Eiko Co., Ltd., model number IB-3). Thereafter, observation was performed at an acceleration voltage of 5 kV using a scanning electron microscope (model number JSM-6320F manufactured by JEOL Ltd.). FIG. 4A shows the obtained SEM photograph.
In addition, the suspension of the redispersion liquid (J) is placed on a trade name “Carbon 20 support film” manufactured by EM Japan Co., Ltd., which has a carbon film thickness of 15 to 20 nm, using a platinum wire loop, and a desiccator. Dried in. Thereafter, observation was performed at an accelerating voltage of 200 kV using a transmission electron microscope (model number JEM-2000EX II manufactured by JEOL Ltd.). FIG. 4B shows a TEM photograph obtained.
Fibrous crystals were observed in both the SEM photograph of FIG. 4 (a) and the TEM photograph of FIG. 4 (b). This fibrous crystal has a thickness of 503 ± 35 nm, which is larger than that of the original CeNF (53 nm ± 8 nm), and appears to have a left-handed rope-like structure. It was. From these facts, such a rope-like fibrous crystal has CeNF as a core as schematically shown in FIG. 4C (cross section cut at the center of CeNF), and a PVA band centering on the core. It was inferred that CeNF was covered so as to be spirally wound.

(Example 5) Confirmation of structure of rope-like fibrous crystal The solid present in the redispersion liquid (J) has CeNF as a core as schematically shown in FIG. 4 (c), and in the longitudinal direction of the core. In order to confirm whether or not the PVA surrounds the core along the rope, the rope-like fibrous crystals were broken and observed. Specifically, the redispersion liquid (J) suspension prepared in Example 3 was irradiated with ultrasonic waves for 8 hours using an ultrasonic cleaner (BRANSON, model number 2510J-MT). The sample after ultrasonic irradiation was observed by SEM in the same manner as in the scanning electron microscope (SEM) observation of Example 4. FIG. 5 shows the obtained SEM photograph. As shown in FIG. 5, a fiber having a thickness of about 60 nm was confirmed at the center of the broken portion of the sample. Since this fiber is comparable to the thickness of CeNF (53 nm ± 8 nm), the fiber observed in FIG. 5 is CeNF, and the solid in the redispersion liquid (J) is schematically shown in FIG. As shown in Fig. 1, it was found that CeNF is a core, and PVA spirally surrounds the core along the longitudinal direction of the core.

(Example 6) Example of increasing amount (preparation of crystallization solution and PVA crystallization (no stirring))
The operations of Example 2 and Example 3 were increased.
This will be described with reference to the flowchart of FIG.
0.972 g of CeNF-1,3-butanediol dispersion (D) prepared in Example 1, 0.005 g of the polyvinyl alcohol (E) described above, and 49.023 g of 1,3-butanediol (F) as a solvent. Were placed in a container (here, a 100 ml eggplant flask was used instead of the test tube in Example 2) and mixed (s19) to prepare a crystallization solution (G). Crystallization in which CeNF-1,3-butanediol dispersion (D) (fiber dispersion), polyvinyl alcohol (E) (the polymer compound) and 1,3-butanediol (F) (solvent) are mixed. The ratio of 0.001 g of cellulose nanofibers in 50 g of the solution (G) (mixture) is 0.002% by weight. Further, the proportion of 0.005 g of polyvinyl alcohol (E) (the polymer compound) in 50 g of the crystallization solution (G) (mixture) is 0.01% by weight.
Thereafter, the crystallization solution (G) was heated in an oil bath and heated to 185 ° C. (s21) to completely dissolve the PVA in the crystallization solution (G).
The crystallization solution (G) having been heated (s21) was then cooled in an oil bath and cooled to 142 ° C (s23) without stirring at a cooling rate of 5 ° C / hour. In the temperature drop (s23) process, the amount of decrease in the amount of polyvinyl alcohol (the polymer compound) dissolved per unit mass of cellulose nanofiber was 0.005 (gPVA) /0.001 (gCeNF) = 5 (gPVA / gCeNF). .
After the temperature drop (s23), here, by solid-liquid separation (s25) by suction filtration, 1,3-butanediol is removed, and distilled water (I) is added to the separated solid (H) and mixed ( s27) to prepare a redispersion liquid (J) (solvent substitution from 1,3-butanediol to distilled water).
The solid in the obtained redispersion (J) was observed with a scanning electron microscope (SEM) in the same manner as in Example 4. FIG. 6 shows the obtained SEM photograph. The solid SEM photograph shown in FIG. 6 shows the same structure as the SEM photograph of Example 4, and crystals of the same form (rope-like fibrous crystals) are obtained in Example 4 and Example 6. It became clear that

(Example 7) Example of increasing amount (preparation of crystallization solution and PVA crystallization (with stirring))
This will be described with reference to the flowchart of FIG.
0.972 g of CeNF-1,3-butanediol dispersion (D) prepared in Example 1, 0.005 g of the polyvinyl alcohol (E) described above, and 49.023 g of 1,3-butanediol (F) as a solvent. Were placed in a container (100 ml eggplant flask) and mixed (s19) to prepare a crystallization solution (G). Crystallization in which CeNF-1,3-butanediol dispersion (D) (fiber dispersion), polyvinyl alcohol (E) (the polymer compound) and 1,3-butanediol (F) (solvent) are mixed. The ratio of the content of cellulose nanofibers in the solution (G) (mixture) is the same as in Example 6 described above.
Thereafter, the crystallization solution (G) was heated in an oil bath and heated to 185 ° C. (s21) to completely dissolve the PVA in the crystallization solution (G).
The crystallized solution (G) that has been heated (s21) is cooled in an oil bath while stirring with a magnetic stirrer and cooled to 142 ° C at a cooling rate of 5 ° C / hour (s23). )did. It should be noted that the stirring during the temperature drop (s23) needs to be such that CeNF does not aggregate or settle. Specifically, here, a strong magnetic stirrer (trademark “EYELA”) manufactured by Tokyo Rika Kikai Co., Ltd. is used. , Model No. “RCX-1000S”, stirred as a stirring speed control knob “4”), and the stirring bar was a football type (thickness 10 mm, length 20 mm). The amount of decrease in the amount of polyvinyl alcohol (the polymer compound) dissolved per unit mass of cellulose nanofiber in the temperature lowering (s23) process is the same as in Example 6 described above.
After the temperature drop (s23), here, by solid-liquid separation (s25) by suction filtration, 1,3-butanediol is removed, and distilled water (I) is added to the separated solid (H) and mixed ( s27) to prepare a redispersion liquid (J) (solvent substitution from 1,3-butanediol to distilled water).
The solid in the obtained redispersion (J) was observed with a scanning electron microscope (SEM) in the same manner as in Example 4. FIG. 7A shows the obtained SEM photograph. The SEM photograph of FIG. 7 (a) shows a form in which spherical crystals are continuously formed along the longitudinal direction of the core with CeNF as the core, and the spherical shape as schematically shown in FIG. 7 (b). A bead-like crystal in which the PVA crystals were connected by CeNF was obtained. Thus, depending on the presence or absence of stirring during the temperature drop (s23), a rope-like fibrous crystal as shown in FIGS. 4 and 6 (without stirring) and a bead-like crystal as shown in FIG. 7 (with stirring) , Can be created freely.

(Example 8) Production of composite film by solution casting method This will be described with reference to the flowchart of FIG.
First, an aqueous solution of polyvinyl alcohol (manufactured by Sigma Aldrich Japan G.K., saponification degree of 99% or more, average molecular weight of 89000 to 98000) was prepared. Specifically, 0.25 g of polyvinyl alcohol (K), 20 g of distilled water (L), and a stirrer 108 are placed in a 100 ml eggplant flask 111 and heated with stirring in an oil bath at 95 ° C. for 1 hour. Polyvinyl alcohol (K) was completely dissolved (s31). After heating and dissolving (s31), the mixture was allowed to cool to room temperature (s33). After standing to cool (s33), the redispersion (J) was poured into the PVA aqueous solution from which the stirrer 108 was taken out. The injection amount of the re-dispersion liquid (J) was determined so that the CeNF content in the injected re-dispersion liquid (J) was 2.5 × 10 ⁻⁴ g. It was determined in the same manner as the amount of the supernatant liquid in s15. In detail, the weight w1 (g) of the petri dish which is a tare was weighed in advance, and then an appropriate amount of the redispersion liquid (J) was added to the petri dish, and the total weight w2 (g) including the petri dish was measured. Thereafter, the petri dish was vacuum-dried (60 ° C.) for 4 hours, water contained in the redispersion liquid (J) was completely skipped, and the total weight w3 (g) including the petri dish was measured. The concentration Cc of CeNF in the redispersion (J) is calculated by (w3−w1) / (w2−w1) × 100, and the amount W (g) of the redispersion (J) to be injected = 2.5 × 10 ⁻⁴ g / Cc was calculated. After injecting the redispersion liquid (J) into the PVA aqueous solution, the redispersion liquid (J) is sufficient in the PVA aqueous solution by irradiating ultrasonic waves with an ultrasonic cleaner (BRANSON, model 2510J-MT) for 1 hour. Mixed to disperse (s35). After the re-dispersed liquid (J) was mixed with the PVA aqueous solution (s35), the mixed liquid was transferred to a screw tube, and defoamed by centrifuging at 2000 rpm for 30 minutes (s37). After defoaming (s37), the defoamed solution (mixture of PVA aqueous solution and redispersion liquid (J)) was poured into Teflon petri dish 113 (s39), and this was dried in a dryer at 70 ° C. (s41). I let you. After drying (s41), the composite film 115 was taken out from the Teflon petri dish 113. In addition, the case where the redispersion liquid (J) produced in Example 6 (containing the rope-like fibrous crystal) is used as the redispersion liquid (J) is referred to as Example 8a. The case where the redispersion liquid (J) (containing bead-like crystals) prepared in Example 7 is used as J) is referred to as Example 8b. In the composite film 115, the ratio of the amount of the composite added to 0.25 g of polyvinyl alcohol (resin) 2.5 × 10 ⁻⁴ g in both Examples 8a and 8b was 0.1% by weight.

(Example 9) Tensile test of composite film From the composite film 115 produced in Example 8 (8a, 8b), a strip-shaped test piece having a main surface of 20 mm x 5 mm in a rectangular shape was cut out. A pair of 5 mm × 5 mm square filter papers are prepared, and one of the pair of square filter papers is attached so that one side thereof is along one side of a pair of rectangular short sides formed by the main surface of the strip-shaped test piece. By sticking the other of the pair of square filter papers along the other side of a pair of rectangular short sides whose one side is formed by the main surface of the strip-shaped test piece, an effective length of 10 mm using the strip-shaped test piece. A sample for tension (20 mm-2 × 5 mm) was prepared. Thereafter, the tensile sample was dried in a heat vacuum at 40 ° C. for 8 hours to remove moisture contained in the tensile sample. The tensile sample after drying was subjected to a tensile test at a rate of 4 mm per minute using a tensile tester (manufactured by Imada Manufacturing Co., Ltd., model number SV-201NA), and the elastic modulus and yield stress were calculated. In addition, in order to evaluate the effect of adding the redispersion liquid (J) to the PVA aqueous solution as a raw material for the composite film, a tensile sample made from a film formed using the PVA aqueous solution without the redispersion liquid (J) as a raw material. (Referred to as “PVA” in FIGS. 9 and 10) and CeNF (product name “KY100G”, trade name “Selish” (registered trademark) manufactured by Daicel Finechem Co., Ltd.) instead of the redispersion liquid (J). Added to the aqueous solution (specifically, the above-mentioned CeNF-1,3-butanediol dispersion (D) was added in an amount such that the CeNF content contained in the dispersion was 2.5 × 10 ⁻⁴ g. The CeNF concentration in the CeNF-1,3-butanediol dispersion (D) was determined in the same manner as the CeNF concentration Cc in determining the amount of supernatant liquid in s15 described above). Tensile tests were similarly conducted on samples for tension (shown as “dispersed serisch / PVA” in FIGS. 9 and 10) made from a film formed from a raw material. Moreover, in FIG.9 and FIG.10, the result of Example 8a was represented as "rope-like fiber / PVA", and the result of Example 8b was represented as "bead-like fiber / PVA".
The elastic modulus in FIG. 9 was improved by “Rope fiber / PVA” in Example 8a. The yield stress of FIG. 10 is improved in both “rope-like fiber / PVA” of Example 8a and “bead-like fiber / PVA” of Example 8b, and particularly in “bead-like fiber / PVA” of Example 8b. Remarkably improved.

As described above, the solid in the redispersion liquid (J) prepared in Example 3 (FIGS. 4A and 4B. Rope-like fibrous crystals), the redispersion liquid prepared in Example 6 ( J) (Fig. 6. Rope-like fibrous crystals), and the solid (J. bead-like crystals) in the redispersion liquid (J) prepared in Example 7 are cellulose nanofiber CeNF, A polymer portion formed of a polymer compound other than cellulose (here, polyvinyl alcohol PVA) and bonded to at least a part of the surface of the cellulose nanofiber CeNF (as “PVA” in FIGS. 4C and 7B) And a composite comprising:
And the solid (FIG. 4 (a), FIG.4 (b). Rope-like fibrous crystal) in the re-dispersion liquid (J) produced in Example 3, the re-dispersion liquid (J) produced in Example 6 Both of the solid (FIG. 6, rope-like fibrous crystals) and the solid (FIG. 7, bead-like crystals) in the redispersion liquid (J) prepared in Example 7 were both polymer parts (FIG. 4 (c), “PVA” in FIG. 7 (b)) is periodically formed along the continuous direction of the cellulose nanofiber CeNF, and the polymer portion is formed in the continuous direction formed over a plurality of periods. The area Sc covered with the polymer portion ("PVA" in FIGS. 4C and 7B) of the surface area S of the cellulose nanofiber CeNF existing in the formation region Q, which is a region along the surface, is the surface area S. The ratio (Sc / S) to be made is 0.6 or more (here, approximately 1) That).

Further, the solid in the redispersion liquid (J) prepared in Example 3 (FIGS. 4A and 4B. Rope-like fibrous crystals), the redispersion liquid (J) prepared in Example 6 Both the solid in the solid (FIG. 6, rope-like fibrous crystals) and the solid in the redispersion liquid (J) prepared in Example 7 (FIG. 7, bead-like crystals) are continuous cellulose nanofibers CeNF. The cross-sectional shape of the polymer portion (“PVA” in FIGS. 4C and 7B) in a cross section perpendicular to the direction changes according to the position in the continuous direction.
The solid (FIG. 7, bead-like crystals) in the redispersion liquid (J) prepared in Example 7 is a plurality of polymer parts (“PVA” in FIG. 7B) so that the cellulose nanofiber CeNF penetrates. )) Is formed.
In the solid (FIG. 7, bead-like crystals) in the redispersion liquid (J) prepared in Example 7, each of the polymer portions 501 is in the continuous direction of the cellulose nanofibers 521 as shown in FIG. As the cross-sectional area in a cross section perpendicular to the cross section proceeds in the direction from one end 521a to the other end 521b of the cellulose nanofiber 521 (the direction from left to right in FIG. 11), the first position in the continuous direction (in FIG. 11). , A cross-sectional area increasing portion 501a that monotonously increases up to point V), and a second position (point V in FIG. 11, that is, the second position in FIG. 11). The position is located at the first position) to the other end 521b, and has a cross-sectional area decreasing portion 501b in which the cross-sectional area monotonously decreases. Here, each of the polymer portions 501 has a substantially spherical shape due to the cross-sectional area increasing portion 501a and the cross-sectional area decreasing portion 501b (the cross-sectional area increasing portion 501a has a hemispherical shape, and the cross-sectional area decreasing portion 501b. Is also hemispherical.)

In the redispersion liquid (J) prepared in Example 3, the solid (FIGS. 4A and 4B, rope-like fibrous crystals) and in the redispersion liquid (J) prepared in Example 6. The solid (FIG. 6, rope-like fibrous crystal) has a form in which the polymer portion PVA is spirally wound around cellulose nanofiber CeNF.
Solids in the redispersion liquid (J) prepared in Example 3 (FIGS. 4A and 4B. Rope-like fibrous crystals), in the redispersion liquid (J) prepared in Example 6 Both of the solid (FIG. 6. Rope-like fibrous crystals) and the solid (FIG. 7. bead-like crystals) in the redispersion liquid (J) prepared in Example 7 showed that the polymer compound was polyvinyl alcohol PVA. It is.
Solids in the redispersion liquid (J) prepared in Example 3 (FIGS. 4A and 4B. Rope-like fibrous crystals), in the redispersion liquid (J) prepared in Example 6 Both solid (Fig. 6, rope-like fibrous crystals) and solid (Fig. 7, bead-like crystals) in the redispersion liquid (J) prepared in Example 7 were used for resin addition to reinforce the resin. It can be used as a filler (filler), and a reinforced resin composition can be formed by adding one or both of such rope-like fibrous crystals and bead-like crystals to the resin.

  1 and FIG. 3 (Example 1, Example 2, Example 3, Example 6, Example 7), cellulose nanofiber CeNF and a polymer compound other than cellulose (Example 1). And a polymer part (shown as “PVA” in FIGS. 4 (c) and 7 (b)) formed by polyvinyl alcohol (PVA) and bonded to at least a part of the surface of the cellulose nanofiber CeNF. A solution contact step in which a solution of the polymer compound (polyvinyl alcohol PVA) and cellulose nanofiber CeNF are contacted (here, the supernatant liquid separated (s15) and 1,3-butanediol ( C) is placed in the eggplant flask 103, and water is distilled off from the eggplant flask 103 by vacuum distillation (s17). , 3-butanediol dispersion (D), and then CeNF-1,3-butanediol dispersion (D), polyvinyl alcohol (E), and 1,3-butanediol (F) in container 107 After the step of mixing (s19) and the solution contact step, the amount of the polymer compound (polyvinyl alcohol PVA) in the solution is reduced, and the polymer compound (polyvinyl alcohol PVA) is placed on the surface of the cellulose nanofiber CeNF. And a precipitation step (in this case, a temperature drop (s23)).

And the manufacturing method (Example 1, Example 2, Example 3, Example 6, Example 7) of the composite_body | complex shown by FIG.1 and FIG.3 has a solution contact step using cellulose nanofiber CeNF as a dispersion medium ( Here, a fiber dispersion preparation step (here, preparative (preparation (C)) of preparing a fiber dispersion (here, CeNF-1,3-butanediol dispersion (D)) dispersed in 1,3-butanediol (C)). s15) The supernatant and 1,3-butanediol (C) are put into the eggplant flask 103, and water is distilled from the eggplant flask 103 by vacuum distillation (s17)), and the fiber dispersion preparation step is used. For mixing the prepared fiber dispersion (CeNF-1,3-butanediol dispersion (D)) and the polymer compound (polyvinyl alcohol (E)) Dispersion liquid mixing steps (combined in vessel 107 (s19) and operations to prepare the crystallization solution (G)), is made of a.
And the manufacturing method (Example 1, Example 2, Example 3, Example 6, Example 7) of the composite_body | complex shown by FIG.1 and FIG.3 is the said dispersion medium (1,3-butanediol (C )) Is capable of dissolving the polymer compound (polyvinyl alcohol (E)), and in the fiber dispersion mixing step (operation for preparing the crystallization solution (G) by mixing (s19) in the container 107) A solvent (here, 1,3-butanediol (F)) that is the same as the dispersion medium (1,3-butanediol (C)) is mixed, and the polymer compound (polyvinyl alcohol (E)) is mixed with the solvent. It is dissolved in (1,3-butanediol (F)).

In Example 7, the precipitation step is performed with stirring, and in Examples 3 and 6, the precipitation step is performed without stirring.
In the redispersion liquid (J) produced in Example 6, the composite (FIG. 4 (a), FIG. 4 (b). Rope-like fibrous crystal) in the redispersion liquid (J) produced in Example 3 The composite part (FIG. 6: rope-like fibrous crystals) and the composite (FIG. 7. bead-like crystals) in the redispersion liquid (J) prepared in Example 7 are both cellulose in the polymer portion. By bonding and covering at least a part of the surface of the nanofiber CeNF, the action of aggregation of the cellulose nanofibers CeNF is weakened, and when mixed with the resin, the nanofiber CeNF is well dispersed in the resin.

DESCRIPTION OF SYMBOLS 101 Beaker 103 Eggplant flask 107 Container 108 Stirrer 111 Eggplant flask 113 Teflon petri dish 115 Composite film 501 Polymer part 521 Cellulose nanofiber Q formation region

Claims (15)

Cellulose nanofiber,
A polymer part formed of a polymer compound other than cellulose and bonded to at least a part of the surface of the cellulose nanofiber;
A complex comprising The polymer portion is periodically formed along the continuous direction of cellulose nanofibers,
Of the surface area S of the cellulose nanofiber existing in the formation region, which is a region along the continuous direction in which the polymer portion is formed over a plurality of periods, the area Sc covered by the polymer portion forms with respect to the surface area S. The composite according to claim 1, wherein the ratio (Sc / S) is 0.6 or more.   The composite according to claim 1 or 2, wherein a cross-sectional shape of the polymer portion in a cross section perpendicular to the continuous direction of the cellulose nanofibers changes according to a position in the continuous direction.   The composite according to any one of claims 1 to 3, wherein a plurality of the polymer portions are formed so that cellulose nanofibers penetrate therethrough.   Each of the polymer portions monotonously increases to a first position in the continuous direction as a cross-sectional area in a cross section perpendicular to the continuous direction of the cellulose nanofibers advances in a direction from one end of the cellulose nanofiber toward the other end. A cross-sectional area increasing portion, and a cross-sectional area decreasing portion in which the cross-sectional area monotonously decreases as it proceeds from the first position or the second position existing on the other end side to the other end side toward the other end. The composite according to claim 4, which is formed by:   The composite according to any one of claims 1 to 3, wherein the polymer portion is spirally wound around cellulose nanofibers.   The composite according to any one of claims 1 to 6, wherein the polymer compound is polyvinyl alcohol.   A filler comprising the composite according to any one of claims 1 to 7.   A resin composition comprising a resin and the composite according to any one of claims 1 to 7. Cellulose nanofibers,
A polymer part formed of a polymer compound other than cellulose and bonded to at least a part of the surface of the cellulose nanofiber;
A method for producing a composite comprising
A solution contact step in which a solution of the polymer compound is contacted with cellulose nanofibers;
A precipitation step of reducing the amount of the polymer compound dissolved in the solution after the solution contact step, and depositing the polymer compound on the surface of the cellulose nanofiber;
A manufacturing method comprising:   The solution contact step includes a fiber dispersion preparation step for preparing a fiber dispersion in which cellulose nanofibers are dispersed in a dispersion medium, and a fiber for mixing the fiber dispersion prepared by the fiber dispersion preparation step and the polymer compound. The manufacturing method according to claim 10, comprising a dispersion mixing step. The dispersion medium is capable of dissolving the polymer compound;
The production method according to claim 11, wherein a solvent which is the same as the dispersion medium is mixed in the fiber dispersion liquid mixing step, and the polymer compound is dissolved in the solvent.   The production method according to claim 10, wherein the precipitation step is performed under stirring.   The manufacturing method according to any one of claims 10 to 12, wherein the precipitation step is performed without stirring.   The composite_body | complex which can be manufactured by the manufacturing method of any one of Claims 10 thru | or 14.