JP2018030966A - Fibrous cellulose-containing material - Google Patents

Abstract

An object of the present invention is to provide a fibrous cellulose-containing material capable of forming a highly transparent sheet from a re-dispersed liquid even after long-term storage.
The present invention relates to a fibrous cellulose-containing material containing fibrous cellulose having a fiber width of 1000 nm or less, and the content of fibrous cellulose is 5 mass relative to the total mass of the fibrous cellulose-containing material. %, The viscosity measured in condition 1 is 3000 mPa · s or more, the viscosity measured in condition 2a is ηB, and the viscosity measured in condition 2b is ηC, the value of ηB / ηC is 0.7 Larger fibrous cellulosic content.
[Selection figure] None

Description

  The present invention relates to a method for producing a fibrous cellulose-containing material.

  In recent years, materials that use reproducible natural fibers have attracted attention due to the substitution of petroleum resources and the growing environmental awareness. Among natural fibers, fibrous cellulose having a fiber diameter of 10 μm or more and 50 μm or less, in particular, fibrous cellulose (pulp) derived from wood has been widely used mainly as a paper product so far.

  As the fibrous cellulose, fine fibrous cellulose having a fiber diameter of 1 μm or less is also known. In recent years, a sheet composed of such fine fibrous cellulose and a composite sheet containing a fine fibrous cellulose-containing sheet and a resin have been developed. Further, since fine fibrous cellulose can exert a thickening action, it has been studied to use fine fibrous cellulose as a thickener for various applications.

  In the case of using fine fibrous cellulose as a thickener, for example, a liquid in which fine fibrous cellulose is dispersed is transported to a processing factory or the like. However, since the liquid in which fine fibrous cellulose is dispersed contains a large amount of dispersion medium, there is a problem that the cost for transportation is high. For this reason, in order to reduce transportation cost, it is desired to make the liquid in which fine fibrous cellulose is dispersed as concentrated as possible.

  For example, Patent Document 1 discloses a dry solid containing fine fibrous cellulose. In patent document 1, after adjusting the pH of the aqueous suspension of anion-modified cellulose nanofibers to 9 to 11, a dry solid of anion-modified cellulose nanofibers is obtained by dehydration and drying. Patent Document 2 discloses a process for producing cellulose nanofibers from a carboxy group-containing cellulose fiber, and a process for obtaining a gel by mixing cellulose nanofibers and a redispersion accelerator. . Here, the cellulose nanofibers are redispersed by mixing an organic liquid compound and a dispersant in the gel-like body, thereby obtaining a cellulose nanofiber dispersion.

Japanese Patent Laying-Open No. 2015-134873 JP 2014-118521 A

  It is preferable that concentrates such as dry solids and gels of fine fibrous cellulose have good redispersibility. For example, a fine fibrous cellulose-containing sheet may be formed using a re-dispersed liquid of fine fibrous cellulose. In this case, the fine fibrous cellulose-containing sheet is required to have transparency. Even after long-term storage of dry solids and concentrates of fine fibrous cellulose prior to redispersion, the fine fibrous cellulose-containing sheet is required to have high transparency. ing.

  Therefore, in order to solve such problems of the prior art, the present inventors re-dispersed even after long-term storage of a dry solid matter or concentrate of fine fibrous cellulose before being used as a redispersion liquid. The study was carried out for the purpose of realizing a cellulose-containing material capable of forming a highly transparent sheet from the liquid.

As a result of earnest studies to solve the above problems, the present inventors, in a fibrous cellulose-containing product containing fibrous cellulose having a fiber width of 1000 nm or less, when measuring the viscosity under specific conditions, It has been found that a highly transparent sheet can be formed from the redispersed liquid even after the fibrous cellulose-containing material has been stored for a long period of time by adjusting the viscosity under each condition to satisfy a predetermined condition.
Specifically, the present invention has the following configuration.

[1] A fibrous cellulose-containing material containing fibrous cellulose having a fiber width of 1000 nm or less, and the content of fibrous cellulose is 5% by mass or more based on the total mass of the fibrous cellulose-containing material, When the viscosity measured under Condition 1 is 3000 mPa · s or more, the viscosity measured under Condition 2a below is ηB, and the viscosity measured under Condition 2b below is ηC, the value of ηB / ηC is 0.7 Greater fibrous cellulose content;
(Condition 1)
The fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45 mass% or more and 0.7 mass% or less, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry A; After allowing A to stand at 23 ° C. for 24 hours, it is diluted so that the solid content concentration is 0.4 mass%, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry B; Stir for 2 minutes at a stirring speed of 2200 rpm using a revolutionary stirrer and let stand at 23 ° C. for 24 hours, then rotate for 3 minutes at 23 ° C. and 3 rpm to measure the viscosity using a B-type viscometer;
(Condition 2a)
Viscosity is measured in the same manner as described above (Condition 1) except that the fibrous cellulose-containing material that is allowed to stand at 23 ° C. for 240 hours is used;
(Condition 2b)
The fibrous cellulose-containing material that was allowed to stand at 23 ° C. for 240 hours was dispersed in water so that the solid content concentration was 0.45 mass% or more and 0.7 mass% or less, and the mixture was stirred for 5 minutes at a stirring speed of 12000 r · cm / min. Thus, slurry A ′ is obtained; the viscosity is measured in the same manner as in (Condition 1) except that slurry A ′ is used instead of slurry A.
[2] The fibrous cellulose-containing material according to [1], wherein the content of the metal component is 0.5% by mass or less based on the total mass of the fibrous cellulose-containing material.
[3] The fibrous cellulose-containing material according to [1] or [2], which is solid.
[4] When the viscosity measured under the following condition 3a is ηD and the viscosity measured under the following condition 3b is ηE, the value of ηD / ηE is any of [1] to [3] greater than 0.7 A fibrous cellulose-containing material according to claim 1;
(Condition 3a)
Viscosity is measured in the same manner as described above (Condition 1) except that the fibrous cellulose-containing material that is allowed to stand at 50 ° C. for 72 hours is used;
(Condition 3b)
Viscosity is measured in the same manner as described above (Condition 2b) except that a fibrous cellulose-containing material that has been allowed to stand at 50 ° C. for 72 hours is used.
[5] The fibrous cellulose-containing material according to any one of [1] to [4], further including a surfactant.
[6] The fibrous cellulose-containing product according to any one of [1] to [5], further including a water-soluble organic compound.

  According to the present invention, a fibrous cellulose-containing material capable of forming a highly transparent sheet from the redispersion liquid even after long-term storage is obtained.

FIG. 1 is a graph showing the relationship between the amount of NaOH dripped with respect to the fiber material and the electrical conductivity.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

(Fibrous cellulose-containing material)
The present invention relates to a fibrous cellulose-containing material containing fibrous cellulose having a fiber width of 1000 nm or less (hereinafter also referred to as fine fibrous cellulose). The content of fibrous cellulose in the fibrous cellulose-containing material is 5% by mass or more with respect to the total mass of the fibrous cellulose-containing material. In the fibrous cellulose-containing material of the present invention, the viscosity measured under the following condition 1 is 3000 mPa · s or more, the viscosity measured under the following condition 2a is ηB, and the viscosity measured under the following condition 2b is ηC. In this case, the value of ηB / ηC is larger than 0.7.

Here, Condition 1, Conditions 2a and 2b are as follows.
(Condition 1)
The fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45 mass% or more and 0.7 mass% or less, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry A; After allowing A to stand at 23 ° C. for 24 hours, it is diluted so that the solid content concentration is 0.4 mass%, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry B; The mixture is stirred for 2 minutes at a stirring speed of 2200 rpm using a revolutionary stirrer and allowed to stand at 23 ° C. for 24 hours, and then rotated at 23 ° C. for 3 minutes at 3 rpm with a B-type viscometer to measure the viscosity.
(Condition 2a)
The viscosity is measured in the same manner as above (Condition 1) except that a fibrous cellulose-containing material that is allowed to stand at 23 ° C. for 240 hours is used.
(Condition 2b)
The fibrous cellulose-containing material that was allowed to stand at 23 ° C. for 240 hours was dispersed in water so that the solid content concentration was 0.45 mass% or more and 0.7 mass% or less, and the mixture was stirred for 5 minutes at a stirring speed of 12000 r · cm / min. Thus, slurry A ′ is obtained; the viscosity is measured in the same manner as in (Condition 1) except that slurry A ′ is used instead of slurry A.

  Since the fibrous cellulose-containing material of the present invention has the above-described configuration, it can exhibit good redispersibility, and can exhibit excellent thickening after being dispersed in a solvent such as water. Specifically, the initial viscosity of the re-dispersion of the fibrous cellulose-containing material may be 3000 mPa · s or more, preferably 5000 mPa · s or more, more preferably 6000 mPa · s or more, and 10000 mPa · s. More preferably, it is s or more. The initial viscosity of the re-dispersion of the fibrous cellulose-containing material is measured according to the condition 1 described above. First, the fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45% by mass or more and 0.7% by mass or less, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry A. . In this case, the fibrous cellulose-containing material is used after preparation and at room temperature for which 20 hours have not elapsed. And this slurry A is left still at 23 degreeC for 24 hours, Then, it dilutes so that solid content concentration may be 0.4 mass%, and it stirs for 5 minutes with the stirring speed of 2250 r * cm / min, and obtains the slurry B. Slurry B is put into a glass screw bottle with a capacity of 50 mL, and stirred for 2 minutes at a stirring speed of 2200 rpm using a rotating and rotating stirrer. In the stirring using the rotation / revolution stirrer, defoaming treatment is performed. Thereafter, the mixture is allowed to stand at 23 ° C. for 24 hours, and is rotated at 23 ° C. for 3 minutes at 3 rpm using a B-type viscometer, and the viscosity is measured. In addition, a disperser (stirring TK Robotics, manufactured by Tokushu Kika Kogyo Co., Ltd., using a stirring blade with a radius of 1.5 cm) is used for stirring at a stirring speed of 2250 r · cm / min in the step of obtaining slurry A and slurry B. be able to. In addition, as the revolution / revolution stirrer, for example, a revolution / revolution supermixer can be used, and ARE-250 manufactured by Shinky Corporation can be exemplified. And as a B-type viscometer, the BLOOKFIELD company make and analog viscometer T-LVT can be used.

The fibrous cellulose-containing material of the present invention can exhibit excellent thickening after redispersion even after long-term storage. That is, the fibrous cellulose-containing material of the present invention is excellent in long-term storage properties, and can exhibit a certain viscosity or more even after long-term storage. The viscosity of the redispersion liquid after long-term storage can be measured under condition 2a. In condition 2a, first, the fibrous cellulose-containing material is allowed to stand at 23 ° C. for 240 hours. Thereafter, the fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45 mass% or more and 0.7 mass% or less, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry A. . After this slurry A is allowed to stand at 23 ° C. for 24 hours, it is diluted so that the solid content concentration becomes 0.4 mass%, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry B. Slurry B is put into a glass screw bottle with a capacity of 50 mL, and stirred for 2 minutes at a stirring speed of 2200 rpm using a rotating and rotating stirrer. In the stirring using the rotation / revolution stirrer, defoaming treatment is performed. Thereafter, the mixture is allowed to stand at 23 ° C. for 24 hours, and is rotated at 23 ° C. for 3 minutes at 3 rpm using a B-type viscometer, and the viscosity is measured. In addition, about the stirring apparatus and a viscometer, the thing similar to the conditions 1 can be used.
The viscosity of the redispersion liquid measured under Condition 2a is preferably 3000 mPa · s or more, more preferably 5000 mPa · s or more, further preferably 8000 mPa · s or more, and 9000 mPa · s or more. It is particularly preferred.

Further, the fibrous cellulose-containing material of the present invention is characterized in that there is little difference in viscosity due to the strength of stirring force after long-term storage. Specifically, when the viscosity measured under condition 2a is ηB and the viscosity measured under condition 2b is ηC, the value of ηB / ηC only needs to be greater than 0.7 and should be 0.8 or more. Preferably, it is 0.9 or more, more preferably 1.0 or more. Here, the viscosity ηB measured under the condition 2a is a viscosity obtained by performing normal stirring on the re-dispersed liquid after long-term storage and then measured, and the viscosity ηC measured under the condition 2b is applied to the re-dispersed liquid after long-term storage. Viscosity measured after strong stirring. In condition 2b, first, the fibrous cellulose-containing material is allowed to stand at 23 ° C. for 240 hours. Thereafter, the fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45% by mass or more and 0.7% by mass or less, and stirred at a stirring speed of 12000 r · cm / min for 5 minutes to obtain slurry A ′. obtain. This slurry A ′ is allowed to stand at 23 ° C. for 24 hours, then diluted so that the solid content concentration becomes 0.4 mass%, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry B ′. Slurry B ′ is placed in a 50 mL glass screw bottle and stirred for 2 minutes at a stirring speed of 2200 rpm using a rotating and rotating stirrer. In the stirring using the rotation / revolution stirrer, defoaming treatment is performed. Thereafter, the mixture is allowed to stand at 23 ° C. for 24 hours, and is rotated at 23 ° C. for 3 minutes at 3 rpm using a B-type viscometer, and the viscosity is measured. In addition, about the stirring apparatus and a viscometer, the thing similar to the conditions 1 can be used.
The viscosity of the redispersion liquid measured under Condition 2b is preferably 3000 mPa · s or more, more preferably 5000 mPa · s or more, and further preferably 8500 mPa · s or more.

  In the fibrous cellulose-containing material of the present invention, the redispersion liquid was measured under condition 2b, with the viscosity of the redispersion liquid measured under condition 1 being 3000 mPa · s or more and the viscosity ηB of the redispersion liquid measured under condition 2a. By making the numerical value (ηB / ηC) obtained by dividing by the viscosity ηC of greater than 0.7, a highly transparent sheet can be formed from the redispersed liquid even after long-term storage. In addition, the present invention has succeeded in producing a fibrous cellulose-containing material that satisfies all the above conditions, and has also found for the first time the relationship between such viscosity conditions and sheet transparency. In addition, the fibrous cellulose-containing material that satisfies a specific viscosity condition is, for example, controlling the type and amount of additives added to the fibrous cellulose-containing material, or appropriately controlling the manufacturing process of the fibrous cellulose-containing material. Can be obtained at

  In the fibrous cellulose-containing material of the present invention, when the viscosity measured under the following condition 3a is ηD and the viscosity measured under the following condition 3b is ηE, the value of ηD / ηE is greater than 0.7. Is more preferable, 0.8 or more is more preferable, and 1.0 or more is further preferable.

Here, the conditions 3a and 3b are as follows.
(Condition 3a)
The viscosity is measured in the same manner as above (Condition 1) except that the fibrous cellulose-containing material that is allowed to stand at 50 ° C. for 72 hours is used.
(Condition 3b)
Viscosity is measured in the same manner as described above (Condition 2b) except that a fibrous cellulose-containing material that is allowed to stand at 50 ° C. for 72 hours is used.

In condition 3a, first, the fibrous cellulose-containing material is allowed to stand at 50 ° C. for 72 hours. Thereafter, the fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45 mass% or more and 0.7 mass% or less, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry A. . After this slurry A is allowed to stand at 23 ° C. for 24 hours, it is diluted so that the solid content concentration becomes 0.4 mass%, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry B. Slurry B is put into a glass screw bottle with a capacity of 50 mL, and stirred for 2 minutes at a stirring speed of 2200 rpm using a rotating and rotating stirrer. In the stirring using the rotation / revolution stirrer, defoaming treatment is performed. Thereafter, the mixture is allowed to stand at 23 ° C. for 24 hours, and is rotated at 23 ° C. for 3 minutes at 3 rpm using a B-type viscometer, and the viscosity is measured. In addition, about the stirring apparatus and a viscometer, the thing similar to the conditions 1 can be used.
The viscosity of the redispersion liquid measured under Condition 3a is preferably 2000 mPa · s or more, more preferably 3000 mPa · s or more, further preferably 4000 mPa · s or more, and 5000 mPa · s or more. It is particularly preferred.

In condition 3b, first, the fibrous cellulose-containing material is allowed to stand at 50 ° C. for 72 hours. Thereafter, the fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45% by mass or more and 0.7% by mass or less, and stirred at a stirring speed of 12000 r · cm / min for 5 minutes to obtain slurry A ′. obtain. This slurry A ′ is allowed to stand at 23 ° C. for 24 hours, then diluted so that the solid content concentration becomes 0.4 mass%, and stirred at a stirring speed of 2250 r · cm / min for 5 minutes to obtain slurry B ′. Slurry B ′ is placed in a 50 mL glass screw bottle and stirred for 2 minutes at a stirring speed of 2200 rpm using a rotating and rotating stirrer. In the stirring using the rotation / revolution stirrer, defoaming treatment is performed. Thereafter, the mixture is allowed to stand at 23 ° C. for 24 hours, and is rotated at 23 ° C. for 3 minutes at 3 rpm using a B-type viscometer, and the viscosity is measured. In addition, about the stirring apparatus and a viscometer, the thing similar to the conditions 1 can be used.
The viscosity of the redispersion liquid measured under Condition 3b is preferably 3000 mPa · s or more, more preferably 5000 mPa · s or more, further preferably 6000 mPa · s or more, and 8000 mPa · s or more. It is particularly preferred.

  Even in the measurement under the conditions 3a and 3b, by controlling the value of ηD / ηE within the above range, it becomes easy to form a highly transparent sheet from the redispersion liquid even after long-term storage.

  The form of the fibrous cellulose-containing material is not particularly limited, and can be present in various forms such as a solid form, a gel form, and a liquid form. Among these, the fibrous cellulose-containing material is preferably solid or gel, and more preferably solid. Further, the fibrous cellulose-containing material is more preferably a granular material. Here, the granular material is a powdery and / or granular substance. The powdery substance is smaller than the granular substance. In general, a powdery substance refers to fine particles having a particle diameter of 1 nm to less than 0.1 mm, and a granular substance refers to particles having a particle diameter of 0.1 mm to 10 mm. In a broad sense, it can be said that a gel is also a solid form, and may be classified as a solid.

  The fibrous cellulose-containing material of the present invention contains 5% by mass or more of fine fibrous cellulose. For this reason, the fibrous cellulose-containing material can also be called a fine fibrous cellulose concentrate or a fine fibrous cellulose aggregate. The content of fibrous cellulose should just be 5 mass% or more with respect to the total mass of a fibrous cellulose containing material, It is more preferable that it is 7.5 mass% or more, It is further more preferable that it is 10 mass% or more. preferable. Moreover, the upper limit of content of fibrous cellulose is not specifically limited, For example, it can be 95 mass%. In the fibrous cellulose-containing material of the present invention, fibrous cellulose is present at a high concentration and is in a concentrated form, so that storage costs and transportation costs can be reduced. In addition, for example, when used as a thickener or a raw material for compounding, the amount of water brought in can be reduced. Furthermore, the stability of the fibrous cellulose in the fibrous cellulose-containing material can be increased by setting the content of the fibrous cellulose-containing material within the above range.

  In addition, when content of fibrous cellulose is the range of 5 mass% or more and less than 10 mass% with respect to the total mass of fibrous cellulose containing material, generally fibrous cellulose containing material is a gel form. . Moreover, when content of fibrous cellulose is 10 mass% or more with respect to the total mass of fibrous cellulose containing material, fibrous cellulose containing material is solid.

  When the fibrous cellulose-containing material of the present invention is made into a slurry having a solid content concentration of 0.5% by mass, the pH of the slurry is preferably 4 or more, more preferably 4.5 or more. Is more preferably 0.0 or more, and particularly preferably 6.0 or more. Further, the pH of the slurry having a solid content concentration of 0.5% by mass is preferably 13 or less, more preferably 12 or less, and further preferably 11 or less. By setting the pH of the slurry having a solid content concentration of 0.5% by mass within the above range, the long-term storage stability of the fibrous cellulose-containing material can be further improved.

  The pH of the slurry with a solid content concentration of 0.5% by mass is obtained by adding a fine fibrous cellulose-containing material to ion-exchanged water to obtain a slurry with a solid content concentration of 0.5% by mass, and then stirring with a magnetic stirrer. Measure after the whole is mixed. The pH displayed on the apparatus is read after 5 minutes or more from the start of stirring by the magnetic stirrer. Moreover, the temperature at the time of measurement was 23 degreeC. As the pH measuring device, a known measuring device can be used.

The ratio of the amount of coarse cellulose fibers contained in the fibrous cellulose-containing product of the present invention is not particularly limited, but is preferably less than 50%. The amount of coarse cellulose fibers is more preferably less than 30%, and even more preferably less than 10%. Here, the amount of coarse cellulose fibers is measured by the following method.
First, ion-exchanged water is added to the slurry of fine fibrous cellulose to adjust the fiber solid content concentration to 0.2% by mass. Next, the mixture is centrifuged under the condition of 12000 G × 10 min, and the resulting supernatant is recovered. Then, the solid content concentration of the supernatant is measured. And the ratio of a coarse cellulose fiber is computed by a following formula.
Ratio of coarse cellulose fiber (%) = 100− (solid content concentration of supernatant / 0.2% by mass × 100)

(Fibrous cellulose)
The fibrous cellulose-containing material of the present invention contains fibrous cellulose (fine fibrous cellulose) having a fiber width of 1000 nm or less. The fine fibrous cellulose is preferably a fiber having an ionic functional group. In this case, the ionic functional group is preferably an anionic functional group (hereinafter also referred to as an anionic group). Examples of the anionic group include a phosphate group or a substituent derived from a phosphate group (sometimes simply referred to as a phosphate group), a carboxyl group or a substituent derived from a carboxyl group (sometimes simply referred to as a carboxyl group), In addition, it is preferably at least one selected from a sulfone group or a substituent derived from a sulfone group (sometimes simply referred to as a sulfone group), and at least one selected from a phosphate group and a carboxyl group Is more preferable, and a phosphate group is particularly preferable. In addition, in this specification, the fibrous cellulose which has a phosphoric acid group may be called a phosphorylated fine fibrous cellulose.

  Although it does not specifically limit as a fibrous cellulose raw material for obtaining a fine fibrous cellulose, It is preferable to use a pulp from the point of being easy to acquire and cheap. Examples of the pulp include wood pulp, non-wood pulp, and deinked pulp. Examples of wood pulp include hardwood kraft pulp (LBKP), softwood kraft pulp (NBKP), sulfite pulp (SP), dissolved pulp (DP), soda pulp (AP), unbleached kraft pulp (UKP), oxygen bleached craft Chemical pulps such as pulp (OKP) are listed. Moreover, semi-chemical pulps such as semi-chemical pulp (SCP) and chemi-ground wood pulp (CGP), mechanical pulps such as ground wood pulp (GP), thermomechanical pulp (TMP, BCTMP) and the like can be mentioned, but are not particularly limited. Non-wood pulp includes cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw and bagasse, cellulose isolated from sea squirts and seaweed, chitin, chitosan, etc., but is not particularly limited. . The deinking pulp includes deinking pulp made from waste paper, but is not particularly limited. The pulp of this embodiment may be used alone or in combination of two or more. Among the above pulps, wood pulp containing cellulose and deinked pulp are preferable in terms of availability. Among wood pulps, chemical pulp has a large cellulose ratio, so the yield of fine fibrous cellulose during fiber refinement (defibration) is high, and the degradation of cellulose in the pulp is small, and the fineness of long fibers with a large axial ratio is high. It is preferable at the point from which fibrous cellulose is obtained. Of these, kraft pulp and sulfite pulp are most preferably selected. Sheets containing long fibrous fine fibrous cellulose having a large axial ratio tend to provide high strength.

  The average fiber width of the fine fibrous cellulose is 1000 nm or less as observed with an electron microscope. The average fiber width is preferably 2 nm or more and 1000 nm or less, more preferably 2 nm or more and 100 nm or less, more preferably 2 nm or more and 50 nm or less, and further preferably 2 nm or more and 10 nm or less, but is not particularly limited. When the average fiber width of the fine fibrous cellulose is less than 2 nm, the physical properties (strength, rigidity, dimensional stability) as the fine fibrous cellulose tend to be difficult to be expressed because the cellulose molecules are dissolved in water. . The fine fibrous cellulose is monofilamentous cellulose having a fiber width of 1000 nm or less, for example.

  Measurement of the fiber width of the fine fibrous cellulose by electron microscope observation is performed as follows. An aqueous suspension of fine fibrous cellulose having a concentration of 0.05% by mass or more and 0.1% by mass or less is prepared, and the suspension is cast on a carbon film-coated grid subjected to a hydrophilic treatment to prepare a sample for TEM observation. To do. When a wide fiber is included, an SEM image of the surface cast on glass may be observed. Observation with an electron microscope image is performed at a magnification of 1000 times, 5000 times, 10000 times, or 50000 times depending on the width of the constituent fibers. However, the sample, observation conditions, and magnification are adjusted to satisfy the following conditions.

(1) One straight line X is drawn at an arbitrary location in the observation image, and 20 or more fibers intersect the straight line X.
(2) A straight line Y perpendicular to the straight line is drawn in the same image, and 20 or more fibers intersect the straight line Y.

  The width of the fiber that intersects with the straight line X and the straight line Y is visually read from the observation image that satisfies the above conditions. In this way, at least three sets of images of the surface portion that do not overlap each other are observed, and the width of the fiber intersecting with the straight line X and the straight line Y is read for each image. Thus, at least 20 × 2 × 3 = 120 fiber widths are read. The average fiber width (sometimes simply referred to as “fiber width”) of fine fibrous cellulose is an average value of the fiber widths read in this way.

  The fiber length of the fine fibrous cellulose is not particularly limited, but is preferably 0.1 μm or more and 1000 μm or less, more preferably 0.1 μm or more and 800 μm or less, and particularly preferably 0.1 μm or more and 600 μm or less. By making the fiber length within the above range, the destruction of the crystalline region of the fine fibrous cellulose can be suppressed, and the slurry viscosity of the fine fibrous cellulose can be made an appropriate range. Note that the fiber length of the fine fibrous cellulose can be determined by image analysis using TEM, SEM, or AFM.

The fine fibrous cellulose preferably has an I-type crystal structure. Here, the fact that the fine fibrous cellulose has a type I crystal structure can be identified in a diffraction profile obtained from a wide-angle X-ray diffraction photograph using CuKα (λ = 1.5418Å) monochromatized with graphite. Specifically, it can be identified by having typical peaks at two positions of 2θ = 14 ° to 17 ° and 2θ = 22 ° to 23 °.
The proportion of the I-type crystal structure in the fine fibrous cellulose is preferably 30% or more, more preferably 50% or more, and further preferably 70% or more. In this case, further superior performance can be expected in terms of heat resistance and low linear thermal expansion coefficient. The degree of crystallinity is obtained by measuring an X-ray diffraction profile and determining the crystallinity by a conventional method (Seagal et al., Textile Research Journal, 29, 786, 1959).

The fine fibrous cellulose preferably has a phosphate group or a substituent derived from a phosphate group. The phosphoric acid group is a divalent functional group equivalent to the phosphoric acid obtained by removing the hydroxyl group. Specifically, it is a group represented by —PO ₃ H ₂ . Substituents derived from phosphoric acid groups include substituents such as groups obtained by polycondensation of phosphoric acid groups, salts of phosphoric acid groups, and phosphoric acid ester groups. It may be a group.

In the present invention, the phosphate group or the substituent derived from the phosphate group may be a substituent represented by the following formula (1).

In formula (1), a, b, m and n each independently represent an integer (where a = b × m); α ⁿ (n = 1 to n) and α ′ are each independently R or OR is represented. R represents a hydrogen atom, a saturated-linear hydrocarbon group, a saturated-branched hydrocarbon group, a saturated-cyclic hydrocarbon group, an unsaturated-linear hydrocarbon group, an unsaturated-branched hydrocarbon group. , An aromatic group, or a derivative group thereof; β is a monovalent or higher cation composed of an organic substance or an inorganic substance.

<Phosphate group introduction process>
In the phosphate group introduction step, the fiber raw material containing cellulose is reacted with at least one selected from a compound having a phosphate group and a salt thereof (hereinafter referred to as “phosphorylation reagent” or “compound A”). Can be performed. Such a phosphorylating reagent may be mixed in a powder or aqueous solution with a dry or wet fiber raw material. As another example, a phosphorylating reagent powder or an aqueous solution may be added to the fiber raw material slurry.

  The phosphoric acid group introduction step can be performed by reacting at least one selected from a compound having a phosphoric acid group and a salt thereof (a phosphorylating reagent or compound A) with a fiber raw material containing cellulose. This reaction may be carried out in the presence of at least one selected from urea and derivatives thereof (hereinafter referred to as “compound B”).

  As an example of a method for causing Compound A to act on a fiber raw material in the presence of Compound B, a method of mixing a powder or an aqueous solution of Compound A and Compound B with a dry or wet fiber raw material can be mentioned. Another example is a method in which powders and aqueous solutions of Compound A and Compound B are added to the fiber raw material slurry. Of these, since the uniformity of the reaction is high, a method of adding an aqueous solution of Compound A and Compound B to a dry fiber material, or a powder or an aqueous solution of Compound A and Compound B to a wet fiber material The method is preferred. Moreover, the compound A and the compound B may be added simultaneously, or may be added separately. Moreover, you may add the compound A and the compound B first used for reaction as aqueous solution, and remove an excess chemical | medical solution by pressing. The form of the fiber raw material is preferably cotton or thin sheet, but is not particularly limited.

Compound A used in this embodiment is at least one selected from a compound having a phosphate group and a salt thereof.
Examples of the compound having a phosphate group include, but are not limited to, phosphoric acid, lithium salt of phosphoric acid, sodium salt of phosphoric acid, potassium salt of phosphoric acid, ammonium salt of phosphoric acid, and the like. Examples of the lithium salt of phosphoric acid include lithium dihydrogen phosphate, dilithium hydrogen phosphate, trilithium phosphate, lithium pyrophosphate, and lithium polyphosphate. Examples of the sodium salt of phosphoric acid include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, and sodium polyphosphate. Examples of the potassium salt of phosphoric acid include potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, and potassium polyphosphate. Examples of the ammonium salt of phosphoric acid include ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium polyphosphate.

  Among these, phosphoric acid and phosphoric acid are introduced efficiently from the viewpoint that the introduction efficiency of phosphate groups is high, the fibrillation efficiency is easily improved in the fibrillation process described later, the cost is low, and the industrial application is easy. Sodium salt, potassium salt of phosphoric acid, and ammonium salt of phosphoric acid are preferable. Sodium dihydrogen phosphate or disodium hydrogen phosphate is more preferable.

  In addition, compound A is preferably used as an aqueous solution because the uniformity of the reaction is increased and the efficiency of introduction of phosphate groups is increased. The pH of the aqueous solution of Compound A is not particularly limited, but is preferably 7 or less because the efficiency of introduction of phosphate groups is increased, and more preferably pH 3 or more and pH 7 or less from the viewpoint of suppressing the hydrolysis of pulp fibers. The pH of the aqueous solution of Compound A may be adjusted by, for example, using a phosphoric acid group-containing compound that exhibits acidity and an alkalinity, and changing the amount ratio thereof. You may adjust pH of the aqueous solution of the compound A by adding an inorganic alkali or an organic alkali to the thing which shows acidity among the compounds which have a phosphoric acid group.

  The amount of compound A added to the fiber raw material is not particularly limited, but when the amount of compound A added is converted to phosphorus atomic weight, the amount of phosphorus atom added to the fiber raw material (absolute dry mass) is 0.5 mass% to 100 mass%. Or less, more preferably 1% by mass or more and 50% by mass or less, and most preferably 2% by mass or more and 30% by mass or less. If the amount of phosphorus atoms added to the fiber raw material is within the above range, the yield of fine fibrous cellulose can be further improved. Moreover, the cost of the compound A to be used can be suppressed while improving phosphorylation efficiency by making the addition amount of the phosphorus atom with respect to a fiber raw material into 100 mass% or less.

  Examples of the compound B used in this embodiment include urea, biuret, 1-phenylurea, 1-benzylurea, 1-methylurea, 1-ethylurea and the like.

  Compound B is preferably used as an aqueous solution in the same manner as Compound A. Moreover, since the uniformity of reaction increases, it is preferable to use the aqueous solution in which both compound A and compound B are dissolved. The amount of Compound B added to the fiber raw material (absolute dry mass) is preferably 1% by mass or more and 500% by mass or less, more preferably 10% by mass or more and 400% by mass or less, and 100% by mass or more and 350% by mass or less. More preferably, it is more preferably 150% by mass or more and 300% by mass or less.

  In addition to Compound A and Compound B, amides or amines may be included in the reaction system. Examples of amides include formamide, dimethylformamide, acetamide, dimethylacetamide and the like. Examples of amines include methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine, and the like. Among these, triethylamine is known to work as a good reaction catalyst.

  In the phosphoric acid group introduction step, it is preferable to perform a heat treatment. As the heat treatment temperature, it is preferable to select a temperature at which a phosphate group can be efficiently introduced while suppressing thermal decomposition and hydrolysis reaction of the fiber. Specifically, it is preferably 50 ° C. or higher and 300 ° C. or lower, more preferably 100 ° C. or higher and 250 ° C. or lower, and further preferably 130 ° C. or higher and 200 ° C. or lower. Moreover, you may use a vacuum dryer, an infrared heating apparatus, and a microwave heating apparatus for a heating.

  During the heat treatment, while water is contained in the fiber raw material slurry to which compound A is added, if the time for allowing the fiber raw material to stand still becomes long, the compound A dissolved with water molecules moves to the fiber raw material surface with drying. To do. Therefore, the concentration of the compound A in the fiber raw material may be uneven, and the introduction of phosphate groups on the fiber surface may not proceed uniformly. In order to suppress the occurrence of unevenness in concentration of Compound A in the fiber material due to drying, a very thin sheet-like fiber material is used, or the fiber material and Compound A are kneaded or stirred with a kneader or the like and dried by heating or reduced pressure. The method should be taken.

  The heating device used for the heat treatment is preferably a device that can always discharge the moisture retained by the slurry and the moisture generated by the addition reaction of the fibers such as phosphate groups to the hydroxyl group of the fiber, such as a blower oven. Etc. are preferred. If water in the system is always discharged, the hydrolysis reaction of the phosphate ester bond, which is the reverse reaction of the esterification, can be suppressed, and the acid hydrolysis of the sugar chain in the fiber can also be suppressed. A fine fiber having a high axial ratio can be obtained.

  The heat treatment time is also affected by the heating temperature, but it is preferably 1 second or more and 300 minutes or less, preferably 1 second or more and 1000 seconds or less after moisture is substantially removed from the fiber raw material slurry. Preferably, it is 10 seconds or more and 800 seconds or less. In the present invention, the amount of phosphate groups introduced can be within a preferred range by setting the heating temperature and the heating time to appropriate ranges.

  The amount of phosphate group introduced is preferably 0.1 mmol / g or more and 3.65 mmol / g or less, more preferably 0.14 mmol / g or more and 3.5 mmol / g or less per 1 g (mass) of fine fibrous cellulose. 0.2 mmol / g or more and 3.2 mmol / g or less is more preferable, 0.4 mmol / g or more and 3.0 mmol / g or less is particularly preferable, and most preferably 0.6 mmol / g or more and 2.5 mmol / g or less. . By making the introduction amount of the phosphoric acid group within the above range, the fiber raw material can be easily refined, and the stability of the fine fibrous cellulose can be enhanced. In addition, by making the introduction amount of phosphoric acid groups within the above range, it is possible to leave hydrogen bonds between fine fibrous celluloses while being easy to make fine, and when used as a sheet, it has good strength Expression can be expected.

  The amount of phosphate group introduced into the fiber material can be measured by a conductivity titration method. Specifically, by performing the defibration process step, after treating the resulting fine fibrous cellulose-containing slurry with an ion exchange resin, by determining the change in electrical conductivity while adding an aqueous sodium hydroxide solution, The amount introduced can be measured.

  In conductivity titration, when alkali is added, the curve shown in FIG. 1 is given. Initially, the electrical conductivity rapidly decreases (hereinafter referred to as “first region”). Thereafter, the conductivity starts to increase slightly (hereinafter referred to as “second region”). Thereafter, the conductivity increment increases (hereinafter referred to as “third region”). That is, three areas appear. Among these, the amount of alkali required in the first region is equal to the amount of strongly acidic groups in the slurry used for titration, and the amount of alkali required in the second region is the amount of weakly acidic groups in the slurry used for titration. Will be equal. When the phosphoric acid group undergoes condensation, apparently weakly acidic groups are lost, and the amount of alkali required in the second region is reduced compared to the amount of alkali required in the first region. On the other hand, the amount of strongly acidic groups coincides with the amount of phosphorus atoms regardless of the presence or absence of condensation, so that the amount of phosphate groups introduced (or the amount of phosphate groups) or the amount of substituent introduced (or the amount of substituents) is simply When said, it represents the amount of strongly acidic group. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 is divided by the solid content (g) in the titration target slurry to obtain the substituent introduction amount (mmol / g).

  The phosphate group introduction step may be performed at least once, but may be repeated a plurality of times. In this case, more phosphoric acid groups are introduced, which is preferable.

<Introduction of carboxyl group>
In the present invention, when the fine fibrous cellulose has a carboxyl group, for example, the fiber raw material is subjected to an oxidation treatment such as a TEMPO oxidation treatment, a compound having a carboxylic acid-derived group, a derivative thereof, or an acid thereof. A carboxyl group can be introduced by treatment with an anhydride or a derivative thereof.

  The compound having a carboxyl group is not particularly limited, and examples thereof include dicarboxylic acid compounds such as maleic acid, succinic acid, phthalic acid, fumaric acid, glutaric acid, adipic acid and itaconic acid, and tricarboxylic acid compounds such as citric acid and aconitic acid. .

  The acid anhydride of the compound having a carboxyl group is not particularly limited, but examples thereof include acid anhydrides of dicarboxylic acid compounds such as maleic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, adipic anhydride, and itaconic anhydride. It is done.

  Although it does not specifically limit as a derivative of the compound which has a carboxyl group, The derivative of the acid anhydride of the compound which has a carboxyl group and the acid anhydride imidation of a compound which has a carboxyl group are mentioned. Although it does not specifically limit as an acid anhydride imidation thing of a compound which has a carboxyl group, Imidation thing of dicarboxylic acid compounds, such as maleimide, succinic acid imide, and phthalic acid imide, is mentioned.

  The acid anhydride derivative of the compound having a carboxyl group is not particularly limited. For example, at least some of the hydrogen atoms of the acid anhydride of the compound having a carboxyl group, such as dimethylmaleic anhydride, diethylmaleic anhydride, diphenylmaleic anhydride, etc. are substituted (for example, alkyl group, phenyl group, etc. ) Are substituted.

  The amount of carboxyl group introduced is preferably 0.1 mmol / g or more and 3.65 mmol / g or less, more preferably 0.14 mmol / g or more and 3.5 mmol / g or less, per 1 g (mass) of fine fibrous cellulose. It is more preferably 0.2 mmol / g or more and 3.2 mmol / g or less, particularly preferably 0.4 mmol / g or more and 3.0 mmol / g or less, and most preferably 0.6 mmol / g or more and 2.5 mmol / g or less.

<Alkali treatment>
When manufacturing a fine fibrous cellulose, you may perform an alkali treatment between an ionic functional group introduction | transduction process and the defibration process mentioned later. Although it does not specifically limit as a method of an alkali treatment, For example, the method of immersing a functional group introduction | transduction fiber in an alkaline solution is mentioned.
The alkali compound contained in the alkali solution is not particularly limited, but may be an inorganic alkali compound or an organic alkali compound. The solvent in the alkaline solution may be either water or an organic solvent. The solvent is preferably a polar solvent (polar organic solvent such as water or alcohol), and more preferably an aqueous solvent containing at least water.
Of the alkaline solutions, a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution is particularly preferred because of its high versatility.

Although the temperature of the alkali solution in an alkali treatment process is not specifically limited, 5 to 80 degreeC is preferable and 10 to 60 degreeC is more preferable.
The immersion time in the alkaline solution in the alkali treatment step is not particularly limited, but is preferably 5 minutes or longer and 30 minutes or shorter, and more preferably 10 minutes or longer and 20 minutes or shorter.
Although the usage-amount of the alkaline solution in an alkali treatment is not specifically limited, It is preferable that it is 100 mass% or more and 100,000 mass% or less with respect to the absolute dry mass of a phosphate group introduction | transduction fiber, and is 1000 mass% or more and 10000 mass% or less. It is more preferable.

  In order to reduce the amount of the alkali solution used in the alkali treatment step, the functional group-introduced fiber may be washed with water or an organic solvent before the alkali treatment step. After the alkali treatment, in order to improve the handleability, it is preferable to wash the alkali-treated functional group-introduced fiber with water or an organic solvent before the defibrating treatment step.

<Defibration processing>
The ionic functional group-introduced fiber is defibrated in the defibrating process. In the defibrating process, the fiber is usually defibrated using a defibrating apparatus to obtain a fine fibrous cellulose-containing slurry, but the processing apparatus and the processing method are not particularly limited.
As the defibrating apparatus, a high-speed defibrator, a grinder (stone mill type pulverizer), a high-pressure homogenizer, an ultra-high pressure homogenizer, a high-pressure collision type pulverizer, a ball mill, a bead mill, or the like can be used. Alternatively, as a defibrating apparatus, a device for wet grinding such as a disk type refiner, a conical refiner, a twin-screw kneader, a vibration mill, a homomixer under high-speed rotation, an ultrasonic disperser, or a beater should be used. You can also. The defibrating apparatus is not limited to the above. Preferable defibrating treatment methods include a high-speed defibrator, a high-pressure homogenizer, and an ultra-high pressure homogenizer that are less affected by the grinding media and less worried about contamination.

  When using an ultra-high pressure homogenizer, the pressure during the defibrating treatment is preferably 150 MPa or more, and more preferably 200 MPa or more. Moreover, it is preferable that the pressure at the time of a fibrillation process is 500 Mpa or less. Further, the number of treatments is preferably 2 times or more, and more preferably 3 times or more.

  In the defibrating process, it is preferable to dilute the fiber raw material with water and an organic solvent alone or in combination to form a slurry, but there is no particular limitation. As the dispersion medium, in addition to water, a polar organic solvent can be used. Preferable polar organic solvents include alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like, but are not particularly limited. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol. Examples of ketones include acetone and methyl ethyl ketone (MEK). Examples of ethers include diethyl ether and tetrahydrofuran (THF). The dispersion medium may be one type or two or more types. Further, the dispersion medium may contain a solid content other than the fiber raw material, such as urea having hydrogen bonding property.

  The fine fibrous cellulose may be obtained by once concentrating and / or drying the fine fibrous cellulose-containing slurry obtained by the defibrating treatment and then performing the defibrating treatment again. In this case, the concentration and drying methods are not particularly limited, and examples thereof include a method of adding a concentrating agent to a slurry containing fine fibrous cellulose, a generally used dehydrator, a press, and a method using a dryer. Moreover, a well-known method, for example, the method described in WO2014 / 024876, WO2012 / 107642, and WO2013 / 121086 can be used. Moreover, it can concentrate and dry by making a fine fibrous cellulose containing slurry into a sheet | seat, a fibrillation process can be performed to this sheet | seat, and a fine fibrous cellulose containing slurry can also be obtained again.

  The equipment used when the fine fibrous cellulose-containing slurry is concentrated and / or dried and then defibrated (pulverized) again includes high-speed defibrator, grinder (stone mill grinder), high-pressure homogenizer, and ultra-high pressure homogenizer. , High pressure collision type pulverizer, ball mill, bead mill, disk type refiner, conical refiner, biaxial kneader, vibration mill, homomixer under high speed rotation, ultrasonic disperser, beater, etc. There is no particular limitation.

(Metal component)
The fibrous cellulose-containing material of the present invention may contain a bivalent or higher-valent metal component. The divalent or higher metal component is preferably a component added as a metal salt in the aggregation step of the production process of the fibrous cellulose-containing material. Since such a metal salt functions to aggregate fine fibrous cellulose, it can also be called a flocculant.

  Examples of metal salts containing divalent or higher metal components include aluminum sulfate (sulfate band), aluminum chloride, polyaluminum chloride, calcium chloride, magnesium chloride, calcium sulfate, magnesium sulfate, copper chloride, copper sulfate, iron chloride, Examples thereof include iron sulfate, lead chloride, lead sulfide and the like. As a metal salt containing a bivalent or higher-valent metal component, only one of the above-mentioned salts may be added, or two or more may be added. Among these, as the metal salt containing a divalent or higher-valent metal component, it is preferable to use at least one selected from aluminum sulfate (sulfate band), aluminum chloride, polyaluminum chloride, calcium chloride, and calcium sulfate. More preferably, at least one selected from calcium chloride is used.

  The content of the bivalent or higher metal component is preferably 0.5% by mass or less, more preferably 0.3% by mass or less, based on the total mass of the fibrous cellulose-containing material, It is more preferably no greater than mass%, even more preferably no greater than 0.15 mass%, and particularly preferably no greater than 0.1 mass%. The content of the metal component may be 0% by mass.

  In addition, content of the metal component more than bivalence in the fibrous cellulose containing material of this invention can be quantified by ICP-AES measurement (ICP emission spectroscopic analysis). When performing quantitative determination by ICP-AES measurement, first, 10 g of the fine fibrous cellulose-containing material is heated at 525 ° C. to be incinerated. Then, the ashed fine fibrous cellulose-containing material is dissolved in 5 mL of 1% nitric acid and wet-decomposed. The volume of this solution is adjusted to 50 mL, and a solution filtered through a 0.45 μm filter is used for ICP-AES measurement.

  In the present invention, when a bivalent or higher metal component is contained, the bivalent or higher metal component added in the production process of the fibrous cellulose-containing material is not completely removed and remains in the fibrous cellulose-containing material. Means that In the production process of fibrous cellulose-containing material, a metal component having a valence of 2 or more is added to a dispersion containing fibrous cellulose having a fiber width of 1000 nm or less, and then the metal component having a valence of 2 or more is removed by adding an acid. Is done. In this case, however, the divalent or higher-valent metal component is not completely removed by the acid, and a trace amount of the metal component is also contained in the fibrous cellulose-containing product as the final product.

(Surfactant)
The fibrous cellulose-containing material of the present invention may contain a surfactant. In the manufacturing process of the fibrous cellulose-containing material of the present invention, a pH adjusting agent such as an alkali component may be added to adjust the pH of the slurry of the fibrous cellulose-containing material. It is considered that the surfactant functions to facilitate the permeation between the fibers of the fibrous cellulose by lowering the surface tension of such a pH adjusting agent. Specifically, it serves to facilitate the permeation of the alkali solution added in the pH adjusting step described later between the fibers of the fibrous cellulose. For this reason, such surfactants can also be called penetration aids.

  The surfactant may be an ionic surfactant or a nonionic surfactant. Examples of the ionic surfactant include an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant. The nonionic surfactant is sometimes referred to as a nonionic surfactant. Among these, in the present invention, it is preferable to use a nonionic surfactant. When the fibrous cellulose-containing material contains a nonionic surfactant, the fine fibrous cellulose-containing material tends to exhibit excellent viscosity after redispersion even after long-term storage.

  Nonionic surfactants include, for example, polyoxyalkylene alkyl ether, polyglycerol fatty acid ester, glycerol mono fatty acid ester, glycerol di fatty acid ester, pluronic, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sucrose fatty acid ester, poly Examples thereof include oxyethylene acyl ester, alkyl polyglycoside, fatty acid methyl glycoside ester, alkyl methyl glucamide, and fatty acid alkanolamide. Among these, it is preferable to use polyoxyalkylene alkyl ether.

  Examples of the anionic surfactant include sodium oleate, potassium oleate, sodium laurate, sodium todecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene Examples include sodium ethylene alkylallyl ether sulfate, sodium polyoxyethylene dialkyl sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl allyl ether phosphate, and the like.

  Examples of the cationic surfactant include alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, acylaminoethyldiethylammonium salt, acylaminoethyldiethylamine salt, alkylamidopropyldimethylbenzylammonium salt, and alkylpyridinium salt. Quaternary ammonium salts such as alkylpyridinium sulfate, stearamide methylpyridinium salt, alkylquinolinium salt, alkylisoquinolinium salt, fatty acid polyethylene polyamide, acylaminoethylpyridinium salt, acylcoraminoformylmethylpyridinium salt, Stearooxymethylpyridinium salt, fatty acid triethanolamine, fatty acid triethanolamine formate, trioxyethylene Ester-linked amines such as fatty acid triethanolamine, cetyloxymethylpyridinium salt, p-isooctylphenoxyethoxyethyldimethylbenzylammonium salt, ether-bonded quaternary ammonium salts, alkylimidazolines, 1-hydroxyethyl-2-alkylimidazolines, Complexed amines such as 1-acetylaminoethyl-2-alkylimidazoline, 2-alkyl-4-methyl-4-hydroxymethyloxazoline, polyoxyethylene alkylamine, N-alkylpropylenediamine, N-alkylpolyethylenepolyamine, N- Examples thereof include amine derivatives such as alkyl polyethylene polyamine dimethyl sulfate, alkyl biguanide, and long chain amine oxide.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, cocamidopropyl betaine, lauramidopropyl betaine, and sodium cocoamphoacetate.

  The content of the surfactant is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more with respect to the total mass of the fibrous cellulose-containing material. Further, the content of the surfactant is preferably 5% by mass or less, more preferably 3% by mass or less, and more preferably 2% by mass or less with respect to the total mass of the fibrous cellulose-containing material. Further preferred. By setting the content of the surfactant within the above range, the fine fibrous cellulose-containing material tends to exhibit excellent thickening after redispersion even after long-term storage.

(Water-soluble organic compounds)
The fibrous cellulose-containing material of the present invention may contain a water-soluble organic compound. In the present invention, the water-soluble organic compound penetrates between adjacent fine fibrous celluloses, thereby acting as a spacer for providing a fine space between the fine fibrous celluloses. For this reason, a water-soluble organic compound can also be called a spacer molecule. In the fibrous cellulose-containing material having such spacer molecules, the fibrous cellulose aggregates to a state where it cannot be redispersed even when moisture existing between the fibrous celluloses is removed (moisture release). It is suppressed. For this reason, the redispersibility of the fibrous cellulose-containing material is further improved, and it becomes easy to form a highly transparent sheet from the redispersed liquid even after long-term storage. The water-soluble organic compound may be added in combination with the above-described surfactant, or may be added alone.

  The water-soluble organic compound is preferably non-volatile. By using a non-volatile water-soluble organic compound, it is suppressed from being lost after entering between the fine fibrous celluloses, and the redispersibility after long-term storage can be further improved. In addition, the viscosity and viscosity retention rate of the redispersed liquid can be increased. Here, the nonvolatile water-soluble organic compound in the present specification is, for example, a water-soluble organic compound having a boiling point of 100 ° C. or higher.

  The water-soluble organic compound preferably has at least one group contributing to hydrogen bonding in one molecule, more preferably two or more, and further preferably three or more. preferable. Examples of groups that contribute to hydrogen bonding include groups such as —OH, —NH, —O—, ═O, and ═N—.

  In one molecule of the water-soluble organic compound, the value obtained by dividing the number of groups contributing to hydrogen bonding by the number of carbon atoms constituting one molecule of the water-soluble organic compound is preferably 0.5 or more. It is more preferably 6 or more, and further preferably 0.7 or more. By using such a water-soluble organic compound, the redispersibility of the fibrous cellulose-containing material can be further improved. Moreover, the tendency for the viscosity retention of the fibrous cellulose-containing material to be improved is also observed.

  The total atomic weight of nitrogen atom (N), oxygen atom (O), sulfur atom (S) and phosphorus atom (P) with respect to the entire molecular weight of the water-soluble organic compound is preferably 25% or more, and 30% or more. More preferably, it is more preferably 40% or more, and particularly preferably 50% or more. By making the total ratio of the atomic weights of nitrogen, oxygen, sulfur and phosphorus within the above range, a fibrous cellulose-containing material excellent in redispersibility can be easily obtained. The total ratio of the atomic weights of nitrogen, oxygen, sulfur and phosphorus can be calculated from the constituent element ratio of the water-soluble organic compound or can be calculated by elemental analysis.

  Examples of water-soluble organic compounds include sugars, water-soluble polymers, urea, and the like. Specific examples include trehalose, urea, polyethylene glycol (PEG), polyethylene oxide (PEO), carboxymethyl cellulose, and polyvinyl alcohol (PVA). Further, as water-soluble organic compounds, alkyl methacrylate / acrylic acid copolymer, polyvinylpyrrolidone, sodium polyacrylate, propylene glycol, dipropylene glycol, polypropylene glycol, isoprene glycol, hexylene glycol, 1,3-butylene glycol, polyacrylamide , Xanthan gum, guar gum, tamarind gum, carrageenan, locust bean gum, quince seed, alginic acid, pullulan, carrageenan, pectin, thiolated starch, raw starch, oxidized starch, etherified starch, esterified starch, amylose and other starches, glycerin Diglycerin, polyglycerin, hyaluronic acid, and metal salts of hyaluronic acid can also be used. Among these, the water-soluble organic compound is preferably at least one selected from trehalose, polyethylene glycol (PEG), and urea.

  When a water-soluble polymer is used as the water-soluble organic compound, the molecular weight of the water-soluble polymer is preferably 100 or more, and more preferably 150 or more. Further, the molecular weight of the water-soluble polymer is preferably 50000 or less, and more preferably 30000 or less.

  The content of the water-soluble organic compound is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.5% by mass with respect to the total mass of the fibrous cellulose-containing material. More preferably, it is the above. Moreover, it is preferable that it is 30 mass% or less with respect to the total mass of a fibrous cellulose containing material, and, as for content of a water-soluble organic compound, it is more preferable that it is 20 mass% or less. By setting the content of the water-soluble organic compound within the above range, the fine fibrous cellulose-containing material can easily form a highly transparent sheet from the redispersed liquid even after long-term storage.

(Optional component)
The fibrous cellulose-containing material of the present invention may contain an optional component other than the components described above. Examples of optional components include antifoaming agents, lubricants, ultraviolet absorbers, dyes, pigments, stabilizers, alcohols, preservatives, organic fine particles, inorganic fine particles, resins, and the like. Moreover, you may add an organic ion as an arbitrary component.

  Moreover, a hygroscopic agent can also be mentioned as an arbitrary component. Examples of the hygroscopic agent include silica gel, zeolite, alumina, sepiolite, calcium oxide, diatomaceous earth, activated carbon, activated clay, white carbon, calcium chloride, magnesium chloride, potassium acetate, dibasic sodium phosphate, sodium citrate and the like. It is done.

(Method for producing fibrous cellulose-containing material)
The present invention also relates to a method for producing a fibrous cellulose-containing material, comprising a step of obtaining a dispersion containing fibrous cellulose having a fiber width of 1000 nm or less and a step of aggregating the fibrous cellulose. Examples of the step of aggregating fibrous cellulose include a step of adding a bivalent or higher metal component to the dispersion. Moreover, when including the process of adding such a bivalent or more metal component, it is preferable to further include the acid addition process for removing a metal component.

  The method for producing a fibrous cellulose-containing material may further include a pH adjustment step. The pH adjustment step is preferably a step of adjusting the pH so that the slurry has a pH of 4 or more when the fibrous cellulose-containing material is made into a slurry having a solid content concentration of 0.5% by mass.

  The step of obtaining a dispersion containing fibrous cellulose having a fiber width of 1000 nm or less is the step described in detail in the above item (Fibrous cellulose). The step of obtaining a dispersion containing fibrous cellulose having a fiber width of 1000 nm or less includes a substituent introduction step, an alkali treatment step, and a defibration treatment step.

  In the step of adding a divalent or higher metal component to the dispersion, it is preferable to add a metal salt containing a divalent or higher metal component. Examples of the metal salt containing a divalent or higher-valent metal component include the metal salts described above. In the step of adding a divalent or higher metal component to the dispersion, the metal salt containing the divalent or higher metal component is 1 part by mass or more with respect to 100 parts by mass of the fine fibrous cellulose contained in the dispersion. It is preferable to add to more preferably 5 parts by mass or more. Moreover, it is preferable to add a metal salt containing a bivalent or higher-valent metal component to 100 parts by mass or less with respect to 100 parts by mass of fine fibrous cellulose contained in the dispersion, and 50 parts by mass or less. It is more preferable to add so that.

  The step of adding the metal component preferably further includes a filtration step after adding the bivalent or higher metal component. Such a filtration step is provided between the metal component addition step and the acid addition step, and the concentrate can be efficiently obtained by providing the filtration step.

The filter medium used in the filtration step is not particularly limited, and filter media such as stainless steel, filter paper, polypropylene, nylon, polyethylene, and polyester can be used. Since an acid may be used, a polypropylene filter medium is preferable. The lower the air permeability of the filter medium, the higher the yield. Therefore, it is 30 cm ³ / cm ² · sec or less, more preferably 10 cm ³ / cm ² · sec or less, and further preferably 1 cm ³ / cm ² · sec or less.

  The filtration step may further include a compression step. In the compression step, a squeezing device can also be used. As such an apparatus, a general press apparatus such as a belt press, a screw press, or a filter press can be used, and the apparatus is not particularly limited. The pressure during compression is preferably 0.2 MPa or more, and more preferably 0.4 MPa or more.

  Next, the method for producing a fibrous cellulose-containing material preferably includes an acid addition step. In the method for producing a fibrous cellulose-containing material, at least one of the bivalent or higher metal components is added by adding a bivalent or higher metal component to a dispersion containing fibrous cellulose having a fiber width of 1000 nm or less, and then adding an acid. Part is removed. For this reason, an acid addition process is also called a metal salt removal process. In the acid addition step, it is preferable to remove as many metal components as possible, but it is impossible to completely remove the metal components, and 0.5 mass% or less in the fibrous cellulose-containing material as the final product. Some metal components may remain.

  The acid component added in the acid addition step may be either an inorganic acid or an organic acid. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and the like. Examples of the organic acid include formic acid, acetic acid, citric acid, malic acid, lactic acid, adipic acid, sebacic acid, stearic acid, maleic acid, succinic acid, tartaric acid, fumaric acid, and gluconic acid. Among these, it is preferable to add at least one selected from sulfuric acid and hydrochloric acid. The concentration of the acid component (acid solution) to be used is not particularly limited, but is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less. By setting the concentration of the acidic liquid in the above range, deterioration due to decomposition of cellulose can be suppressed. In addition, although at least one part may remain in a fibrous cellulose containing material among the said acids, it is preferable to neutralize an acid component by providing a pH adjustment process after an acid addition process.

  The acid addition step may further include a filtration step after adding the acid. Moreover, the filtration process may further include a compression process.

  The pH adjustment step is a step of adjusting the pH so that the slurry has a pH of 4 or more when the fibrous cellulose-containing material is made into a slurry having a solid content concentration of 0.5 mass%. Since the pH adjustment step is a step of neutralizing the acid component added in the acid addition step, it may be called a neutralization step. That is, an alkali component is added in the pH adjustment step. In addition, although at least one part may remain in a fibrous cellulose containing material among these alkali components, most is used for the neutralization reaction in a pH adjustment process.

  The alkali component added in the pH adjustment step may be an inorganic alkali compound or an organic alkali compound. Examples of the inorganic alkali compound include lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, and the like. Organic alkali compounds include ammonia, hydrazine, methylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, butylamine, diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, cyclohexylamine, aniline, tetramethyl Ammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, pyridine, N, N-dimethyl-4-aminopyridine and the like can be mentioned. Among them, at least one selected from lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, lithium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, sodium carbonate and sodium hydrogen carbonate is preferably used. Particularly preferably used.

  In the pH adjustment step, in addition to the alkali component, at least one selected from a surfactant and a water-soluble organic compound may be added. In this case, the surfactant and the water-soluble organic compound described above can be listed as the surfactant and the water-soluble organic compound to be added.

  In addition, at least 1 sort (s) selected from surfactant and a water-soluble organic compound may be added even when not providing a pH adjustment process. In this case, it is preferable that at least one selected from the surfactant and the water-soluble organic compound is provided in the subsequent step of the above-described metal component addition step or the acid addition step, and is provided in the subsequent step of the acid addition step. Is more preferable.

  When adding a surfactant in the production process of the fibrous cellulose-containing material, the surfactant is preferably added so as to be 0.001 part by mass or more with respect to 100 parts by mass of the fine fibrous cellulose, It is more preferable to add so that it may become 0.01 mass part or more, and it is still more preferable to add so that it may become 0.1 mass part or more. Moreover, it is preferable to add surfactant so that it may become 20 mass parts or less with respect to 100 mass parts of fine fibrous cellulose, and it is more preferable to add so that it may become 10 mass parts or less.

  When a water-soluble organic compound is added in the production process of the fibrous cellulose-containing material, it is preferably added so as to be 5 parts by mass or more with respect to 100 parts by mass of the fine fibrous cellulose. It is more preferable to add so that. Moreover, it is preferable to add a water-soluble organic compound so that it may become 200 mass parts or less with respect to 100 mass parts of fine fibrous cellulose, and it is more preferable to add so that it may become 100 mass parts or less.

  In addition to the process mentioned above, the manufacturing method of the fibrous cellulose containing material of this invention may further include the powdering process. When the method for producing a fibrous cellulose-containing material of the present invention includes a powdering step, methods such as mixer pulverization, spray drying, oven drying, and dehydration with an organic solvent can be employed. These methods can also be combined appropriately. The obtained fibrous cellulose-containing material may be a powder or a floc, flake, or paste.

(Redistribution)
The fine fibrous cellulose-containing material produced in the above-described process is preferably used by being redispersed in a solvent such as water. Although the kind of solvent used in order to obtain such a redispersion slurry is not specifically limited, Water, an organic solvent, and the mixture of water and an organic solvent can be mentioned. Examples of the organic solvent include alcohols, polyhydric alcohols, ketones, ethers, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, and t-butyl alcohol. Examples of polyhydric alcohols include ethylene glycol and glycerin. Examples of ketones include acetone and methyl ethyl ketone. Examples of ethers include diethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, and ethylene glycol mono t-butyl ether.

  The re-dispersion of the fine fibrous cellulose-containing material can be performed by a conventional method. For example, a step of preparing a liquid containing the fine fibrous cellulose-containing material by adding the above-described solvent to the fine fibrous cellulose-containing material, and dispersing the fine fibrous cellulose in the liquid containing the fine fibrous cellulose-containing material Redispersion can be performed by the process of making it.

  As the dispersing device used in the step of dispersing the fine fibrous cellulose in the liquid containing the fine fibrous cellulose-containing material, the same device as the defibrating treatment device described in the above <defibrating treatment> may be used. .

(Use)
The use of the fine fibrous cellulose-containing material of the present invention is not particularly limited. The fine fibrous cellulose-containing material is preferably used as a thickener, for example. In this case, the re-dispersed slurry of the fine fibrous cellulose-containing material should be used as a thickener for various purposes (for example, additives to foods, cosmetics, cement, paints, inks, underground layer processing fluids, etc.). Can do.

  The fine fibrous cellulose-containing material of the present invention can be mixed with a resin or emulsion and used for use as a reinforcing material. Moreover, it may shape | mold using the slurry of a fibrous cellulose containing material, and may produce a molded object. In this case, it is preferable to mix a resin or an emulsion with the slurry of the fibrous cellulose-containing material. The molded body may have various shapes other than the sheet shape. Furthermore, it can also form into a film using a fine fibrous cellulose redispersion slurry, and can also be used as various sheets.

(Sheet)
The fibrous cellulose-containing material of the present invention can be a highly transparent sheet. Specifically, when a sheet is formed from the fibrous cellulose-containing material of the present invention, the haze of the sheet is preferably 5% or less, more preferably 2% or less, and 1.5% or less. More preferably, it is 1% or less. Here, the haze of the sheet is a value measured using a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd., HM-150) in accordance with JIS K 7136.

  In the present invention, a highly transparent sheet can be formed even after long-term storage of the fibrous cellulose-containing material. Specifically, even after the fibrous cellulose-containing material is stored at 23 ° C. for 240 hours, a sheet satisfying the haze value can be formed.

  The thickness of the sheet used for haze measurement is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. Moreover, the upper limit of the thickness of the sheet is not particularly limited, but can be, for example, 1000 μm or less. In addition, the thickness of a sheet | seat can be measured with a stylus type thickness meter (Maltron 1202D by Marl).

Further, the basis weight of the sheet used for haze measurement is preferably 10 g / m ² or more, more preferably 20 g / m ² or more, and further preferably 30 g / m ² or more. Further, the basis weight of the sheet is preferably 100 g / m ² or less, and more preferably 80 g / m ² or less. Here, the basis weight of the sheet can be calculated in accordance with JIS P 8124.

(Sheet manufacturing method)
The manufacturing process of a sheet | seat includes the process of applying the re-dispersion liquid of the fine fibrous cellulose content obtained at the process mentioned above on a base material, or the process of making a paper of a re-dispersion liquid. In the present invention, the fine fibrous cellulose-containing material may be one after long-term storage, and even in such a case, a sheet having a low haze can be formed.

  It is preferable to provide a step of further adding a hydrophilic polymer to the redispersion liquid before the step of forming the redispersion liquid into a sheet. Examples of hydrophilic polymers include polyethylene glycol, cellulose derivatives (hydroxyethylcellulose, carboxyethylcellulose, carboxymethylcellulose, etc.), casein, dextrin, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol (acetoacetylated polyvinyl alcohol, etc.), Examples thereof include polyethylene oxide, polyvinyl pyrrolidone, polyvinyl methyl ether, polyacrylates, polyacrylamide, alkyl acrylate copolymer, urethane copolymer, and the like.

The content of the hydrophilic polymer is preferably 0.5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the fibrous cellulose. The viscosity average molecular weight of the hydrophilic polymer is not particularly limited, but is preferably 1.0 × 10 ³ or more and 1.0 × 10 ⁷ or less, and is 2.0 × 10 ³ or more and 1.0 × 10 ⁷ or less. More preferably, it is 5.0 × 10 ³ or more and 1.0 × 10 ⁷ or less.

<Coating process>
A coating process is a process of obtaining a sheet | seat by apply | coating a re-dispersion liquid on a base material, drying this, and peeling the sheet | seat formed from the base material. By using a coating apparatus and a long base material, sheets can be continuously produced.

  The quality of the base material used in the coating process is not particularly limited, but a sheet having higher wettability with respect to the redispersion liquid may be able to suppress shrinkage of the sheet during drying, but the sheet formed after drying. It is preferable to select one that can be easily peeled off. Among them, a resin plate or a metal plate is preferable, but not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, metal plates such as aluminum plates, zinc plates, copper plates, iron plates, etc., and those whose surfaces are oxidized, stainless steel A plate, a brass plate or the like can be used.

  In the coating process, when the redispersion liquid has a low viscosity and expands on the base material, a damming frame is fixed on the base material to obtain a sheet with a predetermined thickness and basis weight. May be. The quality of the damming frame is not particularly limited, but it is preferable to select one that can easily peel off the edge of the sheet attached after drying. Among them, a molded resin plate or metal plate is preferable, but is not particularly limited. For example, resin plates such as acrylic plates, polyethylene terephthalate plates, vinyl chloride plates, polystyrene plates, polyvinylidene chloride plates, metal plates such as aluminum plates, zinc plates, copper plates, iron plates, etc., and their surfaces oxidized, stainless steel A plate, a brass plate or the like can be used.

  As a coating machine for applying the redispersion liquid, for example, a roll coater, a gravure coater, a die coater, a curtain coater, an air doctor coater or the like can be used. A die coater, a curtain coater, and a spray coater are preferable because the thickness can be made more uniform.

  The coating temperature is not particularly limited, but is preferably 20 ° C or higher and 45 ° C or lower, more preferably 25 ° C or higher and 40 ° C or lower, and further preferably 27 ° C or higher and 35 ° C or lower. If the coating temperature is equal to or higher than the above lower limit value, the redispersion liquid can be easily applied. If the coating temperature is equal to or lower than the upper limit value, volatilization of the dispersion medium during coating can be suppressed.

  It is preferable that a coating process includes the process of drying the redispersion liquid coated on the base material. Although it does not specifically limit as a drying method, Either a non-contact drying method or the method of drying while restraining a sheet | seat may be sufficient, and these may be combined.

  The non-contact drying method is not particularly limited, but a method of drying by heating with hot air, infrared rays, far infrared rays or near infrared rays (heating drying method) or a method of drying in vacuum (vacuum drying method) is applied. Can do. Although the heat drying method and the vacuum drying method may be combined, the heat drying method is usually applied. Although drying by infrared rays, far infrared rays, or near infrared rays can be performed using an infrared device, a far infrared device, or a near infrared device, it is not particularly limited. The heating temperature in the heat drying method is not particularly limited, but is preferably 20 ° C. or higher and 150 ° C. or lower, and more preferably 25 ° C. or higher and 105 ° C. or lower. If the heating temperature is not less than the above lower limit value, the dispersion medium can be volatilized quickly, and if it is not more than the above upper limit value, it is possible to suppress the cost required for heating and to prevent the fine fibrous cellulose from being discolored by heat. .

<Paper making process>
The manufacturing process of the sheet may include a step of making the re-dispersed liquid. Examples of the paper machine in the paper making process include a continuous paper machine such as a long-mesh type, a circular net type, and an inclined type, and a multi-layered paper machine combining these. In the paper making process, known paper making such as hand making may be performed.

  In the paper making process, the redispersed liquid is filtered and dehydrated on a wire to obtain a wet paper sheet, and then the sheet is obtained by pressing and drying. When the re-dispersed liquid is filtered and dehydrated, the filter cloth at the time of filtration is not particularly limited, but it is important that fine fibrous cellulose and preservatives do not pass through and the filtration rate is not too slow. Although it does not specifically limit as such a filter cloth, The sheet | seat, fabric, and porous film which consist of organic polymers are preferable. The organic polymer is not particularly limited, but non-cellulosic organic polymers such as polyethylene terephthalate, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) and the like are preferable. Specific examples include a porous film of polytetrafluoroethylene having a pore size of 0.1 μm to 20 μm, for example, 1 μm, polyethylene terephthalate or polyethylene woven fabric having a pore size of 0.1 μm to 20 μm, for example, 1 μm, but is not particularly limited.

  The method for producing the sheet from the redispersion liquid is not particularly limited, and examples thereof include a method using a production apparatus described in WO2011 / 013567. This manufacturing apparatus discharges a redispersion liquid containing fine fibrous cellulose onto the upper surface of an endless belt, and squeezes a dispersion medium from the discharged redispersion liquid to generate a web, and dries the web. And a drying section for producing a fiber sheet. An endless belt is disposed from the squeezing section to the drying section, and the web generated in the squeezing section is conveyed to the drying section while being placed on the endless belt.

  The dehydration method that can be employed is not particularly limited, and examples thereof include a dehydration method that is usually used in paper production. A method of dehydrating with a long net, a circular net, an inclined wire, etc., and then dehydrating with a roll press is preferable. The drying method is not particularly limited, and examples thereof include methods used in paper production. For example, methods such as a cylinder dryer, a Yankee dryer, hot air drying, a near infrared heater, and an infrared heater are preferable.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

<Production Example 1>
Oji Paper's pulp (solid content 93% by weight, basis weight 208 g / m ² sheet, Canadian standard freeness (CSF) 700 ml measured by disaggregation and measured according to JIS P 8121) is used as the conifer kraft pulp did. 100 parts by mass (absolute dry mass) of the above-mentioned softwood kraft pulp is impregnated with a mixed aqueous solution of ammonium dihydrogen phosphate and urea, and compressed to 49 parts by mass of ammonium dihydrogen phosphate and 130 parts by mass of urea. Pulp was obtained. The obtained chemical solution-impregnated pulp was dried with a dryer at 105 ° C. to evaporate the moisture and pre-dried. Then, it heated for 10 minutes with the ventilation dryer set to 140 degreeC, the phosphate group was introduce | transduced into the cellulose in a pulp, and the phosphorylated pulp was obtained.

  100 g of the obtained phosphorylated pulp was collected at an absolutely dry mass, 10 L of ion exchange water was poured, and the mixture was stirred and dispersed uniformly, followed by filtration and dehydration to obtain a dehydrated sheet twice. Next, the obtained dehydrated sheet was diluted with 10 L of ion exchange water, and a 1N sodium hydroxide aqueous solution was added little by little while stirring to obtain a pulp slurry having a pH of 12 to 13. Thereafter, the pulp slurry was dehydrated to obtain a dehydrated sheet, and then 10 L of ion exchange water was added. The step of stirring and dispersing uniformly, followed by filtration and dehydration to obtain a dehydrated sheet was repeated twice.

In the same manner as described above, the step of introducing phosphate groups and the step of filtration and dehydration were repeated on the obtained dehydrated sheet to obtain a dehydrated sheet of phosphorylated cellulose. The infrared absorption spectrum of the obtained dehydration sheet was measured by FT-IR. As a result, absorption based on phosphate groups was observed at 1230 cm ⁻¹ or more and 1290 cm ⁻¹ or less, and addition of phosphate groups was confirmed.

  Ion exchange water was added to the obtained phosphorylated cellulose to prepare a 2% by mass slurry. This slurry was further treated three times at a pressure of 245 MPa with a wet atomization apparatus (manufactured by Sugino Machine, Optimizer) to obtain fine fibrous cellulose A. It was confirmed by X-ray diffraction that this fine fibrous cellulose maintained cellulose I type crystals.

<Production Example 2>
In Production Example 1, fine fibrous cellulose B was obtained by passing a single disc refiner having a clearance of 100 μm three times instead of the optimizer treatment. It was confirmed by X-ray diffraction that this fine fibrous cellulose maintained cellulose I type crystals.

<Measurement of substituent amount>
The amount of substituent introduction is the amount of phosphate groups introduced into the fiber material, and the larger this value, the more phosphate groups are introduced. The amount of substituent introduced was measured by diluting the target fine fibrous cellulose with ion-exchanged water so that the content was 0.2% by mass, and then treating with ion-exchange resin and titration with alkali. In the treatment with an ion exchange resin, 1/10 by volume of a strongly acidic ion exchange resin (Amberjet 1024; Organo Co., Ltd., conditioned) is added to the 0.2 mass% fibrous cellulose-containing slurry and shaken for 1 hour. Went. Thereafter, the mixture was poured onto a mesh having an opening of 90 μm to separate the resin and the slurry. In titration using an alkali, a change in the value of electrical conductivity exhibited by the slurry was measured while adding a 0.1N sodium hydroxide aqueous solution to the fibrous cellulose-containing slurry after ion exchange. That is, the alkali amount (mmol) required in the first region of the curve shown in FIG. 1 (phosphate group) is divided by the solid content (g) in the titration target slurry, and the substituent introduction amount (mmol / g). As a result of the calculation, both the fine fibrous celluloses A and B were 1.60 mmol / g.

<Measurement of fiber width>
The fiber width of the fine fibrous cellulose was measured by the following method.
The supernatant liquid of the defibrated pulp slurry was diluted with water to a concentration of 0.01% by mass or more and 0.1% by mass or less and dropped onto a carbon grid membrane subjected to a hydrophilic treatment. After drying, it was stained with uranyl acetate and observed with a transmission electron microscope (JEOL-2000EX, manufactured by JEOL Ltd.). It was confirmed that the fine fibrous cellulose A was a fine fibrous cellulose having a width of about 4 nm. Moreover, it confirmed that the coarse fibrous fiber measured by the method mentioned later and the fine fiber of width 1000nm or less were mixed in the fine fibrous cellulose B.

<Measurement of coarse cellulose fiber content>
The amount of coarse cellulose fibers was measured by the following method. First, ion-exchange water was added to the slurry of fine fibrous cellulose to adjust the fiber solid content concentration to 0.2% by mass. Next, the mixture was centrifuged at 12000 G × 10 min using a cooling high-speed centrifuge (Kokusan Co., Ltd., H-2000B), and the resulting supernatant was collected. And the solid content density | concentration of the supernatant liquid was measured. And the ratio of the coarse cellulose fiber was computed by the following formula.
Ratio of coarse cellulose fiber (%) = 100− (solid content concentration of supernatant / 0.2% by mass × 100)
As a result of calculating the amount of coarse cellulose fibers for fine fibrous cellulose A and fine fibrous cellulose B, fine fibrous cellulose A was 0.9% and fine fibrous cellulose B was 86.4%.

<Example 1>
500 g of a dispersion (2% by mass) of fine fibrous cellulose A was taken, and 250 g of a calcium chloride aqueous solution diluted to 0.5% by mass was added thereto for gelation. After filtration, the mixture was pressed with filter paper to obtain a concentrate 1 having a fine fibrous cellulose concentration of 20% by mass. This concentrate was immersed in 250 g of 0.1N hydrochloric acid aqueous solution for 30 minutes, then filtered, and pressed with a filter paper to obtain a concentrate 2 having a fine fibrous cellulose concentration of 20% by mass. Add 100 parts by weight of 0.35N sodium hydroxide aqueous solution and 0.2 parts by weight of nonionic surfactant (San Nopco, SN wet PUR) to 100 parts by weight of concentrate 2, and mix well with a spoon. Then, the mixture was pulverized with a mixer (Milcer 800DG, manufactured by Iwatani Corporation) to obtain a fine fibrous cellulose-containing product (concentrate 3) having a fine fibrous cellulose concentration of 10% by mass.

<Example 2>
In Example 1, during the preparation of the sample, the concentrate was squeezed in the second pressing until the concentration of fine fibrous cellulose was not 20% by mass, but the concentration of fine fibrous cellulose was 40% by mass. Obtained. To 100 parts by mass of concentrate 2, 0.7N sodium hydroxide aqueous solution was added to 100 parts by mass and nonionic surfactant (SN wet PUR) was added to 0.4 parts by mass, and mixed to obtain fine fibrous cellulose. A fine fibrous cellulose-containing material (concentrate 3) was obtained in the same manner as in Example 1 except that a concentrate having a concentration of 20% by mass was obtained.

<Example 3>
In Example 1, during the preparation of the sample, the concentrate was squeezed in the second pressing until the concentration of fine fibrous cellulose was not 20% by mass, but the concentration of fine fibrous cellulose was 40% by mass. Obtained. For 100 parts by mass of concentrate 2, a 0.7N sodium hydroxide aqueous solution is 92 parts by mass, a nonionic surfactant (SN wet PUR) is 0.4 parts by mass, and trehalose (manufactured by Tokyo Chemical Industry Co., Ltd.) is 8 parts by mass. A fine fibrous cellulose-containing material (concentrate 3) was obtained in the same manner as in Example 1 except that a concentrate having a fine fibrous cellulose concentration of 20% by mass was obtained. .

<Example 4>
In Example 3, a fine fibrous cellulose-containing material (Concentrate 3) was obtained in the same manner as in Example 3 except that polyethylene glycol 200 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of trehalose.

<Example 5>
In Example 1, a fine fibrous cellulose-containing material (Concentrate 3) was obtained in the same manner as in Example 1 except that the nonionic surfactant (SN wet PUR) was not added.

<Example 6>
In Example 2, a fine fibrous cellulose-containing material (Concentrate 3) was obtained in the same manner as in Example 2 except that the nonionic surfactant (SN wet PUR) was not added.

<Example 7>
Trehalose is mixed at 0.5 parts by mass with respect to 100 parts by mass of the fine fibrous cellulose A dispersion (2% by mass), and dried with a dryer at 50 ° C., so that the concentration of the fine fibrous cellulose is 70 masses. % Concentrate was obtained.

<Comparative Example 1>
In Example 1, a fine fibrous cellulose-containing material (concentrate) was obtained in the same manner as in Example 1 except that the aqueous sodium hydroxide solution and the nonionic surfactant (SN wet PUR) were not added.

<Comparative example 2>
In Example 1, a fine fibrous cellulose-containing material (concentrate) was obtained in the same manner as in Example 1 except that fine fibrous cellulose B was used instead of fine fibrous cellulose A.

<Comparative Example 3>
In Example 7, a fine fibrous cellulose-containing material (concentrate) was obtained in the same manner as in Example 7 except that drying was performed without adding trehalose to obtain an 85 mass% concentrate. However, even if it was attempted to be dispersed in water after drying, fine fibrous cellulose was precipitated, and a uniform dispersion was not obtained, so evaluation was not performed.

(Evaluation)
(Evaluation of condition 1)
The fine fibrous cellulose-containing material (concentrate) obtained in Examples and Comparative Examples was added to ion-exchanged water, and 100 g of a slurry having a solid content concentration of 0.5% by mass was produced. Thereafter, 1N sodium hydroxide was added dropwise while stirring with a magnetic stirrer to adjust the pH of the slurry to 10. This slurry was stirred for 5 minutes at 1500 rpm (2250 r · cm / m) with a disperser (stirring TK Robotics, manufactured by Tokushu Kika Kogyo Co., Ltd., using a stirring blade with a radius of 1.5 cm). After 24 hours, the slurry was diluted to 0.4% by mass with ion exchange water, and stirred with a disperser at 2250 r · cm / m for 5 minutes. The obtained slurry was put into a 50 mL capacity glass screw bottle, and processed in a defoaming mode at 2200 rpm for 2 minutes with a rotation and revolution super mixer (ARE-250, manufactured by Shinkey Corp.). The mixture was allowed to stand in an environment of 23 ° C. for 24 hours, and rotated at 23 ° C. for 3 minutes at a rotation speed of 3 rpm using a B-type viscometer (manufactured by BLOOKFIELD, analog viscometer T-LVT) to measure the initial viscosity.

(Evaluation of condition 2)
After the fine fibrous cellulose-containing material (concentrate) obtained in Examples and Comparative Examples was stored at 23 ° C. for 10 days, it was dispersed and evaluated in the same manner as in the condition 1, and the viscosity ηB was measured. In addition, a slurry with a stirring force of 8000 rpm (12000 r · cm / m) for preparing a 0.5 mass% slurry was prepared, and the viscosity ηC was measured by performing dilution, defoaming and viscosity measurement in the same procedure. did.

(Evaluation of condition 3)
After the fine fibrous cellulose-containing material (concentrate) obtained in Examples and Comparative Examples was stored at 50 ° C. for 3 days, it was dispersed and evaluated in the same manner as in the evaluation of Condition 2, and the viscosity ηD (at 2250 r · cm / m Dispersion) and ηE (dispersion at 12000 r · cm / m) were measured.

(PH of slurry)
The fine fibrous cellulose-containing material (concentrate) obtained in Examples and Comparative Examples was added to ion-exchanged water, and 100 g of a slurry having a solid content concentration of 0.5% by mass was produced. The mixture was stirred with a magnetic stirrer, and the pH was measured after the whole was mixed (after 5 minutes or more).

(Create a sheet)
After the fine fibrous cellulose-containing material (concentrate) obtained in Examples and Comparative Examples was stored at 23 ° C. for 10 days, it was added to ion-exchanged water so as to be 0.5% by mass, and a 1N sodium hydroxide aqueous solution was added. The slurry was added dropwise, the pH was adjusted to 10, and a slurry was prepared. A 0.5% by mass aqueous solution of polyethylene glycol 4000000 (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 100 parts by mass of the slurry so that polyethylene glycol was 15 parts by mass. The mixed solution was weighed so that the finished basis weight was 30 g / m ² , developed on an acrylic plate, and dried in an oven at 50 ° C. In addition, the board for a dam was arrange | positioned on an acrylic board so that it might become predetermined | prescribed basic weight, and it was made for the sheet | seat obtained to become a rectangle. The haze of this sheet was measured using a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd., HM-150) according to JIS K 7136.

  As shown in Table 1, by producing a concentrate satisfying the conditions 1 and 2, it was possible to obtain a concentrate that was dispersed after storage and that had a low haze value when formed into a sheet. On the other hand, the concentrate of the comparative example was not satisfactory in haze value when formed into a sheet.

Claims (6)

A fibrous cellulose-containing material containing fibrous cellulose having a fiber width of 1000 nm or less,
Content of the said fibrous cellulose is 5 mass% or more with respect to the total mass of the said fibrous cellulose containing material,
When the viscosity measured under the following condition 1 is 3000 mPa · s or more, the viscosity measured under the following condition 2a is ηB, and the viscosity measured under the following condition 2b is ηC, the value of ηB / ηC is 0. A fibrous cellulose content greater than 7;
(Condition 1)
The fibrous cellulose-containing material is dispersed in water so that the solid content concentration is 0.45 mass% or more and 0.7 mass% or less, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry A; After allowing A to stand at 23 ° C. for 24 hours, it is diluted so that the solid content concentration is 0.4 mass%, and stirred for 5 minutes at a stirring speed of 2250 r · cm / min to obtain slurry B; Stir for 2 minutes at a stirring speed of 2200 rpm using a revolutionary stirrer and let stand at 23 ° C. for 24 hours, then rotate for 3 minutes at 23 ° C. and 3 rpm to measure the viscosity using a B-type viscometer;
(Condition 2a)
Viscosity is measured in the same manner as described above (Condition 1) except that the fibrous cellulose-containing material that is allowed to stand at 23 ° C. for 240 hours is used;
(Condition 2b)
The fibrous cellulose-containing material that was allowed to stand at 23 ° C. for 240 hours was dispersed in water so that the solid content concentration was 0.45 mass% or more and 0.7 mass% or less, and the mixture was stirred for 5 minutes at a stirring speed of 12000 r · cm / min. Thus, slurry A ′ is obtained; the viscosity is measured in the same manner as in (Condition 1) except that slurry A ′ is used instead of slurry A.   The fibrous cellulose-containing material according to claim 1, wherein the content of the metal component is 0.5% by mass or less based on the total mass of the fibrous cellulose-containing material.   The fibrous cellulose-containing material according to claim 1 or 2, which is solid. The value of (eta) D / (eta) E is larger than 0.7 when the viscosity measured on the following conditions 3a is set to (eta) D, and the viscosity measured on the following conditions 3b is set to (eta) E. Containing fibrous cellulose;
(Condition 3a)
Viscosity is measured in the same manner as described above (Condition 1) except that the fibrous cellulose-containing material that is allowed to stand at 50 ° C. for 72 hours is used;
(Condition 3b)
Viscosity is measured in the same manner as described above (Condition 2b) except that a fibrous cellulose-containing material that has been allowed to stand at 50 ° C. for 72 hours is used.   The fibrous cellulose-containing material according to any one of claims 1 to 4, further comprising a surfactant.   The fibrous cellulose-containing product according to any one of claims 1 to 5, further comprising a water-soluble organic compound.

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