WO2019176465A1 - Procédé de production d'une dispersion de nanofibres de cellulose - Google Patents

Procédé de production d'une dispersion de nanofibres de cellulose Download PDF

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Publication number
WO2019176465A1
WO2019176465A1 PCT/JP2019/006001 JP2019006001W WO2019176465A1 WO 2019176465 A1 WO2019176465 A1 WO 2019176465A1 JP 2019006001 W JP2019006001 W JP 2019006001W WO 2019176465 A1 WO2019176465 A1 WO 2019176465A1
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Prior art keywords
cellulose
plate
preliminary
defibration
nanofiber dispersion
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PCT/JP2019/006001
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English (en)
Japanese (ja)
Inventor
利一 村松
啓吾 渡部
淳之 重見
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日本製紙株式会社
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Priority to JP2020505716A priority Critical patent/JP7402154B2/ja
Publication of WO2019176465A1 publication Critical patent/WO2019176465A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B15/00—Preparation of other cellulose derivatives or modified cellulose, e.g. complexes
    • C08B15/02—Oxycellulose; Hydrocellulose; Cellulosehydrate, e.g. microcrystalline cellulose
    • C08B15/04—Carboxycellulose, e.g. prepared by oxidation with nitrogen dioxide
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
    • D21D1/20—Methods of refining
    • D21D1/30—Disc mills
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
    • D21H11/18—Highly hydrated, swollen or fibrillatable fibres
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H15/00—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
    • D21H15/02—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution characterised by configuration

Definitions

  • the present invention relates to a method for producing a highly transparent cellulose nanofiber dispersion that is produced with low power consumption.
  • Cellulose nanofibers obtained by refining cellulose are fibers having a nano-level fiber diameter of about 1 to 100 nm, and the dispersion has high transparency. For this reason, application to transparency, for example, optical film, film coating agent, compounding to glass, etc. is expected. For this reason, various studies have been made on methods for producing cellulose nanofibers (see Patent Document 1).
  • An object of the present invention is to provide a method for producing a cellulose nanofiber dispersion that efficiently produces a highly transparent cellulose nanofiber dispersion with low power consumption.
  • the present invention provides the following (1) to (7).
  • a method for producing a cellulose nanofiber dispersion comprising producing a highly transparent cellulose nanofiber dispersion from chemically modified cellulose, comprising the following steps (A) and (B): Step (A): preliminary defibrating step of beating the chemically modified cellulose using a single disc type refiner, Step (B): This defibrating step of defibrating the cellulose obtained in the preliminary defibrating step (A) by treatment with a high-pressure disperser at a treatment pressure of 1 MPa to 400 MPa.
  • the plate used in the refiner is a viscous beating plate, a fine bar type plate, a plate having a structure for closing the raw material flow path, a grindstone plate, a flat without a groove.
  • the method for producing a cellulose nanofiber dispersion according to (1) which is any one of metal plates.
  • the concentration of the chemically modified cellulose during treatment is 2.5 to 15% by mass, according to any one of (1) to (3) Of manufacturing cellulose nanofiber dispersion liquid.
  • the present invention it is possible to provide a method for efficiently producing a highly transparent cellulose nanofiber dispersion with low power consumption. Moreover, according to this invention, generation
  • the method for producing a cellulose nanofiber dispersion according to the present invention includes a step (A): a preliminary defibrating step of beating a chemically modified cellulose using a single disk type refiner, and a step (B): the preliminary defibrating step. And a main defibrating step of defibrating the cellulose obtained in (A) by treatment with a high-pressure disperser at a treatment pressure of 1 MPa to 400 MPa.
  • cellulose fibers are defibrated by different mechanisms by combining preliminary defibration by mechanical beating processing with a conventional beating device and main defibration, so that while reducing power consumption, transparency can be reduced.
  • a high cellulose nanofiber dispersion can be produced.
  • a highly transparent cellulose nanofiber dispersion can be obtained by the present invention.
  • the refinement of chemically modified cellulose as a raw material proceeds, and the outside of the cellulose fiber is loosened. Therefore, in this subsequent defibration, shear energy such as an ultra-high pressure homogenizer easily acts on the cellulose, and a cellulose nanofiber dispersion with high transparency can be produced efficiently.
  • the cellulose raw material refers to materials in various forms mainly composed of cellulose, and pulp (bleached or unbleached wood pulp, bleached or unbleached non-wood pulp, refined linter, jute, Manila hemp , Pulp derived from herbs such as kenaf), natural cellulose such as cellulose produced by microorganisms such as acetic acid bacteria, regenerated cellulose spun after dissolving cellulose in some solvent such as copper ammonia solution, morpholine derivative, and the above Examples thereof include fine cellulose obtained by depolymerizing cellulose by subjecting the cellulose raw material to mechanical treatment such as hydrolysis, alkaline hydrolysis, enzymatic decomposition, explosion treatment, and vibration ball mill.
  • mechanical treatment such as hydrolysis, alkaline hydrolysis, enzymatic decomposition, explosion treatment, and vibration ball mill.
  • the oxidation of the cellulose raw material can be performed using a known method, and is not particularly limited, but the amount of carboxyl groups is 0.5 mmol / g with respect to the absolute dry mass of the cellulose nanofiber. It is preferable to adjust so as to be ⁇ 3.0 mmol / g.
  • cellulose can be obtained by oxidizing cellulose in water in the presence of an N-oxyl compound and a compound selected from the group consisting of bromide, iodide, or a mixture thereof.
  • an N-oxyl compound and a compound selected from the group consisting of bromide, iodide, or a mixture thereof.
  • the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized, and a cellulose fiber having an aldehyde group and a carboxyl group or a carboxylate group on the surface can be obtained.
  • the concentration of cellulose during the reaction is not particularly limited, but is preferably 5% by mass or less.
  • An N-oxyl compound refers to a compound capable of generating a nitroxy radical. As the N-oxyl compound, any compound can be used as long as it promotes the target oxidation reaction.
  • the amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount capable of oxidizing the cellulose as a raw material.
  • a catalytic amount capable of oxidizing the cellulose as a raw material For example, with respect to 1 g of absolutely dry cellulose, 0.01 to 10 mmol is preferable, 0.02 to 1 mmol is more preferable, and 0.05 to 0.5 mmol is more preferable. Further, it is preferably about 0.1 to 4 mmol / L with respect to the reaction system.
  • Bromide is a compound containing bromine, and examples thereof include alkali metal bromide that can be dissociated and ionized in water.
  • an iodide is a compound containing iodine, and examples thereof include alkali metal iodide.
  • the amount of bromide or iodide used can be selected as long as the oxidation reaction can be promoted.
  • the total amount of bromide and iodide is, for example, preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, and further preferably 0.5 to 5 mmol with respect to 1 g of absolutely dry cellulose.
  • oxidizing agent known ones can be used, and for example, halogen, hypohalous acid, halous acid, perhalogen acid or salts thereof, halogen oxide, peroxide and the like can be used.
  • sodium hypochlorite is preferable because it is inexpensive and has a low environmental impact.
  • the appropriate amount of the oxidizing agent used is, for example, preferably 0.5 to 500 mmol, more preferably 0.7 to 50 mmol, still more preferably 1 to 25 mmol, and most preferably 3 to 10 mmol with respect to 1 g of absolutely dry cellulose. . Further, for example, 1 to 40 mol is preferable with respect to 1 mol of the N-oxyl compound.
  • the reaction temperature is preferably 4 to 40 ° C., and may be room temperature of about 15 to 30 ° C.
  • a carboxyl group is generated in the cellulose, so that the pH of the reaction solution is reduced.
  • an alkaline solution such as an aqueous sodium hydroxide solution is added to maintain the pH of the reaction solution at about 8 to 12, preferably about 10 to 11.
  • the reaction medium is preferably water because it is easy to handle and hardly causes side reactions.
  • the reaction time in the oxidation reaction can be appropriately set according to the progress of oxidation, and is usually 0.5 to 6 hours, for example, about 1 to 4 hours.
  • the oxidation reaction may be performed in two stages. For example, by oxidizing the oxidized cellulose obtained by filtration after the completion of the first-stage reaction again under the same or different reaction conditions, the efficiency is not affected by the reaction inhibition by the salt generated as a by-product in the first-stage reaction. Can be oxidized well.
  • Another example of the carboxylation (oxidation) method is a method of oxidizing by contacting a gas containing ozone and a cellulose raw material.
  • oxidation reaction By this oxidation reaction, at least the hydroxyl groups at the 2nd and 6th positions of the glucopyranose ring are oxidized and the cellulose chain is decomposed.
  • the ozone concentration in the gas containing ozone is preferably 50 to 250 g / m 3 , and more preferably 70 to 220 g / m 3 .
  • the amount of ozone added to the cellulose raw material is preferably 0.1 to 30 parts by mass, and more preferably 5 to 30 parts by mass, when the solid content of the cellulose raw material is 100 parts by mass.
  • the ozone treatment temperature is preferably 0 to 50 ° C., and more preferably 20 to 50 ° C.
  • the ozone treatment time is not particularly limited, but is about 1 to 360 minutes, preferably about 30 to 300 minutes. When the conditions for the ozone treatment are within these ranges, the cellulose can be prevented from being excessively oxidized and decomposed, and the yield of oxidized cellulose is improved.
  • an additional oxidation treatment may be performed using an oxidizing agent.
  • the oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite, oxygen, hydrogen peroxide, persulfuric acid, peracetic acid and the like. For example, these oxidizing agents can be dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and a cellulose raw material can be immersed in the solution for additional oxidation treatment.
  • the amount of the carboxyl group, carboxylate group, and aldehyde group of the cellulose fiber can be adjusted by controlling the amount of the oxidizing agent added and the reaction time.
  • the carboxyl group content is measured, for example, by preparing 60 mL of a 0.5 mass% slurry (aqueous dispersion) of oxidized cellulose, adding 0.1 M hydrochloric acid aqueous solution to pH 2.5, and then adding 0.05 N sodium hydroxide.
  • the electrical conductivity was measured by dropping the aqueous solution until the pH reached 11, and the amount was calculated from the amount of sodium hydroxide (a) consumed in the neutralization step of the weak acid where the change in electrical conductivity was slow, using the following formula: can do.
  • Amount of carboxyl group [mmol / g oxidized cellulose or cellulose nanofiber] A [mL] x 0.05 / oxidized cellulose mass [g]
  • the carboxymethylation of the cellulose raw material can be performed using a known method, and is not particularly limited.
  • the degree of carboxymethyl group substitution per anhydroglucose unit of cellulose is 0.01 to 0.00. It is preferable to adjust to 50.
  • the following production method can be mentioned, but it may be synthesized by a conventionally known method or a commercially available product may be used.
  • Cellulose is used as a starting material, and 3 to 20 times by weight water and / or lower alcohol as a solvent, specifically methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, tertiary butanol, etc.
  • the mixing ratio of the lower alcohol is 60 to 95% by mass.
  • the mercerizing agent 0.5 to 20 times moles of alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide is used per anhydroglucose residue of the bottoming material.
  • a bottoming raw material, a solvent, and a mercerizing agent are mixed, and a mercerization process is performed at a reaction temperature of 0 to 70 ° C., preferably 10 to 60 ° C., and a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours.
  • a carboxymethylating agent is added in an amount of 0.05 to 10.0 times mol per glucose residue, a reaction temperature of 30 to 90 ° C., preferably 40 to 80 ° C., and a reaction time of 30 minutes to 10 hours, preferably 1 hour.
  • the etherification reaction is performed for ⁇ 4 hours.
  • the following method can be used. That is, 1) About 2.0 g of carboxymethylated cellulose fiber (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) Add 100 mL of a solution of 100 mL of special concentrated nitric acid to 1000 mL of nitric acid methanol and shake for 3 hours to convert the carboxymethyl cellulose salt (CM cellulose) into hydrogenated CM cellulose. 3) Weigh accurately 1.5 to 2.0 g of hydrogenated CM-modified cellulose (absolutely dry), and put into a 300 mL Erlenmeyer flask with a stopper.
  • CM cellulose carboxymethyl cellulose salt
  • F ′ Factor of 0.1N H 2 SO 4
  • F Factor of 0.1N NaOH
  • the cationization of the cellulose raw material can be performed using a known method, and for example, ammonium, phosphonium, sulfonium, or a group having ammonium, phosphonium or sulfonium can be contained in the cellulose molecule by cationization.
  • a group containing ammonium is preferred, and a group containing quaternary ammonium is particularly preferred.
  • a specific cationization method is not particularly limited, but as an example, a cationizing agent such as glycidyltrimethylammonium chloride, 3-chloro-2hydroxypropyltrimethylammonium chloride or a halohydrin type thereof is used as a cellulose raw material.
  • Cationic modification having a group containing a quaternary ammonium by reacting a catalyst alkali metal hydroxide (sodium hydroxide, potassium hydroxide, etc.) in the presence of water and / or an alcohol having 1 to 4 carbon atoms.
  • a catalyst alkali metal hydroxide sodium hydroxide, potassium hydroxide, etc.
  • Cellulose can be obtained.
  • the degree of cation substitution per glucose unit of the cation-modified cellulose obtained is controlled by the addition amount of the cationizing agent to be reacted, the composition ratio of water and / or alcohol having 1 to 4 carbon atoms. Can be adjusted.
  • the degree of substitution herein refers to the number of substituents introduced per unit structure (glucopyranose ring) constituting cellulose. In other words, it is defined as “a value obtained by dividing the number of moles of the introduced substituent by the total number of moles of hydroxyl groups of the glucopyranose ring”. Since pure cellulose has three substitutable hydroxyl groups per unit structure (glucopyranose ring), the theoretical maximum value of the degree of substitution of the cellulose fiber of the present invention is 3 (minimum value is 0).
  • the degree of cation substitution per glucose unit of cationized cellulose is preferably 0.01 to 0.40.
  • the celluloses repel each other electrically. For this reason, the cellulose which introduce
  • the cation substitution degree per glucose unit is smaller than 0.01, nano-defibration cannot be sufficiently performed.
  • the degree of cation substitution per glucose unit is larger than 0.40, the fiber form cannot be maintained because it swells or dissolves and may not be obtained as a nanofiber.
  • the degree of cation substitution per glucose unit can be calculated from the following equation by measuring the nitrogen content with a total nitrogen analyzer TN-10 (Mitsubishi Chemical) after drying the sample (cation-modified cellulose). .
  • the degree of substitution referred to here represents the average value of the number of moles of substituents per mole of anhydroglucose unit.
  • Degree of cation substitution (162 ⁇ N) / (1-151.6 ⁇ N) N: Nitrogen content
  • a method for obtaining an esterified cellulose fiber or an esterified cellulose nanofiber by esterifying a cellulose raw material or a defibrated cellulose fiber is not particularly limited, and examples thereof include a method of reacting compound A with a cellulose raw material or a defibrated cellulose fiber. It is done. Compound A will be described later.
  • Examples of the method of reacting compound A with cellulose raw material or defibrated cellulose fiber include a method of mixing powder or aqueous solution of compound A with cellulose raw material or defibrated cellulose fiber, and compound A into a slurry of cellulose raw material or defibrated cellulose fiber.
  • the method of adding the aqueous solution of this is mentioned.
  • a method in which an aqueous solution of Compound A is mixed with a cellulose raw material, a defibrated cellulose fiber or a slurry thereof is preferable.
  • compound A examples include phosphoric acid compounds (eg, phosphoric acid, polyphosphoric acid), phosphorous acid, phosphonic acid, polyphosphonic acid, and esters thereof.
  • Compound A may be in the form of a salt.
  • a phosphoric acid compound is preferable because it is low in cost, easy to handle, and can improve the fibrillation efficiency by introducing a phosphate group into cellulose of a cellulose raw material (eg, pulp fiber).
  • the phosphate compound may be any compound having a phosphate group.
  • phosphoric acid sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, sodium pyrophosphate, sodium metaphosphate, diphosphate
  • examples include potassium hydrogen, dipotassium hydrogen phosphate, tripotassium phosphate, potassium pyrophosphate, potassium metaphosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, triammonium phosphate, ammonium pyrophosphate, and ammonium metaphosphate.
  • the phosphoric acid compound used may be one type or a combination of two or more types.
  • phosphoric acid phosphoric acid sodium salt, phosphoric acid potassium salt, phosphoric acid
  • Ammonium salt is preferable, sodium salt of phosphoric acid is more preferable, and sodium dihydrogen phosphate and disodium hydrogen phosphate are more preferable.
  • the pH of the aqueous solution of the phosphoric acid compound is preferably 7 or less because the efficiency of introduction of phosphate groups is increased. From the viewpoint of suppressing the hydrolysis of pulp fibers, a pH of 3 to 7 is more preferable.
  • esterification method examples include the following methods.
  • Compound A is added to a cellulose raw material or a suspension of defibrated cellulose fibers (for example, a solid content concentration of 0.1 to 10% by mass) with stirring to introduce phosphate groups into the cellulose.
  • the cellulose raw material or defibrated cellulose fiber is 100 parts by mass
  • the compound A is a phosphoric acid compound
  • the addition amount of the compound A is preferably 0.2 parts by mass or more, preferably 1 part by mass or more as the amount of phosphorus element. Is more preferable.
  • the upper limit is preferably 500 parts by mass or less, and more preferably 400 parts by mass or less. Thereby, the yield corresponding to the usage-amount of the compound A can be obtained efficiently. Therefore, 0.2 to 500 parts by mass is preferable, and 1 to 400 parts by mass is more preferable.
  • Compound B When reacting Compound A with cellulose raw material or defibrated cellulose fiber, Compound B may be further added to the reaction system.
  • Examples of the method of adding Compound B to the reaction system include a method of adding Compound B to a slurry of cellulose raw material or defibrated cellulose fiber, an aqueous solution of Compound A, or a slurry of cellulose raw material or defibrated cellulose fiber and Compound A. It is done.
  • Compound B is not particularly limited, but preferably exhibits basicity, more preferably a nitrogen-containing compound exhibiting basicity.
  • “Show basic” usually means that the aqueous solution of Compound B is pink to red in the presence of a phenolphthalein indicator, or / and the pH of the aqueous solution of Compound B is greater than 7.
  • the nitrogen-containing compound showing basicity is not particularly limited as long as the effects of the present invention are exhibited, but a compound having an amino group is preferable. Examples of the compound having an amino group include urea, methylamine, ethylamine, trimethylamine, triethylamine, monoethanolamine, diethanolamine, triethanolamine, pyridine, ethylenediamine, hexamethylenediamine and the like.
  • the amount of compound B added is preferably 2 to 1000 parts by mass, and more preferably 100 to 700 parts by mass.
  • the reaction temperature is preferably 0 to 95 ° C, more preferably 30 to 90 ° C.
  • the reaction time is not particularly limited, but is usually about 1 to 600 minutes, preferably 30 to 480 minutes. If the conditions for the esterification reaction are in any of these ranges, cellulose can be prevented from being excessively esterified and easily dissolved, and the yield of phosphorylated esterified cellulose can be improved. it can.
  • a suspension of esterified cellulose fiber or esterified cellulose nanofiber is usually obtained.
  • the suspension of esterified cellulose fiber or esterified cellulose nanofiber is dehydrated as necessary.
  • Heat treatment is preferably performed after dehydration. Thereby, hydrolysis of a cellulose raw material or a defibrated cellulose fiber can be suppressed.
  • the heating temperature is preferably 100 to 170 ° C. While water is included in the heat treatment, heating is performed at 130 ° C or less (more preferably 110 ° C or less), and after removing water, heating is performed at 100 to 170 ° C. More preferably, it is processed.
  • phosphate esterified cellulose In phosphate esterified cellulose, a phosphate group substituent is introduced into the cellulose, and the cellulose repels electrically. Therefore, the phosphate esterified cellulose fiber can be easily defibrated up to cellulose nanofibers (the defibration performed until the cellulose nanofibers are thus formed is also referred to as nano-defibration).
  • the phosphate group substitution degree per glucose unit of the phosphate esterified cellulose fiber is preferably 0.001 or more. Thereby, sufficient defibration (for example, nano defibration) can be implemented.
  • the upper limit of the degree of phosphate group substitution per glucose unit of the phosphate esterified cellulose fiber is preferably 0.40 or less.
  • the phosphate group substitution degree per glucose unit of the phosphate esterified cellulose fiber is preferably 0.001 to 0.40.
  • the degree of phosphate group substitution per glucose unit of cellulose nanofibers (phosphate esterified cellulose nanofibers) modified by phosphoric esterification is preferably 0.001 or more.
  • the upper limit is preferably 0.40 or less. Therefore, the phosphate group substitution degree per glucose unit of the phosphate esterified cellulose nanofiber is preferably 0.001 to 0.40. It is preferable that the phosphorylated cellulose fiber is subjected to a washing treatment such as washing with cold water after boiling. Thereby, defibration can be performed efficiently.
  • the reaction tank used in the step of chemically modifying this cellulose raw material to obtain modified cellulose is not particularly limited, but a tank provided with a stirring blade, a pulper, a kneader, a ribbon type mixing device, a screw type mixing An apparatus etc. can be illustrated.
  • a tank or a pulper provided with a stirring blade capable of stirring a liquid or liquid slurry it is preferable to use a tank or a pulper provided with a stirring blade capable of stirring a liquid or liquid slurry.
  • a kneader, ribbon type mixer, screw type mixer that can mix and agitate them is used. It is preferable to do.
  • the dispersion of chemically modified cellulose obtained in the chemical modification step of cellulose is a step of washing with water after the dehydration treatment.
  • a fiber dispersion can be obtained.
  • a centrifugal, vacuum dehydration or pressure dehydration type dehydration apparatus can be used. Specifically, basket-type centrifuges, decanter-type centrifuges, etc. as centrifugal separation types, drum-type vacuum dehydrators as vacuum dehydration types, horizontal belt filters, etc., filter presses, tube presses, screw presses as pressure dehydration types Belt press horizontal belt filter, poly disk filter, vibrating screen and the like.
  • pressure dehydration type filter press, tube press, screw press
  • centrifugal separation type basic type, decanter type
  • vacuum dehydration type Drum type vacuum dehydrator, horizontal belt filter
  • the concentration of the chemically modified cellulose dispersion is 2.5% by mass to 15% by mass, more preferably 3% by mass in order to efficiently perform the preliminary defibrating step. Adjust to ⁇ 10% by mass.
  • the amount is less than 0.5% by mass, the presence of the modified pulp is too small to efficiently defibrate.
  • it exceeds 15% by mass the viscosity of the chemically modified cellulose dispersion is too high to efficiently defibrate.
  • the apparatus used in the preliminary defibrating beating process is a single disk type refiner.
  • the single disc type refiner has high plate surface accuracy and can be operated with a narrow plate clearance. Carrying out the preliminary defibrating step (A) leads to loosening the outer layer of the cellulose fibers and fibrillation inside, so that cellulose nanofibers can be easily obtained in this defibrating step (B) and the load is reduced.
  • the treatment rate of chemically modified cellulose in a single disc type refiner is 30 m 3 / hr or less.
  • the treatment rate is 30 m 3 / hr or less.
  • the single disk type refiner includes a papermaking plate (viscous beating plate, fine bar type plate), a plate (plate with a dam) that closes the raw material flow path, and a grindstone plate. Any flat metal plate without grooves is used.
  • the plate clearance of the refiner used in the preliminary defibrating step (A) is 0.01 mm to 0.4 mm, more preferably 0.1 mm to 0.3 mm. If the thickness is less than 0.01 mm, the plate will be abruptly worn. If the thickness exceeds 0.4 mm, the clearance is too wide and the processing is difficult to proceed.
  • a conventional refiner that adjusts the clearance by moving the rotor side plate using a hydraulic or pneumatic jack may be used, but a ball screw type clearance adjustment mechanism is more preferable.
  • the use of a refiner with a squeezer and further precise control of the clearance between the plates by means of a laser position measurement mechanism or the like enables efficient pre-defibration.
  • the peripheral speed of the plate is preferably 24.5 m / s or more, more preferably 30 m / s or more. By setting the peripheral speed of the plate to 24.5 m / s or more, preliminary defibration can be performed efficiently.
  • the rotational shear rate of the refiner plate is 100 (1 / ms) or more, more preferably 150 (1 / ms) or more.
  • the rotational shear rate of the plate (the peripheral speed of the plate / plate clearance).
  • the rotational shear rate of the plate is less than 100 (1 / ms)
  • preliminary defibration cannot be performed efficiently.
  • a normal head case-shaped refiner may be used, but in order to prevent heat generation due to stirring of the raw material staying inside the head case, the space inside the head case is 10 L or less. It is better to do.
  • a cooling water jacket for cooling the pulp is installed in the space inside the head case so that the treatment is performed while suppressing the influence of heat on the pulp.
  • the present defibration means that cellulose obtained by preliminary defibration is applied with a strong shearing force using a high-pressure disperser, and an average fiber length of 0.5 to 5 ⁇ m and an average fiber width of 3 to Defibration up to 100 nm.
  • a wet high-pressure or ultrahigh-pressure homogenizer that can apply a pressure of 1 MPa to 400 MPa to the chemically modified cellulose dispersion and can apply a strong shearing force.
  • a wet high-pressure or ultrahigh-pressure homogenizer that can apply a pressure of 10 MPa to 400 MPa and a strong shear force to the chemically modified cellulose dispersion is preferably used.
  • the chemically modified cellulose is defibrated to form cellulose nanofibers, and the cellulose nanofibers are dispersed in the medium to produce a cellulose nanofiber dispersion.
  • AFM atomic force microscope
  • Example 1 Pulp raw material adjustment: oxidized pulp
  • Bleached unbeaten pulp (Nippon Paper Co., Ltd.) 5 g (absolutely dried) derived from coniferous trees, TEMPO (Tokyo Kasei Co., Ltd.) 78 mg (0.5 mmol) and sodium bromide (Wako Pure Chemical Industries, Ltd.) 756 mg (7.35 mmol) )
  • TEMPO Tokyo Kasei Co., Ltd.
  • sodium bromide Wi-Fi Pure Chemical Industries, Ltd.
  • sodium hypochlorite manufactured by Wako Pure Chemical Industries, Ltd.
  • a liquid feed pump was added so that sodium hypochlorite was added at a rate of 0.23 mmol / min per gram of pulp.
  • the addition was continued until the total amount of sodium hypochlorite added was 22.5 mmol.
  • the pH in the system was lowered, but a 3N sodium hydroxide aqueous solution was successively added to adjust the pH to 10.
  • reaction time was taken as the reaction time.
  • the reaction solution was neutralized with hydrochloric acid until neutral, and then the reaction solution was filtered through a glass filter and sufficiently washed with water to obtain an oxidized pulp.
  • the carboxyl group amount of oxidized pulp was measured by the following method. Prepare 60 mL of 0.5% by mass slurry of oxidized pulp, add 0.1 M hydrochloric acid aqueous solution to pH 2.5, then add 0.05 N aqueous sodium hydroxide solution dropwise until the pH reaches 11 was calculated from the amount (a) of sodium hydroxide consumed in the neutralization step of the weak acid where the change in electrical conductivity was gradual, using the following equation.
  • Amount of carboxyl group [mmol / g oxidized pulp] A [mL] x 0.05 / oxidized pulp mass [g]
  • the carboxyl group content of the obtained oxidized pulp was 1.60 mmol / g.
  • the slurry of oxidized pulp that had undergone the above oxidation treatment was subjected to a preliminary defibration treatment using a single disk type refiner made by Aikawa Tekko.
  • a fine bar type plate was used, and the shape of the plate blade was a blade width of 0.8 mm, a groove width of 1.5 mm, a blade length of 90 mm, a blade angle of 15 °, and a plate clearance of 0.1 mm.
  • the processing speed of the preliminary defibrating by the refiner is 1 m 3 / hr, the raw material concentration of the oxidized pulp slurry used for the preliminary defibrating processing is 3% (w / v), and the peripheral speed of the refiner plate is 40.2 m / s.
  • the rotational shear rate of the plate was 402.0 (1 / ms), and the number of refiner passes was 1. As a result, the preliminary defibrating treatment could be operated without any problems.
  • the power consumption of preliminary defibration was 0.76 kWh / kg.
  • Example 2 Among the experimental conditions of Example 1, the plate is a dam formed on the outer periphery of a fine bar type plate, and the shape of the plate blade is a blade width of 0.8 mm, a groove width of 1.0 mm, a blade length of 80 mm,
  • the experiment was performed under the same conditions as those of Example 1 except that the blade angle was changed to 15 ° and the treatment speed was changed to 3 m 3 / hr. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.17 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 44.5%.
  • Example 3 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the plate was changed to a grindstone plate (no blade) and the processing speed was changed to 3 m 3 / hr. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.18 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 44.1%.
  • Example 4 Of the experimental conditions of Example 1, the plate is a viscous beating plate, and the shape of the plate blade is a blade width of 4.5 mm, a groove width of 3.5-4.5 mm, a blade length of 95 mm, and a blade angle of 10 °.
  • the plate clearance is 0.13 mm
  • the processing speed is 19.2 m 3 / hr
  • the plate peripheral speed is 24.6 m / s
  • the rotational shear rate of the plate is 189.2 (1 / ms)
  • the experiment was performed under the same conditions as in Example 1 except that the number of treatments was set to 3. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.03 kWh / kg
  • the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 52.3%.
  • Example 5 Of the experimental conditions of Example 1, the plate is of the dam type (3-stage dam), and the shape of the plate blade is 4.0 mm blade width, 4.0 mm groove width, 75-85 mm blade length, and 0 ° blade angle.
  • the processing speed was 9.0 m 3 / hr
  • the peripheral speed of the plate was 24.6 m / s
  • the rotational shear rate of the plate was 246.0 (1 / ms)
  • the number of processing by the refiner was 2.
  • the experiment was performed under the same conditions as in Example 1 except for the above. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.05 kWh / kg
  • the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 51.6%.
  • Example 6 Among the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the raw material concentration was changed to 5 percent. As a result, it was possible to operate without problems in both the preliminary defibrating process and the main defibrating process.
  • the power consumption of preliminary defibration was 0.65 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 69.0%.
  • Example 7 Among the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was changed to 3 m 3 / hr. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.25 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 54.6%.
  • Example 8 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was changed to 3 m 3 / hr and the raw material concentration was changed to 5%. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.28 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 63.3%.
  • Example 9 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was changed to 9 m 3 / hr. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.07 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 52.7%.
  • Example 10 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was changed to 9 m 3 / hr and the raw material concentration was changed to 5%. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.08 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 63.5%.
  • Example 11 Of the experimental conditions of Example 1, the processing speed was 15 m 3 / hr, the plate peripheral speed was 24.6 m / s, the rotational shear rate of the plate was 246.0 (1 / ms), and the number of processing by the refiner was 3.
  • the experiment was performed under the same conditions as in Example 1 except that. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.03 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 57.3%.
  • Example 12 Of the experimental conditions of Example 1, the plate clearance was 0.08 mm, the processing speed was 23.4 m 3 / hr, the plate peripheral speed was 30.7 m / s, and the rotational shear rate of the plate was 383.8 (1 / ms).
  • the experiment was performed under the same conditions as in Example 1 except that the number of treatments by the refiner was set to 8. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.03 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 63.3%.
  • Example 13 Among the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the raw material concentration was changed to 7%. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.45 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 70.0%.
  • Example 14 Of the experimental conditions of Example 1, the processing speed was 3 m 3 / hr, the plate peripheral speed was 55.8 m / s, and the rotational shear rate of the plate was changed to 558.0 (1 / ms). The experiment was performed under the same conditions as the experimental conditions. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.57 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 67.3%.
  • Example 15 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was 9 m 3 / hr, the raw material concentration was 10%, and the number of treatments by the refiner was 3. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.12 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 60.2%.
  • Example 16 Of the experimental conditions of Example 1, the plate clearance was 0.22 mm, the processing speed was 11.6 m 3 / hr, the raw material concentration was 5%, the plate peripheral speed was 30.7 m / s, and the rotational shear rate of the plate was 139.
  • the experiment was performed under the same conditions as those of Example 1 except that 5 (1 / ms) and the number of treatments by the refiner were set to 4. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.29 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 68.0%.
  • Table 1 shows refiner conditions, power consumption, and experimental results of Examples 1 to 16.
  • Example 3 Of the experimental conditions of Example 1, the experiment was performed under the same conditions as those of Example 1 except that the treatment speed was 40 m 3 / hr and the number of treatments by the refiner was 3. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems.
  • the power consumption of preliminary defibration was 0.07 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg.
  • the transparency of the obtained cellulose nanofiber dispersion was 33%, which was low.
  • Example 4 Among the experimental conditions of Example 1, the preliminary defibration was performed under the same conditions as the experimental conditions of Example 1 except that the raw material concentration was 16% and the number of treatments by the refiner was 3, but the viscosity of the sample was high. The operability was poor and the preliminary defibration was not possible.
  • Example 5 Of the experimental conditions of Example 1, the plate peripheral speed is 15 m / s, the rotational shear rate of the plate is 150.0 (1 / ms), and the number of treatments by the refiner is 3, and the same as the experimental conditions of Example 1. The experiment was conducted under conditions. In this case, both the preliminary defibration and the main defibration processes could be operated without any problems. The power consumption of preliminary defibration was 1.8 kWh / kg, and the power consumption of this defibration was 1.8 kWh / kg. Further, the transparency of the obtained cellulose nanofiber dispersion was 35.2%, which was low.
  • Table 2 shows the refiner conditions, power consumption, and experimental results of Comparative Examples 1 to 5.
  • Examples 1 to 16 high-quality cellulose nanofiber dispersions with low power consumption and high transparency could be produced. Further, the operability of the preliminary defibration and the main defibration was good, and the clogging of the dispersion nozzle did not occur. Furthermore, the number of preliminary defibration and the number of passes of ultrahigh pressure homo may be appropriately adjusted according to the required transparency.
  • Comparative Example 1 On the other hand, in Comparative Example 1, clogging occurred in the dispersion nozzle in this defibrating process, resulting in poor operability. Further, the transparency of the obtained cellulose nanofiber dispersion was lower than that of Examples 1 to 16. In Comparative Example 2, a metal touch occurred and preliminary defibration could not be performed. In Comparative Example 3, the transparency of the obtained cellulose nanofiber dispersion was lower than that in Examples 1-16. In Comparative Example 4, the viscosity of the sample was too high, the operability was poor, and preliminary defibration could not be performed. In Comparative Example 5, the transparency of the obtained cellulose nanofiber dispersion was lower than that in Examples 1-16.

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Abstract

Ce procédé de production d'une dispersion de nanofibres de cellulose à transparence élevée comprend une étape de défibrage préliminaire pour battre la cellulose chimiquement modifiée à l'aide d'un raffineur de type à disque unique, et une étape de défibrage principal pour défibrer la pâte obtenue dans l'étape de défibrage préliminaire par traitement par un dispositif de dispersion haute pression à une pression de traitement de 1 à 400 MPa.
PCT/JP2019/006001 2018-03-14 2019-02-19 Procédé de production d'une dispersion de nanofibres de cellulose WO2019176465A1 (fr)

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CN114075796B (zh) * 2020-08-20 2022-12-16 华南理工大学 一种植物基纤维素纳米纤丝及其制备方法与应用

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