JP2011012134A - Method for producing low crystalline cellulose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method with excellent productivity by which low crystalline cellulose having lowered cellulose I crystallinity is efficiently obtained while suppressing reduction in molecular weight.SOLUTION: The method for producing low crystalline cellulose includes crushing a cellulose-containing raw material, in which a cellulose content in a residual component except water is ≥20 mass%, the following cellulose I crystallinity exceeds 33%, a molecular weight of cellulose is 100,000-1,000,000, and a water content is ≤4.5 mass%, with a crusher, so that the cellulose I crystallinity is lowered to 1/2.5 to 1/100 after the crushing: cellulose I crystallinity (%)=[(I-I)/I]×100, wherein Idenotes diffraction intensity of a lattice plane (002 plane) (2θ=22.6°) in X-ray diffraction; and Idenotes diffraction intensity of an amorphous moiety (2θ=18.5°).

Description

  The present invention relates to a method for producing low crystalline cellulose.

Cellulose obtained by pulverizing cellulose-containing raw materials such as pulp is used as industrial raw materials such as cellulose ether raw materials, cosmetics, foods, and biomass materials. As these industrial raw materials, cellulose having an amorphous cellulose crystal structure is particularly useful.
As a method for reducing the crystallinity of cellulose, a method of mechanically treating a cellulose-containing raw material with a pulverizer is known (see, for example, Patent Documents 1 to 4).
Examples 1 to 3 of Patent Document 1 include a method of treating pulp with a ball mill, and Examples 1 and 2 of Patent Document 2 include cellulose powder obtained by chemical treatment such as hydrolysis of pulp. Are each disclosed in a ball mill or an airflow type pulverizer. However, these methods are not satisfactory in efficiency and productivity in reducing the crystallinity of cellulose.
In Patent Documents 3 and 4, a cellulose-containing raw material having a bulk density of 100 to 500 kg / m ³ is treated with a pulverizer filled with balls or rods, so that the cellulose I type crystallinity is 33% or less. A method for producing cellulose is disclosed. However, development of a method for more efficiently reducing the crystallinity of cellulose is desired.
Furthermore, since the cellulose obtained by mechanical treatment as described above decreases in molecular weight (or degree of polymerization) as well as in crystallinity, for example, Patent Document 5 discloses an alkaline aqueous solution in which the degree of polymerization of cellulose does not excessively decrease. For the purpose of obtaining soluble cellulose, a method is disclosed in which a non-crystallized cellulose having a degree of crystallinity of 35% or less is steamed in pressurized steam and then blasted. In Examples 1 and 4, a sheet-like pulp is used. A method of performing an amorphous treatment to a crystallinity of 35% or less using a vibrating ball mill or a twin screw extruder is disclosed. However, efficiency and productivity are not satisfactory in achieving both reduction in the crystallinity of cellulose and suppression of reduction in molecular weight.

JP 2003-64184 A JP 2004-331918 A Japanese Patent No. 4160108 Japanese Patent No. 4160109 JP 62-236801 A

  The present invention provides a production method excellent in productivity, capable of efficiently obtaining low crystalline cellulose having a reduced cellulose I-type crystallinity while suppressing a decrease in molecular weight from a cellulose-containing raw material. This is the issue.

  The present inventors have found that the above problem can be solved by treating a cellulose-containing raw material having a water content of 4.5% by mass or less with a pulverizer.

That is, in the present invention, the cellulose content in the remaining components excluding water from the cellulose-containing raw material is 20% by mass or more, and the cellulose I type crystallinity of the cellulose represented by the following calculation formula (1) exceeds 33%. The cellulose-containing raw material having a cellulose molecular weight of 100,000 to 1,000,000 and a water content of 4.5% by mass or less is processed by a pulverizer, and the cellulose I-type crystallinity is reduced by half before and after the pulverization process. A method for producing low crystalline cellulose, which is reduced to 5 to 1/100.
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] × 100 (1)
[I _22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the diffraction intensity of the amorphous portion (diffraction angle 2θ = 18.5 °). Show

  The method for producing low crystalline cellulose of the present invention is excellent in productivity, and can efficiently obtain low crystalline cellulose having a reduced cellulose I-type crystallinity while suppressing a decrease in molecular weight from a cellulose-containing raw material. it can.

In the present invention, the cellulose content in the remaining components excluding water from the cellulose-containing raw material is 20% by mass or more, the cellulose type I crystallinity of the cellulose represented by the following calculation formula (1) exceeds 33%, cellulose A cellulose-containing raw material having a molecular weight of 100,000 to 1,000,000 and a water content of 4.5% by mass or less is processed by a pulverizer, and the cellulose I-type crystallinity is 1 / 2.5 before and after the pulverization process. It is a manufacturing method of low crystalline cellulose reduced to ˜1 / 100.
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] × 100 (1)
[I _22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the diffraction intensity of the amorphous portion (diffraction angle 2θ = 18.5 °). Show
Hereinafter, in this specification, the cellulose type I crystallinity of cellulose is sometimes simply referred to as “crystallinity”.

[Cellulose-containing raw material]
The cellulose-containing raw material used in the present invention has a cellulose content in the remaining components excluding water from the raw material of 20% by mass or more, preferably 40% by mass or more, more preferably 60% by mass or more.
The cellulose content in the present invention means the total amount of cellulose and hemicellulose.
The cellulose-containing raw material is not particularly limited, and various wood chips, various tree pruned branches, thinned wood, branch timber, building waste, factory waste, etc .; wood pulp produced from wood, cotton seeds Pulp such as cotton linter pulp obtained from surrounding fibers; Paper such as newspaper, corrugated cardboard, magazines and fine paper; Plant stems and leaves such as rice straw and corn stalks; Plants such as rice husk, palm husk and coconut husk Shells and the like. Among these, pulps, woods and papers are preferable, and pulps and papers are more preferable.
In the case of commercially available pulp, the cellulose content in the remaining components excluding water is usually 75 to 99% by mass, and includes lignin and the like as other components.

[Cellulose type I crystallinity]
The cellulose type I crystallinity of the cellulose in the present invention is calculated by the Segal method from the diffraction intensity value by the X-ray diffraction method, and is defined by the following calculation formula (1).
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] × 100 (1)
[I _22.6 is the diffraction intensity of the grating plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the diffraction intensity of the amorphous portion (diffraction angle 2θ = 18.5 °). ]

  The low crystalline cellulose produced by the present invention has a cellulose I type crystallinity reduced preferably to 33% or less. If the degree of crystallinity is 33% or less, the chemical reactivity of cellulose is improved. For example, in the production of cellulose ether, alkali celluloseization easily proceeds when an alkali is added, resulting in cellulose etherification reaction. The reaction conversion rate can be improved. In this respect, the degree of crystallinity is preferably 20% or less, more preferably 15% or less, still more preferably 10% or less, and particularly preferably 1 to 7%. Note that the cellulose I type crystallinity defined by the calculation formula (1) may be a negative value in calculation, but in the case of a negative value, the cellulose I type crystallinity is 0%.

  Here, the cellulose I type crystallinity is the ratio of the amount of crystal region of cellulose to the total amount. Cellulose type I is a crystalline form of natural cellulose. The degree of crystallinity is also related to the physical and chemical properties of cellulose, and the larger the value, the higher the crystallinity of cellulose and the less non-crystalline parts, so the hardness, density, etc. increase, but elongation, flexibility, Solubility and chemical reactivity in water and solvent decrease. The cellulose I type crystallinity of commercially available pulp is usually 60% or more.

[Production of low crystalline cellulose]
In the present invention, the cellulose-containing raw material having a water content of 4.5% by mass or less is processed by a pulverizer, and the cellulose I-type crystallinity is reduced to 1 / 2.5 to 1/100 before and after the pulverization process. A low crystalline cellulose is produced by reducing the amount (hereinafter, the pulverization process is referred to as “low crystallization process”).
The water content in the cellulose-containing raw material used for the low crystallization treatment in the present invention is 4.5% by mass or less, preferably 4.3% by mass or less, more preferably 4% by mass or less, and 3.5% by mass or less. More preferred is 3% by mass or less. If this water content is 4.5% by mass or less, it can be easily pulverized, and the low crystallization speed by the pulverization treatment can be improved, and the crystallinity can be reduced efficiently in a short time. A decrease in molecular weight due to pulverization can be suppressed. On the other hand, the lower limit of the moisture content is preferably 0.2% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.4% by mass or more from the viewpoint of productivity.
From the above viewpoint, the water content in the cellulose-containing raw material used for the low crystallization treatment is preferably 0.2 to 4.3% by mass, more preferably 0.3 to 4% by mass, and 0.4 to 3.5. % By mass is more preferable, and 0.4 to 3% by mass is particularly preferable.

The bulk density of the cellulose-containing raw material used for the low crystallization treatment in the present invention is preferably 50 to 500 kg / m ³ .
When the bulk density is 50 kg / m ³ or more, the cellulose-containing raw material has an appropriate volume, and thus handleability is improved. In addition, since the amount of raw material charged into the pulverizer can be increased, the processing capacity is improved, and pulverization and low crystallization can be performed more efficiently. From this viewpoint, the above bulk density is more preferably 65 kg / m ³ or more, and further preferably 100 kg / m ³ or more. On the other hand, the upper limit of the bulk density is preferably 500 kg / m ³ or less, more preferably 400 kg / m ³ or less, and still more preferably 350 kg / m ³ or less from the viewpoint of handleability and productivity. From these viewpoints, the above bulk density is more preferably 65 to 400 kg / m ³ , and still more preferably 100 to 350 kg / m ³ . In addition, said bulk density can be measured by the method as described in an Example.

The cellulose molecular weight of the cellulose-containing raw material supplied to the pulverizer is in the range of 100,000 to 1,000,000. When the molecular weight of the cellulose is in the above range, efficient low crystallization is possible. From these viewpoints, the molecular weight of cellulose is more preferably 120,000 to 750,000, and further preferably 150,000 to 600,000. In addition, the molecular weight of said cellulose can be measured by the method as described in an Example.
By treating the cellulose-containing raw material with a pulverizer, the cellulose-containing raw material is pulverized, and the low-crystalline cellulose having a reduced crystallinity is effectively suppressed in a short time while suppressing a decrease in the molecular weight of the cellulose. Can be manufactured.

(Pretreatment for low crystallization treatment)
Preprocess if the bulk density is the cellulose-containing raw material or surface area of less than 50 kg / m ³ is more than 100 cm ^2, a bulk density 50~500kg / m ^3, or the surface area in the range of 0.01～100Cm ² It is preferable to adjust. For example, as a pretreatment of the cellulose-containing raw material, the bulk density, the surface area, and the specific surface area of the cellulose-containing raw material can be set to the above-described preferable ranges by performing a cutting treatment and / or a crushing treatment. From the viewpoint of producing low crystalline cellulose with a small number of steps, it is preferable to perform a cutting treatment as a pretreatment of the cellulose-containing raw material.

(Cutting process)
The method for cutting the cellulose-containing raw material can be selected as appropriate depending on the type and shape of the cellulose-containing raw material. For example, a method using one or more cutting machines selected from a shredder, a slitter cutter, and a rotary cutter. Is mentioned.
When using a sheet-like cellulose-containing raw material, it is preferable to use a shredder or a slitter cutter as a cutter, and it is more preferable to use a slitter cutter from the viewpoint of productivity.
The slitter cutter is cut vertically with a roll cutter in the longitudinal direction along the longitudinal direction of the sheet to form a long and narrow strip, and then cut shortly along the width direction of the sheet with a fixed blade and a rotary blade, A cellulose-containing raw material having a shape can be easily obtained. As the slitter cutter, a sheet pelletizer manufactured by Horai Co., Ltd. can be preferably used. When this apparatus is used, a sheet-like cellulose-containing raw material can be cut into about 1 to 20 mm square.

  It is preferable to use a rotary cutter when cutting wood such as thinned wood, pruned branches, construction waste, etc., or cellulose-containing raw materials other than sheets. The rotary cutter is composed of a rotary blade and a screen, and can easily obtain a cellulose-containing raw material that is cut by the rotary blade below the opening of the screen. In addition, if necessary, a fixed blade may be provided and cutting may be performed with a rotary blade and a fixed blade.

  When a rotary cutter is used, the size of the coarsely pulverized product obtained can be controlled by changing the opening of the screen. The screen opening is preferably 1 to 70 mm, more preferably 2 to 50 mm, and even more preferably 3 to 40 mm. If the opening of the screen is 1 mm or more, a coarsely pulverized product having an appropriate bulkiness is obtained, and the handleability is improved. If the opening of the screen is 70 mm or less, the subsequent pulverization process has an appropriate size as a pulverization raw material, and thus the load can be reduced.

  The size of the cellulose-containing raw material obtained after the cutting treatment is preferably 1 to 70 mm square, more preferably 1 to 50 mm square. By cutting into 1 to 70 mm square, the subsequent drying process can be performed efficiently and easily, and the load required for the pulverization in the subsequent pulverization process can be reduced.

(Crushing treatment)
Next, the cellulose-containing raw material, preferably the cellulose-containing raw material obtained by the above-described cutting treatment, can be further crushed as necessary. As the crushing treatment, an extruder treatment is preferable. By the extruder treatment, a compressive shear force can be applied, the crystal structure of cellulose can be destroyed, the cellulose-containing raw material can be pulverized, and the bulk density can be further increased.
As a method of mechanically pulverizing by applying a compressive shear force, conventionally used impact type pulverizers such as a cutter mill, a hammer mill, a pin mill, etc., make the pulverized material fluffy and bulky. And the mass-based throughput is reduced. On the other hand, by using an extruder, a pulverized raw material having a desired bulk density can be obtained, and handleability can be improved.

The extruder may be either a single-screw type or a twin-screw type, but a twin-screw extruder is preferable from the viewpoint of increasing the conveyance capability.
The twin screw extruder is an extruder in which two screws are rotatably inserted into a cylinder, and conventionally known ones can be used. The rotation directions of the two screws may be the same or opposite directions, but the rotation in the same direction is preferable from the viewpoint of increasing the conveyance capability.
Further, as the meshing conditions of the screw, any of full-engagement, partial meshing, and non-meshing extruders may be used, but from the viewpoint of improving the processing capability, the complete meshing type and the partial meshing type are preferable.

As an extruder, it is preferable to provide what is called a kneading disk part in any part of a screw from a viewpoint of applying a strong compressive shear force.
The kneading disc part is composed of a plurality of kneading discs, which are continuously combined at a constant phase, for example, 90 °, and are kneaded as the screw rotates. By forcing the cellulose-containing raw material to pass through a narrow gap between the disks or between the kneading disk and the cylinder, an extremely strong shearing force can be applied. As a configuration of the screw, it is preferable that the kneading disk portion and the plurality of screw segments are alternately arranged. In the case of a twin screw extruder, it is preferable that the two screws have the same configuration.

As a method of the coarse crushing treatment, a method of continuously processing the cellulose-containing raw material, preferably the cellulose-containing raw material obtained by the cutting treatment is put into an extruder. The shear rate is preferably 10 sec ^-1 or more, more preferably 20～30000Sec ^-1, more preferably 50~3000sec ^-1, 500~3000sec ^-1 is particularly preferred. If the shear rate is 10 sec ⁻¹ or more, pulverization proceeds effectively. Other treatment conditions are not particularly limited, but the treatment temperature is preferably 5 to 200 ° C.
Also, as the number of passes by the extruder, a sufficient effect can be obtained even with one pass, but from the viewpoint of reducing the crystallinity and the degree of polymerization of cellulose, if one pass is insufficient, perform two or more passes. Is preferred. Further, from the viewpoint of productivity, 1 to 10 passes is preferable. By repeating the pass, coarse particles are pulverized and a powdery cellulose-containing raw material with little variation in particle size can be obtained. When performing two or more passes, in consideration of production capacity, a plurality of extruders may be arranged in series for processing.

  The average particle size of the cellulose-containing raw material obtained after the coarse pulverization treatment is preferably in the range of 0.01 to 1 mm from the viewpoint of efficiently dispersing the pulverized raw material in the pulverizer in the low crystallization treatment. If the average particle diameter is 1 mm or less, the pulverized raw material can be efficiently dispersed in the pulverizer during the low crystallization treatment, and the predetermined particle diameter can be reached without taking a long time. it can. On the other hand, the lower limit of the average particle diameter is preferably 0.01 mm or more from the viewpoint of productivity. From these viewpoints, the average particle diameter is more preferably 0.01 to 0.7 mm, and even more preferably 0.05 to 0.5 mm. In addition, said average particle diameter can be measured by the method as described in an Example.

(Drying process)
In the present invention, the cellulose-containing raw material, preferably the cellulose-containing raw material obtained by the above-described cutting treatment and / or crushing treatment, is preferably dried before the low crystallization treatment.
In general, commercially available pulps, papers used as biomass resources, woods, plant stems / leaves, plant shells and other generally available cellulose-containing raw materials contain more than 5% by weight of moisture. Usually, it contains about 5 to 30% by mass of water.
Therefore, in this invention, it is preferable to adjust the moisture content of a cellulose containing raw material to 4.5 mass% or less by performing a drying process.

As a drying method, a known drying means may be appropriately selected. For example, hot air heat receiving drying method, conductive heat receiving drying method, dehumidified air drying method, cold air drying method, microwave drying method, infrared drying method, sun drying method , Vacuum drying method, freeze drying method and the like.
In the above drying method, a known dryer can be appropriately selected and used. For example, “Introduction to Powder Engineering” (Edited by Japan Powder Industry Technology Association, Powder Technology Information Center 1995) page 176 And the like.
These drying methods and dryers may be used alone or in combination of two or more. The drying process can be either a batch process or a continuous process.
The temperature in the drying process cannot be determined unconditionally depending on the drying means, drying time, etc., but is preferably 10 to 250 ° C, more preferably 50 to 150 ° C. As processing time, 0.01-2 hr is preferable and 0.02-1 hr is more preferable. You may dry-process under reduced pressure as needed, and as a pressure, 1-120 kPa is preferable and 50-105 kPa is more preferable.

[Low crystallization treatment]
As the pulverizer used for the low crystallization treatment, a medium pulverizer can be preferably used. The medium type pulverizer includes a container driven pulverizer and a medium stirring pulverizer.
Examples of the container-driven crusher include a rolling mill, a vibration mill, a planetary mill, and a centrifugal fluid mill. Among these, a vibration mill is preferable from the viewpoint of high grinding efficiency and productivity.
As a medium agitation type pulverizer, a tower type pulverizer such as a tower mill; an agitating tank type pulverizer such as an attritor, an aquamizer, a sand grinder; a distribution tank type pulverizer such as a visco mill and a pearl mill; For example, a continuous dynamic type pulverizer. Among these, a stirring tank type pulverizer is preferable from the viewpoint of high pulverization efficiency and productivity. In the case of using a medium stirring pulverizer, the peripheral speed of the tip of the stirring blade is preferably 0.5 to 20 m / s, more preferably 1 to 15 m / s.
The type of pulverizer can be referred to “Chemical Engineering Advances 30th Particulate Control” (Chemical Engineering Society, Tokai Branch, issued October 10, 1996, Sakai Shoten).
The processing method may be either batch processing or continuous processing, but continuous processing is preferable from the viewpoint of productivity.

Examples of the pulverizer medium include balls, rods, and tubes. Of these, balls and rods are preferable and rods are more preferable from the viewpoint of high grinding efficiency and productivity.
There is no restriction | limiting in particular as a material of the medium of a grinder, For example, iron, stainless steel, an alumina, a zirconia, silicon carbide, a silicon nitride, glass etc. are mentioned.

  When the pulverizer is a vibration mill and the medium is a ball, the outer diameter of the ball is preferably in the range of 0.1 to 100 mm, more preferably 0.5 to 50 mm. If the size of the ball is in the above range, the desired pulverization force can be obtained, and the cellulose-containing raw material can be efficiently contaminated without contamination of the cellulose-containing raw material by mixing pieces of the ball, etc. The crystallinity can be reduced.

In the present invention, pulverization with a vibration mill filled with a rod is preferable because the crystallinity can be efficiently reduced while suppressing a decrease in the molecular weight of cellulose in the raw material.
As a vibration mill, a vibration mill manufactured by Chuo Kakki Co., Ltd., a small vibration rod mill 1045 type manufactured by Yoshida Seisakusho Co., Ltd., a vibration cup mill P-9 type manufactured by Fritsch, Germany, and a small vibration mill manufactured by Nichito Kagaku Co., Ltd. An NB-O type or the like can be used.
The rod used as the medium of the pulverizer is a rod-shaped medium, and a rod having a cross section of a polygon such as a quadrangle or a hexagon, a circle, or an ellipse can be used.
The outer diameter of the rod is preferably in the range of 0.5 to 200 mm, more preferably 1 to 100 mm, and still more preferably 5 to 50 mm. The length of the rod is not particularly limited as long as it is shorter than the length of the pulverizer container. If the size of the rod is in the above range, the desired pulverization force can be obtained, and while the fragment of the rod is mixed and the cellulose-containing raw material is not contaminated, the decrease in the molecular weight of the cellulose is efficiently suppressed. The crystallinity can be reduced.

The filling ratio of the medium such as balls and rods varies depending on the type of pulverizer, but is preferably 10 to 97%, more preferably 15 to 95%. When the filling rate is within this range, the contact frequency between the cellulose-containing raw material and the medium is improved, and the grinding efficiency can be improved without hindering the movement of the medium. Here, the filling rate refers to the apparent volume of the medium relative to the volume of the stirring unit of the pulverizer.
The processing time of the pulverizer cannot be determined unconditionally depending on the type of pulverizer, the type of media such as balls and rods, size and filling rate, etc. From the viewpoint of efficiently reducing the pH, it is preferably 0.5 to 100 minutes, more preferably 2 to 80 minutes, still more preferably 3 to 60 minutes, and particularly preferably 3 to 40 minutes.
The treatment temperature is not particularly limited, but is preferably 5 to 250 ° C, more preferably 10 to 200 ° C, from the viewpoint of preventing deterioration of cellulose due to heat.

The crystallinity can be lowered while suppressing a decrease in molecular weight by the above treatment method, and the pulverized product does not adhere to the inside during the pulverization treatment, and the dry treatment can be performed.
The crystallinity ratio before and after the low crystallization treatment [crystallinity after treatment / crystallinity before treatment] (hereinafter sometimes simply referred to as crystallinity ratio) is 1 / 2.5 to 1/100, preferably 1 / 2.7 to 1/95, and more preferably 1/3 to 1/90.
The molecular weight of the obtained low crystalline cellulose is preferably 10,000 to 800,000, more preferably 3 from the viewpoint that, for example, cellulose ether having excellent usability can be obtained when cellulose ether is produced. It is 10,000 to 600,000, more preferably 50,000 to 500,000.
Further, from the same viewpoint as described above, the molecular weight ratio before and after the low crystallization treatment (molecular weight reduction rate) [molecular weight after treatment / molecular weight before treatment] (hereinafter sometimes simply referred to as molecular weight ratio) It is preferably 0.55 or more and less than 1, more preferably 0.60 or more and less than 1.
Furthermore, the molecular weight ratio / crystallinity ratio is preferably 9 to 20, more preferably 9 to 18, and further preferably 9 to 15 from the viewpoint of suppressing the decrease in the molecular weight ratio with respect to the rate of decrease in the crystallinity. preferable.
The average particle size of the obtained low crystalline cellulose is preferably from 1 to 150 μm, more preferably from 5 to 100 μm, and even more preferably from 7 to 100 μm, from the viewpoint of chemical reactivity and handleability when this is used as an industrial raw material. is there. In particular, when the average particle size is 7 μm or more, it is possible to suppress the occurrence of “maco” when the low crystalline cellulose is brought into contact with a liquid such as water.

The bulk density, molecular weight, average particle diameter, crystallinity, water content, and cellulose content of the cellulose-containing raw material and low crystalline cellulose were measured by the methods described below.
(1) Measurement of bulk density The bulk density was measured using "Powder Tester" manufactured by Hosokawa Micron Corporation. The measurement was calculated by vibrating the sieve, dropping the sample through a chute, receiving it in a specified container (capacity 100 mL), and measuring the mass of the sample in the container. However, the cotton-like sample was calculated by dropping it through a chute without passing through a sieve, receiving it in a specified container (capacity 100 mL), and measuring the mass of the sample in the container.
(2) Measurement of molecular weight of cellulose The molecular weight of cellulose was calculated by obtaining the degree of polymerization by the copper ammonia method described in ISO-4312 method and multiplying by the molecular weight of the glucose unit (162).
(3) Measurement of average particle diameter The average particle diameter was measured using a laser diffraction / scattering particle size distribution measuring apparatus “LA-920” (manufactured by Horiba, Ltd.). The measurement conditions were ultrasonic treatment for 1 minute before particle size measurement, water was used as a dispersion medium during measurement, and the volume-based median diameter was measured at a temperature of 25 ° C.

(4) Calculation of crystallinity The cellulose I type crystallinity is calculated by measuring the X-ray diffraction intensity of a sample using the “Rigaku RINT 2500VC X-RAY diffractometer” manufactured by Rigaku Corporation under the following conditions. Calculated based on the formula.
The measurement conditions were X-ray source: Cu / Kα-radiation, tube voltage: 40 kv, tube current: 120 mA, measurement range: diffraction angle 2θ = 5-45 °, and X-ray scan speed: 10 ° / min. The measurement sample was prepared by compressing a pellet having an area of 320 mm ² × thickness of 1 mm.
(5) Measurement of moisture content The moisture content was measured at 120 ° C using an infrared moisture meter (manufactured by Shimadzu Corporation, "MOC-120H").
(6) Measurement of cellulose content Cellulose content is described in pages 1081 to 1082 of the Japan Analytical Chemistry Society, Analytical Chemistry Handbook (4th revised edition, published on November 30, 1991, Maruzen Co., Ltd.). This was measured by the holocellulose quantitative method.

Example 1
[Cutting]
As a cellulose-containing raw material, a sheet-like wood pulp [“Biofloc HV-10A” manufactured by Tenbeck Co., Ltd., 800 mm × 600 mm × 1.0 mm, crystallinity 81.5%, cellulose content (residuals obtained by removing water from the cellulose-containing raw material] The content in the components (hereinafter the same) 96 mass%, water content 8.5 mass%] was applied to a sheet pelletizer (“SG (E) -220” manufactured by Horai Co., Ltd.), and about 4 mm × 4 mm × 1. It cut | judged to the magnitude | size of 0 mm. The pulp obtained after the cutting treatment had a bulk density of 200 kg / m ³ .

[Drying treatment]
The pulp obtained by the cutting process is dried using a shelf dryer (a vacuum constant temperature dryer “DRV320DA” manufactured by ADVANTEC) so that the moisture content of the pulp after drying is 0.4% by mass. did. The crystallinity of the pulp after the drying treatment was 79%, and the molecular weight was 26,000.

[Low crystallization treatment]
100 g of the pulp obtained by the drying treatment is put into a batch-type vibration mill (Chuo Kako Co., Ltd., “MB-1”, total container capacity 3.5 L), and the rod has a diameter of 30 mm, a length of 218 mm, a material Thirteen stainless steel rods with a circular cross-sectional shape were filled into a vibration mill (filling rate 57%) and treated for 30 minutes under conditions of an amplitude of 8 mm and a circular rotation of 1200 cpm.
After completion of the treatment, no pulp sticking matter was found on the wall or bottom of the vibration mill. The obtained low crystalline cellulose had a molecular weight of 130,000 and a crystallinity of 5%. The results are shown in Table 1.

Comparative Example 1
In the drying process, except that the pulp obtained by the cutting process was dried so that the moisture content of the pulp after drying was 7.1% by mass, and the low crystallization process was performed for 1.75 hours. Cutting, drying and low crystallization were performed in the same manner as in Example 1. The crystallinity of the pulp after the drying treatment was 83%, and the molecular weight was 22 million. The molecular weight of the cellulose obtained after the low crystallization treatment was 116,000, and the crystallinity was 5%. The results are shown in Table 1.

Example 2
[Cutting]
As a cellulose-containing raw material, sheet-like wood pulp [“Boreregard” “Blue Bear Ultra Ether”, 800 mm × 600 mm × 1.5 mm, crystallinity 81%, cellulose content 96% by mass, water content 8.5% by mass %] Was shredded (Meiko Shokai Co., Ltd., “MSX2000-IVP440F”) and cut into a size of about 10 mm × 5 mm × 1.5 mm. The pulp obtained after the cutting treatment had a bulk density of 180 kg / m ³ .

[Crushing treatment]
The obtained chip-like pulp was charged into a twin-screw extruder (manufactured by Suehiro EPM, “EA-20”) at 2 kg / hr, and the shear rate was 660 sec ⁻¹ , the screw rotation speed was 300 rpm, and cooling water was allowed to flow from the outside. 1 pass processing. The twin-screw extruder is a fully meshing type co-rotating twin-screw extruder, and the screws arranged in two rows are combined with a screw portion having a screw diameter of 40 mm and 12 blocks alternately (90 °). The two screws have the same configuration. The temperature of the twin screw extruder was 30 to 70 ° C. due to heat generated by the treatment.
The average particle size of the pulp obtained after the crushing treatment was 156 μm, and the bulk density was 330 kg / m ³ .

[Drying treatment]
The pulp obtained by the crushing treatment was dried using a shelf dryer (a vacuum constant temperature dryer “DRV320DA” manufactured by ADVANTEC) so that the moisture content of the pulp after drying was 0.5 mass%. The crystallinity of the pulp after the drying treatment was 71%, and the molecular weight was 193,000.

[Low crystallization treatment]
The pulp obtained by the drying process in the same manner as in Example 1 except that the number of rods filled in the vibration mill was changed to 11 and the filling rate was 48%, and the low crystallization process was performed for 40 minutes. A low crystallization treatment was performed.
After completion of the treatment, no pulp sticking matter was found on the wall or bottom of the vibration mill. The obtained low crystalline cellulose had a molecular weight of 1480,000 and a crystallinity of 5%. The results are shown in Table 1.

Comparative Example 2
In the drying process, except that the pulp obtained by the cutting process was dried so that the moisture content of the pulp after drying was 6.1% by mass, and the low crystallization process was performed for 1.7 hours. Cutting, coarse crushing, drying and low crystallization were performed in the same manner as in Example 2. The crystallinity calculated from the X-ray diffraction intensity of the pulp after the drying treatment was 74%, and the molecular weight was 215,000. The molecular weight of the cellulose obtained after the low crystallization treatment was 116,000, and the crystallinity was 5%. The results are shown in Table 1.

  From Table 1, the manufacturing method of the low crystalline cellulose of Examples 1 and 2 is a low crystalline cellulose in which the crystallinity of the cellulose is reduced while suppressing the decrease in the molecular weight of the cellulose as compared with Comparative Examples 1 and 2. Can be efficiently obtained in a short time, and it can be seen that the productivity is excellent.

  The method for producing a low crystalline cellulose of the present invention is excellent in productivity, and can efficiently obtain a low crystalline cellulose having a reduced cellulose I type crystallinity while suppressing a decrease in molecular weight. It is useful as a manufacturing method. The obtained low crystalline cellulose is particularly useful as a raw material for cellulose ethers, industrial raw materials such as cosmetics, foods, and biomass materials.

Claims (6)

The cellulose content in the remaining components excluding water from the cellulose-containing raw material is 20% by mass or more, the cellulose I type crystallinity of the cellulose represented by the following formula (1) exceeds 33%, and the molecular weight of cellulose is 10 A cellulose-containing raw material having a water content of 10,000 to 1,000,000 and a water content of 4.5% by mass or less is processed by a pulverizer, and the cellulose I-type crystallinity is set to 1/25 to 1/100 before and after the pulverization treatment. A method for producing low crystalline cellulose, which is reduced to a low level.
Cellulose type I crystallinity (%) = [(I _22.6 -I _18.5 ) / I _22.6 ] × 100 (1)
[I _22.6 is the diffraction intensity of the lattice plane (002 plane) (diffraction angle 2θ = 22.6 °) in X-ray diffraction, and I _18.5 is the diffraction intensity of the amorphous portion (diffraction angle 2θ = 18.5 °). Show   The method for producing low crystalline cellulose according to claim 1, wherein the pulverizer is a medium pulverizer.   The manufacturing method of the low crystalline cellulose of Claim 1 or 2 whose cellulose containing raw material is pulps or papers. The manufacturing method of the low crystalline cellulose in any one of Claims 1-3 whose bulk density of the said cellulose containing raw material is 50-500 kg / m < ³ >.   The low crystalline cellulose according to any one of claims 1 to 4, wherein the cellulose-containing raw material is obtained by a cutting process using one or more cutting machines selected from a shredder, a slitter cutter, and a rotary cutter. Manufacturing method.   The method for producing low crystalline cellulose according to any one of claims 1 to 5, wherein the cellulose-containing raw material has a water content reduced to 4.5% by mass or less by a drying treatment.