JP2022160303A - Powdery cellulose, use and production method thereof - Google Patents

Abstract

To provide a powdery cellulose that can ensure an appropriate physical property in a resin composition or the like, without performing modification such as derivatization of cellulose.SOLUTION: Provided is a powdery cellulose that has an average particle size of 5 to 150 μm, has an apparent specific gravity of 0.1 to 0.45 g/ml, and has a dispersibility in water (BS) of more than 5.0% and 20.0% or less. Provided, furthermore, are a powdery cellulose that is characterized by having an apparent specific gravity of 0.1 to 0.28 g/ml, and an industrial additive, a resin composition, a rubber composition and a molding that contain the same.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to powdered cellulose, its use and production method.

Powdered cellulose has characteristics such as thickening properties, emulsion stability, water retention, oil absorption, and shape retention. Therefore, powdered cellulose is used as food additives, tablet excipients, dispersants, shape retention agents, water retention agents, filter aids, fillers, additives for paints and adhesives, etc. , building materials, ceramics, rubber, plastics, etc. In particular, in recent years, due to the growing environmental awareness, it is expected to expand into the fields of rubber and plastics, and there is a demand for powdery cellulose suitable for such uses.

Cellulose is utilized in such resin compositions by altering the properties of cellulose in order to increase its affinity for resins.
For example, in Patent Document 1, in order to obtain good physical properties as a resin composition, a low-crystalline cellulose composite obtained by pulverizing a cellulose-containing raw material in the presence of a polymer having a cellulose affinity site is used. is disclosed.
Patent document 2 discloses a cellulose derivative obtained by esterifying cellulose and adding a chain structure thereto.

Japanese Patent Application Laid-Open No. 2018-104702 JP 2018-59125 A

However, such alteration of cellulose requires the use of a large amount of energy and chemical substances, and improvements have been desired for use in bioplastics, which is required to reduce the environmental load.
In addition, chemical substances used for denaturation of cellulose are mixed in the resin composition as trace components, which has been a concern when obtaining bioplastics with high purity.

Accordingly, an object of the present invention is to provide a powdery cellulose that can ensure appropriate physical properties for a resin composition or the like without undergoing alteration such as derivatization of cellulose.

The present invention provides the following [1] to [6].
[1] An average particle size of 5 to 150 μm, an apparent specific gravity of 0.1 to 0.45 g/ml, and a dispersibility in water (BS) of more than 5.0% and 20.0% or less powdered cellulose.
[2] The powdery cellulose according to [1], which has an apparent specific gravity of 0.1 to 0.28 g/ml.
[3] An industrial additive containing the powdered cellulose according to any one of [1] to [2].
[4] A resin composition containing the powdery cellulose according to any one of [1] to [2].
[5] A rubber composition containing the powdered cellulose according to any one of [1] to [2].
[6] A molded body containing the powdered cellulose according to any one of [1] to [2].

According to the present invention, it is possible to provide powdery cellulose that can ensure appropriate physical properties for a resin composition or the like without derivatization or other alteration of cellulose.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments. In this specification, the notation "AA to BB" indicates from AA to BB.

[Powder cellulose]
The powdery cellulose of the present invention preferably has the following physical properties, and usually has at least a predetermined average particle size and water dispersibility (BS) among the following physical properties.

<Dispersibility in water (BS)>
The water dispersibility (BS) of powdered cellulose is usually 5% or more, preferably 8.0% or more, more preferably 10.0% or more. The upper limit is usually 20.0% or less, preferably 19.0% or less, more preferably 17.0% or less. Since the dispersibility in water is within the above range, it is expected to exhibit good dispersibility when kneaded into a resin composition or the like, and is uniformly distributed in the resin composition, and when formed into a molded product. It is expected that good mechanical properties can be exhibited.

Dispersibility in water is presumed to affect the shape of powdered cellulose, and comprehensively represents physical properties of powdered cellulose (e.g., particle shape (e.g., spherical, rod-like, bent rod-like), degree of fibrillation). It can be said that it is an index. When the dispersibility in water is within the above range, the resin composition or the like containing such powdery cellulose has a specific shape of powdery cellulose localized like an aggregate in an appropriate distribution. It is expected that the desired physical properties are likely to be exhibited.

Dispersibility in water can be measured under the following conditions. 15 mL of a 0.5% by weight aqueous dispersion of powdered cellulose was stirred at 500 rpm for 30 seconds, and after quickly removing the stirrer, it was poured into a cylindrical glass cell with a diameter of 25 mm. A position of 16 mm is irradiated with incident light having a wavelength of 880 nm. The backscattered light from the measurement sample is detected at a position of 135° with respect to the incident light, and the backscattered light intensity (%) is measured 30 minutes after the start of measurement. The measurement starts within 1 minute from the preparation of the measurement sample.

<Particle size distribution, average particle size, span of particle size distribution>
The particle size distribution of the powdered cellulose is the particle size distribution when the integrated value of the volume accumulation distribution is 10%, 0%, and 90% (10% diameter, 50% diameter, 90% diameter, D.10, D.50, D.90). As used herein, the particle size distribution is a value obtained by wet measurement (with ultrasonic irradiation), wet measurement (without ultrasonic irradiation), or dry measurement using a laser scattering method as a measurement principle.

The span of the particle size distribution is a numerical value indicating the breadth of the particle size distribution. It is presumed to affect the shape of powdered cellulose, and in the present invention, it can be said to be an index that comprehensively represents the particle shape (spherical, rod-shaped, bent rod-shaped, etc.) of powdered cellulose and the state of fiber aggregation. Powdered cellulose with a particle size distribution span in an appropriate range has an appropriate fiber length and fiber width, and when kneaded into a resin composition or the like, the kneadability with the resin or the like increases. A strong structure can be constructed by properly dispersing the fibers therein, and the physical properties of the resin composition, etc., can be exhibited with a good balance.

The span of the particle size distribution is the D.O.M. obtained by each method. 10, D. 50, D. Calculated by substituting 90 into the following formula (3).
Formula (3): Span of particle size distribution = ((D.90) - (D.10)) / (D.50)

-Conditions for wet measurement (without ultrasonic irradiation)-
In the present specification, wet conditions (without ultrasonic irradiation) refer to conditions in which the particle size is measured as it is without ultrasonic irradiation after adding water to the sample. D.C. under wet conditions (no ultrasonic irradiation). 10, D. 50, D. 90, the preferred range of span is as follows. D. 10 is usually 5 μm or more, preferably 8.0 μm or more, more preferably 10.0 μm or more. The upper limit is usually 25.0 μm or less, preferably 20.0 μm or less, more preferably 15.0 μm or less.
D. 50 (average particle diameter) is usually 5.0 μm or more, 10.0 μm or more, 20.0 μm or more, preferably 30.0 μm or more, more preferably 35.0 μm or more (however, D.10 is larger than value). As a result, it is possible to suppress an increase in cohesiveness of powdered cellulose and a decrease in powder fluidity resulting therefrom, and to suppress deterioration of workability. The upper limit is usually 150.0 µm or less, preferably 100 µm or less, more preferably 80.0 µm or less, and even more preferably 65.0 µm or less. As a result, when kneaded with a resin composition or the like, it is possible to obtain good surface properties without surface roughness.
D. 90 is usually 100.0 µm or more, preferably 120.0 µm or more, more preferably 130 µm or more, and still more preferably 135.0 (however, it is a value larger than D.50). The upper limit is 250.0 μm or less, preferably 220 μm or less, more preferably 200 μm or less, and even more preferably 195 μm or less.
The span of the particle size distribution is usually 1.5 or more, preferably 2.0 or more, more preferably 2.2 or more, still more preferably 2.5 or more. The upper limit is usually 5.0 or less, preferably 4.5 or less, more preferably 4.0 or less.

－Wet measurement (with ultrasonic irradiation)－
In the present specification, wet conditions (with ultrasonic irradiation) refer to conditions in which the particle size is measured after adding water to the sample and then irradiating ultrasonic waves. D. in case of wet type (with ultrasonic wave) 10, D. 50, D. 90, the preferred range of span is as follows.
D. 10 is usually 1.0 μm or more, 3.0 μm or more, or 5.0 μm or more, preferably 7.0 μm or more, or 8.0 μm or more, more preferably 9.0 μm or more, and still more preferably 10.5 μm or more. The upper limit is usually 20.0 μm or less or 18.0 μm or less, preferably 15.0 μm or less, more preferably 13.0 μm or less.
D. 50 is usually 5 or more, 10.0 μm or more, or 15.0 μm or more, preferably 20.0 μm or more, more preferably 25.0 μm or more, and still more preferably 30.0 μm or more or 35.0 μm or more (where D .10). The upper limit is usually 70.0 μm or less, preferably 60.0 μm or less, more preferably 50.0 μm or less.
D. D.90 is usually 50.0 μm or more, preferably 80.0 μm or more, more preferably 100.0 μm or more, still more preferably 120.0 μm or more (however, it is a value larger than D.50). The upper limit is 300.0 μm or less, preferably 250.0 μm or less, more preferably 220.0 μm or less, still more preferably 200.0 μm or less.
The span of the particle size distribution is usually 2.0 or more, preferably 2.4 or more, more preferably 2.8 or more, and still more preferably 3.0 or more or 3.2 or more. The upper limit is usually 5.0 or less, preferably 4.5 or less, more preferably 4.0 or less.

－Dry measurement－
In the present specification, dry measurement refers to conditions for measuring the particle size as it is without adding water to the sample. D for dry measurements. 10, D. 50, D. 90, the preferred range of span is as follows.
D. 10 is usually 1.0 μm or more, 3.0 μm or more, preferably 5.0 μm or more, more preferably 7.0 μm or more, and still more preferably 10.0 μm or more. The upper limit is usually 30.0 μm or less, preferably 25 μm or less, more preferably 20.0 μm or less, still more preferably 18.0 μm or less.
D. D.50 is usually 5.0 μm or more, 10.0 μm or more, preferably 20.0 μm or more, more preferably 25.0 μm or more (however, it is a value larger than D.10). The upper limit is usually 100.0 µm or less, preferably 80.0 µm or less, more preferably 70.0 µm or less.
D. 90 is usually 90.0 µm or more, preferably 100.0 µm or more, more preferably 150.0 µm or more, and still more preferably 170.0 µm or more (however, it is a value larger than D.50). The upper limit is 300.0 μm or less, more preferably 280.0 μm or less.
The span of the particle size distribution is usually 1.5 or more, preferably 2.0 or more, more preferably 2.5 or more, still more preferably 3.0 or more. The upper limit is usually 9.0 or less, preferably 6.0 or less, more preferably 5.0 or less, still more preferably 4.5 or less.

By satisfying the above range, when kneaded into a resin composition or the like, the kneadability with the resin component or the like increases, and it can be dispersed uniformly in the composition. It is possible to satisfactorily exhibit the mechanical properties expected for such molded articles.

<Ratio of length/breadth (L/D)>
The length/breadth ratio (L/D) of powdered cellulose is usually 3.5 to 7.0, preferably 3.5 to 6.5, more preferably 4.0 to 6.0. be.

L/D is presumed to affect the shape of powdered cellulose, and can be said to be an index that comprehensively represents the particle shape (spherical, rod-shaped, bent rod-shaped, etc.) of powdered cellulose, the state of fiber aggregation, and the like. When the L/D is within the preferred range described above, it has an appropriate fiber length and fiber width, and when kneaded into a resin composition or the like, it tends to exhibit the expected effect as an aggregate.

L/D is a value calculated under the following conditions. Using an optical microscope, powdery cellulose is observed at a magnification of 100 times, L and D of 140 randomly selected powdery celluloses are measured, and L/D of each is calculated. Of the calculated L/D, the average value of 100 pieces of powdered cellulose in total excluding 20 values on the upper and lower sides is calculated. The length (L) refers to the maximum fiber width of powdered cellulose observed with an optical microscope. The short diameter (D) refers to the minimum value perpendicular to the long diameter of the powdery cellulose fiber width observed with an optical microscope. When the powdery cellulose has a folded structure, L is the maximum fiber width in the folded state. L is usually 35 or more, preferably 40 or more, more preferably 41 or more. The upper limit is usually 60 or less, preferably 55 or less, more preferably 53 or less. D is usually 6 or more, preferably 7 or more, more preferably 8 or more. The upper limit is not particularly limited as long as it is 15 or less. It is preferable that both L/D and L are within the above range, since disintegration properties are further improved. The L/D measurement is that the powdery cellulose has a powdery moisture content of 3.0 to 4.0% as measured with an infrared moisture meter (manufactured by Kett Science Laboratory, model FD-720, 1g, 105°C). Check before doing.

[Method for producing powdered cellulose]
The method for producing powdered cellulose is not particularly limited as long as it is a method for obtaining powdered cellulose from a cellulose raw material. In addition, an acid hydrolysis treatment can be performed to reduce the degree of polymerization of cellulose and to reduce impurities.

<Cellulose raw material>
The cellulose raw material is usually naturally derived cellulose, preferably pulp, more preferably wood-derived pulp. Wood-derived pulps include, for example, hardwood-derived pulps and softwood-derived pulps. Methods of preparing wood-derived pulp include, for example, methods involving treatment by pulping (cooking). The pulping method (cooking method) dissolves and removes the lignin, which is a coloring substance, so that pulp with a high degree of whiteness can be obtained. Pulping methods (cooking methods) include, for example, sulfite cooking method, kraft cooking method, soda/quinone cooking method, and organosolv cooking method, and kraft pulp is preferred from an environmental point of view.

In the pulp preparation method, it is preferable to perform a bleaching treatment in addition to the pulping method (cooking method). This results in a pulp with a higher degree of whiteness. Bleaching methods include, for example, chlorination (C), chlorine dioxide bleaching (D), alkali extraction (E), hypochlorite bleaching (H), optionally on conventional delignified pulp. Hydrogen peroxide bleaching (P), alkaline hydrogen peroxide treatment stage (Ep), alkaline hydrogen peroxide and oxygen treatment stage (Eop), ozonation (Z), chelate treatment (Q), and two or more of these treatments A method of applying a combination may be mentioned. As a combination (sequence) of two or more processes, for example, DE
/P-D, C/D-E-H-D, ZE-D-PZ/D-Ep-D, Z/D-Ep-DP, D-Ep-D, D-Ep-D -P, D-Ep-P-D, Z-Eop-D-D, Z/D-Eop-D, Z/D-Eop-D-E-D ("/" in the sequence is "/" (meaning that the treatments before and after the treatment are continuously performed without washing). The bleaching treatment is not limited to the above examples, and may be a commonly used method. Pulp that has undergone bleaching treatment is usually in a fluid state (fluid pulp). The brightness of the pulp is preferably 80% or more based on ISO 2470.

<Acid hydrolysis treatment>
When acid hydrolysis treatment is performed, examples of the acid include mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid. The acid concentration is not particularly limited, but from the viewpoint of maintaining the degree of polymerization and whiteness, it is preferably lower than the acid concentration in the conventional acid hydrolysis treatment for producing powdered cellulose, and 0.4 to 2.0 N is preferable. More preferably 0.5 to 1.5N. The reaction conditions for the acid hydrolysis treatment are not particularly limited, but the reaction temperature is usually 80 to 100° C., and the reaction time is usually 30 minutes to 3 hours.

Prior to the acid hydrolysis treatment, the cellulose raw material may be pretreated. For example, slurrying of the cellulose raw material (preparation of a dispersion) and adjustment of the concentration of the cellulose raw material can be mentioned. The concentration of the cellulose raw material is usually 3 to 10% by weight (converted to solid content) relative to the dispersion. When the cellulose raw material is fluid pulp that has undergone a bleaching treatment, it is usually treated to increase the pulp consistency before hydrolysis. A dehydrator such as a screw press or a belt filter may be used to adjust (concentrate) the concentration of the cellulose raw material. The acid hydrolysis treatment may be performed on the slurry of the cellulose raw material, but may also be performed on the sheet-like cellulose raw material. When the cellulose raw material is a dry sheet of pulp, the pulp is usually loosened before acid hydrolysis treatment. When loosening the pulp, a crusher such as a roll crusher may be used.

<Neutralization/washing/deliquoring/drying treatment>
After the hydrolysis treatment, the obtained treated product undergoes pretreatment as appropriate before the pulverization treatment. Examples of the pretreatment include neutralization, washing, deliquoring, and drying, and it is preferable to perform neutralization, washing, deliquoring, and drying in this order. The neutralization treatment may be performed by adding an alkaline agent. The deliquoring process is usually a solid-liquid separation process, and waste acid can be separated from the hydrolyzed product. Additionally, the hydrolyzate may undergo a drying (dehydration) treatment. Thereby, the solid content concentration can be adjusted, and the physical property values of the powdered cellulose can be easily controlled. The solid content concentration is usually adjusted to 15% or more, preferably 20% or more.

<Pulverization processing>
In order to obtain the powdery cellulose of the present invention, the pulverization treatment may be performed by directly mechanically pulverizing the raw material pulp, or by mechanically pulverizing the processed product that has undergone acid hydrolysis or the like. good too. The powdery cellulose of the present invention needs to be kept coarse to some extent in order to achieve an appropriate average particle size, residual rate of ultrasonic waves in water, and apparent specific gravity. Adjustment is easier without it. At the same time as pulverization or after pulverization, classification treatment may be performed.

Examples of pulverizers include the following.
Cutting type mill: Mesh mill (manufactured by Horai Co., Ltd.), Atoms (manufactured by Yamamoto Hyakuma Seisakusho Co., Ltd.), knife mill (manufactured by Palman), cutter mill (manufactured by Tokyo Atomizer Manufacturing Co., Ltd.), CS cutter (manufactured by Mitsui Mining Co., Ltd.) ), rotary cutter mill (manufactured by Nara Machinery Co., Ltd.), turbo cutter (manufactured by Freund Corporation), pulp crusher (manufactured by Zuiko Co., Ltd.), and shredder (manufactured by Shinko Pantec Co., Ltd.).
Hammer type mill: Jaw crusher (manufactured by Makino Co., Ltd.), Hammer crusher (manufactured by Makino Sangyo Co., Ltd.), and Micro Pulperizer (manufactured by Hosokawa Micron Corporation).
Impact mill: Pulverizer (manufactured by Hosokawa Micron Corporation), Fine Impact Mill (manufactured by Hosokawa Micron Corporation), Super Micron Mill (manufactured by Hosokawa Micron Corporation), Inomizer (manufactured by Hosokawa Micron Corporation), Fine Mill (manufactured by Nippon Pneumatic Industry Co., Ltd.) ), CUM type centrifugal mill (manufactured by Mitsui Mining Co., Ltd.), Exceed mill (manufactured by Makino Sangyo Co., Ltd.), Ultraplex (manufactured by Makino Sangyo Co., Ltd.), Contraplex (manufactured by Makino Sangyo Co., Ltd.), Coroplex (Makino Sangyo Co., Ltd.) company), sample mill (manufactured by Seishi Co., Ltd.), bantam mill (manufactured by Seishin Co., Ltd.), atomizer (manufactured by Seishin Co., Ltd.), tornado mill (manufactured by Nikkiso Co., Ltd.), Nea Mill (manufactured by Dalton Co., Ltd.), HT type fine grinding Machine (manufactured by Horai Co., Ltd.), Jiyu Pulverizer (manufactured by Nara Machinery Co., Ltd.), New Cosmomizer (manufactured by Nara Machinery Co., Ltd.), Turbo Mill (manufactured by Freund Co., Ltd.), Gather Mill (manufactured by Nishimura Machinery Co., Ltd.) ), spar powder mill (manufactured by Nishimura Machinery Co., Ltd.), blade mill (manufactured by Nisshin Engineering Co., Ltd.), super rotor (manufactured by Nisshin Engineering Co., Ltd.), Npa crusher (manufactured by Sansho Industry Co., Ltd.), Wiley crusher (manufactured by Sanki Seisakusho Co., Ltd.), pulp grinder (manufactured by Zuiko Co., Ltd.), Jacobson fine pulverizer (manufactured by Shinko Pantech Co., Ltd.), and universal mill (manufactured by Tokuju Kosakusho Co., Ltd.).
Air flow mill: CGS type jet mill (manufactured by Mitsui Mining Co., Ltd.), micron jet (manufactured by Hosokawa Micron Co., Ltd.), counter jet mill (manufactured by Hosokawa Micron Co., Ltd.), cross jet mill (manufactured by Kurimoto, Ltd.), supersonic speed Jet Mill (manufactured by Nippon Pneumatic Industry Co., Ltd.), Current Jet (manufactured by Nisshin Engineering Co., Ltd.), Jet Mill (manufactured by Sansho Industry Co., Ltd.), Ebara Jet Micronizer (manufactured by Ebara Corporation), Ebara Triad Jet (manufactured by Ebara Corporation), Selenmirror (manufactured by Masuko Sangyo Co., Ltd.), New Microcactmat (manufactured by Masuno Seisakusho Co., Ltd.), and Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.).
Vertical roller mill: vertical roller mill (manufactured by Chinion Co., Ltd.), vertical roller mill (manufactured by Schaeffler Japan Co., Ltd.), roller mill (manufactured by Kotobuki Giken Kogyo Co., Ltd.), VX mill (Kurimoto, Ltd.), KVM type vertical mill (Earth Technica Co., Ltd.) and IS mill (IHI Plant Engineering Co., Ltd.).
Among these, a vertical roller mill and a mesh mill are preferable because they are excellent in pulverization property while maintaining desired physical properties.

The conditions for the pulverization treatment or the classification treatment performed as necessary can be appropriately set so as to obtain the desired powdery cellulose. For example, the processing conditions can be adjusted with reference to a calibration curve created from the pulverization conditions (eg, processing time, input amount) and the desired physical properties of the powdered cellulose.

During the pulverization treatment, if necessary, at least one other component (for example, an organic component or an inorganic component) may be subjected to the pulverization treatment together with the raw material pulp or the acid-hydrolyzed product. It has been found that it is desirable to keep (or not add) other ingredients as small as possible.

If necessary, the powdery cellulose may be chemically treated. do not have.

[Uses of powdered cellulose]
Powdered cellulose can be used as an industrial additive for resin compositions, rubber compositions and the like. Thereby, the molded articles obtained therefrom can exhibit good mechanical properties.

Although the present invention will be specifically illustrated by the following examples, the present application is of course not limited to such examples. The test methods in the examples of the present application are shown below. Unless otherwise specified, the method for measuring physical properties is the method described above.

<Dispersibility in water (BS)>
Powdered cellulose was adjusted to a concentration of 0.5% by weight with pure water, and stirred at 500 rpm for 30 seconds to prepare a measurement sample. After quickly removing the stirrer, 15 mL of the prepared measurement sample was poured into a cylindrical glass cell with a diameter of 25 mm, and incident light with a wavelength of 880 nm was placed at a height of 16 mm from the bottom of the measurement sample in the cell. irradiated. The backscattered light intensity (%) was measured by detecting the backscattered light from the measurement sample at a position of 135° with respect to the incident light. The measurement started within 1 minute from the preparation of the measurement sample. As a device for measuring the backscattered light intensity of the measurement sample, "Turbiscan Lab" manufactured by Eko Seiki Co., Ltd. was used.

<Particle size distribution, average particle size, span of particle size distribution>
A laser diffraction particle size distribution analyzer (Mastersizer 3000, Spectris Malvern Panalytical Division) was used. The particle size distribution was measured by dry measurement, wet measurement (with ultrasonic irradiation), and wet measurement (without ultrasonic irradiation) using a laser scattering method as the measurement principle. When the particle size distribution is expressed as a volume accumulation distribution, the values at which the integrated value of the volume accumulation distribution is 10%, 50%, and 90% are defined as the particle size distribution D. 10, D. 50, D. 90. Wet (without ultrasonic irradiation) D.I. 50 was taken as the average particle size. Also, the span of the particle size distribution was calculated by the above formula (1).

The dry measurement was performed under the following conditions by adding the sample into the supply port so that the scattering intensity was less than 1%.
・Dispersion unit: Aero5
・Air pressure: 2bar
・Feed rate: 25

The wet measurement was carried out by adding the sample to a measurement part in water stirred at 3500 rpm so that the scattering intensity was about 10%. In the case of irradiating ultrasonic waves, the wet measurement was performed after applying ultrasonic waves to the sample in water under the following conditions.
・Mode: Continuous ・Intensity: 100%
・Time: 600 seconds

The analysis of the particle size distribution was performed under the following conditions for any measurement conditions.
・Analysis: General purpose ・Analysis sensitivity: Emphasis ・Light scattering model: Mie theory

<Preparation of powdered cellulose>
<Example 1>
The chlorine-free bleached pulp is mechanically pulverized and classified as appropriate using a mesh mill (HA8-2542-25E, manufactured by Horai Co., Ltd.), and powdered with an average particle size of 46.5 μm and an apparent specific gravity of 0.22 g / ml. A cellulose was obtained.

<Example 2>
The chlorine-free bleached pulp is mechanically pulverized and classified as appropriate using a mesh mill (HA8-2542-25E type, manufactured by Horai Co., Ltd.), and is powdered with an average particle size of 39.3 μm and an apparent specific gravity of 0.24 g / ml. A cellulose was obtained.

<Example 3>
The chlorine-free bleached pulp was appropriately pulverized and classified mechanically using a vertical roller mill (manufactured by Seishin Co., Ltd.) to obtain powdered cellulose having an average particle size of 35.6 μm and an apparent specific gravity of 0.4 g/ml.

Table 1 shows physical properties and measured values of each sample.

Claims (6)

Powdery cellulose having an average particle size of 5 to 150 μm, an apparent specific gravity of 0.1 to 0.45 g/ml, and a dispersibility in water (BS) of more than 5.0% and not more than 20.0%. . Powdered cellulose according to claim 1, characterized in that it has an apparent specific gravity of 0.1-0.28 g/ml. An industrial additive comprising the powdered cellulose according to any one of claims 1-2. A resin composition comprising the powdery cellulose according to any one of claims 1 and 2. A rubber composition comprising the powdered cellulose according to any one of claims 1 and 2. A molded body containing the powdered cellulose according to any one of claims 1 and 2.