JPS61241337A - Fine cellulose particle and production thereof - Google Patents

Abstract

PURPOSE:Fine cellulose particles, obtained by incorporating viscose with a water-sluble anionic high polymer to form a fine particulate dispersion of the viscose and coagulating and neutralizing the resultant dispersion, consisting of cellulose II and having a sharp particle size distribution. CONSTITUTION:One pts.wt. viscose is incorporated with 0.03-100pts.wt. water- soluble anionic high polymer, e.g. having sulfonic acid groups, phosphonic acid groups, etc., to form a fine particulate dispersion of the viscose, which is then heated or mixed with a coagulating agent to coagulates the viscose. The coagulated viscose is then neutralized with an acid or the dispersion is coagulated with the acid and neutralized to from fine particles of the viscose, which are then separated from the mother liquor, and as necessary, desulfurized, washed with an acid and then water and dried to give the aimed fine cellulose particles, which are spherical or spheroidal particles, consisting of cellulose II, having 5-30% crystallinity, <=20mum average particle diameter, and containing >=70wt%, based on the total particles, particles having within + or -5mum particle diameter range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to microcellulose particles and a method for producing the same. More specifically, the present invention relates to minute cellulose particles that are substantially free from recycled cellulose and have a sharp particle size distribution, and a method for producing the same.

(Prior Art) Particles of cellulose or its various derivatives have recently come to be widely used in various fields as chromatography materials, polymer carriers, cosmetic additives, lubricants, and the like.

Conventionally, high-purity microcrystalline cellulose developed by FMC Corporation of the United States is well known as microcellulose particles. This high-purity microcrystalline cellulose is produced by selecting particularly high-purity refined pulp, hydrolyzing it with mineral acid under certain conditions to wash and remove amorphous regions, and then grinding, purifying, and drying it. (Asahi Kasei Kogyo Co., Ltd., March 1, 1988, "Crystalline cellulose,
(See the pamphlet titled “Abysse D”). According to the same pamphlet, the high-purity microcrystalline cellulose is chemically natural cellulose, that is, IW cellulose itself, and for example, the average particle size ranges from as small as about 6 μm to about 40 μm or 120 μm. It can be seen that even large ones are commercially available. According to the research of the present invention, this high-purity microcrystalline cellulose (grade PH-MO6) has been found to have relatively good crystallinity with a degree of crystallinity of about 31 to 35%.

JP-A-48-21738 discloses that the heptavalent is 50 or more,
A method is disclosed in which viscose having an average degree of polymerization of 400 or more is dropped in the form of particles into a coagulation regeneration bath having a low acid concentration and a low mirabilite concentration to gradually perform coagulation and regeneration. The examples in the same publication include 30 to 46 meshes (300 to 590 μm).
m) regenerated cellulose granules are described.

Japanese Patent Publication No. 56-21,761 describes a method in which viscose is pushed through a discharge port, naturally changes from a continuous flow to a droplet flow in the air, and is supplied to a coagulation/regeneration bath as nearly spherical droplets. is disclosed. According to the same method, #)16
It is described that cellulose granules of ~170 mesh (88-1168 μm) are obtained.

Japanese Patent Publication No. 57-7162 discloses hollow regenerated cellulose fine particles having a large void in the center. The granules are described to have an apparent density of less than 0.49 cm" and a mesh size of 16 to 170 mesh.

Japanese Unexamined Patent Publication No. 48-60753 includes the aforementioned Unexamined Japanese Patent Application No. 48-60753.
i5.1 by using a coagulation regeneration bath with a higher acid concentration and mirabilite concentration than the method disclosed in Japanese Patent No. 21738.
A method for producing porous regenerated cellulose particles of 6 to 170 mesh is disclosed.

Japanese Patent Publication No. 49-89,748 discloses that fibrous materials of recycled cellulose are hydrolyzed, dried, and pulverized, and the length/diameter ratio is 20/1 to 2/l. Disclosed is a method for producing cellulose powder having a cellulose powder of lll11 or less.

JP-A-57-214231 discloses a method for producing cellulose powder from fibrous natural cellulose in the same manner as above.

Japanese Patent Publication No. 57-45,254 discloses that a viscose suspension in a water-immiscible liquid such as chlorobenzene is heated to a temperature of 30 to 100° C. with continuous stirring to solidify it,
Next, by acid decomposing the generated particles, the particle size is reduced to 150.
It is disclosed that particles (Example 1) are obtained in which particles of ~350 μm occupy 85 volumes.

Japanese Patent Publication No. 55-39565 discloses that a solution of cellulose triacetate in methylene chloride or chloroform is dropped into an aqueous medium in which a dispersant such as gelatin or polyvinyl alcohol is dissolved, while stirring, and then heated to dissolve triacetic acid. A method for producing cellulose spherical particles by forming cellulose spherical particles and then saponifying the same is disclosed. Examples of the publication disclose cellulose particles of 30 to 500 μm.

Japanese Patent Publication No. 55-40618 discloses a method for producing cellulose particles of 50 to 500 μm from cellulose esters other than cellulose triacetate in exactly the same manner as described above.

JP-A No. 55-28,763 states that the boiling point difference is 30°C.
A method for producing microspherical particles by spray-drying a solution of cellulose fatty acid ester dissolved in a mixed solvent of three or more different solvents is disclosed.

JP-A-57-159,801 discloses that cellulose is dissolved in a DM80 solution of paraformaldehyde, the resulting solution is dispersed in a liquid, and mixed with a coagulant for cellulose to form dispersed droplets of cellulose. A method is disclosed for producing granular cellulose gel by gelation agglomeration and optional regeneration with hot water.

JP-A-57-159802 discloses a method for producing porous cellulose by immersing granular cellulose in a DMSO solution of paraformaldehyde, and heating and swelling the cellulose.

JP-A-57-219,333 discloses that an aqueous medium solution containing an organic solvent solution of cellulose acetate, a dispersant, a surfactant, and an antifoaming agent is heated at a circumferential speed of a rotor blade of 450 m/min or more, 2000 rpm or more, and A method is disclosed for producing spherical microparticles of cellulose acetate by stirring and mixing for at least 10 seconds and evaporating the organic solvent.

JP-A-48-30,752 discloses a method for producing cellulose powder by treating cellulose with tetrahydrofuran and then pulverizing it.

JP-A-50-105,758 discloses that a dried cellulose sheet is passed between a pair of rotating rolls under pressure,
A method for producing fine cellulose powder by subsequent hydrolysis with a mineral acid is disclosed.

[Problem that the invention seeks to solve]

It is an object of the present invention to provide microcellulose particles consisting essentially of regenerated or old cellulose and having a sharp particle size distribution.

Another object of the present invention is to use old cellulose which has a sharp particle size distribution in which particles having a small average particle size of 20 μm or less and in the range of ±5 μm account for more than 70% of the total weight of the particles. The purpose is to provide microparticles.

Still another object of the present invention is to provide a novel method for producing the microcellulose particles of the present invention as described above.

Still another object of the present invention is to provide the above-mentioned novel manufacturing method, which includes the step of mixing viscose and a water-soluble anionic polymer compound to produce a viscose dispersion.

Still another object of the present invention is to have a sharp particle size distribution;
The object of the present invention is to provide fine particles of old cellulose that can be used in various fields by itself or in combination with other particles having different particle size distributions.

Further objects and advantages of the invention will become apparent from the description below.

[Means and effects for solving the problems] According to the present invention, the above-mentioned objects and advantages of the present invention are achieved by: (a) consisting essentially of type II cellulose;
The degree of crystallinity determined by X-ray diffraction is in the range of 5 to 30%, (C) the particle size consists essentially of spherical or oblate particles with an average particle size of 20 μm or less, and (d) the particle size is in the range of 5 to 30%. This is achieved by using micro cellulose particles characterized in that they have a particle size distribution in which particles in the particle size range of average particle diameter (μm) ±5 μm account for 70% or more of the total weight of the particles.

According to the present invention, the micro cellulose particles of the present invention are produced by: (1) mixing viscose and a water-soluble anionic polymer compound to produce a fine particle dispersion of viscose; (ii) coagulating the viscose in the dispersion by heating the dispersion or mixing the dispersion with a coagulant and then neutralizing with an acid to produce fine particles of cellulose; The liquid is coagulated and neutralized with acid to produce cellulose fine particles, and then (3) the cellulose fine particles are separated from the mother liquor and optionally desulfurized, pickled, washed with water, or dried. be able to.

According to the method of the present invention, a viscose fine particle dispersion is produced in the first step, cellulose fine particles are produced in the second step, and the cellulose fine particles are separated from the mother liquor in the third step.

The first step of producing a fine particle dispersion of viscose is carried out by mixing viscose and a water-soluble anionic polymer compound.

The viscose used has, for example, the following properties.

The gamma value is 30-100, more preferably 35-90. The salt point is between 3 and 20, more preferably between 4 and 18. Cellulose concentration is 3-15% by weight, more preferably 5%
~13% by weight. Alkali concentration is 2-15% by weight,
More preferably, it is 4 to 13% by weight. The weight ratio of alkali (as caustic soda) to cellulose in viscose is 40 to 100% by weight, more preferably 50 to 90% by weight.
Weight%. The viscosity of viscose is 5 at 20°C.
0 to 20,000 centipoise, more preferably 80 to
ia, ooo centipoise.

The pulp source for the viscose is preferably linter pulp, and may also be softwood or hardwood. The average 1' content of viscose as cellulose is usually 110 to 1.000.

The water-soluble anionic polymer compound used has, for example, a sulfonic acid group, a posponic acid group, or a carboxylic acid group as an anionic group. These anionic groups may be in the form of free acids or salts.

The water-soluble polymer compound having a sulfonic acid group as an anionic group may be a sulfonic acid group such as vinyl sulfonic acid, styrene sulfonic acid, methylstyrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, acrylamide metal propane sulfonic acid, or It can be derived from monomers such as these salts.

Similarly, water-soluble polymer compounds having a phosphonic acid group as a monoanionic group can be derived from monomers such as styrene bosponic acid, vinylphosphonic acid, or salts thereof.

Further, the water-soluble polymer compound having a carboxylic acid group as an anionic group can be derived from a monomer such as acrylic acid, methacrylic acid, styrene carboxylic acid, maleic acid, itamonic acid, or a salt thereof.

For example, a water-soluble polymer compound having a carboxylic acid group can be produced by polymerizing sodium acrylate alone or by mixing it with other copolymerizable monomers such as methyl acrylate according to a method known per se. Supplied as a homopolymer or copolymer containing polymerized units of acid soda. Furthermore, for example, a water-soluble polymer compound having a sulfonic acid group can be produced by sulfonating a styrene homopolymer.

The same applies to the case where the sulfonic acid group is derived from a monomer other than styrene sulfonic acid, and the case where the phosphonic acid group and the carboxylic acid group are respectively derived from the above monomers.

The water-soluble anionic polymer compound preferably has at least two polymerized units of the above-mentioned monomers having an anionic group.
Contains 0 molt. Such preferred polymer compounds include:
Copolymers and homopolymers are included.

The water-soluble anionic polymer compound preferably has a number average molecular weight of at least 5,000, more preferably 10,000 to 3,000,000.

The water-soluble anionic polymer compound in the present invention includes:
In addition to the vinyl type polymers mentioned above, other examples include carboxymethyl cellulose, sulfoethyl cellulose, and salts thereof such as Na salts.

According to the method of the present invention, viscose and a water-soluble anionic polymer compound are first mixed. For mixing, any means can be used as long as a fine particle dispersion of viscose is produced. For example, mechanical stirring using stirring blades, baffles, etc., ultrasonic stirring, or mixing using a static mixer can be carried out alone or in combination.

The water-soluble anionic polymer compound is preferably used as an aqueous solution, more preferably at a concentration of 0.5.
It is used as an aqueous solution of ~25% by weight, particularly preferably 2-22% by weight. Such an aqueous solution further has a viscosity of 3 centipoise to 50,000 centipoise at 20°C, particularly 5 centipoise.
It is preferable to have a centipoise to 30,000 centipoise.

The viscose and water-soluble anionic polymer compound are 0.3 to 100 parts by weight, more preferably 1 to 45 parts by weight, particularly preferably 4 to 20 parts by weight per 1 part by weight of cellulose. used and mixed. Advantageously, the mixing is carried out at a temperature lower than the boiling point of the carbon disulfide contained in the viscose, more preferably between 0 and 4
It is carried out in the range of 0°C.

By the first step of the method of the present invention, viscose can be finely divided into substantially spherical fine particles having an average particle size of 30 μm or less.

According to the method of the present invention, the viscose fine particle dispersion produced in the first step is then coagulated and neutralized in the second step to produce cellulose fine particles. Coagulation and neutralization may be performed simultaneously or sequentially.

If coagulation and neutralization are carried out over time, coagulation can be carried out by heating the dispersion or mixing the dispersion with a coagulant, and then neutralization is carried out by contacting with an acid. .

The coagulation reaction described above is desirably carried out while adding a mixing operation to the produced dispersion.

Coagulation by heating can be advantageously carried out at a temperature higher than the boiling point of carbon disulfide contained in the viscose, for example at a temperature of 50° to 90°C. In the case of coagulation using a coagulant, it is not necessary to raise the temperature to such a temperature, and coagulation can usually be carried out at a temperature of 0 to 40°C.

As the coagulant, for example, lower aliphatic alcohols, alkali metal salts or alkaline earth metal salts of inorganic acids, inorganic acids, organic acids, or combinations thereof, and combinations thereof with water-soluble polymer compounds are preferably used. The lower aliphatic alcohol may be linear or branched,
For example, aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol, 1so-7' lovanol, n-7' lovanol, and n-butanol are preferably used. Examples of inorganic acids include hydrochloric acid, sulfuric acid, phosphoric acid, and carbonic acid. Examples of alkali metal salts of inorganic acids include NaCl, Na, and So.

Salts such as Na salt, K, So, etc. are preferable, and alkaline earth metal salts include Mg804, etc.
Ca salts such as g-salt, CaC1, are preferred.

The organic acid is preferably a carboxylic acid or a sulfonic acid,
Examples include formic acid, acetic acid, propionic acid, benzoic acid, benzenesulfonic acid, toluenesulfonic acid, maleic anhydride, malic acid, and oxalic acid.

The coagulant as described above is used in a proportion of, for example, about 20 to 300% by weight based on the cellulose in the viscose.

As the acid used as the neutralizing agent, strong inorganic acids such as sulfuric acid and hydrochloric acid are preferably used.

The neutralizing agent is used in an amount sufficient to neutralize the viscose;
Generates fine particles of cellulose. Furthermore, the coagulation and neutralization in the second step described above can also be carried out simultaneously. Agents effective for coagulation and neutralization are acids, preferably strong inorganic acids such as hydrochloric acid or sulfuric acid. An acid used in an amount sufficient to neutralize viscose will be an amount sufficient to coagulate and neutralize the viscose.

Simultaneous coagulation and neutralization are advantageously carried out at temperatures of, for example, 0 to 40°C.

According to the method of the present invention, the cellulose fine particles produced in the second step are then separated from the mother liquor in the third step, and are desulfurized, pickled, washed with water, or dried if necessary. In some cases, bleaching may be performed after pickling. Separation of fine particles from the mother liquor can be performed, for example, by filtration, centrifugation, or the like. For desulfurization, for example, caustic soda,
This can be done with an aqueous alkali solution such as sodium sulfide.

If necessary, to remove residual alkali, the product is then pickled with dilute hydrochloric acid, washed with water, and dried.

Thus, according to the invention, as described above, (a)
(b) Crystallinity determined by X-ray diffraction method is in the range of 5 to 30%; (C) Spherical or long spheroidal particles with an average particle size of 20 μm or less and (d) has a particle size distribution in which particles having a particle size in the average particle size (μm) ± 5 μm account for 70% by weight or more of all particles. Inventive microcellulose particles are provided.

The microcellulose particles of the present invention are characterized by meeting the requirements (a) to (d) above. Each of these requirements will be explained below.

The microcellulose particles of the present invention consist essentially of type 1 KII cellulose, that is, regenerated cellulose.

Therefore, cellulose microparticles made of natural cellulose, i.e. type I cellulose, are completely different from the microparticles of the present invention. ■Type cellulose and ■type cellulose can be distinguished by the well-known method of X-ray diffraction.

In the X-ray diffraction diagram of type I cellulose, there is substantially no diffraction peak at a diffraction angle (2θ) of 15°, which clearly exists in type I cellulose.

Further, the micro cellulose particles of the present invention are secondly characterized by a degree of crystallinity determined by an X-ray diffraction method, and have a degree of crystallinity of 5 to 30. The micro cellulose particles of the present invention are preferably 10 to 28%, more preferably 15 to 26%
% crystallinity. The microcellulose of the present invention is not amorphous, but crystalline as specified by the above-mentioned crystallinity.

Thirdly, the micro cellulose particles of the present invention have an average particle size of 2
It consists essentially of spherical or long spherical particles of 0 μm or less. The micro cellulose particles of the present invention are thus composed of extremely micro particles.

The micro cellulose particles of the present invention further have an average particle size of 1
The particles are substantially composed of spherical or oblong spheroidal particles of 1.5 to 15 .mu.m, preferably 1.5 to 15 .mu.m. As used herein, the term "long spherical shape" is a concept that includes particles whose projected view or plan view has a shape such as an ellipse, an elongated circle, a peanut shape, or an egg shape. The microlamellar cellulose particles are spherical or elongated as described above, and are therefore different from particles that are rounded or irregularly shaped.The elongated microcellulose particles of the present invention are produced according to the method of the present invention described above. When moving from dispersion in the first step to coagulation in the second step, the viscose and water-soluble anionic polymer compound are mixed vigorously and coagulated to facilitate formation.

Fourthly, the micro cellulose particles of the present invention are particles of this type, such that particles whose particle size is located in a narrow range of 5 μm around the average particle size occupy 70% by weight or more of the total particle size. It has a very sharp particle size distribution. For example, when the average particle size of all particles is 10 μm, particles having a particle size in the range of 5 to 15 μm account for 70% by weight or more of all particles. By the way, it should be understood that the lower limit of the ±5 μm span is greater than zero and 8 μm or less when the average particle size is 3 μm, for example, since the lower limit will not be less than zero.

The micro cellulose particles of the present invention have an average particle size (μm
) The particles in the particle size range of ±5 μm are more than 75% of the total particle weight for those with a sharper distribution, and 80% for those with a sharper distribution.
The particle size distribution is 85% by weight or more for sharp particles, and 90% by weight for particularly sharp particles.

As physical property values characterizing the micro cellulose particles of the present invention, the following can be further mentioned.

The cellulose constituting the micro cellulose particles of the present invention is
Many of them usually exhibit a degree of polymerization in the range of 100 to 700, and many have a copper value of 3 or less, which is measured and defined by the method described below. Furthermore, many of the micro cellulose particles of the present invention have a degree of water swelling measured and defined by the method described below in the range of 100 to 500%, and a pore diameter of 0.01 to 500% as measured by the mercury porosimeter method. The volume of the 0.5 .mu.m pores is less than 60.times.10.sup.cm/g, so there is no possibility of a large number of micropores.

Based on the above, the micro cellulose particles of the present invention are fine and have a sharp particle size distribution, and since they are made of cellulose, they are relatively stable against chemicals and are not toxic, so they can be used, for example, in various pharmaceutical products. It can be used in a wide range of industrial fields as a diluent, cosmetic filler, food additive, etc.

The micro cellulose particles of the present invention are as described above (a) to (
It goes without saying that it can be used as an aggregate of fine particles having the characteristics of d), but if necessary, different aggregates of the microcellulose particles of the present invention having different average particle sizes and/or particle size distributions may be used. They can also be prepared and used by appropriately mixing them.

The present invention will be explained in detail with reference to Examples below.

Before that, methods for measuring various characteristic values in this specification will be described first.

Measuring method of crystallinity> Determine by X-ray diffraction method. In other words, 2θ is from 5° to 4
The X-ray diffraction curve up to 5° is calculated using the following equation.

Crystallinity (4) = -X 100 T/ where "-((a+c)-b)XKK=0.896
(Incoherent scattering correction coefficient of cellulose) a: Diffraction curve of non-quality starch (2θ = 5 to 45°)
area, b = area of air scattering curve (2θ = 5 to 45°), C: area of sample diffraction curve (2θ = 5 to 45°), Particle size distribution measurement method〉 About 0.117 samples were collected. The mixture was poured into 25 m of pure water to be stirred and dispersed, and measured using a light transmission particle size distribution analyzer 5KC-2000 manufactured by Seishin Co., Ltd. The weight frequency distribution is divided into 20 equal parts based on the maximum particle diameter, and the vertical axis represents the particle diameter and the horizontal axis represents the weight percentage (computer processing).

Method for Measuring Pore Volume of Microcellulose Particles Mercury Porosimeter Model 5-7121 manufactured by American Instrument Company rDIGITALREADOUT POR
Measured with O8IMETERJ.

The pore diameter was calculated using the following formula.

P where D = pore diameter (μm), P: pressure (Psia), pore volume at this pore diameter is the density of mercury 13.5585
Calculated using g/work 3 (15°C).

Here, V: Pore volume (Cm/l, Q: Mercury penetration amount (CC), S: Sample amount (g), <Water swelling degree> Micro cellulose particle amount 1, og is pure water with an amount of 20 times or more of the particle amount After soaking in water, the cellulose particle mixture was naturally filtered through a glass filter in which a cellulose acetate membrane having a hole diameter of 0.2 μm was adhered to the glass filter, and the mixture was filtered according to JIS L
After centrifugal dehydration according to the water swelling degree measuring method of JIS L-1015 and weighing (c), with the micro cellulose particles placed on the glass filter, the absolute dry electricity capacity (d ), and use the formula below to find .

a: Weight (Jl) of the glass filter and cellulose acetate membrane when pure water is heated in a furnace and subjected to centrifugal dehydration, b: Weight of the glass filter and cellulose acetate membrane in an absolutely dry state9), C: After centrifugal dehydration Weight of cellulose particles, glass filter, and cellulose acetate membrane G), d: Weight of cellulose particles, glass filter, and cellulose acetate membrane in an absolutely dry state q), <Average degree of polymerization> Determined according to the method described in JIS L-1015 Ta.

Copper value> Determined according to the method described in JIS-P-1801-1961.

R value> About 15g of viscose is dissolved in 7017ml of pure water, and further pure water is added to make the total amount 100. This viscose diluted solution 2C1lj was mixed with ion exchange resin (Amber-1ita
10 in a column packed with IRA 4100H type) 20-
Then, each 20 slj of pure water was passed through this column with rim-turning three times, and the entire amount was received in an Erlenmeyer flask. Approximately 3 g of powdered calcium carbonate was added to the ion exchange resin passing liquid, and while stirring, 10%-acetic acid"%N/2
0 Add 5 d of iodine, perform back titration with N/20-thiosulfuric acid using starch solution as an indicator, and calculate from the following formula.

A: N/20-thiosulfate consumption t (-j), B
: Consumption amount of N/20 sodium thiosulfate in blank test (
-7), C: Viscose sample type t (gr), D: Cellulose concentration (%) and salt point of viscose> A sodium chloride aqueous solution in which cellulose is regenerated when a small amount of viscose is added to a sodium chloride aqueous solution and shaken. (using the formula below) from the lowest concentration of

Observation method for viscose fine particles in a dispersion> A small amount (0,0019 or less) of the viscose liquid in the dispersion was taken with an extremely thin glass rod prepared in advance.

Immediately use a thin glass rod to tighten the
．． 003~o, o o s g was dropped to cover the dispersion liquid collected above to immobilize the viscose fine particles.

This is photographed and observed using an Olympus BH8 phase contrast microscope at a magnification of 400 times.

Example 1 Approximately 5 kg of a bulb made of coniferous wood was immersed in a 18% by weight caustic soda solution at 200 tVc for 1 hour at 20° C. and compressed to 2.8 times its size. The material was crushed and aged for 1 hour while increasing the temperature from 25°C to 50°C, and then 35% by weight of carbon disulfide (1,75kl?) was added to the cellulose, and sulfurized at 25°C for 1 hour to form xanthate. .

The xanthate was dissolved in a caustic soda aqueous solution to prepare viscose having a cellulose concentration of 9.0% by weight and a caustic soda concentration of 5.8% by weight. The viscose has an average polymerization [320,
The viscosity was 6000 centipoise and the gamma number was 37.8.

30 g of the viscose prepared above and an aqueous solution of polystyrene sulfonate as an anionic polymer compound (polymer concentration 21% by weight, molecular f 500,000; manufactured by Toyo Soda Co., Ltd., trade name P8-50) 2711 were placed in a 500 m flask. , the total amount was 300g.

At a liquid temperature of 30°C, stirring was performed at 4000 rpm for 10 minutes using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to generate fine viscose particles, and then with continued stirring,
Raise the liquid temperature from 30℃ to 70℃ in 15 minutes, and then increase the temperature to 70℃.
The mixture was maintained for 30 minutes to solidify the viscose particles. While continuing to stir, the mixture was neutralized and regenerated with 100 g/l of sulfuric acid to obtain a cellulose fine particle dispersion. The above dispersion was passed through an IGZ type glass filter to separate cellulose fine particles from the mother liquor, then desulfurized at 50°C with 2 tons of caustic soda aqueous solution, neutralized with 2 g/l sulfuric acid aqueous solution, and then washed with a large excess of water. After washing, it was washed with 50 cc of methanol and dried at 80° C. for 3 hours to obtain cellulose microparticles. Table 1 shows the results of measuring the viscose dispersion and cellulose particles using the above method.

Example 2 Using hardwood pulp as a raw material, viscose was prepared in the same manner as in Example 1 to obtain viscose with a cellulose concentration of 8.7% by weight, a caustic soda concentration of 5.4% by weight, a viscosity of 7400 centipoise, and a gamma value of 52. I got it.

Dispersion, coagulation, regeneration, washing, and drying were carried out in the same manner as in Example 1, with the amount of viscose and the aqueous solutions of various anionic polymer compounds varied as shown in Table 2. The shape, average particle diameter, and ratio within ±5 μm of the average particle diameter of each of the obtained cellulose microparticles were measured.

Example 3 A cellulose concentration of 9.3% by weight and a caustic soda concentration of 5.9% by weight were obtained using softwood pulp as a raw material in the same manner as in Example 1.
A viscose having a viscosity of 5,600 centipoise and a gamma value of 42 was obtained. Viscose particles were prepared in the same manner as in Example 1 by varying the amount of viscose and the molecular weight and concentration of the aqueous polystyrene sulfonate aqueous solution as shown in Table 3. Table 3 shows the shapes of the viscose particles during dispersion and solidification. Moreover, the shape of viscose particles when A14 is dispersed is shown in FIG.

Example 4 Various types of viscose were prepared in the same manner as in Example 1 using linter pulp as a raw material. Dispersion, coagulation, regeneration, washing, and drying were carried out in the same manner as in Example 1, with the concentrations of the viscose and sodium polystyrene sulfonate aqueous solutions varied as shown in Table 4.

Table 4 shows the shapes of the viscose particles during dispersion and solidification.

Example 5 Using hardwood pulp as a raw material, dispersion, coagulation, regeneration, washing and drying were carried out in the same manner as in Example 1, with the alkali concentration of viscose varied as shown in Table 5. Table 5 shows the shapes of the viscose particles during dispersion and solidification.

Table 5 Example 6 Using linter pulp as a raw material, the average polymerization degree and viscosity of viscose were changed as shown in Table 6, and dispersion, coagulation, regeneration, water washing and drying were carried out in the same manner as in Example 1. Ta.

Table 6 shows the shapes of the viscose particles during dispersion and solidification.

Table 6 Example 7 After putting 30 g of viscose prepared in Example 1 and 270 g of polystyrene/sulfo/acidic acid aqueous solution (molecular weight 500,000, polymer concentration 21% by weight) into a 5QQm beaker,
In the mixed solution, which was adjusted to 18°C and mixed in 262,144 layers in a static mixer with 18 elements of a static mixer manufactured by Kenix Inc. connected alternately left and right and at right angles, viscose was dispersed in a spherical shape with a maximum particle size of 21 μm.

Example 8 30 g of viscose same as Example 1 and polystyrene sulfonate (molecular weight 500,000, polymer concentration 21 weight*) 2
70 g was placed in a 500-flask for a total amount of 300 g. Stirring was carried out at 400 rpm for 10 minutes at a liquid temperature of 30° C., and the coagulation conditions were 32 to 36 as shown in Table 8. Post-treatment was carried out in the same manner as in Example 1, and particles were obtained in each case. Example 9 30 g of the same viscose as Example 1 and sodium polystyrene sulfonate (molecular weight 500,000, polymer concentration 21% by weight) 2
70. The lit was adjusted to a total volume of 3009 in a 5004 flask. As shown in I & 37 to 44 listed in Table 9, by changing the dispersion temperature and dispersion time, use a homomixer to
Viscose fine particles were obtained by stirring at oorpm. Table 9 shows the shape of the viscose particles during dispersion.

Example 10 Using hardwood bulb as a raw material, the gamma values of viscose were 32 (salt point 3.7), 45 (salt point 661), 82 (salt point 17.3), and 93 (salt point 20.2), respectively. All cellulose particles obtained under the same conditions as in Example 1 using viscose and sodium polystyrene sulfonate (molecular weight: 500,000, polymer concentration: 21 wt), which were adjusted to have the following properties, were spherical.

Example 11 An aqueous solution of viscose 309 obtained in Example 1 and sodium polystyrene sulfonate (polymer concentration 21% by weight, molecular weight 500,000) 270II was placed in a 5001 flask and the liquid temperature was 3.
Stirring was performed for 3 minutes at 4000 rpm using a homomixer at 0°C. To the obtained dispersion, l N H, 80,/aqueous solution of the above sodium polystyrene sulfonate = 1/1
(weight ratio) was added dropwise over 200,930 minutes while stirring to simultaneously perform coagulation and regeneration. The obtained cellulose particles were spherical and had an average particle size of 11.3 μm.

Example 12 30 g of viscose obtained in Example 1 was dissolved in 265 g of pure water. Put the diluted viscose into a 500Ilj flask, and mix it with a homomixer at 400O at a liquid temperature of 30°C.
While stirring at rpm, 5 g of sodium polyacrylate flakes having a molecular weight of 2 million were added. After stirring for 30 minutes, the liquid temperature was raised from 30° C. to 70° C. over 15 minutes to solidify the viscose fine particles, which were then regenerated, washed with water, and dried. The obtained cellulose particles were spherical and had an average particle size of 14.3 μm.

Example 13 A water-soluble polymer compound having a molecular weight of 50,000 was prepared by changing a copolymer of sodium acrylate and methyl acrylate as shown in Table 1O. While maintaining a 15% aqueous solution 2709 of these polymer compounds at 20C and stirring at 4ooorpm, 30 g of the viscose obtained in Example 1 was added thereto, and the mixture was stirred for 5 minutes.

The dispersion state of viscose in the mixture was observed using the photographic method described above.

Table 10 Comparative Example 1 A cellulose concentration of 9.0% by weight and a caustic soda concentration of 5.0% were prepared from softwood pulp in the same manner as in Example 1. L%, viscosity 5900
Viscose with centipoise and gamma value of 43 was obtained. In a flask with a capacity of 5QQs+j, add 300% liquid paraffin (viscosity 170-180 centipoise at 20°C, manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.).
Add the viscose 33 and 9 mentioned above under the stirring conditions shown in Table 11 at 30°C, and then stir for 20 minutes to disperse the viscose, then reduce the liquid temperature from 30°C to 80°C without stirring. The temperature was raised to .degree. C. over 20 minutes, and the mixture was heated at 80.degree. C. for 1.5 hours to form viscose particles. Thereafter, the viscose particles were washed with xylene, methanol and hot water. The viscose particles were dispersed in a sulfuric acid aqueous solution of 200-49Ii/, stirred for 1 hour, neutralized and regenerated to obtain a cellulose particle dispersion. Post-treatment was performed in the same manner as in Example 1 to obtain cellulose particles. Table 11 shows the results of microscopic observation of the cellulose particles obtained. fjgl1
The average particle size in the table is the result of measurement of 100 cellulose particles, but no particle with an average particle size of 20 μm or less was obtained under any conditions.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the particle size distribution of cellulose particles of Example 1 of the present invention. FIG. 2 is a photograph showing the dispersion state of viscose particles for producing cellulose particles of the present invention. FIGS. 3 and 4 are photographs of cellulose particles of the present invention at different magnifications. FIGS. 5 and 6 are photographs of other cellulose particles of the present invention at different magnifications. Rumo 6

Claims (1)

[Claims] 1. (a) consisting essentially of type II cellulose; (b)
The degree of crystallinity determined by line diffraction is in the range of 5 to 30%, (c) the average particle size consists essentially of spherical or oblate particles with an average particle size of 20 μm or less, and (d) the particle size is an average particle. Micro cellulose particles characterized in that they have a particle size distribution in which particles in the particle size range of diameter (μm) ±5 μm account for 70% by weight or more of all particles. 2. Micro cellulose particles according to claim 1, having a crystallinity in the range of 10 to 28%. 3. Micro cellulose particles according to claim 1, having a crystallinity in the range of 15 to 26%. 4. The microcellulose particles according to claim 1, which consist essentially of spherical or oblong spherical particles having an average particle diameter of 1 to 18 μm. 5. The micro cellulose particles according to claim 1, which essentially consist of spherical or prolong spherical particles having an average particle diameter of 1.5 to 15 μm. 6. The projection of a long spheroidal particle is an ellipse, an elongated circle,
The micro cellulose particles according to claim 1, which are peanut-shaped or egg-shaped. 7. Micro cellulose particles according to claim 1, which have a particle size distribution in which particles having a particle size in the average particle size (μm) ±5 μm account for 75% by weight or more of the total particles. 8. The micro cellulose particles according to claim 1, having a particle size distribution in which particles having a particle size in the average particle size (μm) ±5 μm account for 80% by weight or more of the total particles. 9. The micro cellulose particles according to claim 1, having a particle size distribution in which particles having a particle size within the average particle size (μm) ±5 μm account for 85% by weight or more of all particles. 10. The micro cellulose particles according to claim 1, having a particle size distribution in which particles having a particle size in the average particle size (μm) ±5 μm account for 90% by weight or more of all particles. 11. Micro cellulose particles according to claim 1, wherein the degree of polymerization of cellulose is in the range of 100 to 700. 12. Micro cellulose particles according to claim 1, which have a water swelling degree in the range of 100 to 500%. 13. The micro cellulose particles according to claim 1, wherein the cellulose has a copper value of 3 or less. 14. Pore diameter measured by mercury porosimeter method: 0.0
The volume of pores of 1 to 0.5 μm is 60 × 10^-^3cc/
The micro cellulose particles according to claim 1, which have a particle size of less than g. 15. Microcellulose particles obtained by mixing at least two types of microcellulose particles according to claim 1, which have mutually different average particle diameters and/or particle size distributions. 16, (1), Mixing viscose and a water-soluble anionic polymer compound to produce a fine particle dispersion of viscose; (2), (i) heating the above dispersion, or heating the above dispersion; The viscose in the dispersion is coagulated by mixing with a coagulant and then neutralized with an acid to produce fine particles of cellulose; or (ii) the dispersion is coagulated and neutralized with an acid to form cellulose particles. A method for producing microcellulose particles, which comprises: producing microparticles, and then (3) separating the cellulose microparticles from the mother liquor, and optionally desulfurizing, pickling, washing with water, or drying. 17. The method according to claim 16, wherein the viscose has a cellulose concentration of 3 to 15% by weight. 18. The alkaline concentration of viscose is 2 as caustic soda.
17. The method of claim 16, wherein the amount is ~15% by weight. 19. The method according to claim 16, wherein the ratio of alkali as caustic soda to cellulose of viscose is 40 to 100% by weight. 20. The method according to claim 16, wherein the viscose has a gamma number of 30 to 100. 21. The viscosity of viscose is 50-20 at 20°C,
17. The method of claim 16, wherein the oscillation rate is 0,000 centipoise. 22. The method according to claim 16, wherein the viscose has a salt point of 3 to 20. 23. Claim 16, wherein the water-soluble anionic polymer compound has, as an anionic group, a sulfonic acid group, a phosphonic acid group, or a carboxylic acid group in the form of a free acid or a salt. the method of. 24. At least the water-soluble anionic polymer compound is selected from the group consisting of vinyl sulfonic acid, styrene sulfonic acid, methylstyrene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, acrylamide methylpropane sulfonic acid, and salts thereof. 17. The method of claim 16, containing polymerized units of one type of monomer. 25, the water-soluble anionic polymer compound is acrylic acid,
17. The method according to claim 16, which contains polymerized units of at least one monomer selected from the group consisting of methacrylic acid, styrene carboxylic acid, maleic acid, itaconic acid, and salts thereof. 26. Claim 16, wherein the water-soluble anionic polymer compound contains polymerized units of at least one monomer selected from the group consisting of styrenephosphonic acid, vinylphosphonic acid, and salts thereof. Method described. 27. The method according to claim 16, wherein the water-soluble anionic polymer compound is a homopolymer or copolymer containing at least 20 mol % of polymerized units of the above monomers. 28. The method according to claim 16, wherein the water-soluble anionic polymer compound has a number average molecular weight of at least 5,000. 29. The method according to claim 16, wherein the water-soluble anionic polymer compound has a number average molecular weight of 10,000 to 3,000,000. 30. The method according to claim 16, wherein the water-soluble anionic polymer compound is used as an aqueous solution. 31. The method according to claim 16, wherein the water-soluble anionic polymer compound is used as an aqueous solution containing 0.5 to 25% by weight. 32. The method according to claim 16, wherein the water-soluble anionic polymer compound is used as an aqueous solution of 2 to 22% by weight. 33. The method according to claim 16, wherein the water-soluble anionic polymer compound is used as an aqueous solution having a viscosity of 30,000 to 50,000 centipoise at 20°C. 34. The method according to claim 16, wherein the water-soluble anionic polymer compound is used as an aqueous solution having a viscosity of 50,000 to 30,000 centipoise at 20°C. 35. The method according to claim 16, wherein viscose and a water-soluble anionic polymer compound are mixed at a temperature lower than the boiling point of carbon disulfide. 36. The method according to claim 16, wherein viscose and a water-soluble anionic polymer compound are mixed at a temperature of 0 to 40°C. 37. The method according to claim 16, wherein the viscose and the water-soluble polymer compound are mixed by mechanical stirring. 38. Claim 16, in which the viscose and the water-soluble polymer compound are mixed using a static mixer.
The method described in section. 39. The method according to claim 16, wherein the viscose and the water-soluble polymer compound are mixed in a ratio of 0.3 to 100 parts by weight of the water-soluble polymer compound per 1 part by weight of cellulose. 40. The method according to claim 16, wherein the viscose and the water-soluble polymer compound are mixed in a ratio of 1 to 45 parts by weight of the water-soluble polymer compound per 1 part by weight of cellulose. 41. The method according to claim 16, wherein viscose and a water-soluble polymer compound are mixed in a ratio of 4 to 20 parts by weight of the water-soluble polymer compound per 1 part by weight of cellulose. 42. The method according to claim 16, wherein the viscose fine particles in the dispersion produced in step (1) have a substantially spherical shape with an average particle size of 30 μm or less. 43. Claim 16, wherein the coagulation reaction in step (2) is carried out while adding a mixing operation to the produced dispersion.
The method described in section. 44. Claim 16, wherein the solidification by heating in step (2)(i) is carried out at a temperature equal to or higher than the boiling point of carbon disulfide.
The method described in section. 45. Solidification by heating in step (2) (i) above at 50°
17. A method according to claim 16, carried out at a temperature of -90<0>C. 46. Coagulation with coagulant in step (2) (i) above from 0 to
17. The method according to claim 16, carried out at a temperature of 40<0>C. 47. The coagulant used in step (2) (i) above is a lower aliphatic alcohol, an alkali metal salt or alkaline earth metal salt of an inorganic acid, an inorganic acid, an organic acid, or a combination thereof, or a water-soluble polymer containing them. 17. The method according to claim 16, which is in combination with a compound. 48. The method according to claim 16, wherein the acid used for neutralization in step (2)(i) is a strong inorganic acid. 49. Coagulation and neutralization in step (2) (ii) above from 0 to
17. The method according to claim 16, carried out at a temperature of 40<0>C. 50. The method according to claim 16, wherein the acid used for coagulation and neutralization in step (2)(ii) is a strong inorganic acid. 51. The method according to claim 50, wherein the strong inorganic acid is hydrochloric acid or sulfuric acid.