JPS6279231A - Production of minute cellulose particle - Google Patents

Abstract

PURPOSE:To obtain the titled particle suitable as a diluent for pharmaceuticals, vehicle for cosmetics or food additive, by mixing viscose with a specific polyethylene glycol (derivative) and coagulating the resultant dispersion of fine particles under a specific condition. CONSTITUTION:(A) Viscose is mixed with (B) a water-soluble polyethylene glycol (derivative) having a number-average molecular weight of >=1,500 and a dispersion of fine viscose particles is produced at >=55 deg.C. The viscose in the dispersion is coagulated either by heating the dispersion at a temperature equal to or higher than the above temperature or by mixing the dispersion with (C) a coagulant. Minute cellulose particles are produced either by neutralizing the coagulated dispersion with an acid or by coagulating the dispersion with an acid and neutralizing the product. The produced minute particles are separated from the mother liquor and, if necessary, subjected to desulfurization, pickling, washing with water or drying to obtain the objective particles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) More specifically, the present invention relates to a method for producing microcellulose particles, and more particularly relates to a method for producing microcellulose particles consisting essentially of recycled cellulose.

(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, solvents, 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 cellulonise is produced by selecting particularly high-purity purified Nosorp, which is hydrolyzed with mineral acid under certain conditions to wash and remove the amorphous regions, and then ground.
It is known that it can be produced by refining and drying (see the pamphlet entitled "Crystalline Cellulose, Avicel ■" published by Asahi Kasei Kogyo Co., Ltd. on May 1980).According to the pamphlet, furthermore, The above-mentioned high-purity microcrystalline cellulose is chemically a natural cellulose, that is, a type cellulose itself, and has, for example, a small average particle size of 6 μm to an average particle size of 40 μm or about 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) was found to have relatively good crystallinity with a degree of crystallinity of about 51 to 55%.

JP-A-48-21758 discloses that the gamma value 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 50 to 46 meshes (500 to 590 μm).
m) regenerated cellulose granules are described.

Japanese Patent Publication No. 56-21.761 describes a method in which viscose is extruded from a discharge port, the continuous flow is naturally changed into a droplet flow in the air, and the droplets are supplied to a coagulation regeneration bath as nearly spherical droplets. Disclosed. The same gazette states that 16
~17. It is described that cellulose granules with a '0 mesh (88-1168 μm) can be obtained.

Japanese Patent Publication No. 57-7162 discloses hollow regenerated cellulose fine particles having a large void in the center. It is described that the granular material has an apparent density of 1141/era" or less and 1) a mesh size of 16-170 mesh.

Japanese Unexamined Patent Publication No. 48-60755 includes the aforementioned Japanese Unexamined Patent Publication No. 48-60755.
By using a coagulation regeneration bath with a higher acid concentration and mirabilite concentration than the method disclosed in Japanese Patent No. 21758, υ, 16~
A method of making 170 mesh porous regenerated cellulose particles is disclosed.

Japanese Patent Publication No. 49-89.748 discloses that recycled cellulose fibrous material is hydrolyzed, dried, and crushed to obtain a material with a length/diameter ratio of 20/1 to 2/1 (1) and a length of A method for producing cellulose powder of 11151 or less is disclosed.

JP-A-57-212,251 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 50 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 of ~650 μm occupying 85 volumes (Example 1) are obtained.

Japanese Patent Publication No. 55-59565 discloses that a solution of cellulose triacetate in methylene chloride or chloroform is dropped into an aqueous medium in which a dispersing agent such as gelatin or previnyl alcohol is dissolved, while stirring, and heated. A method for producing cellulose spherical particles by forming spherical particles of cellulose acetate and then saponifying the same is disclosed. Examples of the same publication disclose cellulose particles of 30 to SOO μm.

Japanese Patent Publication No. 55-40618 discloses a method for producing cellulose particles of 50 to 500 .mu.m from cellulose ester from a field of cellulose triacetate in exactly the same manner as described above.

JP-A-55-2A763 discloses a method for producing microspherical particles by spray-drying a solution in which cellulose fatty acid ester is dissolved in a mixed solvent of three or more solvents having a boiling point difference of 50° C. or more. There is.

JP-A-57-159.801 discloses that cellulose is dissolved in a DMSO solution of paraformaldehyde, the resulting solution is dispersed in a liquid, and mixed with a cellulose coagulant to form a cellulose dispersion. A method is disclosed for producing granular cellulose glue by agglomerating droplets and optionally regenerating 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 No. 57-219.555 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 and 2000 rpm. 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-48-5-752 discloses a method for producing cellulose powder by treating cellulose with tetrahydrofuran and 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.

[Departure F! [Problems to be Solved by A] An object of the present invention is to provide a novel method for producing microscopic cellulose particles consisting essentially of regenerated cellulose or type II cellulose.

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 high molecular weight polyethylene glycol or polyethylene glycol derivative to produce a viscose dispersion.

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 objects and advantages of the present invention are as follows: (1) Viscose and water-soluble polyethylene glycol or polyethylene glycol having a number average molecular weight of 1.500 or more. The derivatives are mixed to produce a fine particle dispersion of viscose at a temperature of 55° C. or higher, and (2), (1) the dispersion is further heated at a temperature equal to or higher than the temperature at which the dispersion is produced. coagulating the viscose in the dispersion by heating or mixing the dispersion with a coagulant and then neutralizing with an acid to produce cellulose microparticles; or (ii) coagulating the dispersion with an acid. and neutralization to produce cellulose fine particles, and then (3) separating the cellulose fine particles from the mother liquor, and optionally desulfurizing, pickling, water washing, or drying. achieved by law.

According to the method of the present invention, the first step produces dispersed viscose fine particles, the second step produces cellulose fine particles, and the third step separates the cellulose fine particles from the mother liquor.

The first step of producing a fine particle dispersion of viscose is carried out by mixing viscose and a water-soluble polyethylene glycol or polyethylene glycol derivative having a number average molecular weight of 1500 or more.

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

The gamma value is 50-100, more preferably 55-90. The salt point is 5-20, more preferably 4-18. The cellulose concentration is between 5 and 15 wt-1, preferably 5
~13% by weight. Alkali concentration is 2-15% by weight,
More preferably, it is 4 to 15% by weight. The weight proportion of alkali (as caustic soda) for the cellulose concentration of 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 2 (LOOO centipoise, more preferably 80
~IEl, 000 centipoise.

The pulp source for bis;-s is preferably linter pulp, and may be made from softwood or hardwood.The average degree of polymerization of viscose as cellulose is usually 110 to 1.000.

The high molecular weight polyethylene glycol or polyethylene glycol derivative used has a number average molecular weight of 91,500 or more as described above, preferably 1.50.
It has a number average molecular weight of 0 to 40QOOO.

As a polyethylene glycol derivative, for example, only the hydroxyl group at one end of polyethylene glycol has 1 to 1 carbon atoms.
8 alkyl group, a phenyl group substituted with an alkyl group having 1 to 18 carbon atoms, or a water-soluble compound blocked with an acyl group having 2 to 18 carbon atoms or an A-B-A' type block copolymer (A, A' are the same or different and represent a polyethyl oxide block, and B represents a polypropylene oxide block) are preferably used. More specifically, for example, polyethylene glycol monomethyl ether, polyethylene glycol monolauryl ether, polyethylene glycol monocetyl ethyl; polyethylene glycol monocetyl ethyl ether (f, n, d); polyethylene glycol monononylphenyl ether; polyethylene glycol monoacetate)1. T? lj ethylene glycol monolaurate; and polyoxyethylene block-polyoxypropylene block-polyoxyethylene block.

Among polyethylene glycol and its derivatives, polyethylene glycol is more preferable, and the number average molecular weight is 0.
Those having a number average molecular weight of a00 to 201111.000 are particularly preferred, those having a number average molecular weight of a000 to 10G,000 are particularly preferred, and those having a number average molecular weight of ICLOO to 5 CLOOO are particularly preferred. The polyethylene glycol derivative preferably has a number average molecular weight of 1.500 to 16.000.

According to the method of the present invention, viscose and water-soluble high molecular weight polyethylene glycol or its derivative are first mixed. Any means can be used for mixing as long as a viscose fine particle dispersion is produced. For example, mechanical stirring using stirring blades or baffles, ultrasonic stirring, or mixing using a static mixer may be used alone or in combination. can do.

The water-soluble high molecular weight polyethylene glycol or its derivative is preferably used as an aqueous solution, more preferably the concentration of the polyethylene glycol or its derivative is 05 to 6.
0% by weight, particularly preferably 5-55% by weight, especially 10-55% by weight
It is used as a 40% by weight aqueous solution.

h, ~24 parts by weight, particularly 8 to 16 parts by weight, are used and mixed. Although there is no particular restriction on the temperature during mixing, it is desirable to carry out the mixing at a temperature lower than the temperature at which a fine particle dispersion of viscose is produced. The viscose microparticle dispersion is produced at temperatures above 55°C. At temperatures below 55° C., it is not possible to obtain a basic viscose microparticle dispersion capable of providing the desired microcellulose particles.

According to the method of the present invention, the viscose fine particle dispersion produced in the first step is then neutralized 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.

Further, the coagulation reaction is carried out at a temperature equal to or higher than the temperature at which the dispersion is produced.

Both coagulation by heating and coagulation using a coagulant are preferred.
It is carried out at a temperature of 16oC to 90C.

As the coagulant, for example, alkaline earth salts or alkaline earth metal salts of inorganic acids, inorganic acids, organic acids, or combinations thereof, or combinations thereof with water-soluble polyethylene glycol or polyethylene glycol derivatives 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 NaC.
1°Na salt such as Na2SO4, K! Salts such as S04 are preferred, and alkaline earth metal salts such as M
Mg salts such as g5O, and Ca salts such as CaCl2 are preferred. The organic acid is preferably a carboxylic acid or a sulfonic acid, such as formic acid, acetic acid, glopionic acid, benzenesulfonic acid, toluenesulfonic acid, maleic anhydride, malic acid, oxalic acid, etc.

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.

When a combination of polyethylene glycol or its derivatives is used as the coagulant, the addition of the coagulant can prevent the concentration of polyethylene glycol or its derivatives in the system from decreasing. It has the advantage that coagulation can be carried out stably.

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, as described above, the second step of coagulation and neutralization can 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, 60°C to 90°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. The separation of fine particles from the mother liquor can be carried out, for example, by filtration, centrifugation, etc. Desulfurization can be carried out using an aqueous alkali solution such as caustic soda or 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 present invention, microcellulose X particles consisting essentially of n-type cellulose can be produced.

Preferred microcellulose particles obtained by the present invention are:
For example, (a) consists essentially of n-type cellulose; (b)
It can be characterized by having a crystallinity in the range of 5 to 65% as determined by X-ray diffraction, and (c) consisting essentially of spherical or prolate particles with an average particle size of 200 μm or less. .

The microcellulose particles first consist essentially of n-type cellulose, ie regenerated cellulose. Therefore, cellulose fine particles made of natural cellulose, that is, n-type cellulose, are completely different from the above-mentioned fine particles. As is well known, n-type cellulose and n-type cellulose can be distinguished by X-ray diffraction. In the X11 diffractograms of type (2) cells o- and e, there is substantially no diffraction peak at a diffraction angle (2θ) of 15°, which clearly exists in n-type cellulose.

The microcellulose particles obtained according to the present invention are secondly characterized by the degree of crystallinity determined by X-ray diffraction, and have a degree of crystallinity of 5 to 55. The microcellulose particles preferably have a crystallinity of 10 to 50%, more preferably 15 to 28%. This minute cellulose is not amorphous but crystalline as specified by the degree of crystallinity mentioned above.

Fifth, the micro cellulose particles have an average particle size of 200
It consists essentially of spherical or oblong spheroidal particles of less than μm ml. According to the method of the present invention, it is also possible to produce extremely fine particles such as fine cellulose particles consisting essentially of spherical or prolong spherical particles having an average particle size of 20 μm or less.

The term "spheroidal" as used herein is a concept that includes particles whose projected view or plan view has a shape such as an ellipse, an elongated nine-round shape, a peanut shape, or an oval shape. The micro cellulose particles are spherical or oblong as described above, and are therefore different from particles that are rounded or irregularly shaped. When producing long spherical microcellulose particles according to the method of the present invention described above, when moving from dispersion in the first step to coagulation in the second step, viscose and polyethylene glycol or its derivatives are mixed too vigorously. It becomes easier to form when solidified.

The physical properties characterizing the above-mentioned micro cellulose particles are as follows:
Additionally, the following can be mentioned:

The cellulose that makes up the micro cellulose particles is usually 10
Many of these microcellulose particles exhibit a degree of polymerization in the range of 0 to 700. Many of these microcellulose particles have a copper value of 3 or less, which is measured and defined by the method described below.
The degree of water swelling measured and defined by the method described below is 100.
~500%.

As mentioned above, the micro cellulose particles obtained by the method of the present invention are fine, and because they are cellulose, they are relatively stable against chemicals and are non-toxic, so they can be used as diluents for various pharmaceuticals and fillers for cosmetics, for example. Alternatively, it can be used in a wide range of industrial fields as a food additive.

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.

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

Crystallinity (a) = -X 100 T' Here, T' = ((a + c) - b) x KK = (L896
(Non-drying scattering correction coefficient of cellulose) & Area of diffraction curve (2θ = 5 to 45°) of non-grade starch, b = Area of air scattering curve (2θ = 5 to 45°), C: Sangle Area of the diffraction curve (2θ = 5 to 45°), <Water swelling degree> Amount of micro cellulose particles 1. After immersing Of in pure water with an amount more than 20 times the amount of particles, the cellulose particle mixture was allowed to naturally pass through a glass filter in which a cellulose acetate membrane with a hole diameter of 111L2 μm was adhered to the glass filter.
After centrifugal dehydration according to the water swelling degree measurement method of JIS L-1015, and weighing (C), with the micro cellulose particles placed on the glass filter, the absolute dry weight ( d) is calculated using the following formula.

(d-b-a: Weight of the lath filter and cellulose acetate membrane when pure water is filtered and centrifugally dehydrated (f), b: Weight of the lath filter and cellulose acetate membrane in an absolutely dry state f: kcf), C: Weight of cellulose particles, glass filter and cellulose acetate membrane after centrifugal dehydration (r), d: Weight of cellulose particles, glass filter and cellulose acetate membrane in an absolutely dry state (f), average degree of polymerization > Determined according to the method described in JIS L-1015.

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

γ value> About 2.5rr of viscose is dissolved in 70ml of pure water, and further pure water is added to make a total volume of 100ml.This viscose diluted solution of 20ml is mixed with an ion exchange resin (AmberllteIRA).
410 0H type) 10 mt in a column packed with 20-
The column was then passed through the column at a flow rate of /min, and then each 20-mL pure water was passed through this column repeatedly five times, and the entire amount was received in an Erlenmeyer flask. Approximately 50% of powdered calcium carbonate is added to the liquid passing through the ion exchange resin.
2 and further stirred with 10% vinegar [5 Tnt, N/
Add 5 Tst of 20 iodine, perform back titration with N/20-sodium thiosulfate using starch solution as an indicator, and calculate from the following formula.

XD A: Consumption amount of N/20-sodium thiosulfate (-), B: Consumption amount of N/20-sodium thiosulfate in blank test (G), C: Viscose sample weight Cfr), D Cellulose concentration of niviscose ( b) Salt point> Calculate using the formula below from the minimum concentration of the sodium chloride solution at which cellulose will regenerate when a small amount of viscose is added to the sodium chloride solution and shaken.

Average particle size measurement method> Cellulose particles were measured using Olynoces B I (S N phase t[
The photograph was taken with a microscope at a magnification of 400 times, the length of 100 cellulose particles was measured, and the average particle diameter was calculated from the results.

Example 1 Pulp made of coniferous wood was immersed in 200 tons of 18% by weight caustic soda solution at about 54,120° C. for 1 hour and compressed to 2.8 times its size. Grind for 1 hour while raising the temperature from 25℃ to 50℃.
Then, the xanthate was dissolved in cellulose with an aqueous caustic soda solution to prepare viscose having a cellulose concentration of 9.0% by weight and a caustic soda concentration of 5.5% by weight. The viscose had an average degree of polymerization of 504, a viscosity of 7,200 centipoise, and a saury value of 57.0.

Aqueous solution of viscose 2402 and polyethylene glycol prepared above (polymer concentration 50% by weight, molecular weight 2 to 0D)
D) Put 60r into a 500-flask and make the total amount 500
It was set as 2.

The liquid was heated to 40°C using a laboratory stirrer (MODELLR).
-51B manufactured by Yamato Scientific Co., Ltd.) Stirring at 1000 rpm for 10
The temperature of the solution was raised from 40°C to 80'C in 15 minutes with continuous stirring to form a viscose dispersion, and the mixture was maintained at 80°C for 50 minutes to coagulate fine viscose particles. . 100f/l with continuous stirring
This was neutralized and regenerated with sulfuric acid to obtain a cellulose fine particle dispersion. The above dispersion was passed through an IG4 type glass filter to separate cellulose fine particles from the mother liquor, and then heated at 50°C for 2 hours.
F/ was desulfurized with 2 tons of caustic soda aqueous solution, neutralized with 2 tons/l of sulfuric acid aqueous solution, washed with a large excess of water, and then
Washed with CC methanol, dried at 80°C for 5 hours,
Obtain cellulose microparticles.

Table 1 shows the results of measuring cellulose particles using the above method.

Table 1 Example 2 Using hardwood Noralug as a raw material, the gamma values of viscose were 52 (salt point F), 45 (salt point 6.1), 82 (salt point 17.3), and 95 (salt point F), respectively. Viscose and polyethylene glycol (molecular weight 2Q) adjusted to have a point 2CL2)
, 000, polymer concentration 50% by weight), Example 1
All of the cellulose particles obtained in the same manner were spherical.

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 2. Table 2 shows the shape of the viscose particles upon solidification.

Table 2 Example 4 Using linter pulp as a raw material, the average polymerization degree and viscosity of viscose were changed as shown in Table 5, and dispersion, coagulation, regeneration, water washing and drying were carried out in the same manner as in Example 1. Ta.

Table 3 shows the shape of the viscose particles upon solidification.

Table 3 Example 5 Using hardwood pulp as a raw material, viscose was prepared in the same manner as in Example 1, with a cellulose concentration of 7% by weight, a caustic soda concentration of 5.4% by weight, and a viscosity of 7400 centipoise.
Viscose with a gamma value of 52 was obtained.

, the above amount of viscose and various polyethylene glycols (
POE) or its derivatives were varied as shown in Table 4, and dispersion, coagulation, regeneration, water washing and drying were carried out in the same manner as in Example 1. The shape and average particle diameter of each of the obtained cellulose microparticles were measured.

Example 6 A cellulose concentration of 9.3% by weight and a caustic soda concentration of 5.9% by weight were prepared 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. Example 1 The amount of viscose and the molecular weight and concentration of polyethylene glycol were changed as shown in Table 5.
Viscose particles were prepared in the same manner as described above. Table 5 shows the shape of the viscose particles upon solidification.

Table 5 Example 7 Various types of viscose were prepared using linter lip as a raw material in the same manner as in Example 1. Dispersion, coagulation, regeneration, water washing and drying were carried out in the same manner as in Example 1, with the concentrations of the viscose and polyethylene glycol aqueous solution (molecular weight 20.000) being varied as shown in Table 6.

Table 6 shows the shape of the viscose particles upon solidification.

Example 8 60f of viscose obtained in Example 1 was dissolved in 180f of pure water. Put the diluted viscose into a 500-ml flask and mix with a laboratory stirrer 1100 or so at a liquid temperature of 40°C.
60f of polyethylene glycol flakes with a molecular weight of 2 (LO00) were added while stirring at 50%.
After stirring for several minutes, the liquid temperature was raised from 40°C to 80°C in 15 minutes to produce a viscose dispersion and coagulate the fine particles, which were recycled, washed with water, and dried to produce cellulose particles that were light bulb-shaped. The average particle size was IL 5 μm.

Example 9 Viscose (approximately 200) made in Example 1 6゜2
Polyethylene glycol aqueous solution (molecular weight 2
0,000. The mixture was placed in a 240f (concentration: 50% by weight) and heated for 30 minutes while stirring with a lab stirrer at 11,000 rpm. The obtained viscose fine particles had an average particle diameter of 11.5 μm.
It was spherical.

Example 10 Viscose 60f made in Example 1 was added to a polyethylene glycol aqueous solution (molecular weight zn, aoo, 6 degrees 50% by weight)
Put 240 in it and put it in the Lagos stirrer 1100 at 40℃.
Orp stirring was performed for 10 minutes. The temperature was raised from 40°C to 60°C in about 10 minutes, and at this point when true spherical fine particles of viscose were formed, a polyethylene glycol aqueous solution containing sulfuric acid concentration of 5 f/l (molecular weight 2 to 000, concentration 30
Heavy gong chi) 240? was heated to 60° C., and then heated for 50 minutes to obtain coagulated viscose fine particles.

What is the average diameter of the viscose particles obtained in this way? ,
The surface was smooth at 8°μm.

Claims (1)

[Claims] 1. (1) Viscose and water-soluble polyethylene glycol or polyethylene glycol derivative having a number average molecular weight of 1,500 or more are mixed to form a fine particle dispersion of viscose at a temperature of 55°C or higher. (2), (i) the dispersion by further heating the dispersion at a temperature equal to or higher than the temperature at which the dispersion was produced, or by mixing the dispersion with a coagulant; The viscose in the liquid is coagulated and then neutralized with an acid to produce cellulose microparticles, or (ii) the dispersion is coagulated and neutralized with an acid to produce cellulose microparticles, and then (3) A method for producing microcellulose particles, which comprises separating the cellulose microparticles from the mother liquor, and, if necessary, desulfurizing, pickling, washing with water, or drying. 2. The method according to claim 1, wherein the viscose has a cellulose concentration of 3 to 15% by weight. 3. The alkaline concentration of viscose is 2~2 as caustic soda.
15. A method according to claim 1, wherein the amount is 15% by weight. 4. The method according to claim 1, wherein the ratio of alkali as caustic soda to cellulose of viscose is 40 to 100% by weight. 5. The method according to claim 1, wherein the viscose has a gamma value of 30 to 100. 6. The viscosity of viscose is 50-20.0 at 20℃
5. A method according to claim 4, wherein the oscillation rate is 0.00 centipoise. 7. The method according to claim 1, wherein the viscose has a salt point of 3 to 20. 8. The number average molecular weight of polyethylene glycol or polyethylene glycol derivative is 1,500 to 400,000
The method according to claim 1. 9. The number average molecular weight of polyethylene glycol is 6,00
2. A method according to claim 1, wherein the number is between 0 and 200,000. 10. The method according to claim 1, wherein the polyethylene glycol derivative has a number average molecular weight of 1,500 to 16,000. 11. In a polyethylene glycol derivative, only the hydroxyl group at one end of polyethylene glycol is blocked with an alkyl group having 1 to 18 carbon atoms, a phenyl group substituted with an alkyl having 1 to 18 carbon atoms, or an acyl group having 2 to 18 carbon atoms. or a block copolymer of the A-B-A' type (A, A' are the same or different and represent a polyethylene oxide block, and B represents a polypropylene oxide block). The method described in paragraph 1. 12. The method according to claim 1, wherein the water-soluble polyethylene glycol or polyethylene glycol derivative is used as an aqueous solution. 13. The method according to claim 1, wherein the water-soluble polyethylene glycol or polyethylene glycol derivative is used as an aqueous solution of 0.5 to 60% by weight. 14. The method according to claim 1, wherein the water-soluble polyethylene glycol or polyethylene glycol derivative is used as a 5-55% by weight aqueous solution. 15. The method according to claim 1, wherein the viscose and polyethylene glycol or polyethylene glycol derivative are mixed by mechanical stirring. 16. The method according to claim 1, wherein the viscose and polyethylene glycol or polyethylene glycol derivative are mixed using a static mixer. 17. The method according to claim 1, wherein viscose and polyethylene glycol or a polyethylene glycol derivative are mixed in a ratio of 1 to 30 parts by weight of polyethylene glycol or polyethylene glycol derivative per 1 part by weight of cellulose. 18. The method according to claim 1, wherein viscose and polyethylene glycol or a polyethylene glycol derivative are mixed in a ratio of 2 to 28 parts by weight of polyethylene glycol or polyethylene glycol derivative per 1 part by weight of cellulose. 19. The method according to claim 1, wherein the coagulation reaction in step (2) is carried out while adding a mixing operation to the produced dispersion. 20. Solidification by heating in step (2) (i) above at 60°C
A method according to claim 1, carried out at a temperature of -90<0>C. 21. Coagulation with coagulant in step (2) (i) above at 60°C
A method according to claim 1, carried out at a temperature of -90<0>C. 22. The coagulant used in step (2) (i) above is 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 polyethylene glycol or a polyethylene glycol derivative that is water-soluble with them. The method according to claim 1, which is a combination with. 23. The method according to claim 1, wherein the acid used for neutralization in step (2)(i) is a strong inorganic acid. 24, coagulation and neutralization in step (2) (ii) above at 60%
2. A method according to claim 1, which is carried out at a temperature between 90°C and 90°C. 25. The method according to claim 1, wherein the acid used for coagulation and neutralization in step (2)(ii) is a strong inorganic acid. 26. The method according to claim 25, wherein the strong inorganic acid is hydrochloric acid or sulfuric acid.