JPS6399237A - Fine cellulose particle and production thereof - Google Patents

Abstract

PURPOSE:To obtain the titled fine particles, consisting of cellulose II, relatively stable to chemicals and suitable for liquid chromatographic packings, etc., by removing part of water from specific coagulated fine viscose particles, neutralizing the particles and converting the viscose into cellulose. CONSTITUTION:Part of water is removed from coagulated fine viscose particles consisting of (A) 10-60wt% cellulosic component, (B) 90-35wt% water and (C) 0-5wt% water-soluble high polymer, e.g. sodium polyacrylate, etc., using, e.g. a saturated sodium sulfate solution. The resultant particles are then neutralized and regenerated with sulfuric acid, etc., to convert the viscose into cellulose. The above-mentioned fine particles are then separated and, as necessary, subjected to removal of the component (C), desulfurization, washing and drying to provide the aimed fine cellulosic particles in a (spheroidal) spherical form with <=300mu average particle diameter, consisting substantially of cellulose II and having 5-35wt% crystallinity (measured by X-ray diffractometry) and <=3,000 excluded limiting molecular weight measured by using PEG.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to microcellulose particles and a method for producing the same.

More specifically, the present invention relates to micro cellulose particles that are essentially made of recycled cellulose and have an exclusion limit molecular weight of 3000 or less for polyethylene glycol in liquid chromatography, 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. Known to be manufactured by Mukasei Kogyo Co., Ltd., published on March 1, 1981, [crystalline cellulose,
(See the pamphlet titled "Avisel ■"). According to the same pamphlet, the high-purity microcrystalline cellulose is chemically natural cellulose, that is, type I cellulose itself, and has, for example, a small average particle size of 6 μm to 40 μm or about 120 μm in average particle size. It can be seen that even large ones are commercially available. According to research conducted by the present inventors, 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 r 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 30 to 46 meshes (300 to 590 μm).
m) regenerated cellulose granules are described.

Japanese Patent Publication No. 56-21,761 discloses that 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. A method is disclosed. The publication describes that cellulose granules with a size of 16 to 170 meshes (88 to 1168 μm) can be obtained by the same method.

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 0.4 f/cm" and 16 to 170 mesh.

Japanese Unexamined Patent Publication No. 48-60753 includes the aforementioned Unexamined Japanese Patent Application No. 48-60753.
By using a coagulation regeneration bath with a higher acid concentration and mirabilite concentration than the method disclosed in Japanese Patent No. 21738, 16-
A method of making 170 mesh porous regenerated cellulose particles is disclosed.

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

JP-A-57-212,231 discloses a method for producing cellulose powder from fibrous natural cellulose in the same manner as above.

Japanese Patent Publication No. 57-45,254 and corresponding U.S. Pat. No. 4,055,510 disclose that a suspension of viscose in a water-immiscible liquid such as chlorobenzene is heated at a temperature of 30 to 100° C. with continuous stirring. By heating to solidify and then acid decomposing the generated particles, the particle size is reduced to 150-3.
Particles in which 50 μm particles account for 85% by volume (Example 1)
It is disclosed that this can be obtained.

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 .mu.m 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-56-24429 and corresponding US Pat. No. 4.314980 and European Patent Publication No. 25
, No. 639 discloses that a solution of cellulose triacetate in a mixed solvent of a chlorinated hydrocarbon having a lower boiling point than the aqueous medium and an aliphatic higher alcohol having 6 or more carbon atoms is suspended in the aqueous medium. to form droplets of the solution, then evaporate and remove the chlorinated hydrocarbons in the droplets, and saponify the obtained spherical particles of cellulose triacetate containing an aliphatic higher alcohol to extract the aliphatic higher alcohol from the spherical particles. Disclosed is a method for producing porous cellulose spherical particles by removing. The examples disclose particles with a particle size of 100-200 μm.

JP-A No. 56-24430 discloses that triacetate of crystalline cellulose having a constant degree of polymerization is dissolved in a chlorinated hydrocarbon whose boiling point is lower than that of the aqueous medium A described later, and this solution is dissolved in A'vC suspension in the aqueous medium. A method for producing porous cellulose spherical particles, which comprises making the solution cloudy to form droplets, then evaporating and removing the chlorinated hydrocarbons in the droplets, and saponifying the obtained spherical particles of cellulose triacetate. is listed. Examples of the publication disclose porous cellulose spherical particles having a particle size of 100 to 200 μm. Japanese Unexamined Patent Publication 1987-
Publication No. 38801 and corresponding European Patent Publication No. 47,
No. 064 and U.S. Pat. Nos. 4,390.691 and 446.189 disclose that a cellulose organic acid ester solution dissolved in a solvent mainly composed of chlorinated hydrocarbons is suspended in an aqueous medium. to form droplets of the solution, evaporate the chlorinated hydrocarbon solvent in the droplets to form cellulose organic acid ester spherical particles, and then saponify the same to form porous spherical cellulose particles. A method for producing porous spherical cellulose particles is described, which comprises adding and mixing an acid or alkali to the cellulose organic acid ester solution before suspending it in an aqueous medium. There is. Examples of the same bulletin include:
Particle size is 50-100μm, exclusion limit molecular weight is approximately 2000
porous spherical cellulose particles are described. However, the products produced by this method have the drawbacks of poor pressure resistance at high speeds and poor fractionation performance as described below, and cannot be titrated for use on an industrial scale.

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 dispersion droplets of cellulose. A method is disclosed for producing granular cellulose gel by gelation agglomeration and optional regeneration with hot water.

・Unexamined Japanese Patent Publication No. 57-159802 discloses that granular cellulose is immersed in a DMSO solution of paraformaldehyde,
A method of manufacturing porous cellulose by heating and swelling is disclosed.

JP-A No. 57-219,333 discloses that an aqueous medium 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, 2ooorpm or more, and 1. A method for producing spherical microparticles of cellulose acetate by stirring and mixing for at least 10 seconds and evaporating the organic solvent is disclosed.

JP-A-48-30.752 discloses a method for producing cellulose powder by treating cellulose with tetrahydrofuran and then pulverizing the cellulose.

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

[Problem that the invention seeks to solve]

An object of the present invention is to provide microcellulose particles that are substantially composed of regenerated cellulose or type 1 cellulose and have an exclusion limit molecular weight of 3,000 or less with polyethylene glycol. Another object of the present invention is to provide microcellulose particles useful as a packing material for liquid chromatography used in so-called desalting, which separates proteins from salts such as common salt, ammonium sulfate, ammonium chloride, calcium chloride, and sodium swimming sulfate. It's about doing.

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.

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 achieved by: (a) consisting essentially of 'J-type cellulose;
The degree of agglomeration as determined by X-ray diffraction is in the range of 5 to 35%, (c) it consists essentially of spherical or long spheroidal particles with an average particle size of 300 μm or less, and (d) it is made of polyethylene glycol. This is achieved by using micro cellulose particles characterized by an exclusion limit molecular weight of 3.000 or less.

According to the present invention, the micro cellulose particles of the present invention have the following composition: α) Cellulose component: 10-60% by weight (in terms of cellulose) Water: 90-35% by weight, and a water-soluble polymer compound: 0-5% by weight removing a portion of the water from the coagulated viscose microparticles, then (2) neutralizing the resulting dehydrated coagulated viscose microparticles with acid to convert the viscose to cellulose, and optionally (3) above When removing water in step (1), the above step (2)
During or after the neutralization, the water-soluble polymer compound is removed from the fine particles generated in each step, and if necessary, (4) the fine particles obtained in step (2) or (3) above are separated from the mother liquor. Then, if necessary, desulfurization, pickling,
It can be produced by a method for producing micro cellulose particles characterized by washing with water or drying.

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 primarily consist essentially of type I cellulose, that is, regenerated cellulose.

Therefore, cellulose fine particles made of natural cellulose, ie, type I cellulose, are completely different from the fine particles of the present invention. Type I cellulose and type 1 cellulose are distinguished by well-known X-ray diffraction.

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

Second, the micro cellulose particles of the present invention are characterized by a degree of crystallinity determined by X-ray diffraction, which is 5-35%.
It has a crystallinity of . The micro cellulose particles of the present invention preferably have a content of 7 to 33%, more preferably 10 to 30%
% 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 3
It consists essentially of spherical or long spherical particles with a diameter of 00 μm or less. The micro cellulose particles of the present invention are composed of such micro particles. The micro cellulose particles of the present invention are
Further, it is substantially composed of spherical or oblong spheroidal particles having an average particle size of 1 to 200 .mu.m, preferably 2 to 150 .mu.m. As used herein, the term "0-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 oval shape. As mentioned above, microcellulose particles are spherical or oblate, and are therefore different from particles that are angular or irregularly shaped.

Fourthly, the microcellulose particles of the present invention need to have an exclusion limit molecular weight of 3000 or less with polyethylene glycol. The exclusion limit molecular weight can be determined by filling a column with water-swollen microcellulose particles and then using standard polyethylene glycol of known molecular weight. When the exclusion limit molecular weight exceeds 3,000, the separation performance between salts and compounds with molecules of 33,000 or less is reduced. In order to separate compounds with lower molecular weights with good performance, the exclusion limit molecular weight is preferably 2,500 or less, more preferably 2,000 or less, and particularly preferably 150.
It is less than or equal to 0.

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
Generally, those exhibiting a degree of polymerization in the range of 100 to 700 are preferred. If the degree of polymerization is less than 100, the pressure resistance will decrease, while if it exceeds 700, the fine cellulose particles will tend to deform, making it difficult to obtain uniform particles.

The microcellulose particles of the present invention are defined by the following formula: VD is the elution capacity (co) of blue-dextran (molecular weight 2 million), and Vll is the elution volume i (,/) of ethylene glycol. Those having a fractionation index (F) of at least 0.6 are preferred. In order to effectively separate a high molecular compound such as a protein from a salt, it is preferable that the fractionation index is as large as possible. The fractional index is preferably at least 0.8 and according to the invention even 11? A preferable fractionation index of 1.0 or more can be obtained.

Furthermore, the microcellulose particles of the invention preferably have a fractionation index of at most 2, more preferably at most 1.5.

Further, it is preferable that the micro cellulose particles of the present invention have a wet pressure resistance of at least 5 Y/an when packed in a column. In order to process quickly and in a short time, the higher the pressure resistance when wet, the more useful and preferable.

Preferably at least 10 kg/y! Deaυ,
According to the present invention, it is possible to produce a more preferable 40 kl/an" or more, or 80 to 9/cML! or more. When packed in the same column, the smaller the particle size of the cellulose fine particles, the lower the column pressure. Since the cellulose fine particles of the present invention with a particle size of 10 μm can withstand a column pressure of 80 kg, there is a great advantage that particles of various sizes can be selected according to the desired separation accuracy and throughput.

Furthermore, the micro cellulose particles of the present invention have a copper value of 3 or less, contain less carboxyl groups, and have the advantage of less adsorption due to ionicity.

The method for producing micro cellulose particles of the present invention will be explained below. According to the method of the present invention, as described above, in the first step, a part of the water is removed from the coagulated viscose fine particles containing the water-soluble polymer compound, and in the second step, the water is dehydrated. The coagulated viscose fine particles are neutralized with acid to convert the viscose into cellulose, and the water-soluble polymer compound is removed from the fine particles in a third step. The coagulated viscose fine particles containing a water-soluble polymer compound to be used in the first step are prepared by first preparing an alkaline polymer aqueous solution of (A) cellulose xanthate and a first water-soluble polymer compound other than the cellulose xanthate. (B) mixing the aqueous alkaline polymer solution and a second water-soluble anionic polymer compound to produce a fine particle dispersion of the aqueous alkaline polymer solution; (c) heating the dispersion; or It can be produced by mixing the dispersion with a cellulose xanthate coagulant to coagulate the cellulose xanthate in the dispersion as fine particles containing the first water-soluble polymer compound.

Further, the coagulated viscose fine particles containing a water-soluble polymer compound used in the first step of the present invention are secondly treated with an alkaline polymer aqueous solution of (A) cellulose xanthate and the first water-soluble polymer compound other than the cellulose xanthate. (B) The above alkaline polymer aqueous solution and number average molecular weight 1.
500 or more water-soluble polyethylene glycols or polyethylene glycol derivatives are mixed to produce a fine particle dispersion of the alkaline polymer aqueous solution at a temperature of 55° C. or more; Cellulose xanthate in the dispersion is further heated at a temperature equal to or higher than that of the cellulose xanthate containing the first water-soluble polymer compound, or by mixing the dispersion with a coagulant for cellulose xanthate. It can be produced by coagulating it into fine particles.

As described above, the first method and the second method include the step (A) of preparing an alkaline polymer aqueous solution of cellulose xanthate and a first water-soluble polymer compound, and a fine particle dispersion of an alkaline polymer aqueous solution. υ
, basically consist of the same process.

The first method and the second method are different in that the second polymer compound used in the above step (B) is anionic in the first method, but nonionic in the second method. do. First, a first method for producing coagulated viscose fine particles used in the present invention will be described below.

According to the first method, as described above, an aqueous alkaline polymer solution of cellulose xanthate and a first water-soluble polymer compound other than cellulose xanthate is prepared in step A, and fine particles of the aqueous alkaline polymer solution are dispersed in step B. A liquid is generated, and in step C, fine particles containing the first water-soluble polymer compound are generated. Step A of preparing an alkaline polymer aqueous solution of cellulose xanthate and a first water-soluble polymer compound other than cellulose xanthate is to simultaneously dissolve cellulose xanthate and a first water-soluble polymer compound other than cellulose xanthate in water or an alkaline aqueous solution. Alternatively, cellulose xanthate is first dissolved in water or an alkaline aqueous solution, and the first water-soluble polymer compound is dissolved in the obtained viscose, or the first water-soluble polymer compound is dissolved in water or an alkali aqueous solution. This can be carried out by dissolving cellulose xanthate in an aqueous solution and then dissolving the cellulose xanthate in the solution.

The above-mentioned dissolution can be carried out, for example, by mixing using a kneader or a high-viscosity stirring blade.

Cellulose xanthate may be obtained as an intermediate in the rayon manufacturing process or cellophane manufacturing process, and for example, cellulose concentration is 33% by weight and alkali concentration is 16% by weight.
And cellulose xanthate with a monovalent value of about 40 is suitable.

As the first water-soluble polymer compound, for example, a nonionic or anionic polymer compound is preferably used. Examples of the nonionic first water-soluble polymer compound include polyethylene glycol, polyethylene glycol derivatives, and polyvinylpyrrolidone. These polymer compounds have, for example, a number average molecular weight of 400 or more, and preferably have a number average molecular weight of 600 to 400,000.

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/ represents the same or different polyethylene oxide blocks, and B represents a polypropylene oxide block) is preferably used. More specifically,
For example, polyethylene glycol monomethyl ether, polyethylene glycol monolauryl ether, polyethylene glycol monocetylethyl: polyethylene glycol monomethyl phenyl ether, polyethylene dalyfur monononyl ether; polyethylene glycol monoacetate, polyethylene glycol monolaurate; and polyoxyethylene block -Polyoxypropylene block-polyoxyethylene block, etc. can be mentioned.

The anionic first water-soluble polymer compound preferably has, for example, a sulfonic acid group, a phosphonic 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 first water-soluble polymer compound having a sulfonic acid group as an anionic group has a sulfonic acid group such as vinyl sulfonic acid, styrene sulfonic acid, methylstyrene sulfonic acid,
It can be derived from monomers such as allylsulfonic acid, methallylsulfonic acid, acrylamide metalpropanesulfonic acid or salts thereof.

Similarly, the first water-soluble polymer compound having a phosphonic acid group as an anionic group can be derived from monomers such as styrene phosphonic acid, vinyl phosphonic 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, the first water-soluble polymer compound having a carboxylic acid group can be prepared by polymerizing sodium acrylate alone or by mixing it with other copolymerizable monomers such as methyl acrylate according to a method known per se. It is supplied as a homopolymer or copolymer containing polymerized units of sodium acrylate. 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 sulfonic acid group and the carboxylic acid group are respectively derived from the above monomers.

The first water-soluble anionic polymer compound preferably contains at least 20 mol % of polymerized units of the above-mentioned monomers having anionic groups. Such preferred polymeric compounds include copolymers and homopolymers.

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

The water-soluble first anionic polymer compound used in step A is not limited to the vinyl type polymers mentioned above,
Other examples include carboxymethyl cellulose, sulfoethyl cellulose, and salts thereof such as Na salts.

According to the first method, as described above, first, in step A, an alkaline polymer aqueous solution is prepared. The aqueous core polymer solution preferably has a cellulose concentration derived from cellulose xanthate of 3 to 15% by weight, more preferably 5 to 12% by weight.
The alkaline concentration is preferably adjusted to 2 to 1.
It is adjusted to 5% by weight, more preferably 5 to 10% by weight. Further, the amount of the first water-soluble polymer compound is preferably adjusted to 0.03 to 5 parts by weight per 1 part by weight of cellulose.

According to the first method, the alkaline polymer aqueous solution prepared in step A is then mixed with a second water-soluble anionic polymer compound in step B.

For mixing, any means capable of producing a fine particle dispersion of an aqueous alkaline polymer solution can be used. 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 second water-soluble anionic polymer compound is preferably used as an aqueous solution, more preferably at a concentration of 0.5 to 25% by weight, particularly preferably 2 to 222% by weight.
It is used as a t% aqueous solution. Such an aqueous solution preferably has a viscosity of 3 centipoise to 50,000 centiboise, particularly 5 centipoise to 30,000 centiboise, at 20°C.

The alkaline polymer aqueous solution and the second water-soluble anionic polymer compound are 0.3 to 100 parts by weight, preferably 1 part by weight of the second polymer compound per 1x part of cellulose in the alkaline polymer aqueous solution. ~45 parts by weight, particularly preferably 4 to 20 parts by weight, are used and mixed. The mixing is advantageously carried out at a temperature lower than the boiling point of carbon disulfide contained in the aqueous alkaline polymer solution, preferably in the range of 0 to 40°C.

According to the research of the present inventor, when an acid-decomposable inorganic salt such as calcium carbonate is present as a dispersant in the alkaline polymer aqueous solution in Step A, for example, in an amount of 0.5 to 5 times It has become clear that the morphology of the fine particles in the fine particle dispersion produced in the second step is maintained stably and well.

Examples of the second water-soluble anionic polymer compound include the same compounds as the above-mentioned examples of the anionic first water-soluble polymer compound.

The second water-soluble anionic polymer compound may be the same as or different from the first water-soluble polymer compound.

According to the present method for producing coagulated fine particles, the fine particle dispersion of the aqueous alkaline polymer solution produced in step B is then coagulated in step C.

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

Solidification by heating can be advantageously carried out at a temperature higher than the boiling point of carbon disulfide contained in the aqueous alkaline polymer solution, 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, and combinations thereof with the third water-soluble polymer compound are preferably used. The lower aliphatic alcohol may be linear or branched, and examples thereof include aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol, 1so-propanol, n-propanol, and n-butanol. Preferably used. Examples of alkali metal salts of inorganic acids include NaCl, Na, and S.
o, Na salts such as , salts such as K2SO4 are preferable,
Preferable examples of the alkaline earth metal salt include Mg salts such as Mg5O, and Ca salts such as CaC1.

As the third water-soluble polymer compound, for example, nonionic and anionic polymer compounds are preferably used. It is particularly desirable to use the same third water-soluble polymer compound as the second anionic polymer compound used in step B.

Examples of the third water-soluble polymer compound will be understood from the above-mentioned examples of the first water-soluble polymer compound.

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.

Next, a second method for producing coagulated viscose fine particles used in the present invention will be explained.

According to the second method, an alkaline polymer aqueous solution of cellulose xanthate and a first water-soluble polymer compound other than the cellulose xanthate is prepared in step A, and the alkaline polymer is prepared in step B. A microparticle dispersion in an aqueous solution is produced, and in step C, microparticles containing cellulose are produced. In this respect, it is basically the same as the first manufacturing method described above. Step A of preparing an alkaline polymer aqueous solution of cellulose xanthate and a first water-soluble polymer compound other than cellulose xanthate is carried out in the same manner as the method described in the description of the first manufacturing method above. For example, the xanthate and other first water-soluble polymer compounds used are the same as those described in the first production method.

Step B of producing a fine particle dispersion of an alkaline polymer aqueous solution includes an alkaline polymer aqueous solution and a number average molecule of -[150
This is carried out by mixing zero or more water-soluble polyethylene glycols or polyethylene glycol derivatives.

The high molecular weight polyethylene glycol or polyethylene glycol derivative used has a number average molecular weight of 91.500 or more, preferably 1.50.
It has a number average molecular weight of 0 to 400,000.

As a polyethylene glycol derivative, for example, only the hydroxyl group at one end of polyethylene glycol has 1 to 1 carbon atoms.
18 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' is the same or different, represents a polyethylene 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 monocetylethyl; polyethylene glycol 7-methyl phenyl ether, polyethylene glycol monononylphenyl ether; polyethylene glycol monoacetate, polyethylene glycol monolaurate;
and polyoxyethylene block-polyoxypropylene block-polyoxyethylene block.

Among polyethylene glycol and its derivatives, polyethylene glycol is more preferred, and has a number average molecular weight of 6,
A number average molecular weight of s, ooo to 100,000 is particularly preferred, with a number average molecular weight of iio, oo.

30,000 is particularly preferred. The polyethylene glycol derivative preferably has a molecular weight of 1,500 to 16,000
It has a number average molecular weight of

According to the second method, in step B, an alkaline aqueous polymer solution and a water-soluble high molecular weight polyethylene glycol or a derivative thereof are first mixed. For mixing, any means capable of producing a fine particle dispersion of an alkaline aqueous polymer solution can be used. The specific means are as described in the description of the first manufacturing method above.

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 from 0.5 to
60% by weight, particularly preferably 5-55% by weight 10
It is used as a ~40% by weight aqueous solution.

The alkaline polymer aqueous solution and polyethylene glycol or polyethylene glycol derivative are 1 to 30 parts by weight of polyethylene glycol or polyethylene glycol derivative per 1 part by weight of cellulose, more preferably 1-12 to 2 parts by weight.
8 parts by weight, particularly preferably 4 to 24 parts by weight, especially 8 to 1 part by weight
6 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 the aqueous alkaline polymer solution is produced. The fine particle dispersion of the aqueous alkaline polymer solution is produced at a temperature of 55°C or higher. 55℃
At lower temperatures, it is not possible to obtain a fine particle dispersion of the basic aqueous alkaline polymer solution capable of providing the desired fine cellulose particles.

According to the second method, the fine particle dispersion of the aqueous alkaline polymer solution produced in step B is then solidified in step C.

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 preferably 6
It is carried out at temperatures between 0°C and 90°C.

The coagulant and its usage ratio are the same as described in the explanation of the fourth manufacturing method above.

When using a combination of polyethylene glycol or its derivatives as the above-mentioned coagulant, the addition of the coagulant can prevent the concentration of polyethylene glycol or its derivatives from decreasing in the system. This method has the advantage of stably coagulating the liquid.

According to the method of the present invention, in the first step, a portion of the water is removed from the coagulated bistooth fine particles having the above composition.

The coagulated viscose fine particles obtained by the first method and the second method as described above consist essentially of spherical or long spherical particles with an average particle diameter of 400 μm, and the cellulose component 1
It has a weight composition of 0 to 60% by weight (in terms of cellulose), 90 to 35% by weight of water, and O to 5 water-soluble polymer compounds.

The component composition of the coagulated viscose fine particles referred to here is determined by washing and replacing water and water-soluble polymer compounds adhering to the surface of the fine particles with excess hexane, and drying at 50°C for 60 minutes. After removing hexane, the microparticles were
Dry at 5°C for 3 hours to determine the cellulose component. In addition, if a water-soluble polymer compound is contained, the contained polymer compound is removed by washing with water in advance when determining the cellulose component.

The coagulated viscose fine particles used in the first step are those with water or a water-soluble polymer compound attached to the particle surface, or are washed with n-hexane to remove the water or water-soluble polymer compound on the particle surface. It has been removed. For example, a concentrated aqueous solution of an inorganic salt or a hydrophilic medium is used to remove water from the coagulated viscose fine particles.

As the concentrated aqueous solution of the inorganic salt, preferably a saturated or supersaturated aqueous solution is used. Inorganic salts include sodium sulfate, ammonium sulfate, calcium chloride, and the like.

Examples of the hydrophilic medium include butanol and isobutyl alcohol as aliphatic alcohols, ethylene glycol and glycerin as polyhydric alcohols, diethyl ketone as ketones, and dimethylformamide and acetamide as acid amides.

Water removal is preferably carried out at a temperature of 30 to 90°C, more preferably 50 to 80°C. The slower the water removal, the better, and the temperature is selected appropriately depending on the amount of water in the coagulated viscose particles used, but the temperature is 90°C.
If carried out at a temperature higher than that, the removal of water will be rapid, which is undesirable.

According to the present invention, the coagulated viscose fine particles from which part of the water has been removed in the first step are then neutralized with an acid in the second step to convert the viscose into cellulose.

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;
Convert to cellulose.

Although the water-soluble polymer compound is removed during the water removal or neutralization, the water-soluble polymer compound can also be removed by further treatment in the third step. Removal of the water-soluble polymer compound is carried out, for example, by washing with water or methanol. In order to completely remove it,
It is preferable to carry out a combination of hot water washing and methanol washing.

Next, in the fifth step, the cellulose fine particles are separated from the mother liquor, and are desulfurized, pickled, washed with water, or dried as necessary.

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.

(Effects of the Invention) As described above, the micro cellulose particles of the present invention are substantially composed of type 1 cellulose, and have a crystallinity in the range of 5 to 35% as determined by X-ray diffraction. Particle size is 300μ
It consists essentially of spherical or long spherical particles of less than m, and the exclusion limit molecular weight for polyethylene glycol is a.
, ooo or less, it is relatively stable against chemicals and has no toxicity, so it can be suitably used as a packing material for liquid chromatography, for example.

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

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

Method for Measuring Crystallinity> It is determined by the method for measuring the crystallinity of cellulose using the Xlfs diffraction method described in the Journal of the Japan Institute of Textile Science and Technology, Vol. 19, A2 (1963), pages 113 to 119. That is, the X-ray diffraction curve with 2θ from 5° to 45° is calculated using the following equation.

Crystallinity (x) - x 1o.

T/ Here, T' snow ((a+C) - b) x KK = 0.89
6 (Incoherent scattering correction coefficient of cellulose) C=c-a a: Diffraction curve of non-grade starch (2θ=5 to 45°)
area, b: area of air scattering curve (2θ = 5 to 45°), C:
Area of diffraction curve (2θ=5 to 45°) of sample, <Average degree of polymerization> It was determined according to the method described in JIS L-1015.

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

<Average Particle Size Measuring Method> Approximately 0.1 f of a sample is taken, poured into 25 m/25 m of pure water, stirred and dispersed, and measured using a light transmission particle size distribution analyzer.

Example 1 500f of pulp made of coniferous wood was immersed in a 18% by weight caustic soda solution 201 at 20° C. for 1 hour and compressed to a size of 28 times. Pulverize for 1 hour while raising the temperature from 25°C to 50°C,
After aging, carbon ditheride (164 M') of 33% by weight relative to cellulose was added and sulfurized at 25° C. for 1 hour to obtain cellulose xanthate. The xanthate was dissolved in an aqueous solution of caustic soda to obtain viscose. The viscose has a cellulose concentration of 9.3 weight 9 (and a caustic soda concentration of 5.9
% by weight, and the viscosity was 6,200 centipoise.

500 mt of the above-prepared viscose 601 and an aqueous solution of sodium polyacrylate (polymer immersion degree 12 weight 9K, molecular weight 50,000) 2402 as an anionic polymer compound! 7
The total amount was 3009. At a liquid temperature of 30°C, use a laboratory stirrer (Yamato Scientific Co., Ltd.: A: MODgL).
LR-51B, rotating blade 7-) After stirring at 600 rpm for 10 minutes to generate fine viscose particles, the liquid temperature was lowered from 30°C to 70°C while stirring continuously.
The temperature was raised to 70° C. over 15 minutes and maintained at 70° C. for 10 minutes to solidify the viscose fine particles. The coagulated viscose particles were separated from the mother liquor by a centrifugal dewatering filter (3000G). The obtained coagulated viscose particles had a particle size of 80 μm and contained 45% by weight of cellulose component (in terms of cellulose) and 55% by weight of water.
Met.

Next, the coagulated viscose particles were dehydrated in a saturated sodium sulfate solution at 80° C. for 60 minutes. The resulting dehydrated and coagulated viscose particles contained 60% by weight of cellulose component (in terms of cellulose) and 40% by weight of water. Next, the dehydrated and coagulated viscose fine particles were neutralized and regenerated with 100 y/l sulfuric acid to convert viscose into cellulose.

Subsequently, after separating cellulose fine particles from the mother liquor through an IG4 type glass filter, desulfurizing the 22/L with 2 tons of caustic soda aqueous solution at 50°C, neutralizing with 22/L of sulfuric acid aqueous solution, and washing with a large excess of water. The mixture was dried at 105° C. for 5 hours to obtain fine cellulose particles. Table 1 shows the properties of the obtained microcellulose particles.

Table 1 Example 2 Coagulated viscose particles obtained in Example 1 (particle size 80 μm
1 Cellulose ingredient 45% by weight, 50% by weight of water;
Dehydration treatment was performed in a saturated ammonium chloride solution for 60 minutes at 0°C. The obtained dehydrated and coagulated viscose particles contained 55% by weight of cellulose component and 45% by weight of water.

Next, fine cellulose particles were obtained in the same manner as in Example 1. The properties of the obtained micro cellulose particles are shown in Table 2.

Table 2 Example 3 Coagulated viscose particles obtained in Example 1 (#!, diameter 80
μ, cellulose component 45% by weight, water 55% by weight) at 80%
Dehydration treatment was carried out in ethylene glycol for 60 minutes at °C. The resulting dehydrated and coagulated viscose particles contained 61% by weight of cellulose and 49% by weight of water. Next, fine cellulose particles were obtained in the same manner as in Example 1. Table 3 shows the properties of the obtained microcellulose particles.

Table 3 Example 4 After dissolving the xanthate obtained in Example 1 in a caustic soda aqueous solution, polyethylene glycol (molecular weight 6000)
50F was added and dissolved to prepare an aqueous alkaline polymer solution of cellulose xanthate and polyethylene glycol. The alkaline polymer aqueous solution has a cellulose concentration of 9.
3% by weight, caustic soda concentration 6.1% by weight, polyethylene glycol 0.9% by weight, and viscosity 7400 centiboise.

60F of the above-prepared alkaline polymer aqueous solution and 240F of an aqueous solution of sodium polyacrylate (polymer concentration 12% by weight, molecular weight 50,000) as an anionic polymer compound.
The total amount was 3002. Viscose fine particles containing polyethylene glycol were coagulated in the same manner as in Example 1. The coagulated viscose particles were separated from the mother liquor by a centrifugal dehydrator (3000G). The obtained coagulated viscose particles had a particle size of 85 μm,
The cellulose component was 45% by weight, water was 53% by weight, and polyethylene glycol double layer% was contained.

The coagulated viscose particles were then dehydrated in a saturated sodium sulfate solution at 80° C. for 60 minutes.

The obtained dehydrated and coagulated viscose particles contained 60% by weight of cellulose component, 39% by weight of water, and 1liit% of polyethylene glycol.

Next, the viscose particles containing the dehydrated and coagulated polyethylene glycol were neutralized and regenerated with 100 y/l sulfuric acid to convert the viscose into cellulose. After separating the cellulose particles containing polyethylene glycol from the mother liquor, the cells were heated at 50°C for 2? /2 tons of caustic soda aqueous solution
After desulfurization with water and neutralization with a 2 f/l aqueous sulfuric acid solution, polyethylene glycol was removed from the fine particles by washing with a large excess of water and drying at 105° C. for 5 hours to obtain fine cellulose particles.

Table 4 shows the properties of the obtained microcellulose particles.

Table 4 Example 5 In Example 4, polyethylene glycol (molecule!6
,000), sodium polystyrene sulfonate (
Table 5 shows the characteristics of microcellulose particles obtained in the same manner as in Example 4, except that particles with a molecular weight of 10,000 were used.

Table 5 Example 6 Viscose 30F obtained in Example 1 and an aqueous solution of sodium polystyrene sulfonate (polymer concentration 14% by weight, molecular weight 500,000) 270F as an anionic polymer compound were placed in a 500 Go flask, and the total amount was set to 3001. Stirring with a laboratory stirrer at 11,000 rP for 10 minutes at a liquid temperature of 30°C was performed to generate fine viscose particles, and then the liquid temperature was increased from 30°C to 70°C while continuing to stir.
℃ in 15 minutes, maintained at 70℃ for 10 minutes,
The viscose fine particles were solidified. The obtained coagulated viscose particles had a particle size of 20 μm and a cellulose component of 50% by weight (cellulose was replaced by water).

% by weight.

Table 6 below shows the properties of the micro cellulose particles obtained in the same manner as in Example 1.

Table 6 Example 7 The micro cellulose particles of Examples 1 to 6 were used in Q and φ, respectively.
A stainless steel column of X25 crn was filled with water as a filling liquid at a flow rate of Z Oml/min over 30 minutes. Next, using each packed column as a separation column, the relationship between elution time and molecular weight was investigated using standard polyethylene glycol with a known molecular weight under the following analysis conditions. The results are shown in Table 7.

Analysis conditions 1, pump HLC-03D manufactured by Toyo Soda Kogyo Co., Ltd. 2 eluent pure water 3, flow rate 1.0 g/min 4, temperature room temperature 5, detector RI detector Table 7 Among these, examples include: FIG. 1 shows the relationship between the molecular weight of polyethylene glycol and the elution time for RunAl and A4 microcellulose particles.

The fine sesame particles of Example 1 (Run7@1: 66 μm) and Example 6 (Runi6: 12 μm) were each packed into a stainless steel column of φ×250 for 8 mornings.
Using pure water as the eluent, we investigated the relationship between flow rate and column pressure. As shown in Figure 2, particle size 12 μmoRu
It is understood that the n-6 particles can be pressurized up to 80 kli/am" and can be used at high flow rates.

[Brief explanation of the drawing]

FIG. 1 shows the micro cellulose particles of the present invention (Example 1: R
FIG. 4 is a diagram showing the relationship between molecular weight and elution time showing the separation performance of unAl (obtained in Example 4: Run J 4) as a packing material for liquid chromatography. FIG. 2 shows the micro cellulose particles of the present invention (Example 1: R
FIG. 2 is a diagram showing the relationship between column pressure and flow rate showing the pressure resistance performance of unn1, Example 4: RunAlt' obtained as a packing material for liquid chromatography. 1 other person

Claims (1)

[Scope of Claims] 1. (a) consisting essentially of cellulose type 11; (b)
The degree of crystallinity determined by X-ray diffraction is in the range of 5 to 35%, (c) it consists essentially of spherical or oblate particles with an average particle size of 300 μm or less, and (d) it is excluded by polyethylene glycol. Microcellulose particles having a limiting molecular weight of 3,000 or less. 2. Micro cellulose particles according to claim 1, having a crystallinity in the range of 7 to 33%. 3. Micro cellulose particles according to claim 1, having a crystallinity in the range of 10 to 30%. 4. The micro cellulose particles according to claim 1, which consist essentially of spherical or oblong spherical particles having an average particle diameter of 1 to 200 μm. 5. The micro cellulose particles according to claim 1, which essentially consist of spherical or oblong spherical particles having an average particle diameter of 2 to 150 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 an exclusion limit molecular weight of 2,500 or less. 8. Micro cellulose particles according to claim 1, which have an exclusion limit molecular weight of 2,000 or less. 9. Micro cellulose particles according to claim 1, wherein the degree of polymerization of cellulose is in the range of 100 to 700. 10. The following formula F=(V_E-V_D)/V_D where V_D is the elution volume (ml) of blue-dextran (molecular weight 2 million), and V_E is the elution volume (ml) of ethylene glycol. Microcellulose particles according to claim 1, having a defined fractionation index (F) of at least 0.6. 11. Micro cellulose particles according to claim 1, which have a fractionation index (F) of at least 0.8. 12. The micro cellulose particles according to claim 1, having a fractionation index (F) of at most 2. 13. The micro cellulose particles according to claim 1, which have a pressure resistance when wet of at least 5 kg/cm^2. 14. The micro cellulose particles according to claim 1, which have a pressure resistance when wet of at least 10 kg/cm^2. 15. The micro cellulose particles according to claim 1, wherein the cellulose has a copper value of 3 or less. 16, (1) The following composition: Part of the water is removed from coagulated viscose fine particles having 10 to 60% by weight of cellulose component (in terms of cellulose), 90 to 35% by weight of water, and 0 to 5% by weight of a water-soluble polymer compound. and then (2) neutralizing the resulting dehydrated coagulated viscose microparticles with acid to convert viscose into cellulose, and optionally (3) during the water removal in step (1) above. Above process (2)
During or after the neutralization, the water-soluble polymer compound is removed from the fine particles generated in each step, and if necessary, (4) the fine particles obtained in step (2) or (3) above are separated from the mother liquor. Then, if necessary, desulfurization, pickling,
A method for producing micro cellulose particles characterized by washing with water or drying. 17. The method according to claim 16, wherein the coagulated viscose fine particles used in step (1) have an average particle size of 400 μm or less. 18. The method according to claim 16, wherein the water removal in step (1) is carried out by contacting the coagulated viscose microparticles with a concentrated aqueous solution of an inorganic salt. 19. The method according to claim 18, wherein the concentrated aqueous solution of the inorganic salt is a saturated or supersaturated aqueous solution of the inorganic salt. 20. The method according to claim 16, wherein the water removal in step (1) is carried out by bringing the coagulated viscose fine particles into contact with a hydrophilic medium. 21. The method according to claim 16, wherein the hydrophilic medium is an aliphatic alcohol, a polyhydric alcohol, a ketone, or an acid amide. 22. The method according to claim 16, wherein the water removal in step (1) is carried out at a temperature in the range of 30 to 90°C. 23. The method according to claim 16, wherein the acid used for neutralization in step (2) is a strong inorganic acid. 24. The method according to claim 23, wherein the inorganic strong acid is hydrochloric acid or sulfuric acid.