CS210703B3 - Manufacturing process of spherical cellulose particles - Google Patents

Description

(54) A method for producing spherical cellulose particles

The invention relates to a process for producing spherical cellulose particles.

The present invention is dependent on the process for preparing pearl cellulose according to U.S. Pat. No. 172,640, which consists in preparing pearl cellulose by heating a suspension of viscose in water-immiscible liquids to an elevated temperature of 30 to 100 ° C.

Under these conditions, a sol-gel transition occurs and the original liquid viscose in the dispersion turns into a gel product composed of spherical particles. According to the other procedures described in the said certificate, the regeneration of the cellulose can be continued without undesirable deformation of the spherical shape of the individual particles. According to MS. No. 210,701, the regeneration of cellulose is preferably carried out by hydrolytic decomposition of xanthogenate groups.

Procedure according to MS. No. 172,640 convincingly demonstrates the usefulness of the new process for preparing bead cellulose based on solidification of the dispersion under stationary hydrodynamic conditions, thermally induced by sol-gel transition, but does not pay particular attention to the important stage of bead cellulose preparation, which is solidified.

The process for preparing the spherical cellulose particles according to U.S. Pat. Certificate No.

No. 172,640 resembles the preparation of bead polymers by suspension polymerization, particularly as regards dispersion formation prior to solidification. However, dispersion of viscose in organic solvents requires special conditions and unusual compositions of the dispersion system.

While suspension polymerization is based on low viscosity monomeric liquids of the order of 10 ⁴ Ns / m ² , readily dispersible in the environment, aqueous spherical cellulose xanthate solutions, i.e. strongly viscous polyelectrolyte solutions having a viscosity in Ns / units, should be dispersed m ² .

For monomer mixtures, the dispersed droplet size can be varied relatively easily by adjusting the stirrer speed, which is not as easy with viscose dispersion. The high viscosity of aqueous solutions of cellulose xanthate prevents the establishment of an equilibrium droplet size distribution during dispersion. While the dispersions of the monomer mixtures readily disintegrate and join in the precipitation of the individual droplets, in the case of viscose this is much slower and there is a risk that a greater number of glued, interconnected or interconnected particles may be present in the solidified suspension. non-spherical particles. If special precautions are not taken and only the general experience of suspension polymerization is applied, poor quality and / or high-quality polymerization may be obtained. to unusable pearl product.

SUMMARY OF THE INVENTION The present invention provides a process for the manufacture of spherical cellulosic particles according to the author's certificate No. 172 640, characterized in that the viscose is dispersed in an organic solvent which is chlorobenzene or a mixture of dichlorobenzene and naphtha. In the presence of anionic or nonionic surfactants with a longer aliphatic chain containing up to 18 carbon atoms, selected from the group consisting of alkali metal olefins or stearates, stearic acid or oleic acid, or an alkali metal stearate; sorbitan oleate in an amount of 0.02 to 40 g / kg viscose.

According to the present invention, when dispersing the viscose, the dispersion system is chosen to facilitate the formation of beads of the desired size and to reduce their sticking or sticking. deformation during dispersion.

In the dispersion system, the tendency to gravitationally separate the two phases counteracts the agitation, depending on the difference in the specific weights of the dispersion medium and the dispersion phase. The specific gravity of the viscose at room temperature is about 1.1 to 1.15 g / cm @ 3.

Better results are obtained if the dispersion medium corresponds to its specific viscosity. It has been found that, for example, chlorobenzene of spec. 1.11 and that it is easier to obtain satisfactory dispersions when using chlorobenzene than dichlorobenzene of 1.46 g / cm @ 2. Instead of a single solvent, mixtures of similar specific gravity to viscose can also be used, e.g. dichlorobenzene / diesel blends. .

The high viscosity of aqueous solutions of cellulose xanthogenate makes it difficult to mix in an organic solvent, and changing the stirrer speed has a relatively small effect on droplet size. It has been found that reducing the interfacial tension in the dispersion system by adding suitable surfactants is more useful than increasing the mixing intensity. Surprisingly, it has been found that the efficacy of the additives is significantly dependent on their chemical structure.

For example, alkylpciyethylene glycol ether (alkyl C1-C18, polymerization grade PEG 1- 15, with a free PES content of 25 to 28%) or nonylphenolpolyethylene glycol ether (polymer grade PEG = 5) produced by the chemical plants of W. Pieck in Nováky under Mark Slovapott N, resp. Slovafol 905.

Under the conditions in which both of the above-mentioned formulations did not occur, a significant effect was found on stearic acid, oleic acid and derivatives thereof, namely the alkali salts of both acids and oleic acid ester with sorbitan.

From these results it was possible to conclude that sodium and potassium soaps of extremely high fatty acids, which cause formation and preservation even in low concentrations, are extremely suitable.

spherical drops of viscose. It is not necessary to introduce directly into the dispersed system soaps which are poorly soluble in the dispersion medium (they only dissolve after heating, for example), but such soaps can be formed in the dispersion system only during the dispersion. Such solutions have the advantage of easier handling, more accurate dosing and controlled effect. Instead of cis-9-octadecenane, respectively. For example, alkali metal octadecanate can be used to add the corresponding acids, which in themselves are ineffective but readily dissolve in chlorobenzene and provide effective soaps with the viscous lye at the interface. Since the necessary additions of surfactants are very low, the viscose composition is not disturbed and the cellulose regeneration itself is not affected.

In addition to salts of higher fatty acids, some of its esters, such as sorbitan oleanes, are also suitable. They are well soluble in chlorobenzene even at higher concentrations and show good dispersing effect. Under elevated temperature dispersion conditions, their alkaline hydrolysis and formation of sodium cis-9-octadeeenate can be expected.

By the method of the invention, it is possible to obtain a pearl product of perfect spherical shape and a desired particle size in the range of 20 to 1000 µm.

The significant technical effect of the new invention is that it substantially facilitates the dispersion of viscose prior to solidification, allows the preparation of the bead cellulose product in a perfectly spherical shape, and extends the useful range of spherical cellulose particle sizes. The bead product prepared under the conditions of the invention is superior to the products obtained according to the processes known to date.

In the following, the invention is illustrated, but not limited, by a few exemplary embodiments,

Example 1 to 22

Viscose made of spruce kraft cellulose was used for dispersions and characterized as follows:

average polymerization degree of cellulose .AND- before sulfidation 500 - 20 May alpha-cellulose 7.1 - 0.1% total alkalinity (NaOH) 6,1 í 0.1. % total sulfur 2,3 - 0.1% viscosity 4,5 to 5, J Ns / w ²

The dispersion was carried out in a 250 ml reactor, heated from a duplicator with water, with a stainless steel anchor stirrer at 750 rpm. To the chlorobenzene (120 ml), in which the surfactant was dissolved or dissolved, viscose (ca 30 ml) was added with stirring, and its precise weighing was determined by differential weighing of the weighing vessel. The mixture was stirred at room temperature for 5 minutes, heated for 15 minutes at 90 C, ^U and maintained at this temperature for 30 minutes.

The solidified suspension was cooled with water from the duplicator to room temperature, the pearl product was aspirated on a frit and washed with excess boiling water. The shape and size of the particles were evaluated using a microscope.

Variable experimental conditions and results obtained:

Example number Post-active substance Result Chem. composition, resp. designation Dose ·, appearance vellkos | wt. % per vis. .g / m- v CB 1 --- - - non-spherical lumps 1 000 2 alkylpo.t yethylene- glycol ether (Slovapon N) 0.29 699 non-spherical block - 3 nonylfe nolpolye thylene glycol ether (Slovafol 905) 0.29 706 sleDené roughly particle 4 zinc octadecanate 0.29 683 balls and spheres. part. 100 ALIGN! to 500 5 sodium octadecanate sapo medicines. 0.29 676 marbles 50 to 400 6 potassium cis-9-octadecenate. - sapo caline 0.29 694 marbles 100 ALIGN! to 400 7 octadecanoic acid 0.26 679 marbles 50 to 400 8 cis-9-octadecenoic acid 3.10 ⁴ 0.75 ineffective. block - 9 cis-9-octadecenoic acid 14.10 ' ⁴ 3.77 pasted product - 10 cis-9-octadecenoic acid 29.10 ⁴ 7.5 marbles 430 to 1 450 11 - cis-9-octadecenoic acid 28.10 ' ³ 75.3 marbles 40 to 400 12 cis-9-octadecenoic acid 0.14 377 marbles 70 to 290 13 cis-9-octadecenoic acid 0.29 685 marbles 20 May to 200 14 cis-9-octadecenoic acid 0.60 1 506 marbles 50 to 240 15 Dec cis-9-octadecenoic acid 1.50 3 765 marbles 20 May to 140 16 sorbitan olean (SLEEP 80) 3.10 ' ³ 7.5 nespheres. block - 17 sorbitan olean (SLEEP 80) 29.10 ' ³ 75.3 nespheres. particle ca 1 500 18 sorbitan olean (SLEEP 80) 0.29 688 marbles 30 to 700 19 Dec sorbitan olean (SLEEP 80) 0.60 1 506 marbles 30 to 250 20 May sorbitan olean (SLEEP 80) 1.50 3 765 marbles 20 May to 100 ALIGN! 21 cis-9-octadecenoic acid + 3.10 ' ³ 7.53 marbles 200 to 1 250 sorbitan olean (SLEEP 80) 30.1 o ' ³ 75.3 marbles 200 to 1 250 22nd cis-9-octadecenoic acid 15.10 ' ⁴ 3.77 glued nespheres. particle - nonylphenolpolyethylene glycol ether (Slovafol 905) 400.10 ⁴ 99.0 •

Example 23 to 28

The technical viscose was used for dispersion as in the previous case, containing the following additives:

1,540 polyethylene glycol (Berol Glyco 1,540) 1.5 % high molecular weight product of hydroxyethylated fatty amines with polyalkylene oxide, (Art. No. Kordamin V) 1,2 % alkylamine polyoxyethylene glycol, No. Berol Visco 32) 0.3 56

The dispersion was carried out in a 3,000 ml reactor with an anchor stainless steel stirrer at 500 rpm. The procedure was the same as in the previous case, weighing approximately 500 g of viscose and 1500 ml of chlorobenzene.

Variable experimental conditions and results obtained:

Example Surfactant Result

number Chem. composition, resp. designation Batch. , wt. % g / m ^J per vis. v CB appearance size / um 23 nespheres. lumps 24 sorbitan olean (SLEEP 80) 1.0 2,988 marbles 27 to 380 25 cis-9-octadecene potassium. sapo kalinus' 0,1 295 marbles 42 to 310 26 potassium cis-9-octadecenate. sapo kalinus' 0,1 301 marbles 38 to 320 27 Mar: octadecanan sod. - sapo medicines. 0,1 301 marbles 46 to 254 28 octadecanan sod.-sapo 0,1 301 marbles 38 to 220 ° ° and - soap dissolved in chlorobenzene b - soap dissolved in viscose Example 1 and 29 to 32 Technical dispersion was used for dispersion viscose and reactor such as in examples 23 to 28.

Variable experimental conditions and results obtained:

Example

Dispersing environment Dose of oleansorbate (SPAN-80) wt. % per vis. Particle size pm

29 p-dichlorobenzene 0.21 . 128 to 672 30 naphtha + p-dichlorobenzene, 1: 2 0.19 73 to 388 31 naphtha + p-dichlorobenzene 1.00 10 to 155 32 . .. chlorobenzene 0.99 27 Mar: to 380

Example 33 to 39

The technical viscose, characterized as follows, was used for dispersion:

65% spruce sulphite cellulose with an average polymerization degree of ca 750 and 35% beech sulphate cellulose with a polymerization degree of ca 600 were used for the preparation of viscose.

Cellulose content in viscose 8.0 to 8.3%

NaOH content in viscosity 6.0 to 6.2%

Sulfur content in viscose 2.3 to 2.4%

Viscosity 4-5 Ns / m 2

Modified by adding an alkylpolyethylene glycol ether produced by reacting a mixture of higher fatty alcohols with ethylene oxide at a molar ratio of 1:25 to 1:20 (Slovasol 0) of 2 g / kg cells.

The same apparatus and procedure as in Examples 1 to 22 were used. The dispersion medium was chlorobenzene (120 mL) and about 30 g of viscose (dispensed by differential weighing) was dispersed.

Variable experimental conditions and results obtained:

Claims (1)

SUBJECT OF THE INVENTION The process for the production of spherical cellulose particles depends on the Czechoslovak. No. 172,640, characterized in that the viscose is dispersed in an organic solvent such as chlorobenzene or a mixture of dichlorobenzene and naphtha having a specific gravity at room temperature of between 1.0 and 1.2 g / cm < 3 > non-ionic surfactants having a longer aliphatic chain containing up to 18 carbon atoms, selected from the group consisting of alkali metal olefins or stearates, stearic or oleic acid, and the like; sorbitan olean in an amount of 0.02 to 40 g / kg viscose.