MXPA97006395A

MXPA97006395A - Particles of cellulose, method to produce them, and its

Info

Publication number: MXPA97006395A
Application number: MXPA/A/1997/006395A
Authority: MX
Inventors: Jorg Oberkofler; Thomas Moser; Anton Schmalhofer; Jeffrey F Spedding
Original assignee: Tfm Handelsaktiengesellschaft
Priority date: 1995-02-21
Filing date: 1997-08-21
Publication date: 1998-11-12

Abstract

The present invention relates to cellulose particles having cationic groups, characterized in that the cationic groups are present even inside the cellulose particles, distributed over the total cross-section of the particles, the concentration of the cationic groups being constant or increasing from the outside to the inside and being at least one cationic group present per 100 anhydroglucose units of the cell

Description

PARTICLES OF CELLULOSE - METHOD TO PRODUCE THEM, AND THEIR USE This invention relates to cellulose particles and to a method for producing them. It also deals with applications of cellulose particles. Due to different measures such as concentration of the circuit, greater use of desizing pulps, and high performance pulps, such as wood pulp and thermomechanical pulp (PTM), and neutral processing, there has been an increase in the load of interfering substances (garbage) in the water circuits of the paper industry. Interfering substances were first defined as all those substances that reduce the effectiveness of cationic retention aids in the supply of paper, ie, those substances added in order to improve the retention of the fiber / filler mixture on the wire. Recently, this definition has been asserted more precisely. Accordingly, the interfering substances are the dissolved or colloidally dissolved anionic oligomers or polymers, and the nonionic hydrocolloids. These interfering substances have different effects. They impair the action of the retention aids, of the dry and wet strength agents, that is, the substances that increase the strength of the paper, and also lead to deposits in the circuit of the paper machine, to alterations in the formation and drainage, and a loss of the resistance, the whiteness, and the opacity of the paper. In order to eliminate the adverse effects of these substances that interfere with papermaking, alum, polyaluinium chloride, low and high molecular weight fixatives, cationic starch and inorganic adsorbents are used. All these substances get to join the anionic garbage with the help of electrostatic interactions, and form complexes with it. By linking these complexes with the fibers, or through the filtering effects on the wire, these aggregates are removed from the paper machine system. However, all these products have their own drawbacks. For example, aluminum salts can only be used to a limited degree in neutral processing, which is becoming important due to the increasing use of calcium carbonate as a filler, since they are not cationically charged, and therefore, are not very effective in this pH scale. The use of highly charged cationic polyelectrolytes, in turn, involves the problem of an accurate measurement. Otherwise, an over-ionization of the paper machine circuit may occur, and therefore, a cationic dispersion. This means that there may be poor retention of fine substance and reduced sizing. Japanese Patent Number JP-A-61-258, 801 discloses cationically regenerated cellulose, wherein the cationicity serves to increase the receptivity of dye by the fibers. The process described therein uses a low concentration of cationizing agent in order to keep the number of cationic groups within limits, because this would lead to a loss of fiber strength. R.A. Young et al., "Cellulose: Structure, Modification and Hydrolysis," John Wiley and Sons, 1986, pages 102-110, indicate that the porosity of cellulose is increased with the sodium hydroxide solution. Japanese Patent Number JP-A-53-145 892 describes a method for cationizing the same raw papermaking materials. The process described therein does not obtain cationic groups inside the cellulose substance. This also S applies essentially to the processes described in Patent Numbers DE-A-23 49 501 and US-A-4,624,743. Patent Numbers EP-A-377, 046 and DE-A-2, 005, 408 describe macroporous pulp particles that are cationized. However, in this cationization, cationic groups are not obtained inside the cellulose substances themselves, but only on the external or internal surface of the porous articles. Japanese Patent Number JP-B-59-38 040 describes the use of water soluble cationic substances together with polyacrylamide. The problem of the invention is to provide new cellulose particles characterized by special properties and possible applications. The problem of the invention is also to provide cellulose particles that allow the substances that interfere in the paper circuit, in the machine circuit, or the water circuit, to be bound in the paper in as much as possible, and for consequently, they are removed from the circuit without presenting the problems described above. The problem of the invention is also to mention other possible applications of the cellulose particles. The invention is based on the discovery that this problem can be solved by cellulose particles having cationic groups, even inside the particles. In this way, at least 10 percent, preferably at least 50 percent, particularly at least 90 percent of the cationic groups, are present in the interior of the particles. As a result, cellulose particles having cationic groups bound to cellulose, distributed over the total cross-section of the particles, are thus provided.

For the particles to have sufficient cationicity, at least one cationic group must be present per 100, preferably 50 units of anhydroglucose of the cellulose. To produce the cellulose particles of the invention, the cellulose is reacted with a cationizing agent. The cellulose used can be unsubstituted pulp, but also substituted celluloses, in particular ester or cellulose ether, such as methylcellulose, carboxymethylcellulose, cellulose sulfate, cellulose acetate, or chitosan. The degree of substitution (GS) must be less than 1, that is, no more than one of the three OH groups of the anhydroglucose units of cellulose must be substituted on average. The degree of substitution should not be too great, so that a sufficient number of hydroxyl groups are available to react with the cationizing agent. In addition, alkaline cellulose, in particular sodium cellulose, such as cellulose can be used. The reaction of the cellulose with the cationizing agent can be carried out as a reaction of solids. The cellulose used can be alkaline cellulose, which is reacted with the cationizing agent in a kneader. In order to produce the cellulose particles of the invention, the cellulose can also be dissolved, and the dissolved cellulose can be mixed with the cationizing agent, on which the dissolved cellulose cationized in the cellulose particles is precipitated. The dissolution of the cellulose can be done by converting the cellulose with a solution of sodium hydroxide and carbon disulfide in sodium xanthogenate, but also by dissolving it in N-methylmorpholine N-oxide, lithium chloride of dimethylacetamide, copper tetraamine, copper (II) hydroxide, cupriethylenediamine, or cuprammonium. The N-methylmorpholine N-oxide monohydrate has a melting point of about 70 ° C. Therefore, it can easily be recovered as solids. In contrast to the xanthogenate, a bad odor does not occur, and waste materials such as sodium sulfate are not obtained. In the case of water soluble cellulose derivatives, water can be used as a solvent. The water soluble cellulose derivatives are preferably prepared by the viscose process. The cationic groups can be linked covalently to the hydroxyl groups of the cellulose. However, a bond is also possible by means of ionic and / or hydrogen bridges. The cationizing agents used can be aluminum salts, such as polyaluminium chloride or sodium aluminate. The polyaluminum chloride may be partially hydrolyzed. The aluminate is precipitated together with the xanthogenate with sulfuric acid. The cationizing agents used may also be cationic polyelectrolytes, such as polydialkyldiallylammonium salts, in particular polydial-quildiallylammonium chloride (poly-DADMAC), dicyandiamide, dicyandiamide condensates, polyamines, polyimines, such as polyethylene imine, or ionenes. The cationizing agents used may furthermore be reactive monomers, for example primary, secondary, and terpene amines, quaternary ammonium bases, each having at least one residue which reacts with a hydroxyl group of the cellulose. If the cationizing agent does not react with the hydroxyl groups of the anhydroglucose units of the cellulose, as in the case of the aluminum salts and the cationic polyelectrolytes, the solubility of the cellulose does not change much or nothing. In this case, the ratio of the cationizing agent to the cellulose can fluctuate within wide limits. However, normally the weight ratio of aluminum salts or cationic polyelectrolytes to cellulose is between 0.03: 1 and 1: 1, based on absolutely dry substances (dry abs). However, the reactive monomers are preferably added to the cellulose in an amount such that the degree of substitution (GS) is not greater than 0.2. Otherwise, cellulose particles with excessive water solubility can be present. The cationizing agent with reactive groups, ie reactive monomers, used can be in particular 2-chloroethane, trimethylammonium chloride, or propoxytrimethylammonium chloride. By precipitating the dissolved cellulose with a high degree of substitution, for example carboxymethylcellulose, in an aqueous solution with cationic polyelectrolytes, in the same manner the cationized cellulose particles of the invention can be obtained. Since the cationic charges in the cellulose particles of the invention are predominantly fixed inside the particles, the particles can be beaten, (milled) to make other charges accessible, which can act as functional groups. If reactive monomers are used as a cationizing agent, the reactive groups are residues that react with the cellulose hydroxyl groups. The reactant residue can be, for example, a halogen atom, epoxy groups, or imino group. In order to form an epoxy group, for example, a halogen atom can be bonded with a carbon atom, and a hydroxyl group with the adjacent carbon atom, of an alkyl residue of the amine or quaternary ammonium base . For example, the ammonium compound can be 3-chloro-2- (hydroxypropyl) -trimethylammonium chloride. In order to prevent the crosslinking of the individual cellulose fibers, in particular in the case of dicyandiamide and other polyelectrolytes, the cellulose can be reacted at a relatively high dilution with the cationizing agent. That is, when mixed with the cationizing agent, the dissolved cellulose is present in a concentration of preferably not more than 2 weight percent, particularly not more than 1 weight percent. The reaction of the dissolved cellulose with the cationizing agent is preferably done with stirring, over a period of time, for example, from 10 seconds to 30 minutes, depending on the reactivity of the cationizing agent. If the reaction time is too long, there is the aforementioned danger of crosslinking. The precipitation of the dissolved cationized cellulose can be done, for example, through fine centrifugal jets in precipitation baths. If the dissolved cellulose used is cellulose xanthogenate, the precipitant may be, for example, a polyaluminium chloride or sulfuric acid, whereby, the sulfuric acid may optionally have added salts, v. g., a sulfate such as sodium or zinc sulfate. As a result, the cellulose particles can also be obtained by the addition of a precipitator to the cationized cellulose dissolved with stirring, and in this way precipitation is caused directly in the reactor. The size of the cellulose particles, or the length of the precipitated cellulose fibers, then depends on, among other things, the dilution of the dissolved cationized cellulose, and the rate of agitation during precipitation. Preferred cationized cellulose particles have an average particle size of 0.001 to 10 millimeters, in particular an average particle size of 0.1 to 1 millimeter. The particles are preferably spherical. However, they can also exist in the form of fibers. A desired size and structure of the cellulose particles can also be obtained in particular by shaking. To crush the cellulose particles, a wide variety of beating apparatuses can be used, in particular standard pulping equipment such as a Jo ro mill, a conical refiner, or disk refiner. The blenders used by custom to beat the paper fibers are also very suitable. The shake causes a substantial enlargement of the surface of the cellulose particle, and therefore, a greater cationicity and efficiency.

The only figure shows the cellulose particles in a dark field image. The particles are in a swollen state. The particles are actually spherical in their three-dimensional form, but are crushed between the portaob-bosos in the image. The factor of enlargement is 100. The structure of fibrilo aleatory is easily recognized, with fibrils in the scale of 10 to 50 microns. When cellulose particles are used in papermaking, the size of the particles obviously should not be greater than the thickness of the paper, whereas a fiber structure may be convenient. When the cationized cellulose fibers are used as a means to fix the interfering substances in the paper, they should not be greater than 0.5 mm, in order to eliminate the formation problems. The cationized cellulose fibers are preferably not greater than 0.1 millimeters in length. For other applications, for example, as a flocculant, in particular a flocculant for the purification of waste water, an average particle size of 0.1 to 1 millimeter is usually preferred. The cellulose particles are used as a solid or in the form of a suspension. The cellulose particles of the invention can be termed insoluble in water. This means that cellulose particles virtually do not dissolve in water at normal residence times and application methods. Residence times are on the scale of minutes. In the cellulose particles of the invention, the cationic groups are covalently bonded to the cellulose, or immobilized within the cellulose membrane. This covalent bond or immobilization prevents any significant loss of cationic activity during the use of the cellulose particles. The cellulose particles of the invention are used as solids, whereby they can contain 80 percent water. It is also conceivable to dry these cellulose particles and use them as dry granules. Alternatively, they can be used in the form of a suspension, for example with a solids content of 3 percent, or in the form of a paste with higher solids contents of up to 20 percent. After the precipitation of the dissolved cationized cellulose polymer chains, the cationic groups are contained in the cellulose particles uniformly distributed over their total cross section. The cationic groups present inside the cellulose particles are insensitive to mechanical action, for example, they are not removed by the shear forces caused by the agitation.

The cationized cellulose particles of the invention are an outstanding means for fixing interfering substances in the paper, which are present in the water circuits during papermaking. The use of cationic cellulose has no adverse effect on the properties of paper, unlike the known means for fixing interfering substances in paper, such as bentonite. At the same time, the cationized cellulose of the invention causes fine substances, in particular fine filler particles, to bond with the fibers, thereby improving the retention of fine substance or ash, and the distribution of fine substances on paper, and obtaining a more homogeneous sheet. That is, the cationized cellulose of the invention allows fine substances to be retained both on the side of the cellulose particle / filler mixture that faces the wire, and on the upper side. Above all else, however, the cationized cellulose of the invention causes anionic debris, which (as mentioned above) is present in a greater amount in the current paper machine circuit, to bind with the cellulose particles. of the cellulose particle / filler mixture, and therefore, discharge from the circuit. In particular, when the cationized cellulose fiber of the invention is short, ie has a length of, for example, 0.1 millimeters or less, this increases in addition in a demonstrable way the strength of the filled paper, a property crucial to judge the quality of the paper. This is possibly due to the fact that the short cationized cellulose particles are collected in the spaces between the longer cellulose fibers of the paper, and bridge there, between the cellulose fibers of the paper. In the paper industry, therefore, the cationized cellulose particles of the invention can be used as a means to increase the strength of the filled paper ", or as a means to fix the interfering substances in the paper, stirring in this way In addition, the cationized cellulose particles of the invention are a means of retaining fine substances in paper during papermaking, ie, fine ash or other filler particles or other particles. of fine solids that are to be incorporated into the paper, are retained by the cationized cellulose particles of the invention, that is, they are protected from washing, and therefore, they are maintained in the paper.This achieves greater homogeneity and dimensional stability Because thin materials are better bonded, this reduces the tendency to form dust during the processing of the paper. In addition, the cationized cellulose particles of the invention lead to an increase in the strength of the filled paper. Accordingly, the invention includes in particular a method for producing the paper, which uses a closed water circuit to which the cellulose particles of the invention are added. In this way, the interfering substances are bonded and made harmless. In general, 0.1 kilograms of cationized cellulose particles are added per tonne of paper supply (absolutely dry). The upper limit is generally 10 kilograms / ton for cost reasons. At the same time, the cationized cellulose particles of the invention are an auxiliary flocculation aid for poorly precipitable organic sludge. In this way, the cationized cellulose particles of the invention can be used in particular as a flocculant for the purification of the waste water, especially in the clarification plants to flocculate the digested sludge. Compared with conventional flocculants, in particular polyelectrolytes, the cationized cellulose particles of the invention have a very large stable cationic surface on which the substances to be flocculated can precipitate. In contrast to conventional flocculants, in this way a more stable flocculation is obtained which can also be better dehydrated. It has turned out that the use of the cellulose particles of the invention, in combination with water-soluble polymers, produces surprising results, both when the cellulose particles are used in the drying of the sludge, and when they are used in the manufacture of the paper. Especially good results are achieved in combination with water-soluble cationic polymers. However, combinations with anionic or nonionic polymers are also conceivable. An especially convenient combination has turned out to be * the combination of the cellulose particles of the invention with water-soluble cationic polyacrylamide. In addition to the polyacrylamide, it is possible in particular to use polyethyleneimine and water-soluble cellulose derivatives, for example hydroxyethylcelluloses or cationic carboxymethylcelluloses. In the drying of the sludge, the water-insoluble cellulose particles of the invention are preferably added in admixture with the water-soluble polymers. However, a separate addition is also possible. Based on the water soluble polymer, for example acrylamide, the addition of the cellulose particles of the invention can be within very wide limits, from 0.1 to 99.9 weight percent. However, the preferred weight percentages of the cellulose particles are from 1 to 50 percent, preferably from 1 to 10 percent, particularly from 2 to 7 percent, and in particular from 3 to 5 percent. The percentage of cellulose particles is determined by the quality of the sludge, the desired dry content of the sludge, and the production capacity. When the cellulose particles of the invention are used in combination with a cationic polymer, the two components are preferably premixed, stored, and transported dry. Before application, the mixture dissolves or disperses in water, and is loaded into the sludge directly without filtration, which is not necessary for the sludge. This preferred use of the mixture of cellulose particles and polymers is only possible with cationic polymers, and not with anionic polymers, since the latter would react with the cationic cellulose particles. Accordingly, the anionic polymers are added separately from the cellulose particles. When the cellulose particles of the invention are used in combination with the anionic polymer, the cellulose particles are stored, transported, prepared, and introduced separately, in a dry form or in the form of an aqueous suspension. In the same way, the anionic polymer can be stored and transported dry, dissolved in water, or as an emulsion. In any case, the two components must be charged to the sludge separately as an aqueous solution or suspension. Any possibility of loading can be used, first the cellulose particles or first the polymer. The synergistic effect obtained by the combination of the water-soluble polymers and the water-insoluble cellulose particles is impressive. However, the mechanism of action is unknown. For example, tests with biological sludge have shown that the use of 94.3 weight percent polyacrylamide and 5.7 weight percent cellulose particles, instead of the use of pure polyacrylamide, allows for an increase in the speed of the band press from 62 to 100 percent, and an increase in sludge production from 28 cubic meters / hour to 33 cubic meters / hour. • Other tests related to a higher dry content have also given impressive results. Therefore, the addition of only 3 weight percent of cellulose particles to the polyacrylamide used resulted in an increase in the dry content after pressing from 48 to 53 percent. The combined use of water-soluble cationic polymers and the water-insoluble cellulose particles of the invention has also shown surprising results, particularly in paper-making. In papermaking, a separate addition of cellulose particles and water soluble polymers is preferred. It is convenient to filter the water-soluble polymer as a solution continuously before the point of introduction, in order to filter the gel particles that impair the quality of the paper. It is better to add the cellulose particles before, and the water soluble polymers only afterwards. In particular, it is convenient to add the cellulose particles in the initial phase of papermaking, while the water-soluble polymers are added in the final phase shortly before the formation of the sheet. Expressed as a time history, and assuming a total circulation time of approximately 90 seconds, the cellulose particles are added in 30 to 60 seconds before feeding the paper supply to the headbox, and the water soluble polymers approximately 10 to 20 seconds before. The mixing ratio of cellulose particles and cationic polymers varies within wide limits, for example from 90:10 to 10:90. However, it is preferable to add from 40 to 60 percent of cellulose particles, based on weight. The preferred amount depends on the grade of paper, among other things. Higher percentages are preferred for paper with little filling. In papermaking, the cellulose particles are preferably added in the form of a suspension in water, for example a 3 percent suspension. The polymer solution is added as an aqueous solution, for example in a concentration of 0.2 to 0.8 percent. When anionic water-soluble polymers are used in combination with the cellulose particles, the same mixing ratios and addition forms or addition times are preferred. It has turned out that the use of the cellulose particles of the invention in papermaking can achieve greater amounts of filler in the paper. This is desirable for economic reasons, since fillers are cheaper than paper fibers. Fillers achieve better properties, in particular a better opacity and possibility of printing. An additional advantage that has arisen from the addition of cellulose particles, is a better paper formation, and therefore, a better paper quality. The term "cellulose particles" is also referred to in this patent application, to fibers of any shape and length, in particular spun fibers. Cellulose fibers have various applications in the industrial and textile fields. The special characteristic of the fibrous cellulose particles of the invention is its highly improved dyeing behavior. In particular, the fibers can be dyed with favorable anionic dyes. The stained fibers are characterized by a particular color firmness, which is due to the fact that the cationic groups which react with the dyes are immobilized in the cellulose fiber, or are covalently bound to the cellulose molecules. The following examples will further explain the invention. EXAMPLE 1 An aqueous sodium cellulose xanthogenate solution is diluted to 8.5 weight percent, with 0.02 N sodium hydroxide, in a ratio of 1:25. 250 milliliters of the diluted sodium cellulose xanthogenate solution are mixed, with stirring (350 rpm), with 1 milliliter of a 40 weight percent aqueous solution of dicyandiamide. After 5 minutes of agitation, the speed is increased (600 rpm), on which, 5 milliliters of an aqueous solution of aluminum polychloride at 18 percent are added dropwise. The precipitated cellulose fibers are washed with water until the supernatant no longer has cationic charges. Example 2 100 kilograms of pulp are converted with 18 percent aqueous sodium hydroxide in alkaline cellulose (CA). 20 kilograms of 3-Cl-2-hydroxypropan-trimethylammonium chloride are added to the compressed alkaline cellulose. The reaction is carried out in the mixer with cooling at 35 ° C for 6 hours. The neutralization is then carried out with hydrochloric acid and washed with water. The obtained cationized cellulose is dried and beaten to the necessary particle size. Example 3 To detect the cationicity of the cellulose fibers obtained in Example 1, methyl red is used as an anionic dye. The cationicity of the conventional, precipitated unmodified cellulose fibers was compared to the cationized cellulose fibers produced according to Example 1. The fibers were mixed for this purpose with the methyl red solution, and then centrifuged . After centrifugation, the color of the fibers and the coloration of the supernatant were judged. In the cationized cellulose fibers produced according to Example 1, there was a clear coloration of the fibers, and at the same time a discoloration of the supernatant, in contrast to the unmodified cellulose fibers. As a control, methylene blue was used as a cationic dye. With weakly anionic unmodified cellulose fibers, a coloration of the fibers was observed, while the cationized cellulose fibers produced according to Example 1 were not colored. Also, in the cationized fibers there was no discoloration of the supernatant. Example 4 To verify the efficiency of the cellulose fibers produced according to Example 1, a supply of paper from a production of wood and ash (raw material for natural rotogravure) was mixed with the cationic cellulose fibers produced according to with Example 1, where sheets were formed by the standard method. The weight of the sheet, the explosion pressure, the tear propagation force, and the formation in the paper were judged. It turned out that the cationized cellulose fibers produced according to Example 1 had a positive influence on the distribution of the fine substances, including the ash distribution, and the strength and the formation compared to a comparative test carried out simultaneously (without the addition of these cationized fibers). Example 5 With the cationized cellulose fibers produced according to Example 1, with an average length of about 4 centimeters, a flocculation test was carried out with digested sludge from a waste water rinse plant which is difficult to flocculate, since it is very thin. It turned out that the cationized cellulose fibers produced good flocculation, a high settling speed, and a clear supernatant, while a comparative test with a conventional flocculant, ie polyacrylamide, showed only little flocculation. Example 6 An 8.5 weight percent aqueous solution of sodium cellulose xanthogenate was diluted with an aqueous solution of sodium hydroxide (4 grams / liter) to 4.25 percent (as cellulose). The cationizing agent, a 40 percent aqueous solution of a formaldehyde condensate of dicyandiamide (a product commercially available from SKW Trostberg, Melflock C3), was diluted with water to an active concentration of 2 percent by weight. 600 milliliters of the resin solution of the 2 percent dicyandiamide formaldehyde condensate diluted above, were agitated with a stirrer at 750 rpm, and then 940 milliliters of the above sodium cellulose xanthogenate solution, diluted to 4.25, were slowly added. percent, to the stirred cationizing agent. This mixture, which already contained precipitated particles, was then added slowly to the precipitation bath. The precipitation bath consisted of 3,000 milliliters of aqueous solution containing 35 grams of sulfuric acid (98 percent), which was likewise continuously stirred. In this precipitation bath there was a quantitative precipitation of the product. More acid was added if necessary to ensure a pH of less than 2. The precipitated fibrous product was filtered through a filter funnel adapted with fine plastic gauze sieve, recovered and stirred in 1,000 milliliters of deionized water. The pH of adjusted between 4.5 and 5.5 with a diluted solution of sodium hydroxide. The precipitated product was filtered once more through a filter funnel adapted with a fine plastic gauze sieve, repeatedly recovered and stirred in 1,000 milliliters of deionized water, and filtered until no longer detectable. significant additional cationicity in the supernatant. During this washing step, the residual cationicity, if any, was measured by titration of an aliquot against a standardized anionic polymer, with a particle charge detector (μTek PCD 02), or was detected by an appropriate dye ( blue of ortho-toluidine) as an indicator. The wet product (solids content of approximately 12 to 20 percent) was removed from the filter and then stored in this state.

Example 7 An 8.5 weight percent aqueous solution of sodium cellulose xanthogenate was diluted with an aqueous solution of sodium hydroxide (4 grams / liter) to 1 percent (as cellulose). The cationizing agent, a 40 percent aqueous solution of a diallyldimethylammonium polychloride (a commercially available product, FLOERGER FL 45 C), was diluted with water to an active concentration of 1 percent by weight. 2,000 milliliters of the sodium cellulose xanthogenate solution, diluted at 1 percent, were shaken with a high shear agitator, without allowing air to enter the solution. Subsequently, 600 milliliters of the 1 percent diallyldimethylammonium polychloride solution was added to the stirred solution over a period of 30 seconds. The resulting mixture was stirred vigorously for an additional 1 minute. The reaction of the cationizing agent with the cellulose xanthogenate solution causes an immediate and increasing rise in the viscosity in the mixture. For example, if undiluted, viscous, and poly-DADMAC (at the contents of the above solids) are mixed together, the mixture immediately solidifies, subsequently separating into a solid phase and a liquid phase. 1,000 milliliters of an aqueous solution containing 25 grams of sulfuric acid (98 percent) was added to the stirred mixture, and thus precipitation was performed.

More acid was added if necessary to ensure a pH less than 2. The precipitated fibrous product was filtered through a filter funnel adapted with a fine plastic gauze sieve, recovered and shaken in 500 milliliters of deionized water. The pH was adjusted from 4.5 to 5.5 with a dilute solution of sodium hydroxide. The precipitated product was filtered again through a filter funnel adapted with a fine plastic gauze sieve, repeatedly recovered and shaken in 500 milliliters of deionized water, and filtered until no significant cationicity could be detected in the sample. supernatant During this washing step, the residual cationicity was measured, if any, by titration of an aliquot against a standardized anionic polymer, with a particle charge detector (μTek PCD 02), or was detected by an appropriate dye ( blue of ortho-toluidine) as an indicator. The wet product (solids content of about 12 to 20 percent) was removed from the filter, and then stored in this state.

Example 8 The same procedure as in Example 6 was also conducted with a different cationizing agent, a 20 weight percent solution of polyethylenimine (a product commercially available from BASF, Polymin SK). The polyethyleneimine solution was diluted with water to a concentration of 2 percent. 600 milliliters of this diluted solution of cationizing agent was used in the reaction. Example 9 The same procedure was also conducted as in the Example 6, with a different cationizing agent, a 50 weight percent aqueous solution of a polyamine (a commercially available product, FLOERGER FL 17). The polyamine solution was diluted with water to a concentration of 2 percent. 600 milliliters of this diluted solution of cationizing agent was used in the reaction. Example 10 An aqueous solution at 8.5 weight percent of sodium cellulose xanthogenate was diluted with an aqueous solution of sodium hydroxide (4 grams / liter) to 4.25 percent (as cellulose). The cationizing agent, a solution of reactive cationic monomers (a product commercially available from Raisio, RAISACAT 65), comprised the following ingredients (concentration of about 70 percent): 1) 3-Chloro-2-hydroxypropyl trimethylammonium chloride 2 percent. 2) 2, 3-epoxypropyltrimethylammonium chloride approximately 66 percent. 3) Chloride of 2, 3-dihydroxypropyltrimethylammonium about 3 percent. 2.2 grams of the commercial product was diluted to 200 milliliters with deionized water. 470 milliliters of the above sodium cellulose xanthogenate solution diluted to 4.25 percent, were stirred at 800 rpm with a propeller agitator, without allowing air to enter the solution. Subsequently, 200 milliliters of the diluted solution of the above cationizing agent was added over a period of 3 seconds to the stirred solution. The resulting mixture was stirred for another 30 minutes. 670 milliliters of an aqueous solution containing 18 grams of sulfuric acid (98 percent) was added to the stirred mixture, and thus precipitation was performed. More acid was added if necessary to ensure a pH less than 2. The precipitated fibrous product was filtered through a filter funnel adapted with a fine plastic gauze sieve, recovered and shaken in 500 milliliters of deionized water. The pH was adjusted from 4.5 to 5.5 with a dilute solution of sodium hydroxide. The precipitated product was filtered once more through a filter funnel adapted with a fine plastic gauze sieve, repeatedly recovered and stirred in 500 milliliters of deionized water, and filtered until no additional cationicity could be detected. meaningful During this washing step, the residual cationicity, if any, was measured by titration of an aliquot against a standardized anionic polymer solution, a particle charge detector (μTek PCD 02), or was detected by an appropriate dye ( blue of ortho-toluidine) as an indicator. The wet product (solids content of about 12 to 20 percent) was removed from the filter, and then stored in this state. Example 11 The same procedure as in Example 7 was also conducted, with. a different cationizing agent, a 40 percent by weight aqueous solution of a special highly branched polydiallyldimethylammonium chloride. The poly-diallyldimethylammonium chloride was diluted with water as in Example 7. Example 12 The same procedure as in the Example 7, with a different cationizing agent, a 48.5 weight percent aqueous solution of a special low molecular weight polydiallyl-dimethylammonium chloride. The polydiallyldimethylammonium chloride was diluted with water to a concentration of 1 percent as in Example 7. Example 13 The same procedure as in the Example 6, with a different cationizing agent, a 40 weight percent solution of a copolymer of diallyldimethylammonium chloride and acrylic acid, the monomeric component of acrylic acid constituting less than 10 percent. The copolymer solution was diluted with water to a concentration of 1 percent in this example. Example 14 An 8.5 weight percent aqueous solution of sodium cellulose xanthogenate was diluted with an aqueous solution of sodium hydroxide (4 grams / liter) to 2 percent (as cellulose). The cationizing agent, a 29 percent aqueous solution of an aluminum polychloride (a product commercially available from Ekokemi, EKOFLOCK 70), was used in undiluted form. 1,000 milliliters of the previous sodium cellulose xanthogenate solution diluted 2 percent (as cellulose) were agitated with a propeller agitator vigorously, but without allowing air to enter the solution, subsequently 21 milliliters of the solution was added. undiluted cationizing agent before the stirred solution for a period of 30 seconds. The resulting mixture was stirred vigorously for an additional 1 minute. One thousand milliliters of an aqueous solution containing 20 grams of sulfuric acid (98 percent) was added to the stirred mixture, and in this way precipitation was performed.

More acid was added if necessary to ensure a pH less than 2. The precipitated fibrous product was filtered through a filter funnel adapted with a fine plastic gauze sieve, recovered and shaken in 500 milliliters of deionized water. The pH was adjusted from 3 to 4 with a dilute solution of sodium hydroxide. The precipitated product was filtered once more through a filter funnel adapted with a fine plastic gauze sieve, repeatedly recovered and stirred in 500 milliliters of deionized water, and filtered. The wet product (solids content of about 12 to 20 percent) was removed from the filter, and then stored in this state. Example 15 An 8.5 weight percent aqueous solution of sodium cellulose xanthogenate was diluted with an aqueous solution of sodium hydroxide (4 grams / liter) to 2 percent (as cellulose).

The cationizing agent, a 45 percent aqueous solution of a sodium aluminate (a commercially available product in Mare, Fimar A 2527), was used in undiluted form. 1,000 milliliters of the previous sodium cellulose xanthogenate solution diluted at 2 percent, were agitated with a propeller agitator vigorously, but without allowing air to enter the solution. Subsequently, 24 milliliters of the above undiluted cationizing agent solution was added to the stirred solution for a period of 30 seconds. The resulting mixture was stirred vigorously for an additional 1 minute. Then 1,000 milliliters of an aqueous solution containing 37 grams of sulfuric acid (98 percent) was added to the stirred mixture, and in this way precipitation was performed. More acid was added if necessary to ensure a pH less than 2. The precipitated fibrous product was filtered through a filter funnel adapted with a fine plastic gauze sieve, recovered and shaken in 500 milliliters of deionized water. The pH was adjusted from 3 to 4 with a dilute solution of sodium hydroxide. The precipitated product was filtered once more through a filter funnel adapted with a fine plastic gauze sieve, repeatedly recovered and stirred in 500 milliliters of deionized water, and filtered. The wet product (solids content of approximately 12 to 20 percent) was removed from the filter, and then it was stored in this state. Example 16 The same procedure as in Example 7 was also conducted with a modified cellulose (sodium methylcellulose xanthogenate). Low-substitution water-insoluble methylcellulose was used in place of the unmodified cellulose. Example 17 A solution of cellulose in lithium chloride, dimethylacetamide (DMA), and water, is prepared as follows. The pulp of cellulose that has been bleached and stored wet, is added to a mixture of lithium chloride and dimethylacetamide, in such a way that the components are present in the following proportion: 5 parts of cellulose (dry weight), 11 parts of chloride of lithium, 82 parts of dimethylacetamide, and some water (from the wet pulp). This mixture is homogenized with a high shear agitator, and heated under vacuum over a water bath, until the water content of the mixture is less than 3 percent. A drip sprayer is used to aid in the removal of water. The resulting suspension is cooled in a refrigerator at 5 ° C, and held for 1 day at this temperature. Periodic stirring aids the dissolution of the suspended cellulose. The resulting solution is heated to 50 ° C, and filtered through a fine sieve. A 40 weight percent aqueous solution of a diallyldimethylammonium polychloride (a commercially available product, FLOERGER FL 45 C) is used as the cationizing agent. Based on the dissolved cellulose, the 10 percent cationizing agent (as an active substance) in undiluted form is added slowly with continuous mixing. The small amount of water introduced into the solution with the cationizing agent normally does not interfere with the equilibrium in solution of the cellulose-lithium chloride-dimethylacetamine-water, so that the cellulose does not precipitate, but the viscosity of the resulting mixture begins to rise rapidly, and immediately follows the next stage. The resulting mixture, at a temperature of 50 ° C, is poured into the swirl region of a stirred aqueous precipitation bath, whereby the cationized cellulose is precipitated. The precipitated fibrous product is filtered from the mixture through a filter funnel adapted with a fine plastic gauze screen. The filtrate is stirred in deionized water and filtered again. This washing process removes the residual amounts of salts and DMA from the product. The product is washed once more with deionized water and filtered. This process is repeated until a significant additional cationicity can be detected in the filtrate water. The wet product (solids content of about 12 to 20 percent) is removed from the filter, and then stored in this state. Example 18 A cellulose solution in N-methylmorpholine (NMMO) oxide was prepared as follows. A mixture of N-methylmorpholine- / water oxide is analyzed for the water content. This is usually about 30 percent water at this stage. Pure powdered cellulose was added to the above mixture to a level to give 3.6 percent by weight (based on the N-methylmorpholine oxide). This mixture was then placed in a vacuum flask adapted with a stirrer and a spray tube, which is used to drip dry nitrogen gas under the surface of the liquid. The flask was then heated to 95 ° C in a water bath. A vacuum was applied, the agitator was turned on, and a small amount of nitrogen was allowed to bubble through the liquid phase, thereby progressively removing the water.

At a certain concentration of water and N-methylmorpholine oxide (about 88 percent N-methylmorpholine oxide) the cellulose is dissolved. Then the nitrogen purge and the vacuum pump stopped. In this experiment, it. used a 40 percent solution of a polydiallyldimethylammonium chloride (a commercially available product, FLOERGER FL 45 C) as a cationizing agent. Based on the dissolved cellulose, the cationizing agent was added at 10 percent (as an active substance) in undiluted form to the cellulose solution with stirring. The small amount of water (approximately 0.5 percent) introduced into the N-methylmorpholine oxide solution by the cationizing agent usually does not alter the solution balance of cellulose-N-methylmorpholine oxide / water, as to cause the cellulose precipitation. The resulting mixture was pumped using a gear wheel pump through a filter packed with glass wool, and then through a centrifugal jet into a water bath, where the cationized cellulose coagulated and could be formed into fibers . These fibers were filtered, washed, and dried, and then cut to a length of about 1 centimeter. Example 19 A 2 weight percent aqueous solution of carboxymethylcellulose (CMC) with a degree of substitution of about 0.55 was prepared, and stirred for 1 hour to ensure complete dissolution of the carboxymethylcellulose. The cationizing agent, a 40 percent aqueous solution of a dicyandiamide formaldehyde condensate resin (commercially available from SKW Trostberg, Melflock C3), was diluted with water to a concentration of 4 percent by weight. 1,000 milliliters of the above 2 percent carboxymethylcellulose solution was stirred at 800 rpm with a propeller stirrer, and subsequently 125 milliliters of the above aqueous solution of dicyandiamide formaldehyde condensate resin diluted to 4 percent over a period of time were added. of 10 seconds. This mixture, which already contained the precipitated cationized cellulose, was stirred for another 5 minutes. The precipitated product was filtered through a filter funnel adapted with a fine plastic gauze screen, repeatedly recovered and stirred in 500 milliliters of deionized water, and filtered until no significant additional cationicity could be detected in the sample. supernatant During this washing step, the residual cationicity, if any, was measured by titration of an aliquot against a standardized anionic polymer solution with a particle charge detector (μTek PCD 02), or was detected by a dye. adequate (ortho-toluidine blue) as an indicator. The wet product (solids content of approximately 12 to 20 percent) was removed from the filter and then stored in this state. Example 20 The solids content of the cationized cellulose of Example 6 was measured. Sufficient wet product was recovered to give 10 grams of the dried product, and filled to 200 grams with water. This dispersion was transferred to a Jokro mill, and beat for 10 minutes at 1,500 rpm. This type of mill is normally used in a paper laboratory to test the characteristics of the fibers for paper milling. The above shake parameters are comparable to those used to test fibers for papermaking. The procedure was also repeated using beating times of 5, 15, 30, and 45 minutes. After measuring the solids content, the whipped particles were diluted to obtain a 3 weight percent suspension. The wet product (solid content of about 3 percent) was stored in this state. Example 21 The cationicity of the different products of Example 20 was measured by titration against standardized 0.001 N sodium polyethylene sulphonic acid (Na-PES) using ortho-toluidine blue as an indicator of the end point. In an alternative way, the cationicity was measured by reverse titration as follows. The product obtained by the above methods was mixed with an excess amount of standardized 0.001 N sodium polyethylene sulphonic acid (Na-PES) and stirred for 1 hour. The solids were then centrifuged, and an aliquot of the clear supernatant against 0.001 N diallyldimethylammonium polychloride (poly-DADMAC) was titrated on a particle charge detector. The loading of the product was calculated from the consumption of diallyldimethylammonium polychloride. The cationicity measured by reverse titration is usually higher than the directly measured cationicity. This can be explained by the fact that, during the reverse titration, the reagent can penetrate into the cellulose structure, due to the longer duration, and in this way reacts with less accessible charge carriers. The following table shows the cationicity of the product of Example 6 as a function of different beating times. It can be seen that the cationicity increases with an increase in the beating time, which can be explained by the fact that a longer beating reduces the size of the particles, and consequently, the specific surface area and the available charge.

Example 22 The nitrogen content of the dry product of Example 6 was measured using the Kjeldahl method. In the same manner, the nitrogen content of the dry cationizing agent of Example 6 was measured. The reference value used for the nitrogen content was uncatalyzed cellulose precipitated in acid as sodium cellulose xanthogenate. However, the values were below the detection limit of this method.

By comparing the amount of cationizing agent used and the nitrogen content in the finished product, the yield of the reaction can be derived. Depending on the choice of the cationizing agent, it is typically between 60 and 90 percent. EXAMPLE 23 The solids content of the cationized cellulose made with a raw material similar to that of Example 6 was measured. Sufficient wet product (solids content of 15 percent) was added to give 380 grams as a dry product to the borer of a Sulzer Escher Wyss P 12 laboratory conical refiner. This refiner is normally used in the paper laboratory to test the characteristics of the fibers for papermaking. The above quantity of cationized cellulose was filled with water to 12.5 liters, and dispersed for 1 minute. Then the paste was transferred to the refiner section of the apparatus, the air was removed, and the product was pumped under continuous circulation through the refiner for 5 minutes, and in this way it was beaten. The power setting was maintained at 350 watts by automatic control during the beating, and the rotor speed was 1,500 rpm. The beating energy for the cationized cellulose processing was approximately 0.08 kW / kg. The above beating parameters are comparable to those used to beat fibers for papermaking. The shake of the product was also conducted at different times (1, 2, 3, 4, 6, 7, 8, 9 and 10 minutes). After beating, the solids content was measured again, the whipped product was diluted to a concentration of 3 percent, and stored in this state. Example 24 The product of Example 6 was dried in a hot air oven at 105 ° C, until the moisture content was between 4 and 8 percent. In this way, the product could be easily decomposed into small lumps, the consistency being comparable to hard bread, and stored for some time in this state. Example 25 The dry product of Example 24 was moistened with water for about 10 minutes, and then beaten in a Jokro mill for 10 minutes as described in Example 20. After beating, the solids content was measured again, and the Whipped product was diluted to a concentration of 3 percent, and stored in this state. Example 26 The dry product of Example 24 was milled in the dry state in a Braun Model 4045 coffee mill to the finest position for 5 minutes, and then stored in this state. Example 27 The cationized cellulose of Example 6 was stirred for 10 minutes using the procedure of Example 20. The resulting fine solid particles were filtered from the whipped pastes on a microfine synthetic filter cloth, and subsequently dried at 90 ° C. In this state, the product could be easily decomposed into small lumps, comparable to hard bread, and stored in this state. Example 28 The product of Example 20 was centrifuged in a? ------ Centrifugal laboratory for 5 minutes at 1,000 rpm. The aqueous phase of the supernatant was decanted. The pasty compound that remained in the tubes had a solids content of about 18 percent, and was stored in this state. Example 29 The product produced in Example 28 was diluted with water to about 3 percent, and stirred slowly. The very fine pasty product could thus be dispersed in water again very quickly and within a short time. Example 30 The product produced in Example 28 was added to a solution of a water-soluble cationic polyacrylamide.

(FLOERGER FO 4190) as it was used for mud dehydration. In this case, 5 percent of the cationized cellulose was added, based on the dry weight of the cationic polyacrylamide. The mixture was stirred slowly. The product could be dispersed in this way in the polyacrylamide solution very easily and within a short time. Example 31 The dry product of Example 27 was added to water, to give a concentration of 3 percent, and stirred for 10 minutes. A dispersion was then performed in a high shear mixer for 5 minutes, resulting in a homogeneous suspension. Example 32 The product made in Example 20, using a beat time of 10 minutes, was stirred slowly to keep the product uniformly dispersed. The stirring was turned off, and after 1 hour, it was found that the cationized cellulose particles had partially settled. After several days, a sediment paste formed that constituted approximately half the liquid volume. Again the agitator was connected, whereby this sediment could be dispersed evenly in the water. The product thus diluted, now with a solids content of about 3 percent, was pumped into a circuit using a diaphragm pump (maximum capacity of 23 liters / hour) adapted with ball valves on the suction and delivery sides , and with a suitable pipe with an internal diameter of 16 millimeters. After 24 hours of continuous circulation, there was no reduction in pumping efficiency. Another portion of the dispersed product (also now with a solids content of 3 percent) was pumped into a circuit using a small screw feed pump or "Mohno" (maximum capacity of 20 liters / hour) adapted with a rubber stator for the aqueous medium. After 24 hours of continuous circulation, there was no reduction in pumping efficiency. EXAMPLE 33 Dehydration of biological sludge The cationized cellulose of Example 20 was used as a 3 percent dispersion in combination with a cationic, water-soluble polyacrylamide-based flocculant used in the prior art to dehydrate sludge (commercially available as Allied Colloids, DP7-5636). This accelerated the dewatering of the biological sludge, and increased the solids content of the dehydrated sludge, comparing with the use of the cationic polyacrylamide flocculant alone. The sludge used in this field test is from a combined municipal / industrial sewer, and it contains a mixture of primary and biological sludge. This sludge was recovered from a point between the sludge thickener after the anaerobic digester and the final dehydration press, before any precipitants / flocculants were added. The solids content was approximately 2 percent. The standard powdery polymer used in this plant was prepared as a 0.3 percent by weight aqueous solution. This water-soluble cationic polymer was selected as the most suitable product after a series of optimization tests. The cationized cellulose was further diluted with water to a solids content of 0.3 percent. This means that any mixture of the two products will always have the same concentration of active ingredients. The following facility was used for laboratory tests. 1) A pitcher drainage test apparatus Britt (see the attached diagram) was adapted with a previously heavy black slat filter (Schleicher &Schüll 589, diameter of 110 millimeters, which does not leave ashes). They were not used in the sieve normally used in the paper laboratory for dehydration tests, nor the precision agitator. 2) The drain pipe, equipped with an on / off valve, was connected using flexible silicone tubing, to a container placed on a scale. The balance was programmed to send a recorded weight signal at set time intervals to a computer, where it was registered. This allowed the dehydration curves of the weight of the filtrate to be recorded against time. The collection container was also adapted with a flexible tube to a vacuum pump, in such a way that the preset vacuum level could be adjusted during dehydration. 3) The precision agitator supplied with the Britt jar was installed so that the contents of a 500 milliliter beaker could be shaken. 4) . Filter papers (Schleicher &; Schüll 589, black ribbon, diameter of 110 millimeters), dosing syringes, balance, drying oven, etc.). The following measurement procedure was used. A series of flocculating solutions was prepared by mixing a cationized cellulose dispersion at 0.3 percent with the cationic water-soluble polyacrylamide (PAA) flocculant at 0.3 percent to give a range of direct polyacrylamide through various mixtures , up to direct cationized cellulose. The concentration of active ingredients was the same in all mixtures. 500 milliliters of fresh untreated sludge, with a solids content of 2 percent, were placed in a beaker, and stirred at 200 rpm for 1 minute. Then 15 milliliters of the flocculant (45 milligrams) was added using a syringe. This simulates the dosage used in practice. The sludge thus treated was mixed slowly for another two minutes. During this time, the vacuum pump was turned on, in such a way that the vacuum could be stabilized. The filter paper of the Britt jar got wet, and the scale was zeroed. 130 milliliters of flocculated mud was added from the beaker to the Britt jar, thus forming a layer of mud approximately 1.5 centimeters deep. The valve between the Britt jar and the collection container was opened, and data transmission from the balance to the computer started. The weight of the filtrate in the collection vessel was thus recorded automatically during dehydration. When the sludge was completely dehydrated, as seen by a cessation of liquid entering the collection vessel, and by the air that was directed through the sludge to the collection vessel, or in the case of bad dehydration, by the filter that was blocked by fine substances, the test was stopped. The remaining sludge on the filter was tested for solids content. The filtrate was tested for turbidity and chemical oxygen demand (DOQ). The procedure was repeated for different flocculants. The weight results of the filtrate were plotted against the time for each of the flocculants used. The content of dry substance, as well as the turbidity of the filtrate and the chemical oxygen demand, were also tabulated against each flocculant used.

Results: Table 1 (Fanao dehydration rate) Table 2 (Solids content of dehydrated sludge Note: Samples marked with * could not be dehydrated within a reasonable time, since the filter was blocked with fine substances.

Table 3 (Turbidity and chemical oxygen demand of the filtrate) The replacement of approximately 4 percent of the water-soluble cationic polyacrylamide by the water-insoluble, cationized whipped cellulose particles produced a surprising and significant increase in the rate of dehydration for this sludge, together with a marked increase in the content of solids from the dehydrated sludge, and a reduction in the turbidity and the chemical oxygen demand in the filtrate.

EXAMPLE 34 Dehydration of primary sludge The same test procedure was used as in Example 33 for this sludge, with the exception of the following differences. The cationized cellulose used was that made in Example 7 with poly-DADMAC as the cationizing agent, beating the cellulose for 10 minutes by the procedure described in Example 20. The sludge used in this example was recovered from a mechanical wastewater plant industrial, where the wastewater is normally precipitated, sedimented, the sediment is concentrated in a sludge thickener, and then, after treatment with a water-soluble cationic polyacrylamide, it is dehydrated on a band press. The standard product used in this plant is known by the trade name Floerger FO 4190. The sludge used for the laboratory tests was recovered again from a point between the sludge thickener and the band press, before any flocculant was added. The solids content of this sludge was 2 percent.

Results: Table 4 (Weight of the filtrate during the dehydration time) Table 5 (Solids content of dehydrated sludge Note: Samples marked with * could not be dehydrated within a reasonable time, since the filter was blocked with fine substances.

Table 6 (Turbidity and chemical oxygen demand of the filtrate) The replacement of approximately 6 percent of the water-soluble cationic polyacrylamide by the water-insoluble, cationized whipped cellulose particles produced a surprising and significant increase in the rate of dehydration for this sludge, together with a marked increase in the content of solids from dehydrated sludge, and a reduction in turbidity and in the demand for chemical oxygen in the filtrate.

EXAMPLE 35 Coagulation agent in the treatment of waste water The washing water of a paper coating machine often contains anionically charged latex, which is a constant problem as an interfering substance when this wash water is again used in the papermaking, as is desirable. Normally it is required that this wash water be coagulated by neutralization, in such a way that it can be reused as dilution water in a paper machine, or it can be passed to the waste water purification plant. The coagulation agents normally used for this purpose are based on highly cationic water soluble polymers, or multipositive metal ion solutions, or combinations of the two. This example demonstrates the manner in which the addition of the cationized cellulose removes the anionic colloidal material from the water. Subsequently, sedimentation of these ingredients is also improved by treatment with conventional chemicals. Waste water from a paper coating machine is taken fresh. By titration with a μTek PCD-02 titrator system, the charge, which was highly anionic, was measured. Also the turbidity and chemical oxygen demand were very high.

As a control, a sample treated with a standard precipitant (polyaluminium chloride (PAC)) was used which subsequently was flocculated with two types of a water-soluble polyacrylamide (anionic + cationic) Approximately 10% of cationized cellulose was added, based on the dry weight amount of the polyacrylamide, to the waste water sample, and mixed for a fixed time. Then the normally used amount of polyaluminium chloride was added, followed by the amount of polyacrylamine reduced by the weight of the aggregated cationized cellulose (= 90 percent of the standard amount). The waste water thus treated was poured into a calibrated measuring cylinder, and allowed to stand for 1 hour. Then the mud volume was measured. A smaller volume indicates a higher mud density, and therefore more convenient. Turbidity and chemical oxygen demand were also measured. Since this water would normally be reused as process water, or alternatively would be passed to the wastewater purification plant, low turbidity and chemical oxygen demand are an advantage.

Table 7 (Volume of sediment, turbulence and chemical oxygen demand) Surprisingly, the pretreatment of waste water with cationized cellulose, clearly improved sedimentation, turbidity, and chemical oxygen demand, over the levels obtained with the system standard. These positive properties were detected in combination with both cationic and anionic PAA. Example 36 Papermaking The cationized cellulose of Example 6 was shaken for 10 minutes as in Example 20, and diluted to a 3 percent suspension. This product was used in a laboratory test rig for paper retention systems, either as a substitute or as an additional component, thus producing several improvements to the papermaking process. Retention / Fixation A Britt jar drainage tester was used. Part 1) Application in a supply of fine paper free of wood. In the first part of this example, a supply of synthetic paper was prepared from a mixture of short and long whipped fibers free from wood, together with a ground calcium carbonate filler. This thick supply was diluted, salts were added to adjust the conductivity, and the pH was adjusted in neutral. The supply, when leaked, had a negative charge, due to dissolved or colloidally dissolved substances (anionic waste). This anionic charge is measured as the cationic demand, and results from the titration of an aliquot of the filtrate against a standardized cationic polymer (polyethyleneimine 0.001) in a particle charge detector, or using suitable color indicators, such as orthogonal blue. toluidine as an indicator of the end point. A series of drainage tests were carried out using different retention systems, and also replacing the individual components of these systems with the cationized cellulose explained above. These drainage tests were conducted with the pitcher stirrer Britt in operation. In tests that used cationized cellulose as part of the retention system, this component was added before the second component, a water soluble polymer. The second componerite was only added shortly before the beginning of the dehydration phase. Pitcher filtering Britt (A) was tested for the solids content, filtering through a non-ash filter paper, previously weighed, giving a second filtrate (B). The filter paper was filled with ashes to determine the retention content of the filler. The second filtrate (B) was tested by the chemical oxygen demand (DOQ), by the and by the residual anionic charge or the cationic demand, as described above. The results of this test series are shown in Table 8 Table 8 Part 2) Application in a supply containing ground wood / desiccant In the second part of the test series, a supply of paper was taken as the thick supply directly from a mixing front of a paper machine. This supply contained ground wood pulp, deinking pulp, a small amount of pulp fibers together with porcelain as a filler, and was diluted to a 1 percent consistency. The same test procedure as above was conducted on this supply. This time, a water-soluble polyethyleneimine was used as a standard retention aid for the Britt jar drainage tests. This polyethyleneimine, which is also the standard retention aid in the paper machine concerned, was partially replaced by cationized cellulose. The results of this test series are shown in Table 9 Table 9 The replacement of some of the water-soluble cationic polymer (either polyacrylamide, as in Example 1, or polyethylenimine with Example 2), by the cationized, water-insoluble whipped cellulose particles, produces a surprising and significant increase in retention of the fine substances, including the filler, and a reduced turbidity, a reduced chemical oxygen demand and anionicity, and consequently, a noticeable decrease in the anionic waste dissolved and colloidally dissolved in the second filtrate. These improvements are naturally of significant interest to the papermaking process. Dehydration Part 3) Application in a paper supply (free of wood, fine paper) In the second series, the Britt jar was equipped with a larger diameter drain pipe, allowing the drainage speed of the supply to be measured directly as a function of the supply, the auxiliary aggregates, and the sieve used. During this modified Pitcher Britt procedure, the filtrate was collected in a container placed on an electronic balance. The balance was programmed to send a signal of the recorded weight at set time intervals to a computer, in such a way that dehydration curves of the weight of the filtrate could be recorded against time. The results of these tests are shown in Table 10. The percentage of the retention / dehydration system refers to the dry weight of the retention aid on the dry weight of the paper supply.

Table 10 The replacement of some of the normally used water-soluble cationic polymer (in this case polyacrylamide) by cationized, water-insoluble cellulose particles produces a surprising and significant increase in the rate of dehydration for paper supply. This means that, when applied to a paper machine, the speed, and therefore the production of paper, can be increased.

Example 37 Cationized cellulose of Examples 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 25, and 31 was used as a partial replacement for a retention system of water-soluble polymer in papermaking, and the results were compared with each other. As a control, the polymer alone and a placebo were used, and a cellulose was also included which was prepared using the procedure of Example 7, but without adding cationizing agent. Each product was beaten for 10 minutes by the beating procedure of Example 20, and used as a 3 percent paste. The test procedure employed was the method of Example 36, Part 1. Each product was added in a standard concentration of 0.4 percent cationized cellulose with 0.2 percent water-soluble polyacrylamide as an auxiliary retention system. The paper supply was also the same as that of Example 36, Part 1.

The results are shown in Table 11.

Table 11 In this test, the retention rate was always higher with the use of cationized cellulose than with the polymer alone. This effect could not be detected with the use of non-cationized cellulose.

EXAMPLE 38 Paper Properties This example demonstrates that, by replacing part of the conventional retention systems with cationized cellulose, the strength of the paper sheet with a higher filler content can be maintained or improved. This is interesting, because a higher filler content usually reduces the strength of the paper. Paper sheets were made using a laboratory sheet former. The supply used was basically similar to that used in Example 36, Part 1, that is, a mixture of short and long fibers free of wood with calcium carbonate filler. The cationized cellulose used was that of Example 7, with poly-DAD AC as the cationizing agent, and 10 minutes of beating, as described in Example 20. A range of paper sheets were made using different retention systems, and part of these retention aids replaced by cationized cellulose as explained above.

Table 12 Example 39 Fixing agent for anionic waste in papermaking The product of Example 14, beaten for 10 minutes as described in Example 20, was used to treat a sample of paper fiber furnish of ground wood, for fix the anionic garbage. This supply, taken as a supply of approximately 4 percent directly from the input fiber stream to the paper machine, contained relatively high levels of anionic waste, such as soluble and colloidally soluble substances based on lignin that interfered with the papermaking process, especially the retention system. The efficiency of cationized cellulose was compared as a garbage trap, with inorganic cationic fixative agents (Ekokemi polyaluminum chloride), and water soluble organic cationic polymers (BASF Catiofast SL). It could also be demonstrated that an overdosage of conventional fixative agents can lead to overcationization of the water circuit of the paper machine, and therefore, also to adverse effects on retention. Cationized cellulose was added to 500 milliliters of the milled wood feed, and mixed for 5 minutes. The supply of ground wood thus treated was subsequently filtered through a black slat filter Schleicher &; Schüll 589 vacuum, and the filtrate was tested for turbidity, chemical oxygen demand, and cationic demand.

This anionic charge is measured as the cationic demand, and results from the titration of an aliquot of the filtrate against the standardized cationic polymer (polyethyleneimine 0.001 N) in a particle charge detector, using suitable dyes such as ortho-toluidine blue as an indicator of the end point. For the overcatalyzed filtering, a standardized anionic polymer solution (Na-PES 0.001 N) was used. From these first tests, the cationic demand for the supply of milled wood was calculated depending on the fixing agent used, and then twice the particular amount needed was added. The degree of overcathionization of the filtrate was measured by titration, and is expressed in the table as the negative cationic demand.

Table 13 The cationized cellulose of Example 14 exhibits a significant ability to fix the anionic waste, compared to conventional fixing agents, but has the advantage that, due to its insoluble nature in water, it does not lead to overcationization of the filtrate, as occurs with the addition of water soluble products. EXAMPLE 40 Dyeing behavior of cationic cellulose yarns In a dyebath with a concentration of 5 grams / liter of orange II, the cationized cellulose of the invention of Example 6 is dyed, or alternatively the non-cationized cellulose of the xanthogenate process. Yarns spun with 3 dtex were used. The proportion of the bath is 1: 6. The dyeing took place at room temperature for 30 minutes. After removing the spent bath, the rewash was performed with desalinated water and drying. Results of * the measurement: Whiteness Extermination ISO spent bath, L A B dilution 1: 100 Control value 0.3 Cellulose not cationized 1,732 15.40 71.96 +38.97 +42.73 Cationized cellulose 0.461 1.38 37.74 +5123 +44.58 Elrepho 2,000 for the measurement of the location of the whiteness / color Sample Preparation: The dry thread is rolled as evenly as possible on a cardboard strip 30 millimeters wide.

The thickness of the winding must be so high that no change in the value measured through the surface of the cardboard takes place. During the washings of the samples, it turns out that the fibrous material consisting of cationized cellulose, has a firmness of color much higher than the non-cationized quality.

Claims

NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, property is claimed as contained in the following: CLAIMS 1. Cellulose particles having cationic groups, characterized in that the cationic groups are present even inside the cellulose substance, the concentration of the cationic groups being constant or increasing from the outside to the inside, and at least one cationic group being present per 100 anhydroglucose units of the cellulose.
2. The cellulose particles according to claim 1, characterized in that the cationic groups inside the cellulose are immobilized.
3. Cellulose particles according to claim 1 in any of the preceding claims, characterized in that the cationic groups are covalently bonded to the cellulose.
4. The cellulose particles according to claim 1 in any of the preceding claims, characterized in that they have an average particle size of 0.001 to 10 millimeters, in particular 0.1 to 1 millimeter.
5. The cellulose particles according to claim 1 in any of the preceding claims, characterized in that they have an average particle size of 0.1 to 1 millimeter.
6. The cellulose particles according to claim 1 in any of the preceding claims, characterized in that the cellulose particles are present in combination with a water-soluble polymer.
7. The cellulose particles according to claim 6, characterized in that the cellulose particles are present in combination with a water-soluble cationic polymer.
8. The cellulose particles according to claim • in any of claims 6 or 7, characterized in that the cellulose particles are present in combination with polyacrylamide.
9. A method for producing the cellulose particles according to claim as claimed in any of the preceding claims, characterized in that the cellulose is reacted with a cationizing agent.
The method according to claim 9, characterized in that the cellulosic raw material used is unsubstituted pulp, a cellulose ester or ether, carboxymethylcellulose, hydroxyethylcellulose, and cellulose sulfate, cellulose acetate, chitosan, or cellulose. alkaline
11. The method according to claim as claimed in claim 9 or 10, characterized in that the reaction is carried out as a reaction of solids.
12. The method according to claim 11, characterized in that the cellulose used is alkaline cellulose which is kneaded to react with the cationizing agent.
The method according to claim 9 or claim 10, characterized in that the dissolved cellulose is mixed with a cationizing people, and the dissolved cationized cellulose is precipitated into cellulose particles.
14. The method according to claim claimed in any of claims 9 to 13, characterized in that the solvent used for the cellulose is N-methylmorpholine N-oxide, lithium chloride dimethylacetamide, and water in the case of the derivatives of cellulose soluble in water.
15. The method of compliance with the claim in any of. claims 9 to 14, characterized in that the cationizing agents used are aluminum salts, cationic polyelectrolytes, or reactive monomers.
16. The method according to claim 15, characterized in that the weight ratio of aluminum salts or cationic polyelectrolytes to cellulose is between 0.03: 1 and 1: 1.
17. The method according to claim 15, characterized in that the reactive monomers are reacted with the cellulose in a proportion such that the degree of substitution is not greater than 0.2.
18. The method of compliance with the claim in claim 15, characterized in that the aluminum salt used is polyaluminum chloride or an alkaline aluminate.
19. The method according to claim 15, characterized in that the cationic polyelectrolytes used are polydialkyldiallylammonium chloride, dicyandiamide, dicyandiamide condensate, polyamines, or ionenes.
20. The method according to claim 15, characterized in that the reactive monomers used are primary, secondary, or tertiary amines, or quaternary ammonium bases, each with at least one residue that reacts with an OH group. of cellulose.
21. The method of compliance with the claim in the claim. 20, characterized in that the reactive residue is a halogen, an epoxy group, or an imino group.
22. The method according to claim 21, characterized in that the reactive monomer is a trimethylammonium salt of 2-chloroethane, or a salt of propoxytrimethylammonium or a mixture thereof.
23. The method according to claim 13, characterized in that the dissolved cellulose, when mixed with the cationizing agent, is present in a concentration of 0.5 to 4 weight percent.
24. The method according to claim 13, characterized in that the dissolved cationic cellulose is regenerated in a precipitation bath.
25. The use of the cellulose particles according to claim as claimed in any of claims 1 to 8, in the manufacture of paper.
26. The use of cellulose particles according to claim 25, as a means for fixing the interfering substances in the paper, which are present in the water circuit during the manufacture of the paper.
27. The use of cellulose particles according to claim 25, as a means for retaining the fine substances in the paper during the manufacture of the paper.
28. The use of cellulose particles according to claim 25, to increase the strength of the paper during paper manufacture.
29. The use as claimed in any of claims 25 to 28, with the proviso that 0.1 to 10 kilograms of cellulose particles are used per tonne of paper supply (absolutely dry).
30. The use of the cellulose particles according to claim as claimed in any of claims 1 to 8, as a flocculant.
31. The use according to claim 30, as a flocculant for the purification of wastewater.
32. The use of the cellulose particles according to claim 1 in any of claims 1 to 8, characterized in that the cellulose particles are used in combination with a water-soluble polymer.
33. The use of the cellulose particles according to claim 32, characterized in that the cellulose particles are used in combination with a water-soluble cationic polymer.
34. The use of cellulose particles according to claim 32, characterized in that the cellulose particles are used in combination with polyacrylamide.
35. The use of cellulose particles as claimed in any of claims 32 to 34, characterized in that the cellulose particles are used in the drying of sludge in combination with a water soluble polymer, in an amount of 1 to 10 weight percent of the cellulose particles, based on the water soluble polymer.
36. The use of cellulose particles according to claim as claimed in any of claims 32 to 34, characterized in that the cellulose particles are used in papermaking, in combination with a water soluble polymer, in an amount of 40 to 60. percent by weight of cellulose particles, based on the water soluble polymer.