DE2115409A1 - Fillers - Google Patents

Description

Patent attorneys Dipl.-Ing. F. Weickmann,

Dipl.-Ing. H.Weickmann, Dipl.-Phys. Dr. K. Fincke Dipl.-Ing. F. A. Weickmann, Dipl.-Chem. B. Huber.

8 MUNICH 27, DEN

MÖHLSTRASSE 22, CALL NUMBER 48 3921/22

WELWYIi HALL RESEARCH ASSOCIATION, Welwyn, Hertfordshire / England Church. Street

Fillers

The invention relates to a method to produce mineral particles to be coated with coagulated compounds «The coated ones Mineral particles are used to improve the retention of a roll of paper tape. The invention relates to in particular the use of calcium carbonate. An essential feature of the present invention is in that the chemical reactivity of calcium carbonate in the presence of alum, which is used by the papermakers is decreased.

The use of calcium carbonate fillers as weighting agents or fillers in paper is advantageous because of the improved durability. If you use whiting chalk instead of the quinatone commonly used, there is a further advantage in economy. This is essentially due to the fact that practically all of the rock from a limestone quarry is in filler is transferred, whereas a large part of impurities such as silicon dioxide is thrown away from a clay pit must become. In England there is an additional advantage if you use whipped chalk instead of China clay as fillers ■ used that there is a sufficient supply for whiting chalk and that many whiting chalk manufacturing

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drives are conveniently located

However, the elaboration of methods to develop snake chalk as a paper filler has been greatly delayed by difficulties encountered using the traditional rosin-papermaker-alum screening methods in conventional paper-making processes. This process usually operates under acidic conditions which are impossible to maintain in the presence of suspended calcium carbonate particles. Although other sizing or Sieving methods are known such as those using alkyl ketene dimers ("Aquapel", trade name of Hercules Powder Co.), cationic polyamide emulsions ("Basoplast", trade name of BASP (UE)), and soluble carboxylated polymers ("Scripset ¹¹ , trade name of Monsanto Chemicals Ltd.) used as glue, all of these means individually have disadvantages.

It has been shown that under many milling conditions a Good gluing using calcium carbonate as a filler is achieved when using alum and severely unbound Resin emulsion adhesives such as Bewoid sold by Butler Malros Ltd. is used. During execution however, this method also has difficulties. In the paper industry it is common to have that Amount of alum added to a neck or stick is to be checked by its pH, i.e. its acidity or alkalinity, by determining it just before he on the wire of the Fourdrinler papermaking machine is directed. With calcium carbonate as a filler, the pH value is automatically buffered back to approximately 6.8, regardless of the amount of alum added, so this method can no longer be used. In addition, the papermakers have a tendency to add an excess of alum during the experiment.

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During paper manufacture, calcium sulfate collects in the circulating water of the paper machine, due to the reaction between the acidic alum and the calcium carbonate. This has drawbacks. The presence of sulfate ions is undesirable because the sulfate ions tend to destroy the sizing agents at neutral or slightly acidic pH values. The calcium ions also tend to react with a small amount of the sodium resin present in the Bewoid size. The calcium resin so formed has little or no sizing properties, and it is hydrophobic and tends to foam on the surface of the sheet as it is formed on the paper machine, thereby stabilizing air openings and creating air bubbles "dandy" Markings ¹ * or "wormholes" arise.

If soft water is used in the manufacture of paper that is not diverted (an open return water system), this is how cellulose pulp, which is a calcium carbonate filler, is glued If you use resin and alum for papermakers, it quickly contains and you get one Paper that has physical properties that are comparable are with those of a paper that was produced under similar conditions only with a clay filler. However, problems can still arise from foaming or from excessive use of alum.

However, in many paper mills it is not possible to carry out this process. Many mills use hard Water Others use a circulation system to keep water save, and use circulating water in the first pulper and as the first output water for the Rüfarbütte.

The present invention relates to a method for the production of fillers. The inventive method

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drive is characterized in that an aqueous suspension of mineral particles with at least one water-soluble inorganic or organic compound mixed and the compound coagulated in such a way that the mineral particles are coated with the inorganic or organic compound.

The term "making paper" as used in the present application includes all processes for the production of cardboard and non-woven jErzeugk nissen. The fillers are also used in cement production and other procedures useful. The invention also relates to a pulp material for making paper containing a product made by the above process. The subject of the invention is also a process for the production of paper in which the above-described filler material is used.

The preferred mineral particles for the process of the invention are calcium carbonate or whipped chalk particles. The invention is not limited to calcium carbonate, as other similar mineral materials such as calcium sulfate, titanium dioxide, china clay, calcium and W zinc sulfide can also be used as well as mixtures of these mineral materials.

Although calcium carbonate is mentioned in general as a filler in the following, it should be noted that the inventive The method also applies to other finely divided fillers mentioned above, and it can be advantageous be "filler-fibers" from other materials to aid retention, especially when a positive charge is required. Independent of general remarks »which are given later, the invention relates in particular to fillers made of calcium carbonate, which can be used in fiber fabrics that are sized.

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It is thus a great advantage that the implementation between acidic aluminum sulfate (papermaker's alum) and calcium carbonate, which is used as a filler will. Surprisingly, it has been found that this is possible using the process according to the invention. To that To carry out the method according to the invention, there are various possibilities.

The first method is to make the whipped chalk particles coated in an aqueous slurry with a water-soluble polymer, the slurry dries to obtain a filter cake, and this filter cake is disintegrated or ground, whereby particles are obtained a size that is suitable as a paper filler. Are such particles suspended in water and with When treated with acid, the reaction is much slower than with untreated calcium carbonate particles is · This can be recognized by the slow progression of the pH value from acidic to alkaline «It has been found that various forms of starch, in particular potato starch, are suitable for the process according to the invention, since they are cheap and water soluble. The starch surrounds the aggregates of calcium carbonate particles when dried are, as a partially soluble coating. Various substances to make it insoluble can be added before drying will.

Will such particles coated with starch for a long time Soaked in water, they tend to have some of their resistance to acid attack to lose * It is believed that the starch swells and that at least some of it dissolves in the water *

The production of, for example, starch-coated calcium ' carbonate particles can conveniently be added to the wet processes can be used in the production of natural whipped chalk. Sin filter cake with A solids content of around 80 ^ is that in this process

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usual intermediate. This is dried and then the dried cake is crushed. A starch solution in which the starch has been dissolved by heating can lead to this cake or the whiting chalk suspension before Filtration can be added. After drying, the filter cake is much harder than usual and you have to grind vigorously to obtain a suitable particle size, which is suitable for the particles to be used as a paper filler. These extra procedures increase the cost of the end product,

A second method of coating calcium carbonate particles in water uses the phenomenon known as retrogradation of strength is known. Starch is dissolved in water by making a stirred aqueous suspension of Starch grains heated until the grains burst. With a suitable concentration it changes the viscous, opalescent Gradually dissolve into a gel structure, this phenomenon being irreversible. A suspension of whiting chalk in starch solution is subject to this change, Au3 der For example, U.S. Patent 2,140,394 is known to a suspension of clay particles in a starch solution that had been left to stand and which had become stiff in the process (retrograded), can be dispersed in water, whereby particles are obtained that are surrounded by swollen, retrograded strength, i.e. degenerate strength. It was now found that such a suspension of calcium carbonate particles had a significantly lower activity against it Acid shows up as an aqueous suspension of untreated Calcium carbonate particles.

A difficulty with this process is that the heterograde process is so slow that it is almost runs uneconomically. Its speed can be increased by varying the temperature. Cold storage has been found to be useful.

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It is known that the retrogradation phenomenon is associated with only one component of starch, namely the amylose component. Natural strengths therefore differ in the rate at which the solutions retrograde for this and other reasons. In general, raw starch or untreated starch retrograde much faster than starches that have been subjected to oxidation, depolymerization, or other treatments. However, starches are also available which have increased amylose content. However, these starches are difficult to solve and it may be necessary ^{to heat them at 120 °} C. in an autoclave. A mixture of starch and filler particles in the autoclave undergoes retrogradation more quickly than the usual raw starches, and the inconveniences which, as mentioned above, occur due to the time factor, are thereby reduced. However, the need to use an autoclave to dissolve the starch is disadvantageous with this method.

A third, preferred method of carrying out the present The invention consists in forming a suspension of calcium carbonate particles in water and a solution to a broken, precipitable connection. The failure of the connection is carried out by known methods such as by salting out or by adding a metal salt, adding a solution of an incompatible polymer, the precipitation causes the formation of an insoluble compound with a metallic salt, dilution below the solubility point of the compound or compound mixtures, addition of a water-miscible liquid, which is not a solvent for the compound, adding a solvent that is made up of the molecules of the compound Removes water, causes. One can also see the interaction between two types of polymer through hydrogen bonds use, where precipitation occurs. Examples of

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■ - 8 -

Compounds of this type which can be used are starches, especially potato starches and oxidized or anionic starches, polymers which form insoluble metal salts such as sodium alginate, citric acid castor oil, maleic linseed oil, acidic alkyd resins, milk casein, Irish moss, gum arabic .., gelatin, albumin , Alginates, casein, agar-agar, pectins, carboxymethyl cellulose and other carboxylated cellulose compounds and one or more different kinds of synthetic copolymers containing such monomers as acrylic acid or maleic anhydride, or synthetic copolymers having carboxy groups. These copolymers ψ are usually produced by emulsion polymerization, an emulsion or a latex of the acidic polymeric material being obtained.

For example, polymers or copolymers which contain darboxy groups and which are in Solution can be used (specific examples of these are: soluble polymers or copolymers of acrylic emulsions made by Rohm & Haas Ltd. getting produced). When adding alkali (sodium hydroxide or ammonium hydroxide) a clear solution or a clear gel of the polymer is obtained. Also valuable are the fatty acid soaps and the polymeric fatty acid soaps.

Other compounds that can be used are magnesium hydrogen carbonate « Sodium silicate, sodium aluminate and hydrogen fluoride.

The various types of compounds can be used alone or as mixtures. With most of the invention Applications are the connections alone or together with a second or a third connection used.

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The preferred types of compounds that are valuable are sodium alginate, starch in oxidized or anionic Form, a mixture of starch in any of its forms and sodium alginate, a fatty acid soap or a fatty acid polymer soap, for example sodium oleate, gases, fully hydrolyzed polyvinyl alcohol and a mixture of sodium alginate, casein made soluble with ammonia, and acrylic emulsions made soluble with ammonia in Form were transferred.

A sodium salt of a carboxylated high molecular weight compound is preferred because of, for example, the precipitation with alum causes an aggregate of the filler, which is coated with the insoluble polymer, and wherein a positive charge occurs. This is valuable because of the property's positively charged aggregates in the paper product have that they result in good prayers.

The preferred precipitating agents that can be used to precipitate the polymers are salts of polyvalent ones Metals (where "polyvalent" means that the metals have a valence of 2 or more) or compounds, containing polyvalent metals. Particular examples of these salts are aluminum sulfate (alum des Paper makers), calcium chloride and borax (sodium tetraborate). It should be noted, however, that many others Polyvalent metal salts can be used, as well as other materials that are polyvalent in aqueous solution Form metal ions »

The use of a trivalent or tetravalent metal salt solution such as aluminum sulfate is preferred as the precipitated aggregates of calcium carbonate or other fillers receive a positive charge and therefore have a greater tendency to get along with the cellulose fiber in dry conditions To join paper,

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- ίο -

Hard water can also act as a precipitant. Was the calcium carbonate suspension with an organic High molecular weight material made in distilled water and added to hard water can do so may be sufficient to cause the polymeric material to become insoluble, with the filler particles interfering with the insoluble material. Special combinations of precipitating agents and the agent that precipitated to be useful in the present invention are sodium alginate, starch and sodium alginate or oxidized or anionic starch with a soap of a fatty acid or a polymeric fatty acid soap, all of which are precipitated by aluminum sulfate or calcium chloride, casein precipitated by aluminum sulfate, ■ fully hydrolyzed polyvinyl alcohol, precipitated by Borax, casein made soluble with ammonia, and acrylic emulsions made soluble with ammonia. were precipitated together with sodium alginate solution by calcium or aluminum ions.

The precipitation from an aqueous starch solution and a compound that has a carboxy group or groups contains like sodium oleate there is a particularly synergistic effect between the starch and the sodium oleate, if "So that calcium carbonate particles are coated. The formation of flakes of starch-Schlärara chalk not only occurs with fatty acid compounds but also with starch and many other compounds that are soluble with alkali can be made on when implemented with alum.

In the simplest application of the method according to the invention, a water-soluble polymer becomes the calcium carbonate suspension added before this filler slurry to the stick or to the approach in the paper machine is given. It is important that the adsorbable polymer be added to the filler slurry

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takes place under suitable conditions and preferably with a later addition of precipitants such as alum, see above that the polymer is fixed on the filler particles. " The approach can already contain resin-alum precipitates or polymers, and further alum addition can be done later.

Calcium carbonate is slurried with water before it is used, and it is preferred that deionized water be used in the slurry, although not is essential. Natural water is also suitable. The deflocculation of a concentrated aqueous slurry of filler is obtained through the use of anionic surfactants or other surfactants Funds made easier. Particularly suitable for this purpose are Calgon A (a sodium polyphosphate made by Albright & Wilson Ltd. manufactured) and Dispex N.40 (a sodium polymethacrylate, that of Allied Colloids Ltd. is produced), using such proportions that the suspension has a rheologically dilatant or shear thickener character before polymer solution is added.

The water-soluble polymer can be made using deionized Dissolved in water. As indicated above, it is also preferred that the calcium carbonate be in deionized Water is slurried. The slurry and the solution are mixed and then controlled Rate added to a dilute solution of salts which precipitate or become insoluble with good mixing cause. Of course, the solution of the insolubilizing salts can be a part of the paper base i.e. the paper approach is passed, beaten, and otherwise treated as part of the usual Making the stick in papermaking. During the manufacture of the stick or the approach, alum becomes or another soluble polyvalent metal salt to the

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Stock admitted. When the slurry and the solution of the water-soluble polymer to the solution of the polyvalent Metal salt are added, aggregates of precipitated polymer and calcium carbonate particles are formed. the The size and shape of the aggregates formed depends on the proportion of particles, the precipitable polymer and the Water that is added to the suspension, and the Shear rate and / or turbulence at the time of mixing. Under optimal conditions, aggregates formed with essentially fibrous properties. This has advantages as one in the paper product good retention and the; Strength of wet and dry paper product is improved. The precipitation of a hydrophilic polymers at a suitable pH value give a suspension which forms fibers when drawn out. if for example, a small amount of the suspension is placed between two glass plates that are in intimate contact with one another stand, there and pull the glass plates apart, long strings of so-called "filler fibers" are formed. If the pulling out is brought about by the action of shear forces, flakes with a fibrous structure form in the solution Character (filler-fiber-flakes).

_φ 1

A process for the preparation of such "filler fibers"% is that shear forces can act on the Füllstoffsuspensioh in the polymer solution as it is added to the solution of the precipitating agent. The shear forces are applied by adding a thin stream of the particle suspension and the solution with the surfactant and added polymer solution, as described above, into a solution of precipitant under suitable conditions of shear force effects such as vigorous, non-turbulent stirring.

The filler-fiber flakes are placed in the paper stock, and the product is manufactured by well-known paper manufacturers

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process. When heating, i.e. during the When the paper product dries on the paper machine, bonding with the fiber occurs.

When adding sulfuric acid or (acidic) alum the Papermaker to a suspension of coated aggregates, from calcium carbonate particles immediately becomes an acidic Solution formed. This remains for a remarkably long time and only falls slowly to a pH value of 6 instead of a pH value of 7 back. With an untreated suspension of whiting chalk occurs faster Change of pH value with formation of carbon dioxide. The difference between the pH 6.0 and 7 »0 is enough to make the sizing process with resin and alum much easier on the papermaking machines. The pH of the stick can still be used by the papermaker to determine the speed of the Regulate alum addition. The rate of formation of calcium ions at a certain pH becomes strong so that various troubles mentioned above are not observed. It is also possible to run the machine with a moist product on the wire of the pourdrinier at a pH closer to 6.0 is more than possible to operate with untreated slurry circle filler. It is known that This is the manufacturing difficulty when gluing, the bubble balloons, the deposition of the material on the wire, the paper transport towels and the drying rollers and blinding of the paper drying tissues are reduced.

Natural. Mud Circles contains a specific one in particular Proportion of particles that are unnecessarily fine to fill paper. It has been found that more economical papers can be produced without using these fine particles. This usually requires a classification procedure, whereby the fine product is economically valuable

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is full and the larger particles are used as weighting agents can be used for paper. If the chalk particles are covered in the form of aggregates, this <driving is no longer necessary. This way you can get a common whipping chalk and unexpectedly high. Load values: Use papers with good opacity and maintains strength. Since whiting chalk is a low-cost component of paper, papers, which contain whiting chalk are very competitive in terms of the cost of the raw materials.

fc The use of other water soluble or water dispersible Polymeric in the papermaking stick for special papers such as those with improved wire retention is also not excluded.

The process according to the invention can be carried out during the production of the calcium carbonate particles, so that Calcium carbonate particles with reduced chemical reactivity are supplied to the papermaker. Alternatively the method according to the invention can be carried out even within a paper mill during the manufacture of the stick will.' Furthermore, it is possible to dry the calcium carbonate particles after they have been treated with various combination " nations of high molecular weight organic compounds have been coated, depending on the requirement the paper maker.

The insoluble, coated particles are adhesively bonded to one another to a considerable extent, and they can become one have a greater tendency to bond with the cellulosic fibers in the dried paper than uncoated ones Particles, the strength properties (tensile strength and in particular tear strength) are in paper that is coated with Particle made was improved as compared to paper made without coated particles.

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The following examples illustrate the invention without, however, restricting it. Although in all examples as Mineral particles calcium carbonate was used, the inventive method is applied to any other mineral filler applicable because the organic material only forms a coating around the particles and does not react with them.

example 1

This example shows in a laboratory test that the speed, with which natural whitewashing chalk is attacked by acid alum, reduced by appropriate treatment can be.

A $ 1 (w / w) suspension of BWF Grade 4-0 natural whipped chalk was made in distilled water. 500 ml of the suspension was continuously stirred with a magnetic stirrer in a beaker and the pH of the water (usually between 8 and 9) was determined with a pH meter using a glass electrode. A solution of 5 »Seigern iron-free alum for papermakers (Al ₂ (SO.), 18H ₂ O) in distilled water was added in such an amount that the pH was adjusted to 7» 0 and remained constant for at least 1 minute. Another 20 ml of 5.5% alum solution was quickly added from a beaker. The pH dropped (the water became more acidic) and then rose again. The rate at which the pH value dropped towards alkalinity (high pH value) was a measure of the reactivity of the untreated whiting chalk towards acid.

Concentrated suspensions of the whiting chalk were made and then solutions of precipitable compounds were made added, the concentration being chosen so that 5 parts w / w. solid polymer per 100 parts Mud chalk received. Suspensions in distilled

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Water containing $ 1 solid whiting was made and as examined above. Solutions of the polymers were made with and without heat after addition of alkali according to known methods Process made.

The whiting chalk was treated in aqueous suspension with the polymer solution, the water was evaporated and the mass was crushed to give particles. The treated dry whitewashed chalk was tested as above.

The pH after 3 minutes after the addition of 20 ral alum solution · Shows sufficient protective effect of the various polymers in whiting chalk against attack.

Studies to evaluate the effects of various treatments in treating OaCO ^ particles against attack

Determine acidity

Treatment material parts w / w Treatment- pH

Solids / 100 proceed according to Parts of slurry - 3 min.

chalk

Comparative experiment

- no treatment - - 6.5

anionic starch

Stadex 740 (Starch
Products Ltd.) 5 dried 6.2

Sodium alginate

(P1002 alginates

Industries Ltd.) 5 "6.1

Sodium silicate

(Pyramid 8-cros-

fields Ltd.) 5. "6.4

Sodium Resin 5 "6.3

Stearic acid 2 dry treatment 6.1

Magnesium hydrogen

carbonate 5 dried 6.4

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Polyvinyl acrylate (Vinacryl 7170 vinyl

Products Ltd .; 4, 5 Sodium alginate
(as above) 4, 5 anionic starch
(as above) O, 5 anionic starch /
Sodium alginate 5 / 0.5 H ti 8 / 0.2 oleic acid / Lissopol
NX (ICI Ltd.) 75 / 0.75 Oleic acid 5

Polyvinyl alcohol (Gohsenol 26, British Trades and Shippers Ltd.)

Polyox WSR 301 / Dispex N40 (Union Carbide) Allied Colloids

4.6 / 0.4

Sodium silicate / sodium aluminate, neutralized with sulfuric acid 2.5 / 2.5

Sodium silicate / alum for paper production 2.5 / 2.5

Hydrogen fluoride

hydrolyzed keratin

(Foam compound

Pyrene)

Primal ASE-95 Lennig Chemicals, made soluble with ammonia

Milk casein made soluble with borax / ammonia

Special hide glue J9 / 645 (Croda Polymers / Pormaldehyd)

Potato Acid / Myatolene KK7 (zircon mixture, Catomance Ltd.)

1.5

dried Aufschi. 6.3 damp Il 6.0 η ti 6.1 fl Il 5.8 Il It 6.2 ti Il 6.3 η It 6.2 . Il Il 6.3 Il 6.4

If

M.
Il

6.1

6.3 6.3

6.5

6.2 6.2

6.1

6.4

neutralized with a solution of alum for papermaking before drying

1 (H) 8 4 S / 1 61 U

example

Am experiment on the mill was carried out in one Paper mill for fine paper using a specially manufactured "protected whipping chalk", wherein a Printing paper was made for all purposes. The protected whitewash chalk was made by making a natural whipping chalk BWF quality 40 used as the slurry and 4 parts / 100 parts by weight of anionic starch Stadex 740 (Starch Products Ltd.) added and dried. The paper was made on a machine that uses * was operated at a speed of 69 m / min (250 ft / minute) using pulp that was $ 70 bleached Hardwood sulfate, $ 15 semi-bleached softwood sulfate, Contained 15 $ bleached softwood sulfate. The weighting material Contained $ 4 titanium dioxide plus extender and enough whiting to make a total filler salary of $ 14 received in the paper. The mixture of protected whiting chalk was slurried in water and added to the mixing tower with enough alum to give a pH of 7> 3. Right in front of the More alum was added to the distribution box to give the wire a pH of 6.8 *

"The results of this experiment showed the effect of the protective procedure as follows:

a) The additive was slightly reduced,

b) the sizing or sieving effect was improved, the resin addition was reduced from $ 0.9 to $ 0.6 during the Trial reduced without loss of sizing effectiveness,

c) excellent filler retention (60 to on the first pass compared to results obtained previously with untreated whiting chalk from 45 to 1

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d) Strength remained with improved stress retention obtain.

Example 3

A second experiment was carried out in a fine paper mill A, using 85 g of wood-free, smooth lithographic printing paper using a specially made "protected whitewash" chalk. The protected White chalk was made from 100 parts BWF grade 40 chalk, 4 parts Stadex 740 and 0.4 parts sodium alginate (P1002) prepared in a slurry and then dried. That, paper was at a speed made from a pulp batch of 72 m / min (240 ft / min), the $ 30 faen grade, $ 30 semi-bleached softwood sulfate and Contained $ 40 eucalyptus and enough whipping chalk to to give a total filler content of $ 14. The results of this attempt were the following:

a) The protective effect against acid was clear from the low pH values obtained (6.1) and one 50% reduction in the usual amount of alum required to make the system neutral;

b) Foam, bubbles or other problems did not occur in sheet formation;

c) the addition of glue v / was reduced from 0.9 to 0.6 $ during the experiment, although one achieved good gluing;

d) improved overall retention of fillers was reached, one received $ 93, compared to the usual value of $ 85 J

e) the sheet strength was retained despite a higher filler content compared to a sheet, made from the same batch before adding the "treated whitewash".

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example

The third example was carried out in a paper machine, which was operated at a speed of 105 m / min (550 ft / min) using conventional imitation art paper manufactured. Usually China clay is used as a filler.-This was completely through protected whitewash chalk replaced. The protected whiting chalk was produced as in Example 3. The protected Whiting chalk was previously slurried in alum, whereby a pH of 7-3 was obtained. This slurry was added to the pulp chest and just before the distribution box more alum was added.

Results:

a) With a material of 120 g, the surface wax pick increased from 4 to 9, whereby the Dennison wax test was used to measure;

b) the ink penetration time, determined with the Albricht measuring device, was increased from 60 seconds Increased 625 seconds;

"c) the total retention of filler in the paper was above $ 90;

d) The load on the paper was from $ 18 to $ 25 increased without loss of tear strength;

e) There were no problems such as "dandy bubbles", foaming, etc. on the machine.

Ex iel 5

A fourth experiment was carried out using a paper machine used and manufactured Faengraä book vellum paper, the fiber base being $ 70 Faengrass and $ 30 wood-free, contained broke weighted with clay. The machine speed was 69 m / min (230 ft / min) and

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protected Schlänimkkreis completely replaced the Chinese tone, which is commonly used as a filler. The protected whipping chalk was prepared as in Example 3. It was slurried with no alum added. The filler u. the alum were combined in a fine continuous stream just before the distribution box. The pH in the distribution box was 6.7 to 6.8.

Results:

a) At the beginning of the experiment, the material increased from 77 1/2 to 103 g, due to the very high retention the protected whitewash chalk;

b) the opacity increased from 92 to 96;

c) the Cobb test was during the entire machine test 17;

d) the weight in the paper was increased from $ 12 to $ 23 without any loss in paper strength ;

e) the surface pick was constant at 12/14;

* f) The experiment was terminated without any trouble on the machine and foaming or forming of dandy bubbles was not observed.

Example 6

Paper was made from a bleached sulfite batch (45 g weight basis) produced on a paper machine in a pilot plant.

The protected whitewash chalk was made as follows: 500 g of milk casein (corresponding to a sieve with a mesh size of 0.25 mm - 60 mesh) was over Wakes soaked in 5 1 water. This was added while stirring 250 ecm of the above sodium hydroxide and let the mixture

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again stand above the field. Live steam was introduced, causing the casein to dissolve. 500 g 10 # ASE-95 (Lennig Chemicals) were with 250 ml 10bigem sodium hydroxide and 4250 ml of water mixed and soaked over! The whiting chalk slurry was made from 20 kg of water and 28 kg of lime whitewash chalk grade 40 made and mixed with a hard stick. This mixture was left over Standing at night. The above liquid was removed leaving a slurry having a solids content owned by $ 71. 300 g of Calgon S were dissolved in 3 1 V / water. The ingredients were in the following order mixed and in the following quantities! 10 kg slurry, 100 g calcon solution, 2500 g hot casein solution and 480 g ASE solution.

The suspension was added to the steam of a turbulent mixing chamber along with alum. The basis weight of the paper increased to 150 g and the machine worked without interruptions. The filler appeared to be more fibrous in shape To be present.

Example 7

The mud circles were treated as in Example 6 to one to produce protected whitewash chalk.

A polyethylene bucket was half filled with 5 liters of distilled water and this was filled with 10% alum solution for the papermaking adjusted to a pH of 4.0. A fast stirrer was used to make a good strudel to create. The above suspension was added to the end of this vortex in a very thin stream. It formed fibrous flakes or fibers and the polymer became insoluble, so that these. not broke. It was It is important that the suspension stream was added continuously and uninterrupted to the alum solution.

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Microscopic examination showed that the flakes or fibrous aggregates similar in their dimensions were those of the little whipped, bleached sulfite paper pulp O

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Claims (12)

- 24 claims 1. A method of making fillers for paper, paperboard and similar products by forming a aqueous suspension of mineral particles and mixing the suspension of mineral particles with a water-soluble one Compound, characterized in that the water-soluble compound is present in the presence of the mineral particles is coagulated in such a way that the rope with the coagulated, water-soluble compound are coated. 2. The method according to claim 1, characterized in that the water-soluble "compound by drying the mixture is coagulated by water-soluble compound and mineral particles, so that a coating of the coagulated, water-soluble compound is formed. 3. The method according to claim 1, characterized in, that the water-soluble compound is coagulated by precipitation in the presence of the mineral particles. 4. The method according to claim 3 »characterized in that that the water-soluble compound is precipitated by a polyvalent metal cation. 5. The method according to claim 4, characterized in that the polyvalent metal cation is a calcium or an aluminum cation . 6. The method according to claim 3, characterized in that the water-soluble compound by borax is precipitated. 7. The method according to any one of claims 3 to 6, characterized in that a mixture of the aqueous sus- 1 0 9 8 4 5 1Λ 6? /, pension of the mineral particles and the water-soluble compound is added to a solution of the precipitant under turbulence. 8. The method according to claim 7, characterized in that the mixture of the aqueous suspension of mineral particles and water soluble compound added as a continuous stream to a turbulent solution of the precipitant will. 9. The method according to claim 2 to 8, characterized in that the precipitating agent is in solution in the stick or approach for the papermaking process is available. 10. The method according to any one of claims 2 to 9 »characterized in that the precipitating agent to the Ansata for the papermaking process in a continuous stream together with the aqueous suspension of the Mineral particles and the water-soluble material is given. 11. The method according to any one of the preceding claims, characterized in that the mineral particles calcium sulfate, ! Titanium dioxide, China clay, zinc sulfide or calcium carbonate or mixtures thereof. 12. The method according to any one of the preceding claims, characterized in that the water-soluble compound Starch, ITodium alginate, casein, a fatty acid soap, a polymeric fatty acid soap, fully hydrolyzed polyvinyl alcohol, or mixtures thereof. 109845/163 *