The sol of silicic acid and method for producing paper

 

(57) Abstract:

The invention relates to solu silicic acid and method for producing paper using this Sol. The silicic acid Sol has a content of disperse phase SiO2corresponding to the S-value in the range from 15 to 40%, preferably from 15 to 35% and contains particles of SiO2modified or unmodified alumina with a specific surface area of from 300 to 700 m2/g, preferably from 400 to 650 m2/, the Method of producing paper according to the invention consists of adding to the pulp of cellulose containing fibers, polymer and anionic Zola silicate, followed by forming and dewatering the obtained slurry on the grid. As the polymer charge cationic, for example, based on acrylamide or amphoteric polymer. The method uses a silicic acid Sol having a content of disperse phase SiO2corresponding to the S-value in the range from 15 to 40% and containing modified or unmodified aluminum particles of SiO2having a specific surface area of from 300 to 700 m2/year, mainly from 400 to 650 m2/, as the polymer used pulp pulp containing the filler. These sols give a significant effect on the tion applies to the new silicic acid sols, the appropriate way to obtain sols and application of new sols in paper production. More specifically the invention relates to new colloidal solution of silicic acid, which particles have a specific surface area and which have a comparatively high content of so-called microgel. New sols, in particular, are suitable for use as additives in combination with polymers and paper production.

Silicic acid sols, the term used here for Hydrosol of silicon dioxide, are water systems with very small particles of silicon dioxide, which have found application in a number of areas, which among other things depends on the particle size. In the last few years sols on the basis of silicon dioxide with a very small anionic colloidal particles of silicon dioxide have found increasing use in the manufacture of paper. Silicic acid sols are used as additives to the mixture in combination with the cathode or amphoteric, mainly to improve retention and dewatering in paper production.

Known combination of silicic acid sols with particles of at least the surface of which contain aluminum, and the Oia have a specific surface area ranging from 50 to 1000 m2/, Sols, which are used in serial paper production, are the sols of this type, which have discrete colloidal particles with a particle size of usually about 4-7 nm, i.e., a specific surface area of from about 700 to about 300 m2/g, and mainly commercially used sols with particles having a specific surface area of about 500 m2/, it is Usually assumed that sols with particles above a specified size give the best results, and they are also preferred from the viewpoint of stability. The aim is the creation of a colloidal solution of silicic acid how can monodisperse, i.e. that particles of the colloidal solution were discrete and non-aggregated and had how can a narrow particle size distribution. Upon receipt of the sols thus tend to avoid aggregation, i.e. the formation of microgel. Known silicate with some degree of education of the microgel. These sols made on the basis of particles with very high surface area and have found, in particular, the use in combination with the polymers in the manufacture of paper. Sols are colloidal solution-based particles with a very high specific surface 75 1000 m2/g, preferably 800 to 950 m2/g, and the particles are povernei with the invention installed, that sols based on silica particles, i.e. particles based on SiO2which have a specific surface area in the range of 300-700 m2and which have a comparatively high content of microgel, give a very good effect on retention and dewatering in paper production. In particular, it was found that sols with particles of a given specific surface area and the content of the microgel according to the invention give quite superior effect when they are used in combination with cationic polymers based on acrylamide, compared to previously used by the sols based on SiO2with a specific surface area in the same interval, which mainly contain discrete particles. The content of the microgel or unit may concentrate in the preparation of the sols.

The invention thus relates to new silicic acid sols, as further defined in the claims, and also relates to a method for producing paper from wood pulp cellulose.

New sols are different in that they have a high content of microgel, i.e., low S-value, and the fact that the particles Zola have a specific surface area ranging from 300 to 700 m2/, This specific surface area is determined ASS="ptx2">

Specific surface area is, accordingly, amounts to 400-650 m2/,

In contrast to known industrial sols with a specified specific surface area, which are used in paper production, sols according to the invention have a relatively high content of microgel and consequently, low S-value. It is assumed that the microgel, the aggregates are sufficiently in the form of two - or three-dimensional structures, more or less oblicovochnykh formations of aggregated primary particles. S-is for these nuclei is in the range from 15 to 40% by weight, and preferably, the S-value is 15-35% This S-value is measured and calculated in accordance with the technique described by Aileron R. K. and Deltaport R. D. I. Phys. Chem. 60, (1956) 955-957.

S-value can be viewed as a measure of the degree of education of aggregate or microgel, and low S-value indicates a higher content of microgel and can be considered as a measure of SiO2the content of the dispersed phase in the processes of mass.

Particles in these sols can be non-modified particles of silicon dioxide or particles of silicon dioxide or particles of SiO2the surface of which is modified is I. For particles modified with aluminum, they can be modified to level 2 25% is suitable from 3 to 20% Degree of modification of aluminium means the part of the aluminum atoms, which are bonded to the silicon atoms on the surface of the particles. The degree of modification of aluminum is given in percent and is calculated on the basis of 8 silanol groups per 1 nm2. This technique is described by Aileron in the Journal of Colloidal and Interface Science, 55 (1976): 1,25-34. These sols, respectively, have a dry residue, calculated as SiO2from about 3 to about 4% by weight, and the dry residue, preferably, ranges from about 5 to about 30% by weight.

It is established that these new sols which contain anionic particles are used in the manufacture of paper and similar products, and that they are here in combination with cationic polymers provide a very significant improvement in retention and dehydration. In particular, it was found that the new sols according to the invention containing unmodified aluminum particles, provide a significant improvement when used in combination with cationic polymers based on acrylamide, compared to the commercially used such sols, which are particles of the same size, but the particles kotoula of the invention, the present invention relates also to method of obtaining new silicic acid sols and application of colloidal solution as claimed in the attached claims.

The invention also relates to a process for the preparation of colloidal solution of silicic acid, which have a relatively low S-values, and which have a specific surface area ranging from 300 to 700 m2/, According to the invention silicic acid sols derived from traditional alkaline water glass, potassium or sodium water glass, preferably sodium liquid glass. The molar ratio of SiO2to Na2O or K2O, where Na2O and K2O in the following are given as M2O in liquid glass, as you know, are in the range from 5.5:1 to 4.5:1 and preferably in the range from 2.5: 1 to 3.9:1. Use a diluted solution of liquid glass, which, respectively, has the content of SiO2in the range from about 3 to about 12% by weight, preferably from about 5 to about 10% by weight. The solution of liquid glass, which usually has a pH of about 13 or above 13, acidified to pH from about 1 to about 4. The acidification can be carried out in a known manner by addition of mineral acids, such as, for example, sulfuric acid, chlorothalidone liquid glass, such as ammonium sulfate and carbon dioxide. Adding mineral acid acidification is performed in two stages, the first stage up to about pH 8 to 9, and then has some maturation, i.e. the growth of the particles, prior to further connect to a pH of from about 1 to about 4. However, it is preferable that the acidification was carried out using acid kationoobmennikom, the second inter alia, provide a more stable products and almost free from sodium acid sols. Acidification is preferably carried out using a strongly acidic cation-exchange resins, for example, sulfoxylates type. Acidification is preferably to a pH of from about 2.0 to 4, and most preferably from about 2.2 to about a 3.0. Obtained after acidification of acid Sol then podslushivaet. Alkalization is performed in a traditional alkali such as sodium hydroxide, potassium or ammonium. Preferably, the alkalinization was carried out by adding liquid glass. At this stage of alkalizing use potassium and sodium silicate, in particular sodium water glass with the specified molar ratio of SiO2and M2O. Used for alkalizing the solution of liquid glass have Asse. Alkalization is performed to pH not less than 7 and is suitable to pH in the range from 7.5 to 9. Alkalization is then performed to certainly molar relationship SiO2and M2O in the range from about 20:1 to about 75:1, suitable, in the range from about 30:1 to about 60:1. Upon receipt of Zola, as indicated above, the content of microgel can be influenced in several ways and to adjust it to the desired low value. The content of microgel can be affected by salt, regulation of condensation upon receipt sour Zola and when alkalization, because at this stage the content of the microgel depends on when will be the minimum stability for Zola at a pH of about 5. By the time of the passage of the contents of the microgel may be directed to the desired value. It is particularly convenient to control the content of microgel regulation of the solids content of SiO2when alkalization, therefore, a higher dry residue gives a lower S-value. In maintaining the content of SiO2when alkalinization in the range from 7.5 to 5% by weight of S-value can be adjusted to the values specified 15 40% Another suitable way of controlling the content of the microgel is to regulate podsolic the S-values to lower values at lower pH. To obtain sols with S-values in the range of 15 to 40% pH during alkalization, respectively, is adjustable from 7.5 to 8.5. When alkalinization in this pH interval suitable content of SiO2is in the range from about 5 to about 6% by weight. Acidic Sol has particles with a specific surface area above 1000 m2/g and usually at around 1300 m2/, After alkalizing begins the growth of the particles and therefore the decrease of the specific surface. After alkalizing the growth process is carried out so as to obtain the desired specific surface area. The desired reduction of the specific surface of between 300 and 700 m2/g can be obtained by heat treatment. When the heat treatment time and temperature are regulated so that less time is used at a higher temperature. From a practical point of view, heat treatment is usable at temperatures up to approximately 95oC for from about 1.5 to 24 hours When it is desired particle specific surface, if necessary, is carried out surface modification of aluminium in order to obtain particles that have the best charging stability in the acidic environment compared to non-modified particles. Modification is Modific sodium. Modification of the aluminum surface of the particles is carried out in a known manner and, as shown above, is carried out to the extent modification of their surface from 2 to 25%, in particular from 3 to 20% In accordance with the present method, after optional concentration can be obtained silicic acid sols with a dry content of from about 3 to about 40% by weight, the resulting sols have very good storage stability, i.e. they can be stored for several months without a significant reduction in specific surface area and without gelation.

New sols according to the invention are in particular suitable for use in paper production. The present invention relates also to this use of the sols. As stated in the introduction, a well-known application in the manufacture of paper sols based on SiO2in combination with cationic polymers, primarily in order to obtain improved retention and dehydration. These silicic acid sols are used in the same manner as previously known for sols acid with an anionic particles, and they give in combination with cationic polymers and amorphous polymers significant improvement in retention and dewatering in producing the CLASS="ptx2">

Sols can be used with positive effect in paper production over the whole range of pH from 4 to 10. Improved dehydration also leads to the fact that it can be increased the speed of the paper machine and in addition, you must remove less water on parts of the cake and drying machine, and thus is implemented significantly economically superior method of obtaining paper. Especially it should be noted significantly improved the effect of these sols with low S-values in comparison with the corresponding sols of high S-values when they are used in combination with cationic polymers based on acrylamide.

The invention relates also to a method for producing paper with the characteristics defined in the claims. Cationic or amphoteric polymers can be natural, i.e. on the basis of carbohydrates, or synthetic. As examples of suitable polymers can be shown cationic and amphoteric starch, cationic and amphoteric to Garga, cationic and amphoteric polymers based on acrylamide, cationic polyethylenimine and poly (diallyldimethylammoniumchloride). The polymers can be used alone or in combination with each other. Cationic polymers on SS="ptx2">

The number of Zola silicate and polymer in the manufacture of paper according to the invention can vary within wide limits, depending on the type of mixture, the presence of fillers and other conditions. Fit is the number Zola least 0.01 kg/ton, calculated as SiO2on dry fibers and optional fillers and suitable in the range from 0.05 to 5 kg/ton and preferably in the range from 0.1 to 2 kg/so the Sol is added to the weight of the dry content in the range from 0.1 to 5% by weight. The amount of polymer in a high degree depends on its type and other required effects. For synthetic polymers are typically no less than 0.01 kg of polymer per ton, calculated as dry polymer on dry fibers and optional fillers. Used amount of from 0.01 to 3, and preferably 0.03 to 2 kg per ton. For polymers based on carbohydrates, such as cationic starch and cationic to Garga, commonly used number not less than 0.1 kg/ton, calculated as dry polymer on dry fibers and optional fillers. They are used in quantities of from 0.5 to 30 kg/ton, preferably from 1 to 15 kg/so the Mass ratio of cationic polymer to solo, calculated as SiO2that is usually not less than 0.01:1, and the and view charges. For polymers with lower nationally, such as cationic starch, alone or in combination with other cationic polymers can be, therefore, used a very high volume with respect to 100:1 or more, the limit is mainly determined by economic considerations. Suitable cationic or amphoteric polymer solu, calculated as SiO2for most systems is in the range from 0.2 to 1 1 to 100. Of course, these sols can be used in paper production in combination with traditional paper additives, such as water agents, agents, hardening in the dry state, agent, hardening in the wet state, etc., It is in particular suitable for the use of aluminum compounds in combination with these nuclei, and cationic polymers, since it is established that aluminum compounds may provide additional retention and dehydration. Can be used any used in paper production is known for the connection of aluminum, for example, alum, semi-aluminum compounds, aluminum chloride and aluminum nitrate. The amount of aluminum compounds can also vary within wide limits, and the suitable is this connection of aluminum, calculated as Al2O3. The ratio does not exceed 3:1 and preferably is in the range from 0.02:1 to 1.5:1. Semi-aluminum compounds may be, for example, polyaluminosilicate, polyaluminosilicate and semi-aluminum compounds containing ions such as chloride and sulfate. Semi-aluminum compounds can also contain anions other than chloride ions, for example, anions from sulfuric acid, phosphoric acid, organic acids such as citric acid and oxalic acid.

Silicic acid sols and polymer can be used in the production of paper from different types of mass of cellulose containing fibers, and the lot shall contain not less than 50% by weight of such fibers with respect to the dry material.

Components can be, for example, used for the mass of fibre chemical pulp such as Kraft pulp and sulfite pulp, thermomechanical pulp, refiner pulp or wood pulp from both the hard and soft wood, and can also be used for mass based on recycled fibers. The mass may also contain mineral fillers traditional species, such as, for example, kaolin, titanium dioxide, gypsum, chalk and tal is the Ktsia, but also other products based on cellulose fibers in the form of a sheet or canvas, such as sheet cellulose, cardboard and thin cardboard, and their manufacture.

The invention is additionally illustrated by the examples, which however do not limit it. Parts and percentages, unless otherwise indicated, refer to parts by weight and percent by mass.

Example 1. Sol S is about 53 containing unmodified aluminum particles of SiO2having a specific surface area of 500 m2/, This Sol corresponds industrial solu developed on the basis of European Patent 41056. The Sol obtained as follows:

1275 g of liquid glass content of 24.2% of SiO2and the mass ratio of SiO2: Na2O 3,45 diluted with 4045 g of water until the content of SiO25,8% Solution of liquid glass is subjected to ion exchange treatment in a column filled with a strongly cation-exchange resin (Amberlite IR 120), and diluted with water to 5.41% SiO2. 4000 g of ion-exchange liquid glass is loaded into the reactor. At careful hashing 354,2 g of water glass (58% SiO2, SiO2Na2O 3,45) is added to ionoobmennogo liquid glass Addition is carried out for 15 sec. Podmechenny of rest the FL heat treatment, the Sol is cooled.

Example 2. According to the invention. Sol S-value 31 containing unmodified aluminum particles of SiO2with a specific surface area of 545 m2/, Sol obtained as follows:

1625 g of liquid glass content of 24.2% of SiO2and the ratio of SiO2Na2About 3,45 diluted with 4075 g of water until the content of SiO26.9% Solution of liquid glass is subjected to ion exchange treatment in the ion exchange column according to example 1, and ion-exchange water glass diluted to 6,419% SiO2. 460 g of ion-exchange liquid glass is loaded in the reactor vessel. With careful mixing 400 g of water glass (6.9% of SiO2, SiO2Na2O 3,45) is added to ion-exchange liquid glass. Podmechenny solution is then heated to 85oC and thermoablative at this temperature for 60 minutes After the heat treatment, the Sol is cooled

Example 3. According to the invention.

Sol S-value 21 containing modified aluminum particles of SiO2with a specific surface area of 631 m2/, Sol obtained as follows:

A dilute solution of liquid glass (SiO2Na2O 3,4) is subjected to ion exchange treatment in a convoy, and it turns out ion the , SiO2Na2O 3,41). The addition is carried out for 15 sec. podmechenny solution is then heated to 75oC and thermoablative at this temperature for 120 minutes, the Sol is cooled and then added H+-saturated cation-exchange resin (Amberlite IP 120) in an amount necessary to obtain a pH of 7.2. The ion-exchange resin and then filtered. To 3770 g Zola with adjusted pH is added 25.4 g of sodium aluminate (Al content2O3- 25,5%). Before adding the sodium aluminate is diluted with 225 g of water. Sol with pH adjusted before adding heated to 45oC and aluminate is added within 60 minutes

Example 4. In this example investigated the effect of retention (retention of fibers and fillers) sols of examples 1 and 2 in paper production. Take the standard weight based on the cellulose content of 60% bleached birch sulfate +40% bleached sulfate pine, to which is added 30% of chalk as a filler and 0.3 g/l Na2SO4H2O. the Mass has a concentration of about 5 g/l, the content of the fine fraction of 38% and a pH of 8.1.

The effect of retention in this and following examples is evaluated using a Britt Dynamic Drainage Jar (device is alzhemier in the paper industry. Sols are used in different quantities in combination with cationic polymer based on acrylamide (Floerger Fp 4100 PG with 10 mol. cationic charge and molecular weight of about 10 million). Cationic polyacrylamide in all trials should be added at 0.8 kg/t and added before the Sol. All the doses in the following examples, calculated on the dry material on dry fibers and optional fillers. The results are given table. 1.

As you can see, the result is a significant improvement effect of holding, when the cationic polyacrylamide is used in combination with silicic acid Sol having a high content of microgel, low S - value according to the invention in comparison with the effect, when the polyacrylamide is used in combination with serial Sol with a low content of microgel.

Example 5. In this example, the retention is measured similarly to the method of example 4 using the Sol of example 3 according to this invention in comparison to known (2) a Sol, which is similar solu of example 3 has an S-value of 21, but which has particles with a specific surface area of 897 m2/, Weight is a standard mass concentration of 5.2 g/l, content of fine fraction of 34% and a pH of 8.1. Nivedana in table. 2.

As you can see, good retention obtained with the sols, modified aluminum, low S-value and specific surface area of about 600 m2/g, as modified alumina sols with a corresponding low S-value, but with particles having a sufficiently large specific surface area.

1. Sol silicate, characterized in that the Sol has a content of disperse phase SiO2corresponding to the S-value in the range from 15 to 40% and contains particles of SiO2modified or unmodified alumina with a specific surface area of 300 to 700 m2/,

2. Sol under item 1, characterized in that the particles of SiO2have a specific surface area of 400 to 650 m2/,

3. Sol on PP. 1 and 2, characterized in that the Sol has a content of disperse phase SiO2corresponding to an S-value within 15 35%

4. Sol on PP. 1 to 3, characterized in that the particles of SiO2are unmodified aluminum.

5. The method of producing paper from wood pulp cellulose containing fibers, comprising adding to the slurry of polymer and anionic Zola silicate, forming and dewatering the obtained slurry on the grid, characterized in that as the polymer charge camionnette S-value in the range of 15 to 40% and containing modified or unmodified aluminum particles of SiO2having a specific surface area of 300 to 700 m2/,

6. The method according to p. 5, characterized in that the use of silicic acid Sol containing particles of SiO2, unmodified aluminum.

7. The method according to PP. 5 and 6, characterized in that the use of silicic acid Sol containing particles of SiO2having a specific surface area of 400 to 650 m2/,

8. The method according to PP.5 to 7, characterized in that the polymer used as the cationic polymer based on acrylamide.

9. The method according to PP. 5 to 8, characterized in that the used pulp pulp containing the filler.

 

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13 cl, 2 ex, 2 tbl, 4 dwg

FIELD: shearing equipment.

SUBSTANCE: device comprises frame, drive, drum, cutting mechanism with movable blade, fixing mechanism for initial blade position fixation relative drum and accumulation means. Device is provided with blocking mechanism, which secures position of movable blade drive shaft, discrete angular drive of movable blade and changes corrugated cardboard blank lengths. The blocking device is made as screw pair. Screw pair nut is pivotally connected to the frame, screw thereof is pivotally linked with double-armed lever having pivot pin aligned with axis of drum rotation. The second arm of the lever is kinematically linked with T-shaped connecting-rod of cutting mechanism drive by control-rod. One end of connecting-rod is connected to crankshaft on drum pivot, another end thereof is mounted on control-rod attached to swinging unit of three-armed lever of discrete angular drive mechanism of movable blade arranged to perform angular swinging about pivot of mutually connected brake drum and drive pinion. Drive pinion is brought into engagement with driven pinion on cutting mechanism drive shaft end. Pair of mutually spring-loaded brake blocks is installed in brake drum kinematically connected through control-rods with ends of oppositely directed arms of three-armed lever. Blocking mechanism for cutting mechanism drive shaft blockage is mounted on another end of above shaft. The blocking mechanism is made as brake drum installed on frame. Pair of mutually spring-loaded brake blocks is arranged into the drum and kinematically linked with double-armed lever by control-rods. The double-armed lever is coaxial with geometrical axis of cutting mechanism drive shaft including lever of mechanism for fixing movable blade in its initial position. The lever is linked with double-armed lever by control-rod. Free end of double-armed rod has roller periodically cooperating with frame rest. Pivot of double-armed lever of fixing mechanism is arranged on bracket of hollow blade holder shaft. Blade holder is installed on hollow shaft with the use of threaded pins. Blade is removably installed in blade holder groove. The blade is made as conventional replaceable bar for cross-cutting corrugated cardboard. Hollow blade holder shaft is coaxially arranged on cutting mechanism drive and may perform limited rotation. Hollow blade holder shaft is connected with cutting mechanism by a plurality of resilient members.

EFFECT: increased output, operational reliability, cutting quality and blank length accuracy.

1 dwg

FIELD: mechanisms and processes for cutting corrugated cardboard.

SUBSTANCE: apparatus includes framework, drive unit, drum, cutting mechanism with movable cutter, mechanism for fixing cutter blade relative to drum and accumulator. Apparatus also includes mechanism for changing length of blanks, unit for fixing its position, blank length indicator. Mechanism for changing length of corrugated cardboard blanks is provided with screw gage whose nut having control knob is jointly secured to framework. Screw of said mechanism is kinematically coupled with two-arm lever mounted with possibility of angle rocking in journal of drum shaft. One arm of lever is jointly coupled with blank length indicator; distal end of its other arm has pivot for mounting driven gear wheel and crank. Said gear wheel engages with driving gear wheel mounted on end of drum. Crank is provided with roller mounted in connecting link of mechanism for converting uniform rotation to intermittent one. Such mechanism includes driving pinion mounted in end of shaft of cutting mechanism and mutually opposite drive members mounted on platform and cyclically engaging with driving pinion. Said platform is mounted on upper ends of pair of parallel tie rods that may perform reciprocation motion in guide and are spring-loaded relative to said guide. The last is mounted with possibility of angular rocking on end of shaft of cutting mechanism near gear wheel. Lower parts of tie rods are arranged with possibility of fixing their position in connecting link of mechanism for converting uniform rotation to intermittent one. In other end of shaft of cutting mechanism are mounted: member for fixing intermediate positions in the form of braking drum secured to framework and pair of mutually spring-loaded and mounted one opposite to other braking shoes with friction cover plates. Braking shoes are adjoined to inner cylindrical surface of braking drum. Mean portions of braking shoes are joined by means of tie rods with two-arm lever mounted in end of shaft of cutting mechanism. In mean part of said shaft along the same axis hollow shaft of cutter holder is arranged, both shafts are mutually joined through bearing assemblies, brackets and set of elastic members placed between shafts. Said shafts are also joined by means of bracket of mechanism (two-arm lever) for fixing cutter blade relative to drum. Rocking axle of mechanism for fixing cutter blade is mounted in bracket of hollow shaft. One end of two-arm lever is joined with tie rod

for coupling with lever of shaft, other distal end of two-arm lever is provided with roller that cyclically engages with stop secured to bracket of framework.

EFFECT: enhanced efficiency, operational reliability, simplified design, lowered labor consumption for maintenance and adjustment, reduced energy consumption, increased useful life period.

5 cl, 31 dwg, 3 tbl

FIELD: process for treatment of textile materials, in particular, whitening of flax fiber for producing of hygroscopic wool used for medicine purposes.

SUBSTANCE: method involves subjecting flax fiber to oxidizing cooking followed by whitening with the use of hydrogen peroxide in the presence of stabilizing preparation based on oxyethylidene diphosphonic acid; after final rinsing, providing brightening processing, preferably with the use of solution containing higher fatty acid based softener used in an amount of 0.5-1.0 g/l. Method is realized in industrial plants with the use of proper equipment and chemical substances available and produced on industrial scale by home enterprises. Said method does not require substantial alterations in chemical processes.

EFFECT: increased whitening extent, capillarity and moisture absorbing capacity of wool produced.

2 tbl, 5 ex

FIELD: paper and cardboard production in pulp-and-paper industry.

SUBSTANCE: method involves preparing cellulose suspension; flocculating and draining suspension on net for producing of paper web; drying paper web. Flocculation process is initially performed with the use of cation-active material, such as natural or synthetic polymer, followed by flocculation with the use of flocculant system including silicon-containing material and organic microparticles having diameter less than 750 nm in unswelled state.

EFFECT: improved draining, holding and forming process.

28 cl, 3 dwg, 12 tbl, 3 ex

FIELD: paper-and-pulp industry.

SUBSTANCE: calcium carbonate product is designed for containing paper and comprises mixture of first and second separate calcium carbonate particles, wherein difference between first and second calcium carbonate particles ranges from about 0.1 μm to 0.2 μm and weight ratio of first to second particles lies between about 50:50 and about 80:20. Pigment is intended for coating paper and made from above-defined product. Method concerns containing paper and comprises preparation of mixed pigment based on calcium carbonate precipitated in the form of aragonite having above-indicated makeup; addition of binder; and deposition of the pigment onto a base paper in the form of binder-containing suspension. Paper is then dried and calendared. Also described are: paper obtained by above method; a method to increase gloss of paper sheet involving operation of including above product into base paper coating suspension; a method to increase gloss of paper involving operation including calcium carbonate product wherein first calcium carbonate particles have average size about 0.4 μm and the second ones about 0.5 μm at their weight ratio 60:40, respectively; a method to increase gloss of paper sheet involving operation of including pigment based on argonite-type calcium carbonate with difference between first and second average particle size values from about 0.1 μm to 0.2 μm and their weight ratio between about 50:50 and about 80:20 into base paper coating suspension.

EFFECT: increased gloss of coated paper sheets.

24 cl, 3 tbl

FIELD: pulp-and-paper industry, in particular paper or board production.

SUBSTANCE: claimed method includes providing of slurry containing cellulose fiber and at least sizing agent interacting with cellulose. Sizing agent is selected from group containing ketene dimmers and acid anhydrides. Cationic vinyl polymer obtained by additional polymerization, containing aromatic units and anionic vinyl polymer obtained by additional polymerization and having molecular mass from 6000-100000 are introduced into slurry. Then obtained slurry is dehydrated and paper leaf is formed.

EFFECT: increased effectiveness of sizing, dehydration and retention.

11 cl, 3 tbl, 2 ex

FIELD: pulp-and-paper industry, in particular, manufacture of paper and cardboard.

SUBSTANCE: method involves preparing aqueous cellulose pulp; adding holding system into cellulose pulp system; draining pulp through cloth for forming of paper web; drying resultant paper web. Holding system comprises swelling clay having whiteness of at least 70.

EFFECT: increased whiteness of paper and improved filler retention capability.

16 cl, 1 tbl, 20 ex

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