Method for production of bleached cellulose material, method for prevention of yellowing and loss of whiteness in bleached craft-cellulose in storage and method for production of paper goods

FIELD: paper industry.

SUBSTANCE: methods refer to manufacturing of bleached cellulose material, prevention of yellowing and loss of whiteness in bleached craft-cellulose, and manufacturing of paper goods. In process of bleached cellulose material manufacturing, bleached craft-cellulose is produced and exposed to contact with sufficient amount of more or several reducing agents. Additionally bleached craft-cellulose is exposed to contact with one or several optical bleach, with one or more chelating agent. Method for prevention of yellowing and loss of whiteness of bleached craft-cellulose in storage includes addition of efficient amount of one or more reducing agent into bleached cellulose and possibly one or more chelating agent, one or more polycarboxylate or their combinations. Method for production of paper goods includes production of bleached craft-cellulose, formation of initial water suspension from it, water drainage with formation of sheet and sheet drying. Besides efficient amount of one or more reducing agent is added into bleached craft-cellulose, initial suspension or sheet. Additionally one or more chelating agent is added there, one or more optical bleach, one or more polycarboxylate, or their combination.

EFFECT: improved quality of paper goods, increased stabilisation of whiteness and increased resistance to yellowing in process of paper production and to thermal yellowing, improved colour pattern.

17 cl, 33 tbl

 

The technical FIELD

This invention relates to compositions and methods for increasing whiteness and improved optical performance, prevent darkening and increase resistance to thermal yellowing in the manufacture of pulp and paper. More specifically, this invention relates to compositions, which as without additives and in the presence of optical brighteners effectively increase the whiteness and improve the optical properties of paper products, as well as increase its thermal stability.

BACKGROUND of the INVENTION

Cellulose, obtained as mechanical and chemical methods of cooking, has a color ranging from dark brown to cream, depending on the type of wood, and used the process of splitting into fibres. The pulp is bleached for manufacture of paper stationery products for different purposes.

The bleaching is the removal or change of the composition of light-absorbing substances contained in the unbleached pulp. When bleaching wood pulp is required to bleach the pulp without the dissolution of lignin. Usually used as a reducing (for example, hydrosulfite sodium)and oxidative (e.g., hydrogen peroxide) bleaching agents. Bleaching is often a multi-stage process. Pulp bleaching is a Supplement to delignification, which the traveler begins at the stage of cooking. Bleaching is often a multi-stage process stage which may include bleaching with chlorine dioxide, oxygen-alkali delignification and bleaching with peroxide.

Change color, often attributed to thermal aging, leads to yellowing and loss of white in various stages of paper production process, it affects the quality of the bleached pulp and the resulting paper products. The industry invests heavily in chemicals such as bleaching agents and optical brighteners that enhance the optical properties of the treated paper and paper products. Today, however, the results are less than satisfactory and economic losses from discoloration and yellowing are for industry permanent serious problem. Thus, there remains a need in the successful and practical solution to the problem of loss of whiteness and undesirable yellowing of pulp and paper.

BRIEF description of the INVENTION

This invention provides compositions and methods for increasing and stabilizing white and enhancing resistance to yellowing in the paper production process.

On the one hand, this invention provides a method for producing bleached pulp material having high whiteness and povyshenno the resistance to thermal yellowing, includes (1) obtaining a bleached Kraft pulp and (2) contact bleached Kraft pulp with one or more reducing agents.

On the other hand, this invention is a method of manufacturing a paper product having improved whiteness and resistance to thermal yellowing, including (1) obtaining bleached Kraft pulp; (2) formation of source water suspension containing bleached Kraft pulp; (3) water abstraction from the original suspension with the formation of the sheet, and (4) drying of the sheet with the formation of paper products, where in bleached Kraft pulp, the original suspension or sheet add an effective amount of one or more reducing agents.

In addition, this invention provides a method of preventing yellowing and loss of white bleached Kraft pulp during storage, including adding in bleached Kraft pulp an effective amount of one or more reducing agents and, possibly, one or more chelating agents and one or more polycarboxylates.

The applicant also unexpectedly found that reducing agents in combination with chelating agents effectively improve the whiteness of paper products, and that reducing agents in combination with optical brighteners enhance the effects of optical otbelivanie improve the color scheme. Thus, in additional aspects, this invention provides a method of use of reducing agents in combination with chelating agents and/or optical brighteners for the manufacture of bleached Kraft pulp having a high whiteness, superior resistance to thermal yellowing and improved color scheme.

Reducing agent, optical brighteners and chelating agents can be used to improve the quality of the desired paper products by themselves or in combination with known additives.

Description of the INVENTION

This invention provides an improved method of manufacture of paper and paper products with high optical white. Stabilization of white color in the fight against thermal yellowing, enhance color and increase the whiteness of bleached Kraft pulp and paper products, made from bleached Kraft pulp can be achieved by adding one or more reducing agents, as specified in this document, pulp, paper, cardboard or tissue anywhere in the paper manufacturing process.

White is the term used to describe the white pulp or paper on a scale from 0% (black) to 100% (relative standard MLA who has absolute whiteness of the Colo 96%) by the reflection of blue light (457 nm) from the paper. "Thermal darkening" represents the loss of white paper and cellulose under the influence of time, temperature and humidity, non-photochemical darkening). "Darkening during storage" represents the loss of white under the influence of time under storage conditions.

Yellowing of bleached Kraft pulp represents the loss of white bleached Kraft pulp, paper, cardboard, tissue paper and other materials made from bleached Kraft pulp under the influence of time.

Reducing agents that are defined in this document, suitable for use with any bleached pulp material used in paper production processes, and any paper products made from bleached pulp. For the purposes of this document, "bleached pulp material" means a bleached pulp and paper products, made from bleached pulp including paper, cardboard, tissue and other

Reducing agents in accordance with this invention include chemical substances that can convert the functional group in the bleached pulp from the higher States of oxidation in low oxidation States. The advantages of such transformations include improving the sustainability of whiteness in paper machine and increase the features of optical whiteness.

In one embodiment of the invention reducing agents are selected from the group consisting of sulfites, bisulfites, metabisulfites (pyrosulfite), sulfoxylates, thiosulfates, dithionites (hydrosulfite), polythionates, formamidinesulfinic acid, its salts and derivatives of the adduct of formaldehyde and bisulfite and other adducts of aldehydes and bisulphite, sulfinamides and ethers sulfinol acid, sulfenamides and ethers sultanovoy acid, sulfonamides, phosphines, phosphonium salts, phosphites and thiophosphites.

For the purposes of this document, the term "sulfites" means dibasic salts of metals with sulphurous acid, H2SO3including dibasic salts of alkali and alkaline earth metals, for example sodium sulfite (Na2SO3), calcium sulfite (S3and other

The term "bisulfite" means monobasic salts of metals with sulphurous acid, H2SO3including monobasic salts of alkali and alkaline earth metals, such as sodium bisulfite (NaHSO3), bisulfite magnesium and other

The term "sulfoxylate" means salt sulfoxylates acid, H2SO2including sulfoxylate zinc (ZnSO2and other

The term "metabisulfite (pyrosulfite)" means salt proserity acid, H2S2O5including metabisulfite intothree the (Na 2S2O5and other

The term "thiosulfate" means salt tournesol acid, H2S2O3including sodium thiosulfate (PA2S2O3and other

The term "Palatinate" means salt politionele acid, H2SnO6(n=2-6), including tritional sodium (PA2S3O6), salt ditionally acid, H2S2O6for example ditional sodium PA2S2O6and other

The term "dithionite (hydrosulfite)" means salt dithionite (carnavalito) acid, H2S2O4including dithionite (Hydrosulphite) sodium (Na2S2O4), dithionite magnesium (gS2O4and other

The term "formamidinesulfinic acid (FAS, FAS)" means a compound of the formula H2NC(=NH)SO2H and its salts and derivatives, including sodium salt

H2NC(=NH)SO2Na.

The term "adducts of aldehydes and bisulfite" means the compounds of formula R1(HE)SO3N and their metal salts, where R1selected from alkyl, alkenyl, aryl and arylalkyl groups. The corresponding adducts of aldehydes and bisulfite include an adduct of formaldehyde and bisulfite of NON2SO3PA and others

The term "sulfonamide and ethers sulfinol acid" refers to compounds of formula R1-S(=O)-R2where R1described earlier in this document, a Rsub> 2choose from or SIG3and NR4R5where R3-R5are groups independently selected from alkyl, alkenyl, aryl and arylalkyl groups. Among the relevant sulfinamides is ethylsulfinyl

(CH3CH2S(=O)N(CH3)2and other

The term "sulfonamide and ethers, sultanovoy acid" refers to compounds of formula R1-S-R2where R1and R2have been described above. Among the relevant sulfenamide is ethylsulfinyl

(CH3CH2SN(CH3)2and other

The term "sulfonamides" means substances of the formula R1-C(=S)-NR4R5where R1, R4and R5have been described above. Among the corresponding sulfonamides include

(CH3CH2C(=S)N(CH3)2and other

The term "phosphine" means derivatives of phosphine, PH3usually replaced by organic substituents phosphines of the formula R6R7R8P, where R6-R8independently selected from H, alkyl, alkenyl, aryl, arylalkyl groups and NR4R5where R4and R5have been described above. The number of the corresponding phosphines include (NON2)3R (THF) and other

The term "phosphites" means derivative of phosphorous acid P(OH)3including substituted the authority of the Czech deputies of the phosphites of the formula (R 3O)(R4O)(R5O)R, where R3-R5have been described above. Among the corresponding phosphites is (CH3CH2O)3R and others

The term "theophostic" means derivative thiophosphoric acid HSP(OH)2including substituted organic substituents of thiophosphate formula (R3O)(R4O)(R5S)P, where R3-R5have been described above. Among the relevant thiophosphites is (CH3CH2O)2(CH3CH2S)P and other

The term "salt of the phosphonium means are replaced by organic substituents phosphines of the formula R1R3R4R5P+X-where R1and R4-R5were described above, and X represents any organic or inorganic anion. Among the corresponding phosphonium salts include (HO2CCH2CH2)3P+HCl-(THF), [(HOCH2)4P+]2(SO4)2-(S) and other

The term "alkenyl" means a monovalent group derived from a linear or branched hydrocarbon by removal of one hydrogen atom and containing at least one double bond in the carbon-carbon bonds. Alkenyl may be unsubstituted or substituted by one or more groups selected from: amino, alkoxy, hydroxy groups and halogen.

The term "alkoxy" means alkyl group, p is soedineniya to the main fragment of the molecule through an oxygen atom. Among the relevant alkoxygroup include methoxy, ethoxy-, propoxy-, butoxypropyl and other Preferred are methoxy and ethoxypropan.

The term "alkyl" means a monovalent group derived from a linear or branched saturated hydrocarbon by removal of one hydrogen atom. The alkyl may be unsubstituted or substituted by one or more groups selected from: amino, alkoxy, hydroxy groups and halogen. Among the respective alkyl groups include methyl, ethyl, n - and isopropyl-, n-, sec-, ISO - and tert-butyl, etc.

The term "alkylene" means a divalent group derived from a linear or branched saturated hydrocarbon by the removal of two hydrogen atoms, for example methylene-, 1,2-ethylene, 1,1-ethylene, 1,3-propylene-, 2,2-dimethylpropylene and other

The term "amino" means a group of General formula-NY1Y2where Y1and Y2independently selected from H, alkyl, alkenyl, aryl and arylalkyl groups. The number of matching amino groups include amino(-NH2), methylamino, ethylamino, isopropylamino, diethylamino-, dimethylamino-, methylethylamine and other

The term "aryl" means an aromatic carbocyclic radicals and geterotsiklicheskikh radicals having from about 5 to about 14 atoms in the ring. The aryl may be nezameshchenny the or substituted by one or more groups, which are selected from: amino, alkoxy, hydroxy groups and halogen. Among the corresponding aryl groups are phenyl-, naphthyl-, tenantry, intracel-, pyridyl-, furyl-, pyrrolyl-, hinely, thienyl-, thiazolyl, pyrimidyl, intelligroup and other

The term "arylalkyl" means an aryl group attached to the main fragment of the molecule through alkylenes group. Among the relevant alcylaryl groups include benzyl, 2-phenylethyl and other

The terms "halo" and "halogen" means chlorine, fluorine, bromine and iodine.

The term "salt" means a salt of a metal, ammonium, substituted ammonium or phosphonium organic or inorganic anionic counterion. Among the appropriate metals include sodium, lithium, potassium, calcium, magnesium and other among the respective anionic counterions include sulfite, bisulfite, sulfoxylate, metabisulfite, thiosulfate, polythionate, hydrosulfite, formamidinesulfinic and other

In one embodiment of the invention reducing agent selected from the group consisting of substituted Torchinov, sulfites, bisulfites and metabisulfites.

In one embodiment of the invention regenerating agent is sodium bisulfite.

The method according to this invention can be implemented on standard papermaking equipment. Although the paper on which the equipment is designed differs according to the modes and structures with mechanical point of view, the processes of making paper on a variety of hardware include the same stage.

The manufacture of paper usually includes the stage of pulping, bleaching of pulp, the manufacture of paper pulp, stage wet part and stage dry part.

At the stage of pulping individual fibers of cellulose otscheplaut from a source of cellulose by mechanical and/or chemical effects.

According to the invention bleached pulp material is a Kraft pulp.

At the stage of manufacturing paper pulp Kraft pulp suspended in water. Also at this stage a lot, you can enter additives such as bleaching agents, dyes, pigments, fillers, antimicrobial agents, inhibitors pricing, pH control agents and methods to speed up dehydration. As used herein the term "manufacture of paper pulp includes operations such as dilution, screening and cleaning suspension of paper pulp that can be performed before forming the paper web.

Stage wet end of the paper manufacturing process includes applying a suspension of paper pulp or fiber suspension into a mesh or cloth papermaking machine for forming a continuous web of fibers, the diversion of water from the cloth and seal sheets ("pressed") with f is armirovanie sheet. The process according to this invention can be used on any modern paper machine. Such machines may include, in particular, kruglosutochno machine, clinocerinae machine, twin-wire forming machines, machines for the production of sanitary-hygienic paper and others, as well as their modifications.

At the stage of the dry part of the paper manufacturing process, the paper web is dried, it can also be subjected to additional processing, such as extrusion, calendering, coating with surface modifiers, printing, trimming, embossing, etc. in Addition to the size of the machine and calender coating can be applied to dry paper using a rod with a spray nozzle.

The applicant also unexpectedly found that reducing agents in combination with chelating agents, as described above, effectively improve the whiteness of paper products due to the higher thermal stability of the mass and decreases in the mass of the chromophore structures.

In one embodiment of the invention in bleached Kraft pulp or paper products add one or more chelating agents. Suitable chelating agents for this invention include compounds capable of helatoobrazovatel with transition metals form coloured products with components mass and ka is alsinoideae reaction, resulting in staining, in bleached pulp and paper products.

In one embodiment of the invention chelating agents are compounds selected from the group consisting of organic phosphonates, phosphates, carboxylic acids, dithiocarbamates, salts of the substances listed, and any combinations thereof.

The term "organic phosphonates" means organic derivatives of phosphonic acid, HP(O)(OH)2containing at least one link With-R, e.g GEDF (CH3S(HE)(R(O)(OH)2), 1-hydroxy-1,3-propanediyl-bis-phosphonic acid ((BUT)2P(O)CH(OH)CH2CH2P(O)(OH)2)); preferably contains one bond C-N, related with communication With-R, e.g DMFC ((HO)2P(O)CH2N[CH2CH2N(CH2P(O)(OH)2)2]2), AMF (N(CH2P(O)(OH)2)3), ((HO)2P(O)CH2)2NCH(CH3)CH2(OCH2CH(CH3))2N(CH2)6N(CH2P(O)(OH)2)2), ((HO)2P(O)CH2)2N(CH2)6N(CH2P(O)(OH)2)2), (N(CH2P(O)(OH)2)2CH2CH2OH) and other

The term "organic phosphates" means organic derivatives of phosphoric acids, P(O)(OH)3containing at least one link With-R including ester of triethanolaminato (N(CH2CH2The OP(O)(OH)2)3and other

The term "carboxylic to the slots" means organic compounds, containing one or more carboxyl groups, -C(O)HE, preferably aminocarbonyl acid containing one bond C-N, related with communication WITH CO2N, for example EDUC ((HO2CCH2)2NCH2CH2N(CH2CO2H)2), DTPY ((HO2CCH2)2NCH2CH2N(CH2CO2H)CH2CH2N(CH2CO2H)2) and others, as well as their salts with alkali and alkaline earth metals.

The term "dithiocarbamate" means a Monomeric dithiocarbamate, polymer dithiocarbamate, dithiocarbamate of polydiethylene, 2,4,6-dimercapto-1,3,5-triazine, ethylenebisdithiocarbamate disodium, dimethyldithiocarbamate, sodium and other

In one embodiment of the invention the chelating agent is a phosphonate.

In one embodiment of the invention, the term "phosphonates" refers diethylenetriaminepentaacetate acid (DMFC) and its salts.

In one embodiment of the invention the chelating agent is a carboxylic acid.

In one embodiment of the invention carboxylate selected from diethylenetriaminepentaacetic acid (DPUC) and its salts, as well as ethylendiaminetetraacetic acid (ETUC) and its salts.

The applicant also unexpectedly found that the reducing agent used in combination with optical from what elevates (OO) enhances the effect of optical brighteners (OO). Reducing agent also improves the system colors. This allows to reduce the number of OO and brighteners, such as blue dyes needed to obtain comparable white and color. Replacement parts OO dyes and reducing agents allows producers of pulp and paper to reduce production costs and reduce the total number of OO and dyes in products, while maintaining an acceptable level of whiteness of paper products and getting the desired color. In some cases, you can completely abandon dyes and preserve the color.

Thus, in another embodiment of the invention in the bleached pulp or paper products add one or more optical brighteners (OO).

The term "optical brighteners" means fluorescent dyes or pigments that absorb ultraviolet radiation and re-emit it at the higher frequencies of the visible spectrum (blue), thus adding to the paper pulp composition they give a sheet of paper white, shiny appearance. Among the respective optical brighteners include (without limitation) the azoles, biphenyls, coumarins; furans; ionic brighteners, including anionic, cationic and anionic (neutral) compounds, for example compounds Eccobrite® and Eccowhite®, supplied by Eastern Color &Chemical Co. (Provdence, Rl); naphthalimide; pyrazine; substituted (for example, sulfonated) stilbene, such as a set of optical brighteners Leucophor®, supplied by Clariant Corporation (Muttenz, Switzerland), and Tinopal®, supplied by Ciba Specialty Chemicals (Basel, Switzerland); salts of these compounds, including (but not limited to salts of alkali metals, salts of alkaline earth metals, salts of transition metals, organic salts and ammonium salts of these bleaching agents; and combinations of one or more of the above agents.

In one embodiment of the invention optical brighteners are selected from the group desulfurating, tetrasulfonic and hexachlorophane OO production Tinopal®.

Dosage reducing agents, chelating agents and/or optical brighteners is defined as the number of agents necessary to achieve the required brightness and resistance to yellowing of bleached pulp or paper products made from bleached pulp, and can be determined by an experienced technician on the basis of the characteristics chelating agent or optical bleach, processed pulp or paper and method of application.

An effective amount of reducing agent added to the bleached pulp or paper products, is the amount of the reducing agent, which is th increases whiteness and resistance to thermal yellowing of the pulp or paper compared with cellulose or paper, not exposed to processing regenerating agent. How to determine whiteness and resistance to thermal yellowing described in this document.

Usually bleached Kraft pulp or paper products add about 0.005 to 2, preferably about from 0.05 to 0.25 wt.% the reducing agent based on kiln dried Kraft pulp.

In typical applications to bleached Kraft pulp or paper products add approximately from 0.001 to 1, preferably from about 0.01 to 0.1 wt.% chelating agent on the basis of phosphonates, phosphates or carboxylate and/or from about 0.002 to 0.2 wt.% chelating agent-based dithiocarbamates based on kiln dried Kraft pulp.

Optical brighteners are usually added in amounts of about 0.005 to 2, preferably from 0.05 to about 1 wt.% optical Brightener based on kiln dried Kraft pulp.

Reducing agents, chelating agents and/or optical brighteners can be added to a bleached pulp or paper anywhere in the process of making paper or tissue paper. Among the respective add include (not limited to): (a) fibrous suspension in the latent pool; (b) cellulose after the stage of bleaching in a collecting pool for the masses, mixing or PE is austrom pool; (C) the pulp after bleaching, washing and drying, followed by drying in a tumble dryer or air drying; (d) before or after the cleaners; (e) before or after the mixing of the pump before the pressure box of the paper machine; (f) circulating water of the paper machine; (g) the bunker or masalawala; (h) in the press section, using, for example, glueing machine, coating machine or nozzle rack; (i) drying part, for example, through the sizing machine, coating machine or nozzle rack; (j) the calender, using, for example glue the drawer; and/or (k) paper in the external coating machine or glueing machine; and/or (l) installation of control curls.

The exact location of the addition of reducing agents, chelating agents and/or optical brighteners will be determined by the specific equipment, the exact conditions used process, etc. In some cases to achieve maximum efficiency, reducing agents, chelating agents and/or optical brighteners can be added in one or more places.

The introduction can be performed during the paper manufacturing process by any standard means, including "flow two streams, when a portion of the reducing agent, chelating agent and/or optical Brightener is injected at one point the e papermaking process, for example, in mass or raw sheet (before drying drums), and the remainder added to the next point, for example in the size of the machine.

Chelating agent and/or the optical Brightener can be added to the bleached pulp or paper products before, after or simultaneously with the regenerating agent. Optical Brightener and/or a chelating agent may also be a single formula with regenerating agent.

In one embodiment of the invention, one or more reducing agents and one or more optical brighteners mixed with solution for surface sizing and put in the size of the machine.

In one embodiment of the invention reducing agent added to bleached Kraft pulp after the stage of bleaching in a collecting pool for the masses, mixing or bypass the pool.

In these places, reducing agents, chelating agents and/or optical brighteners can be added together with carriers or additives commonly used in the manufacture of paper, for example retaining additives, adhesive additives and solutions, starch, precipitated calcium carbonate, flour, calcium carbonate or other adhesives or fillers, as well as bleaching additives.

In one embodiment of the invention, postanal the living agents, chelating agents and/or optical brighteners used in combination with one or more partially neutralized polycarboxylic acids, preferably such polycarboxylic acids as polyacrylic acid (CH3CH(CO2N)[SN2CH(CO2N)]nCH2CH2CO2N, where n is from about 10 to 50000. Polycarboxylic acid may be neutralized to the desired pH (usually 5-6, as discussed below) alkali such as sodium hydroxide.

In one embodiment of the invention is proposed, comprising one or more chelating agents, one or more reducing agents and one or more polycarboxylic acids. The composition preferably has a pH of about 4-7, more preferably about 5-6.

In one embodiment of the invention is proposed, comprising one or more reducing agents, one or more optical brighteners, and possibly one or more chelating agents, one or more of polycarboxylates or combinations thereof. The trains in this implementation variant of the invention preferably have a pH of about 7 to 11, more preferably about 9-10.

Reducing agents, chelating agents, optical brighteners and polycarboxylate can be used in addition to other additives, is commonly used in paper making to improve one or more properties of the finished paper products, facilitate the manufacture of the paper or for both these purposes. These supplements usually are regarded as functional additives or Manager.

Functional additives usually referred to as such additives, which are used to improve or message of some specially selected properties of the finished paper products, these include (not limited to) bleaching agents, dyes, fillers, sizing agents, starches and adhesives.

Control additives, on the other hand, is the additives introduced during the paper manufacturing process to improve the whole process, which does not have a significant effect on the physical properties of paper. To the control additives include antiseptics, retaining additives, defoamers, pH control agents, agents to control the layering and drying means. Paper and paper products produced using the process according to this invention may contain one or more functional and/or control additives.

Pigments and dyes give the paper color. Among the dyes are organic compounds having a conjugated system of double bonds; azo compounds; metal-containing azo compounds; anthraquinones; treeline connection, for example triarylmethane; quinoline and related compounds; acid dyes (anionic organic is such a connection, containing sulphonate groups and used by precipitating organic compounds such as alum); basic dyes (cationic organic dyes containing functional amino group) and direct dyes (acid dyes of the type having a high molecular weight and specific direct affinity to cellulose), and combinations of the above suitable dyes. Pigments are finely ground minerals that can be white or colored. The most commonly used in papermaking industry pigments are clay, calcium carbonate and titanium dioxide.

To improve the lightproof and white paper add fillers. Among the fillers are not limited to, calcium carbonate (calcite); precipitated calcium carbonate (COC); calcium sulfate (including various hydrated forms); calcium aluminate; zinc oxide; magnesium silicates, such as talc; titanium dioxide (Tio2), such as anatase or rutile, clay or kaolin, consisting of hydrated SiO2and Al2About3; synthetic clay; mica; vermiculite; inorganic fillers; perlite; sand; coarse sand; Sandstone; glass beads; aerogels; xerogels; hydrogels; ash; aluminum oxide; microspheres; hollow glass spheres, porous the ceramic spheres; tube; seeds; light polymers; xonotlite (crystalline gel of calcium silicate); pumice stone; slate; waste concrete production; partially hydrogenated or dehydrogenated particles hydraulic cement; diatomaceous earth, and combinations of these substances.

Sizing agents are added to the paper during the production process, to improve the resistance to the permeability of the paper for liquids. Sizing agents are divided into internal sizing agents and external (surface) sizing agents, they can be used for strong sizing, poor sizing, or both types of sizing. More specifically, sizing agents include resins; resin, precipitated with alum (Al2(SO4)3); abietic acid and homologues abietic acid, for example neobyatnoy acid and levopimaric acid, stearic acid and derivatives of stearic acid; a carbonate of ammonium zirconium; siloxane and elexandria substances, such as RE-29, supplied by GE-OSI-SM-8715, supplied by Dow Corning Corporation (Midland, MI); fluorine-containing compounds of General formula CF3(CF2)nR, where R is the anionic, cationic or another functional group, such as Gortex; dimer of alkylbetaine (DAC), such as Aquapel 364, Aquapel (1752, Heron) 70, Hercon 79, Precise 787, 2000 and Precise Precise 3000 to the e are supplied to the market by the company Hercules, Incorporated (Wilmington, delawar); and alkilirovanny succinic anhydride (AA); emulsion AA or DUCK in a modified starch; AA containing alum and starch; hydroxymethylpropane starch and carboxymethylcellulose (CMC); polyvinyl alcohol; methyl cellulose; alginates; waxes; emulsion waxes, and combinations of these sizing agents.

Starch is used in paper production for a variety of purposes. For example, it acts as a holding agent, agent imparting dry strength and surface sizing agent. The starches include (without limitation) amylose; amylopectin; starches containing different amounts of amylose and amylopectin, for example 25% amylose and 75% amylopectin (corn starch), and 20% amylose and 80% amylopectin (potato starch); prepared enzymes starches; hydrolyzed starches; hot starches, also known as "klasterizovannykh starches"; cationic starches, similar to the results obtained by the reaction of starch with Quaternary amine with formation of Quaternary ammonium salts; anionic starches; ampholytic starches (containing both cationic and anionic groups); pulp and substances obtained from cellulose, and combinations of these substances.

The method according to this invention provides a paper product with a white surface. Cu is IU, new composition additionally protects the paper from discoloration when used regularly for a long time.

The foregoing can be better explained using the following examples, which are given for illustrative purposes and are not intended to limit the scope of the invention.

9,8
Table 1
The appropriate composition (water not included)
Component% component
Composition AndTMPC7,6
Polyacrylate sodium3,5
NaOH1,5
Metabisulphite sodium26,6
CompositionTMPC9,0
NaOH3,6
Metabisulphite sodium27
Com is osize TMPC6,0
NaOH3,0
Metabisulphite sodium30
Composition DTMPC5,0
DPUC4,1
NaOH1,5
Metabisulphite sodium30
Composition ETMPC7,4
NaOH5,5
Metabisulphite sodium16,7
FAS7,7
Composition FTMPC4,2
NaOH2,8
Metabisulphite sodiumto 19.9
S
DPUC4,1
NaN020,1
Composition GDPUC2,9
Polyacrylate sodium1,0
NaOH1,3
Metabisulphite sodium30,0

EXAMPLES

In these examples to bring the pH of the relevant agent or composition to a desired value to it was added 50% aqueous sodium hydroxide solution. All percentages in these examples are given in percent by weight on a dry pulp.

In these examples, the following terms have the specified value.

"White" for white according to the international standard ISO R457 (TARR 525); "Yellow" yellow E; "White 0 for brightness R457 after application; "White TS" for whiteness R457 after thermal aging; "Loss TS for loss of whiteness after thermal aging; % ing. for the degree of inhibition of the loss of whiteness: % ing.=100-100*(White 0-White TC)/(White 0-White TC)control; "Bleaching for bleaching A: the MM for thermo-mechanical wood pulp; CTMP for chemicomechanical wood pulp; DFID for wood pulp refiner; OO for optical Brightener; FAS for formamidinesulfinic acid; TKF for ( HOCH2CH2)3PHCl, hydrochloride Tris-carboxyethylidene; S for [(NON2)4R]2(SO4), sulfate Tetra-hydroxymethylpropane; for TNR (NON2)3R, Tris-hydroxymethylpropane; EDTA for (HO2CCH2)2NCH2CH2N(CH2CO2H)2, ethylenediaminetetraacetic acid; DPUC for (HO2CCH2)2NCH2CH2N(CH2CO2H)CH2CH2N(CH2CO2H)2, diethylenetriaminepentaacetic acids;

DMFC for H2O3RSN2N[CH2CH2N(CH2RHO3H2)2]2, dietilen-triamine-pentamethylene phosphonic acid; and DTC for of sodium dimethyldithiocarbamate.

Procedure

Sheets of paper with a handmade character made from bleached pulp and then used in experiments, in which the reducing agent was applied as a wet sheet (before or after the press) before drying cylinder, or after drying cylinder (temperature drying cylinder: 100°C). As a third option used the flow into two streams. For surface sizing produced additional turnover drum dryers.

Zagruzki the test agent or composition was determined relative to the dry weight of the sample pulp. The solutions of an agent or composition was applied using a rod so evenly as possible, in the form of aqueous solutions. Test sheets were dried using a laboratory drum drier to common conditions (one turn) and then, after measuring the whiteness, were subjected to tests on accelerated aging as described below.

Experiments on yellowing (thermal ageing, paper)

Samples of 3×9 cm, cut from the test sheet was placed in a water bath at 70°C, 100% humidity for approximately 3 days. Before measuring the whiteness of the samples were put into a state of balance in a room with constant humidity.

Experiments on yellowing (thermal aging of cellulose)

Cellulose (concentration of 10%, 5 g of cellulose in the basis n / a) was Packed in plastic bags and placed in a water bath at 70°C for 3-6 hours. Before measurement of whiteness produced sheets of paper manual low tide, which led to a state of equilibrium in a room with constant humidity.

Equipment for testing

Laboratory drum dryer.

"Elrepho 3000," "Technidyne Color Touch 2 (ISO model)or another tool for measuring whiteness.

Fluorescent spectrophotometer Hitachi F-4500 or other instrument for measuring the relative fluorescence intensity. The introduction of.

Set for applying glue to the surface (the tablet, and W is Anga for dimension 3).

Room with constant humidity (23°C., humidity 50%).

Water bath/incubator containing floating plastic container with samples of paper

Cuvette 100 ml for method with impregnation.

The procedure is applied on a dry surface (Surface sizing)

1. Preparing a sheet of handmade paper size 20,32×20.32 cm (8×8 inches) in accordance with standard procedure. Target dry weight of the finished paper was 2.5, the Wet paper sheet was passed through one cycle in the dryer drum.

2. The sheet was cut into 4 smaller squares (approximate mass of each - 0.625 g).

3. One side of the small square (test sheet) was glued to a glass substrate using the adhesive tape of greater length than the side of the square.

4. The rod was placed on the adhesive tape, on the tape next to the post using a micropipette inflicted 0.2 ml of the mixture.

5. At some distance inflicted solution agent so that it is uniformly distributed over the tape and could cover the entire test sheet.

6. Quickly shifting solution with tape, distributing it over a sheet with the rod so that the complex solution of the reducing agent is evenly distributed throughout the sheet.

7. The test sheet was dried in a drum dryer and put it in balance with the environment at room temperature.

8. Measured white and yellow.

procedure applied on dry surface (Surface sizing, impregnation)

1. Preparing a sheet of handmade paper size 20,32×20.32 cm (8×8 inches) in accordance with standard procedure. Target dry weight of the finished paper was 2.5, Missed a wet sheet of paper through one cycle in the dryer drum.

2. Cut a strip of 1/8 sheet (0.31 g).

3. In the test tube 50 ml of prepared solutions pre-brewed starch (if necessary) and a reducing agent, based on a predetermined level of adhesion and the target dosage.

4. The paper strip was immersed in the solution for 10 seconds, and gave him to drain for 35 seconds and passed through the press.

5. The test sheet was dried in a drum dryer and put it in balance with the environment at room temperature.

6. Measured white and yellow.

Application procedure wet end

1. Produced sheet 20,32×20.32 cm (8×8 inches), water was removed by using a press with two sheets of filter paper on the bottom and one sheet of filter paper on top. The concentration of the extruded sheet was approximately 40%.

2. After the media sheet has picked up the top sheet of filter paper and the bottom sheet of filter paper.

3. Sheet, one bottom sheet of filter paper was cut into 4 smaller test sheet of equal size (the approximate weight of each sheet 0.625 g).

4. Test sheet together with f is travalini paper glued on one side to the glass substrate, as described in "Procedure applied on a dry surface.

5. Solution 1 was applied, as described in "Procedure applied on a dry surface.

6. After application of the test sheet with wet blotting paper was removed from the glass substrate, the adhesive tape was removed and the blotter paper was separated from the test sheet. Blotting paper was removed.

7. The test sheet was dried in a drum dryer and brought him into equilibrium with the environment at room temperature.

Application procedure two threads

1. Prepared a paper size 20,32×20.32 cm (8×8 inches) in accordance with standard procedure.

2. The sheet formed on the screen, and then closed 4 sheets of blotting paper.

3. Thereafter, the sheet with sheets of blotting paper pressed with heavy duty metal clip. This process allowed us to remove from the sheet excess water to increase the concentration of the sheet to approximately 20%.

4. With a sheet of paper took three of the top sheet of blotting paper.

5. Sheet of paper and one sheet of blotting paper after it was removed from the screen and cut into 4 smaller pieces, as described in "Procedure for application in wet end".

6. Sheet of paper and one sheet of blotting paper was attached to a glass substrate, as described in "Procedure for application in wet end".

7. Solution 2 was applied,as described in "Procedure for application in wet end".

8. Then test the paper sheet is pressed with 2 sheets of blotting paper on each side.

9. After pressing blotting paper was removed, and the test paper sheet was dried on a drum.

Then the sheet was applied a solution of 2, dried and measured in accordance with steps 3 through 8 in the section "Procedure applied on a dry surface.

The procedure of introducing a lot

Chemicals were added directly to the mass (pool diluted mass or pool thickened mass) and was stirred in sealed packages. When the procedure of introducing a lot to improve NGO chemicals were added directly to bleached Kraft pulp with a concentration of 20%, was stirred in sealed packages and left at 45-80°C for 30 minutes Mass was diluted to a concentration of 5%was added OO, mixed and liquid mass was left at 50°C for 20 minutes and Then the liquid mass was further diluted and made sheets of paper hand casting according to the standard procedure.

Test results

1. Test PPM

Data for testing were collected at plant Kraft pulp Southern. Experimental data is shown in the table below. In several tests the application of the product (composition a) size machine, with OO in surface sizing, quantities 2,226 kg/tonne (5 lb/ton) and more consistently provided for improving the whiteness of 1.5 points followed by improving the color of the paper (reflected in the decrease of the values of "DE"). Return to the standard conditions of grinding (without impregnating composition) resulted in the decrease of white to the base level. The experiment was repeated three times.

Table 2
These tests: Whiteness R457, bleaching E, DE(ΔE)=SQRT[(L0-L)2+(a0-a)2+(b0-b)2]
Time, hDosage, kg/ton (lb/t)WhiteDEBleaching E
0094,51,99142,24
0,5894,51,61144,95
1,17094,51,83143,34
1,75094,51,93143,52
2,330 94,5152146,66
2,921,814(4)95,250,71150
3,51,814(4)95,250,89148,29
4,081,814(4)95,50,88of 148.4
4,672,268 (5)960,76149,46
the 5.252,268 (5)960,72149,84
of 5.832,722 (6)960,44152,6
6.42 per3,329 (8)960,44156,01
73,329 (8)960,35154,15
7,583,329 (8)95,750,4154,92
8,174,536 (10)960,52152,24

Researched a few songs and got good results with laboratory simulation introduction in factory mass. Chemical substances (composition), not listed in table 1, were applied as 40% solutions.

2. Reducing agent: sodium metabisulfite (30% solution)

Table 3
A mixture of Kraft CTMP 1, inlet box, surface coating with starch (solution for surface sizing) with two sides
No.ResearchWhite
1Control94,34
20,27% sodium metabisulfite96,17

Table 4
A mixture of Kraft CTMP 2, inlet box, surface is e coating with starch (solution for surface sizing) with two sides
No.ResearchWhite
1Control94,93
20,27% sodium metabisulfite95,63

Table 5
A mixture of Kraft CTMP 3, an imaginary box
No.ResearchWhiteThe win against the controlThe win against PA
1Control85,470
20,2% OO89,78or 4.310
30,2%OO+0.2% of the composition And91,055,581,27
40,2%OO+0,054% sodium metabisulfite90,6 5,130,82
50,054% sodium metabisulfite86,310,84

Table 6
Finished (taped) Kraft 1, surface coating with starch (solution for surface sizing) on the one hand
No.ResearchWhite
1Control80,00
20,27% sodium metabisulfite80,50

Table 7
Finished (taped, OO) Kraft 2, surface coating with starch (solution for surface sizing) on the one hand
No.ResearchWhite
1Control94,78
20,27% sodium metabisulfite 95,39

Table 8
Mechanical Kraft pulp 2
No.ResearchWhite
10.2% sodium metabisulfiteexpenses 63.81
2Drum drying (100°C)62,28
3Air drying (23°C)64,87

Table 3-8 illustrate the impact of a reducing agent bisulfite sodium (metabisulphite) and compositions that increase the whiteness, the whiteness of the paper: reducing agent increases the whiteness (table 3-8), partially compensating the loss of white on the drying apparatus (table 8). Chemicals increases the whiteness in the presence OO (table 5).

3. Reducing agents, in addition to sodium metabisulfite

Drawing in model solution for surface sizing with starch

Table 9
TM
No.Research WhiteYellow
10,2% THF78,6612,38
20.2% FAS78,7512,20
30,2% TKF79,2012,13
40.2% FAS78,0012,17
50,2% THF+0,01% NaNO2*79,2212,00
60,2% THF+0,01% NaNO2*79,1112,12
7Control77,5112,98
* Activator

Table 10
TM
No.ResearchWhiteYellow
1Control78,8311,95
20,2% BCGF81,0610,90

Table 11
UMM (RMP)
No.ResearchWhiteYellow
1Control76,7513,57
20,2% BCGF78,5912,64
30,2% BCGF+0,01% NaNO278,7512,54
40,2%TKO+0,01%NaNO278,3812,70
* Activator

In tables 9-11 demonstrates the effect of reducing agents other than sodium metabisulfite, such as FAS and compounds of phosphorus (III).

4. Composition chelating agent metabisulfite

Table 12
Kraft hardwood pulp 3, an imaginary box
No.ResearchWhite
10% OO 287,56
20% PA 2+0,1% song88,07
320% OO92,08
420% GS+0.1% composition92,80
540% OO93,05
640% GS+0.1% composition93,60
7100% OO93,43
8100% GS+0.1% composition93,95
Table 13
A mixture of Kraft CTMP 3, activation of the optical Brightener
No.ResearchWhiteWon numerous. by Rel. controlSynergism
1Control85,480-
20.2% song86,791,35-
30,2% OO89,74,21-
40,35% OO90,735,22-
50.1% composition86,340,81-
60,2% OO+0.2% song91,4of 5.82 0,26
70,2% OO+0.1% composition90,78the 5.250,23
80,35% OO+0.2% song92,556,870,30
90,35% OO+0.1% composition92,066,540,51

Table 14
Activation of the optical bleach Kraft pulp 4, the composition C (0, 0.2 percent) OO (0, 0,2%)
WhiteRelative to (0,0)
OO1
WITH, OO078,240
WITH, OO0,279,741,5
C0,2, OO080,432,19
C0,2, OO0,282,3 4,29
Synergism0,6

Table 15
A mixture of Kraft CTMP 1, inlet box, to activate the optical bleach, as measured by fluorescence intensity
SampleThe intensity of fluorescence
Control33746
0.2% of the composition And36149
0,35% OO106233
0.1% of the composition A+0,35% OO111609
0.2% composition A+0,35% OO116373
0.3% of the composition A+0,35% OO119845

Table 16
Kraft pulp inlet box containing OO, activation of the optical Brightener, as measured by fluorescence intensity
SampleThe intensity of fluorescence
Control 87140
0.1% of the composition And106217
0.2% of the composition And108942
0,2% OO117513
0.2% composition A+0,2% OO120837

Table 17
Mixed wood pulp (25% coniferous, 40% hardwood Kraft pulp, 35% free of paint), the activation of optical Brightener, as measured by fluorescence intensity
SampleThe intensity of fluorescence
Control57121
0.2% of the composition And57567
0,91% OO61339
0.2% composition A+0,6% OO60783
0.2% composition A+0,45% OO60868
0.2% composition A+0,3% OO59924

Table 18
TM
About Aziz WhiteYellow
Control78,4312,06
0.2% composition81,1110,70
0,2% (sodium Metabisulfite 3: DPUC 1)81,3110,52

Table 19
TM
No.SampleWhiteYellow
1Control78,8311,95
20.05% FAS+0,15% composition81,35of 10.72
30,2% BCGF81,0610,90
40,1% WTGF+0.1% composition80,2811,32
50,2% (WTGF:DMFC) of 10.73
60.2% composition81,3010,90

Table 20
Hardwood Kraft pulp 2
No.SampleWhiteYellow
1Control87,484,21
20.2% composition88,38the 3.65
30,2% (sodium metabisulfite 30: DPUC 5: DMFC 5)88,403,35

Table 21
Kraft pulp 2, surface sizing
No.SampleWhiteYellow
10,513% of the composition And, drum drying88,41 3,51
2Drum drying87,504,01
3Air drying88,16of 3.56

Table 22
Kraft pulp 2, surface sizing
No.SampleWhite
10.2% of the composition And, drum drying88,31
2Drum drying87,76
3Air drying88,67

Table 23
A mixture of Kraft pulp, the load put on the box, causing the wet end
White
0.1% sodium metabisulfite+0,1% (TMPC 2: polyacrylate 1, 33% of active substance), drum drying65,16
Drum drying62,28
Air drying64,87

Table 24
Kraft pulp 5, the processed sheets of paper hand reflux, 4 days at 70°C, humidity 100%
No.ResearchWhite 0White TCLoss TC
1Control93,7592,741,01
20.2% of the composition And94,4193,570,84
30.5% of the composition And95,1694,400,76
40.2% composition G94,2393,410,82
50.5% of the composition G94,6894,04 0,64

Table 25
Kraft pulp 5, the processed sheets of paper hand reflux, 4 days at 70°C, humidity 100%
No.ResearchWhite 0White TCLoss TC
1Control93,4292,131,29
20,2% OO94,2092,76the 1.44
30.2% composition A+0,2% OO95,0594,590,46
40.2% composition G+0,2% OO94,8994,390,50
50.5% of the composition G94,5994,170,42

Table 2
Kraft pulp 2, weight 10% concentration, 3 h at 70°C
No.ResearchWhite
1Initial weight (without thermal treatment)88,05
2Control (temperature processing)87,11
30.2% of the composition And87,99
40.2% composition G87,90
50.5% of the composition And87,94
60.5% of the composition G88,47

Table 27
Kraft pulp 2, weight 10% concentration 6 h at 70°C
No.ResearchWhite
1Initial weight (without thermal treatment)88,67
2 Control (temperature processing)87,76
30.2% of the composition And88,31
40.2% composition G88,34
50.5% of the composition And88,61
60.5% of the composition G88,67

Table 12-27 illustrate the application of compositions in which the reducing agent is combined with chelating agents. You can compare different combinations (all effective). The compositions improve long-term stability of the white paper during thermal aging (tables 24-27). This data set also demonstrates the activation of OO in the compositions (tables 12-14, 25). The application of the composition reduces the dosage of the optical Brightener. Tables 16 and 17 illustrate the effect of composition on fluorescence.

5. Application of wet parts: separate introduction of the composition in mass. which leads to the improvement of the properties of OO vs later

The procedure of introducing a lot (80°C) for subsequent amplification steps O.O

Table 28
the raft-cellulose 6
No.% composition%OOWhiteWon numerous. by Rel. control
10086,780,00
200,588,701,92
300,2588,22the 1.44
40,5088,051,27
50,50,591,044.26 deaths
60,500,2589,382,60
70,250,2590,55of 3.77
Table 29
Kraft pulp 6
No.% composition G%OOWhiteWon numerous. by Rel. control
10086,640,00
20,50,591,665,02
30,50,2590,694,05
40,250,2589,322,68
50 0,589,002,36
60,5087,681,04

Table 30
Kraft 6, activation of the optical Brightener, as measured by fluorescence intensity
SampleThe intensity of fluorescence
Control7871
0.5% of the Composition G10370
0,5% OO128578
0.5% of the Composition G then 0,5% OO201199
0.25% of the Composition G then 0,5% OO161354
0.5% of the Composition of G, then the 0.25% OO157359
0.5% of the Composition And, then 0,5% OO191759

Table 28-30 illustrate activation OO by pre-coating composition.

6. Application of wet parts: introduction to composition small the dosage of dithiocarbamato

Table 31
UMM, centrifuge (wet end), application in water
No.% composition% DTKWhiteYellow
10,257%0,0025%79,5311,65
20,257%0,00125%79,7311,93
30,184%0,0025%80,0511,63
40,184%0,00125%79,9811,51
Air drying80,1511,30
Drum drying78,2812,60

Table 32
UMM, the application of surface sizing
No.% HDMI. And% DTKWhite 0Yellowness 0White TCYellow TC% Ing.
10,513%0,0025%79,3512,1677,9112,5627
20,513%0,0050%78,7812,6577,79a 12.750
Drum drying77,912,9275,9313,82

Table 33
Kraft pulp, the application of surface sizing
No.% HDMI. And% DTKWhite 0Yellowness 0White TCYellow TC% Ing.
10,513%0,0025%87,743,9886,244,4631
20,513%0,0050%87,17to 4.5286,274,5458
Drum drying87,643,9285,47of 5.05

Data (tables 31-33) illustrate the recovery of white and long-term stability after the application of the proposed structure.

Although the invention is described above on the basis of typical and are provided to illustrate example implementations, these examples of the invention are not exhaustive and the E. limit the nature and scope of the invention. More specifically, the invention is intended to cover all alternatives, modifications and equivalent solutions, subject to its nature and scope as defined in the attached claims.

1. The method of manufacture of bleached pulp material having high whiteness and high resistance to thermal yellowing, including
i) produce bleached Kraft pulp and
ii) contact bleached Kraft pulp with a sufficient number one
or more reducing agent.

2. The method according to claim 1, further comprising a contact bleached Kraft pulp with one or more optical bleach.

3. The method according to claim 1, further comprising a contact bleached Kraft pulp with one or more chelating agent.

4. The method according to claim 1, where the reducing agent is chosen from the group consisting of sulfites, bisulfites, metabisulfites (pyrosulfite), sulfoxylates, thiosulfates, dithionites (hydrosulfite), polythionates, formamidinesulfinic acid, its salts and derivatives of the adduct of formaldehyde and bisulfite and other adducts of aldehydes and bisulphite, sulfinamides and ethers sulfinol acid, sulfenamides and ethers sultanovoy acid, sulfonamides, phosphines, phosphonium salts, phosphites and thiophosphites.

5. The method according to claim 4, where restoring the Gent is chosen from the group consisting of substituted phosphines, sulfides, bisulfites and metabisulfites.

6. The method according to claim 5, where the reducing agent is a sodium bisulfite.

7. The method according to claim 3, where the chelating agent is selected from the group consisting of organic phosphonates, phosphates, carboxylic acids, dithiocarbamates, salts of all these substances and any combinations thereof.

8. The method according to claim 7, where the chelating agent is selected from the group consisting of diethylenetriaminepentaacetic acid (DMFC) and its salts, diethylenetriaminepentaacetic acid (DPUC) and its salts, and ethylenediaminetetraacetic acid (ETUC) and its salts.

9. The method according to claim 2, where the optical brighteners are selected from desulfurating, tetrasulfonic or hexachlorophene derivatives of stilbene.

10. The method according to claim 1, further comprising a contact bleached Kraft pulp with one or more polycarboxylates.

11. The method according to claim 10, where polycarboxylate is a partially neutralized polyacrylic acid.

12. The method according to claim 1, further comprising a contact bleached Kraft pulp with one or more optical bleach, one or more chelating agent and one or more polycarboxylates.

13. The method according to claim 2, where the reducing agent and optical brighteners mixed with solution for superficial is th sizing and applied to bleached Kraft pulp in size machine.

14. The way to prevent yellowing and loss of white bleached Kraft pulp during storage, including adding in bleached Kraft pulp an effective amount of one or more reducing agent and possibly one or more chelating agent, one or more polycarboxylate or combinations thereof.

15. The method according to 14, where reducing agents and possible chelating agents and polycarboxylate add in bleached Kraft pulp after the stage of bleaching in a collecting pool for the masses, mixing or bypass the pool.

16. A method of manufacturing a paper product having improved whiteness and resistance to thermal yellowing, including
i) produce bleached Kraft pulp;
ii) forming the source water suspension comprising bleached Kraft pulp;
iii) water abstraction from the original suspension with the formation of the sheet, and
iv) drying the sheet,
where in bleached Kraft pulp, the original suspension or sheet add an effective amount of one or more reducing agent.

17. The method according to item 16, further comprising adding a bleached Kraft pulp, the original suspension or sheet of one or more chelating agent, one or more optical bleach and one or more polycarboxylate or combinations thereof.



 

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Paper filler // 2345189

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FIELD: textile, paper.

SUBSTANCE: procedure refers to production of wood pulp and can be implemented in pulp-and-paper industry. The procedure consists in whitening fibres of sulphate pulp with a whitening agent on base of chlorine and in washing whitened fibres of sulphate pulp. Upon washing fibres of sulphate pulp are subject to interaction with at least one optic whitener before mixing ponds. Interacting is carried out in solution at pH from 3.5 to 8.0 and temperature from 60 to 80°C during 0.5-6 hours. The invention also refers to wood pulp produced by the said procedure.

EFFECT: increased whiteness and optic brightness of paper at decreased utilisation of optic whitener.

22 cl, 11 dwg, 11 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: invention relates to concentrated aqueous solutions of hexa-sulfonated stilbene used optical brighteners. Description is given of an aqueous solution of hexa-sulfonated stilbene optical brightener which is stable during storage with over 0.214 mol/kg content thereof in the solution. The solution does not contain a soluble agent, for example urea. By removing salts formed during synthesis of the optical brightener, its concentration of up to 0.35 mol/kg can be achieved without losing stability during storage. Also described is a method of preparing an aqueous solution of the said optical brightener and its use for bleaching paper or cellulose materials.

EFFECT: high concentration solutions of the said optical brightener do not show crystallisation signs after 2 weeks at 5°C and enables formation of coating compositions with low water content, which reduces energy consumption on drying and reduces penetration of water and adhesive into the paper layer.

10 cl, 1 dwg, 1 tbl, 3 ex

FIELD: textile fabrics, paper.

SUBSTANCE: aqueous solutions are related to toluylene optical bleaches and may be used in production of chalk overlay paper of high whiteness. Aqueous solutions contain at least one optical bleach, polyvinyl alcohol, having extent of hydrolysis over 75% and Brookfield viscosity of 2-40 mPa·s, and water. This composition may be used for paper coating. It may be applied on paper after its moulding to produce chalk overlay paper.

EFFECT: provision of stability in storage of aqueous solutions of toluylene optical bleaches and simplified method for production of chalk overlay paper.

9 cl, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: described is a composition, containing (A) 2 to 30 wt % composition of amino alcohol - 2-amino-2-methyl-1-propanol with formula (1), and (B) 70 to 98 wt % composition of fluorescent optical bleaching agent with formula (2) , where X - is hydrogen, ion of alkali metal or ammonium, or hydroxyalkylammonium radical, derived from amino alcohol (1); R7, R8, R9 and R10 - -OR11, -NR11R12 or , where R11 and R12 - is hydrogen, alkyl, hydroxyalkyl, alkoxyalkyl, carboxyalkyl, dicarboxyalkyl, H2N-CO-alkyl or alkylthio group.

EFFECT: high solubility in water and increased stability when storing its aqueous solutions.

4 cl, 3 tbl, 3 ex

FIELD: chemistry, textiles, paper.

SUBSTANCE: present invention relates to new amphoteric bis-triazinylaminostilbene fluorescent whitening agents for fluorescent whitening of organic materials, particularly paper. Description is given of use of compounds with formula (5) for fluorescent whitening of paper.

EFFECT: compounds have high bleaching power; fluorescence is not prevented by cation-active polymers or anion-active fluorescent whitening agents contained in the paper.

2 cl, 2 tbl, 48 ex

FIELD: chemistry.

SUBSTANCE: invention concerns fluorescent bleach containing a mix of two asymmetrically substituted and one symmetrically substituted triazinylaminostilbene disulfone acid, a new symmetrically substituted derivative, method of their obtaining, and application of the mix in synthetic or natural organic material (especially paper) bleaching and in fluorescent bleaching and sun resistance boost of textile.

EFFECT: high substantivity and light resistance of the claimed fluorescent bleaches and their mixes, and better water solubility of the claimed mixes in comparison to the solubility of each individual bleach.

15 cl, 2 tbl, 12 ex

FIELD: organic chemistry, paper industry.

SUBSTANCE: invention relates to compositions used for coating paper covers. Invention describes a composition for coating paper cover comprising whitening pigment comprising: (a) product of melamine formaldehyde or phenol-formaldehyde polycondensation, and (b) water-soluble fluorescent whitening agent of the formula:

wherein R1 and R2 represent independently of one another -OH, -Cl, -NH2, -O-(C1-C4)-alkyl, -O-aryl, -NH-(C1-C4)-alkyl, -N-(C1-C4-alkyl)2, -N-(C1-C4)-alkyl-(C1-C4-hydroxyalkyl)- -N-(C1-C4-hydroxyalkyl)2 or -NH-aryl, for example, anilino-, anilinemono- or disulfonic acid or aniline sulfone amide, morpholino-, -S-(C1-C4)-alkyl(aryl) or radical of amino acid, for example, aspartic acid or iminoacetic acid that is replaced with radical in amino-group; M means hydrogen, sodium, potassium, calcium, magnesium atom or ammonium, mono-, di-, tri- or tetra-(C1-C4)-alkylammonium, mono-, di- or tri-(C1-C4)-hydroxyalkylammonium, or ammonium di- or tri-substituted with a mixture of (C1-C4)-alkyl and (C1-C4)-hydroxyalkyl groups. Covers prepared on coating paper elicit high photostability and enhanced whiteness degree.

EFFECT: improved method for preparing, improved properties of covers.

7 cl, 1 tbl, 3 ex

FIELD: paper-and-pulp industry.

SUBSTANCE: formulation includes optic bleacher and low-viscosity water-soluble nonionic polysaccharide derivative, whose 5% aqueous solution exhibits at ambient temperature Brookfield viscosity below about 1500 cP.

EFFECT: increased brightness of coated paper.

34 cl, 9 tbl, 2 ex

The invention relates to new compounds of the number of 4,4'-diaminostilbene-2,2'-disulfonic acid, which can be used as fluorescent whitening tools

The invention relates to a new method of obtaining compounds distributionally

Paper making method // 2384661

FIELD: textile, paper.

SUBSTANCE: method relates to paper production and can be used in pulp-and-paper industry. Method involves the use of cellulose suspension from cellulose fibres and fillers (optional), dehydration of cellulose suspension on grid or sieve so that a sheet can be formed. Then the sheet is dried. In this method there used is polymeric addition which includes ethylenically unsaturated monomer soluble in water or potentially soluble in water, and ethylenically unsaturated monomer containing a reactive group. The latter represents an epoxy group. The polymeric addition used has molar weight which is less than one million. Polymer is obtained from mixture of monomers, which includes acrylamide and glycidyl methacrylate. Thus, the obtained polymer is used as an addition for increase of paper durability in dry condition, in wet condition, as reagent for internal paper sizing and for surface sizing.

EFFECT: increasing paper durability.

17 cl, 2 tbl, 3 ex

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