RU2386738C2 - Fixation of optic whiteners on fibre - Google Patents

Abstract

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 80C 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

Description

FIELD OF TECHNOLOGY

The present invention relates to a method for increasing the optical brightness of wood pulp, to wood pulp made by such methods, and to methods of using such wood pulp.

BACKGROUND

Whitening is a common way to increase the whiteness of wood pulp. The industry practice of improving the appearance of fluff pulp is to bleach it to even higher levels of optical brightness (TAPPI Technical Association or the International Organization for Standardization ("ISO"). However, bleaching is a costly, environmentally disadvantageous process and often causes a bottleneck in production. Consumers' widespread preference for brighter and whiter paper is forcing manufacturers to use even tougher whitening strategies. Although wood pulp with a high degree of whitening is “whiter” than wood pulp with a lower degree of whitening, it is still yellowish white in color. A yellowish white product is undesirable. Numerous studies suggest that consumers clearly favor bluish white over yellowish white. The former is perceived as whiter, that is, “fresh”, “new” and “clean”, and the latter is considered “old”, “faded” and “dirty”.

Although whitening directly increases optical brightness, it only indirectly increases whiteness. As a result, bleaching is not always the most effective way to enhance the whiteness of paper. For example, even after aggressive whitening, the whiteness of a product can always be increased by the reasonable addition of pigments compared to the degree achievable with whitening alone.

The practice of pre-tinting wood pulp for making paper is usually not used, and it is not necessarily desirable. In the first case, a deliberate change in optical properties often leads to degradation of product characteristics, such as the optical brightness of TAPPI, which is undesirable. In the second case, there is a risk that the pigments may not withstand unpredictable production conditions in subsequent stages. The reason for this is that the pre-added pigment can have an adverse chemical and / or physical effect in subsequent operations, which will lead to an unexpected or undesirable change or even complete loss of color. In addition, some pigments may be lost or become ineffective in various subsequent operations, violating the integrity and reliability of the process. Therefore, any optical improvement is usually achieved by the addition of tinting pigments, fillers and / or luminescent dye at the paper manufacturing stage. A method of increasing the whiteness, optical brightness and color of fibers for making paper is described in US Pat. No. 5,482,514. This method relates to the addition of photoactivators, in particular water-soluble phthalocyanines, to fibers for making paper in order to improve their optical properties by the method of catalytic bleaching with a photosensitizer. The resulting bleached fibers for making paper can be successfully incorporated into paper sheets.

For fluff pulp, as well as for most pulp and paper products, TAPPI optical brightness is actually the standard instead of industry-specific whiteness characteristics such as CIE (Commission Internationale d'Eclairage). As a result, optical brightness plays two main roles. First, optical brightness is a production parameter. Secondly, optical brightness is a technical characteristic for the classification of varieties of final products. An implied, though dubious, assumption to date is that optical brightness is equivalent to whiteness. It is common practice for paper to add either blue tinting dyes, or tinting pigments, and / or various types of blue-violet fluorescent dyes to enhance whiteness. Tinting dyes are either finely ground colored pigments suspended in a dispersant or synthetic direct dyes. Tinting dyes have some affinity for cellulose fibers, while tinting pigments have practically no.

Luminescent brighteners (LO) or optical brighteners (OO) used in the pulp and paper industry are of three types: di-, tetra- or hexasulphonated stilbene compounds, for example. These chemicals require ultraviolet (UV) radiation to excite luminescence. Although daylight has a high UV content, even ordinary office lighting creates sufficient UV radiation to initiate some excitation.

In the manufacture of papermaking, OOs are used at the wet stage of papermaking processes that use, for example, a pool mixer and / or a vane pump, if the fibers in the solution have a low consistency, less than about 3% solids. In these traditional places of addition, most of the OO goes to waste, since OO does not necessarily have a strong affinity for the fibers in solution. Accordingly, OO must be added in high concentrations (pounds per tonne of fiber or wood pulp) in order to obtain high quality fibers having a high degree of optical brightness and a high degree of improvement in optical brightness.

Accordingly, there is a need for wood pulp having enhanced whiteness and optical brightness. There is also a need for a method of producing wood pulp with increased whiteness / optical brightness for any application, especially in wood pulp for making paper and in fluff pulp, using less OO in order to obtain such levels of whiteness and optical brightness at lower cost. The present invention addresses these needs and has further related advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 - graphs of the optical brightness of ISO against the level of OO in the sheets of manual casting made of wood pulp processed OO, a complete set of data.

Figure 2 - graphs of the optical brightness of ISO against the level of OO in the sheets of manual casting made of wood pulp processed OO, a set of data on the dose.

Figure 3 - graphs of the optical brightness of ISO against the level of OO in the sheets of manual casting made of wood pulp treated OO, the dose of OO in the presence of 10% and 20% filler.

Figure 4 - graphs of the optical brightness of ISO against the level of OO in the sheets of manual casting made of wood pulp treated OO, the effect of the dose of OO in the presence of 10% and 20% of the filler, added regression lines.

Figure 5 - Raman spectra of only OO and wood pulps with different levels of OO added by known methods.

6 is a Raman spectra of wood pulp with different levels of OO0 added according to one aspect of the present invention.

7 is a Raman spectra of wood pulp with different levels of OO added according to known methods and added according to one aspect of the present invention.

Fig. 8 is a graph of peak ratios (1604/900 cm ^-1 ) in the Raman spectra of wood pulp with different levels of OO added by known methods and added according to one aspect of the present invention (hardwood and softwood pulp) according to table 10.

Fig.9 - UV / VID absorbance at 350 nm of an aqueous extract against the actual amount of OO on the fibers, in pounds per ton.

Figure 10 is the peak height of the OO versus the amount of OO added (pounds per ton) according to the known addition method and according to one aspect of the present invention (hardwood and softwood pulp).

11 is the peak height of the OO versus the amount of OO added (pounds per ton) by the conventional addition method and in accordance with one aspect of the present invention (hardwood and softwood pulp).

DETAILED DESCRIPTION OF THE INVENTION

The inventor of the present invention unexpectedly discovered a method for effectively increasing the optical brightness and whiteness of wood pulp and paper using less OO and at the same time providing a much higher efficiency of forming a fiber-OO complex with increased interaction between fiber and OO than in the known methods of forming a fiber-OO complex . Such a fiber-OO complex obtained by the method according to the present invention has a greater increase in optical brightness and whiteness than a single fiber compared to known methods described below.

The present invention relates in part to a method for making wood pulp. The pulp may be fluff or pulp for paper production. This method can be used in addition to any known methods for making fluff pulp or pulp for paper production. Pulp can be used for any known application, including any known methods for the production of paper and / or cardboard substrates. Such well-known methods of making wood pulp and paper can be found, for example, in "Handbook For Pulp & Paper Technologies" {Pulp and Paper Technology Guide), 2nd Edition, G.A. Smook, Angus Wilde Publications (1992) and the references cited therein, which are incorporated herein by reference in their entirety.

A typical method of manufacturing wood pulp / paper may include, without limitation, the following steps:

A. The step of cooking wood chips to separate cellulosic fibers from lignin.

B. The washing step from the cooking liquor, in which the pulp is washed after the cooking step.

C. Bleaching / extraction steps in which pulp is recovered and bleached using various chemicals, such as oxygen during oxygen delignification, chlorine dioxide, elemental chlorine, peroxide, ozone, etc., followed by one or more washing steps .

D. A high density storage step wherein the bleached / washed pulp is stored at a relatively high density, for example greater than about 7%, preferably from about 7.5% to 15%, and more preferably from about 10% to 12%.

E. A low density storage step wherein the bleached / washed pulp is stored at a relatively low density, for example equal to or less than about 7%, preferably from about 3% to 7%, and more preferably from about 10% to 12%.

D. The stage of refinement, in which the pulp is ennobled with a consistency of from about 4% to 5%.

E. Stages of mixers in which a pulp having a consistency of preferably from about 3% to 4% is mixed with wet chemicals used in the manufacture of paper, such as fillers, retention agents, colorants and optical brighteners, etc. Such known methods may include re-conducting any one or more of the above steps. In addition, the present invention can be combined with known methods for adding OO to fibers, for example, at conventional wet addition points and coating addition points in the manufacture of paper and / or paperboard.

The present invention relates in part to a method for adding OO to fibers at any point after the last bleaching / extraction step before the mixer steps.

The source of fibers can be any fibrous plant. The paper base may contain recycled fibers, bleached fibers and / or natural fibers. Examples of such fibrous plants are trees, including deciduous and coniferous trees, and also mixtures of their fibers. In some embodiments, at least a portion of the cellulosic fibers can be obtained from non-woody herbaceous plants, including without limitation kenaf, hemp, jute, flax, sisal and abacus, although legal restrictions and other considerations may make the use of hemp and other fiber sources impractical or impossible . Bleached or unbleached cellulose fibers may be used in the method of the present invention. Recycled cellulose fibers are also suitable.

The wood pulp of the present invention may contain from 1 to 99 wt.%, Preferably from 5 to 95 wt.%, Cellulose fibers of hardwood and / or conifers from the total volume of cellulose fibers. This range includes 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100 wt.%, including any ranges and subranges in it, of the total volume of cellulose fibers.

If the wood pulp may contain deciduous and coniferous fibers, it is preferred that the ratio of deciduous / coniferous fibers is from 0.001 to 1000. This range may include 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0, 1, 0.2, 0.5, 1, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500, 600, 700, 800, 900 and 1000, including any ranges and subranges in it and the reciprocal of such relations.

Optical brighteners are luminescent compounds such as dyes that absorb shortwave ultraviolet radiation that is not visible to the human eye and emit longer wavelength blue light, with the result that the human eye perceives a higher degree of whiteness, thereby increasing the degree of whiteness. Optical brighteners used in the paper industry are usually 1,3,5-triazinyl derivatives of 4,4'-diaminstilbene-2,2'-disulfonic acid, which may have additional sulfo groups, for example only 2, 4 or 6. An overview of such brighteners can be found, for example, in Ullmann's Encyclopedia of Industrial Chemistry. Sixth Edition, 2000 Electronic Release, optical brighteners - Chemistry of technical products. However, new types of bleaches are also suitable, for example derivatives of 4,4'-distyryl biphenyl, similar to those described in the aforementioned Ullmann's Encyclopedia of Industrial Chemistry, which is incorporated herein by reference in its entirety. Although fiber-OO methods and complexes using the aforementioned OO are preferred in the present invention, the present invention is in no way limited to such illustrative embodiments, and any 00 may be used in it.

The present invention relates in part to a fiber-OO complex in which the affinity of the OO added to the fiber according to the present invention is greater than in cases where the OO is added to the fiber by known methods. If OO is added to the fiber according to the method of the present invention, it is necessary to add OO in an amount of 30-60% less than in known methods and points of addition. The reduction in the amount can be 30, 31, 32, 33, 34, 35, 40. 45, 50, 55, 56, 57, 58, 59 and 60% compared with the amount required in the known methods and points of addition, including any ranges and subbands within these limits.

The increased affinity of OO with fiber can be measured by extraction methods using any solvent, preferably water, at any temperature. Since OO has an increased affinity for fiber in general, in the wood pulps and paper substrates of the present invention, it will take longer to extract OO from the OO-wood pulp complex of the present invention for a specific period of time and temperature for a particular solvent.

In addition, the present invention preferably relates to a method for increasing the penetration of OO into the walls of fiber cells. Preferably, more OO penetrates into the cell walls of fibers treated according to the present invention than fibers treated by known methods. More preferably, the amount of OO present in the cell walls of the fibers will increase by at least 1% compared to the amount of OO present in the cell walls of the fibers treated by known methods. However, it is more preferred that the amount of OO present in the cell walls of the fibers increases by at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100, 200, 300, 500 and 1000% compared with the amount of OO present in the cell walls of fibers treated by known methods, including any ranges and subranges within these limits.

The amount of OO present in the cell walls of the fibers can be measured, for example, by microscopy, more specifically by luminescent microscopy.

Although any amount of OO can be added to the fiber since it is added at any point after the last bleaching / extraction step to the mixer stage, it is preferable to add 1 to 60 pounds of OO per ton of fiber, more preferably not more than 30 pounds per ton, most preferably not more than 15 pounds of OO per ton of fiber. This range includes 60, 55, 50, 45, 40, 30, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 and 1 pound OO per tonne of fiber, including any ranges and subranges within these ranges.

In addition, the fiber may be in solution or be added to the solution simultaneously with OO. Preferably, the fiber is in solution until the OO contacts it. In one embodiment of the present invention, the fiber may have any consistency. However, it is preferred that the solids consistency is equal to or greater than 4%, more preferably not less than about 5%, most preferably not less than about 10%. In addition, it is preferable that the fibers have a solids consistency of not more than about 35%, more preferably not more than 20%, most preferably not more than about 15%. These ranges include solids consistencies of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20% when adding OO to the fiber , including any ranges and subranges within these limits.

During the addition of OO to the fiber, the pH value can be any. Preferably, the pH may be from 2.5 to 8.0, more preferably from 3.5 to 5.5. This range includes values of 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5 and 8, 0, including any ranges and subranges within these limits.

During the addition of OO to the fiber, the temperature can be any. However, it is preferable to use means, such as heating means, to create a temperature of from 35 to 95 ° C, preferably from 50 to 90 ° C, more preferably from 60 to 80 ° C. This range includes 35, 40, 45, 50, 55, 60, 61, 62, 63, 64, 65. 66. 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78 , 79, 80, 85, 90 and 95 ° C, including any ranges and subranges within these limits.

The contact time of the OO with the fiber can be any. Preferably, the OO and the fiber can be contacted from 30 minutes to 12 hours, more preferably from 45 minutes to 8 hours, most preferably from 1 hour to 6 hours. This range includes 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3 , 75, 4, 4.25, 4.5, 4.75, 5, 5.25, 5.5, 5.75, 6, 6.5, 7, 7.5, 8, 8.5, 9 , 9.5, 10, 11 and 12 hours, including any ranges and subranges within these limits.

During contact of the OO with the fiber, retention aids may optionally be added or present. Examples of such retention aids are alum and / or cationic retention aids. Examples of retention aids can be found in provisional patent application US 60/660703, filed March 11, 2005, and in US patent No. 6,379,497, which are fully incorporated herein by reference. However, any restraint may be used. commonly used with OO. Although the retention aid may be present in any amount or not present at all, it is preferable that the amount of retention aid present is less than that required by known methods and points of addition upon contact of the OO with the fibers. Most preferably, retention aids are not used. If a retention aid is used, it is preferable that the amount of the retention aid is reduced by at least 1% compared to known methods and points of addition at the contact of the OO with the fibers. Preferably, the reduction in the amount of retention aid is at least 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 75, 100, 200, 300, 500 and 1000% compared with known methods and points of addition at the contact of the OO with the fibers, including any ranges and subranges within these limits.

Although the fiber can be ennobled at any time, preferably the fiber is ennobled after the contact of the OO with the fiber. Therefore, the fiber-OO complex of the present invention is ennobled. Accordingly, any known refinement can be carried out, including, without limitation, chemical refinement, mechanical refinement, thermochemical refinement, thermomechanical refinement, chemical thermomechanical refinement, etc. Therefore, the resulting wood pulp may contain thermomechanical cellulose, chemical thermomechanical cellulose, mechanical cellulose, bleached chemical thermomechanical cellulose, etc.

The wood pulp of the present invention and its production method can be included in any known paper manufacturing method. The wood pulp and / or paper base may also contain other known additives, such as, for example, starch, mineral and polymer fillers, adhesives, retention agents and hardening polymers. Fillers that can be used include organic and inorganic pigments, such as, for example, minerals, such as calcium carbonate, kaolin and talc, as well as expanded and expandable microspheres. Other known additives include, without limitation, moisture resistant resins, internal adhesives, dry resins, alum, fillers, pigments and dyes. Particularly preferred dyes are blue, which are able to enhance the whiteness of CIE wood pulp and / or paper base. Preferably, the wood pulp and paper base of the present invention obtained according to the present invention are able to achieve a CIE whiteness that is much higher than that of known wood pulps and substrates obtained by known methods, even at CIE whiteness levels that typically result in lower optical brightness levels ISO

The wood pulp and / or paper base of the present invention can have any CIE whiteness, but preferably has a CIE whiteness of greater than 70, more preferably greater than 100, most preferably greater than 125, or even greater than 150. The CIE whiteness can be in the range of 125 to 200, preferably from 130 to 200, most preferably from 150 to 200. The CIE brightness range may be equal to or greater than 70, 80, 90, 100, 110, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195 and 200, including any ranges and subranges within these ranges. Examples of measuring CIE whiteness and achieving such whiteness of fibers and paper made from them can be found, for example, in US Pat. No. 6,893,473, which is incorporated herein by reference in its entirety.

Preferably, the wood pulp and / or paper base of the present invention has a CIE whiteness that is higher than that of known wood pulps and / or paper substrates obtained by known methods. Preferably, the increase in CIE Whiteness is at least 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 75, 100, 200, 300, 500, and 1000% compared with known wood pulps, paper substrates obtained by known methods and at known points of addition at the contact of the OO with the fiber, including any ranges and subranges within these limits.

The wood pulp and paper base of the present invention can have any ISO optical brightness, but preferably greater than 80, more preferably greater than 90, most preferably greater than 95. The ISO optical brightness can preferably be from 80 to 100, more preferably from 90 to 100, most preferably from 95 to 100. This range includes ISO optical brightness values equal to or greater than 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, and 100, including any ranges and subranges within these ranges. Examples of measuring ISO optical brightness and achieving such brightness in pulp for making paper and paper made from it can be found, for example, in US Pat. No. 6,893,473, which is incorporated herein by reference in its entirety.

Preferably, the wood pulp and / or paper base of the present invention has an optical brightness of ISO that is higher than that of known wood pulps and / or paper substrates obtained by known methods.

The preferred increase in ISO brightness is at least 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 75, 100, 200, 300, 500 and 1000% compared with brightness known wood pulps, paper substrates obtained by known methods and at points of addition at the contact of the OO with the fiber, including any ranges and subranges within these limits.

The present invention is described in more detail using the following example embodiment, which is not intended to limit the scope of the present invention in any way.

EXAMPLES

COMPARATIVE EXAMPLE 1

Laboratory experiments were conducted to simulate commercial paper manufacturing operations, during which a Clariant T-100 tetrasulfonated OO was added to three samples of bleached hardwood sulphate pulp. For mixing wood pulp with all chemicals used a laboratory mixer "Warring" with a low speed. Before adding optical brightener (OO), deionized water was added to a sample of wood pulp of kiln drying with a mass of 5 g to reduce its consistency to 1%. Shortly after the addition of OO, 5 ml of a 5% alum solution was added to the wood pulp mixture to complete fixing all OO to the fiber. After stirring in the mixer for 1 min, the pulp mixture was dehydrated to obtain a sample for measuring brightness according to the standard Tappi procedure for checking optical brightness. Three wood pulp samples and three doses of T-100 were used in these experiments. The results of measuring the brightness of individual samples of wood pulp before and after fixation of OO are as follows.

Table 1 Sample 1 Sample 2 Sample 3 Brightness (GE) Brightness boost Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 80.5 0 84,4 0 86.6 0 four 83.1 2.6 87.7 3.3 90.0 3.5 8 84.2 3,7 89.7 5.1 90,4 3.8 16 84.9 4.3 89.4 5,0 90.7 4.1

COMPARATIVE EXAMPLE 2

Laboratory experiments were conducted to simulate commercial paper manufacturing operations, during which a Clariant T-100 tetrasulfonated OO was added to a single sample of bleached southern hardwood sulphate pulp. To mix wood pulp with all chemicals, a Warring low-speed laboratory mixer was used. Before adding optical brightener (OO), deionized water was added to a sample of wood pulp of kiln drying with a mass of 5 g to reduce its consistency to 1%. In series I experiments, shortly after the addition of OO, 5 ml of a 5% alum solution was added to the wood pulp mixture to complete fixing the entire OO to the fiber. In experiments of series II, alum was not used. In both cases, after stirring in the mixer for 1 min, the pulp mixture was dehydrated to obtain a sample for measuring brightness according to the standard Tappi procedure for checking optical brightness. Three wood pulp samples and three doses of T-100 were used in these experiments. The results of measuring the brightness of individual samples of wood pulp before and after fixation of OO are as follows.

table 2 Episode I - Without Alum Episode II - With Alum Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 84.0 0 84.0 0 3 87.4 3.4 6 89.0 5,0 10 89.7 5.7 twenty 85.8 1.8 89.1 5.1 40 86.4 2,3 86.2 2.1 60 86.7 2.7 82,2 1.8

Table 3 Episode I - Without Alum Episode II - With Alum Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 84.0 0 84.0 8 3 87.4 3.4 b 89.0 5,0 10 89.7 5.7 twenty 85.8 0.8 89.1 5.1 40 86.4 2,3 86.2 2.1 60 86.7 2.7 82,2 1.8

Table 4 Water bath at 60 ° C Water bath at 75 ° C The number of T-100 Reaction time (h) Brightness (GE) Brightness boost Brightness (CE) Brightness boost 0 0 88.9 0 88.9 0 2 one 93.0 4.1 91.8 2.9 four one 93.6 4.6 93,4 4,5 8 one 94.9 6.0 94.7 5.8 0 0 88.9 0 88.9 0 2 5 92.2 -3.3 92.0 3,1 four 5 93.6 4.6 92.7 3.8 8 5 94.0 5.1 93.9 4.9

EXAMPLE 2

Samples of fully bleached hardwood and softwood sulphate pulp were taken at the outlet of the bleaching plant of a commercial pulp and paper mill in the southern United States and were used for experiments on the fixation of high concentration OO. The experimental conditions, including the type of OO and the consistency of wood pulp, were similar to those described in Example 1. The resulting sample of coniferous wood pulp had a pH of 5.2, hardwood pulp - 6.7. Each experiment was carried out for two hours, in a bath with a temperature of 65 ° C. Before some experiments with hardwood pulp, a dilute hydrochloric acid solution was added to the resulting pulp to lower the pH to 4.9 during the reaction with OO. The following results were obtained.

Table 5 Count T-100 (pounds per tonne) Conifer. other mass at 5.2 Sheet. other mass at 6.7 Sheet. other mass at 4.9 Brightness (GE) Brightness boost Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 85.5 0 85.6 0 85.6 0 2.5 89.4 3 87.5 1.9 90.1 4,5 5,0 89.7 four 88.5 2.9 91.3 5.7 10 91.2 5 89.3 3,7 fifteen 91.5 6 90.2 4.6 92.4 6.8

EXAMPLE 3

Samples of fully bleached hardwood and coniferous wood pulp were taken at the outlet of the bleaching plant of a commercial pulp and paper mill in the southern United States and were used for OO fixation experiments. The pH of the filtrate of both wood pulp samples was 3.0. In this example, a disulfonated OO "Leucophor ANO" company Clariant. Fixation experiments were carried out with different amounts of added OO, with a consistency of 10%, for two hours in a bath with a temperature of 65 ° C. As a result of OO fixation, the following changes in the brightness of the wood pulp were observed.

Table 6 Count Leucophor (pounds per tonne) Deciduous wood pulp Coniferous pulp Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 89.3 0 88.4 0 5 93.6 4.3 92.8 4.3 10 94.3 4.9 92.1 3,7 fifteen 92.7 3.4 90,4 2.0 twenty 91.9 2.6 89.6 1,1 thirty 89.3 0 86.0 -2.5

EXAMPLE 4

Samples of wood pulps and OO from Example 3 were used in this example. However, before mixing OO, a dilute NaOH solution was used to increase the pH of the samples from 3.0 to 5.7 for deciduous wood pulp and up to 7.0 for coniferous wood pulp. All other conditions were similar to those of Example 4. As a result of pH adjustment and OO fixation, the following changes in the brightness of wood pulp were observed.

Table 7 Count Leucophor (pounds per tonne) Deciduous wood pulp Coniferous pulp Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 89.0 0 87.9 0 four 93,4 4.4 92.5 4.6 8 94.9 5.8 93.8 5.9 12 95.1 6.3 94.0 6.1 twenty 95.5 6.5 94.8 6.8 thirty 89.3 6.6 95.1 7.2

EXAMPLE 5

T-100 fixation experiments were carried out on commercial fully bleached softwood and hardwood sulfate pulp samples from a pulp and paper mill in the northern United States. The softwood pulp had a grinding degree of 690 csf, an optical brightness of 90 GE and a pH of 4.0. The hardwood pulp sample had a grinding degree of 570 csf, an optical brightness of 89.2 and a pH of 4.0. Different doses of T-100 were mixed with pulp at a consistency of 10% and the samples were stored in separate sealed plastic bags. The bags were placed in a water bath with a temperature of 70 ° C for 2 hours. Changes in the brightness of individual samples of wood pulp as a result of OO fixation were as follows.

Table 8 Count Coniferous pulp Deciduous wood pulp T-100 (pounds per tonne) Brightness (GE) Brightness boost Brightness (GE) Brightness boost 0 90.0 0 89.2 0 2 94.4 4.4 92.0 2,8 four 95.2 5.2 92.7 3,5 b 95.8 5.8 93.3 4.1 8 96.3 6.3 93.8 4.6 10 96.6 6.6 94.2 5,0 12 97.1 7.1 94.3 5.1

EXAMPLE 6

The untreated samples of coniferous and deciduous wood pulp from Example 5, together with samples fixed with T-100 in the amount of 12 pounds per tonne, were subjected to high shear force in the laboratory refiner "PFI". The degree of refinement of the pulp was controlled so that the grinding degree of the coniferous pulp was reduced from 690 CSF before the refinement to 450 CSF after the refinement. Deciduous wood pulp was reduced from 570 CSF to 330 CSF. As a result of the refinement of untreated samples and samples containing OO, the changes in brightness were as follows.

The loss in brightness resulting from the refinement of wood pulp is well known in paper production. Under conditions of refinement in example 6, it amounted to 1.6 points for untreated coniferous wood pulp and 0.8 points for untreated deciduous wood pulp. The loss of brightness was very similar for the case when the wood pulp was mixed with OO, which suggests the strength of the created bond between the OO and the fiber, which was not affected by the mechanical shear force in the refiner. The net increase in brightness as a result of OO fixation remained essentially unchanged; the refinement of the pulp did not affect it.

EXAMPLE 7

Examination of sheets of manual casting

Summary

A study of hand-cast sheets confirmed that the addition of Clariant's Leucophor ANO Optical Brightener (OO) using the high consistency processing method yields increased brightness compared to the addition of OO at low consistency.

For a fixed dose, a new addition point led to an increase in brightness of approximately 1.9 units of ISO optical brightness.

Based on the data from this study, in order to achieve the same degree of optical brightness of ISO when applying the new addition method, the dose of OO is reduced by 3.5 pounds per ton.

These estimates are based on OO dose levels of 3.3 to 10 pounds per ton. The experiment proved that two factors, namely the dose of OO (nominally 3.3 and 10 pounds per tonne) and the method of adding OO (a new method against adding low consistency to wood pulp), were statistically significant in determining the brightness.

experimental part

1. Wood pulp

For this study, unbleached deciduous and coniferous pulp from the wash basin of the last stage of bleaching was used.

2. Fixing OO

Deciduous pulp and coniferous pulp separately with two quantities of OO - 3.3 and 10 pounds per ton. As OO, Leucophor ANO (Clariant company), which is a disulfonated OO, was used. The following conditions were taken: consistency 10%, stirring for 2 hours at 70 ° C.

3. Improvement

Before ennobling, the pulp was mixed in a ratio of 70:30 (deciduous: coniferous). The refinement was carried out in a laboratory disk refiner LR1. Two energy values of 35 kW / t and 45 kW / t were used. The degree of grinding of the resulting wood pulp was ~ 580 and ~ 320 csf, respectively.

4. Sheet making

Sheets were made on a dynamic casting machine in the following way. The pulp was diluted to a consistency of 1% with vigorous stirring. First, calcium polycarbonate (PAC) “Albacar LO PCC” of SMI was added and mixed for 1 min. Then, a certain and accurately measured amount of OO was added and mixed for 15 minutes. Then the sheet was molded. After molding, the sheets were pressed to a solids content of ~ 45% and dried at a temperature of 230 ° F on a drying cylinder. Special precautions have been taken to ensure that sheets with a "fixed" TOE have quantities of TOE that are similar to standard sheets with added TOE. In addition to samples pretreated by OO and samples prepared as described above, where PAC was added before OO, several control samples were made for which the order of adding PAC and OO was changed (OO was added first).

5. Tests

Sheets were tested for various optical properties using a DataColor Eirepho spectrophotometer.

6. Experiment Plan

The design of this experiment took into account four main factors:

I) the consistency of the mass to which OO was added (10% versus 1%);

II) refinement (35 kW / t vs. 45 kW / t);

III) filler content (10% vs 20%);

Iv) a dose of OO (3.3 vs 10 pounds per ton).

Results and Conclusions

Comparison of the brightness of sheets of manual castings obtained by new and known methods

The addition of Clariant Leucophor ANO Optical Brightener (00) with the new high consistency treatment method yielded higher brightness than the low consistency addition for manual casting sheets. These results are shown in FIGS. 1-4, where all of the brightness data are plotted against the dose of the TO. Several different classes of samples are given, separated by fixation method (at high and low consistency) and filler content (10 and 20 pounds per ton).

The study of wood pulp with OO by Raman spectroscopy

Raman spectroscopy was used to study wood pulp with OO added according to a known and new methods. Figure 5 shows a comparison of the spectrum of OO (Leucophur ANO) with the spectra of wood pulp with added OO and without OO. The most intense peak in the OO spectrum at approximately 1600 cm ^{-1 is} visible in the wood pulp spectrum with added OO. Figure 6 shows the spectra of wood pulp (extended range from 300 to 1700 cm ^-1 ) with different content of added OO. The peak intensity at 1600 cm ^-1 increased with increasing OO content. When comparing the spectra of wood pulp with OO added according to the known and new methods, there were no changes in the shape of the peaks or additional peaks (see Fig.7). To determine the relative amount of OO fixed to the fibers, we calculated the ratio of the maximum intensity at 1600 cm ^-1 to the peak intensity at 900 cm ^-1 (cellulose peak) for wood pulps with different contents of added OO. The results are presented in the table and in Fig.8.

TABLE 10 Way The number of added OO, pounds per ton Peak Height Ratio Famous 0 0,026 10 0.469 fifteen 0.637 twenty 0.711 New (deciduous dr. Mass) 0 0,034 3.3 0.238 10 0.648 New (coniferous dr. Mass) 0 0,071 3.3 0.371 10 0.685

The results of Raman scattering measurements show that the amount of OO in the wood pulp obtained according to the method of the present invention is comparable to the amount of OO in the wood pulp obtained in a known manner with an amount of OO of 15-20 pounds per ton.

The study of OO in wood pulp by the method of spectroscopy with induced plasma (SIP)

Samples of coniferous and deciduous wood pulp with added OO according to the known and new methods were hydrolyzed on a hot plate using hydrogen peroxide and nitric acid. A sample of OO used in a particular method was dried and hydrolyzed under the same conditions. Hydrolyzed samples were analyzed for sulfur content by SIP. The results are presented in table 11. The untreated wood pulp was also analyzed under the same conditions and the measured sulfur content was subtracted from the content in the treated wood pulp in order to establish the amount of OO present in the wood pulp to obtain the dry mass of OO.

Table 11 Way Added OO, pounds per ton SIP sulfur, parts per million OO sulfur on fiber, ppm Sulfur on fiber, ppm (sulfur results) Famous 0 150 10 190 40 697 twenty 250 one hundred 1744 New (deciduous dr. Mass) 0 140 10 250 110 1918 New (coniferous dr. Mass) 0 140 10 150 84 1465 OO (kiln drying) 57600; 57100

The sulfur concentrations in the wood pulp show that the amount of OO present in the wood pulp treated by the method of the present invention at 10 pounds of OO per ton is comparable to the amount of OO in the wood pulp obtained in a known manner at 20 pounds per ton.

Extraction studies

About 1 g of wood pulp was cut into small pieces and soaked in approximately 150 ml of water for 6 hours at a temperature of 60 ° C.

The aqueous extracts were filtered through a 0.45 μm filter and recovered to a volume of approximately 2 ml in a LABCONCO Rapidvap nitrogen evaporation system using air as purge gas. The evaporator operated at a vortex rate of 24% at a temperature of 30 ° C. After evaporation to approximately 2 ml, the sample was transferred to a 5 ml volumetric flask.

A portion of this amount of 5 ml of the aqueous extract was analyzed by high performance liquid chromatography (HPLC).

A portion of this amount of 5 ml of the aqueous extract was diluted 1:10 for UV / VIS analysis.

Characteristics of equipment for ghvr

Description of the device: separation unit "Waters Alliance 2695" with a matrix photodiode detector model "Waters 996".

Mobile phase: 50% methanol, 50% PIC-A buffer solution at 0.7 ml / min. PIC-A is sold by Waters Corporation and is a reversed-phase ion exchange chromatography buffer containing 0.005 M tetrabutylammonium phosphate adjusted to pH 7.5.

Column: Phenomenex Luna 5 μm C-8 (2) 250 mm × 4.6 mm, operation at 35 ° C.

Detector: matrix photodiode detector "Waters 400" for the range of 200-800 nm. A peak at 254 nm was selected for analysis.

The process time is 60 minutes

The volume of input is 10 μl.

UV / VIS Equipment Specifications

Description of the device: Shimadzu UV-160 model operating in photometric mode.

The wavelength used for analysis is 350 nm.

The results are shown in Fig.9-11.

In light of the above description, numerous modifications and changes are possible. Therefore, it is understood that, within the scope of the appended claims, the invention may be practiced differently than described herein.

The ranges indicated herein are used as a short name to describe any and every value included in it, including all subranges.

All references, as well as the references mentioned therein, are incorporated herein with respect to its specific parts relating to the subject of the present invention and all variants of its implementation.

Claims (22)

1. A method of manufacturing wood pulp, comprising bleaching a plurality of sulphate pulp fibers with a chlorine-based bleaching agent, washing a plurality of bleached sulphate pulp fibers after bleaching, and at the end of the washing, reacting the sulphate pulp fibers in solution at a pH of from 3.5 to 8.0 and at a temperature from 60 to 80 ° C for from 0.5 to 6 hours with at least one optical brightener before the mixer pool stage. 2. The method according to claim 1, where after washing the specified interaction is carried out in solution at a pH of from 3.5 to 5.5. 3. The method according to claim 1, where the consistency of the fibers in the solution is more than 4%. 4. The method according to claim 1, where the consistency of the fibers in the solution is from 7 to 15%. 5. The method according to claim 1, where the optical brightener in an amount of from 1 to 15 pounds per ton interacts with the fibers. 6. The method according to claim 1, where the interaction occurs at a point in the implementation of the method of manufacturing wood pulp or paper manufacture to the stage of refinement. 7. The method according to claim 1, where the specified interaction occurs without a retention aid. 8. The method according to claim 1, which further includes the interaction of an additional bleach with fibers during operation of the sprayer. 9. The method according to claim 1, which further includes the interaction of an additional bleach with fibers during the size press. 10. The method according to claim 1, where the consistency of the fibers in the solution is from 10 to 12%. 11. The method according to claim 1, wherein the plurality of bleached sulphate pulp fibers in solution has an ISO brightness of less than 90 before the plurality of sulphate pulp fibers in solution is mixed with at least one bleach and the ISO brightness is greater than or equal to 90 after the plurality of sulfate pulp fibers reacts in solution with at least one bleach. 12. The method according to claim 1, wherein the plurality of bleached sulphate pulp fibers in solution has an ISO brightness of less than 90 before the plurality of sulphate pulp fibers in solution is mixed with at least one bleach and the ISO brightness is greater than or equal to 92 after the plurality of sulphate pulp fibers reacts in solution with at least one bleach. 13. The method according to claim 1, where the fiber sulfate cellulose obtained from hardwood. 14. The method according to claim 1, where the fiber sulfate cellulose obtained from conifers. 15. Wood pulp obtained by the method according to claim 1. 16. The wood pulp according to clause 15, where the wood pulp is fluff pulp. 17. Wood pulp according to clause 15, where the wood pulp is wood pulp for paper production. 18. The wood pulp according to clause 15, which has an optical brightness of ISO not less than 90. 19. The wood pulp according to clause 15, which has an optical brightness of ISO not less than 95. 20. Wood pulp according to clause 15, which has an optical brightness of ISO not less than 98. 21. The wood pulp according to clause 15, which has a CIE whiteness of not less than 130. 22. Wood pulp according to clause 15, which has a CIE whiteness of at least 130 and an optical brightness of ISO of at least 90.

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