SU834292A1 - Paper manufacturing method - Google Patents

Description

(54) METHOD OF MANUFACTURING PAPER

The invention relates to the production of paper types filled with paper and can be used in the manufacture of high-grade paper types, which are subject to increased requirements for optical and color properties, mainly printed paper types. Nowadays, highly filled paper types, preferably printed (gravure, offset, printing, etc.), are produced. With a high ash content (15-35%), the paper should simultaneously have increased mechanical strength, high whiteness, and uniform color on the sides of the pst. This requires the use of several components at once, which give the paper the desired properties: high molecular weight anionic and nonionic polymers, optical brighteners, organic dyes, and pigments. A known method of manufacturing highly filled paper types, in which, in order to better hold various fillers and small flocculants, is introduced into the pulp just in front of the paper machine, preferably in a pressure box II. With a combination of different floccuts, the flocculation effect is improved. A known method of making paper using polyethylene oxide (PEO) and polyacrylamide (PAA), which is introduced into the pulp in a pressure box, which increases the retention of the filler and fine G2 fibers. The lack of these methods is large difference in whiteness. Due to the uneven distribution of the filler and fine fiber on the sides of the HWO paper and the different sorption capacity of optical brighteners for pulps and filler, the paper becomes different in shades of color intensity and whiteness. The risk of occurrence of color versatility of existence is greater, the higher the filling of the paper. In addition, the introduction of various amounts of fillers with low whiteness (up to 67%) significantly reduces the whiteness of caitioft paper. Closest to the present invention is a method of making paper, including the introduction into the paper pulp of popiacelamide, an optical brightener and a dye. Moreover, polyacrylamide is introduced into the pulp in the pressure box, and the dp of increasing the retention of filler and paper sizing before adding polyacrylamide is applied to the pulp with a certain amount of sodium aluminate to maintain the pH of the pulp in the range of 6.5-7.5 GZ. In this method, while keeping this order of introducing the components (polyacrylamide to keep the filler in the headbox and the optical bleach or dye to the paper pulp), the paper has different intensity of staining or bleaching on the sides of the sheet. In addition, in this range of pH 6.5-7.5, the effectiveness of polyacrylamide as a retaining agent is not maximal. The purpose of the invention is to improve the optical and color properties of paper while maintaining its physico-mechanical properties. The goal is achieved by the fact that in the paper making method, which includes the preparation of paper pulp, the introduction of an optical brightener or dye, the mass in the presence of anionic or non-ionic flocculant, the optical bleach or dye is mixed with anionic or non-ionic flocculant before the inlet, and the mixture is kept at a temperature of 2O8O and stirring for 0.5-2.5 hours. Anionic substances, for example, polyacrylamide with M. m can be used as flocculating agents. 1, and non-ionic, for example, polyethylene oxide with M.m. 1 Yu - 6 -10, polymers, taken in the amount of 0; OO5-O, 1% by weight of absolutely dry fiber. The consumption of optical bleach or dye is 0, O1-10% by weight of absolutely dry fiber, depending on the required values of whiteness and color intensity. Aqueous solutions of polymers with a concentration of 0, O5-O, 2 g / l and an optical brightener (dye) with a concentration of 5-25 g / l are mixed at a ratio (1: 2) - (1: 1OO) of these components. The resulting mixture is kept under stirring at 20-80 ° C, mainly 50-60 °, for 0.5, 5 hours, preferably 30-60 minutes at a pH of 5.5-8.5. To better dissolve and distribute the components, the temperature of the mixture should not be lowered less; raising temperatures above 80 ° C may lead to decomposition of the compounds used. The preliminary displacement of polymers with bleach or dye increases the affinity of the latter to fillers, as a result of which the molecules of bleaches or dyes, due to electrostatic interaction with the functional groups of flocculant, are more strongly adsorbed and fixed on mineral substances. In addition, the formation of covering systems polyacrylamide - bleach or dye, polyethylene oxide - bleach and dye prevents the penetration of oi molecules of the bleach or dyes deep into the fiber and contributes to their fixing on the surface of the fibrous material. This eliminates losses in optical bleaching or dyeing due to screening scatter. The introduction of an optical bleach or dye into the medium of the polymer just before the paper ejects reduces the reverse desorption of the mothcules of the bleach and dyes into the aqueous phase. All this ultimately leads to an increase and alignment of whiteness and color intensity on the sides of the paper web of the paper being produced while maintaining its physical and mechanical properties. The proposed method can produce paper including fibrous material (cellulose, wood pulp, waste paper, etc.), fillers, rosin glue or synthetic sizing materials and coagulants.) Example 1. By 3 hours (0.03% by weight absolutely dry fiber) 0.2% polyacrylamide solution (PAA molecular weight 2 "1O) is added with stirring for 15 hours (0.15% by weight of absolutely dry fiber) 1% aqueous solution of an optical brightener. The mixture is kept stirring at room temperature () for 30-4 O min., Maintaining the pH 6.5-7.5. The resulting mixture is injected into a naper ocic when the paper pulp is injected including 100% bleached sulfite pulp, 3.0% (by weight of absolutely dry fiber) kaolin with whiteness of 7O%, 1.5% rosin glue, 4.5% aluminum sulphate. The paper web is drained and dried by a conventional paper flow process. In a comparison of the effectiveness of the proposed method, paper under two similar conditions is fabricated in two ways: a mixture of polyacrylamide (PAA) and optical bleaching agents (OOB) are introduced into the pulp; optical bleach is introduced into the pulp, polyacrylamide, in a pressure box before the paper is poured. The consumption of optical bleach is O, 15% by weight of absolutely dry fiber, the consumption of polyacrylimide 0, OZ%. Paper obtained by introducing a mixture of PA A and HBO into pressure chic in front of the start-up of paper pulp is characterized by increased whiteness and the smallest versatility in whiteness. The physico-mechanical properties of the paper do not deteriorate. Example 2. The experiment was carried out analogously to Example 1 with the difference that the mixture of optical bleach and polyacrylamide was incubated for 30 -. 4O Min at 80 ° C. Example 3. To 0.5 part (0.005% by weight of absolutely dry fiber) 0.1% aqueous solution of polyethylene oxide (PEO) (M, m, 5 10) is added while stirring 15 parts (0.15 % of the mass of absolutely dry in blocks) 1% aqueous solution of optical bleach. The mixture is continued to stir at 45-6 O for 30-40 minutes, maintaining the pH 6.5-7.5. The resulting mixture was introduced into the pressure ring when the paper pulp was injected including 1OO% bleached sulfite pulp, ZO% (by weight of absolutely dry fiber) kaolin with whiteness 68 7O%, 1.5% rosin glue and 4.5% sulfur aluminum. The drainage and drying of the paper cloth is carried out according to the usual technological process. To compare the effectiveness of the proposed method, paper under two similar conditions is fabricated in two versions: a mixture of polyethylene oxide (PEO) and an optically bleaching agent (OOB) is introduced into the paper pulp; Optical bleach is introduced into the paper pulp, poly ethylene oxide is introduced into the pressure cylinder before pouring the paper. The costs of PEO and OOB remain equal to 0.005% and 0.15% by weight of absolutely dry fiber. The paper obtained by introducing a mixture of PEO and OOV into the pressure box is characterized by increased whiteness and uniformity of whiteness on the sides of the paper web. Example 4. To 3 parts (0, OZ% by weight of absolutely dry fiber) O, 2% solution of polyacrypamide (Mm 2 "10) are added with stirring 50 hours (O, 5% by weight to absolutely dry fibers) of a 50% aqueous solution of a direct scarlet dye. The mixture was kept under constant stirring for 1 hour. Then, analogously to example 1, the resulting mixture was introduced into the 5PTsIK pressure head while filling the pulp. For comparison, two control variants of paper production were also carried out with the introduction of the ready-mixed mixture of LAA and dyes into the mass and the separate introduction of the dye into the mass, and the PAA into the pressure box. The color intensity of the paper samples obtained is evaluated visually, and in order to reveal the best effect of staining between the variants, the color of the front side of the HbF paper, obtained by introducing dyes into the paper weight, and polyacrylamide into the pressure film, is taken as 1OO%. The results of the analysis of color indicators obtained paper samples are summarized in the table. The paper obtained by introducing a mixture of PAA and dye into the pressure box is distinguished by greater purity and color intensity (by 25-3O%), uniformity of the color of the paper web along the entire length and along the sides. The physico-mechanical properties of the paper do not deteriorate. Example 5. To Oh, 5 parts (0, OO5% by weight of absolutely dry fiber, a 0.1% solution of polyethylene oxide (PEO) (M. 5: 10 °) is added with stirring 50 hours (0, 5% by weight of absolutely dry fiber) of a 5% aqueous solution of a direct scarlet dye. The mixture is kept under constant stirring for 1 hour. Then, as in Example 1, the resulting mixture is introduced into an aperture box before paper is poured. make two control paper options with the introduction of the mixture of PEO and dye into the paper mass and the separate introduction of the dye into the asy, and the PEO into the pressure head chic. The color intensity is also visually assessed with respect to the reference paper sample obtained in the control case of Example 4. The paper obtained by injecting PEO and dyes into the pressure box is characterized by greater intensity, especially color purity and uniformity of color on the sides of the paper. sheet.

Example 6, (comparative). 15 pounds (0.15% by weight of absolutely dry fiber) are added to the paper pulp, including 10O% bleached sulphite pulp, 30% from the weight of absolutely dry kaolin fiber, 1.5% rosin glue, 1.5% sodium aluminate. optical bleach, 3 hours (O, OZ%) of polyacrylamide is injected into the head box when loading paper pulp having a pH of 6.5.

From the data in the table it can be seen that the proposed "papermaking manual provides an opportunity to obtain paper with improved optical and coloristic

85.5 / 85.3

Equivalent:

OOV + PAA in mass

83.2 / 81.9

Sow to mass

PAA in headbox

84.3 / 82.5

2 3 85.9 / 85.8 87.7 / 87.7 equivalent:

HBO + PEO in mass

84.5 / 83.3

Sow to mass

PEO in pressure $ ptsik

86.5 / 85.3

4 13O / 125 are equal:

 85/65

PAA + dye in mass

Dye in mass,

10A / 85 PAA in: pressure chic 125/125

indicators (increase in the degree of whiteness by 3-4%, color intensity by 30-45%) with more uniform indicators of whiteness and color intensity on the sides of the paper sheet while maintaining its physical and mechanical properties.

Using the proposed paper making method allows not only to combine the processes of bleaching or dyeing and flocculation of paper pulp, but also to significantly intensify the papermaking process in general by reducing the time of dyeing and paper bleaching.

18.8 2448

15.1 2515

18.3 2428

18.62440 17.8 2435

14.8 249O

17.5 2420

18.72426 Hue

somewhat cleaner

15.3 25OO Somewhat yellower

18.4

17.5 243О

Comparative:

PEO + paint in the mass 110/90

Dye in mass, PEO in pressure box

6 (prototype)

Claims (3)

1. Fl. DM, M. Paper Properties, 1976, p. 118. 2.Areedter H.F., hAazer A. Papier, 1975, 29, NO 10-A, 32-43. 3. French patent N 127946O, cl. 1) 21 N 1961 (prototype).