UA120670C2 - METHOD OF MANUFACTURING THIN PAPER absorbing VOLOHOTRYVKOHO Sanitary or filter FIBERS appointment with milled cotton pulp, bleached sulfite pulp from coniferous wood and sulphate bleached pulp of eucalyptus wood and aspen - Google Patents

Abstract

The invention relates to the pulp and paper industry and can be used in the production of moisture-resistant paper for sanitary or filter purposes. The method includes grinding cotton pulp fibers to a degree of grinding 36-46 ° SHR (fraction I), fibers of sulfite bleached cellulose from coniferous wood - up to 29-36 ° SHR (fraction II), a mixture of fibers of sulfate bleached cellulose from eucalyptus and aspen wood, for ratio, wt. %, 55 and 45, respectively, to the degree of grinding 17-23 ° SHR (fraction III). The obtained fiber fractions are mixed together before forming a paper web at a ratio in which the content of cotton pulp is 28-32 wt. %, bleached sulfite pulp from softwood - 10-20 wt. %, a mixture of sulfate bleached cellulose from eucalyptus and aspen wood - 52-58 wt. %. As a reinforcing substance to the fibrous suspension is introduced polyvinyl alcohol fiber by mass fraction of 0.22-0.28% of absolutely dry fiber. In the future, the paper web is formed, fastened and dried. The paper is characterized by high mechanical strength, absorbency, looseness and whiteness.

Description

I), a mixture of sulfated bleached cellulose fibers from eucalyptus and aspen wood, according to the ratio, wt. 95, 55 and 45, respectively - to the degree of grinding 17-23 "SHR (PP fraction).

The resulting fractions of fibers are mixed together before forming the paper web in a ratio in which the content of cotton cellulose is 28-32 wt. 95, sulfite bleached cellulose from coniferous wood - 10-20 wt. 95, mixtures of sulfate bleached cellulose from eucalyptus and aspen wood - 52-58 wt. 95. As a strengthening agent, polyvinyl alcohol fiber is introduced into the fibrous suspension at a mass fraction of 0.22-0.28 95 of the completely dry fiber. In the future, the formation of the paper web, its crepe and drying are carried out. The paper is characterized by high mechanical strength, absorbency, fluffiness and whiteness.

The method of making absorbent paper, which includes the processes of grinding cotton pulp, sulfite bleached pulp from coniferous wood, sulfate bleached pulp from deciduous wood, with obtaining a fibrous suspension, introducing a strengthening substance into it, forming a paper web, its creping and drying, which is characterized by that cotton bleached cellulose fibers are ground to a grinding degree of 36-46 "SH (fraction |), fibers of sulfite bleached cellulose from coniferous wood - up to 29-36 "SH (fraction II), and a mixture of fibers is used as sulfate bleached cellulose from deciduous wood sulfate bleached cellulose from eucalyptus wood and sulfate bleached cellulose from aspen wood, by weight ratio. 9o 55 and 45, respectively, ground together to a grinding degree of 17-23 "SHR (fraction II), and the resulting fractions of fibers are mixed before forming the paper web, according to the ratio of components, by weight: cotton cellulose 28-32 sulfite-bleached softwood cellulose 10-20 a mixture of sulfated bleached cellulose from eucalyptus wood and sulfated bleached cellulose from aspen wood 52-58, and polyvinyl alcohol fiber is introduced into the fibrous suspension as a strengthening agent at a mass fraction of 0.22-0.28 95 of completely dry fiber.

The invention belongs to the pulp and paper industry and can be used in the production of moisture-resistant sanitary-hygienic paper or filter paper.

The invention can be most effectively used in the production of paper, for the production of absorbent products for various purposes: napkins, pads, sheets, paper towels, etc., absorbent products in appliances and household appliances.

The application for the invention relates to a method of producing moisture-resistant absorbent paper with increased absorbency and mechanical strength, including in the wet state, namely the preparation of paper pulp, which includes grinding cotton bleached pulp, sulfite bleached pulp from coniferous wood and a mixture of sulfate bleached pulp from wood eucalyptus and sulfate bleached cellulose from aspen wood, obtaining a fibrous suspension, adding a strengthening additive to it, forming a paper web from it in a known way on the grid of a paper machine, its creping and drying.

The task of the work is to achieve increased indicators of absorption (suction) capacity and looseness of paper, the level of mechanical strength, including in a wet state.

The mechanical strength of the paper was evaluated according to indicators of destructive force (in dry and wet conditions), wet strength, absorption capacity was determined according to the indicator

From the average capillary suction in two directions for 10 min., looseness was determined as the inverse value of the paper density.

The disadvantage of absorbent paper for various purposes is that the paper or its products, when slightly wetted and crumpled in the hand, usually crumble and turn into a dense wet mass. That is, products made of such paper have a low level of strength under the slight influence of moisture and low plasticity, which is undesirable for products of this type, intended for wiping and absorbing liquids. As soon as they are saturated with liquid, they become useless (unnecessary), that is, unsuitable for further use.

The invention is based on the task of creating an improved paper canvas with properties similar to fabric or a towel, with high absorbency and low density, which retained integrity and strength under the influence of moisture and behaved like a sponge, due to selection and combination fibers of cotton cellulose, sulfite-bleached cellulose from coniferous wood, sulfate-bleached cellulose from eucalyptus wood and sulfate-bleached cellulose from aspen wood, methods of grinding and introducing a strengthening additive to the resulting paper mass, appropriate preparation of cellulose fibers to form the necessary structure and properties of paper.

Thus, absorbent paper obtained by the proposed method must have the necessary set of properties - be characterized by sufficient absorbent capacity, softness and looseness, as well as appropriate mechanical strength, including in a wet state, to ensure the manufacturability of its processing into products , goods, etc. and conditions of their use and operation. In addition, products made of such paper must have an attractive appearance, that is, be characterized by an appropriate whiteness index.

The strength or physico-mechanical properties of absorbent paper are usually determined by the structure of the paper web, the features of which depend on the capillary-porous structure of the paper. Paper is characterized by anisotropy (unevenness), the distribution, orientation and interaction of all components that create a structure in the volume of a paper sheet, which is related to the peculiarities of the technological process of cellulose fiber preparation, and depends on the type of cellulose, the degree of grinding, the length and thickness of the fibers , the appropriate ratio of the components of the paper mass, the introduction of a binding substance, the conditions for the formation of the paper web, and others.

The invention offers an improved method of producing absorbent moisture-resistant paper with increased indicators of absorbent capacity, fluffiness and mechanical strength, including in a wet state. In particular, the invention relates to a method of obtaining a composition and the ratio of components in it, which, under the appropriate conditions of grinding and preparation of the cellulose fiber of the paper mass, improve the absorbent capacity, looseness and mechanical strength of the paper made from it.

The thickness of the paper is the inverse of the density, which shows how much volume in a cubic meter is occupied by 1 g of paper and is determined as the result of the ratio of its thickness to the mass with an area of 1 m3, in cm3 /g. Fluffness also characterizes the degree of compression of paper, its softness and is an important property of absorbent types of paper for a wide range of applications.

Loose paper has a looser macroporous structure, which is created due to the spaces between the fibers of different types of cellulose and sizes in terms of length and width, which are filled with air and moisture. Loose paper with macropores will intensively absorb liquid components, for example, moisture, and also easily undergo compression. In particular, the invention relates to the composition and the ratio of components in it, which, under the appropriate conditions of grinding and preparation of cellulose fiber (paper pulp), improve the absorption capacity, looseness and mechanical strength of the paper made from it.

To ensure increased mechanical strength and absorbent capacity of paper, softwood pulp and hardwood pulp are usually used, based on the following considerations: long fibers of softwood pulp are flexible, shorten to a lesser extent during grinding, and fibrillate at the same time, which contributes obtaining a closed structure of the paper web. And the use of cellulose fibers from hardwood species in the composition should contribute to obtaining paper with increased absorbency, porosity, and air permeability.

According to the research results, it was also established that the use of cellulose fibers from hardwood species leads to a decrease in the mechanical strength of the material made from them

From paper. This is because hardwood pulp fibers have a smaller cross-section and length than softwood pulp fibers, much less than cotton pulp fibers. At the same time, the fibers of leafy cellulose in the composition with the long-fiber fraction contribute to the increase of such indicators of paper as porosity and air permeability, liquid absorption, looseness, softness and the ability to compress the paper made from them.

It should be noted that in the materials related to the use of leafy cellulose fibers in the composition of paper, they mean cellulose obtained on the basis of aspen wood or a mixture of aspen and birch (GOST 14940 Cellulose sulfate bleached from leafy wood! (aspen). Technical conditions).

Additional research conducted by us showed that such properties as absorption capacity, mechanical strength, looseness (softness) of paper used for the manufacture of, for example, napkins, adhesive plasters, sheets, etc., are affected by the type of cellulose and the method of its preparation before forming the paper web. Of particular importance for ensuring these properties is cotton pulp, which is used for the manufacture of paper with a high set of indicators, which are advanced to absorbent materials, because it is characterized by satisfactory hydrodynamic properties and chemical purity, like cellulose fibers from other annual plants, has long and thin fibers .

Therefore, for the production of absorbent paper for various purposes with the necessary set of consumer properties, we have made an attempt to establish the ratio between the amount of long-fiber fraction from cotton fibers and cellulose from coniferous wood, which is used to create a structural frame, and the amount of short-fiber fraction from cellulose of eucalyptus wood and cellulose from wood aspen, used as a filler or binder, with an optimal mass ratio. 95 long fiber fraction and short fiber fraction.

According to this, the invention relates to a method of obtaining fibrous paper pulp, which includes the selection of fibrous raw materials - cotton pulp ground to a grinding degree of 36-46 "SH, sulfite bleached pulp from coniferous wood, ground to a grinding degree of 29-36 "SH and a mixture of sulfate bleached cellulose from eucalyptus wood and aspen wood, ground to 17-23 "SH, for determining the effective ratio of the composition based on cotton cellulose, sulfite bleached cellulose from coniferous wood and a mixture of sulfate bleached cellulose from eucalyptus wood and sulfate bleached cellulose from aspen wood, wt. 96, respectively 28-32; 10-20; 52-58 and the introduction of a reinforcing substance into the obtained fibrous composition at a mass fraction of 0.22-0.28 95 from completely dry fiber.

On the other hand, the invention relates to the production of thin paper with increased absorbency, mechanical strength, fluffiness and whiteness - important indicators for this type of paper, which includes the following stages: grinding, preparation and production of three types of paper pulp from cotton pulp, sulfite bleached pulp from coniferous wood and mixtures of sulfate bleached cellulose from eucalyptus wood and aspen wood; obtaining a composition of fibrous paper mass based on a mixture of cotton pulp, sulfite bleached pulp from coniferous wood and a mixture of sulfate bleached pulp from eucalyptus wood and aspen wood in their appropriate ratio; introduction of a strengthening additive to the composition of paper pulp; obtaining a fibrous suspension of paper pulp based on a mixture of the resulting composition; forming a paper web from this suspension.

Cotton pulp is used for the production of paper with a high complex of indicators, which are advanced to absorbent materials, because it is characterized by satisfactory hydrodynamic properties and chemical purity, its fibers, like cellulose fibers from other annual plants, have long and thin fibers.

Therefore, in order to increase the strength, fluffiness, softness while maintaining the high ability of paper to absorb the liquid phase, we conducted a study on the selection of the composition of paper pulp based on cellulose fibers from cotton pulp, pulp from coniferous wood and pulp from deciduous wood of eucalyptus and cellulose from of aspen wood, previously ground to the appropriate degree of grinding, using their different dimensions in terms of thickness and length in the appropriate ratio, wt. 95.

Since the fibers of cotton, cellulose from coniferous wood and cellulose from eucalyptus wood and cellulose from aspen wood have different geometric shapes, sizes that change during the grinding process, as well as their ability to swell and fibrillate (combing into small and thin hairs under the influence of water, pressure and grinding head)

Zo - indicators of the degree of grinding of each type of cellulose fibers before preparing the composition of paper pulp were determined.

To ensure increased mechanical strength and absorbency, sulfite-bleached softwood cellulose is also used, based on the following considerations: sulfite cellulose fibers are more flexible and porous, shorten to a lesser extent during grinding, and fibrillate at the same time, which contributes to obtaining a closed paper web.

According to the results of our research, paper based on sulfite-bleached pulp from coniferous wood has lower values of the density index, and, accordingly, higher porosity under the same conditions of pulp pulp fiber grinding. This is confirmed by the increased air permeability of paper based on sulfite-bleached softwood pulp, and naturally, the compressibility of such paper should also increase, i.e., the looseness index of such paper should increase (the value is the inverse of density).

Recently, bleached sulfate cellulose from eucalyptus wood has been widely used.

Eucalyptus pulp is a relatively new fibrous semi-finished product with a-cellulose content of 82 95 and whiteness of 90 95, which, as our previous studies have shown, makes it possible to increase the looseness, softness, porosity and whiteness of paper, providing an attractive appearance of products made of it. to improve the process of its formation.

Eucalyptus fibers are shorter than birch and beech fibers and much thinner than them, the linear density of the fiber is only 60 95 of the indicator of birch fibers and 40 95 of beech fibers, which indicates that 1 eucalyptus pulp contains twice as many fibers as birch fibers and three times more than in beech species. In addition, eucalyptus cellulose fibers are characterized by greater flexibility and plasticity, which is characterized by the ratio of fiber length to its width.

Due to the specific morphological structure and structure, cellulose from eucalyptus wood has a high ability to form a uniform paper sheet and achieve high strength, fluffiness and whiteness.

As the results of the conducted research showed, cellulose from eucalyptus wood is an exceptionally high-quality fibrous semi-finished product with an optimal combination of technical properties for use in the production of highly absorbent types of paper with a content of up to 52-58 95 in the fiber composition of these types of paper.

Aspen pulp has sufficient mechanical strength, but its whiteness is low and does not exceed 80-85,905, and the increased content of the hemicellulose fraction and the less favorable morphological structure of this pulp limit the possibility and content of its use in the composition of absorbent paper. This cellulose quickly loses its absorbent capacity and porosity during the grinding process, limiting the possibility of increasing the strength and fluffiness of the paper.

This can be explained by the fact that the high capacity for hydration (addition of water and swelling) in the process of grinding cellulose from hardwood species, namely aspen wood (brands

OB-1) (c-cellulose content - 71-74 95) leads to a loss of absorbent properties and porosity, with an increase in the degree of grinding, which, in our opinion, is primarily due to its high content of stable pentosans, as well as the presence of degradation products ( oxycellulose), which accumulate as a result of the harsh conditions of pulp bleaching. It also reduces whiteness and its stability under various temperature influences. Therefore, in our opinion, it is important to determine the conditions for grinding cellulose from aspen wood and choose a composition based on it.

The main purpose of grinding the short-fiber fraction of cellulose from eucalyptus wood and cellulose from aspen wood for the production of paper of absorbent types is to increase the plasticity of the fibers for the development and ensuring the strength properties of the fibrous composition. Therefore, the grinding of these types of cellulose was carried out under mild conditions, that is, with minor additives on the surfaces of the grinding set, and the final degree of grinding was chosen depending on the properties and type of cellulose and the ability to preserve the structural, paper-making and absorbent properties of its fibers during grinding and production of low masses of paper with an area of 1 m.

The best indicators of the quality of the obtained paper in terms of the properties of absorbency (capillary suction), fluffiness and softness, and mechanical strength are achieved by grinding cotton pulp up to 36-46 "SR, coniferous pulp up to 29-36 "SR and a mixture of cellulose from eucalyptus wood and cellulose from aspen wood up to 17-23 "SHR.

Under such preparation conditions, cellulose fibers have high structural and paper-forming properties, providing increased paper strength indicators, on the one hand, they do not contribute to a significant increase in the specific surface area of cellulose of cotton, coniferous and eucalyptus wood, contributing to an increase in its looseness (softness) and absorption capacity .

Z Absorbent paper for various purposes has a highly developed porous structure, which leads to a decrease in the forces of connection between the fibers that create its structure. That is, in such paper, the necessary level of the opposite conditions for achieving quality indicators should be ensured: on the one hand, high absorbency and looseness, which are achieved by using a fine mass of unground or slightly ground cellulose fibers and obtaining a highly porous structure, on the other hand, an appropriate level of mechanical strength of the paper, which would not lose its shape and strength when in contact with a wet environment. Achieving the required complex of properties depends on the fibrous components and the technological conditions of their preparation for pouring the paper web.

Under mild grinding conditions, cotton pulp containing 95-98 95 o-cellulose was ground fairly easily, with the formation of thin, long and strong fibrils - fibers, which makes it possible to increase the strength of the produced paper with high absorption capacity.

That is, by combining these positive properties of cotton cellulose fibers with the properties of short eucalyptus cellulose fibers, a synergistic effect occurs, which achieves the best connection between these fibers and their joint action is aimed at improving the structural, physical and consumer properties of paper. And this makes it possible to increase the absorbent capacity of the paper and its mechanical strength, keeping such indicators as whiteness and fluffiness at a high level. Thus, the achievement of positive absorbent paper indicators is ensured by the optimal selection of the structural and metric properties of the fibers of cotton pulp, softwood pulp, eucalyptus wood pulp and aspen wood pulp, their grinding conditions, the degree of grinding and their sizes, which contribute to the formation of the necessary specific surface fibers in the system, which is the composition and fiber matrix of the paper structure.

Eucalyptus sulfate pulp and aspen pulp have a lower strength than cotton pulp and softwood pulp because their fibers are shorter and the strength of the individual fiber in the paper is lower. In addition, the composition of eucalyptus pulp contains a significant number of wide and short thin-walled vessels with a large number of pores and capillaries. That is why the use of this cellulose should contribute to obtaining a paper web with increased capillary absorption capacity, which is an important consumer and operational property of absorbent paper and products made from it.

It is known that materials based on cellulose fibers have insufficient initial (natural), wet strength, therefore, to increase it, binders are introduced into the composition, which contribute to their binding and gluing of fibers together.

In recent decades, considerable attention has been paid to the development of special substances, chemical compounds and materials to give paper or board strength in both dry and wet conditions. Polyvinyl alcohol fiber was obtained as a result of scientific and research work, which is used to increase the strength of paper, including the effects of moisture on it.

Polyvinyl alcohol fiber is a synthetic fiber, a product of alkaline saponification of polyvinyl acetate, characterized by high indicators of relative breaking load, resistance to light and aging, relative elongation, hygroscopicity, resistance to the action of acids, alkalis and organic solvents, preservation of initial strength in a wet state.

A known method of producing crepe paper, which is described in Ukrainian patent 29561 cl. ran 27/00, 021H 17/33 publ. 11/15/2000 Bull. Mo 6, according to which to increase mechanical strength and capillary absorption, a creping composition based on polyamide resin modified with epichlorohydrin, vegetable oil, the product of the interaction of potassium butylate and propylene oxide is used.

However, it should be noted that the proposed method of improving mechanical strength and absorption capacity is complex in terms of its technological implementation, causes difficulties during drying of the paper web (formation of sticky spots on the surface of the drying cylinder) and during creping, which leads to uneven properties along the width paper In addition, this technology leads to an increase in the cost of paper produced using it.

Known patent KO 2432427 C2 "Manufacturing method of multilayer fibrous material" publ. 27.10.2011, bull Me30. The method involves the production of multilayer cardboard, mainly for the packaging industry, using long- and short-fiber cellulose fibers, which are obtained by fractionating the fibrous mass and dividing it into size fractions. The purpose of this invention is to increase the mechanical performance of cardboard and to maximize the use of cellulose from hardwood species of lower

Of the cost than softwood pulp. In this work, short fibrous cellulose from eucalyptus wood, cellulose from birch wood, acacia wood or their mixtures from any two types of wood are used.

Also known is the invention KI 2266139 C2 "Distributing layer with improved transfer of liquid to the retaining layer" on a fibrous material with two or more layers, which has an absorbent layer, which contains a mixture of cross-linked cellulose fibers and non-cross-linked cellulose fibers in the ratio of 85 95 and 15 95, respectively, and intended for liquid absorption. Such a layer has a mass of 1 m: from 90 to 180 g. In one of the variants of the absorbent layer, up to 895 of eucalyptus cellulose, 79% of the mass of southern pine fibers and 85,956 of the mass of cross-linked cellulose fibers are introduced into the composition. Cross-linked cellulose fibers are fibers with chemical crosslinks between the fibers.

In these patents, eucalyptus cellulose fibers are used in layered types of cardboard and materials to improve their mechanical strength and absorbent capacity. However, these materials have a high thickness and mass with an area of 1 me, and the content of eucalyptus cellulose fibers in the adsorbent layer is 8 95.

A well-known filter paper intended for laboratory work and the manufacture of de-ashed filters (author's certificate of the USSR Mo 239793, Д21Н, 18.03.69), which we have taken as a close analogue.

For the production of known paper, a fibrous mixture consisting of 50-60 95 cotton cellulose, 20-25 95 sulfate bleached cellulose from hardwoods and 20-25 95 sulfite cellulose from coniferous wood is used as a paper mass for its formation.

The paper mass for the production of known paper is ground by sequentially grinding first cotton pulp for 10-15 minutes, to which softwood pulp is added and then in 4-6 minutes. before the end of grinding, cellulose from hardwood species is introduced into their mixture. Grinding leads to a grinding degree of 22-44 "SHR.

The formation of a paper web from this mass is carried out according to the usual traditional technology, the mass of a well-known paper with an area of 1 m: is 75 g.

The mentioned paper was chosen by us as an analogue, as it is close in composition of fibrous composition, purpose and technological essence. The use of this technology by analogy contributes to the production of paper with sufficient porosity, but does not allow to fully use the potential of bleached sulfite and bleached sulfate pulp from coniferous and pulp from deciduous wood species, especially for the production of low weight paper with an area of 1 m.

Well-known filter cardboard (Ukrainian invention patent 24205 A dated 30.10.98), which contains a mixture of fibrous semi-finished products in such a ratio, wt. 9o: cellulose from coniferous wood species - 30-40; sulfate cellulose from hardwoods - 20-50, cotton cellulose - 20-40. Grinding of fibrous semi-finished products is carried out on different technological streams: on one, cotton pulp is ground to a grinding degree of 13-16 "ShR; on another - a mixture of pulp from coniferous wood and cellulose from deciduous wood with different ratios of components to a grinding degree of 11-14 "ShR.

Thermoreactive polyamide resin (PAH) in the amount of 0.1-2.5 95 of completely dry fiber is added to the fibrous suspension obtained by mixing ground cotton cellulose fiber and a mixture of coniferous and leafy cellulose fibers in a specified ratio. Forming from this fibrous mass a cardboard canvas with a mass of 1 m? up to 800 g, carried out according to the usual technology.

The mentioned filtering material of increased strength in the wet state was chosen by us as the closest analogue as the closest in terms of purpose, composition of fibrous composition and technological essence.

The use of this cardboard production technology by analogy contributes to its obtaining sufficiently high strength and filtering capacity, but does not allow the production of absorbent paper of a low mass of 1 m: with a uniform structure, high mechanical strength in dry and wet conditions, absorbent capacity and looseness.

And therefore, in order to reduce the negative impact of these shortcomings, we proposed a composition based on cotton cellulose fibers, softwood cellulose and a mixture of sulfate bleached cellulose fibers from eucalyptus wood and sulfate bleached cellulose from aspen wood, their ratio, and also proposed separate grinding of cotton pulp, sulfite bleached pulp from coniferous wood and co-grinding a mixture of sulfate bleached cellulose from eucalyptus wood and sulfate bleached pulp from aspen wood to obtain different fiber lengths, which is important for

From obtaining a macroporous structure and ensuring a high level of absorbency, fluffiness and mechanical strength of paper made from these fibers. Strengthening substances were added to the obtained fibrous composition at the appropriate mass fraction of the completely dry fiber to increase the moisture strength during the action of moisture. Before grinding, the fibers of cotton cellulose were crushed, reducing the length of the fibers to 3-4 mm.

The invention is illustrated by the following examples. Paper samples according to the invention were produced as follows: cotton cellulose fibers were ground to a grinding degree of 36-46 "SH (fraction I), sulfite cellulose fibers from coniferous wood were ground to a grinding degree of 29-36 "SH (fraction II), a mixture of cellulose fibers with of eucalyptus wood and cellulose from aspen wood by mass ratio. 95: 55 and 45, respectively, were ground together to a degree of grinding of 17-23 "SHR (fraction II); the obtained cellulose fiber fractions were mixed with each other in the ratio, wt. 90: 28-32: 10-20: 52-58, respectively. As polyvinyl alcohol fiber (PVA) was added to the fibrous suspension as a reinforcing substance at a mass fraction of 0.22-0.28 95 of the completely dry fiber.

Ground fibers were mixed with each other in water, obtaining a composition in different ratios, wt. 95. Paper samples with an area mass of 1 m² and 32 g were made from the obtained paper mass by a known method (forming, creping to the degree of creping 9 95, drying), which were tested for density and mechanical strength (destructive force in the machine direction in dry and wet conditions) , moisture resistance, capillary absorption on average in two directions during 10 min. and fluffiness. Also, in the process of research, the whiteness index was controlled, which determines the aesthetic properties of finished paper and products made from it.

Example" 1. Paper samples were made from paper pulp, which has a composition of cotton pulp fibers ground to a grinding degree of 46 "SHR (fraction I), sulfite bleached pulp from coniferous wood, ground to a grinding degree of 29 "SHR (fraction II) and a mixture of sulfated cellulose from eucalyptus wood and sulfated cellulose from aspen wood, ground to a grinding degree of 17 "SR (fraction I) according to the ratio, wt. at: 32:10:58 respectively. PVA was added to the fibrous suspension at a mass fraction of 0.22 95 of completely dry fiber.

Example 2 (c;

Paper samples were made from paper pulp with a composition of cotton pulp fibers ground to a grinding degree of 44 "SH (fraction I), sulfite bleached pulp from coniferous wood ground to a grinding degree of 32 "SH (fraction II) and a mixture of sulfate cellulose with of eucalyptus wood and sulfate cellulose from aspen wood, ground to a grinding degree of 19 "SR (fraction I) in the ratio, mass. 90: 30:14:56, respectively. PVA was added to the fibrous suspension at a mass fraction of 0.24 95 of completely dry fibers

Example C

The paper samples were made from paper pulp that has a composition of cotton cellulose fibers ground to a grinding degree of 40 "SH (fraction I), sulfite bleached pulp from coniferous wood ground to a grinding degree of 34 "SH (fraction II) and a mixture of sulfate cellulose with of eucalyptus wood and sulfate cellulose from aspen wood, ground to a grinding degree of 21 "SHR (fraction I!) in the ratio, mass. 90: 28:18:54, respectively. PVA was added to the fibrous suspension at a mass fraction of 0.26 95 of absolute dry fiber.

Example 4

The paper samples were made from paper pulp that has a composition of cotton pulp fibers ground to a grinding degree of 38 "SH (fraction I), sulfite bleached pulp from coniferous wood ground to a grinding degree of 36 "SH (fraction II) and a mixture of sulfate cellulose with eucalyptus wood and sulfate cellulose from aspen wood, ground to a grinding degree of 23 "SR (fraction I!) in the ratio, mass. 9o: 28:20:52, respectively. PVA was added to the fibrous suspension at a mass fraction of 0.28 95 of absolute dry fiber.

Example 5

The paper samples were made from paper pulp that has a composition of cotton cellulose fibers ground to a grinding degree of 36 "SH (fraction I), sulfite bleached pulp from coniferous wood ground to a grinding degree of 36 "SH (fraction II) and a mixture of sulfate cellulose with eucalyptus wood and sulfate cellulose from aspen wood, ground to a grinding degree of 21 "SR (fraction I!) in the ratio, mass. 9o: 32:16:52, respectively. PVA was added to the fibrous suspension at a mass fraction of 0.28 95 of absolute dry fiber.

Example 6 (analog I, patent of Ukraine 24205 A)

Paper was made as follows: cotton pulp was ground separately to a degree

From grinding, 16 "SR (fraction I), and a mixture of sulfite bleached cellulose from coniferous wood and sulfate bleached cellulose from deciduous wood in the ratio, wt. 95, 30 and 40, respectively, were ground together to 14 "SR (fraction I).

Example 7 (analog II, pat. USSR Mo 239793)

The paper pulp for the production of paper samples was obtained as follows: cotton pulp with a mass fraction of 54 96 was ground for 14 minutes, sulfite bleached cellulose from coniferous wood (SFI) was added to the obtained fiber with a mass fraction of 23 95 and ground together to a grinding degree of 23 "SHR . To the resulting mixture, sulfated bleached cellulose from hardwood species (CLD) was added to the mass fraction of 23 95 and ground to a grinding degree of 43 "SHR. A strengthening substance - polyamide resin (PAH) was added to the obtained fibrous suspension at a mass fraction of 0.3 95 of completely dry fiber. Paper samples with a weight of 1 m2-32 g were produced from the obtained paper mass in a known manner, similarly and according to the application.

The resulting fractions I and II were mixed according to the ratio of components, mass 90: cotton cellulose - 30, cellulose from sulfite-bleached coniferous wood - 30 and cellulose from hardwood species (CLD) - 40, respectively. Polyamide resin (PAH) was added to the resulting composition of paper pulp at a mass fraction of 0.3 95 of completely dry fiber. Paper samples with a weight of 32 g/me were produced from the obtained paper pulp in a known manner, similarly and according to the application. The obtained samples according to the invention (1-5) and analogues (6 and 7) were tested under the same conditions, and the test results are shown in the table.

The offered paper is characterized by sufficiently high strength in both dry and wet conditions, with a reduced mass of 1 m? paper, which is an undoubted advantage in the production of materials and products with increased absorption capacity, especially multilayer ones. The reduced mass of 1 square meter of paper makes it possible to manufacture products and materials with several layers and precisely due to this, to increase their softness and strength properties under various influences, conditions of use with a significant increase in absorption capacity.

A high level of indicators of mechanical strength, absorption capacity, looseness, which is ensured, in our opinion, by the optimal selection of the fiber composition from the cellulose fibers of cotton cellulose, sulfite bleached cellulose from coniferous wood and a mixture of sulfate bleached cellulose from eucalyptus wood and cellulose from aspen wood, their bo dimensions in terms of length and thickness, which contributes to the formation of a macroporous structure,

paper made from them. The resulting macroporous structure, in turn, ensures the achievement of high fluffiness, which is also an indirect characteristic of air permeability and absorbency indicators, and the presence of long fibers of cotton cellulose in the composition makes it possible to increase and ensure the mechanical strength of the paper at a sufficiently high level. The introduction of a small amount of polyvinyl alcohol fiber into the composition of the paper helps to increase the strength of the paper in contact with water (moisture), which expands the scope and increases the efficiency of its use of such paper and products made from it.

Table;

Fibrous COMPOSITION Destructive

Mixture Bulk Capillary

Variant of Sulfite cellulose pobivinl- Thin- Wet-moist: (example) Cotton bipen " bleached with alcohol 1 ness, For strength, for Fluffness, Whiteness. by two cm /g ate a target - from conifers 3 from a.s. |z 71 | 321 10 | 58 | 022 |z2l1|0243| 59 |040| 68 | 36 | 416 | 86 72 | 30 | 14 | 56 | 024 /920| 0243 63 |047| 74 | 39 | 415 | 86 3 | 281 18 | 54 | 026 | z319 | 0245 | 68 | 063 | 94 | 39 | 415 | 86 5 | 32 | 16 | 52 | 028 /320 | 0244 80 | 076 | 95 | 44 | 413 | 87 iseksyu| sho | o ez|ozyu| ve |v you | z | zyu| e eat| | z ish liu |eeC|oto| vv o», vv | z | za | in

That is, the joint use under the appropriate conditions and ratios in the composition of the paper pulp of fibers of cotton cellulose and cellulose from coniferous wood occurs, their positive effect on the creation of such a structure of the paper web, which provides a synergistic effect on increasing indicators of both mechanical strength and absorbent capacity and looseness of paper.

It should also be noted that the paper samples according to the invention are characterized by a sufficiently high level of whiteness index, which determines the high level of aesthetic properties and attractive appearance of paper and products made from it.

Paper made according to analogues, using a mixture of bleached cotton pulp fibers, sulfite pulp from coniferous wood and traditional pulp from hardwood species (birch, beech, aspen) also provide a sufficiently high level of mechanical strength of the paper in the wet state. However, such paper is harder, less plastic, which is evidenced by the reduced level of looseness (softness) and absorbent capacity, which is important for absorbent types of paper and products made from them and does not provide, as our research has shown, a significant increase in absorbent capacity ability while maintaining the required level of mechanical strength of paper with a reduced weight of 1 m.

With this technology, there are also difficulties in ensuring the uniformity of low-weight paper of 1 m2-32 g. This can be explained by the fact that according to the analog technology, no

How is the necessary degree of shortening and fibrillation of the fibers of cotton cellulose and softwood pulp achieved, which, in turn, does not allow the formation of a paper web from these fibers of a uniform structure, density, thickness and mass of 1 m? and ensure the necessary level of its consumer properties.

The best results of the researched characteristics of the paper according to the application are achieved with a relatively low content of cotton cellulose fibers and coniferous wood pulp, which have a higher value compared to other cellulose fibers in the composition, and accordingly, this will contribute to reducing the cost of absorbent paper with a high set of properties such as capillary absorption, friability and mechanical strength.

Paper and paper products can be used without breaking down when wetting and crumpling when wet or to remove residual moisture, for example, or dirt from various surfaces.

Claims (1)

FORMULA OF THE INVENTION The method of making absorbent paper, which includes the processes of grinding cotton pulp, sulfite bleached pulp from coniferous wood, sulfate bleached pulp from hardwood wood, with obtaining a fibrous suspension, introducing a strengthening substance into it, forming a paper web, its creping and drying, which differs by the fact that cotton cellulose fibers are ground to a grinding degree of 36-46 "SH (fraction I), sulfite bleached cellulose fibers from coniferous wood - up to 29-36 "SH (fraction II), as sulfate bleached cellulose from deciduous wood, a mixture of sulfate fibers is used bleached cellulose from eucalyptus wood and sulfate bleached cellulose from aspen wood, by ratio, wt. 90, 55 and 45, respectively, ground together to a grinding degree of 17-23 "SR (fraction II), and the obtained fiber fractions are mixed before forming the paper web, according to the ratio of components, by weight: cotton cellulose 28-32 sulphite bleached cellulose with coniferous wood 10-20, a mixture of sulfated bleached cellulose from eucalyptus wood and sulfated bleached cellulose from aspen wood 52-58, and as a reinforcing substance, polyvinyl alcohol fiber is introduced into the fibrous suspension at a mass fraction of 0.22-0.28 95 from completely dry fiber. 000 KomputernaverstkaL.Tsikhanovska.d (00000000 Ministry of Economic Development, Trade and Agriculture of Ukraine, St. M. Hrushevskyi, 12/2, Kyiv, 01008, Ukraine SE "Ukrainian Institute of Intellectual Property", str. Glazunova, 1, Kyiv - 42, 01601