RU2365326C2 - Pressed product in wet condition in form of toilet paper and towels with increased coefficient of elongation in cross-section direction and low strength ratio value, made with application of creping process on tissue at high solid substance content - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: absorbing cloth from a cellulose fiber contains an admixture of hard wood and soft wood fibers located in the form of mesh structure, including: the set of columnar areas fibers conglomeration with relatively high local density, aggregated by means of set of the connecting areas with lower local density, where orientation of fibers is inclined along a longitudinal direction between the columnar areas interconnected in a such way, where the cloth possesses coefficient of elongation in a cross-section direction, which is at least in 2.75 times higher than relative strength at cloth stretching in a dry condition. The above-stated material is obtained as follows. A water cellulose composition from hard wood fibers is prepared. The composition is moved on a forming tissue in the form of a stream which is let out from a pressure head box with a flow rate. The composition is dehydrated and compacted for manufacturing of a paper for formation of the fibrous layer possessing chaotic distribution of a fiber for paper manufacturing. Packing of the dehydrated fibrous layer possessing chaotic distribution of a fiber on the transporting transferring surface moving with the first rate. Creping of a fibrous layer from the transferring surface on a tape at dryness from 30% to 60% with use of the pattern creping tape. The creping stage is carried out under pressure in a contact zone of the creping tape confined between the transferring surface and the creping tape. Thus the tape is moved with the second speed, lower than speed of the transferring surface. Tape drawing, parametres of a contact zone, speed difference and dryness of the fibrous layer are chosen in such way to crepe the fibrous layer at its removal from the transferring surface and to redistribute on the creping tape with formation of a fibrous layer with mesh structure. Drying of the fibrous layer is performed after. The process is regulated so that coefficient of elongation in a cross-section direction is, at least, approximately in 2.75 times higher than relative strength at stretching of the fibrous layer in a dry condition. Such method allows obtaining a cellulose fibrous layer for products made from thin paper, and also products in the form of towels.

EFFECT: improvement of ready product quality and power consumption decrease.

33 cl, 10 dwg, 22 tbl

Description

Technical field

This application is directed, in part, to a method in which the fibrous layer is dehydrated with a seal, creped into a creping fabric and dried, the process being controlled in such a way as to produce products with high elongation in the transverse direction and low tensile strength ratios in longitudinal and transverse directions.

BACKGROUND OF THE INVENTION

Methods for making tissue paper to produce toilet paper, towels, and the like. they are well known, and they include various processes, for example, drying using a Yankee dryer, drying by air suction, creping on fabrics, creping in a dry state, creping in a wet state, etc. Conventional wet pressing methods have certain advantages over conventional drying methods by sucking air, including: (1) lower energy costs associated with mechanical removal of water compared to evaporation during drying with hot air; (2) higher productivity, which is easier to achieve when using processes involving wet pressing to form the fibrous layer. On the other hand, drying by means of air suction was accepted, and new investments were made for its development, especially for the manufacture of soft, bulk, thin paper of high quality and an assortment of products in the form of towels.

Crepe fabric was used in papermaking processes, including mechanical dewatering or dehydration with compaction of the fiber layer as a means of influencing product properties (see US Pat. Nos. 4,689,119 and 4,551,199, registered to Weldon; 4,849,054 and 4,834,838, registered to Klowak ; No. 6287426, registered in the name of Edwards et al.). The introduction of creping processes on the fabric was hindered by the difficulty of transferring the fibrous layer with high or medium dryness to the dryer. You should also pay attention to US patent No. 6350349, registered in the name of Hermans and others, which disclosed a method of transferring in the wet state of the fibrous layer from a rotating transmission surface to the fabric. Other patents related in a more general form to fabric creping include US Pat. Nos. 4,834,838, 4,482,429, 4,445,638, and 4,440,597, registered in the name of Wells et al.

In papermaking processes, fabric molding was also used as a means to provide texture and bulk. In this regard, U.S. Patent No. 6610173, registered in the name of Lindsey et al., Proposes a method for imprinting a fibrous layer during wet pressing, resulting in asymmetric protrusions corresponding to the deflecting tubes of the deflecting member. U.S. Patent No. 6610173 teaches that transfer with a difference in speed during pressing serves to improve the molding and imprinting of the fibrous layer by means of a deflecting member. It is described that the fabricated thin fibrous layers possessed complexes of physical and geometric properties, for example, a densified patterned mesh structure and a repeating pattern of protrusions having asymmetric structures. For the wet forming of a fibrous layer using textured fabrics, the following US patents should also be read: No. 6017417 and No. 5672248, registered in the name of Wendt et al .; No. 5508818 and No. 5510002, registered in the name of Hermans and others, and No. 4637859, registered in the name of Trokhan. Regarding the use of fabrics to texture a generally dry web, see US Pat. No. 6,585,855, registered in the name of Drew et al. And US Publication No. US 2003/00064.

Crepe products obtained by drying by air suction are described in the following patents: US Pat. No. 3,994,771, registered in the name of Morgan, Jr. and etc.; US patent No. 4102737 registered in the name of Morton; US patent No. 4529480 registered in the name of Trokhan. The methods described in these patents contain, in a very general form, the processes of forming the fiber layer on a perforated support, pre-drying the fiber layer, laying the fiber layer on the working body of the Yankee dryer, determining the contact zone, partly by pressing the fabric, and creping product at the outlet of the Yankee dryer. A relatively permeable fibrous layer is usually required, which complicates the use of the secondary composition at levels that would be desirable. Transfer to a Yankee dryer is usually carried out with a dry fiber layer from about 60% to about 70%; although in some cases the transfer is carried out at much higher values of dryness, sometimes even approaching a value called air-dry.

As mentioned above, products obtained using drying by air suction often have increased bulk and softness; however, with thermal dehydration using hot air, there is a tendency to increase energy intensity. Wet pressing operations in which the fibrous layers are mechanically dehydrated are preferable in terms of energy consumption and more easily applicable to compositions containing a secondary fiber, which tends to form a fibrous layer of lower permeability than when using the primary fiber. Many improvements have been proposed to increase the bulk and absorption capacity of densified dehydrated products, which are usually dehydrated, in part, with paper cloth.

Despite the achievements in this field, when using known methods of pressing in the wet state, fibrous layers with increased absorption capacity and preferred physical properties, especially with increased relative elongation in the transverse direction with relatively small values of the ratio of tensile strength in the longitudinal and transverse directions, were not obtained. which is desirable when using high-quality thin paper and towels.

According to the present invention, the absorption capacity, bulk and elongation of the fibrous layer obtained by wet pressing can be improved to a wide extent by creping the fibrous layer on the wet fabric and reshaping the fibers on the creping fabric, while maintaining an increased speed, the efficiency of heat treatment and the possibility of using secondary fiber in the composition, as is usually practiced in wet pressing processes.

SUMMARY OF THE INVENTION

Thus, in a first aspect of the invention, there is provided an absorbent cellulosic fiber web comprising a mixture of hardwood (TD) and softwood (MD) fibers arranged in a mesh structure including: (i) a plurality of columnar fiber clusters with a relatively large local density, interconnected by (ii) multiple connecting regions with lower local density. The orientation of the fibers in the connecting regions is inclined along the direction between the columnar regions interconnected in this way. The relative density, the degree of columnarity, the ratio of hardwood to softwood, fiber length distribution, fiber orientation and mesh structure are controlled so that the web has a relative elongation in the transverse direction, which is at least about 2.75 times greater relative tensile strength of the web in the dry state. In one preferred embodiment, the web has a porosity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 5%, and a ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction, constituting less than about 1.75. In another preferred embodiment, the ratio of the tensile strength in the longitudinal direction to the tensile strength in the transverse direction is less than about 1.5. In another preferred embodiment, the web has an absorption capacity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 10%, and a ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction, less than about 2.5. In another preferred embodiment, the web has an absorption capacity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 15%, and a ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction less than about 3.5. In an even more preferred embodiment, the web shows a relative elongation in the transverse direction of at least about 20%, and a ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction of less than about 5, which seems to be achievable according to the present invention.

As can be understood from the analysis of the data below, elongation in the transverse direction, which would be at least about 3, 3.25 or 3.5 times greater than the relative tensile strength in the dry state, can be easily achieved according to the present invention.

In general, a relative elongation in the transverse direction of at least about 4% and a relative tensile strength in the range of about 0.4 to about 4.0 are typical of a product according to the invention. Preferably, the product has a transverse elongation of at least about 5% or 6%. In some cases, an elongation in the transverse direction of at least about 8% or at least about 10% is preferred.

Products according to the invention typically have a porosity of at least about 5-6 g / g. A porosity of at least about 7 g / g, 8 g / g, 9 g / g, or 10 g / g is also typical.

The web according to the invention may consist predominantly (more than 50%) of hardwood or softwood fiber. Typically, the web contains a mixture of these two types of fibers.

In another aspect of the invention, a method for manufacturing a cellulosic fibrous layer for producing toilet paper, towels, comprising the steps of: (a) preparing an aqueous cellulosic composition for making paper; (b) feeding the paper composition to the forming fabric as a stream discharged from the headbox at a flow rate; (c) compacted dewatering of a paper making composition for forming an initial fibrous layer having an apparent random distribution of fiber; (d) laying the dehydrated fibrous layer having an apparent random distribution of the fiber on a conveying transmission surface moving at a first speed; (e) creping on the tape of the fibrous layer from the transfer surface with a dryness of from about 30% to about 60% using a patterned creping tape; moreover, the creping stage is performed under pressure in the contact zone of the creping tape, limited between the transmitting surface of the creping tape, where the tape is moved at a second speed less than the speed of the transmitting surface. The tape pattern, contact zone parameters, speed difference and dryness of the fiber layer are selected so that the fiber layer is creped when removed from the transmitting surface and redistributed on the creping tape to form a fiber layer with a mesh structure containing many interconnected regions with different local densities, including at least (i) a plurality of fiber clusters with relatively high local density interconnected by (ii) a plurality of connective regions less local density. The fibrous layer is then dried. It is shown that the ratio of the fiber content of hardwood and softwood, the distribution of fiber length, the total degree of creping, the flow rate, the stage of drying and creping on the tape is regulated, and the pattern of the creping tape is selected so that the fibrous layer differs in that it has a relative elongation in the transverse direction, which is at least about 2.75 times greater than the relative tensile strength of the fibrous layer in the dry state. These parameters are also chosen so that the properties indicated above when describing the products according to the invention are achieved in various embodiments of the invention.

The method according to the invention can be used with the predominant use of hardwood fibers for the manufacture of a base fabric for the production of thin paper, or the method according to the invention can be used with a composition consisting primarily of soft wood fibers, if desired, for the manufacture of towels. One skilled in the art will appreciate that other additives may be selected, if desired.

It has been found according to the present invention that fibrous layers containing local density fluctuations are preferably calendered between steel calender shafts when calendering is desired.

The fibrous layer creped on the tape according to the invention is usually characterized in that the fibers of the clusters are inclined in the transverse direction, as can be seen when considering the attached photographs.

In general, the process is performed on a creping fabric, reaching a creping degree of from about 10% to about 100%. Preferred embodiments include those in which the process was performed on a creping fabric, achieving a creping degree of at least about 40%, 60%, 80%, or 100%, or more. The method according to the invention can be performed on creping fabric, reaching a degree of creping 125% or more.

The method according to the present invention is very tolerant to the composition, and can be carried out using large amounts of secondary fiber, if desired.

Additional features and advantages of the present invention will become more apparent upon reading the following sections of the description.

Brief Description of the Drawings

The invention is described in detail below with reference to the drawings, which depict:

figure 1 is a photograph (120-fold increase) of the cross section in the longitudinal direction of the accumulation of fibers in the fabric, creped on the fabric;

figure 2 is a diagram of the relationship of the tensile strength in the longitudinal direction to the tensile strength in the transverse direction in the dry state on the difference between the flow rates and the mesh conveyor, ft. / min;

figure 3 is a photograph (10-fold increase) crepe on the fabric of the fibrous layer from the side of the creping fabric;

figure 4 is a flow chart of a paper machine that can be used to manufacture products and implement the method according to the present invention;

5 and 6 are diagrams of the dependence of the elongation in the transverse direction on the ratio of the tensile strength in the longitudinal direction to the tensile strength in the transverse direction of a fabric with a density of 13 pounds, made using various fabrics and with different degrees of creping;

7-9 are diagrams of the dependence of the elongation in the transverse direction on the ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction of webs with a density of 24 pounds according to the invention;

figure 10 is a diagram of the dependence of the decrease in thickness on pressure during calendering using various combinations of steel and rubberized calender shafts.

Detailed description

The following is a detailed description of the invention with reference to some embodiments and a number of examples. The purpose of this consideration is only to illustrate the invention. The specialist in this field is quite obvious possible modifications of specific examples within the essence and scope of the present invention presented in the attached claims.

The terminology used in the present description is used in its usual meaning, and the following are approximate definitions.

The absorption capacity (SAT) (AC) of articles according to the invention is determined using a simple absorption capacity meter. A simple device for measuring adsorption capacity is particularly suitable for determining the hydrophilicity and absorption capacity of a sample of tissue paper, napkins or towels. In these tests, a sample of thin paper, napkins or towels with a diameter of 2.0 inches is placed between the upper flat plastic cover and the lower corrugated object plate. A mug of tissue paper, tissue or towel is held in place by its edges at a width of 1/8 inch. The sample is not compressed by the holder. Deionized water is poured onto a sample in the central region of the lower plate at a temperature of 73 ° F (22.78 ° C) through a 1 mm diameter tube. This water is under hydrostatic pressure minus 5 mm. The flow is initiated by a pulse supplied at the beginning of measurements using the mechanism of the device. Water is thus absorbed by a sample of tissue paper, tissue paper or towels from this central entry point in radial directions from the center to the periphery due to capillarity. When the rate of water absorption becomes less than 0.005 g of water in 5 s, the tests are terminated. The amount of water poured from the tank and absorbed by the sample is determined by weighing and recorded in grams of water per square meter of sample, unless otherwise indicated. Practically used a gravimetric device to determine the absorption capacity of the company M / K Systems Inc. This is a commercially available appliance from M / K Systems Inc. (12 Garden Street, Danvers, Mass., 01923, United States). The absorption capacity (water) (AC) (WAC), also abbreviated as SAT, is actually measured with this instrument. The absorption capacity (water) (AC) (WAC) is determined by the point at which the line in the diagram of the change in mass with time has a “zero” slope, i.e. the sample ceases to absorb water. The termination criterion is expressed in the maximum change in the mass of absorbed water over a fixed period of time. This is a basic estimate of the zero slope of the line in the mass change over time diagram. The program uses a change interval of 0.005 g for 5 s as a criterion for terminating the test, unless the condition “Slow SAT” (slow absorption) is specified, according to which the criterion for terminating the test is 1 mg for 20 s.

When in this description and the claims it is stated that there is an obvious chaotic distribution of the orientation of the fibers in the original fibrous layer (or use similar terminology), they mean the distribution of the orientation of the fibers, which is obtained with the known molding technologies used for filling the composition onto the forming fabric. During microscopic studies, it is found that the arrangement of the fibers presents a picture of a chaotic orientation, even if (depending on the ratio of the flow rates of the composition and the conveyor tissue) there can be a significant orientation bias towards the longitudinal direction, resulting in tensile strength of the fibrous layer in the longitudinal direction exceeds tensile strength in the transverse direction.

Under the term "density" (BWT), (bwt), etc. (unless otherwise specified) understand the mass of the foot of paintings of 3000 square meters. foot. (278.7 m ² ). The term "dryness" means the percentage of solids in the initial fibrous layer, for example, calculated on the basis of the content of absolutely dry matter. The term "air dryness" means the content of residual moisture, usually up to about 10% moisture for pulp and up to about 6% for paper. It is believed that the initial fibrous layer containing 50% water and 50% absolutely dry pulp has a dryness of 50%.

Under the term “cellulosic”, “cellulosic web”, and the like. understand any product, including fiber for making paper, containing cellulose as a main component. By the words “papermaking fiber” is meant primary pulp or reusable (secondary) cellulosic fibers or fiber mixtures containing cellulosic fibers. Fibers suitable for making webs according to the present invention include: non-wood fibers, for example, cotton fiber or derivatives of cotton fiber, manila hemp, kenaf, sabai grass, flax, esparto grass, straw, jute, hemp, bagasse, milkweed fluff, fiber from pineapple leaves; wood fibers, for example, obtained from hard and softwoods, including fibers from softwoods, for example, kraft pulp fibers of northern and southern softwoods; hardwood fibers, for example, eucalyptus, maple, birch, poplar (aspen), etc. Fiber for making paper can be obtained from sources of these fibers by any of the methods, including chemical methods for producing pulp known to specialists in this field, including: sulfate, sulfite, polysulfide, soda pulp, etc. The pulp can be bleached, if desired, by chemical means, including the use of chlorine, chlorine dioxide, oxygen, etc. The products of the present invention may contain a mixture of conventional fibers (obtained from primary cellulose or from recycled sources) and very coarse, lignin-rich tubular fibers, for example, bleached chemical thermo-mechanical pulp (OXTMBM) (BCTMP - latin. Alpha). The term "composition" and similar terms mean aqueous compositions containing fiber for making paper, polymers, imparting strength in the wet state, baking powder, etc. for the manufacture of products.

The words “densified dewatering” of a fiber layer or composition as used herein refers to mechanical dewatering by wet pressing on a drying cloth, for example, in some embodiments, by using mechanical pressing that is applied continuously to the surface of the fiber layer, for example, in the contact area between the press roll and the shoe of the press, where the fibrous layer is in contact with paper cloth. The term “densified dewatering” is used to distinguish between processes in which the initial dehydration of the fiber layer is carried out mainly by heat, such as, for example, US Pat. No. 4,529,480 to Trokhan and US Pat. No. 5,605,551 to Farrington. and others mentioned above. The dehydration with densification of the fiber layer, therefore, relates, for example, to the removal of water from the original fiber layer having a dryness of less than 30% or near this value by pressing it, and / or to increase the dryness of the fiber layer by about 15% or more by his pressing.

The words “from the side of the fabric” and similar terms mean the side of the fibrous layer in contact with the creping and drying fabric. The words “from the side of the drying machine” and similar terms mean the side of the fibrous layer opposite to the side facing the fabric.

The abbreviation fpm means ft./min; while the term "dryness" means the content (wt.%) of the fiber in the fibrous layer.

The abbreviation MD refers to the longitudinal direction (PR) (machine direction), the abbreviation CD refers to the transverse direction (PN) (machine direction).

The parameters of the contact zone include (without limitation): pressure in the contact zone, length of the contact zone, hardness of the support shaft, angle at the point of tissue approach, angle at the point of tissue separation, uniformity and difference of surface speeds in the contact zone.

By the length of the contact zone is understood the distance at which the surfaces entering this zone are in contact.

The term “on line” and similar terms mean the stage of the process, carried out without removing the fibrous layer from the paper machine on which this fibrous layer is made. The fibrous layer is stretched or calendared "on line" (on the line), if it is pulled or calendered, not dividing into parts before winding.

By the words “conveying transmission surface” is meant the surface from which the fibrous layer is transferred with creping to the creping fabric. A “conveying transfer surface” may be the surface of a rotatable drum, as described below, or the surface of a continuous smooth movable fabric or other movable fabric, which may have a textured surface, etc. A transporting transfer surface is required to maintain the fibrous layer, and with its help creping is carried out at a high solids content, as described below.

The thickness and / or bulk referred to in this description may represent the thickness of 1, 4 or 8 paintings, the sheets are laid on top of each other, and the thickness of the floor is measured in the region of its central part. It is preferred that the test samples be conditioned in an atmosphere where the temperature is 23 ° C ± 1.0 ° C (73.4 ° F ± 1.8 ° F) and the relative humidity is 50% for at least about 2 hours, after which their thickness is determined using a Model 89-II-JR device or a Prowing electronic thickness gauge from Thwing-Albert, with 2-inch (50.8 mm) probes, at a constant load of 539 ± 10 g and at a lowering speed <moving probe> 0.231 in / s. To test the finished product, each sheet to be tested must contain the same number of layers as the product on sale. For testing, eight canvases are generally selected and lay on top of each other. For testing napkins they are folded before laying. For testing the base web, it is wound from a roll, each web to be tested must contain the same number of layers as that removed from the run. To test the base web from the roll of a paper machine, use layers one at a time. The canvases are laid on top of each other, combining their longitudinal directions. When testing custom-embossed or printed products, try to exclude measurements in these areas, if at all possible. Bulkness can also be expressed in units corresponding to the volume / mass ratio obtained by dividing the thickness value by the density value.

Indicators: tensile strength in the dry state (in the longitudinal direction and in the transverse direction), elongation, the ratio of these indicators, the tensile modulus, the load-elongation curve, is determined using a standard Instron tensile testing machine or other suitable device to determine the relative elongation under tension, which can be performed in various configurations, and usually as samples use strips of thin paper or towels with a width of 3 or 1 inch, air-conditioned x at a relative humidity of 50% and a temperature of 23 ° C (73.4 ° F); tensile tests are performed at a rolling clamp speed of 2 inches / min.

Relative tensile strength is simply understood as the ratio of the values determined above by the methods described. Relative tensile strength is understood to mean the ratio of the tensile strength of the web in the dry state in the longitudinal and transverse directions, unless otherwise indicated. Tensile strength is understood to mean the properties of the web in a dry state, unless otherwise indicated. Tensile strength is sometimes called simply tensile. Tensile strength, elongation, etc. shown below in the present description, unless otherwise indicated.

The term “creping on fabric” refers to the difference between the speeds of the creping fabric and the forming mesh conveyor, and is usually calculated as the ratio of the speed of the fibrous layer immediately before creping to the speed of the fibrous layer immediately after creping, since the forming mesh conveyor and the transfer surface are usually, but not necessarily move with the same speed.

The creping ratio on the fabric is equal to the speed of the transfer cylinder divided by the speed of the creping fabric.

The degree of creping on the fabric can also be expressed as a percentage:

The degree of creping on the fabric (%) = (The ratio of creping on the fabric - 1) x 100

Creping along the entire line (sometimes called total creping), creping on the coast, etc. calculated in the same way as shown below.

The abbreviations PLI or pli stand for lbf / linear inch (psi).

Under the word "predominantly" understand: more than about 50%, usually - wt.%; when referring to fiber, the calculations are based on the calculation of absolutely dry matter.

Pusey and Jones hardness (P + J) (determined by the indentation method), sometimes denoted by (P + J), is determined by ASTM D 531 and expressed by the indentation number (using standard samples and conditions) (ASTM - American Society for Testing Materials) .

By "speed difference" is understood the difference in linear velocities.

Porosity and / or relative porosity, as described below, is determined by impregnating the web with non-polar POROFIL ^® fluid and measuring the amount of absorbed fluid. The volume of liquid absorbed is equivalent to the pore volume in the web structure. Relative mass increase (PWI) (%) is expressed by the mass (g) of fluid absorbed by 1 gram of fiber of the web structure times 100, as described below. More specifically, for each single layer sample of the web to be tested, 8 webs are selected and a 1 x 1 inch square is cut out (1 inch in the longitudinal direction and 1 inch in the transverse direction). For samples of multilayer products, each layer is tested as a separate object. Many samples should be separated in separate unit layers, and 8 sheets should be cut from each position (layer) used for testing. The dry mass of each test sample tested is determined by weighing to the nearest 0.0001 g (to the nearest value) and recorded. Place the test sample in a cup containing POROFIL ^® fluid having a specific gravity of 1.875 g / cu. cm supplied by Coulter Electronics Ltd. (Northwell Drive, Luton, Beds, England) (part No. 9902458.). After 10 seconds, capture a test sample with tweezers at one corner, at the very edge (1-2 mm), and remove it from the liquid. Hold the test sample with this angle upward for 30 s and allow excess liquid to drain. Lightly apply a test sample (less than half a second) with the bottom angle to filter No. 4 (Whatman Lt. filter, Maidstone, England) to remove any excess liquid (to the last drop). Immediately weigh the test sample for 10 s and record the mass with an accuracy of 0.0001 g (to the nearest value). The relative weight gain (PWI) (%) of each test sample, expressed as the mass (g) of POROFIL ^® fluid absorbed in 1 gram of fiber, is calculated as follows:

PWI = [(W ₂ -W ₁ ) / W ₁ ] x 100%,

Where

W ₁ = dry test sample weight, g;

W ₂ = mass of the wet test sample, g

The relative weight increase (PWI) (%) of all eight separate test samples is determined as described above, and the average value calculated from the eight test samples is taken as the relative weight increase (PWI) of this sample.

Relative porosity is calculated by dividing the relative mass increase (PWI) by 1.9 (liquid density) to express the ratio as a percentage, since the porosity (g / g) is simply a relative mass increase; those. relative weight gain (PWI) divided by 100.

According to the present invention, an absorbent fiber layer is formed by dispersing a paper making fiber in an aqueous composition (slurry) and spraying the aqueous composition onto a forming paper conveyor of a paper machine, typically in the form of a stream discharged from a headbox. Any suitable molding technique may be used. For example, an extensive, but not exhaustive list, in addition to the Fourdrinier molding machines, includes: a sickle-shaped forming part, a forming part with two mesh conveyors with a C-shaped coverage; forming part with two mesh conveyors with S-shaped coverage; forming part with suction chest shaft. As the forming fabric, any suitable perforated structure may be used, including single-layer fabrics, two-layer fabrics, three-layer fabrics, photopolymer fabrics, and the like. A non-exhaustive list of analogs of forming fabrics includes the solutions described in US Pat. 4564052; 4592395; 4611639; 4640741; 4709732; 4759391; 4759976; 4942077; 4967085; 4998568; which are incorporated into this application in full by reference. One forming fabric particularly suitable for carrying out the present invention is Model 2164 forming fabric manufactured by Voith Fabrics Corp. (Shreveport, pc. Louisiana, USA).

The formation of the fibrous layer of the foamed aqueous composition on a forming mesh conveyor or forming fabric can be used to control the permeability or porosity of the fabric when creping it on the fabric. Methods for forming a fibrous layer from a foam composition are disclosed in US Pat. No. 4,543,156 and Canadian Patent No. 2,053,505, the disclosure of which is incorporated herein by reference. A foamed fiber composition is prepared from an aqueous suspension of fiber mixed with a foamed liquid carrier immediately before being introduced into the headbox. The concentration of fiber in the suspension of pulp fed into the system is in the range of from about 0.5 wt.% To about 7.0 wt.%, Preferably in the range of from about 2.5 wt.% To about 4.5 wt. % The pulp suspension is added to a foamed liquid including water, air and a surfactant containing 50-80 vol.% Air, whereby a foamed fibrous composition is formed with a fiber concentration in the range from about 0.1 wt.% To about 3, 0 wt.%, Obtained by simple mixing as a result of natural turbulence and mixing inherent in the elements used in the process. The addition of pulp in the form of a suspension of low concentration leads to an excessive amount of foamed liquid leaving the forming mesh conveyors. Excessive amount of foamed liquid is removed from the system and can be used elsewhere or processed to remove surfactants from it.

The composition may contain chemical additives introduced to change the physical properties of the paper. These chemicals are well known to those skilled in the art and can be used in any known combination. Such additives can be surface modifiers, softeners, disintegrants, hardeners, latexes, opacifiers, brighteners, dyes, pigments, adhesives, insulating chemicals, retention aids, solubility agents, organic or inorganic crosslinkers, or combinations thereof ; said chemicals may optionally contain high molecular weight alcohols, starches, polypropylene glycol (PPG) esters, polyethylene glycol (PEG) esters, phospholipids, surfactants, polyamines, HMCP, and the like.

The pulp can be mixed with substances to control the strength, for example, substances that increase strength in the wet state; dry strength enhancers; baking powder / softeners, etc. Suitable wet strength enhancers are known to those skilled in the art. A wide but not exhaustive list of suitable strength enhancing additives includes: urea-formaldehyde polymers, melamine-formaldehyde polymers, glyoxylated polyacrylamide polymers, polyamide-epichlorohydrin polymers, and the like. Thermosetting polyacrylamides are made by reacting acrylamide with diallyldimethyl ammonium chloride (DADMAC) to produce a cationic polyacrylamide copolymer, which is finally reacted with glyoxal to produce a cationic polymer, glyoxylated polyacrylamide, which provides crosslinking and increases wet strength. These substances are generally described in US Pat. No. 3,556,932, registered in the name of Coscia and others, and No. 3,556,933, registered in the name of Williams and others, incorporated herein by reference in their entirety. Polymers of this type are commercially available under the trade name PAREZ 631NC and are manufactured by Baer Corp. Various mole ratios of acrylamide / -DADMAC / glyoxal can be used to make crosslinking polymers suitable as wet strength agents. In addition, glyoxal can be replaced with other dialdehydes to communicate thermosetting wet strength characteristics. Wet strength polyamide-epichlorohydrin polymers are particularly suitable, exemplified by substances sold under the trade names Kymene 557LX and Kymene 557H manufactured by Hercules Inc. (Wilmington, Delaware, USA), and Amres® manufactured by Georgia-Pacific Resins, Inc. These polymers and a method for their manufacture are described in US Pat. No. 3,700,623 and US Pat. No. 3,772,076, each of which is incorporated herein by reference in its entirety. An extensive description of polyepihalohydrin polymers is given in Chapter 2 of Alkaline-Curing Polimeric Amine-Epichlorohydrin by Espy in Wet Strength Resins and Theier Application and edited by L. Ed. Chan, 1994), is incorporated herein by reference in its entirety. A sufficiently comprehensive list of wet strength polymers is provided by Westfelt in Cellulose Chemistry and Technology Volume 13, p. 813, 1979, which is incorporated herein by reference.

You can also use appropriate substances that temporarily give strength in the wet state. An extensive, but not exhaustive, list of suitable substances that temporarily give strength in the wet state includes: aliphatic and aromatic aldehydes, including glyoxal, malondialdehyde, succinic dialdehyde, glutaraldehyde and dialdehyde starches, as well as substituted or reacted starches, chitarchisides, dischains or other reacted polymeric reaction products of monomers or polymers containing aldehyde groups and possibly nitrogen groups. Representative nitrogen-containing polymers that can be suitably reacted with aldehyde-containing monomers or polymers include vinyl amides, acrylamides and the corresponding nitrogen-containing polymers. These polymers give a positive charge to aldehyde-containing reaction products. In addition, you can use other commercially available substances that temporarily give strength in the wet state, for example, PAREZ 745, manufactured by Bayer, together with the substances described, for example, in US patent No. 4605702.

The polymer temporarily imparting strength in the wet state can be any of a wide variety of water-soluble organic polymers containing aldehyde units and cationic units used to increase the tensile strength of products in the dry and wet state. Such polymers are described in US Pat. Nos. 4,675,394, 5,240,562, 5,138,002, 5,085,736, 4,981,557, 5,008,344, 4,603,176, 4,983,748, 4,866,151, 4,847,569 and 5,217,576. You can use modified starches sold under the trademarks CO-UZL SKREPLEN® 1000 and CO-UZL SKREPLEN® 1000 and CO-UZL SKREPLEN® 1000 and CO-UZL SKREPLEN® 1000 and CO-UZL SKREPLEN® 1000 Plus manufactured by National Starch and Chemical Co. (Bridgewater, pc. New Jersey, USA). Before use, a cationic aldehyde water-soluble polymer can be prepared by preheating an aqueous suspension containing about 5% solids, maintained at a temperature of about 240 ° F (115.56 ° C) and at a pH of about 2.7 for about 3, 5 minutes. Finally, the suspension can be quenched and diluted by adding water to form a mixture containing approximately 1.0% solids at a temperature of less than approximately 130 ° F (54.44 ° C).

Other wet temporary strength agents, also available from National Starch and Chemical Co., are sold under the trademarks CO-NODE SKREPLEN® 1600 and CO-NODE SKREPLEN® 2300. These starches are supplied in the form of aqueous colloidal dispersions and are not require preheating before use.

You can use substances that temporarily give strength in the wet state, for example, glyoxylated polyacrylamide. Substances temporarily imparting wet strength, for example, glyoxylated polyacrylamide polymers, are made by reacting acrylamide with diallyldimethyl ammonium chloride (DADMAC) to produce a cationic polyacrylamide copolymer, which is finally reacted with glyoxal to produce a cationic crosslinking polymer, which temporarily or semi-permanently gives strength when wet. These substances are generally described in US Pat. No. 3,556,932, registered in the name of Coscia and others, and in US Pat. No. 3,556,933, registered in the name of Williams and others, which are incorporated herein by reference. Polymers of this type are commercially available under the trade name PAREZ 631NC and are manufactured by Baer Industries. Various mole ratios of acrylamide / -DADMAC / glyoxal can be used to make crosslinking polymers suitable as wet strength agents. In addition, glyoxal can be replaced with other dialdehydes to communicate thermosetting wet strength characteristics.

Suitable dry strength agents include starch, guar gum, polyacrylamides, carboxymethyl cellulose, and the like. Particularly suitable is carboxymethyl cellulose, for example, sold under the trade name Hercules CMC, manufactured by Hercules Inc. (Wilmington, Delaware, USA). According to one embodiment, the pulp may contain from about 0 to about 15 lb / t of a dry strength agent. According to another embodiment, the pulp may contain from about 1 to about 5 lb / t of a dry strength agent.

Suitable disintegrants are also known to those skilled in the art. Baking powder or softeners can also be introduced into the pulp or sprayed onto the fibrous layer after it is formed. Softeners may also be used according to the present invention, including, but not limited to, a class of amidoamine salts derived from partially amine-neutralized amines. Such substances are described in US patent No. 4720383. In the works of Evans, Chemistry and Industry, 5 July 1969, pp. 893-903; Egan, J. Am. Oil Chemist's Soc ., Vol. 55 (1978), pp. 118-121; and Trivedi et al., J. Am. Oil Chemist's Soc., June 1981, pp. 754-756, incorporated in their entirety into the present application by reference, it is said that softeners are often commercially available only as complex mixtures, rather than as separate compounds. Although the focus of the description below is on the prevailing species, it should be understood that commercially available mixtures can, in general, be used in practice.

Quasoft 202-JR is a suitable softener, which can be obtained by alkylation of the condensation product of oleic acid and diethylene triamine. Under synthesis conditions in which there is a shortage of an alkylating substance (e.g. diethyl sulfate) and only one alkylation step is carried out after adjusting the pH to protonate unleaded substances, the result is a mixture consisting of cationic ethylated and cationic unleaded substances. A small portion (for example, about 10%) of the obtained amidoamine is cyclized to imidazoline compounds. Since only the imidazoline parts of these substances are Quaternary ammonium compounds, the compositions as a whole are pH-sensitive. Thus, in the practical use of this class of chemicals according to the present invention, the pH in the headbox should be approximately 6-8, more preferably 6-7, and most preferably 6.5-7.0.

Quaternary ammonium compounds, for example, dialkyl dimethyl quaternary ammonium salts, are also suitable, especially if the alkyl groups contain about 10-24 carbon atoms. These compounds have the advantage of being relatively immune to pH.

Biodegradable softeners may be used. Representative biodegradable cationic softeners / disintegrants are disclosed in US Pat. Compounds are biodegradable quaternary ammonium compound diesters, quaternized amine esters and biodegradable vegetable oil based esters, reacting with quaternary ammonium chloride and ammonium dierucyl dimethyl chloride double esters are biodegradable.

In some embodiments, a particularly preferred disintegrant composition comprises a quaternary amine component as well as a nonionic surfactant.

The original fibrous layer is usually dehydrated on paper cloth. You can use any suitable cloth. For example, the cloth may contain a two-layer base fabric structure, a three-layer fabric base structure, or a laminated fabric base structure. Preferred cloths are cloths having a laminated base woven structure. The wet press cloth, which may be particularly suitable for carrying out the present invention, is Vector 3 cloth manufactured by Voith Fabric. Analogs of press felts are described in US patents, including Patent Nos. 5657797, 5368696, 4973512, 5023132, 5225269, 5182164, 5372876 and 5618612. You can also use a press cloth of a different structure described in US patent No. 4533437 registered in the name of Curran and others .

Any suitable creping tape or cloth may be used. Suitable creping fabrics include monolayer, multilayer, or composite fabrics, preferably having a sparse structure. The fabrics may have at least one of the following characteristics: (1) from the side of the creping fabric in contact with the fiber layer in the wet state (from the “upper” side), the number of threads per inch in the longitudinal direction (tissue density on the basis of ) is from 10 to 200, the number of threads per inch in the transverse direction (tissue density in the weft) is also from 10 to 200; (2) the diameter of the thread is usually less than 0.050 inches; (3) on the upper side, the distance between the highest inflection point of the warp and the highest inflection point of the weft is from about 0.001 inch to about 0.02 inch or 0.03 inch; (4) between these two levels there can be kinks formed either by warp or weft threads, which give the topography of the fabric a three-dimensional appearance, containing elevations and depressions, which communicates with the fibrous layer during the wet forming stage; (5) the fabric can be oriented in any suitable way so that the desired effect is achieved during the process and the desired properties are communicated to the product; bends of the longitudinal warp yarns may be on the upper side to increase the protrusions in the longitudinal direction in the product, or the longitudinal grooves may be located on the upper side, if it is desirable to obtain more protrusions in the transverse direction to influence the creping characteristics when transferring the fibrous layer from the transfer cylinder to creping fabric; (6) the fabric can be made so that certain geometric patterns are obtained that are favorably perceived by the eye, which are usually repeated between every 2-50 warp threads. Suitable commercially available coarse fabrics include a number of fabrics manufactured by Voith Fabrics.

The creping fabric may thus be of the class described in US Pat. No. 5,607,551 (columns 7-8), registered in the name of Farrington et al., As well as in US Pat. No. 4,239,065, registered in the name of Trokhan, and in US Pat. No. 3974025 registered in the name of Ayers. Such fabrics may contain from about 20 to about 60 warp threads per inch, and are made from polymer monofilaments having diameters typically ranging from about 0.008 to about 0.025 inches. The main and weft monofilaments can have (but this is not a requirement) the same diameter.

In some cases, the monofilaments are intertwined in this way and give them such a complementary curved configuration at least in the direction of the Z axis (in the direction of the thickness of the fabric) to create the first group, or array, located in the same plane of the crosshairs of both groups of monofilaments located in the upper plane, and a predefined second group, or array, of crosshairs located under the upper surface. Arrays are distributed in such a way that parts of the crosshairs located in the upper plane define an array of depressions, similar to those found in a basket of willow twigs, on the upper surface of the fabric, and these depressions are staggered both in the longitudinal and transverse directions , and so that each depression overlaps at least one crosshair located under the upper surface. The depressions are discrete around the perimeter surrounded in plan view by columnar clusters containing parts of a plurality of crosshairs located in the plane of the upper surface. The fabric loop may contain thermofixed monofilament of thermoplastic material; the upper surfaces of the crosshairs located in the same plane, located in the upper plane, can represent a one-plane flat surface. Particular embodiments of the invention include satin weaves as well as hybrid weaves of three or more warp systems, and warp and weft densities may be from about 10 × 10 to about 120 × 120 monofilaments per inch (4 × 4 to about 47 × 47 per centimeter). Although the preferred density range for warp and weft is from about 18 × 16 to about 55 × 48 monofilaments per inch (from 9 x 8 to about 22 × 19 per centimeter).

Instead of a pressing fabric, a drying machine fabric may be used as creping if desired. Suitable fabrics are described in US Pat. Nos. 5,449,026 (fabric) and No. 5690149 (longitudinally spun ribbons of filaments) registered in the name Lee, and also US Pat. No. 4,490,925 registered in the name Smith (spiral structure).

The adhesive used for creping on the cylinder of the Yankee dryer should preferably be compatible with the fiber layer with an average moisture value to improve the transfer process from the creping fabric to the cylinder of the Yankee dryer and to reliably bond the fiber layer to the cylinder of the dryer “ Yankee ", since the fibrous layer is dried to a dryness of 95% or more on a cylinder, preferably in a large-volume drying chamber, the properties of the adhesive are very important to ensure a stable This machine can be used at high speeds, and it is hygroscopic, it can be rewet, it is essentially not a crosslinkable adhesive, examples of preferred adhesives include those containing ordinary polyvinyl alcohol described in US patent No. 4528316 registered in soerens et al., other suitable adhesives are disclosed in concurrently pending U.S. Patent Application No. 60/372255, filed April 12, 2002, entitled "Improved Crepe Adhesive Modifier substance and the method of manufacturing products ”(case No. 2394), the essence of patent No. 4528316 and application No. 60/372255 are incorporated into this application by reference, suitable adhesives are optionally provided with modifiers, etc., preferably a small amount of crosslinking agent is used or not to enter it at all in the adhesive in many cases; so that the polymer is not substantially crosslinkable in use.

The present invention is illustrated by reference to the drawings, especially in Figs. 1 and 2. Fig. 1 shows a cross-section (120-fold increase) (along the longitudinal direction of the creping fabric) of the web 10, where the columnar region 12 is visible as a cluster of fibers, that the fibrous layer contains micro folds located in the transverse direction to its longitudinal direction, i.e. protrusions or folds extending in the transverse direction (in the photograph), it should be borne in mind that the fibers in the region 12 of the accumulation of fibers have an orientation inclined in the transverse direction, especially on the right side of the region 12, where the fibrous layer is in contact with the fold of the creping fabric . The difference between the flow rates and the forming mesh conveyor (flow rate is (minus) the speed of the mesh conveyor) has a significant effect on the relative tensile strength, as shown in figure 2, and this effect is noticeably different from that observed in conventional products obtained by pressing in the wet state.

Figure 2 presents a diagram of the dependence of the relative tensile strength (the ratio of tensile strengths in the longitudinal and transverse directions) on the difference in speed (ft. / Min) of the flow of the composition poured from the headbox and the forming mesh conveyor. The upper U-curve is typical of a conventional absorbent web processed in a wet press (CWP). The lower, wider curve is typical of a creped product according to the invention. According to FIG. 2, it can be easily determined that relative tensile strengths of less than 1.5 or about this value are achieved according to the invention in a wide range of differences in flow rates and the mesh conveyor, i.e. in a range that is more than two times the range of the CWP curve shown (conventional wet pressing). Thus, by adjusting the ratio of the flow rates of the composition to be let in from the headbox and the forming mesh conveyor, it is possible to achieve the desired properties of the web.

When considering FIG. 2, it is also seen that the tensile strength ratios in the longitudinal and transverse directions of less than 1 are difficult or impossible to obtain with conventional wet-pressing the fibrous layer (CWP). In addition, webs with such ratios of 1 or less than 1 are obtained by applying the present invention without the formation of many fiber complexes, or "flakes", which is not typical for conventional canvases processed on a wet press (CWP), with small relative tensile strength values. This difference occurs, in part, because relatively small speed differences are required to achieve low tensile strengths during the normal processing of the fibrous layer in a wet press (CWP), and possibly in part because the fiber is redistributed to creping fabric during creping during transfer from a transmission surface according to the invention.

The properties of many canvases in the transverse direction are more important than the properties in the longitudinal direction, this is especially true for commercially available canvases in the form of towels, the strength of which in the transverse direction in the wet state is very significant. The main cause of damage to products is a “breakthrough” or separation of only a piece of towel, rather than damage to the entire canvas. According to the invention, the relative tensile strength of the web in the transverse direction can be selectively increased by adjusting the difference in the flow rates from the headbox and the forming mesh conveyor and creping with a fabric.

Figure 3 presents a photograph (10-fold increase) crepe on the fabric of the fibrous layer from the side of the fabric. In FIG. 2 that the web 10 contains a plurality of very distinct areas of high density fiber clusters 12 containing fibers oriented obliquely to the transverse direction (PN) connected by relatively low density regions 14 containing fibers oriented obliquely in the direction between columnar regions or areas of fiber accumulation.

The inclination of the orientation is also seen in Figure 1, especially where the fibers of the columnar regions, or the clusters of fibers 12 inclined in the transverse direction, were cut when preparing test samples in the center of the region 12. To the left of the region 12, in the connecting region, it is seen that the fiber is more inclined along the longitudinal direction between the areas of accumulation of fibers. These features are also easy to see in FIG. 3 at a lower magnification, where the inclination of the fibers in regions 14 is directed between the columnar regions.

Figure 4 presents the technological scheme of the paper machine 15, comprising: a conventional two-mesh forming part 17; cloth 19; press part 16 with a shoe; creping fabric 18 and a Yankee dryer 20 suitable for practicing the present invention. The forming part 12 comprises: a pair of forming fabrics 22, 24 supported by a plurality of shafts 26, 28, 30, 32, 34, 36 and the forming shaft 38. Using the pressure box 40, a mass composition in the form of flow is fed into the contact zone 42 between the forming shaft 38 and shaft 26 and fabrics. Regulation of the flow rate relative to the speed of the forming fabrics is an important aspect of the regulation of tensile strength, as should be clear to a person skilled in the art. An initial fibrous layer 44 is formed from the composition, which is dehydrated on the tissues by suctioning a liquid, for example, using a suction box 46.

The initial fibrous layer is transported to paper cloth 48 supported by a plurality of shafts 50, 52, 54, 55, the cloth being in contact with the shoe press shaft 56. The fibrous layer when transferring it to the cloth has a low dryness. The transfer process can be facilitated by suction; for example, the shaft 50 may be a suction shaft, if desired, or a receiving or shoe vacuum shaft, known in the art. When the fibrous layer reaches the shoe press shaft, it may have a dryness of 10-25%, preferably 20-25% or so, at the entrance to the contact zone 58 between the shoe press shaft 56 and the transfer shaft 60. The transfer shaft 60 may be a heated shaft, if desired. Instead of the shaft 56 of the shoe press, the shaft 56 may be a conventional suction press shaft. If a shoe press is used, then it is desirable and preferable that the shaft 54 be a suction roll by which water can be removed from the cloth before the cloth enters the contact zone of the shoe press, since in the contact zone of the shoe press water is squeezed out of the composition into the cloth. In any case, the use of a suction shaft or a suction rotary shaft (OPV) in zone 54 is usually desirable to provide conditions under which the fibrous layer remains in contact with the cloth during the change of direction, as shown in the drawing, and should be clear to the person skilled in the art area.

The fibrous layer 44 is wet-pressed on a cloth in the contact zone 58 using a press shoe 62. The fibrous layer is thus dehydrated with a seal in zone 58, typically increasing dryness by 15% or more at this stage of the process. The structure shown in zone 58 is generally referred to as a “shoe press”; according to the present invention, the cylinder 60 acts as a transfer cylinder by which the fibrous layer 44 is transported at a high speed, typically 1000-6000 ft./min (304.8-1828.8 m / min), to the creping fabric.

The cylinder 60 has a smooth surface that can be provided with adhesives and / or release agents, if required. The fibrous layer 44 adheres to the transfer surface 64 of the cylinder 60, which rotates at a high angular velocity while continuing to transport the fibrous layer in the longitudinal direction of the machine, indicated by arrows 66. On the cylinder, the fibrous layer 44 has a generally apparent random distribution of fiber.

Direction 66 is here called the longitudinal direction (Pr) of the paper machine 10, as well as the longitudinal direction (Pr) of the fibrous layer; while the transverse direction (PN) of the machine in the plane of the fibrous layer is perpendicular to the longitudinal direction (Pr).

The fibrous layer 44 is introduced into the contact zone 58, usually at a dryness of 10-25% or so, and is dehydrated and dried to a dryness of about 25 to about 70 during the time during which it is transferred to the creping fabric 18, as shown in the drawing .

The fabric 18 is supported by a plurality of shafts 68, 70, 72 and a press roll or rigid press roll 74 so as to form a contact zone 76 between the creping fabric and the transfer cylinder 60, as shown in the drawing.

The creping fabric defines a creping contact area at a distance within which the creping fabric 18 may be in contact with the shaft 60; those. significant pressure is applied to the fiber layer adjacent to the transfer cylinder. To this end, the support (or creping) shaft 70 can be provided with a soft deformable surface, due to which it is possible to increase the length of the creping contact zone and increasing the creping angle of coverage formed between the creping fabric and the web and the contact point, or the shoe press shaft can be used as a shaft 70 to increase effective contact with the fiber layer in the contact zone 76 of the high pressure creping fabric, where the fiber layer 44 is transferred to fabric 18 and transported in the longitudinal direction of the machine. By using various equipment in the creping contact area, it is possible to adjust the creping angle of the tissue or exit from the creping contact area. Thus, it is possible to influence the nature and degree of fiber redistribution, delamination / loosening, which can occur in the creping contact zone 76 of the fabric, due to the regulation of the parameters of this contact zone. In some embodiments, it may be desirable to restructure the interfiber characteristics in the z-axis direction, while in other cases it may be desirable to affect properties only in the plane of the fiber layer. By means of the parameters of the creping contact zone, it is possible to influence the distribution of the fiber in the fiber layer in a number of directions, including changes in the direction of the z axis, as well as in the longitudinal and transverse directions. In any case, the transfer from the transfer cylinder to the creping tissue is a powerful influence factor, namely that the tissue is transported at a lower speed than the fibrous layer, and a significant change in speed occurs. Typically, the fibrous layer is creped in the range of about 10-60% and even more during transfer from the transfer cylinder to the fabric.

The creping contact area 76 typically extends at a distance greater than the creping contact area of the tissue by about 1 / 8-2 inches, typically in the range of 1 / 2-2 inches. When using creping fabric with a weft density (Density) of 32 threads / inch, the fibrous layer 44 therefore collides in the contact zone with about 4-64 weft monofilaments somewhere.

The pressure in the contact zone 76, i.e. the pressure between the support shaft 70 and the transfer shaft 60, respectively, is 20-100 lbs / p. inch, and preferably 40-70 lb / p. inch.

After transferring the fibrous layer from the creping fabric, it continues to be transported in the longitudinal direction 66, where it is wet-pressed on the cylinder 80 of the Yankee dryer in the transfer contact zone 82. The transfer in the contact zone 82 is carried out when the fiber layer is dry, usually in the range of from about 25% to about 70%. With such dryness, it is difficult to sufficiently reliably adhere the fibrous layer to the surface 84 of the cylinder 80 to completely remove the fibrous layer from the fabric. Typically, an adhesive composition containing polyvinyl alcohol / polyamide is applied in area 86, as described above, if desired.

In zone 67, a suction box can be used to increase the thickness of the treated fibrous layer, if desired. Typically, a vacuum of about 5 inches to about 30 inches of mercury is used.

The fibrous layer is dried on a cylinder 80 of the Yankee dryer, which is a heated cylinder, and impact by high-speed jets of air in the chamber 88 of the Yankee dryer. When the cylinder rotates, the fibrous layer 44 is creped when it is removed from the cylinder using a creping blade 89 and wound onto the take-up shaft 90. The creping of the fibrous layer at the outlet of the Yankee dryer can be done using a wave creping scraper, for example, disclosed in US Patent No. 5690788, the essence of which is incorporated into this application by reference. It was shown that the use of a wave-like creping scraper allows you to get some advantages in the manufacturing process of thin paper. In general, thin paper creped using a wave-like scraper has a greater thickness, increased elongation in the transverse direction and greater porosity than comparable types of thin paper made using conventional creping scrapers. All these changes achieved through the use of a wave-like scraper tend to correlate with an improved perception of softness of tissue products.

Optionally, a calender 85 is installed with shafts 85 (a), 85 (b) for calendering the web, if desired.

If the creping process is carried out in a wet state, then instead of a Yankee dryer, you can use a dryer with shock jets of air, a dryer with suction, or many drum tumble dryers. Impact air dryers are disclosed in the following patents and applications, the essence of which is incorporated into this application by reference: US Patent No. 5865955, registered in the name of Ilvespaaet et al., US Patent No. 5968590, registered in the name of Ahonen et al., US Patent No. 6001421, registered in the name of Ahonen and others, US patent No. 6119362, registered in the name of Sundqvist and others, application for US patent No. 09 / 733,172, entitled "The drying process during creping in the wet state using shock jets of air for the manufacture of absorbent canvas "Now United States Patent number 6,432,267.

A suction dryer is well known in the art and is described in US Pat. No. 3,432,936, registered to Cole et al., The disclosure of which is incorporated herein by reference; US Pat. No. 5,851,353 discloses a drum drying system.

Representative examples

Using equipment of the usual class shown in Figure 4, an absorbent sheet was made with different densities, creping degrees, etc. This web was observed a large elongation in the transverse direction at low values of relative tensile strength in the dry state, as is clearly shown in Fig.5-9. As follows from the previous description and the following examples, the relative density of the areas of accumulation of fibers and connecting regions, the degree of columnarity, the orientation of the fibers and the geometry of the mesh structure are controlled by the appropriate selection of substances and tissues, as well as by controlling the degree of creping on the fabric, the contact zone parameters and the difference in flow rates mesh conveyor.

Representative production data are summarized in Table 1 for the base web and in Table 2 for the converted web.

The following abbreviations are sometimes found in the following Tables and Examples:

BRT Toilet paper CD, MD Tensile strength (in the absence of additional instructions) in the longitudinal and transverse directions CD%, MD% Elongation in the longitudinal and transverse directions SMS Carboxymethyl cellulose Cwp Conventional wet pressing (OMS) FC Crepe on fabric or the degree of crepe on fabric GM, GMT Geometric mean (SG) value, usually the geometric mean tensile strength (SGP) Mod Module Ratio Relative tensile strength in the dry state, SPR Hard press shaft, shaft 74 (see Figure 4) STR Suction rotary shaft, shaft 54 (OPV) (see Figure 4) T Ton (t) Tad Dry air drying (SPV) 819 Embossing Pattern According to US Patent No. 6827819

Products such as tissue paper

Products such as thin paper (varieties with variable wet strength, for which softness is a leading parameter), made with a high solids content when creped onto fabric, as described in this application; you can use many of the same parameters that are used in the manufacture of products in the form of towels (varieties with constant strength in the wet state, for which absorption capacity is an important parameter, strength in use is a very significant parameter, and softness is a less significant parameter than for varieties thin paper). In each category, single-layer and two-layer products can be made.

Fibers

Products such as soft tissue paper are optionally made using large quantities of hardwood fiber. This fiber is not as coarse as the longer and stronger fiber of softwood. In addition, these thinner, shorter fibers are much more in 1 gram of fiber. The negative side of these fibers is that the pulp of hardwood generally contains a greater number of small fragments of fibers, which is a characteristic feature of the structure of the wood from which the pulp is made. Removing these small fragments of fibers can lead to an increase in the number of real fibers present in the finished web. In addition, the removal of these small fragments of fibers leads to a decrease in the bonding potential during drying, facilitating the loosening of the web either with chemicals or with a scraper that secures the paper at the exit of the paper machine. A significant advantage of the fact that 1 gram of pulp contains a large number of fibers is the opacity or low transparency of the paper. Since most of the properties of thin paper are visually evaluated even before they are touched, this optical property is an important factor in the perception of quality. Softwood fibers are typically required to create a mesh-like structure on which hardwood fibers can be deposited to obtain optimal softness and optimal optical properties. But even in the case of softwood, the coarseness of the fiber and the number of fibers in 1 gram of fiber are important characteristics. Although softwood, such as northern softwood, contains long, thin, flexible fibers, their amount per gram of fiber is much larger than long, coarse, thick, hard fibers of southern softwood. The net benefit from the choice of fibers is that with this technology, as with all others, when using northern softwood and with a small number of small fragments of fibers, coarse hardwood fibers, for example, eucalyptus, they get softer paper with a given tensile strength than when using wood of northern hardwoods, and, especially, when using wood of southern hardwoods.

Chemical substances

In the manufacture of thin paper, in general, a wide range of chemicals are used to meet consumer requirements for their functional properties and softness. In general, it is much preferable to inject chemicals to increase dry strength in a portion of a pulp mixture containing long fiber than to use a refiner to increase softness. When refining, small fragments of fibers are formed, and there is a tendency to the formation of a greater number of bonding nodes with a higher bonding strength, since when refining, the fibers become more flexible, which leads to an increase in the potential for the fibers to come into contact with each other during drying. On the other hand, additives that increase the strength in the dry state, increase the strength of the possible knots without increasing the number of knots. Such a fabric initially has greater flexibility even up to the stage of creping on the fabric in the process of creping on the fabric. The introduction of a loosening chemical into a part of hardwood is desirable since these hardwood fibers are less prone to bonding to each other, but retain the ability to attach softwood fibers to the net, i.e. at their expense, they mainly provide paper tensile strength. In some cases, you can also add substances that temporarily give strength in the wet state, together with fibers of softwood and hardwood to improve the perception of substances that give strength in the wet state, without sacrificing leachability or safety of the tank with the septic tank.

Crepe on fabric

Thanks to this stage of the process, the unusual and desirable properties of the thin web are mainly provided. An increase in the degree of creping on the fabric leads to an increase in thickness and a decrease in tensile strength. In addition, creping on the fabric leads to a change in the relative tensile strength of the base webs and makes it possible to obtain webs with the same tensile strength in the longitudinal and transverse directions or webs with lower tensile strength in the longitudinal direction than in the transverse direction. However, it is desirable that the thin paper has the same tensile strength in two directions, since the largest number of products is used regardless of the direction of the web. For example, the “piercing” of thin paper is influenced by this relative tensile strength along with the fact that due to creping on the fabric, the elongation in the transverse direction increases, especially at lower values of the ratio of strengths in the longitudinal and transverse directions, in comparison with the usual technology. With other technologies, it is difficult to carry out the processing of a fiber layer having the same tensile strength in both directions on high-speed technological equipment due to a tendency to tear starting from the edge and tending to spread in the transverse direction of the web, causing a break. In contrast to conventional products, creped onto fabric webs with the same relative tensile strength, made according to the invention, retain a tendency to tear in the longitudinal direction, thus showing a tendency to self-repair if an edge tear occurs and begins to spread in the fabric. This unexpected and unusual property, together with the tensile strength embedded in the fabric at this stage, which is supposed to be stretched, allows for efficient, high-speed operations with a relative tensile strength equal to or less than one. In addition, due to the same properties, they achieve a clear separation along the perforations in the finished product. Levels of creping on tissue paper tissue range from about 30% to about 60%. Although higher levels are possible, a wide range of quality levels can be achieved within these limits without changing the performance of the paper machine.

Fabrics

The structure of the tissue is a distinct aspect of the proposed method. But other fabric parameters follow their importance behind the size and depth of the depressions formed during weaving. Their shape and location are also very important. The diameters of the threads of which the fabric is made are also important. For example, by the size of the inflection of these threads at the leading edge of the cavity into which the web is to be creped, the creping degree on the fabric and the density at which holes appear in the web are determined. The problem, especially with grades of thin paper, is to make these depressions as deep as possible using filaments of the smallest possible diameters, thus making it possible to achieve large degrees of creping on the fabric, resulting in large thicknesses of sheets at a given ratio. Obviously, the structure of the fabric needs to be changed depending on the density of the fabric, which is supposed to be made. For example, two-ply toilet paper of very high quality, with high strength, great thickness and softness, can be made on fabric model 44M. The 44G fabric can also be used to make a heavier (up to 2 times) single layer web with very good results. Another distinctive feature of the structure of the fabric is that by means of it a drawing is made in the canvas. Some structures of fabrics can produce a very noticeable pattern, while others can produce patterns that seem to disappear in the background of the canvas. Often, consumers want the embossed pattern to be visible on the canvas during processing, and in these cases a smaller pattern may be more desirable on the canvas. Some grades of paper can be made without embossing, and therefore a more distinctive pattern, made at the creping stage on the fabric, helps to give a "magnificent" appearance to the canvas. Consumers tend to consider ordinary canvases products of lower quality and lower cost.

Creping

Since in a typical creping process on fabrics according to the invention, the web is transferred to a Yankee dryer for final drying, the web can (and usually is) be creped at the outlet of this dryer to further increase its softness. The advantages of thin paper are largely determined by the creping stage, by which the thickness and softness of the canvas are increased. This is particularly facilitated by the smooth surface of the canvas from the side facing the working body of the Yankee dryer. In addition, since the degree of creping on the coast and the degree of creping on the fabric can be varied regardless of productivity (from the speed of winding on the coast), there is a significant breadth of possibilities for changing the properties of the finished web. An increase in the ratio of the degree of creping on the roll to the degree of creping on the fabric leads to a decrease in the difference in properties on both sides of the paper (two-sided), since a lower degree of creping on the fabric is introduced to change the level of elongation in the longitudinal direction. Less noticeable “brow-like” structures are formed in paper, which can cause two-sidedness. In addition, an increase in this ratio also leads to an increase in the opacity and perception of the web as thicker at the same thickness (determined by measurement). It is often desirable to maintain an acceptable ratio (say, 25-50% creping on the roll to 50-75% creping on the fabric) to improve consumers' perception of these “intangible” properties associated with the visually perceived appearance of the canvas.

Calendering

According to all calculations, the more calendaring is performed, the better, to the extent that an acceptable level of web thickness for subsequent transformations is maintained. Too small thicknesses require too much embossing, which subsequently leads to a general violation of quality. Thus, one strategy for producing high-quality toilet paper is to use the coarsest fabric without forming holes in the fabric with a decrease in the level of creping on the fabric so that most of the elongation in the longitudinal direction is ensured by the proportion of creping on the roll and still sufficient thickness before calendering so that at least about 20-40% of this thickness can be reduced during the calendering stage. At such levels of calendering, there is a tendency to reduce the difference in properties on both sides (versatility) of the paintings. In an alternative embodiment, a high-quality web can be made using a thinner fabric, but with a lower ratio of crepitation on the roll to the degree of creping on the fabric. Since, using thinner fabric, smaller elevations are formed, and more creping on the fabric can be made to obtain the desired thickness without unduly increasing versatility. In most cases, a reduction in versatility is achieved. In this scenario, the ratio of the degree of creping on the coast to the degree of creping on the fabric can be no more than about 5-10%. The degree of calendering can be maximized to achieve the desired softness. This method is desirable when relatively strong fibers are used, since when creping on the fabric, the tensile strength is greatly reduced, and when due to the structure of the fabric, the two-sidedness of the fabric is less than the average value.

Towel Products

Products in the form of towels behave during processing in a similar way to tissue paper under various parameters. However, in many cases, when processing products in the form of towels, the same parameters are fulfilled, but in the opposite direction, while some parameters are performed in the same direction. For example, it is desirable that both of these types of products have a sufficient thickness, since the thickness is directly related to the softness of thin paper and the absorption capacity of towels. In the following description, only those parameters are considered in which differences from the corresponding parameters of thin paper are observed.

Fibers

Towels, when used, must have functional strength, which usually means strength when wet. To achieve these required values of tensile strength, long fibers of softwood are used in proportions opposite to those used in thin paper. Typically, 70-90% softwood fiber is used. Refining can be used, but at the same time there is a tendency to clog the web so hard that with subsequent creping on the fabric it is impossible to “loosen” the structure. This results in slower absorption and smaller volumes of absorbed liquid. In contrast to thin paper, small fragments of fibers can be used in a towel cloth, so that too much hardwood fiber is not used, since again there is a tendency to clog the fabric structure, as well as to reduce its tensile strength.

Chemical substances

It unexpectedly turned out that in the manufacture of cloths for towels, you can also use baking powder. But their application should be carried out prudently. Similarly, fiber refining should be done at lower levels to maintain the loose structure of the web and its ability to rapidly absorb. Thus, chemicals are added in the accepted order to increase strength. Of course, wet strength chemicals should be added to prevent tearing during use. But to achieve higher levels of tensile strength in the wet state, the ratio of tensile strength in the wet state to tensile strength in the dry state should be increased to a maximum. If the tensile strength becomes too large, the towel cloth becomes too “paper-like”, consumers consider it a poor quality product. Thus, wet strength chemicals and carboxymethyl cellulose (CMC) are added to increase the ratio of wet tensile strength to dry tensile strength in amounts ranging from a typical 25% up to a desired range of 30-35% . In addition, for the manufacture of a softer fabric and, therefore, perceived by consumers as higher quality, a baking powder can be added, with which it is preferable to reduce the tensile strength in the dry state in the transverse direction relative to the tensile strength in the wet state. Baking powder and softeners can also be applied by spraying on the canvas after drying to further improve its touch properties.

Crepe on fabric

An increase in the degree of creping on the fabric directly leads to an increase in absorption capacity. Thus, it is desirable to maximize the degree of creping on the fabric. However, with an increase in the degree of creping on the fabric, the tensile strength also decreases, therefore, it is necessary to maintain a balance between these parameters. Towel sheets sometimes may not have high elongations in the longitudinal direction due to the type of towel dispenser used. In these cases, the degree of creping on the fabric should also be limited. Thus, towels generally require the use of a fabric of a coarser structure than creping thin paper. In addition, since these webs in the wet state usually have significant wet strength, it can be more difficult to form them with the same dryness as the webs of thin paper.

Fabrics

In general, coarse fabrics are desirable for making towels. Bilayer towels for towels are usually made with good results on 44G or 36G fabrics or on coarse fabrics, although good results can be obtained with thinner fabrics, especially if the creping rate is increased. For the manufacture of single-layer webs, even coarser fabrics and other techniques are often required to produce an acceptable weave. The presence of a longer fiber in the canvases and the greater strength of the canvases allow the use of these fabrics and a higher degree of creping on the fabric until holes appear in the canvases.

Creping

Towel sheets are subjected to a very small degree of creping. Crepe must increase the thickness, but this must be done in the same way as in the case of conventional wet pressing (OMS) of the webs. This thickness disappears upon wetting, and the web expands. With the thickness achieved as a result of creping on the fabric, the same thing happens as with a dry sponge when wet. The canvas expands in the direction of the Z axis and can seat in the longitudinal and transverse directions. This behavior significantly contributes to the susceptible absorption capacity of towels and makes them similar in appearance to towels obtained using drying with air suction (SPV). In many cases, the use of serrated scraper according to Taurus technology in conjunction with the process of creping on the fabric helps to improve the absorption capacity, increase the thickness and softness of the towel web. The stiffness in the transverse direction decreases, while the relative elongation in the transverse direction increases. The greater the thickness achieved on the scraper, the greater the degree of calendering becomes possible and, therefore, achieving greater smoothness of the canvas. In some cases, it is desirable to draw the web away from the working surface of the Yankee dryer without creping. This may be the case when making towels for wiping hands in public toilets, where softness is less important than wrapping more linen in a roll. See U.S. Patent No. 6,187,137, registered in the name of Druecke et al., And also pending U.S. Patent Applications filed simultaneously with this application.

Calendering

Calendering towels achieve two main goals. Firstly, when calendaring, they smooth the canvases and improve their perception by touch. Secondly, the elevations formed under the influence of the fabric “destroy”, giving the canvas a greater depth to the touch in the direction of the Z axis and often improving the absorption capacity at a given thickness.

The list of data obtained during the testing of thin paper

For the manufacture of single-layer toilet paper for retail and commercial use, some equipment of paper machines and equipment for embossing drawings were used. The variables included: the degree of creping on the fabric (%), the degree of creping on the roll (%), the level of addition of the softener, the type of softener, the place of application of the softener, the type of fiber, the ratio of the amount of hardwood (TD) fiber and softwood (MD), calendering pressure, calendering with rubberized and steel shafts, type of creping fabric, longitudinal and transverse tensile strength ratio and chemicals applied to the working surface of the dryer s "Yankees." Embossed drawings included: “Two Hearts” according to US Pat. No. 819, “M3”; "Butterflies and whirlwinds"; “Butterflies and whirlwinds with micro” and “Mosaic flower iris”. The prototype of the best commercial single-layer thin paper (TB), containing 40% of northern hardwood fiber (VSPTD) and 60% of secondary fiber, at a density of 20 pounds and an SGRP of 450, reached a soft touch rating of 17.5 points. When defining the properties of the prototype of the best single-layer toilet paper (BRT) for retail, containing 80% southern hardwood fiber (TD) and 20% southern softwood fiber (MD), at a density of 20.5 pounds and SGR = 450, achieved a soft touch of 16.9 points.

The research objectives included the definition of: process requirements in the manufacture of single-layer toilet paper for retail sale with a soft touch of 17.0 points, using fiber of the southern breeds TD and MD; process requirements in the manufacture of single-layer commercial thin paper with a soft touch of 17.0 points, when using fiber TD and recycled fiber; the influence of fiber and other process variables on softness to the touch and physical properties of the webs.

Commercial single layer toilet paper with a target softness of 17.0 points was obtained at a density of 20 pounds. Tests of consumer properties showed the effect of reduced density on consumers' acceptance of this product.

When using the fibers of the southern breeds TD and MD for the manufacture of single-layer toilet paper for retail sale, at a density of 21.4 lbs / 3000 square meters. ft, the greatest softness to the touch achieved with SGRP = 450 was 16.9 points.

When using the fibers of the southern breeds TD and MD for the manufacture of single-layer toilet paper for retail sale, at a density of 20.5 lbs / 3000 square meters. ft, the greatest softness to the touch achieved with SGRP = 450 was 16.9 points.

Using 40% TP wood fiber and 60% secondary fiber (WB) for the manufacture of single-layer commercially available thin paper at a density of 20.2 lb / 3000 sq. ft, the greatest softness to the touch achieved with SGPR = 450 was 17.5 points. In all the work, the results of which are given here, the average softness to the touch was 16.9 points. When using 100% recycled fiber (WB) for the manufacture of single-layer commercially available thin paper PS at a density of 22.1 lb / 3000 sq. ft, the greatest softness to the touch achieved with SGPR = 450 was 16.4 points.

When using fibers of Aracruz TD and MD Marathon for the manufacture of single-layer thin paper for retail sale at a density of 19.8 lb / 3000 square meters. foot, the greatest softness to the touch achieved with SGPR = 450 was 18.3 points. In all the work, the results of which are given here, the average softness to the touch was 18.0 points.

As a result of calendering with steel shafts (steel / steel), a more significant decrease in thickness was achieved at equivalent pressure and higher softness to the touch than with calendering with a rubber shaft and steel shaft (rubber / steel).

The increase in pressure during calendering was manifested in an increase in softness to the touch, but calendering at pressures of more than 65 psi. inch can lead to a decrease in softness when using primary fiber TD and secondary fiber. When using fiber TD and MD pressure of 80 pounds / p. inch may be the upper limit.

With a constant degree of creping on the production line, an increase in the degree of creping on the fabric leads to an increase in the elongation in the transverse direction and to a decrease in the fracture modulus. However, this parameter does not affect the softness to the touch of the finished product with a constant value of SGR.

With a constant degree of creping on the production line, varying the degree of creping on the fabric with respect to the degree of creping on the roll does not affect the softness of the touch.

The types of creping fabrics used in this study had an effect on the thickness of the base fabric, but did not have a significant effect on softness to the touch. When using fabric with a large mesh structure, a base fabric of a greater thickness was obtained, which allowed calendering to a greater extent.

Single layer toilet paper with a ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction equal to 1.0 (tensile strength in the longitudinal direction is equal to tensile strength in the transverse direction), was equivalent in softness to the touch of single layer toilet paper with ordinary the ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction of 1.8 (with higher tensile strength in the longitudinal direction nii). In this case, the softness depended on the SPS. But not from strength or module in the transverse direction.

The effect of composition

The fiber blends shown in Tables 3 and 4 were processed under the same process conditions and single layer toilet paper was made. The softness to the touch was determined and the process was adjusted so as to provide an SGR value of 450 using the strength-softness values from the Appendix according to the formula: (softness to touch) + ((450-SGR) × (-0.0035)). When using the composition of eucalyptus fiber and fiber from MD Marathon received a significantly softer paper than in other cases. The composition of the fibers of the southern breeds of TD and MD is currently used for the manufacture of two-layer thin paper for retail sale. This composition is currently used in the development of prototypes of PM No. 2 single-layer toilet paper. Replacing the southern MD fiber with Marathon fiber, they slightly increase softness (see Table 1). Currently, a score of 16.9 points is the highest softness to touch achieved with SGRP equal to 450 (see Table 2). The average value over the entire work, where only the fiber of southern wood species was used, was 16.4 points. Achieving an estimate of softness to touch of 17.0 points with an SGRP of 450 is a significant technical problem. As a result of the creping process on the fabric according to the invention, a web with a very low modulus is obtained, suitable for retail or commercial paper. However, since the web is attached to the working body of the Yankee dryer by means of a fabric, there is a small contact area on the working body of the dryer. During the creping process in the Yankee dryer, there is less smoothing of the surface of the web compared to the usual attachment to the working body of the Yankee dryer by means of a fabric. The result is a flannel-like carcass compared to a silky carcass with conventional creping. The canvas from the side facing the surrounding atmosphere, as with conventional wet pressing, is less smooth than from the side facing the working body of the dryer. In a single-layer product, the side facing the surrounding atmosphere makes a certain contribution to the overall softness, since it cannot be hidden inside, as in a two-layer product. The result of this combination is a lower rating of softness to the touch. A modern approach to increasing softness is to increase the thickness with a relatively coarse creping fabric, add a softener and calendering with "high" pressure to iron the fabric and reduce two-sidedness. Composition for the manufacture of thin paper (commercial), for single-layer toilet paper, contains 40% fiber of the northern breeds of TD and 60% of secondary fiber. Table 3 presents the River River wet fiber sheet as a secondary fiber. The secondary fiber is a restored fiber of high whiteness. Only in a small number of points, a soft touch of 17.5 points is the best result at present. The average value is still 16.9 points. Here, the target soft touch score of 17.0 points is less problematic. All data in the tables below refer to the base fabric of a mixture of fibers. Fiber from TD and MD is usually prepared in separate pulp breakers and fed from various pulp tanks. Fiber is usually mixed with fan pumps, creating a homogeneous mixture of fibers.

Table 3 Composition Softness adjusted to SGPR = 450 80% Eucalyptus Fiber / 20% Marathon Fiber 17.6 80% TD southern fiber / 20% Marathon southern MD fiber 16.9 40% fiber of northern breeds TD / 60% of secondary fiber 16.8 100% recycled fiber 16,4 80% fiber of southern breeds TD / 20% fiber of southern breeds MD 16,4

Table 4 Composition The highest softness adjusted to SGPR = 450 80% Eucalyptus Fiber / 20% Marathon Fiber 18.3 40% fiber of northern breeds TD / 60% of secondary fiber 17.5 80% fiber of southern breeds TD / 20% fiber of southern breeds MD 16.9 80% TD southern fiber / 20% Marathon southern MD fiber 16.9 100% recycled fiber 16,4

Calendering with rubber and steel shafts

To reduce the two-sidedness of single-layer toilet paper, comparative calendering tests were carried out using a rubberized shaft and a conventional steel calender shaft from an ordinary pair of steel calender shafts. The rubberized shaft was installed on the side of the sheet facing the working body of the drying machine. Tables 5-7 below show the effect of calendering pressure on the thickness of the base web using rubberized rubber coated shafts of varying hardness. Using both rubberized shafts, the same levels of thickness reduction were achieved at equivalent pressures during calendering. Using a pair of steel shafts, significantly greater levels of thickness reduction were achieved at equivalent pressures during calendering, as shown in the table below. A shaft with a hardness of 56 according to Pusey and Jones (P + J), which is harder than a shaft with a hardness of (nominal) 80 by (P + J), should have provided a greater reduction in thickness at equivalent pressure. A shaft with a hardness (nominal) of 80 (P + J) was previously used in the work, and its actual hardness by measurements was 70 units of (P + J). The thickness of its coating was 5/8 inches, compared with a thickness of 1 inch of a shaft with a hardness of 56 (P + J). The calculated width of the zone of contact of the shaft with a hardness of 70 (P + J) with a coating thickness of 5/8 inches was slightly less than that of a shaft with a hardness of 56 (P + J) with a coating thickness of 1 inch. This explains the large degree of reduction in thickness that occurred when using the shaft “80 along (P + J)”.

Table 5 Calender type Calendering Pressure (psi) Thickness 8 layers of fabric (mil.) Thickness Reduction (%) Shaft with hardness 80 to (P + J) / Steel shaft 0 88.5 - Shaft with hardness 80 to (P + J) / Steel shaft 25 77.5 12,4 Shaft with hardness 80 to (P + J) / Steel shaft 55 71.1 19.7 Shaft with hardness 80 to (P + J) / Steel shaft 80 67.1 24.2 Shaft with hardness 80 to (P + J) / Steel shaft one hundred 64,4 27,2

* Base canvas density 21 lbs.

Table 6 Calender type Calendering Pressure (psi) Thickness 8 layers of fabric (mil.) Thickness Reduction (%) Hardness 56 (P + J) / Steel Shaft 0 89.4 - Hardness 56 (P + J) / Steel Shaft 25 80.0 11.7 Hardness 56 (P + J) / Steel Shaft fifty 75.7 15.4 Hardness 56 (P + J) / Steel Shaft fifty 75.9 15.1 Hardness 56 (P + J) / Steel Shaft 80 72,4 18.9 Hardness 56 (P + J) / Steel Shaft 80 73,2 18.1 Hardness 56 (P + J) / Steel Shaft one hundred 72.9 18,4 Hardness 56 (P + J) / Steel Shaft 200 65.9 26.3 Hardness 56 (P + J) / Steel Shaft 200 65.6 26.6

* Base canvas density 23 lbs.

Table 7 Calender type Calendering Pressure (psi) Thickness 8 layers of fabric (mil.) Thickness Reduction (%) Steel Shaft / Steel Shaft 0 86.1 - Steel Shaft / Steel Shaft 25 69,4 19.3 Steel Shaft / Steel Shaft 25 72.8 15.4 Steel Shaft / Steel Shaft fifty 61,4 28.7 Steel Shaft / Steel Shaft fifty 61.8 28,2 Steel Shaft / Steel Shaft 80 55.5 35.5 Steel Shaft / Steel Shaft one hundred 54.7 36,4 Steel Shaft / Steel Shaft 200 49.5 42,4

* Base canvas density 23 lbs.

With increasing pressure during calendering, double-sidedness is significantly reduced when using all types of calender rolls. However, webs subjected to calendering with rubber and steel shafts were not as soft to the touch as the base webs after calendaring with a pair of steel shafts. Figure 9 shows that at a given value of the GPR, the softness to the touch of the base webs is approximately 0.4 points higher after calendering a pair of steel shafts.

Some base sheets were calendared at various pressures using a pair of steel shafts. The calender is located before the roll of the paper machine. These base webs were then embossed during conversion to single layer toilet paper. The table below shows that calendering pressure had a small effect on the softness of the touch of fabrics containing high-quality fiber, i.e. fiber of eucalyptus TD and fiber Marathon MD. The softness of the canvases containing fiber from the northern breeds of the TD and the secondary fiber from Fox River increased at a pressure of 65 psi. inch when calendering, but decreased when the pressure on calendering was increased to 80 psi. inch. The softness of the southern fiber wood webs increased slightly with increasing pressure during calendaring. The use of variable processing conditions and various embossing patterns made it difficult to quantify the effect of calendaring on softness. However, it is obvious that some calendaring leads to an increase in softness, but too strong calendaring leads to a decrease in softness.

Softener Spray Comparison Tests

Comparative tests of Hercules D1152, TQ456 and TQ236 spray softeners were carried out, which were spray applied to the web side facing the surrounding atmosphere. The table below shows the test results. When adjusting to a preset value of the GPR, no differences in softness were observed when using softeners. Hercules M-5118 was also tested as a softening spray. This composition was a polypropylene glycol ether, as is known in the art. However, when it was sprayed onto the surface of the web facing the surrounding atmosphere at a rate of 2 lbs / t, when the web was on a drying cylinder with a diameter of 4 feet (transfer cylinder, FIG. 3), the web did not adhere to the creping fabric. When spraying was carried out on the surface of the fabric facing the working body of the dryer, or on the surface of the cloth in front of the suction rotary shaft (OPV), or on the surface of the creping fabric in front of the suction shaft (OPV) of the press, the fabric did not stick to the cylinder of the dryer 4 feet in diameter or to the working body of the Yankee dryer, respectively. When using other softeners, there was no problem sticking, and they did not adversely affect the coating of the Yankee dryer at a rate of 2 lb / t. However, at a flow rate of 4 lb / t or more, all formulations resulted in instability in the coatings of the Yankee dryer. The test results are presented in Table 8.

Table 8 Embossing pattern Calender Shafts Softener spray Softener Consumption, lb / t Softness to touch with SGPR = 450 According to US patent No. 6827819 Shaft with hardness 80 to (P + J) / Steel shaft TQ236 2 16.1 According to US patent No. 6827819 Shaft with hardness 80 to (P + J) / Steel shaft D1152 2 16.1 According to US patent No. 6827819 Hardness 56 (P + J) / Steel Shaft D1152 2 16,2 According to US patent No. 6827819 Hardness 56 (P + J) / Steel Shaft Tq456 2 16.1

Comparative tests to determine the effect of softener application at the wet end of the process

The addition of softeners at the wet end of the process to a dense pulp (usually to fiber TD) at a flow rate of up to 16 lb / t was possible without the instability of the Yankee dryer coating. The table below presents the results of comparative tests of the compositions Hercules TQ236, TQ456, D1152 and Clearwater CS359. All tests were performed under the same conditions. The pressure between the steel / steel calender shafts was 50 psi. inch. An embossing pattern according to US Pat. No. 6,827,819 was used for conversion. At equivalent costs and SGPR values, the effect of all softeners was the same. When the degree of refinement was increased to compensate for the increase in the amount of softener that acted as a baking powder, no increase in softness was observed. In this case, only the fiber of the southern breeds of MD was refined and the softener was added only to the fiber of the southern breeds of TD. These were tests aimed at testing the theory of using "a small number, but strong knots of fastening." By refining only MD to increase strength, it was theoretically possible to add more softener to TD fiber to increase softness. Refining only MD (20% of the composition of the canvas) did not result in a softer canvas. Although this was not confirmed by the Sensory Panel, the composition of D1152 was chosen as a softener mainly based on subjective assessments of softness. The results are shown in Table 9.

Table 9 Composition Refiner power, hp Calender Pressure, lb / n inch Softener introduced at the wet end of the process Softener Consumption, lb / t Softness to the touch, SGPR = 450 Fiber South TD / MD No load fifty TQ236 4.0 16.5 Fiber South TD / MD 46 fifty TQ236 8.0 16,4 Fiber South TD / MD 42 fifty Tq456 16,0 16.6 Fiber South TD / MD 43 fifty D1152 4,5 16,2 SHHW / MD 43 fifty D1152 7.5 16,4 Fiber South TD / MD 43 fifty D1152 9.0 16.8 Fiber South TD / MD No load fifty CS359 4.0 16.3 Fiber North Fiber / Secondary Fiber No load fifty D1152 8.0 16.8

The effect of embossed pattern

Various embossed patterns were used to determine whether a particular pattern interacts with a base fabric creped onto the fabric, causing an increase in softness. Recent studies have shown that a larger number of embossed patterns does not improve the softness of the base fabric, but leads to a decrease in strength. In more cases, the process conditions were the same, but not constant, for subsequent comparisons. However, they were similar enough to determine whether there was a significant increase in softness. The tables below show that one cannot account for any of the tested patterns a significant improvement in softness. Drawings “Two Hearts” “819” (according to US patent No. 6827819) and “Butterflies and whirlwinds”, obviously, gave the same softness to the touch. See Tables 10-13 below. It can be estimated that the “Mosaic Iris Flower” pattern gave a greater softness to the touch than the “Butterflies and Vortices with Micro” pattern. Based on these limited data, it is not recommended to use the “Butterflies and Vortices with Micro” pattern for the base fabric creped onto the fabric. The embossed patterns “M3” and “Mosaic iris flower” give the same softness, and should be considered equivalent to those presented in Table 10 with constant compositions and SGR values.

Table 10
Fiber of southern breeds TD / fiber of southern breeds MD Embossed drawing SGPR Soft touch Softness at SGPR = 450 "Two hearts" 493 16,4 16.6 According to US patent No. 6827819 399 16.6 16,4 "Butterflies and whirlwinds" 454 16.3 16.3 "Butterflies and whirlwinds" 421 16,4 16.3 According to US patent No. 6827819 417 16,4 16.3 According to US patent No. 6827819 420 16.3 16,2 According to US patent No. 6827819 403 16.3 16.1

Table 11
40% Fiber of Northern Fibers TD / 60% Secondary Fiber (WB) of Fox River Embossed drawing SGPR Soft touch Softness at SGPR = 450 "Mosaic flower iris" 439 17.5 17.5 “Butterflies and whirlwinds, micro” 376 17.3 17.0

Table 12
40% TD Eucalyptus Fiber / 60% Secondary Fiber (WB) from Fox River Example Embossed drawing SGPR Soft touch Softness at SGPR = 450 255 "Mosaic flower iris" 477 17.6 17.7 254 “Butterflies and whirlwinds, micro” 451 17.0 17.0 256 “Butterflies and whirlwinds, micro” 419 17.0 16.9

Table 13
Fiber of eucalyptus rocks TD / fiber Marathon MD Example Embossed drawing SGPR Soft touch Softness at SGPR = 450 271 MH 428 18.6 18.5 271 MH 584 17.8 18.3 257 "Mosaic flower iris" 507 18.1 18.3 259 “Butterflies and whirlwinds, micro” 478 17.9 18.0 258 “Butterflies and whirlwinds, micro” 454 18.0 18.0

The relationship between the degree of creping on the fabric and

degree of creping on the coast

The base fabric was made with a constant degree of creping on the entire line, but with a wide range of creping degrees on the fabric. Full-line creping, or total creping, is calculated by dividing the velocity of the transfer cylinder (which is also approximately the molding speed) by the roll speed. Subtract 1 from this value. The resulting value is multiplied by 100 and the result, expressed as a percentage, is obtained. To determine the degree of creping on the fabric, the speed of the transfer cylinder is divided by the speed of the working body of the Yankee dryer, since this speed is also the speed of the creping fabric, and then subtract 1 and the resulting value is multiplied by 100. To determine the degree of creping on the coast, the speed of the worker the organ of the Yankee dryer is divided by the roll-up speed and then subtract 1 and the resulting value is multiplied by 100. In general, the speed of the transfer cylinder and the roll-up speed were kept constant, and the speed of the working body and the Yankee dryer was varied to obtain different ratios of degrees of creping on the fabric and on the coast. Test data of the base web show that the highest elongation in the longitudinal direction occurred at the highest degree of creping on the coast. The lowest value of the geometric mean (GS) values of the modulus of rupture and the highest value of elongation in the transverse direction occurred at the highest degree of creping on the fabric. We did not observe problems with processing on the line with any of the canvases. Variable process parameters, with the exception of the speed of the Yankee dryer and the addition of coating to the Yankee dryer, the amount of which was increased in Example 56, were kept constant. In terms of physical properties, the canvases were substantially similar in the limiting range of the implemented ratios of the degrees of creping on the fabric and on the roll. The results are summarized in Table 14. In these tests, the transfer cylinder was a drying cylinder with a diameter of 4 feet.

Table 14 Base canvas Example 56 54 55 57 4-foot diameter drying cylinder speed 2401 2403 2400 2399 Yankee Dryer Speed 2200 1800 1530 1400 Reel speed 1423 1402 1399 1400 The degree of creping on the fabric,% 9 34 57 71 The degree of creping on the coast,% 55 28 9 0 The degree of creping on the line,% 69 71 72 71 Density 24.2 23.3 24.5 24.0 8 layer thickness 72.6 73,4 74.0 70.9 Longitudinal tensile strength 569 510 545 499 Elongation in the longitudinal direction 68,4 59.3 62.3 59.7 Transverse tensile strength 676 617 682 610 Elongation in the transverse direction 6.4 6.0 6.8 8.4 Geometric Mean Tensile Strength 620 561 608 552 The ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction 0.84 0.83 0.80 0.82 The geometric mean value of the modulus of the gap 29th thirty 29th 25 Longitudinal rupture module 8 9 9 8 Transverse Rupture Module 101 103 99 73

All of the canvases were processed into rolls of finished single-layer toilet paper, in which either there was no embossed design, or the design was as described in US Patent No. 6827819. The physical characteristics shown in Tables 15 and 16 below were very similar to those of the base fabric given above. Cloths creped only on fabric and not creped on the roll (Example 57) had a significantly greater elongation in the transverse direction and a smaller tensile modulus in the transverse direction. The geometric mean value of the fracture modulus was directionally smaller. However, estimates of softness to the touch did not indicate an improvement in the softness of any of the paintings.

Table 15 Converted, embossed design according to US patent No. 6827819 Example 212 208 210 214 The degree of creping on the fabric,% 9 34 57 71 The degree of creping on the coast,% 55 28 9 0 The degree of creping on the line,% 69 71 72 71 Soft touch 16,2 16.1 15.9 16,2 Density 20.7 20.7 22.1 21.7 8 layer thickness 75.8 73.7 76,4 72.9 Longitudinal tensile strength 505 457 498 444 Elongation in the longitudinal direction 36.8 37.7 40,0 38.6 Transverse tensile strength 447 446 514 427 Elongation in the transverse direction 6.8 6.7 6.7 7.8 Geometric Mean Tensile Strength 475 451 506 435 The ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction 1.13 1,03 0.97 1,04 The geometric mean value of the modulus of the gap 30.1 28.5 30.9 25.1 Longitudinal rupture module 13.7 12.1 12.5 11.5 Transverse Rupture Module 66.1 67.1 76.5 54.9

Table 16 No embossing Example 211 207 210 213 The degree of creping on the fabric,% 9 34 57 71 The degree of creping on the coast,% 55 28 9 0 The degree of creping on the line,% 69 71 72 71 Soft touch 15.4 15.8 15,2 15.7 Density 22.6 22.6 23,4 24.2 8 layer thickness 70.1 68.7 67.3 67.0 Longitudinal tensile strength 567 493 496 536 Elongation in the longitudinal direction 50.8 46.6 45.4 47.5 Transverse tensile strength 561 559 628 583 Elongation in the transverse direction 5,0 5.5 6.0 6.9 Geometric Mean Tensile Strength 564 525 558 559 The ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction 1.01 0.88 0.79 0.92 The geometric mean value of the modulus of the gap 35.3 32.8 33.8 30.9 Longitudinal rupture module 11.1 10.6 10.9 11.3 Transverse Rupture Module 111.9 101.7 104.9 84,4

The effect of creping tissue

Crepe fabrics of various structures were used to make base linens for conversion to single layer toilet paper. Table 17 below shows the performance of the base paintings obtained under the same process conditions. The line “Type of creping fabric” indicates the density of monofilament warp and weft, for example 42x31. First, the density on the basis (the density of longitudinal threads) is indicated. The abbreviations MD (PrN) and CD (PN) indicate the longest bend on the side of the fabric facing the canvas. The letters M, G, and B denote types of weave. The largest thickness, without calendaring, was achieved using fabric with a density of 56x25. This made it possible to produce stronger calendering, which nevertheless produced a roll of the desired diameter and density of the processed product. Higher calendering levels were supposed to reduce two-sidedness and could lead to increased softness.

Table 17 Base canvas Type of creping fabric 44G, CD (42X31) 56X45M, MD 56X25G, MD 56X25G, CD 36X32B, MD 56X25M, CD Density (no calendering) 23.9 24.2 23.8 24.5 24.2 --- Thickness of 8 layers of a cloth (without calendering) 87 91 102 103 98 --- Calender Pressure, lb / n inch twenty fifty 80 80 fifty fifty Density (after calendering) 23,2 24.0 23.0 23.7 23.0 21.3 Thickness 8 layers of fabric (after calendering) 78.7 63.9 63.9 67.6 68.1 63.6

When converted using a pattern according to US Pat. No. 6,827,819, using 56x25G fabric and at a pressure in calenders of 80 psi. inch received canvas with directionally higher softness to the touch.

The influence of the ratio of tensile strength in the longitudinal and transverse directions

Using the creping process on the fabric, it is possible to easily adjust the ratio of tensile strengths in the longitudinal and transverse directions to a wider range than with conventional wet pressing and drying with air suction (SPV). The ratios 4.0–0.4 were achieved without approaching the process parameters to their limiting values. It is usually required that the tensile strength of the thin paper in the longitudinal direction is higher than in the transverse direction to maximize the forming process. To ensure maximum softness, tensile strength in the transverse direction was kept as low as possible. This has led to an increased risk of damage when used by consumers. If it was possible to increase the tensile strength in the transverse direction, and reduce the tensile strength in the longitudinal direction, then the SGR would remain constant. Thus, with equivalent total strength, the possibility of damage is less. The table below shows the performance of a single-layer finished toilet paper obtained in two separate tests, in which the ratio of tensile strengths in the longitudinal and transverse directions was varied. The performance of comparative examples 90, 89, 107 and 108 are shown in Table 18. With a decrease in the ratio of tensile strengths in the longitudinal and transverse directions, the modulus in the transverse direction and the geometric mean of the modulus increased. However, this did not have a significant effect on softness to the touch when they took into account SGPR. Strength in the transverse direction was increased by approximately 100 g per strip of width 3 inches. This should have led to a significant reduction in the risk of damage during use. The extensibility of the base web could help prevent tearing due to low strength. For high-speed commercial operations, it may be necessary to modify the perforating blade to accommodate low strength and high elongation.

Table 18 Composition 80% Eucalyptus Fiber / 20% Marathon Fiber 80% Eucalyptus Fiber / 20% Marathon Fiber 70% of northern breeds of AN TD / 30% of northern breeds of AN MD 70% of northern breeds of AN TD / 30% of northern breeds of AN MD Example 90 89 107 108 The ratio of tensile strength in the longitudinal and transverse directions 1.78 1.18 1.37 0.91 Soft touch 18.2 17.7 16.3 16,4 Softness at SGPR = 450 17.9 17.6 16.1 16.3 SGPR 371 427 403 417 Density 20.3 20,2 20.3 20,4 Thickness 63.3 65.9 67.0 67.8 Longitudinal tensile strength 494 463 471 397 Transverse tensile strength 278 393 345 438 Elongation in the longitudinal direction 25.0 24.4 37.6 34.1 Elongation in the transverse direction 7.8 5.9 8.7 7.1 Longitudinal rupture module 19.8 19.0 12.6 11.7 Transverse Rupture Module 35.9 67.0 39.8 61.1 Geometric Mean Tensile Strength 26.6 35.7 22.4 26.7

The effect of fiber content of southern rocks TD

The effect of the fiber content of southern TD species on softness to the touch is shown in Table 19. No increase in softness when the fiber content of TD was about 75% was observed. In both cases, the softness was noticeably lower than the target value of 17.0 points. Calendering was carried out with a rubberized shaft with a hardness of 80 (P + J) paired with a steel shaft.

Table 19 Example Embossed drawing Fiber of southern breeds TD Softness to touch with SGPR = 450 196 According to US patent No. 6827819 75 16,2 200 According to US patent No. 6827819 fifty 16.1

Effect of softener spray on degree

creping on fabric

Variable process parameters were changed to determine factors, if they exist, that would contribute to obtaining the finished product with a soft touch of 17.0 points using fiber from the southern breeds of TD and MD. In one such comparative test, a base web without a sprayed softener was used with a high degree of creping on the fabric to control strength and a low degree of creping on the fabric using spraying the softener to adjust the strength. Table 20 shows that the softness was the same when adjusting to a specific value of the GPR. In both cases, the softness was noticeably lower than the target value of 17.0 points. Calendering was carried out with a rubberized shaft with a hardness of 80 (P + J) paired with a steel shaft.

Table 20 Prototype single layer toilet paper PM No. 2, roll No. Embossed drawing Softener spray consumption, lb / t The degree of creping on the fabric,% Softness to touch with SGPR = 450 200 According to US patent No. 6827819 2 31 16.1 198 According to US patent No. 6827819 0 56 16.1

The effect of vacuum in the forming box

The forming box was located on the creping fabric between the creping shaft and the rigid press shaft. The solids content in the canvas was usually in the range of 38-44% at this point. The effect of rarefaction on the thickness of the web is shown in the table. An increase of almost 8 mils in the thickness of the 8-layer web was observed with a rarefaction of 21 inches of mercury in the forming box. This increase was about 14%. Both rolls were calendared with a pair of steel shafts at a pressure of 50 psi. inch. The increase in thickness depended on the density of the weave of the fabric and on the degree of vacuum created. This did not have a significant effect on other properties of the canvas. The use of the forming box influenced the drying process. In the absence of a significant change in temperature in the chamber of the Yankee dryer, the web moisture content after the Yankee dryer increased by 2.66-3.65%. Under the action of rarefaction, the web was embedded more deeply into the creping fabric and thus there was less contact with the working body of the Yankee dryer and a greater degree of drying was required to maintain the web moisture. See Table 21. In this case, the temperature in the chamber of the Yankee dryer was not controlled.

Table 21 Crepe fabric Depression in the molding box, inch of mercury Thickness 8 layers of canvas, mil The moisture content of the web, determined by the scanning device,% 44g 0 56.7 2.66 44g 21 64.6 3.65

The effect of moisture on the creping fabric

on the properties of the base canvas

By changing the process variables, the moisture of the web entering the process zone occupied by the creping fabric can be changed. On a used paper machine equipped with a 120 mm shoe press, with a web density of 22 pounds, the solids content can be varied within the range of about 33-46%. At a low solids content, the vacuum in the suction rotary shaft (OPV) was reduced, the pressure of the press shoe was reduced, and the steam temperature in the drying cylinder with a diameter of 4 feet was reduced. To dry this canvas to a moisture content of about 2% on the coast, the steam temperature and the temperature in the chamber of the Yankee dryer had to be increased. The low solids base web had an SPS value of approximately 270 g / 3 in. less than the SGPR value of the base web with a high solids content. See the table below. This was mainly due to the smaller compaction that took place with less pressure on the press shoe. When creping on fabrics, fiber redistribution occurs to a large extent, but, obviously, it is impossible to completely rebuild the compaction achieved by pressing. Other physical properties, including absorption capacity (water) (SAT), did not differ significantly, taking into account differences in strength. This experiment should be repeated under constant pressing conditions by using only vacuum and steam to alter the solids content of the web. However, based on this experiment, it is assumed that one should not expect a significant effect of the solids content in the web on the properties of the base web within the conditions accepted in this work. The impact during drying is significant, and attention should be paid to the fact that it would be advisable to expand the limits of the solids content for research. The results are summarized in Table 22.

Table 22 Crepe on fabrics with a “low” solid content Crepe on fabrics with a “high” solids content Example 94 95 Solid content before creping on fabric 33.8 46.1 Temperature in the chamber of the Yankee dryer 950 550 Pressure in a Yankee tumble dryer, psi inch 110 105 Vacuum in the suction rotary shaft 7.9 13.1 Press shoe pressure, lb / p. inch 200 500 <Parameter> steam in a drying cylinder with a diameter of 4 feet 25 70 Density 22.3 22.8 Thickness 91.2 85,2 Longitudinal tensile strength 976 1236 Elongation in the longitudinal direction 52,2 53.7 Transverse tensile strength 1205 1481 Elongation in the transverse direction 5.8 5,6 Geometric Mean Tensile Strength (GPR) 1084 1353 The ratio of tensile strength in the longitudinal direction to tensile strength in the transverse direction 0.81 0.83 The geometric mean value of the modulus of the gap 61 78 Transverse Rupture Module 205 261 Longitudinal rupture module eighteen 24 Absorption Capacity (Water) (SAT) 190 168

Although the invention has been described with reference to some examples, the ability to modify these examples within the spirit and scope of the invention is readily apparent to those skilled in the art. Taking into account the above, the essential knowledge accumulated in this field, links, including links to applications that are simultaneously under consideration, as discussed above in the section relating to analogues and in the section "Detailed description of the invention", the essence of which is incorporated into this application by links, it is assumed that there is no need for a more detailed description.

Claims (33)

1. An absorbent cellulosic fiber web containing a mixture of hardwood and softwood fibers arranged in a mesh structure comprising (i) a plurality of columnar clusters of fibers with a relatively high local density interconnected by (ii) a plurality of connecting regions with a lower local density, in which the orientation of the fibers is inclined along the direction between the columnar regions interconnected in such a way that the relative density, the degree of columnar ty, the ratio of hardwood to softwood, fiber length distribution, fiber orientation and mesh geometry are controlled so that the web has a relative elongation in the transverse direction, which is at least about 2.75 times greater than the relative strength when stretching the web in a dry state. 2. The absorbent cellulosic fabric according to claim 1, having a porosity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 5%, and a ratio of tensile strength in the longitudinal direction to tensile strength in a transverse direction of less than about 1.75. 3. The absorbent cellulosic fabric according to claim 1, having a porosity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 5%, and a ratio of tensile strength in the longitudinal direction to tensile strength in a transverse direction of less than about 1.5. 4. The absorbent cellulosic fabric according to claim 1, having a porosity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 10%, and a ratio of tensile strength in the longitudinal direction to tensile strength in a transverse direction of less than about 2.5. 5. The absorbent cellulosic fabric according to claim 1, having a porosity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 15%, and a ratio of tensile strength in the longitudinal direction to tensile strength in a transverse direction of less than about 3.5. 6. The absorbent cellulosic fabric according to claim 1, having an absorption capacity of at least about 5 g / g, a relative elongation in the transverse direction of at least about 20%, and a ratio of tensile strength in the longitudinal direction to tensile strength in a transverse direction of less than about 5. 7. The absorbent cellulosic fabric according to claim 1, having a relative elongation in the transverse direction, which is at least about 3 times greater than the relative tensile strength of the fabric in the dry state. 8. The absorbent cellulosic fabric according to claim 1, having a relative elongation in the transverse direction, which is at least approximately 3.25 times greater than the relative tensile strength of the fabric in the dry state. 9. The absorbent cellulosic fabric according to claim 1, having a relative elongation in the transverse direction, which is at least about 3.5 times greater than the relative tensile strength of the fabric in the dry state. 10. The absorbent cellulosic fabric according to claim 1, having a relative elongation in the transverse direction of at least about 4%, and a relative tensile strength of the fabric in the dry state, comprising from about 0.4 to about 4.0. 11. The absorbent cellulosic fabric of claim 10, having an elongation in the transverse direction of at least about 5%. 12. The absorbent cellulosic fabric of claim 10, having an elongation in the transverse direction of at least about 6%. 13. The absorbent cellulosic fabric of claim 10, having an elongation in the transverse direction of at least about 8%. 14. The absorbent cellulosic fabric of claim 10, having an elongation in the transverse direction of at least about 10%. 15. The absorbent fabric according to claim 1, having a porosity of at least 6 g / g. 16. The absorbent fabric according to claim 1, having a porosity of at least 7 g / g. 17. The absorbent fabric according to claim 1, having a porosity of at least 8 g / g. 18. The absorbent fabric according to claim 1, having a porosity of at least 9 g / g. 19. The absorbent fabric according to claim 1, having a porosity of at least 10 g / g. 20. The absorbent fabric according to claim 1, consisting mainly of fiber from hardwood. 21. The absorbent fabric according to claim 1, consisting mainly of softwood fiber. 22. A method of manufacturing a cellulosic fibrous layer for the production of tissue paper, including
(a) preparing an aqueous cellulosic composition for the manufacture of paper, consisting mainly of hardwood fibers;
(b) feeding the paper composition to the forming fabric as a stream discharged from the headbox at a flow rate;
(c) compaction dewatering of a paper making composition for forming a starting fibrous layer having an apparent random distribution of papermaking fiber;
(d) laying the dehydrated fibrous layer having an apparent random distribution of the fiber on a conveying transmission surface moving at a first speed;
(e) creping on a tape of the fibrous layer from the transfer surface with a dryness of from about 30% to about 60% using a patterned creping tape; moreover, the creping stage is performed under pressure in the contact zone of the creping tape, limited between the transmitting surface and the creping tape, where the tape is moved at a second speed less than the speed of the transmitting surface; moreover, the pattern of the tape, the parameters of the contact zone, the speed difference and the dryness of the fibrous layer are selected so as to crepe the fibrous layer when removed from the transmitting surface and redistribute on the creping tape with the formation of a fibrous layer with a mesh structure containing many interconnected areas with different local density, including at least (i) a plurality of clusters of fibers having a high local density interconnected by (ii) a plurality of connecting regions, o having a lower local density;
(f) drying the fibrous layer; and
(g) adjusting the ratio of the fiber content of hardwood to softwood, the distribution of fiber lengths, the total degree of creping, the flow rate, the drying and creping stages on the tape, and also selecting the pattern of the creping tape so that the fiber layer is different in that it has elongation in the transverse direction, which is at least about 2.75 times greater than the relative tensile strength of the fibrous layer in the dry state. 23. The method of claim 22, further comprising the step of calendering the fiber layer between the first steel calender shaft and the second steel calender shaft. 24. A method of manufacturing a cellulosic fibrous layer for the manufacture of products in the form of towels, including
(a) preparing an aqueous cellulosic composition for the manufacture of paper, consisting mainly of softwood fiber;
(b) feeding the paper composition to the forming fabric as a stream discharged from the headbox at a flow rate;
(c) compaction dewatering of a paper making composition for forming a starting fibrous layer having an apparent random distribution of papermaking fiber;
(d) laying the dehydrated fibrous layer having an apparent random distribution of the fiber on a conveying transmission surface moving at a first speed;
(e) creping on a tape of the fibrous layer from the transfer surface with a dryness of from about 30% to about 60% using a patterned creping tape; moreover, the creping stage is performed under pressure in the contact zone of the creping tape, limited between the transmitting surface and the creping tape, where the tape is moved at a second speed less than the speed of the transmitting surface; moreover, the pattern of the tape, the parameters of the contact zone, the speed difference and the dryness of the fibrous layer are selected so as to crepe the fibrous layer when removed from the transmitting surface and redistribute on the creping tape with the formation of a fibrous layer with a mesh structure containing many interconnected areas with different local density, including at least (i) a plurality of clusters of fibers having a high local density interconnected by (ii) a plurality of connecting regions, o having a lower local density;
(f) drying the fibrous layer; and
(g) adjusting the ratio of the fiber content of hardwood to softwood, distribution of fiber length, total creping, flow rate, drying and creping stages on the tape, as well as selecting a pattern for the creping tape so that the fiber layer is different in that it has elongation in the transverse direction, which is at least about 2.75 times greater than the relative tensile strength of the fibrous layer in the dry state. 25. A method of manufacturing a creped on a tape absorbent cellulosic fabric, comprising
(a) preparing a cellulosic composition comprising a mixture of hardwood and softwood fibers;
(b) feeding the paper composition to the forming fabric as a stream discharged from the headbox at a flow rate;
(c) compaction dewatering of a paper making composition for forming a starting fibrous layer having an apparent random distribution of papermaking fiber;
(d) laying the dehydrated fibrous layer having an apparent random distribution of the fiber on a conveying transmission surface moving at a first speed;
(e) creping on a tape of the fibrous layer from the transfer surface with a dryness of from about 30% to about 60% using a patterned creping tape; moreover, the creping stage is performed under pressure in the contact zone of the creping tape, limited between the transmitting surface and the creping tape, where the tape is moved at a second speed less than the speed of the transmitting surface; moreover, the pattern of the tape, the parameters of the contact zone, the speed difference and the dryness of the fibrous layer are selected so as to crepe the fibrous layer when removed from the transmitting surface and redistribute on the creping tape with the formation of a fibrous layer with a mesh structure containing many interconnected areas with different local density, including at least (i) a plurality of clusters of fibers having a high local density, interconnected by (and) a plurality of connecting regions, o having a lower local density;
(f) drying the fibrous layer; and
(g) adjusting the ratio of the fiber content of hardwood to softwood, the distribution of fiber lengths, the total degree of creping, the flow rate, the drying and creping stages on the tape, and also selecting the pattern of the creping tape so that the fiber layer is different in that it has elongation in the transverse direction, which is at least about 2.75 times greater than the relative tensile strength of the fibrous layer in the dry state. 26. The method according A.25, in which the orientation of the fibers in the areas of accumulation of fibers is inclined in the transverse direction. 27. The method according A.25, performed when the degree of creping on the fabric in the range from about 10% to about 100%. 28. The method according A.25, performed when the degree of crepe on the fabric, comprising at least about 40%. 29. The method according A.25, performed when the degree of crepe on the fabric, comprising at least about 60%. 30. The method according A.25, performed when the degree of crepe on the fabric, comprising at least about 80%. 31. The method according A.25, performed when the degree of crepe on the fabric component of 100% or more. 32. The method according A.25, performed when the degree of crepe on the fabric, comprising about 125% or more. 33. The method according A.25, in which the fibrous layer contains a secondary fiber.

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