MXPA02005170A - Thick and smooth multi ply tissue. - Google Patents

Abstract

The present invention relates to a paper tissue, and in particular to facial tissue, and disposable handkerchiefs. Claimed and described is a paper tissue comprising at least two plies, characterised in that the paper tissue has a physiological surface smoothness parameter of less than 700 microns, preferably from 650 microns to 50 microns, more preferably from 650 microns to 300 microns and in combination has a caliper per ply of more than 0.09 mm, preferably from 0.09 mm to 0.5 mm, more preferably from 0.1 mm to 0.2 mm. In one preferred embodiment a three ply tissue with embossed middle ply is provided. Further is a related process claimed and described.

Description

PAPER TISU OF MULTIPLE LEAVES THICK AND SMOOTH FIELD DK THE INVENTION The present invention relates to tissue paper, and in particular to facial tissues and disposable handkerchiefs. In a preferred embodiment, a three-ply tissue with a recorded intermediate sheet is provided.

BACKGROUND OF THE INVENTION Paper webs or sheets, sometimes referred to as tissue or tissue paper webs, or herein referred to as tissue paper, find extensive use in modern society. These items, such as facial tissue and toilet paper, are important trade items, all referred to herein as tissue paper. To a large extent it has been recognized that the important physical attributes of these products are their strength and thickness / caliber, their smoothness and smoothness, their absorbency, and their resistance to loose lint. The research and development efforts have been directed to the improvement of each of these attributes without seriously affecting the others as well as the improvement of two or three attributes simultaneously.

Smoothness and smoothness are related to the sensation of the consumer's perceived touch when holding a particular product, rubbing it through the skin, or squeezing it inside the hands. This touch sensation is a combination of different physical properties. It is considered by those skilled in the art that one of the most important physical properties related to smoothness and smoothness in general is the surface structure of the tissue paper from which the tissue product is made and is the one that best captures the parameter of physiological surface smoothness (PSS), as is known, for example, from US 5,855,738. Equally important for the feel of consumers is the thickness / caliber of a tissue product. Resistance is the ability of the product to maintain physical integrity and to resist tearing, breaking and shredding under conditions of use. Absorbency is the measurement of the capacity of a product to absorb quantities of liquid, in particular aqueous solutions or dispersions. In general, it is considered that the total absorbency as perceived by the consumer is a combination of the total amount of a liquid that a given mass of tissue will absorb in saturation as well as the speed at which the mass absorbs the liquid. Lint release resistance is the ability of the fibrous product, and its constituent webs, to coalesce together under conditions of use, even when wetted. In other words, the greater the resistance to loose fluff, the lower the predisposition of the weft to loosen fluff. W097 / 44528 discloses a multi-sheet tissue product with high absorbency. Example 4 discloses a product wherein a relatively textured and patterned sheet is placed between two relatively untextured sheets, substantially without pattern. EP 0 264 676 discloses a process for the production of sheets of paper with multiple sheets. Example 3 discloses a three-ply product made from wet-formed paper, where the internal web is provided from etched paper with a weight of 18 g / m 2 and the external plies are provided from calendered paper with a weight of 14g / m2. The sheets are assembled by an adhesive with cellulose ether applied by means of nozzles. US 5,855,738 discloses a process for making smooth tissue paper comprising a calendering step. Relatively thick disposable paper products are known, namely in the form of paper handkerchiefs and facial tissues. For example, TempoMR, sold by The Procter & Gamble Company, has a caliber of between approximately 0.3 mm. A larger caliber conveys the idea to the consumer of superior drying and wet strength. A high wet strength, also referred to as resistance to gusts of moisture, in particular prevents tearing or breaking which in turn results in contamination of the user's hand with mucus or other body fluids. Even thicker, disposable paper products are known, and are typically used as kitchen towels, such as, for example, Bounty ™, sold by The Procter & amp;; Gamble Company, which has a caliber of between about 0.7 mm and a resistance to gusts of humidity that is greater than 200 g. However, these kitchen towels should adjust to a considerable degree its caliber for "engraving on the total surface which results in a surface texture that is rough and does not provide a properly smooth cleaning surface for nose blowing." Other products with high resistance to moisture bursts and typically a relatively larger caliber are those produced by air-pass drying, however air-drying facilities are not available in conventional paper machines and - the provision of this equipment means a considerable financial investment. In theory, the wet strength and caliber of a product can be increased by increasing the number of sheets to 5, 6 or even more (instead of engraving or the like) and thereby maintaining a smooth external surface. The proposal could be very expensive and also lead to a rigid product, thus compromising the perception of the touch. By providing a very smooth surface it is common in the art to subject the tissue paper to calendering. However, calendering always means an exchange of caliber and softness smoothness (as' is discussed for example in US 5, 855, 738). In view of the prior art there remains a need for a tissue product, in particular a facial tissue, which: combines optimum strength, namely resistance to moisture bursts, absorbency and lint-freeing resistance - additionally provides a feeling to the ideal touch of softness, smoothness and thickness - be of profitable cost for manufacturing and preferably that can be manufactured in conventional paper machines - optionally provide benefits for skin care BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a tissue paper, and in particular to facial tissues, and disposable handkerchiefs. A tissue paper comprising at least two sheets is characterized and claimed, characterized in that the tissue paper has a parameter of physiological surface smoothness of less than 700 microns, preferably between 650 microns and 50 microns, more preferably between 650 microns and 300 microns and in combination has a caliber per sheet 'greater than 0.09 mm, preferably between 0.09 mm and 0.5 mm, more preferably between 0.1 mm and 0.2 mm. In a preferred embodiment, a three-ply tissue paper with a recorded intermediate sheet is provided. In addition, a related process is claimed and described.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a cellulosic fibrous structure is that of wet laying using the principles and machinery well known in the papermaking art.A pulp pulp suitable for the process of the tissue paper substrate preferably contains paper fibers consisting essentially of cellulose fibers (commonly known as wood pulp fibers) or fibers derived from cellulose (including, for example, rayon, viscose) fibers derived from soft woods (gymnosperms or conifers) and hardwoods (angiosperms or deciduous) are contemplated for use in this invention.The particular species of the tree from which the fibers are derived is not important.The fibers of wood pulp They can be produced from natural wood by any process for convenient pulp production. Chemical processes such as, for example, sulfite, sulphate (including Kraft) and processes with soda are suitable. Mechanical processes such as, for example, thermochemical processes (or Asplund) are also suitable. In addition, the various i-chemical and chemical-mechanical processes can be used. Bleached as well as unbleached fibers are contemplated for use. Preferably, fibers without cellulose, such as for example latex fibers, are not used. The tissue paper according to the present invention may contain, as a very preferred component a chemical agent resistant to moisture. Preferably they are contained up to about 3.0%, preferably at least 0.5%, and most preferably at least 0.8% by weight, on a dry fiber weight basis of the moisture resistant chemical agent, such as, for example, water-resistant resin. permanent and temporary moisture soluble in water. The moisture resistant resins useful herein can be of various types. For example, Westfelt describes several of these materials and analyzes its chemistry in De Cellulose Chemistry and Technology, Volume 13, on pages 813-825 (1979). In general, moisture-resistant resins are water-soluble cationic materials. That is, the resins are soluble in water at the time they are added to the pulp. It is quite possible, and even expected, that subsequent events such as, for example, crosslinking will make the resins insoluble in water. In addition some resins are soluble only under specific conditions, such as, for example, over a limited variation in pH. It is generally believed that the moisture resistant resins undergo cross-linking or other curing reactions after they have been deposited on, in, or between the paper fibers. Cross-linking or curing usually does not occur unless substantial amounts of water are present. Of particular utility are the various polyamide-epichlorohydrin resins. These materials are low molecular weight polymers provided with reactive functional groups such as, for example, amino, epoxy, and azetidinium groups. The Patent literature is replete with descriptions of processes for making these materials, including US-A-3 700 623, issued to Keim on October 24, 1972, and US-A-3 772 076, issued to Keim on December 13, 1972; November 1973. The polyamide-epihydrochlorin resins sold under the trademarks Kymene 557H and Kymene LX by Hercules Inc. of Wilmington, Delaware, in particular, are useful in this invention. These resins are generally described in the aforementioned Keim patents. The polyamide-epichlorohydrin resins activated with bases useful in the present invention are sold under the trademark Santo Res, such as, for example, Santo Re 31, by Monsanto Company of St. Louis, Missouri. These types of materials are generally described in US-A-3 855 158 issued to Petrovich on December 17, 1974; US-A-3 899 388 issued to Petrovich on August 12, 1975; US-A-4 129 528 issued to Petrovich on December 12, 1978; US-A-4 147 586 issued to Petrovich on April 3, 1979; and US-A-4 222 921 issued to Van Eenam on September 16, 1980. Other water-soluble cationic resins useful herein are the resins of polyacrylamide such as, for example, those sold under the trademark Parez, such as, for example, Parez 631 NC, by American Cyanamid Company of Sandford, Connecticut. These materials are generally described in US-A-3 556 932 issued to Coscia et al on January 19, 1971; and US-A3 556 933 issued to Williams et al, on January 19, 1971. Other types of water-soluble resins useful in the present invention include acrylic emulsions and anionic styrene-butadiene latexes. Many examples of these types of resins are provided in US-A-844 880. Meisel Jr et al, issued October 29, 1974. Still other water-soluble cationic resins which find utility in this invention are urea formaldehyde resins and melamine formaldehyde. These reactive, polyfunctional polymers have molecular weights in the order of a few thousand. The most common functional groups include nitrogen-containing groups such as, for example, amino groups and methylol groups attached to the nitrogen atom. Although less preferred, polyethylene imine type resins find utility in the present invention.

More complete descriptions of the water-soluble resins mentioned above, including their manufacture, can be found in TAPPI Monograph Series No. 29, "Wet Strength in Paper and Paperboard, Technical Association of the Pulp and Paper Industry (New York, 1965) Temporary agents for wet strength, such as for example modified starch, may also be optionally used Combinations of permanent and temporary agents for wet strength may be used The present invention may contain chemical agents for dry strength, preferably at levels of up to 3% by weight, more preferably at least 0.1% by weight, on a dry fiber weight basis. A most preferred dry strength chemical agent is carboxymethylcellulose. Other suitable chemical dry strength agents include polyacrylamide (such as, for example, combinations of CyproMR 514 and Accos trength ™ 711 produced by American Cyanamid of Wayne, N.J.); starch (such as, for example, corn starch or potato starch); polyvinyl alcohol (such as, for example, AirvolMR 540 produced by Air Products Inc. of Allentown, PA); guar or carob gums; and latex polyacrylate. Suitable starch materials can also include modified cationic starches such as, for example, those modified to have nitrogen-containing groups such as, for example, amino groups and methylol groups attached to nitrogen, available from National Starch and Chemical Company (Bridgewater, NJ) . Chemical softening compositions, comprising chemical disintegrating agents are optional components of the present invention. US-A-3 821 068, issued June 28, 1974, teaches that chemical disintegrating agents can be used to reduce stiffness, and thus intensify the softness of a tissue paper web. US-A-3 554 862, issued on January 12, 1971 discloses suitable chemical disintegrating agents. These chemical disintegrating agents include quaternary ammonium salts. Preferred chemical softening compositions comprise between about 0.01% and 3.0% of a quaternary ammonium compound, preferably a biodegradable quaternary ammonium compound; and between about 0.01% and 3.0% of a polyhydroxy compound; preferably selected from the group consisting of glycerol, sorbitols, polyglycerols having an average molecular weight of between about 150 and 800 and polyoxyethylene glycols and polyoxypropylene glycols having an average molecular weight of between about 200 and 4000. Preferably the weight ratio of the quaternary ammonium compound to the polyhydroxy compound varies from between approximately 1.0: 0.1 to 0.1: 1.0. It has been found that the chemical softening composition is more effective when the polyhydroxy compound and the quaternary ammonium compound are premixed together first, preferably at a temperature of at least 40 ° C, before being added to the pulp. Either additional, or alternatively, the chemical softening compositions can be applied to the substantially dry tissue paper web, for example by means of a printing process (NB all percentages herein are by weight of dry fibers, unless otherwise indicated). that is specified otherwise). Examples of quaternary ammonium compounds suitable for use in the present invention include any unmodified or mono- or di-ester variations of dialkyldimethylammonium salts and well-known alkyltrimethylammonium salts. The examples include the di-ester variations of methylisulfate di (hydrogenated tallow) dimethylammonium and di-ester variations of di (hydrogenated tallow) dimethyl ammonium chloride. Without wishing to be bound by any theory, it is believed that ester entities lead to the biodegradability of these compounds. The commercially available materials can be purchased from Witco Chemical Company Inc. of Dublin, Ohio, under the trade name "Rewoquat V3512". Details of the analytical and test procedures are given in W095 / 11343, published April 27, 1995. Examples of polyhydroxy compounds useful in the present invention include polyoxyethylene glycols having an average molecular weight of between about 200 and 600, Special "PEG-400" is preferred. The tissue paper of the present invention can be made by common methods well known to those skilled in the art, such as, for example, by suitable pulp for dewatering using, for example, one or more felts and / or papermaking belts. For the present invention, conventional papermaking processes are preferred. Any process referred to in the present as conventional is a papermaking process that does not comprise a drying step by air passage. Alternatively, papermaking processes comprising a drying step by air passage can be used. These processes are described in the patent literature referred to hereinafter with respect to dried tissue by air passage. In accordance with the present invention, a paper tissue of at least 2 sheets is provided which is thick though smooth and therefore has a parameter of physiological surface smoothness of less than 700 microns, preferably between 650 microns and 50 microns, more preferably of 650 microns and 300 microns and in combination has a caliber per sheet greater than 0.09 mm, preferably between 0.09 mm and 0.5 mm, more preferably between 0.1 mm and 0.2 mm. In accordance with the present invention it has been found that the gauge per sheet is a relevant parameter to express how much gauge is provided to a profitable cost form, i.e., by a sheet. Any combination of variations provided above for the PSS parameter and the caliber per sheet is within the scope of the present invention.

Preferably, the tissue paper has a low size ratio per sheet with respect to the PSS parameter, the ratio is less than 6500 microns / mm, more preferably less than 5000 microns / mm, still more preferably less than 3000 microns / mm . A tissue paper according to the present invention has a first and a second surface, the surfaces are mutually opposite each other, and a thickness orthogonal to the first and second surface. The thickness is also called tissue caliper. The size of a tissue according to the present invention is preferably between 0.1 mm and 1 m, more preferably between 0.2 mm and 0.5 mm. Furthermore, a tissue paper according to the present invention preferably has a resistance to gusts of humidity greater than 100 g, preferably between 150 g and 500 g, more preferably between 250 g and 400 g. In a preferred embodiment of the present invention, a two-ply tissue paper is provided.

In a preferred two-sheet embodiment of the present invention, a sheet from a calendered tissue paper is provided while the other sheet is provided from a textured tissue paper, preferably etched. Without wanting to be linked to any theory, the following is believed: the engraving increases the total caliber of the product and with this also the caliber per sheet. Calendering typically increases the smoothness of the respective sheet and therefore a surface with a PSS parameter less is provided. "Calendering", in the sense in which it is used in the present, comprises high pressure calendering, the high pressure calendering denotes a calendering using a pressure per contact length of at least 3 kN / m, more preferably 5 kN / m at 50 kN / m, still more preferred at 10 kN / m at 25 kN / m. The high pressure calendering increases the smoothness of the tissue paper and thereby decreases the PSS parameter. According to the present invention, the individual sheets are preferably calendered, although alternatively several sheets can be calendered at the same time or a multiple sheet tissue paper set. Alternatively other techniques known in the art can be used to increase the smoothness of the tissue paper, such as, for example, selection of Fourdrinier meshes, felts and suitable bands, in the stages for dewatering, in addition to creping under suitable conditions (glue content, glue composition, impact angle with the scraper blade, creping aids). In addition, surface treatments, for example with a lotion, as discussed hereinafter, are within the scope of the present invention. "Textured", in the sense in which it is used herein, for a tissue paper refers to a tissue paper that is either air-dried, or recorded in volume, or comprises regions of different basis weights or dry with a texture or creped under suitable conditions (glue content, glue composition, impact angle with the scraper blade, creping aids), as explained below. "Engraving in volume", in the sense in which it is used herein, refers to an engraving that increases the caliber of the tissue paper by at least 5%, preferably 15%, more preferably 25% compared to the caliber of tissue paper before engraving in volume. Preferably, the volume engraving provides a pattern of recorded and unrecorded areas, which is imparted only to a number limited sheet of the multi-sheet tissue paper of the present invention in a process step, preferably only for one sheet in one of the process steps. The most external etched areas of the preference pattern extend over at least 75%, preferably 85%, most preferably 95% of the total surface area of the recorded sheets of paper. Protuberance to protuberance engraving is well known in the art as illustrated by US Pat. No. 3, 414,459 ceded jointly, granted on December 3, 1968 to Wells. The texture can also be imparted to the tissue paper by nested etching as illustrated by U.S. Patent No. 4,320,162, issued March 16, 1982 to Schuiz et al. Alternatively, the texture can be imparted to the tissue paper by dual sheet lamination etching as illustrated by United States Patent No. 5,468,323, assigned in a joint manner, issued November 21, 1995 to McNeil. Preferably, this volume engraving pattern is provided by steel-to-steel knurling, the protuberances preferably having an elliptical cross-section and a height in the range of 0.5 mm to 3 mm, greater preference in the range of 1 mm to 2 mm. Preferably, the volume engraving provides a ratio of areas recorded to unrecorded areas of between 1: 1 and 1:20, more preferably between 1: 2 and 1:15, still more preferably a ratio of 1: 5 and 1:10. To obtain the texture on either, or both of the first and second opposing surfaces, the tissue may be dried by air passage alternately. Air dried tissue is disclosed in U.S. Patent Nos. 4,529,480, issued July 16, 1985 to Trokhan; 4,637,859, granted on January 20, 1987 to Trokhan; 5,364,504, issued November 15, 1994 to Smurkoski et al .; 5,529,664, issued June 25, 1996 to Trokhan et al .; 5,679,222 issued October 21, 1997 to Rasch et al .; 5,714,041 granted on February 3, 1998 to Ayers et al .; 5,906,710, granted on May 25, 1999 to Trokhan, assigned jointly. Alternatively, tissue paper can be air dried and processed as set forth in U.S. Patent Nos. 5,429,686 issued July 4, 1995 to Chiu et al. and 5,672,248 granted on September 30, 1997 to Wendt et al.

Alternatively, the tissue paper can be textured by providing various regions of different basis weights, such that a tissue paper having multiple basis weight is presented. Tissue paper with multiple basis weight is set forth in U.S. Patent Nos. 5,245,025, issued September 14, 1993 to Trokhan et al .; 5,527,428 issued on June 18, 1996 to Trokhan et al .; 5,534,326 issued July 9, 1996 to Trokhan et al .; 5,654,076, issued August 5, 1997 to Trokhan et al .; 5,820,730, issued October 13, 1998 to Phan et al .; 5,277,761, issued on January 11, 1994 to Phan et al .; 5,443,691, issued August 22, 1995 to Phan et al .; 5,804,036 issued September 8, 1998 to Phan et al .; 5,503,715, granted on April 2, 1996 to Trokhan et al .; 5,614,061, issued March 25, 1997 to Phan et al .; 5,804,281 issued September 8, 1998 to Phan et al .; and 5,900,122 granted on May 4, 1999 to Huston, assigned in a joint manner. Alternatively, paper can be conventionally dried with a texture, for example, in accordance with US Pat. Nos. 5,549,790, issued Aug. 27, 1996 to Phan; 5,556,509, granted on September 17, 1996 to Trokhan et al .; 5,580,423, issued December 3, 1996 to Ampulski et al .; 5,609.72-5, granted on March 11, 1997 to Phan; 5,629,052 issued May 13, 1997 to Trokhan et al .; 5,637,194, issued June 10, 1997 to Ampulski et al .; 5,674,663, issued October 7, 1997 to McFarland et al.; 5,693,187 issued on December 2, 1997 to Ampulski et al .; 5,709,775 issued on January 20, 1998 to Trokhan et al .; 5,776,307 granted on July 7, 1998 to Ampulski et al .; 5,795,440 issued August 18, 1998 to Ampulski et al .; 5,814,190 granted on September 29, 1998 to Phan; 5,817,377 issued October 6, 1998 to Trokhan et al .; 5,846,379 issued on December 8, 1998 to Ampuls i et al .; 5,855,739 issued on January 5, 1999 to Ampulski et al .; 5,861,082 granted on January 19, 1999 to Ampulski et al., 5,871,887 granted on February 16, 1999 to Trokhan et al .; 5,897,745 issued on April 27, 1999 to Ampulski, et al .; and 5,904,811 granted on May 18, 1999 to Ampulski et al., assigned in a joint manner. In a rather preferred embodiment of the present invention, a three-ply tissue paper is provided. Preferably at least one sheet is calendered and at least one sheet is textured, of preference is recorded. More preferably two sheets are calendered and one is engraved, preferably placed between them. This particular embodiment has the advantage of providing a smooth surface to the user on either side. Alternative embodiments of the present invention are for example those with any number of textured sheets, preferably engraved placed between two outer calendered sheets, one of these is a four-ply tissue paper with two engraved sheets placed between two calendered sheets. When two or more sheets of tissue paper are combined to form the tissue paper, the sheets may optionally be joined together for example, by means of gumming or engraving, herein referred to as "joint engraving". Gumming is less preferred because it tends to result in a softer and more rigid product. "Engraving by joining," in the sense in which it is used herein, refers to an engraving by which all sheets of a multi-sheet tissue, according to the present invention, are recorded in a process of one step Preferably, the engraving by union does not affect or at least not to a large extent the smoothness of any sheet Calendered Therefore, preferably the tissue has a non-etched surface on a major portion of the surface area of the tissue, preferably on the first and second surface. In the sense in which it is used herein, this means that the tissue has one or more regions that do not comprise an etch and, optionally, one or more regions that comprise an etch, and that the region does not. comprises an etch by bond is at least 50%, and as large as 99%, of the surface area of the tissue. More commonly, the regions comprising a joint engraving are located near the edge of the tissue (for example along two or four edges); and the regions comprising a joint engraving can also be used for decorative purposes (for example to create a pattern or to spell a logo or trade name). The region that does not comprise an engraving by joining is the continuous region between and / or around the region comprising a joint engraving. The engraving by union of preference is carried out by steel-to-steel end-to-end engraving. If you are going to use glue to join the sheets of a multi-sheet tissue paper, according to With the present invention, the glue is preferably applied unevenly with respect to the surfaces of the sheets to be bonded. Therefore, the glue preferably is not applied by means such as a spray nozzle, because these nozzles apply the glue in a regular manner without any preference for particular areas of the tissue, even when the glue is applied to form the glue. a discontinuous network. A textured tissue paper, preferably etched, comprises raised portions. In a preferred embodiment of the present invention, the glue will be applied only to these elevated portions of the tissue paper. Because mainly these raised portions are in context with adjacent sheets, in particular with adjacent calendered sheets, the application of the glue to these raised portions is sufficient to ensure a good bond, although it avoids the application of a quantity of glue, which imparts easily stiffness to paper isu. A preferred method for applying the glue to a tissue sheet is to apply the glue by impression rollers. Alternatively the glue can be applied by meltblowing, to form areas of preferential applications of glue, for example glue strips. The tissue paper and preferably one or both surfaces, more preferably both surfaces of the tissue optionally can be treated additionally with a lotion. A lotion can contribute to the smoothness of the tissue paper, and with this decrease its PSS parameter. The lotion may comprise softening / disintegrating agents, emollients, immobilizing agents and mixtures thereof. Suitable softening / disintegrating agents include quaternary ammonium compounds, polysiloxanes, and mixtures thereof. Suitable emollients include propylene glycol, glycerin, triethylene glycol, spermaceti or other waxes, petrolatum, fatty acids, fatty alcohols and fatty alcohol ethers having from 12 to 28 carbon atoms in their fatty acid chain, and mixtures thereof. Suitable immobilizing agents include polyhydroxy fatty acid esters, polyhydroxy fatty acid amides, and mixtures thereof. Other optional components include perfumes, antibacterial assets, antiviral assets, disinfectants, pharmaceutical actives, film formers, deodorants, opacifiers, astringents, solvents and the like. Particular examples of lotion components include camphor, thymol and menthol. A process according to the present invention can use any tissue paper made by any method known in the art, preferred methods are disclosed herein. The process comprises a step for supplying the tissue paper by unwinding at least two sheets, preferably three sheets, of a corresponding number of rolls of the patent. The process comprises an additional step of applying a texture pattern to at least one sheet, preferably by volume engraving as set forth herein. The process also comprises a step of calendering at high pressure at least one sheet using calendering pressures as set forth herein. In addition, the process comprises a step of juxtaposing the sheets to form a multi-sheet tissue. A more preferred process further comprises a step of applying lotion to the sheets, which will form the outer sheets of the multi-sheet tissue paper, more preferably the lotion is applied only to the surfaces that will form the external surfaces of the multi-sheet tissue. In addition, a preferred process comprises a step of joining the juxtaposed sheets by etching, which is referred to and described above as a joint engraving. Optionally, the present process can also comprise the application of glue, preferably only to the raised portions of the textured sheets.

Test methods The caliber is measured according to the following procedure: the tissue is preconditioned from 21 ° to 24 ° C and from 48 to 52% relative humidity for two hours before the gauge measurement. If you are measuring the size of the toilet paper, first remove and discard 15 to 20 sheets. If the caliber of facial tissue is being measured, the sample is drawn near the center of the package. The samples are selected and then conditioned for an additional 15 minutes. The caliper of the multi-sheet tissue paper, in the sense in which it is used herein, is the thickness of the paper when it is subjected to a compression load of 14.7 g / cm. Preferably, the caliber is measured using a Thwing-Albert xe low load micrometer, Model 89-11, available from the Thwing-Albert Instrument Company of Philadelphia, Pa. The gauge per sheet is the total gauge of the multi-sheet tissue paper divided by the number of compressed sheets. For a single sheet tissue gauge per sheet and the gauge are identical. The decorated regions, perforations, edge effects, etc., of the tissue should be avoided if possible. The resistance to moisture bursts is measured using an electronic burst tester and the following test conditions. The burst tester is a Thwing-Albert Cat burst tester. No. 177 equipped with a 2000 g load cell. The burst tester is supplied by the Thwing-Albert Instrument Company, Philadelphia, PA 19154, USA. Take eight tissue papers and stack them in pairs of two. Use scissors, cut the samples so that they are approximately 228 mm in the machine direction and approximately 114 mm in the cross machine direction, each of the two unit thicknesses of the finished product. First let the samples age for one to two hours by joining the stack of samples together with a small paper clip and "unfold" the other end of the stack of samples to separate the sheets, this- allows the circulation of air between them. Suspend each sample stack with a clamp in a forced air oven at 107 ° C (± 3 ° C) for 5 minutes (± 10 seconds). After the warm-up period, remove the sample stack from the oven and cool for a minimum of three minutes before the test. Take a strip of the sample, hold the sample by the edges in a narrow transverse direction, immerse the center of the sample in a tray filled with approximately 25mm of distilled water. Leave the sample in the water for (4.0 ± 0.5) seconds. Remove and drain for three (3.0 ± 0.5) seconds holding the sample in such a way that the water runs in the transverse direction. Continue with the test immediately after the draining step. Place the wet sample on the lower ring of the device to hold the sample with the outer surface of the product facing up, so that the wet portion of the sample completely covers the open surface of the ring to hold the sample. If wrinkles appear, discard the sample and -repeat with a new sample. After the sample is placed properly in place on the lower ring, operate the switch that lowers the upper ring. The sample that will be tested now is tightened securely in the unit to hold the sample. Start the burst test immediately at this point by pressing the start button. The piston will begin to rise. At the point where the sample tears or breaks, report the maximum reading. The piston will automatically return and return to its original start position. Repeat this procedure on three more samples for a total of four tests, that is, 4 repetitions. Report the results, as an average of the four repetitions, to the nearest gram. For the measurement of physiological superficial smoothness, which reports the PSS parameter, a sample of tissue paper is selected that avoids wrinkles, tears, perforations, or deviations of thickness of macroscopic monoplanarity. The sample is conditioned at 22 to 24 ° C and 48 to 52% relative humidity for at least two hours before the test. The sample is placed on a motorized table and magnetically secured in place. You can select any face of the sample for measurement, with the condition that all traces are "taken from the same face." The physiological surface smoothness is obtained by scanning the tissue paper sample in any direction with a profile meter to obtain the displacement in the Z direction as A displacement function in the Z direction is converted to an amplitude against the frequency spectrum by means of a Fourier Transform.The spectrum is then adjusted to respond to human touch using a series of filters. filtered amplitude frequency are added from 0 to 10 cycles per millimeter to provide the result.The sample of tissue paper is approximately 100 millimeters x 100 millimeters in size and is mounted on a motorized table. While any suitable table will suffice, a table with surface tester model KES-FB-4NKES-SE, available from Kato Tech Company Limited of Koyota, Japan, or a CP3-22-01 Mini Precision DCI table that has been used, has been found suitable. a NuStep 2C NuLogic Two-Step Stepper Motor Controller in closed-loop control mode. The table has a constant drive motor that travel at speed - 1 millimeter per second. The sample is scanned 30 millimeters in the forward direction transversely indexed one millimeter, then it is returned. Data is collected from the 26-millimeter center of the scan in both the forward and backward directions. The first and last 2 millimeters of each scan are ignored and are not used in the calculations. The profile meter has a probe with a tip radius of 2.54 microns and an applied force of 0.20 grams. The capacity variation is calibrated for a displacement in the total Z direction of 3.5 millimeters. With respect to the scanning distance of the sample, the profile meter detects the displacement in the Z direction of the punch in millimeters. The output voltage of the capacity controller is digitized at a speed of at least 20 points per second. With respect to the total of 26 millimeters the exploration varies, 512 pairs of data points of surface height are obtained for the directions both forward and backward of a scan. The profile meter is mounted above the sample table so that you can measure the surface topography. A suitable profile meter is an EMD 4320 Wl Vertical Displacement Transducer, which has an EPT 010409 punch tip, and an EAS 2351 Analog Amplifier. This equipment can be obtained from Federal Products of Providence, Rhode Island. The pairs of digitized data are imported into a standard statistical analysis package for further analysis. Suitable software analysis packages include SAS from Cary, North Carolina, and preferably LabVIEW Instrument Control Software 3.1 available from National Instruments of Austin, Texas. When LabVIEW software is used, the row data pairs linking the surface height and time of the individual scans are approximately centered on the mean using the Mean analysis tool. i in LabVIEW software. The 512 data points of each of the 16 traces are converted to 16 amplitude spectra using the Spectrum.vi tool of Amplitude and Phase. Each spectrum is then smoothed using the method described by the PROC Spectrum Method of the SAS software. The LabVIEW smoothing filter values of 0.000246, 0.000485, 0.00756, 0.062997, 0.00756, 0.000485, are used, 0. 000246. The output of this tool is taken as the Amp Spectrum Mag (vrms). The amplitude data are then adjusted for human touch response using a series of frequency filters designated from the Verrillo data on vibrotactile thresholds as a function of vibration frequency as established in the Journal of Acoustical Society of America, in the article entitled "Effect Of Contactor Area On The Vibrotactile Threshold", Vol. 35, 1962 (1963). The data mentioned above are reported in a time domain as cycles per second and are converted to the spatial domain in cycles per millimeter. The conversion factor and the filter values are found in the procedure shown at the International Paper Physics Conference of 1991, TAPPI Book 1, more particularly the article entitled "Methods for the Measurement of The Mechanical Properties of Paper tissue" of Ampulski , et al., and found on page 19, which uses the specific procedure shown on page 22 entitled "Physiological Surface Smoothness". The response of the filters is set to 0 below the minimum threshold and above the maximum response frequencies and varies from 0 to 1 between the same as described by the article by Ampulski et al. mentioned above Physiologically adjusted frequency amplitude data are obtained by multiplying the amplitude spectra described above by the appropriate filter value at each frequency. A suitable amplitude spectrum and filtered amplitude spectrum are illustrated in Figure 5 of the Ampulski et al. previously mentioned. The frequency amplitude curve adjusted by Verrillo is added point by point between 0 and 10 cycles per millimeter. It is considered that this is the physiological surface smoothness. The eight values of forward physiological surface smoothness and the eight inverses obtained in this way are then averaged and reported in microns. The measurement of physiological surface smoothness used by SAS software is described in U.S. Patent Nos. 4,959,125, issued September 25, 1990 to Spendel; 5,059,282, issued October 22, 1991 to Ampulski et al .; 5,855,738, granted on January 5, 1999 to Weisman et al., And 5,980,691, granted on November 9, 1999 to Weisman et al., Assigned in a joint manner.

Any face of the tissue can be selected for the measurement of smoothness, with the condition that all the traces are taken from the same face. If either side of the tissue meets any of the criteria of smoothness shown herein, the entire tissue sample is considered to be within that criteria. Preferably, both sides of the tissue meet the above criteria.

EXAMPLE An aqueous pulp comprising 3% by weight of North Softwood Kraft fibers (NSK) was prepared in a conventional repulper. The NSK pulp was gently refined and a 2% solution of the permanent wet strength resin (Kymene 617) was added to the NSK material pipe at a rate of 0.9% by weight of the total dry fibers. The absorption of the permanent wet strength resin on the NSK fibers is intensified by an in-line mixer. A 1% solution of the dry strength resin (carboxymethylcellulose) is added to the NSK material before the fan pump at a rate of 0.14% by weight of the total dry fibers. Pulp NSK was diluted to approximately 0.2% consistency in the fan pump. A chemical softening composition was prepared comprising quaternary ammonium chloride of diethyl dimethyl ester of tallow dihydrogenated and polyoxyethylene glycol, having an average molecular weight of 400 (PEG-400). The PEG-400 was heated to about 66 ° C, and the quaternary was dissolved in the molten PEG-400 in such a way that a homogeneous mixture was formed. An aqueous pulp comprising 3% by weight of eucalyptus fibers was prepared in a conventional repulper. A 1% solution of the chemical softening composition was added to the pipe of eucalyptus materials at a rate of 0.09% by weight of the total dry fibers. The eucalyptus pulp was diluted to approximately 0.2% consistency in the fan pump. The 1% solution of the chemical softening composition was also added to the NSK pulp after the subsequent addition of CMC and before the dilution of the pulp to approximately 0.2% in the material pump. The two pulps were combined in such a way that the proportion of NSK to eucalyptus fibers was 40:60 and the resulting pulp was deposited, by means of a Single layer head on a Fourdrinier mesh to form an embryonic web. The dewatering occurred through the Fourdrinier mesh and was assisted by a baffle and vacuum boxes. The embryonic web was transferred from the Fourdrinier mesh, to a fiber consistency of approximately 20% at the transfer point, for a conventional drying felt. The web was then transferred to the surface of a Yankee dryer with a sprayed creping adhesive comprising 0.25% aqueous polyvinyl alcohol (PVA) solution. The fiber consistency was increased to an estimated 96% before the dry creping of the weft with a scraper blade. The scraper blade had a chamfered angle of approximately 25 ° and was positioned with respect to the Yankee dryer to provide an impact angle '' of approximately 81 ° 'The Yankee dryer was operated at approximately 4 m / s and the uncalendered, dry paper was formed into 1-sheet rolls on a reel.Three of these 1-sheet rolls were taken for a return operation. roll off line to form rolls of 3 sheets that are subsequently converted into a tissue paper product of 3- sheets, which has a total dimension of approximately 210 square mm. The 3-sheet rolls were produced by simultaneously unrolling 3 of the 1-sheet rolls, the central sheet running through a rubber-to-steel volume engraving operation and rewinding the two external sheets without engraving with the central sheet engraved to form a roll of 3 leaves. For the engraving of the center sheet a smooth rubber roller was loaded against a patterned steel roller. The patterned steel roller has raised elliptical engraving protrusions of approximately 1.7mm in depth that have a principal axis on the surface of approximately 2mm and a secondary axis of approximately 1mm. The engravings are arranged in a repeating pattern of concentric diamonds consisting of approximately 72 protuberances in an area of 900 mm2. The 3-leaf roll was subsequently converted into a 3-leaf tissue product. The three-ply web was unrolled and subjected to an etching step before folding-The margin of the tissue paper product, which extends approximately 15mm from the edge, was recorded following the process described in W095 / 27429, published October 19, 1995. The main portion of the surface area of the tissue paper product (i.e., the entire surface area within the 15mm range) was unrecorded. The tissue was also decorated by engraving the commercial name on a small area of the area not previously recorded and four patterns of decorative leaves were added where they were recorded in the area not previously recorded. The lotion was printed on each of the external surfaces of the 3-sheet frame via a two-step application process before bending. The lotion was an aqueous solution of quaternary ammonium chloride of diethyl dimethyl ester of tallow dihydrogenated. The printing was carried out by running the 3-ply web through two consecutive printing stations consisting each of an engraved anilox roll and a pair of rubber reinforcement rolls. The anilox roll was recorded at a cell volume of about 3 ml per square meter, and with lotion feed from a closed supply chamber designed to fill the volume of etching with the lotion. A separation of 0. 35mm between the anilox roller and the reinforcement roller, and the 3-leaf weave was run through this separation, transferring the lotion to the surface touching the anilox roller. The frame was then run through the second printing station with a pair of identical anilox / rubber rollers at a 0.35mm spacing. The pairs were placed in such a way that the second anilox roller contacted the surface still without lotion, transferring the lotion thereto. This arrangement transferred 0.45% of the active quaternary by dry weight of the finished 3-leaf tissue. The tissue paper obtained by the process described above had a basis weight of 54 g / m2, a total caliber of 0.35 mm, a caliber per sheet of 0.12 mm, a resistance to gusts of humidity of 375 g and a PSS parameter of 620 microns. A second example consists of the substrate produced described above, in which the outer sheets are run through a softening calendering roll. It was further found that calendering from 12 kN / m to 15 kN / m reduces the PSS parameter to approximately 500 to 450 microns.

Claims (20)

1. CLAIMS 1. A tissue paper, the tissue paper comprises at least two sheets, the tissue paper has a caliber and a caliber per sheet, the tissue paper also has a parameter of physiological surface smoothness, characterized in that the parameter of physiological superficial smoothness is lower at 700 microns and the size per leaf is greater than 0.09 mm.
2. 2. The tissue paper according to claim 1, characterized in that the parameter of physiological surface smoothness is 650 microns up to 100 microns.
3. 3. The tissue paper according to any of the preceding claims, characterized in that the gauge per sheet is from 0.1 mm to 0.2 mm.
4. 4. The tissue paper according to any of the preceding claims, characterized in that the ratio of the physiological surface smoothness parameter to the gauge per sheet is less than 5000 microns / mm.
5. 5. The tissue paper according to any of the preceding claims, the tissue paper "has a resistance to moisture bursts, characterized in that the resistance to moisture bursts is 150 g up to 500 g.
6. 6. The tissue paper according to any of the preceding claims, the tissue paper has a resistance to moisture bursts, characterized in that the resistance to moisture bursts is 250 g up to 400 g.
7. 7. The tissue paper according to any of the preceding claims, characterized in that it does not comprise drying paper by air passage.
8. 8. The tissue paper according to any of the preceding claims, characterized in that at least one of the sheets comprises a volume engraving and at least one of the sheets does not comprise a volume engraving.
9. 9. The tissue paper according to claim 8, which is a termed face because at least one sheet that does not comprise the engraving in volume is calendered.
10. 10. The tissue paper according to any of the preceding claims, characterized in that said tissue paper comprises at least three sheets.
11. 11. The tissue paper according to claim 10, comprising two outer sheets and at least one inner sheet, characterized in that the outer sheets do not comprise the engraving in volume and at least one of the internal sheets comprises the engraving in volume.
12. 12. The tissue paper according to claim 11, characterized in that at least one of the outer sheets is calendered.
13. 13. The tissue paper according to any of the preceding claims, characterized in that the volume engraving is provided by a pattern of engraved and non-engraved areas, characterized in that the ratio of areas recorded to the unrecorded areas is from 1: 1 to 1:20.
14. 14. The tissue according to any of the preceding claims, characterized in that at least one sheet comprises a lotion.
15. 15. The tissue paper according to any of the preceding claims is characterized in that the sheets are not bonded by adhesive.
16. 16. The tissue according to any of the preceding claims, characterized in that the sheets are joined by engraving.
17. 17. The process for making the tissue paper according to any of the preceding claims comprises the steps of: - unrolling at least two sheets, preferably three sheets of a main roll - applying a texture, preferably a pattern of engraving to at least one leaf - calendering at high pressure at least one leaf - juxtaposing leaves to form a multi-leaf tissue
18. 18. The process according to claim 15, further comprising a step of applying a lotion to at least one of the calendered sheets.
19. 19. The process according to any of the preceding claims further comprising a step of recording all the sheets.
20. 20. The process according to any of the preceding claims which does not comprise the application of a glue by printing rollers.