MXPA00008588A - Cotton linter tissue products and method for preparing same - Google Patents

Abstract

A soft, bright and strong tissue paper product and a process for preparing such a tissue paper product is provided. The tissue paper product is prepared from raw cotton linter fibers and demonstrates unexpected medical benefits or advantages in addition to a balance of properties.

Description

SILK PAPER PRODUCTS OF COTTON EDGE FIBERS AND METHOD TO PREPARE THE SAME FIELD OF THE INVENTION The present invention relates generally to tissue paper products made from cotton fluff fibers. More specifically, the present invention relates to tissue paper products from cotton fluff fibers that exhibit a balance of properties including reduced softness and roughness and strength. The present invention also relates to a method for preparing such tissue paper products.

BACKGROUND OF THE INVENTION Silk tissue products, such as facial tissue papers and toilet paper, are relatively low density, lightweight papers that are undoubtedly recognized as a fundamental commodity. The primary source of fibers used in the preparation of these tissue paper products are wood pulp fibers having an average fiber length of less than 1 millimeter (<1 mm) to about 2 mm. Such fibers include chemical wood pulps, such as sulphite process wood pulps and Ref. 0122980 sulphate (i.e., Kraft), and mechanical wood pulps, such as defibrated wood, ThermoMechanical Paste (TMP) and Chemical Pulp. -Term Mechanics (CTMP). Pastes derived from both deciduous (that is, hardwood) and coniferous (that is, softwood) trees are used as sources of fiber, as well as fibers derived from recycled paper. These prior art tissue paper products also comprise minor amounts of chemical functional agents including wet strength and dry strength binders, retention aids, surfactants, sizing, chemical softeners and the like, and show as A balance of properties including strength and smoothness is reported. It is noted that a portion of these prior art wood-based tissue paper products have a high degree of dusting or lint formation. In addition, the inherent degree of roughness associated with this fiber source, coupled with the presence of residual processing agents, results in a tissue paper product that could act as an irritant to users.

The prior art tissue paper products mentioned above are made from sheets of paper prepared using conventional papermaking processes and techniques, which include the steps of forming a wood pulp or aqueous fibrous slurry, depositing the slurry in a foraminous surface, such as a Fourdrinier wire or the surface of a shaping cylinder employed in a cylinder mold papermaking machine, remove water from the slurry deposited by, for example, gravity or vacuum-assisted drainage, followed by adhering the resulting semi-dry sheet to the surface of a Yankee desiccator, completely removing the water from the semi-dry sheet by evaporation, removing the dried sheet essentially from the Yankee desiccator, and winding the resulting sheet on a reel.

The papermaking fibers that are used in these tissue paper products are prepared by releasing the individual fibers of the wood pulp in an aqueous slurry using conventional pulping methods and refining, if necessary, to reduce the length of fiber.

The tissue paper industry has recognized and sought for a long time to please a segment of the general public that has existing medical conditions, such as external physical ruptures or diseases (eg, swollen tissue), or that has shown an inclination towards reactions hypersensitive to existing tissue paper products. Attempts to please these individuals include offering tissue paper products that are free of fragrances, preservatives and other components or non-essential ingredients that may aggravate existing conditions or that may promote or favor an allergic reaction or other physical reaction to the same. However, even these altered products, probably due in part to their inherent degree of harshness, continue to present problems to this segment of the general public.

Economic and environmental concerns have driven a recent trend in the tissue paper industry to reduce the amount of wood pulps used in products, such as facial tissue papers and toilet paper. Methods of achieving such reduction include the replacement of wood pulp fibers with high performance fibers or with fibers which have been recycled. Another such method is described in U.S. Patent 5,611,890 by Vinson et al. and comprises the replacement of wood pulp with an easily available, inexpensive filler material, such as kaolin clay and calcium carbonate. Unfortunately, these methods generally tend to adversely affect the softness or tactile feel of these products.

The pleasant tactile feel of cotton has been recognized for a long time and the use of cotton fibers has been common in certain parts of the paper industry for a number of years. However, extending the use of this fiber source to tissue paper products presents significant technical and manufacturing difficulties at each stage in the production process from the selection of untreated cotton linters to the pulp reduction process. erase cotton and the process of manufacturing tissue paper.

The untreated cotton lint obtained from cottonseed is characterized by grades that vary considerably in length, foreign particle or dirt content and in the degree of remaining classified fiber and juniper liquor specks. For example, the first cut slips, which are used mainly in banknotes and stationary paper and high quality documents, are long (ie,> 10 mm) and contain sorted fibers and remaining juniper liquor speck. . As a result, significant refining and cleaning problems arise when attempting to prepare a cotton lint paste. The additional processing problems occur when these cotton lint pastes are used to prepare facial tissue papers and toilet paper. It has been observed by the present applicant that an excessive "binding" of the fibers occurs when an aqueous fibrous slurry containing such untreated cotton wool is passed through the pumps and cleaners in a tissue paper production process. conventional. It has also been observed that even if the fibers are subsequently shortened by refining and beating, in an attempt to improve the physical characteristics of the resulting sheet, the sheet is "carañada" with hard pills.

The cotton strip of second cut and third cut varies depending on the country of origin. For example, the second-court erasure of Asia and Europe are significantly longer than the second American eraser and has a tendency to have pills, but to a lesser extent than previously observed. The Asian and European third cut is smaller than the second American cut, but has a higher dirt content.

The nature of cotton fluff fibers has long been identified as a contributor to the observed plugging of disc refiners used in domestic wood pulp and tissue paper factories. Regarding the specific double disc refiners used in the domestic pasta factories, it has been observed that if the opening between the refiner's barriers is too narrow and excessively shallow to allow the fiber to pass through clearly, these openings will be covered with lumps hard fibers that result from a loss of refining capacity and defects in wood pulp sheets in the form of nits, pills and hard strands.

The different grades of eraser wood pulp are commercially available. However, it is noted that no single grade of these commercially available wood pulps can be used to manufacture tissue paper products that exhibit a balance of properties including reduced softness and roughness and strength. further, the numerical representations of the relevant fiber lengths cited by the wood pulp manufacturers are both inadequate and misleading. In addition, it has been observed that an apparent equivalence apparently among commercially available wood pulps does not guarantee the preparation of equivalent tissue paper products.

Two instruments (ie, a Clark Classifier and a Bauer McNett Classifier) are used in the cotton fluff industry to quantify the length of the relative fiber.

Both instruments operate with the principle of collecting fibers from slurries diluted in screens of decreasing asperity.

For example, a Clark Sorter is usually equipped with 14, 30, 50 and 100 mesh screens from the United States. An aqueous fibrous slurry is first passed through the mesh screen 14. The long fibers are retained in the screen or in an upward reservoir stream of the screen. Then this process is repeated in screens 30, 50 and 100 mesh. Then each tank is drained and the fibers are collected and weighed. The percent by weight of fibers retained in each screen and associated deposit is a numerical representation of the relative fiber length. Generally, the percent retained in the 14 mesh screen is quoted in the specifications for the different grades of wood pulp.

As noted above, despite similar specifications, cotton lint can have significantly different characteristics. By way of example, a grade sold as "refined first cut cotton gum" will start with a relatively long fiber, but will be hard refined and cut before the wood pulp dries. The grade specifications will include a fiber length of 45 to 55% in the US 14 mesh. This so-called "first cut" wood pulp has a marked tendency to bind and form pills, but produces a tissue paper product that has good paper strength. In comparison, a grade sold as a filter paste will start production with a relatively short fiber blend, but will be refined enough only to form a sheet in the wood pulp desiccator. The grade specifications will include a fiber length of 40 to 50%. This degree of filter paste forms few strands or pills, but produces a tissue paper product that has a relatively poor paper strength.

In addition to the uncertainties presented by the inherent variety within each grade of the untreated cotton lint and each commercial grade of cotton lint, it is further observed that cotton fibers become more easily entangled than wood fibers, with which they still present additional processing difficulties.

The conventional tissue paper manufacturing equipment is designed to fit or process clean wood pulp fibers having an average fiber length from < 1 mm to approximately 2 mm. As a result, the use of cotton lint wood pulps in the preparation of tissue paper products using such conventional equipment is problematic immediately. Process areas where the use of cotton lint paste is at least compatible with conventional tissue paper equipment are in the areas of raw material preparation, pulp reduction, pumping, refining and screening. It has been observed that the use of these pastes results in an immediate complete plugging of the equipment where the screens and the refiner (s) employed herein can not provide the degree of cleaning or difficult refining necessary without plugging. It is noted that the refiners used in conventional tissue paper factories are generally oversized, since they can not provide the horsepower needed to process such cotton lint pastes.

SU-A-417 566 (SU * 566) describes a wood pulp for paper to make paper for sanitary-hygienic and domestic uses. In paper covered by this reference is a paper that has a basis weight of 60 ± 5 g / m2 and, as such, does not constitute a type of tissue paper. In fact, the paper of the document SU '566 is acceptable according to what is said for the production of paper articles for sanitary-hygienic and domestic uses during short-term use without resisting washing (underwear, clothes, very simple types of clothing) ).

SU '566 also describes the use of both cotton processing waste and flax processing waste in its paper pulp. The phrase "cotton-fluff processing waste of types III and IV" is not defined in this reference, but is understood to refer to waste products of the textile industry - that is, mixtures of short-lived wastes and fibers that measure 6.5 to 19 mm. The length of the fibers (ie 6 to 8 mm) is not reduced during the grinding.

EP-A-0 824 160 (EP'160) refers to a process for producing wood pulp for paper used in the manufacture of high weight basis papers that include high quality security papers, such as banknotes. and the like. The wood pulp of the EP'160 document is prepared from fibers of annular plants which include cotton, linen, straw, bagasse, banana stems, cotton linters, hemp, etc.

Where EP'160 relates to wood pulps used in the manufacture of high-weight paper, the problems that relate to the degree of fiber reduction and the characteristics of the fiber source are not critical to the integrity of the sheets prepared from these wood pulp and, therefore, are not directed by this reference.

GARY A. Smook: Handbook for Pulp and Paper Technologists, pages 195-196, shows that Hollander type beaters are used to handle cotton finishes. This reference, however, does not teach or suggest that such finishes can be used in the production of low density, lightweight papers or silk papers.

N.K. AHUJA et al .: Pulp and Paper Manufacture, pages 111-112, explains that cotton fluff fibers are; the treatment (including refining) of such fibers; the average fiber lengths of sawn timbers and first and second cuts, and the use of cotton linters in papers containing cotton.

This reference, however, fails to teach or suggest the use of cotton linters in tissue paper products. Therefore, it is not surprising that although this reference identifies the fact that the quality of the cotton fluff varies, it fails to teach the necessary characteristics of this fiber source (eg, content of foreign particles or dirt and the degree of fiber). classified and juniper liquor specks).

GB 1 239 311 A (GB'311), an English equivalent of DE-A-1 916 063, relates to an improved method of preparing low lignin non-lignin fibrous materials for use in papermaking .

The improved method specifically comprises the use of a modified drum-extractor type washing machine to process these fibrous materials before transferring them to the whipping motor. This reference, however, does not teach or suggest that such fibrous materials can be used in the production of low density, lightweight papers or silk papers.

U.S. Patent No. 3,737,369 (US '369) generally refers to an improved bagasse paper. According to this reference, bagasse and similar plant material fibers have a relatively high hemicellulose content and that a substantial proportion of this material is maintained after a reduction to wood pulp from the conventional soda digestion process. Due to this characteristic, the bagasse wood pulps are said to be extremely hydrated and are typically observed to be refined very easily and are inherently very weak, especially with respect to the paper-punched resistance made therefrom.

To address this problem, US '369 teaches the preparation of wood pulp for paper from combinations or blends of lignocellulosic fibers at 98 to 85% by weight of plant materials, such as sugarcane bagasse and cotton lint. at 2 to 15% by weight. The wood pulp from the combinations reportedly take the refining energy and produce paper that has improved strength characteristics compared to the 100% bagasse wood pulp finish. The cotton linters are used for the sole purpose of reducing the hydration ratio of the bagasse fibers.

US '369 continuously teaches the use of wood pulps prepared from cotton lint only. As clearly shown in Table VI of this reference, the Canadian Standard Freedom beaten times of 650 ml and 500 ml for wood pulps prepared from cotton gum only (ie, comparative procedures B and C) are by over three times greater than the beating times recorded for the wood pulps prepared according to the invention described. More importantly, papers made from wood pulps prepared from 4 mm short cotton linters (ie, Comparative Example C) show greatly reduced stress rupture and breakage factor values compared to papers made from wood pulps prepared from mixtures of bagasse / cotton lint fiber of the subject invention (ie, Examples 1, 2 and 3).

JP-A-56 068 178 (JP'178) describes a method for digesting untreated cellulosic material in an alkaline solution containing hydrogen peroxide. The method serves to avoid the generation of toxic gases and, likewise the present inventive process, serves to eliminate the need for a mechanical and chemical pre-treatment.

JP-A-61 012 991 (JP'991) discloses a method for continuously digesting a mixture of cotton linters, leaves, seed husk and cotton with oxygen and alkali (eg, sodium hydroxide, sodium carbonate or sodium carbonate). sodium bicarbonate) .

There is a need in the art for a product based on cotton fiber that meets the needs of individuals with existing medical problems and the preferences of average consumers. Therefore, it is an object of the present invention to overcome the limitations and disadvantages detailed above.

It is a more specific objective of the present invention to provide a tissue paper product prepared from cotton fluff fibers.

It is an even more specific objective to provide a tissue paper product that exhibits a balance of properties that include softness or reduced roughness and strength.

It is still a more specific objective to provide a tissue paper product that reduces or eliminates any of the adverse reactions that result from the use of such a product by individuals who have existing medical conditions or hypersensitivities.

It is another object of the present invention to provide a process for preparing cotton fluff paper products that serve to overcome the technical and manufacturing problems presented by this fiber source.

It is still an additional objective to provide a process for preparing a cotton lint paste that can be easily processed in domestic tissue paper factories.

BRIEF DESCRIPTION OF THE INVENTION The present invention therefore provides a process for preparing a cotton lint paste, which comprises subjecting an aqueous cotton lint slurry comprising cotton lint fibers having an average fiber length of from about 2 to about 16 mm. to prolonged, gradual refinement by a Hollander type beater for a period from about 2 to about 3 hours until an average fiber length of about 0.3 to about 3.0 mm is obtained.

The present invention also provides a soft, strong tissue paper product prepared from untreated cotton fluff fibers having an average fiber length of from about 2 to about 16 mm and comprising: cotton fluff fibers having an average fiber length from about 0.3 to about 3.0 mm and an effective amount of a cationic starch derivative.

The present invention further provides a process for preparing the tissue paper product, which comprises: selecting untreated cotton fluff fibers or mixtures thereof; mechanically clean the selected fibers; digest mechanically cleaned fibers to form a wood pulp; whiten wood pulp; beating or refining bleached wood pulp until an average fiber length of about 0.3 to about 3.0 mm is achieved; and form the bleached and refined wood pulp on the sheet.

The features and advantages mentioned above and other features and advantages of the present invention will become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a scanning electron micrograph (magnification 1100x) of the bath tissue or toilet tissue product of the present invention; Figure 2 is a scanning electron micrograph (magnification 1100x) of a bath tissue or toilet tissue product manufactured by The Proctor & Gamble Company, Inc. under the trade name "CHARMIN" (tissue paper for bathroom CHARMIN "); Figure 3 is a scanning electron micrograph (magnification 1100x) of a bath tissue or toilet tissue product manufactured by Kimberly-Clark Corporation under the trade name "COTTONELLE" (COTTONELLE bath tissue); Figure 4 is a scanning electron micrograph (magnification 11OOx) of the facial tissue paper product of the present invention; Y Figure 5 is a scanning electron micrograph (magnification 11OOx) of a facial tissue paper product manufactured by Kimberly-Clark Corporation under the trade name "KLEENEX" (KLEENEX facial tissue paper).

Figure 6 is an 8 mm electron micrograph (8900x3.7 magnification) of a skin sample obtained by a 2 mm punch biopsy of the facial areas showing the skin layers of stratum corneum and viable epidermis; Figure 7 is an 8 mm electron micrograph (8900x3.7 magnification) of a cutaneous sample obtained by means of a 2 mm punch biopsy of the facial areas showing ultrastructural changes for the stratum corneum layer resulting from 5 days of use of KLEENEX facial tissue paper; Figure 8 is an 8 mm electron micrograph (8900x3.7 magnification) of a cutaneous sample obtained by a 2 mm punch biopsy of the facial areas showing the ultrastructural changes for the stratum corneum layer resulting from 5 days of use of a facial tissue product manufactured by The Proctor & Gamble Company, Inc. under the trade name "PUFFS PLUS" ("PUFFS PLUS tissue paper"); Y Figure 9 is an 8 mm electron micrograph (8900x3.7 magnification) of a skin sample by a 2 mm punch biopsy of the facial areas showing the ultrastructural changes to the stratum corneum layer resulting from 5 days of use of the facial tissue paper product of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention comprises the surprising discovery that the use of cotton fluff fibers as the sole or predominant fiber source in the preparation of tissue paper products, such as facial tissue paper and toilet paper, and other non-woven products, It is not only viable, but serves to provide products that show unexpected benefits or medical benefits, in addition to a balance of properties. Although the cotton fluff fibers and pulp of the present invention are described below mainly in association with the preparation of tissue paper products, the invention is thus not limited. The cotton lint fibers and inventive cotton lint paste prepared therefrom can be used to prepare other creped and non-creped nonwoven products, such as feminine sanitary products, other sanitary products, diaper liners and the like.

Preliminary medical studies comprising the use of the present inventive tissue paper product by individuals having certain inflammatory conditions suggest that the use of this product serves to improve such conditions in the majority of these tested individuals. In particular, a preliminary pilot study focusing on the use of the present invention by women affected by chronic and recurrent vulvar and vaginal infections and other inflammatory conditions has produced results that show a statistically significant improvement in such conditions with respect to fissure, infection secondary, pain and discharge.

A critical aspect of the present invention is the selection and identification of a viable grade (s) of the untreated cotton fluff fibers, in addition to the preparation of a viable cotton fluff pulp. As alluded to above, the physical characteristics of the untreated cotton fluff fibers and the resulting paste will determine the ability of the conventional tissue paper making equipment to process the material, in addition to the physical characteristics of the resulting sheet. .

The untreated cotton fluff fibers of the present invention have an average fiber length of from about 2 to about 16 mm and preferably comprise cotton swab of the second cut of America or Mexico or blends of the second Asian cotton fluff. and third cut. When mixtures of second and third cut Asian cotton fluff are employed, it is noted that mix proportions ranging from about 1: 4 to about 1: 1 (ie, from about 20% to about 50% by weight) are preferred. weight of second cuts and from approximately 80% to approximately 50% by weight of third cuts).

As used herein, the term "second cut cotton blot" means fibers removed from the cotton seeds during a second step of the cotton seeds through a shredder saw of a conventional shredder, while the term "erases" "Third cut cotton" means fibers removed from the cotton seeds during a third step of the cotton seeds through such a shredder saw.

The untreated cotton fluff fibers of the present invention generally exhibit the following physical characteristics: As suggested by the aforementioned physical characteristics, cotton lint made from cotton wool from the second American or Mexican cut produces silk paper with the best foil formation, the minority of pills and the minimum dirt content. In addition, this paste has the best handling characteristics in the equipment of the tissue paper factory.

In a more preferred embodiment of the present invention, the untreated cotton fluff fibers have an average fiber length of from about 2 to about 10 mm and preferably from about 4 to about 6 mm.

In still a more preferred embodiment, the untreated cotton fluff fibers have an average roughness measurement of from about 25 to about 70%, and more preferably from about 35 to about 55%. The term "roughness" as used herein means the equivalent percentage of the cell wall thickness ratio of the fiber divided by the sum of the cell wall thickness of the fiber and the diameter of the lumen. By way of explanation, cotton fluff fibers, which have a more circular-shaped lumen, typically exhibit a fiber diameter from about 0.7 to about 1.1 mils and a cell wall thickness from about 0.16 to about 0.40 mils.

It is noted here that the strength and opacity of the present inventive tissue paper products can be increased by using smaller amounts of fibers having average fiber lengths that fall outside the ranges mentioned above. In particular, the longer fibers of the second long cut and sawn wood cotton linters can be used to impart strength. However, such fibers must be too long or in an amount sufficient to cause the binding in the tissue paper factory equipment. In addition, shorter fibers, such as short second cut fibers, third cut fibers or shell fiber, can be used to fill gaps in the tissue paper sheet and thereby increase the opacity of the resulting sheet. . In a preferred embodiment, from about 48 to about 72% by weight of the longest cotton fibers of second American cut and from about 38 to about 52% by weight of shorter Asian fibers are used in conjunction with the fibers of untreated cotton linters described above.

The term "sawn wood", as used herein, means a mixture of cotton fluff fibers of first cut and second cut.The mixture can be obtained in a single pass of the seeds through a shredding machine by fixing the empty spaces of The blade of the saw shredder in such a way to eliminate both types of fibers Such a mixture can also be obtained by manually mixing the first cut cotton fluff with the second cut cotton fluff in a ratio of about 1: 4, respectively.

The term "skin fiber", as used herein, means very short fibers that are separated from the cotton seed husks by flapping the fiber-loaded shells in a defibrator.

The cationic starch derivative of the present invention is a naturally derived starch that has been chemically modified to impart a cationic part. The starch is preferably derived from corn or potatoes. In a preferred embodiment, the cationic starch derivative of the present invention is potato starch.

The starch subjected may be in granular form, pregelatinized granular form, or dispersed form. In a preferred embodiment, a 15 to 35% slurry of a potato starch derivative in water is employed. Suitable starches can be obtained from National Starch and Chemical Comapny, Bridgewater, New Jersey, under the trade names REDI-BOND 2038, 5330 and 5330a.

In a preferred embodiment, the cationic starch derivative is added to an aqueous fibrous slurry containing bleached, refined cotton lint paste in an amount ranging from about 0.1 to about 5.6% by weight, based on the total weight of the cotton lint at about 6% moisture content, and, more preferably, in an amount ranging from about 0.3 to about 1.3% by weight.

When the tissue paper product of the present invention is intended for use as a facial tissue paper, preferably from about 0.05 to about 3.0% by weight, and more preferably from about 0.1 to about 1.0% by weight of the tissue paper. a resistant resin in the wet state is also added to the aqueous fibrous slurry. A resistant resin in the preferred wet state can be obtained from Hercules Incorporated, Wilmington, DE 19894-0001 under the trade name Resistant Resin in the Wet State KYMENE 557H.

Other materials may be added to the aqueous fibrous slurry to promote ease of manufacture or to impart other characteristics or attributes to the tissue paper products, as they have no impact or adversely affect the softness and / or strength of the paper product. silk or its compatibility with individuals who have existing medical conditions or hypersensitivities.

The tissue paper products of the present invention can be prepared from single-ply or multilayer tissue paper fabrics and can take the form of single-ply tissue paper products or tissue paper products multi-layer In one embodiment, the inventive tissue paper product is a two-ply tissue paper product wherein each layer constitutes a single layer comprising: cotton fluff fibers having an average fiber length of from about 0.3 to about 3.0 mm; and an effective amount of a cationic starch.

In another embodiment, the inventive tissue paper product is a single layer tissue paper product comprising three contiguous layers, an inner or central layer comprising conventional wood pulp fibers and two outer layers, each comprising fibers of cotton lint, as described above, and having a caliper or thickness that ranges from about 0.06 to about 0.35 mm.

In yet another embodiment, the inventive tissue paper product is a two-ply tissue paper product wherein each layer constitutes a double layered sheet comprising a first layer made of cotton fluff fibers, as described above, and having a caliper or thickness from about 0.02 to about 0.50 mm, and a second layer made from conventional wood pulp fibers, and having a caliper or thickness from about 0.08 to about 0.80 mm. The sheets in double layers are bent with the layers of wood pulp fibers that are face to face with each other such that each layer of cotton fluff fibers constitutes an outer layer.

Preferred tissue paper products according to the present invention have a basis weight from about 1 to about 35 grams per square meter (g / m2) and, more preferably, from about 6 to about 30 g / m2. The density of the preferred tissue paper products is between about 0.02 and about 0.39 grams per cubic centimeter (g / cm3) and, most preferably between 0.08 and 0.29 g / cm3.

The tensile strength of the preferred tissue paper products is > 140 grams per inch (g / in) (> 55 grams per centimeter) for the tensile strength in the machinery direction (sheets of 2 sheets of wood, Tappi Method # 494) and, more preferably, from approximately 190 to 330 grams per inch (g / in). While square sheets (ie, tensile strength in the machine direction = tensile strength in the transverse direction) are contemplated by the present invention, it is preferred that the tensile strength in the transverse direction approximate at about 60 to about 70% of the tensile strength in the machine direction.

To prepare the tissue paper products of the present invention it is necessary first to prepare an aqueous fibrous slurry or pulp, which is described below.

PREPARATION OF A GROWTH OR AQUEOUS FIBROUS PASTA Initially, untreated cotton fluff fibers are mechanically cleaned to remove field debris, seed husks, cotton seeds and sand. Mechanical cleaning techniques are well known to those skilled in the art and include air separation techniques, where fibers are separated from debris as a result of density differences between these components, in addition to mechanical beating techniques. In a preferred embodiment, the untreated fibers are mechanically cleaned by a four stage mechanical beating system with air vapor transport and density separation steps between each stage. The mechanical cleaning takes place over a period of time ranging from about 1 to about 4 minutes until the volume of the higher density wastes have been separated from the lower density fibers.

Once the untreated fibers are mechanically cleaned, they are preferably saturated with a solution of sodium hydroxide and 1.8% refined resin oil to 5.6%. In particular, the untreated fibers are sprayed with the acoustic solution and then mechanically squeezed to remove the excess solution and to force the solution to penetrate the fibers, thereby adjusting the fiber to solution ratio. It is preferred that the fiber to solution ratio ranges from about 1: 3 to about 1: 5 Then the saturated fibers are transferred to a digester where they are heated by direct steam injection. The purpose of the digestion step is three times. First, cottonseed oils and waxes are made soluble in water by saponification to the sodium salts of fatty acids. Second, the fragments of seed and shell dissolve. Third, the viscosity or molecular weight of the cellulose is adjusted.

The strength of the acoustic solution, the ratio of fiber to solution or digester temperatures, pressures and cooking times are all factors that determine or control the gloss, dirt content, and strength of the cotton lint paper product. final. In particular, if the digestion process is too soft, the brightness of the resulting tissue paper product will be too low and the dirt content will be too large. Yes, on the other hand, the digestion process is too severe, the fibers will have reduced resistance. In a preferred embodiment, the saturated fibers are digested at temperatures ranging from about 140 ° C to about 195 ° C and at pressures ranging from about 0.28 MPa to about 1.24 MPa for a period of time ranging from about 25 minutes to about three hours . The digested cotton lint preferably has a viscosity ranging from about 50 to about 5, 000 seconds, and preferably, has a viscosity ranging from about 100 to about 1,000 seconds, as measured by the ACS Method published in the Industrial and Engineering Chemistry Analytical Edition. Vol. 1. Page 49. January 15. 1929. All the viscosity values cited in this document are the seconds required for the calibrated drop to fall 20 centimeters to a solution of 2.5 grams of cellulose dissolved in a solvent which has a composition of 165 grams of ammonia, 30 grams of copper, and 10 grams of sucrose.

In a more preferred embodiment, the saturated fibers are also subjected to an oxidation step in the digester. It is speculated that the lignin associated with the processing of cotton fluff originates with the seed shells and results in the formation of colored compounds when the cottonseed shells dissolve during digestion. It has been found that the addition of an oxidation step in the digester reduces the colored compounds and produces a brighter raw material. As will be readily apparent to those skilled in the art, such a step allows a reduction, if not elimination, of the amount of chlorine-based bleaching agents that would later need to be employed to produce an acceptable level of gloss in the resulting wood pulp.

The oxidation step mentioned above is preferably carried out by one of two methods. In the first method, hydrogen peroxide (H202) is used as a delignification agent and added to a solution of sodium hydroxide and 1.8% refined resin oil up to 5.6% to produce a H202 solution at 1 to 5% . The resulting peroxide solution is added to the cotton linters as they are loaded in the digester. Then the digestion takes place according to the process parameters described above. The good bleaching action of peroxide is facilitated by good mixing and high temperature of digestion. It is noted that such a method results in some decomposition of the peroxide, which has an impact on the efficiency of this method.

In the second method, oxygen is used as the delignification agent. In particular, oxygen, in an amount ranging from about 0.11 to about 0.78 MPa per metric ton of untreated fiber. It is added to the digester before heating with steam or at the end of the digester cycle. As will be readily apparent to those skilled in the art, the amount of oxygen added will be dependent on the pressure limitation of the digester and the vapor pressure that is used to cook the cotton linters.

In an even more preferred embodiment, oxygen is used as the delignification agent and is added to the digester before steam heating. It has also been found that oxygen, in combination with the acoustic solution and high temperature used during digestion, reduces the viscosity of cellulose to a greater degree than digestion with only the acoustic solution at high temperatures. As a result, a reduction of 20 to 28% in the vapor pressure and therefore in the temperature during the digestion cycle can be realized, thereby increasing the efficiency of the overall digestion process.

As a final step before transferring the untreated cotton lint digested from the digester, it is preferred that the carbon dioxide is used as a neutralizing agent for the residual acoustic solution. The use of carbon dioxide plays a role in the production of a wood pulp with a low ash content. As will be readily apparent, the resulting calcium content can be reduced by washing the digested fluff with deionized water to remove the bicarbonate salt formed by means of the neutralization reaction.

Once the untreated cotton fluff fibers have been digested, the resulting wood pulp is transferred to a bleaching system. The bleaching can be carried out according to the bleaching technique using reduced amounts of elemental chlorine. It is preferred that such conventional techniques are carried out to effect a viscosity decrease in the range from about 30 to about 55%. The decreases within this range result in a high gloss wood pulp with minor reductions in the strength of wood pulp.

In a preferred embodiment, the use of elemental chlorine is eliminated. In particular, a Sodium chlorite and sodium hypochlorite mixture having a pH from about 2.0 to about 4.5 is added to the digested fibers or pulp in an amount of from about 4 to about 12 kilograms of sodium chlorite per metric ton fiber. Then the temperature in the bleaching system or device is raised to about 48 to about 60 ° C and that temperature is maintained for about 35 to about 55 minutes. It is observed that this combination of chemical products produces chlorine dioxide which becomes the primary bleaching agent.

Then, the hydrogen peroxide, in amounts qee ranging from about 0.4 to about 1.4 percent by weight in wood pulp, is added to the aforementioned bleach liquor or bleach to put back the bleaching with hypochlorite in the second stage. A buffer for pH control (eg, sodium silicate-sodium hydroxide solution) in amounts ranging from about 0.1 to about 0.7 percent by weight in paste is also added to the bleaching liquor, as well as, sequestering agents (e.g., magnesium sulfate) in amounts ranging from about 0.1 to about 0.3 percent by weight in pulp. Then the temperature in the bleaching device is raised from about 74 to about 88 ° C and that temperature is maintained from about 45 to about 70 minutes. In a preferred embodiment, the solids% of the bleach liquor ranges from about 12 to about 19% by weight of solids.

Finally, the wood pulp is acidified to a pH from about 2.5 to about 3.5 to reduce the ash content. Alternatively, from about 2 to about 5 kilograms of a 3: 1 mixture of sodium chlorite and sodium hypochlorite is added to bleached wood pulp to effect such a reduction in the ash content. Preferably, the ash content is reduced to a level from about 0.05 to about 0.65 percent by weight of dry wood pulp.

In a more preferred embodiment, the bleaching is carried out with chlorine-free chemicals. In particular, hydrogen peroxide is added to the digested fibers or pulp in an amount of about 35 to about 90 kilograms of peroxide per metric ton of fiber. The temperature in the bleaching device is raised to about 71 to about 88 ° C and that temperature is maintained for about 50 to about 90 minutes. The bleaching step with peroxide can be repeated if necessary to achieve the desired amount of gloss. Once the desired level of gloss is achieved, the fibers are washed in acidic water having a pH from about 3 to about 5 for the purpose of removing the bleaching chemicals.

Surprisingly, cotton linters produced with oxygen treatment during digestion and bleached with hydrogen peroxide have gloss values, which are equivalent to cotton lint pastes produced by conventional bleaching techniques. In addition, the pulps produced with oxygen and peroxide are stronger than the pastes of equal brightness produced by conventional bleaching techniques. Once the pulp is bleached, it is transferred to a refining device, where the fibers are cut and fibrillated.

The amount and type of refining has a significant, if not critical, impact on the quality of the finished product. It has been found that prolonged, gradual refining by, for example, a Hollander type beater, provides a refined paste that is processable by domestic tissue paper factories. In a preferred embodiment, the fibers are refined for a period of from about 2 to about 3 hours in a Hollander type beater until an average fiber length of about 0.3 to about 3.0 mm is obtained.

After refining, an effective amount of a cationic starch derivative and other components, if desired, are added to the refined pasta.

PREPARATION OF A SILK PAPER TISSUE In a non-integrated system (ie, where the pulp mill is unrelated to the tissue paper factory), bleached and refined pulp fibers are formed into a pulp sheet and delivered to the tissue paper factory . In an integrated system (i.e., where the pulp mill is connected to the tissue paper mill), bleached and refined pulp fibers, in the form of an aqueous fibrous slurry, are typically delivered through a line of tubing from the bleaching / refining area of the pulp mill to the tissue paper factory.

It is noted that the raw material slurry pumps which are employed in the tissue paper mills for the purpose of moving the aqueous fibrous slurries from one processing point to another are typically equipped with multi-bladed, open-face impellers, such as as a type 2-4, and are operated at a low RPM (ie <1,800). It is also observed that pumps operated at higher speeds and with 5-blade and 6-blade impellers will be plugged when exposed to aqueous cotton fluff slurries. It has been discovered and therefore it is preferred, that the raw material slurry pumps employed in the practice of the present invention comprise low speed (ie 880 to 1,200 RPM), high volume pumps with large headroom (ie. say, 4.4 to 7.6 centimeters) between the blades.

Once the bleached and refined pulp fibers are received into the tissue paper factory they are mechanically reduced to pulp for the purpose of fiber separation. In a preferred embodiment, an aqueous cotton lint slurry of 3.0 to approximately 4.2% is mechanically converted to paste at room temperature for a minimum of 60 minutes in a system capable of effecting a stirring pattern which serves to prevent empty dead spaces underneath of the surface of the slurry and the flotation of the raw material not stirred on the surface of the slurry. In a more preferred embodiment, an aqueous cotton lint slurry at 3.4 to about 4.4% is mechanically converted as described above at a temperature ranging from about 49 to about 57 ° C for a minimum of 40 minutes.

Then the fibers mechanically converted to pulp are subjected to either one or two refining step, whereby the fibers are preferably refined to a Canadian Standard Drain Freedom of 400 to 680 milliliters.

For tissue paper mills that are equipped with only a double disc refiner, it is preferred that the refiner used here be of adequate size to deliver 4.5 to 6.0 horsepower applied net per day per ton of processed fibers ("HPD / Net T "). By way of explanation, a double-disk refiner has two sets of two superimposed refining plates that form two interfaces. Each set of refining plates has a rotatable plate and a fixed plate, the distance between each set of plates is adjustable. As is well known to those skilled in the art, a fiber slurry is pumped through each interface, where the fibers are cut and refined by the cutting surface of each refining plate. Since the refining plates move closer together, more fibers are cut and refined and more energy is applied to the fiber. The term "net applied horsepower" is a measure of the energy applied to the fiber, and as used here, it means the difference between available horsepower and "unloaded horsepower" or the number of horses force necessary to operate the plates when the distance or free space between the plates is too large since no refining takes place. As a general rule, the "net applied horsepower" is equal to approximately 80 to 85% of the available horsepower. For example, a refiner equipped with a 600 horsepower engine could deliver 480 to 510 horsepower net applied. Therefore, if a tissue paper manufacturing machine of the tissue paper factory operates at 3.0 tons per hour or 72 tons per day, the net HPD / T would be between 6.67 and 7.08.

For the tissue paper mills that are equipped with two refiners, it is preferred that the refiners be placed in series and that a first refiner be equipped with plates that serve to provide greater cutting and fibrillation. Such plates have slightly larger openings between the barriers, in comparison to the plates that provide more fibrillation than cut, and therefore are less subject to plugging with cotton fluff fibers. This type of plate is available from J & amp;; L Machine Company, Waukesha, Wisconsin, under the product name model 24-EJ 109/110 and model 24-EJ 127/128. It is further preferred that a second refiner be equipped with plates that provide slightly more fibrillation than the plates used in the first refiner. Such plates are available from J &L Machine Company under the product names model 24-101 / 102 and model 24-EJ 103/104. As will be readily apparent, having two refiners in series, the degree of cutting and fibrillation can be adjusted to manipulate a range of the fiber blends.

In another preferred embodiment, a refiner with a double disc configuration is used, which allows the raw material to flow through a first interface and then through a second interface. As will be readily apparent, such a configuration allows one type of plate to be used to form the first interface and a second type of plate to form the second interface.

In a more preferred embodiment, two raw material preparation systems are used, with each system having a dedicated refiner. Such an arrangement allows different types of cotton lint paste to be treated or processed separately and then mixed as it is contrary to first mixing the fibers and then cutting and fibrillating the mixed raw material.

Once the fibers are refined, the aqueous slurry containing the refined fibers is diluted with recycled water until a fiber concentration of about 0.1 to about 0.4% is achieved. Then the diluted slurry is routed through the pressure screens having slots measuring from about 1.0 to about mm and / or holes measuring from about 1.0 to about 2.4 mm. The slurry is then directed to a main box of a papermaking machine, where it is mixed thoroughly to provide a homogeneous slurry before being deposited in a shaping wire or cylinder. The deposited slurry is then progressively dehydrated to approximately 30% solids by gravity, vacuum aided drainage and mechanical pressing and then secured to a cylindrical surface of a Yankee desiccator heated with steam aided by an applied adhesive. The desiccation is completed in the Yankee desiccator. Then the resulting dry fabric is "creped" by means of the Yankee desiccator by a doctor or the creped blade is positioned at an angle from about 8 to about 30 ° relative to the surface of the desiccator and then rolled into a roll.

For embodiments wherein the inventive tissue paper product is a product of two sheets of wood (e.g., where each sheet of wood constitutes a single layer comprising cotton fluff fibers and cationic starch or starch derivative), and / or for embodiments wherein the inventive tissue paper product is a tissue paper product of a wood sheet comprising three contiguous layers (e.g., an inner or central layer comprising conventional wood pulp fibers and a main case) The double layer can be used to take into account the processing according to the specifications of each layer.In addition, two raw material preparation systems and a single layer main box can also be used to take into account two types of raw material they can be subsequently measured in single layers in different proportions.

Referring now to the drawings in detail, the scanning electron micrographs of the present facial tissue and bath tissue products are shown along with scanning electron micrographs of CHARMIN and COTTONELLE bath tissue papers and tissue paper KLEENEX facial Figures 1 to 5 show the marked differences in fiber orientation and structure between the cotton fluff fiber tissue paper products of the present invention and the wood fiber tissue paper products of the prior art. In particular, the fibers shown in Figures 1 and 4 have a smooth "ribbon-like" structure and show a greater degree of fibrillation. These fibers are arranged in more regular coils than the more disorganized wood pulp fibers of the prior art tissue paper products and appear more flexible suggesting greater fiber to fiber contact and better bonding. In marked contrast, Figures 2, 3 and 5 show wood fibers that tend to remain more upright and stiffer, are less "treatable" when placed in contact with other fibers and show a lower degree of fibrillation.

SPECIFIC EXAMPLES EXAMPLE NO.

A pilot study was attempted for the purpose of determining whether the use of the present inventive tissue paper product (as compared to conventional wood-based tissue paper products) by women who have recently experienced normal vaginal deliveries would serve to reduce irritation perineal after the perineal restoration. The irritation or perineal discomfort that results from the perineal restoration is common after a vaginal delivery. Suturing correct episiotomies or perineal tears may help reduce discomfort, but other factors may be important.

In the submitted study, a hundred women who had a normal vaginal delivery with perineal restoration (either a tear or a second degree eipiotomy) at Queen Charlotte's and Chelsea Hospital in London, England, were reclusted during the months of August to December 1996. Women with a tear of the first or third degree or a history of perineal problems were excluded. Women were recruited on the first day of postpartum with informed written consent. The random selection was by computer generated random numbers and each participant was given 10 rolls of either the present inventive tissue paper product or a conventional tissue based tissue paper product in sealed packages marked A (48 women) or B (52 women), respectively. Both the investigators and the subjects were blinded to the type of tissue paper distributed and the identities of tissues A and B were not revealed until after the results had been analyzed.

A survey was completed 24 hours post-delivery with a visual analog classification (scale 0-100 millimeters) to assess the perineal pain. A second postal survey was sent to each woman eight weeks after birth. Again a visual analogue classification was used to assess the perineal discomfort, and the researchers asked questions regarding perineal itching and swelling, resumption of intercourse, bowel habits and breastfeeding.

The researchers received 92 completed surveys, 46 from Group A and 46 from Group B. The results were analyzed by the Chi2 tests for comparable data, and t tests for the average pain scores. The results are shown in Table 1 below: Table 1 Summary of Pilot Study Results Participants of Group B Value P Pilot Study (n = 46) (n = 46) No. with episiotomy 9 (20%) 18 (39%) 0.04 No. with tear of 37 (80%) 28 (61%) 0.04 second degree 8 Weeks No. with perineal pain 4 (9%) 7 (15%) 0.41 No. with perineal itching 4 (9%) 11 (24%) 0.048 No. with perineal swelling 1 (2%) 4 (9%) 0.80 No. still breastfeeding 34 (74%) 32 (70%) 0.64 No. sexual intercourse resumed 20 (43%) 28 (61%) 0.10 No. with pain in the ratio 3 (15%) 7 (25í 0.40 There were no significant differences between the two groups of women in terms of average birth weights, parity, or incidence of bleeding, 24 hours after delivery.

There were more episiotomies significantly carried out in Group B than in Group A, but there were no differences in the suture material or technique used, and comparable numbers were sutured by midwives and doctors.

Similar numbers in each group complained of constipation, never had milk production or were still producing milk in eight months, and had sexual intercourse resumed. There were no significant differences between the two groups in mean perineal pain scores at 24 hours after birth, and no difference in the improvement of perineal pain or swelling ratings. Few women who use the inventive tissue paper product complained of perineal pain or swelling in eight months. There were few women significantly with perineal itching in eight months in those who have used the inventive tissue paper product, 4 out of 46 (9%), compared to 11 out of 46 (24%) in those who have used the paper product based on wood (P <0.05).

This study suggests that the use of the present inventive tissue paper product can reduce perineal irritation as shown by less pain, itching, swelling at eight months after the perineal restoration resulting from normal vaginal delivery.

EXAMPLE NO. 2 Absorbency tests 1. Hydrophilicity The hydrophilicity of a tissue paper product refers to the propensity of the tissue paper product to be moistened with water. The absorbency or hydrophilicity can be quantified by determining the amount of water absorbed by the tissue paper samples within fixed time periods and determining the total time required for each sample to achieve maximum absorbency.

For the present examples, the procedure detailed in ASTM code D5801-95 was used to determine the absorbent capacity of: the present facial and bath tissue products; bath tissue papers CHARMIN and COTTONELLE; and PUFFS and KLEENEX facial tissue papers.

The samples were placed in separate horizontal test plates, such that a lower surface supported on the plate and an upper surface was covered by the test weight. Each test plate was connected to a separate liquid reservoir by a siphon tube. Each liquid deposit was placed on an electronic balance. The liquid was absorbed in the sample. The resulting reduction in the liquid present in the deposit was measured by the balance and recorded by a connected computer.

The test conditions described in this procedure include a negative liquid height. The surface of the liquid in the reservoir was below the lower surface of the sample in contact with the test plate.

For the submitted evaluation, five sample sheets measuring 50 + 1 mm in diameter are provided for each tissue paper sample that was tested. The liquid reservoir, which contains approximately 200 ml of water, was placed in the electronic balance. A 60 ml syringe was attached to the end of the tube connected to the reservoir, and was used to pull the water up to the tube until it was filled. Then the tube was connected to a hose tab on a 50 mm diameter test plate placed on a platform and the balance was tared. A sample was placed on the plate and a weight of 50 grams was placed on top of the sample to ensure even contact between the sample and the liquid.

The platform was adjusted until the water in the tube made contact with the sample. The negative liquid height was maintained by having the sample approximately 4 mm below the surface of the water in the liquid reservoir. The balance and the computer were set to record the weight of the water in the liquid reservoir every three seconds. The sample was allowed to absorb water until the rate of absorption was less than 0.01 grams per 15 seconds at which point the sample was assumed to be saturated.

The amount of water absorbed according to the electronic balance was recorded by the computer. The saturated sample was removed. The test plate was dried and the liquid reservoir refilled. The procedure was repeated on the remaining four sample sheets and the results were averaged. Then the procedure was repeated in the remaining test samples.

The results of the absorbency or hydrophilicity test mentioned above are tabulated in Table 2 below: Table 2 Water Weight (g) Absorbed in 3 seconds 9 seconds SAMPLES Silk Paper For Bath Present invention 0.51 1.01 CHARMIN 0.05 0.84 COTTONELLE 0.06 0.72 Facial Silk Paper Present invention 0.06 0.71 PUFFS 0.07 0.40 KLEENEX 0.02 0.62 The results of the absorbency or hydrophilicity test detailed in Table 2 show that the present facial tissue and bath tissue products have a greater propensity to be moistened compared to commercial facial and bath tissue papers of the art. previous. 2. Bacteria Absorbance Test. to. Staphylococcus Aureus For this test, the procedure mentioned above (ie, ASTM D5801-95) was repeated using staphylococcus aureus bacteria ATCC # 6538 as the liquid test solution.

The results - of the aforeus staphylococcus aureus bacteria absorbency test mentioned above are tabulated in Table 3 below: Table 3 Liquid Test Solution of Staphylococcus Aureus (g) Absorbed in 3 seconds 6 seconds SAMPLES Silk Paper For Bath Present invention 0.44 0.93 CHARMIN 0.07 0.74 COTTONELLE 0.07 0.61 Facial Silk Paper Present invention 0.19 0.79 PUFFS 0.05 0.15 KLEENEX 0.06 0.42 Consistent with the results of the hydrophilicity test detailed above, the results of the staphylococcus aureau bacteria absorbency test detailed in Table 3 show that the present inventive facial and bath tissue tissue products absorb considerably greater amounts of bacteria from staphylococcus aureus compared to commercial facial and bath tissue papers of the prior art. b. Candida Albicans For this test, the procedure mentioned above (ie, ASTM D5801-95) was repeated using candida albicans bacteria ATCC # 10231 as the liquid test solution The results of the bacterial absorbance test of candida albicans mentioned above are tabulated in Table 4 below: Table 4 Liquid Test Solution of Candida Albicans (g) Absorbed in 3 seconds 6 seconds 9 seconds SAMPLES Silk Paper For bathroom Present invention 0.19 0. 84 0. 97 CHARMIN 0.42 0. 81 0. 91 COTTONELLE 0.08 0. 61 0. 83 Facial Silk Paper Present invention 0.37 0.82 0.93 PUFFS 0.05 0.15 0.34 KLEENEX 0.08 0.45 0.67 The results of the Candida albicans Absorbency test detailed in Table 4 show that the inventive facial tissue paper absorbs considerably larger amounts of candida albicans bacteria compared to the PUFFS and KLEENEX facial silk papers. In addition, the inventive bath tissue product absorbs more candida albicans bacteria than COTTONELLE bath tissue. It is noted that although CHARMIN bath tissue works best in the three second test, the present inventive bath tissue product exceeds CHARMIN and COTTONELLE in the 6 and 9 second tests. '5 3. Urine Absorbance Test For this test, the aforementioned procedure (ie, ASTM D5801-95) was repeated using synthetic urine as the liquid test solution.

The results of the urine absorbency test mentioned above are tabulated in Table 5 below. fifteen 0 Table 5 Urine (g) Absorbed in 3 seconds SAMPLES Silk Paper For bathroom Present invention 0.46 CHARMIN 0.36 COTTONELLE 0.03 Facial Silk Paper Present invention 0.46 PUFFS 0.04 KLEENEX 0.07 The results of the water absorbency test detailed in Table 5 show that inventive facial and bath tissue products absorb larger amounts of urine compared to commercial bathing and facial tissue papers of the prior art.

EXAMPLE NO. 3 Abrasion Test For the present example, the following test procedure was used to determine the level of surface abrasion on a polycarbonate lens produced by: the tissue and facial tissue products of the present invention; bathroom tissue paper CHARMIN; and KLEENEX facial tissue paper. For this procedure, twelve sample sheets measuring 21.75 cm x 21.3 cm were provided for each tissue paper sample being tested. Each sample sheet was folded in half and then folded in half again and the folded sheet was placed on a pad located in a mechanical abrasion device. The mechanical abrasion device was digitized to complete a specific number of cycles in a given period. Then an uncoated polycarbonate lens was measured by mist using a BKY Gadner Plus Haze Percent Meter and then fixedly attached to the abrasion device. The pad on which the folded sheet was placed was placed in contact with the lens at a specific pressure, simulating better the normal sweep pressure. Then the folded sheet was rubbed against the lens for a total of 1200 cycles. Then the lens was measured again by haze. The mist measurements taken before and after the abrasion were subtracted from each other. The procedure was repeated for the eleven remaining sample sheets and then the average surface abrasion level or increase in the haze measurements for the eleven sample sheets was calculated. Then the aforementioned procedure was repeated for the remaining tissue paper products.

The results are tabulated in Table 6 below.

Table 6 Increase in Haze (after 1200 cycles) SAMPLE NO.

Sample 10 11 12 The results of the surface abrasion level test detailed in Table 6 show that the present bath tissue and inventive facial tissue products are less abrasive than the tissue paper and facial tissue products of the prior art tested.

EXAMPLE NO. 4 Dirt and Cleaning Tests For the present example, the following procedure was used to determine the level of soil and dirt removal from the surface of a hard resin lens effected by: the tissue and facial tissue products of the present invention; bath tissue papers CHARMIN AND COTTONELLE; and PUFFS and KLEENEX facial tissue papers. For this procedure, the dirt and oil was placed on a hard resin lens in a specific manner, so that the same amount and site were repeatable precisely for each lens used during the test. A different lens and a tissue paper sample were used each time. The machine used for this test allowed the tissue paper to come into contact with the lens at a predetermined pressure for 5 cycles. The lens, with the dirt and soil dispersion in it, was initially measured by mist using a BKY Gadner Plus Burn Level Meter. Then the lens was fixed to the machine for the completion of 5 cycles. Then the lens was removed from the machine and measured by mist. Then the lens was placed in a machine for another 5 cycles. This procedure was repeated for a total of 60 cycles.

In accordance with the above, thirty-six sample sheets measuring 21.75 cm x 21.3 cm were provided for each tissue paper sample being tested. Then the folded sheet was tested as described above.

The results are tabulated in table 7 below.

Table 7 Increase in Mist (after 60 cycles SAMPLE NO.

Sample 10 11 12 The soil and dirt level test results detailed in Table 7 show that the present bath tissue and inventive facial tissue products are much better at removing dirt and soil from the surface of a hard resin lens than the bath tissue and facial tissue products of the prior art.

EXAMPLE NO. 5 Dry Lint Formation Tests In accordance with the procedures detailed in IES-RP-CC-003-87-T, ASTM F51-68 (89) (El) and ASTM F50-96, the degree of dry lint formation shown by the present products was determined. Facial and bathroom tissue paper, CHARMIN and COTTONELLE bath tissue products and PUFFS facial tissue product.

Sample tissue paper products were tested by placing the sample in a chamber of a stainless steel drum measuring approximately 43 cm in diameter and 33 cm in width, which is capable of being rotated at 10 revolutions per minute (RPM) . The clamps are located inside the chamber.

The rotating drum along with a drive unit is placed in a class 100 laminar flow smoke hood. An air sampling tube was placed inside the drum chamber to draw air out of the chamber. An open end of a collection tube was adjusted to be within 24.3 mm of the clamps within the chamber and is located approximately in the center.

The air sampling tube was connected to a laser particle counter that used a length of 4-5 feet of flexible tubing. The laser particle counter was allowed to warm up for a minimum of 15 minutes before the test.

The density of the particle inside the rotary chamber under vacuum was determined during three one-minute intervals. The acceptable background counts were < 100 particles (> 0.5 μm) / minute. The chamber was allowed to spin until acceptable counts were obtained. The cleaning of the interior of the chamber was carried out using isopropyl alcohol and cloths for clean room with low lint formation. When the counts of the background particle density were acceptable, the test items were placed in the rotating chamber and the counts were collected for 10 minutes.

A blank control was determined for the rotating camera by conducting three one-minute counts with no test material in the chamber. The average of three-minute blank counts was subtracted from the counts of the test sample.

The test apparatus was held in a stationary position within the clean HEPA filter bank. The test sample was carefully removed from its protective packing and placed in the rotating chamber. The driving unit and particle counter were put into operation immediately and a chronometer was adjusted for 10 minutes. The number of particles / minute > 5μm were reported after subtracting the blank control. In addition to being tested as a complete sample, each sample was also tested after it broke in half.

The results obtained according to the aforementioned test are tabulated in Table 8 below.

Table 8 Particle Count SAMPLE NO. Sample 10 11 12 The results of the dry lint-forming test detailed in Table 8 show that the present invention deposits or generates considerably less waste of lint particles compared to the prior art tissue paper products tested.

EXAMPLE NO. 6 Facial Cutaneous Irritation Test For the present example, the following procedure was used to determine the degree of abrasion on the facial skin caused or generated by the present inventive facial tissue product and by the KLEENEX and PUFFS facial tissue products. For this test or study, which is conducted by The California Skin Research Institute (CSRI), San Diego, CA, sixty-three test subjects participated in a three-day "crawl" period using padded facial squares and towels of anogenital toilet available TUCKS. On the first day, visual facial assessments with baseline were carried out on each test subject. The D-SQUAME plastic films (CuDerm Corporation, Dallas, TX) were fixed to the right and left cheeks and the right and left sides of each test subject by pressing the plastic film firmly against the skin for 15 seconds. Then the plastic films were removed and fixed to the blank areas contained in reference cards that are designed to provide indications of semiquantitative levels of skin peeling. These plastic films serve as a baseline for the desquamation of corneocytes. Following the removal of the D-SQUAME plastic films, a sheet of a sample tissue paper product was mechanically rubbed (turbulent action) on the left and right side of the face (middle line) of each test subject for 30 seconds by a specialist. Then the side against side of the face of each test subject was rubbed mechanically (turbulent action) for 30 seconds by the specialist. After 15 minutes, parts of the D-SQUAME plastic film were firmly pressed against the skin in both the treatment of the each of each test subject for 15 seconds. Then the D-SQUAME plastic films were removed and fixed to the blank areas contained in the reference cards mentioned above. Increasing levels of desquamation were indicated by the presence or visual absence of skin scales. The presence of increasing levels of skin scales indicates larger desquamation (ie, moderate microabrasion for the skin).

After one hour of rest, the mechanical rubbing procedure of 30 seconds with the sample tissue paper products was repeated, along with a 15 minute rest, and the application of the D-SQUAME plastic films. Following a rest period of one additional hour, the sampling of the mechanical process and desquamation is presented as a final treatment and the results are tabulated. A final visual evaluation of the face of each test subject was carried out following the three treatments. Visual evaluation was performed using a four-point clinical scale to measure erythema, edema, papules, and skin vesicles (by North American Contact Dermatitis Group).

A greater degree of reduction in desquamation was an indication of a lower level of abrasiveness. The results of the facial skin irritation test mentioned above are tabulated in Table 9 below.

Table 9 SAMPLES Reduction in the Degree of Facial Silk Paper Descamación (%) Present invention 64 KLEENEX 36 PUFFS 36 The test results detailed in Table 9 show that the KLEENEX and PUFFS facial tissue products are almost twice as irritating to facial skin as the facial tissue paper product of the present invention.

EXAMPLE NO.

Microscopic Ultrastructural Damage to Normal Skin Electron microscopic ultrastructural changes to normal skin as a result of five days of controlled use of either the facial tissue paper product of the present invention, KLEENEX facial tissue paper or PUFFS PLUS facial tissue paper, were evaluated. For this evaluation, which is also carried out by CSRI, twenty test subjects initially participated in a three-day "drag" period using NEUTROGENA glycerin soap and a facial tissue paper provided by CSRI to ensure that the Facial skin of all test subjects was treated essentially under the same clinical conditions before the start of the study. On the first day of study (baselin), subjects received visual clinical evaluations. In addition, the Chromameter readings (Minolta CR300) were carried out in the right and left perauricular region of the ear, forehead, chin and cheeks of each test subject with an 8 mm microprobe aperture. The Chromameter provides objective evidence of clinical and subclinical erythema (redness) based on refractive index readings that shed skin and detected by the instrument. On the first day and for the next four days, each test subject uses either the present inventive facial tissue paper product, KLEENEX tissue paper or PUFFS PLUS tissue paper and completes a daily documentation for the use of the test samples. All test subjects were blinded to the type or class of facial tissue paper received in accordance with this study. On the sixth day of the study, a 2 mm punch biopsy of the facial area of each test subject was obtained and the electronic micrographs of these tissue paper samples were taken for the purpose of showing the ultrastructural changes for the stratum cutaneous layer. corneal as a result of the five days of controlled use of the respective test samples. The electron micrograph showing a skin sample with petrolatum and skin samples of the representative test subjects after the use of one of the aforementioned tissue paper products was presented in Figures 6, 7, 8, and 9, respectively .

The separation of medium tissue paper that results from the five days of controlled use of the respective test samples was determined by measuring the distance of the uppermost separation region from the epidermis to the stratum corneum as shown in the electron micrograph. submitted. This was determined using a monogram designed primarily to determine the size and distance of an object from its electron microscopic image (J. Submicrosc, Cytol, 13, 95, 1981). The results are mentioned in Table 10 below.

Table 10 SAMPLES Separation of Silk Paper A ° Medium Facial Silk Paper Present Invention 20 KLEENEX 212 PUFFS PLUS 120 The test results detailed in Table 10 and shown in Figures 6 through 9 show The significantly less detrimental effect of the present invention on normal skin compared to paper KLEENEX silk and PUFFS PLUS. The fact that the stratum corneum skin layer is allowed to interact after the use of the present inventive tissue paper product in comparison to the observed separation of this cutaneous layer caused from the use of the aforementioned tissue paper products above is dramatic evidence of the damage and less abrasive nature of the present invention.

Although this invention has been shown and described, with respect to the detailed embodiments thereof, it will be understood by those skilled in the art that various changes in the form and detail thereof may be made without departing from the spirit of the claimed invention.

It is noted that in relation to this date, the best method known to the applicant to carry out the invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (26)

1. A product of soft, glossy and resistant tissue paper, characterized in that the product is prepared from untreated cotton fluff fibers having an average fiber length from about 2 to about 16 millimeters and comprises: cotton fluff fibers which have an average fiber length from about 0.3 to about 3.0 millimeters and an effective amount of a cationic starch derivative.

2. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the untreated cotton fluff fibers are second cut cotton fluff fibers having an average fiber length of from about 3 to about 5. millimeters, and a content of dirt and seed fragments of < 12% by weight and a residual fiber content and juniper liquor speck of < 3% by weight.

3. The product of soft, glossy and resistant tissue paper according to claim 1, characterized in that the cotton fluff fibers comprise a mixture of cotton fluff fibers of second and third cut, wherein the mixture comprises: second cut cotton fluff fibers having an average fiber length of from about 3 to about 6 millimeters, a dirt and seed fragment content of < 14% by weight and a residual content of classified fiber and speck of juniper liquor = 5% by weight; Y third cut cotton fluff fibers free from remnants of classified fiber and juniper liquor speck having an average fiber length from about 2 to about 3 millimeters and a content of dirt and seed fragments of < 16% by weight.

4. The product of soft, glossy and resistant tissue paper according to claim 3, characterized in that the mixture comprises from about 20 to about 50% by weight cottonseed fibers of second cut and from about 80 to about 50% by weight. Weight of cotton fibers of third cut.

5. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the untreated cotton fluff fibers have an average fiber length from about 2 to about 10 millimeters.

6. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the untreated cotton fluff fibers have an average fiber length from about 4 to about 6 millimeters.

7. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the untreated cotton fluff fibers have an average roughness measure from about 25 to about 70%.

8. The product of soft, glossy and resistant tissue paper according to claim 1, characterized in that the untreated cotton fluff fibers have an average roughness measure from about 35 to about 55%.

9. The product of soft, glossy and resistant tissue paper according to claim 1, characterized in that the cationic starch derivative is a starch derived from corn or potatoes that has been chemically modified to impart a cationic part.

10. The product of soft, glossy and resistant tissue paper according to claim 9, characterized in that the cationic starch derivative is potato starch.

11. The product of soft, glossy and resistant tissue paper according to claim 1, characterized in that the tissue paper product is a facial tissue paper product that also comprises from about 0.05 to about 3.0% by weight of a resistant resin in the wet state.

12. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the tissue paper product is a tissue paper product of two sheets of wood, wherein each sheet of wood is a single layer that it comprises cotton fluff fibers having an average fiber length from about 0.3 to about 3.0 millimeters and an effective amount of a cationic starch derivative.

13. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the tissue paper product has a basis weight from about 1 to about 35 grams per square meter, a density of between about 0.02 and about 0.39. grams per cubic centimeter, a tensile strength in the direction of the > 140 grams per inch (> 55 grams per centimeter) and a tensile strength in the transverse direction from about 60 to about 70% of the tensile strength in the machine direction.

14. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the tissue paper product is a tissue paper product of a wood sheet comprising: a first and a second outer layer prepared to from untreated cotton fluff fibers having an average fiber length of from about 2 to about 16 millimeters and comprising cotton fluff fibers having an average fiber length of from about 0.3 to about 3.0 millimeters and an effective amount of a cationic starch derivative; and an inner layer located between the first and second outer layers comprising wood fibers, wherein the first and second outer layers each have a caliper or thickness ranging from about 0.06 to about 0.35 millimeters.

15. The soft, glossy and resistant tissue paper product according to claim 1, characterized in that the tissue paper product is a two-ply wood tissue paper product, wherein each wood sheet is a layered sheet double comprising: a first layer having a caliper or thickness from about 0.02 to about 0.50 millimeters which is prepared from untreated cotton fluff fibers having an average fiber length from about 2 to about 16 millimeters and comprising cotton fluff fibers having an average fiber length of from about 0.3 to about 3.0 millimeters and an effective amount of a cationic starch derivative; and a second layer having a caliper or thickness from about 0.08 to about 0.80 millimeters comprising wood fibers, and wherein the second layers of the sheets in double layers are placed between the first layers in the tissue paper product of two sheets of wood.

16. A process for preparing a soft, glossy and resistant tissue paper product characterized in that the process comprises: selecting untreated cotton fluff fibers having an average fiber length of from about 2 to about 16 millimeters or mixtures thereof; mechanically clean the selected fibers; digest mechanically cleaned fibers to form a wood pulp; whiten wood pulp; whisk or refine bleached wood pulp until an average fiber length of about 0.3 to about 3.0 millimeters is achieved; Y form the bleached and refined wood pulp on a sheet.

17. The process according to claim 16, characterized in that the bleached wood pulp is subjected to prolonged, gradual refining by means of a Hollander-type beater for a period from about 2 to about 3 hours until an average fiber length of about 0.3 is obtained. up to approximately 3.0 millimeters.

18. The process according to claim 16, characterized in that the process also comprises: saturate the mechanically cleaned fibers with a 1.8 to 5.6% acoustic solution comprising sodium hydroxide and refined resin oil; and mechanically pressing the saturated fibers to achieve a fiber to acoustic solution ratio ranging from about 1: 3 to about 1: 5.

19. The process according to claim 18, characterized in that the acoustic solution further comprises a delignification agent comprising hydrogen peroxide.

20. The process according to claim 16 or 18, characterized in that the mechanically cleaned fibers are digested in the presence of oxygen gas, wherein the oxygen gas is present in an amount ranging from about 0.11 to about 0.78 MPa per metric ton of fiber.

21. The process according to claim 16, characterized in that the mechanically cleaned fibers are digested at temperatures ranging from about 140 ° to about 195 ° C and at pressures ranging from about 0.28 to about 1.24 MPa for a period of time ranging from about 25 minutes to approximately 3 hours.

22. The process according to claim 21, characterized in that the digested fibers or wood pulp have a viscosity ranging from about 50 to 5,000 seconds.

23. The process according to claim 18, characterized in that the process further comprises: neutralizing the wood pulp with carbon dioxide before bleaching.

24. The process according to claim 16, characterized in that the wood pulp is bleached by adding a mixture of sodium chlorite and sodium hypochlorite to the wood pulp in an amount from about 4 to about 12 kilograms of sodium chlorite per metric ton of wood pulp.

25. The process according to claim 16, characterized in that the wood pulp is bleached by adding hydrogen peroxide to the wood pulp in an amount of from about 35 to about 90 kilograms per metric ton of wood pulp.

26. A soft, shiny and resistant tissue paper product comprising cotton fluff fibers having an average fiber length of from about 0.3 to about 3.0 millimeters and an effective amount of a cationic starch derivative, characterized in that it is prepared from according to the process claimed in any of claims 16 to 25.