MXPA99007202A - Creping adhesive and process for creping tissue paper - Google Patents

Abstract

An adhesive for applying to a creping surface in the process for dry creping tissue paper is disclosed. The adhesive comprises cationic starch and optionally a polyvinyl alcohol and a water-soluble, thermosetting, cationic polyamide-epihalohydrin resin. The adhesive provides high adhesion and doctorability for dry creping.

Description

CREAMING ADHESIVE AND PROCESS TO CREATE PAPER TISU FIELD OF THE INVENTION This invention relates, in general, to creped tissue paper products and processes. More specifically, it refers to dry-creped tissue paper, where an embryonic paper web is formed in a Fourdrinier or similar papermaking apparatus, secured with adhesive while it is semi-dry to a cylindrical drying drum, after from which the drying of the web is substantially completed and creped from the drum by means of a flexible creping blade.

BACKGROUND OF THE INVENTION Sanitary paper products are widely used. These products are offered commercially in formats designed for a variety of uses, such as facial tissues, toilet paper and absorbent towels. The formats, that is, the base weight, thickness, strength, sheet size, distribution medium, etc. of these products often differ widely, but are linked by the common process by which they originate, the so-called creped papermaking process. Creping is a means to compact P8e7 mechanically the paper in the direction of the machine. The result is an increase in the basis weight (mass per unit area) as well as dramatic changes in many physical properties, particularly when measured in the machine direction. In general, creping is achieved with a flexible blade, a so-called doctor blade (also known as a doctor blade), against a Yankee dryer in an operation on the machine. This blade is also sometimes referred to as a creping blade or simply a creping apparatus. A Yankee dryer is a generally large 8-20 foot diameter drum that is designed to be pressurized with steam to provide a hot surface to complete the drying of the paper webs at the end of the papermaking process. The paper web that first forms in a foraminous forming carrier, such as a Fourdrinier mesh, where it is freed from the abundant water necessary to disperse the fibrous pulp, is generally transferred to a felt or cloth in a so-called press section where dewatering is continued either by mechanically compacting the paper or by some other dewatering method such as hot air drying, before it is finally transferred in the semi-dry condition to the surface of the Yankee so that drying is completed .

P867 The impact of the weft attached with the scraper blade is essential to impart to the paper web the properties sought by the manufacturers. Of particular importance are the softness, strength and volume. Softness is the tactile sensation perceived by the consumer as he holds a particular product, rubs it through his skin, or wrinkles it inside his hand. This tactile sensation is provided by a combination of several physical properties. One of the most important physical properties is related to the softness and it is generally considered by those skilled in the art that it is the stiffness of the paper web from which the product is made. Rigidity, in turn, is usually considered to depend directly on the strength of the weft. Resistance is the capacity of the product, and its constituent wefts, to maintain physical integrity and to resist tearing, breaking and defibering under conditions of use. Volume, as used herein, refers to the inverse of the density of a tissue paper web. It is another important part of the actual and perceived performance of tissue paper webs. The improvements in volume are added in general to the absorbent perception similar to a fabric. A portion of the volume of a frame P8S7 of tissue paper is imparted by the creping. The level of adhesion of the paper web to the dryer is also of vital importance since the control of the web is related to its travel in the space between the creping blade and the winder in which a roll of paper is being formed. Insufficiently adhering wefts tend to cause poor control of the sheet with the consequent difficulties in forming a uniform reel of paper. A loose sheet between the creping device and the reel will result in wrinkles, folds or interweaving the edges of the sheet on the rolled paper. The poorly formed rolls not only affect the reliability of the papermaking operation, but also the subsequent manufacturing operations of tissues and towels in which the rolls are converted into the tissue and towel products. The level of adhesion of the paper web to the dryer is also of vital importance since it is related to the drying of the weft. Higher levels of adhesion reduce the impedance of the heat transfer and cause the mesh to dry faster, allowing faster, more energy efficient operation. However, the level of adherence is not the only factor that determines the quality of the product and the P867 reliability of manufacturing. For example, it has been found that some adhesives form a bond between the weft and the scraper blade at the creping point so that the weft does not disengage properly, so that portions of the weft remain adhered to the dryer and travel. beyond the edge of the blade. This causes a defect in the frame and frequently causes the frame to break. In addition, while some of the adhesive buildup of the dryer is essential, excessive buildup or scratches may be formed with some types of adhesives. Stripes can cause differences in the adhesion profile across the width of the dryer. This can result in a mound or wrinkles in the finished roll of paper. Frequently, a second scraper blade is placed after the creping blade in order to remove any excess creping adhesive and other residue left behind. This blade is referred to as a cleaning blade. Cleaning blades and creping blades should be changed frequently to prevent coating with scratches and loss of blade control. The term "detachment or doctorate ability" as used herein refers to the relative ease with which the plot is disengaged from the dryer, without producing defects or without requiring frequent changes of the blades to prevent excessive accumulation. An important feature of a creping adhesive is that it is rewettable. "Rewettability", as used herein, refers to the ability of the adhesive film, which remains on the heated drying surface, to be activated by the moisture contained in the semi-dry paper web when the web is put on. contact with the heated drying surface. A marked increase in stickiness is indicative of high rewettability. Rewettability is important because only a portion of the drying surface is normally coated with adhesive in a given rotation of the Yankee dryer. The majority of the adhesion of the sheet to the dryer occurs by means of the creping adhesive deposited in the previous passes. There is a natural tendency of the paper web to adhere to the cylindrical dryer due to the accumulation of deposits of water-soluble components of the paper web. These water-soluble components form a film of adhesive which is rewetted at the transfer point of the weft to the cylindrical drum. The needs of the specific level and type of accession, however, have caused considerable activity between the researchers in the field. Accordingly, a wide variety of creping adhesives are known in the art. The use of glue of animal origin, for example, has been known for a long time. In addition, Bates, in the Patent of the States No. 3,926,716 incorporated herein by reference, describes a process for improving the adhesion of the wefts comprising the step of applying an aqueous polyvinyl alcohol. As Bates points out, the requirements for specific adhesion of the weft to the dryer drum are particularly demanding when the papermaking process is of the pattern densified category. Pattern densified frames are characterized by areas of relatively high density dispersed within a high volume field, including more recent advances where areas of relatively high density are continuous and the high volume field is discrete. A method for preparing patterned densified tissue paper is referred to as drying by air passage. The patterns densified in pattern offer particular stimulus to the adherence of the paper web to the rotating drying cylinder. This is because the weft is only secured to the dryer cylinder in the high density areas.

This stimulates adhesion not only due to the smaller surface area of contact with the dryer, but also because the weft must be distributed to the rotating cylinder at a relatively high level of fiber consistency due to the lower efficiency of the cylindrical dryer that originates from the smaller contact area. A web that has dried to a relatively high fiber consistency is more difficult to adhere to the dryer because a smaller amount of water is available to rewet the adhesive film at the point of transfer from the web to the dryer. In another example, Soerens, in U.S. Patent No. 4,501,640 incorporated herein by reference, discloses an adhesive comprising an aqueous mixture of polyvinyl alcohol and a water-soluble, cationic polyamide-epihalohydrin resin, water-soluble. . While a number of adhesives including these examples have been described and available, no single adhesive or mixture of adhesives has provided a satisfactory combination of dopability, rewettability, and adhesion level. Therefore, it is the object of this invention provide a tissue creping adhesive and a process for applying it that overcomes these limitations by offering an improved level of adhesion while maintaining doctoracy. These and other objects are obtained using the present invention as will be shown in the following description.

SUMMARY OF THE INVENTION The invention is an aqueous dispersion useful as a creping adhesive comprising a cationic starch. The cationic starch has between about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose starch. Preferably, the cationic substituents are selected from the group consisting of tertiary aminoalkyl ethers, quaternary ammonium alkyl ethers and mixtures thereof. The dispersion contains from about 90% to about 99.9% water and more preferably, from about 95% to about 99.9% water. Preferably, the starch comprises between about 10% and about 70% of the weight in dry of the dispersion, with the dispersion further comprising a polyvinyl alcohol. The polyvinyl alcohol is preferably a partially hydrolyzed polyvinyl acetate with a degree of hydrolysis greater than about 80%, more preferably from about 80% to about 95%. The molecular weight range for the polyvinyl alcohol useful for the present invention is from about 90,000 to about 140,000. An indirect indicator of molecular weight is viscosity, as used herein, with reference to that of a 4% aqueous dispersion of polyvinyl alcohol at 20 ° C. The polyvinyl alcohol of the present invention preferably has a viscosity greater than about 20 centipoise and more preferably more than about 35 centipoise. A further embodiment of the invention is an aqueous dispersion comprising the cationic starch and further comprising a cationic thermosetting resin of polyamide-epihalohydrin, soluble in water. The polyamide-epihalohydrin resin preferably comprises the reaction product of an epihalohydrin and a polyamide containing secondary or tertiary amine groups. The epihalohydrin is P867 preferably epichlorohydrin and the amine groups of the polyamide are preferably secondary amine groups derived from a polyalkylene polyamide and a dibasic, aliphatic, saturated carboxylic acid. The dibasic carboxylic acid preferably contains from about 3 to about 10 carbon atoms. The molar ratio of epihalohydrin to secondary amine groups in the polyamide is preferably from about 0.5 to 1 and from about 2 to 1. Another preferred embodiment of the present invention is an aqueous dispersion comprising from about 90% to about 99.9% of water and from about 10% to about 0.1% solids, with solids comprising from about 10% to about 70% of the cationic starch, from about 20% to about 85% of the polyvinyl alcohol, and from about 5% to about 40%. % of the polyamide-epihalohydrin resin, cationic, thermosetting, soluble in water. The invention further provides a process for creping tissue paper. The process comprises: a) applying to a rotating creping cylinder P867 an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1%, wherein the solid comprises a cationic starch having between about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose starch; b) pressing a web of tissue paper against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade. Another preferred embodiment of the present invention is a process for creping tissue paper, comprising: a) applying to an gyratory creping cylinder an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% or up to about 0.1% solids, wherein from about 50% to about 90% of the solids is a cationic starch having between about 0.001 and about 0.2 cationic substituents per anhydroglucose unit of starch, and from about 10% to about 50% of the solids is a polyamide-epihalohydrin resin, cationic, thermoing, water soluble; b) pressing a web of tissue paper against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade. Another preferred embodiment of the present invention is a process for creping tissue paper, comprising: a) applying to an oscillating creping cylinder an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1 % solids, wherein from about 10% to about 70% of the solids is a cationic starch having between about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose of starch, and from about 5% to about 40% of the solids is a water-soluble, cationic, cationic, polyamide-epihalohydrin resin, and from about 20% to about 85% of the solids is a polyvinyl alcohol; b) pressing a tissue paper web against the P867 creping cylinder to effect adhesion of the weft to the surface of the cylinder; and c) dislodging the creping cylinder web by contact with a scraper blade. The total amount of the creping adhesive applied is preferably from about 0.1 pound / ton to about 10 pound / ton based on the dry weight of the creping adhesive and the dry weight of the paper web. The unit pounds / ton, as used herein, refers to the dry amount of the creping adhesive measured in pounds relative to the dry amount of paper measured in tons. The tissue paper web may be comprised of several types of natural fibers including wood pulps of chemical and mechanical types. The preferred embodiment comprises papermaking fibers of both hardwood and coniferous wood types where at least about 50% of the paper fibers are hardwood and at least about 10% are coniferous wood. The tissue paper web can also comprise fillers in particulate forms. In its preferred embodiment, the method is used to prepare tissue paper with a basis weight between about 10 g / m and between about 50 g / m and greater P8S7 preference between about 10 g / m and about 30 g / m. The preferred density is between about 0.03 g / cm and about 0.6 g / cm, and more preferably between about 0.05 g / cm and 0.2 g / cm. All percentages, ratios and proportions herein are by weight unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a schematic representation of the papermaking process incorporating the preferred embodiment of the present invention comprising a new adhesive for the dry creping of tissue paper.

DETAILED DESCRIPTION OF THE INVENTION Having described an environment for the invention, it will be described below particularly in this detailed description and in the appended examples. This description is provided as an aid for the understanding of the invention; but it is not proposed to limit the invention, which is defined by the claims that point in a particular way and claim distinctly the matter considered as the P867 invention As used herein, the term "comprising" means that the various components, ingredients, or steps may be used together in the practice of the present invention. Accordingly, the term "comprising" embraces the more restrictive terms "consisting essentially of" and "consisting of". As used herein, the term "water soluble" refers to materials that are soluble in water to at least 3% by weight at 25 ° C. As used herein, the terms "tissue paper web", plot of paper, weft, sheet of paper and paper product "all refer to sheets of paper made by a process comprising the steps of forming an aqueous pulp, deposit this raisin on a foraminada surface, such as a mesh Fourdrinier, and remove the water from the paste by gravity or by vacuum-assisted drainage, with or without pressing, and by evaporation, which comprises the final steps of adhering the sheet in a semi-dry condition to the surface of a Yankee dryer, which ends the removal of the water by evaporation to an essentially dry state, the removal of the Yankee dryer frame by means of a flexible creping blade, and the winding of the P867 the resulting sheet on a reel. The terms "multilayer tissue paper web, multilayer paper web, multilayer web, multilayer paper web, and multilayer paper product" are all used interchangeably in the art to refer to sheets of paper prepared from two or more layers of an aqueous pulp which are preferably comprised of different types of fibers, fibers which are typically relatively long coniferous wood fibers and relatively short hardwood fibers, as used in the production of tissue paper. The layers that are preferably formed from the deposition of separate streams of diluted pulps of fibers in one or more endless, foraminated surfaces. If the individual layers are formed on separate, foraminated surfaces, the layers can subsequently be combined when wet to form a multilayer tissue paper web. As used herein, the term "single-sheet tissue product" means that it is comprised of a creped tissue sheet; the sheet may be substantially homogeneous in nature or may be a multilayer tissue paper web. As used herein, the term "multi-leaf tissue product" P867 means that it is comprised of more than one sheet of creped tissue. The sheets of a multi-sheet tissue product may be of a substantially homogeneous nature or may be plies of multilayer tissue paper. In its most general form, the invention is an aqueous dispersion useful as a creping adhesive comprising a cationic starch. The dispersion contains from about 90% to about 99.9% water and more preferably, from about 95% to about 99.9% and the cationic starch has a degree of substitution ranging from about 0.001 to about 0.2 cationic substituents per units of anhydroglucose of starch. As used herein, the term "aqueous dispersion" refers to compositions consisting predominantly of water and containing at least one additional component homogeneously distributed throughout the composition. The essential element is the homogeneity of the composition. It is not necessary for all components to dissolve at the molecular level. In this way, the term "aqueous dispersions" encompasses the more restrictive term "aqueous solution". As used herein, the term "starch" "cationic" is defined as starch, as naturally derived, which has been further chemically modified to impart a cationic constituent portion.Preferably, starch is derived from corn or potatoes, although it can be derived from other sources such as example rice, wheat or tapioca Waxy corn starch also known industrially as amioca starch is particularly preferred.Amioca starch differs from common tooth corn starch in that it is completely amylopeptin, while common corn starch contains both amylopeptin as amylose Further, several unique characteristics of amioca starch are described in "Amioca - The Starch from Waxy Corn", HH Schopmeyer, Food Industries, December 1945, pp. 106-108.Cateric starches can be divided into the following general classifications: (1) tertiary aminoalkyl ethers, (2) onium starch ethers including quaternary amines nostrils, phosphonium and sulfonium derivatives, (3) primary and secondary aminoalkyl starches, and (4) miscellaneous (eg, imino starches). New cationic products continue to develop, but the tertiary aminoalkyl ethers and the alkyl quaternary ammonium ethers are the main commercial types, and are preferred P8S7 for use in the present. Suitable starches are produced by the National Starch and Chemical Company, (Bridgewater, New Jersey) under the trade name RediBOND. The grades with cationic portions only as for example RediBOND 5320R and RediBOND 5327 are suitable, and grades with additional anionic functional groups such as RediBOND 2005R, are also suitable. In one embodiment of the invention, the starch preferably comprises between about 10% and about 70% of the dry weight of the dispersion with about 30% to about 90% of the dry weight of the dispersion comprising a polyvinyl alcohol. Any suitable polyvinyl alcohol can be used in the present invention to form an adhesive film. The prior art, such as, for example, Bates, in U.S. Patent No. 3,926,716 describes the types of polyvinyl alcohol particularly suitable for the application. Commercial supplies of polyvinyl alcohol in solid form can be obtained under various brand names including Airvol, a trademark of Air Products Company of Allentown, PA and Elvanol®, a trademark of E. I. duPont de Nemours of Wilmington, DE. These P867 Resins can be easily made in water to form aqueous solutions that are easily sprayed for application to a Yankee dryer or to a semi-dry tissue web. The polyvinyl alcohol is preferably a partially hydrolyzed polyvinyl acetate with a degree of hydrolysis greater than about 80% and more preferably from about 80% to about 95%. The molecular weight range for the polyvinyl alcohol useful for the present invention is from about 90,000 to about 140,000. An indirect indicator of molecular weight is viscosity, as used herein, referring to that of an aqueous dispersion at 4% polyvinyl alcohol at 20 ° C. The polyvinyl alcohol of the present invention preferably has a viscosity greater than about 20 centipoise and more preferably more than about 35 centipoise. In another embodiment of the invention, the dry weight of the aqueous dispersion comprises from about 50% to about 90% of the cationic starch while also comprising from about 10% to about 50% of a cationic, polyamide-epihalohydrin resin of P867 thermosetting, soluble in water. The water-soluble, cationic, cationic polyamide-epihalohydrin resin comprises the reaction product of an epihalohydrin and a polyamide containing secondary amine groups or tertiary amine groups. Commercial supplies of particularly preferred polyamide-epihalohydrin resins can be obtained under various trademarks including Kymene and Crepetrol, trademarks of Hercules Inc. of Wilmington, DE, and Unisoft and Rezosol, trademarks of Houghton International, Inc. of Valley Forge, PA. These resins are supplied as a concentrated solution in water and need only be diluted in order to be sprayed easily for application to a Yankee dryer or to a semi-dry tissue web. The basic preparation chemistry of the water-soluble cationic, cationic, polyamide-epihalohydrin resin is fully described in U.S. Patent No. 2,926,116 issued to Kiem, February 23, 1960, Patent of the United States of America. No. 3,058,873 issued to Kiem, et al. on October 16, 1962, and United States Patent No. 3,772,076 granted to Kiem on the 13th P867 November 1973, all of which are incorporated herein by reference. Preferably, the polyamide-epichlorohydrin resin comprises a water-soluble polymeric reaction product of epichlorohydrin, and a water-soluble polyamide having secondary amine groups. In the preparation of a particularly preferred resin, a dibasic carboxylic acid is first reacted with the polyalkylene polyamine, preferably in an aqueous solution, under suitable conditions to produce a water-soluble polyamide with repeating units.

-NH (CnH2nHN) x-CORCO- where n and x are each 2 or more and R is the divalent hydrocarbon radical of the dibasic carboxylic acid containing from about 3-10 carbon atoms. The preparation of the resin is then terminated by reacting the water-soluble polyamide with an epihalohydrin, particularly epichlorohydrin, to form the water-soluble, cationic polyamide-epihalohydrin thermosetting resin.

P867 The secondary amine groups of the polyamide are preferably derived from a polyalkylene polyamine, for example, polyethylene polyamides, polypropylene polyamines or polybutylene polyamines, and the like, with diethylenetriamine which is preferred. Dicarboxylic acid is one of the carboxylic, dibasic, aliphatic, saturated acids containing from about 3 to about 10 carbon atoms, such as, for example, succinic, adipic, azelaic, and the like, and mixtures thereof. Dicarboxylic acids containing from 4 to 8 carbon atoms are preferred, with the adipic acid which is the most preferred. Preferably, the molar ratio of polyalkylene to dibasic carboxylic acid is from about 0.8 to 1 to about 1.5 to 1. The molar ratio of epihalohydrin to secondary amine groups in the polyamide is preferably from about 0.5 to 1 to about 2 to 2. In another aqueous dispersion, preferred according to the present invention, the dispersion comprises from about 90% to about 99.9% water and from about 10% to about 0.1% solids, with the solids comprising about 10% to about 70% of the cationic starch, from about 20% to about 85% of the polyvinyl alcohol, and from about 5% to about 40% of the water-soluble cationic, thermosetting polyamide-epihalohydrin resin. The invention further provides a process for creping tissue paper. The process comprises: a) applying to an gyratory creping cylinder an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1% solids, wherein the solids comprise a cationic starch having between about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose of starch; b) pressing a web of tissue paper against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade. Another preferred embodiment of the present invention is a process for creping tissue paper, comprising: a) applying to a rotating creping cylinder P8G7 an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1% solids, wherein from about 50% to about 90% of the solids is a cationic starch having between about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose of starch, and from about 10% to about 50% of the solids is a polya ida-epihalohydrin, cationic, thermosetting, water-soluble resin; b) pressing a web of tissue paper against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade. Another preferred embodiment of the present invention is a process for creping tissue paper, comprising: a) applying to an oscillating creping cylinder an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1 % solids, where from about 10% to about 70% of the solids is a starch cationic having between about 0.001 and about 0.2 cationic substituents per unit of starch anhydroglucose, from about 5% to about 40% of the solids is a water-soluble, cationic, cationic polyamide-epihalohydrin resin, and from about 20 % up to about 85% of the solids is a polyvinyl alcohol; b) pressing a web of tissue paper against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade. The total amount of the creping adhesive applied is preferably from about 0.1 pounds / ton to about 10 pounds / tons based on the dry weight of the creping adhesive and the dry weight of the paper web. The unit pounds / ton, as used herein, refers to the dry amount of the creping adhesive measured in pounds relative to the dry amount of paper measured in tons.

P867 PREPARATION OF THE TISSUE PAPER FRAMEWORK Components of the Aqueous Paper Pulp It is anticipated that the wood pulp in all its varieties will normally comprise the paper fibers used in this invention. However, other fibrous cellulose pulps can be used, such as, for example, cotton linters, bagasse, rayon, etc., and none are known. The wood pulps useful herein include chemical pulps such as sulphite pulps and sulfate pulp (sometimes called Kraft) as well as mechanical pulps that include, for example, ground wood, thermomechanical pulp (TMP) and chemo-thermomechanical pulp (CTMP). Pulps derived from both deciduous and coniferous trees can be used. Both the hardwood pulps and the coniferous wood pulps, as well as combinations of the two, can be used as paper fibers for the tissue paper of the present invention. The term "hardwood pulps" as used herein refers to fibrous pulp derived from the woody substance of deciduous trees (angiosperms), while "coniferous wood pulps" are fibrous pulps derived from the woody substance of trees coniferous (gymnosperms). Mixtures of hardwood kraft pulp, pà © s7 especially eucalyptus, and Kraft pulps of northern coniferous wood (NSK) are particularly suitable for the manufacture of the tissue frames of the present invention. Another preferred embodiment of the present invention comprises stratified tissue webs, where, and more preferably, hardwood pulps such as eucalyptus are used for the outer layer (s) and where Kraft pulps are used. of coniferous wood from the north are used for the inner layer (s). Also applicable to the present invention are fibers derived from recycled paper, which may contain any or all of the above categories of fibers. The particulate fillers, which include clays, calcium carbonate, titanium dioxide, talcum, aluminum silicate, calcium silicate, alumina trihydrate, activated carbon, pearl starch, calcium sulfate, glass microspheres, diatomaceous earth, and mixtures of they can also be included in the pulp, aqueous. Other materials, of which the following are examples, may be added to the aqueous pulp or embryonic web, to impart other characteristics to the product or to improve the papermaking process, as long as they do not interfere or P867 contravene the advantages of the present invention. It is sometimes useful, for purposes of retention and strength of the weft, to include starch as one of the ingredients of the pulp, aqueous, especially cationic starch. Starches particularly suitable for this purpose are produced by the National Starch and Chemical Company, (Bridgewater, New Jersey) under the trademark RediBOND. It is common to add a kind of cationic charge alteration to the papermaking process to control the zeta potential of the pulp, aqueous as it is distributed to the papermaking process. One suitable material is Cypro 514R, a product of Cytec, Inc. of Stamford, C. It is also common to add retention aids. Multivalent ions can be added effectively to the aqueous pulp in order to improve the retention of fine particles which could otherwise remain suspended in the recirculating water system of the paper machine. The practice of adding alum, for example, has been known for a long time. More recently, polymers carrying many loading sites along the length of the chain have been used effectively for this purpose. They are expressly included P867 both anionic and cationic flocculants within the scope of the present invention. Flocculants such as RETEN 235R, a product of Hercules, Inc. of Wilmington, Delaware and Accurac 171R, a product of Cytec, Inc. of Stamford, CT, are examples of anionic flocculants. Flocculants such as RETEN 157R, a product of Hercules, Inc. of Wilmington, Delaware, and Accurac 91, a product of Cytec, Inc. of Stamford, CT, are examples of acceptable cationic flocculants. The use of high anionic charge, high surface area microparticles for the purposes of improving formation, drainage, strength and retention are well taught in the art. See, for example, U.S. Patent No. 5,221,435 issued to Smith on June 22, 1993, incorporated herein by reference. Common materials for this purpose are colloidal silica, or bentonite clay. The incorporation of these materials is expressly included within the scope of the present invention. The advantages of the present invention are realized more particularly for grades of paper without permanent wet strength. Wet strength resins, particularly the polyamide-epichlorohydrin type, which are more detailed particularly in other parts of this specification, it frequently provides some degree of crepe control even when added to the pulp, watery However, these advantages are often accompanied by the presence of a permanent wet strength in the product, a property that is often a compromise and the addition of polyamide-epichlorohydrin in the final mesh of the papermaking process is not as effective in the promotion of crepe benefits as can be achieved by using the polymer directly in the creping operation. Creped paper products, which must have limited strength when wet due to the need to dispose of them through sanitary sewer or sewer systems, require wet flash resins. Resins of wet fugitive resistance impart a wet strength that is characterized by a decay of part or all of its power when in the presence of water. If the wet fugitive resistance is desired, the binder materials may be chosen from the group consisting of dialdehyde starch or other resins with aldehyde functional groups such as for example Co-Bond 1000R offered by National Starch and Chemical Company, P867 Parez 750R, offered by Cytec of Stamford, CT and the resin described in U.S. Patent No. 4,981,557 issued January 1, 1991 to Bjorkquist and incorporated herein by reference. If improved absorbency is needed, surfactants can be used to treat the creped tissue paper webs of the present invention. The surfactants preferably have alkyl chains with eight or more carbon atoms. Exemplary anionic surfactants are linear alkyl sulfonates, and alkyl and benzene sulfonates. Non-ionic surfactants, eg, are alkyl glycosides including esters of alkyl glycosides such as for example esta SL-40R is available from a, Inc. (New York, NY); alkyl glycoside ethers as described in U.S. Patent No. 4,011,389, issued to W. K. Langdon, et al. March 8, 1977; and alkyl polyethoxylated esters such as for example Pegosperse 200 ML available from Glyco Chemicals, Inc. (Greenwich, CT) and IGEPAL RC-520R available from Rhone Poulenc Corporation (Cranbury, NJ). Chemical softening agents are optionally included as optional ingredients. Acceptable chemical softening agents comprise the well-known dialkyldimethylammonium salts as P867 for example dimethyldimethylammonium chloride, dimethylammonium dimethylammonium methylisulfate, and dimethylammonium di (hydrogenated) tallow chloride, with dimethyl ammonium di-methyl sulfate di (hydrogenated) which is preferred. This particular material is commercially available from Witco Chemical Company Inc. of Dublin, Ohio under the trade name Varisoft 137. The biodegradable mono and di-ester variations of the quaternary ammonium compound can also be used and are within the scope of the present invention. The above listings of optional chemical additives are proposed to be merely exemplary in nature and not to limit the scope of the invention.

Preparation of the Aqueous, Paper Pulp Those skilled in the art will recognize that not only the qualitative chemical composition of the pulp is important for the creped papermaking process, but also the relative amounts of each component and the presence and timing of the paper. the addition, among other factors. The following techniques are available in the preparation of pulp, aqueous, although its delineation should not be considered as limiting the scope of this P867 invention, which is defined by the claims set forth at the end of this specification. The paper fibers are first prepared by releasing the individual fibers in an aqueous pulp by any of the common pulp processing methods suitably described in the prior art. The refining is then carried out, if necessary, on the selected parts of the pulp. In a preferred arrangement, a pulp of relatively short pulp fibers, comprising hardwood pulp, is prepared while a relatively long pulp of paper pulp is separately prepared. The fate of the pulp resulting from short fibers will be directed to the outer chambers of a three layer main box to form surface layers of a three layer tissue in which an inner layer of long fibers is formed outside of a chamber inside the main box in which the pulp of relatively long paper fibers is directed. The resulting, filled tissue paper web is particularly suitable for converting it into a single sheet tissue product. In a preferred alternative arrangement, the pulps of long and short fibers mentioned are formed P867 above and the fate of the resultant short fiber pulp will be directed to a chamber of a two-chamber main box to form a layer of a two-layer tissue in which an alternative layer of long fibers of the second chamber is formed in the main box in which the pulp of relatively long paper fibers is directed. The resulting tissue plot, padding is particularly suitable for converting it into a multi-sheet paper product comprising two sheets in which each sheet is oriented so that the layer comprised of relatively short paper fibers is on the surface of the two-sheet tissue product. Those skilled in the art will also recognize that the apparent number of cameras in a master box can be reduced by directing the same type of pulp, aqueous to adjacent chambers. For example, the three-chamber main box mentioned above can be used as a two-chamber main box in a simple manner by essentially directing the same, aqueous pulp to either of the two adjacent chambers.

The Papermaking Process Figure 1 is a schematic representation -P867 of the papermaking process incorporating the preferred embodiments of the present invention comprising the new process for dry creping the tissue paper. These preferred embodiments are described in the following analysis, where reference is made to Figure 1. Figure 1 is an elevation, side view of a papermaking machine 80, preferred for making paper in accordance with the present invention. With reference to Figure 1, the papermaking machine 80 comprises a layered or layered main box 81 having an upper chamber 82, a central chamber 82b, and a bottom chamber 83, a division ceiling 84, and a 85 Fourdrinier mesh making a circuit on and around the anterior roller 86, a diverter 90, vacuum suction boxes 91, the bed roller 92, and a plurality of spin rollers 94. In the operation, a pulp is pumped through the upper chamber 82, a second pulp is pumped through the central chamber 82b, while a third pulp is pumped through the bottom chamber 83 and from there out of the dividing roof 84 in a relation above and below the 85 Fourdrinier mesh, to form therein an embryonic web 88 comprising the layers P867 88a, and 88b and 88c. Dewatering occurs through the Fourdrinier mesh 85 and is assisted by the derailleur 90 and the vacuum boxes 91. As the Fourdrinier mesh does its run back in the direction shown by the arrow, the showers 95 clean it before it starts. another one passed over the previous roller 86. In the frame transfer zone 93, the embryonic web 88 is transferred to a carrier web 96 foraminated by the action of the vacuum transfer case 97. The carrier fabric 96 transports the web from the transfer zone 93 beyond the vacuum dewatering box 98, through the pre-dryers 100 by passage blowing and beyond the two spinning rollers 101, forming the web 106 of tissue paper, embryonic, semi-dry, still supported by the foraminada carrier fabric 96. After the weft is transferred to a Yankee dryer 108 in a subsequent step, the carrier fabric 96 is then cleaned and drained as its circuit is completed as it passes over and around the additional spin rollers 101, the sprinklers 103, and the vacuum dewatering box 105.

APPLICATION OF THE AQUEOUS DISPERSION OF CREPATE ADHESIVE The present invention employs the application of a creping adhesive comprising a dispersion aqueous starch and optionally a polyvinyl alcohol and a cationic, thermosetting polyamide-epihalohydrin resin, soluble in water. Preferably, the solids concentration of the aqueous dispersion is between about 0.1% and about 10% at the point of application. More preferably, the concentration of solids is between about 0.1% and about 5% at the point of application. While several creping adhesive application means are anticipated and none is known, the preferred method of application is by aqueous dispersion by means of a spray arm directed on the surface of the Yankee dryer prior to the transfer of the paper web. semi-dry tissue. With reference to Figure 1, the point of application of the dispersion by means of this preferred embodiment is represented by the spray arm 107. The use of multiple spray arms each carrying ingredients comprising the present invention is specifically within the scope of the present invention. For example, with reference to Figure 1, the spray arm 108 is optional. If allowed, the dispersions according to the present invention are P8S7 they can direct by means of spray arm 107 or 108, or both.

Pressing the Weft Against the Creping Cylinder In the present invention, the tissue paper web while in a semi-dry condition is pressed against a creping cylinder, most commonly a heated drying surface, called a Yankee dryer, aided by creping adhesives applied in the previous steps. The weft is secured when pressed to the surface of the cylinder. More preferably, pressure is provided from a proposed cylindrical drum to achieve uniform adhesion of the semi-dry web to the dryer. Vacuum can also be applied to the weft as it is pressed against the Yankee surface. Multiple Yankee dryer drums can also be employed in the present invention. With reference to Figure 1, the semi-dry tissue paper web is secured to the cylindrical surface of the Yankee dryer 109 aided by the adhesive applied by the spray arm 107 and 108. Each arm 107 or 108, or both, may apply a dispersion according to the present invention. The adhesion of the weft is stimulated by the use of the steel drum, cylindrical, P867 Opposite, 102. Drying is terminated in Yankee dryer 109 heated with steam and hot air which is heated and circulated through drying hood 110 by means not shown. The web is then creped dry from the Yankee dryer 109 by the scraper blade 111, called the creping blade, after which the paper sheet 70 comprising a Yankee side layer 71, a core layer 73 and a layer is designated. 75 aside from Yankee. The sheet of paper 70 then passes between the calender rolls 112 and 113, around a circumferential portion of the reel 115, and from there it is wound on a roll 116 in a core 117 placed on the arrow 118. Removal of the excess coating of the surface of the dryer is effected by means of a second scraping blade, 114, called a cleaning blade. Also, with respect to the process conditions for making the example paper sheet 70, the paper web is preferably dried at about 80% fiber consistency, and more preferably at about 96% fiber consistency before creping. The present invention is applicable to creped tissue paper in general, including, but not limited to, creped tissue paper, conventionally pressed with P867 felt, creped tissue paper, densified, with a high volume pattern; and creped, non-compacted, high-volume tissue paper. The creped tissue paper webs of the present invention have a basis weight of between 10 g / m2 and approximately 100 g / m. In its preferred embodiment, the filled tissue paper of the present invention has a basis weight between about 10 g / m and about 50 g / m and more preferably between about 10 g / m and about 30 g / m. The creped tissue meshes suitable for the present invention have a density of about 0.60 g / cm or less. In its preferred embodiment, the loaded tissue paper of the present invention has a density between about 0.03 g / cm and about 0.6 g / cm3 and more preferably, between about 0.05 g / cm and 0.2 g / cm. The present invention is further applicable to multi-ply tissue paper webs. Tissue structures formed from multilayer paper webs are described in U.S. Patent No. 3,994,771 to Morgan, Jr. et al., issued November 30, 1976, United States Patent No. 4,300,981, issued by Carstens, issued November 17, 1981, United States Patent No. 4,166,001, Dunning et al, issued August 28, 1979 and European Patent Publication No. 0 613 979 Al de Edwards et al., Published September 7, 1994, all of which are incorporated herein. by reference. The layers are preferably comprised of different types of fibers, fibers that are typically relatively long coniferous wood fibers and relatively short hardwood fibers as used in the manufacture of multilayer tissue paper. The multilayer tissue paper webs suitable for the present invention comprise at least two superimposed layers, an inner layer and at least one outer layer contiguous with the inner layer. Preferably, the multilayer tissue papers comprise three superposed layers, an inner or central layer, and two outer layers, with the inner layer located between the two outer layers. The two outer layers preferably comprise a primary constituent formed of relatively short fiber filaments of paper having an average fiber length between about 0.5 and about 1.5 mm, preferably less than about 1.0 mm. These short papermaking fibers typically comprise hardwood fibers, preferably hardwood kraft fibers, and higher preference derived from eucalyptus. The inner layer preferably comprises a primary constituent formed of relatively long fiber filaments of paper having an average fiber length of less than about 2.0 mm. These long paper fibers are typically coniferous wood fibers, preferably, Kraft fibers from coniferous wood from the north. Preferably, the majority of the particulate filler of the present invention is contained in at least one of the outer layers of the multi-ply tissue paper web of the present invention. And most preferably, most of the particulate filler of the present invention is contained in both outer layers. The creped tissue products made from the creped tissue paper webs, single layer sheets where several layers can be individual sheet tissue products or multi-sheet tissue products. The equipment and methods are well known to those skilled in the art. In a typical process, a low consistency pulp is provided in a pressurized main box. The main box has an opening for the distribution of a thin deposit of paste on the Fourdrinier mesh, to form P867 a wet plot. The web is then typically drained to a fibrous consistency of between about 7% and about 25% (based on the total weight of the web) by vacuum dewatering. More preferable variations of the papermaking process of the present invention include so-called pattern densified methods in which the resulting structure is characterized as having a relatively high volume field of relatively low fibrous density and an array of densified areas of fibrous density relatively high dispersed within the high volume field. The high volume field is alternatively characterized as a field of pillow regions. The densified zones are alternatively referred to as knuckle regions. The densified zones can be discreetly spaced within the high volume field or can be interconnected, either completely or partially, within the high volume field. Preferably, the relatively high density areas are continuous and the high volume field is discrete. Preferred processes for making patterned densified tissue webs are described in U.S. Patent No. 3,301,746, issued to Sanford and Sisson on January 31, 1967, U.S. Patent No.

P867 3,974,025, granted to Peter G. Ayers on August 10, 1976, and United States Patent No. 4,191,609, granted to Paul D. Trokhan on March 4, 1980 and United States Patent No. 4,637,859 granted to Paul D. Trokhan on January 20, 1987, U.S. Patent No. 4,942,077 issued to Wendt et al. on July 17, 1990, European Patent Publication No. 0 617 164 Al, Hyland et al., published September 28, 1994, European Patent Publication No. 0 616 074 Al of Hermans et al., published on September 21, 1994, all of which are incorporated herein by reference. To form pattern densified wefts, the weft transfer step immediately after forming the weft is a forming fabric instead of a felt. The plot is juxtaposed against an array of supports that comprise the forming fabric. The screen is pressed against the array of supports, thereby resulting in densified zones in the screen at the locations corresponding geographically to the points of contact between the arrangement of the supports and the wet screen. The rest of the non-compressed frame during this operation is referred to as the high volume field. This high volume field can be further reduced in density by the application of pressure P867 of fluid, as for example with a vacuum type device or a blow-through dryer. The web is drained, and optionally pre-dried, in such a way as to substantially prevent compression of the high volume field. This is preferably achieved by fluid pressure, as for example with a vacuum-type device or through-blow dryer, or alternatively by mechanical pressing of the weft against an array of supports where the high-volume field is not compressed. The operations of dewatering, optional pre-drying and the formation of the densified zones can be integrated or partially integrated to reduce the total number of processing steps carried out. The moisture content of the semi-dry web at the point of transfer to the Yankee surface is less than about 40% and the hot air is forced through the semi-dry web while the semi-dry web is on the web to form a web structure. low density. The patterned densified pattern is transferred to the Yankee dryer and dried to completion, preferably still avoiding mechanical pressing. In the present invention, preferably about 8% to about 55% of the creped tissue surface comprises densified knuckles having a P867 Relative density of at least 125% of the high volume field density. The arrangement of supports is preferably a printing carrier fabric having a knuckle pattern shift that operates as the arrangement of supports that facilitates the formation of densified zones in the application of pressure. The knuckle pattern constitutes the array of supports previously referred to. Printing carrier fabrics are described in United States Patent No. 3, 301,746 to Sanford and Sisson, issued January 31, 1967, United States Patent No. 3,821,068 to Salvucci, Jr. et al., Issued May 21, 1974, United States Patent No. 3,974,025 to Ayers. , issued August 10, 1976, U.S. Patent No. 3,573,164 to Friedberg et al., issued March 30, 1971, U.S. Patent No. 3,473,576 to Amneus, issued October 21, 1969, U.S. Patent No. 4,239,065, to Trokhan, issued December 16, 1980; and U.S. Patent No. 4,528,239 to Trokhan, issued July 9, 1985, all of which are incorporated herein by reference . Most preferably, the embryonic web is made to fit the surface of a fabric of drying / printing of open mesh by the application of a fluid force to the web and then thermally pre-drying on the web as part of a low density papermaking process. Another variation of the processing steps included within the present invention include the formation of so-called multi-layered, non-densified patterned tissue structures, uncompacted as for exa described in United States Patent No. 3,812,000 issued to Joseph L. Salvucci, Jr. and Peter N. Yiannos on May 21, 1974, and U.S. Patent No. 4,208,459, issued to Henry E. Becker, Albert L. McConnell, and Richard Schutte of June 17, 1980 , both are incorporated herein by reference. In general, multi-layered, non-densified, unpacked tissue paper structures are prepared by depositing a pulp in a foraminated forming mesh such as a Fourdrinier mesh to form a wet web, draining the web and removing the additional water. without mechanical compression until the weave has a fibrous consistency of at least 80%, and creping the mesh. The water is removed from the weft by vacuum dewatering and thermal drying. The resulting structure is a soft but weak high-volume sheet of relatively non-fiber fibers P867 compacted The bonding material is preferably applied to portions of the weft before creping. The advantages related to the practice of the present invention include the ability to improve the speed of the papermaking operation by virtue of improving the adhesion or control of the sheet between the creping blade and the spool. While not wishing to be bound by theory, the following is an attempt to explain why the invention provides advantageous adhesion. Cationic starch due to its carbohydrate structure similar to a cellulose and its characteristic surface charge is a specific adhesive for cellulose pulp and is capable of producing cotely high adhesive strengths. It is also rehumectable. Further modification with either polyvinyl alcohol or a water-soluble cationic polyamide-epihalohydrin resin can improve dopability while retaining the high-adhesive characteristics of cationic starch. The term "strength" as used herein refers to the total resistance to stress, the determination method for this measurement is included in a final section of this specification. The tissue paper webs according to the present invention are P867 powerful. This generally means that their total resistance to tension is at least about 100 g / inch, more preferably more than about 300 g / inch. The tissue paper web of the invention can be used in any application where absorbent, soft tissue paper webs are used. Particularly advantageous uses of the tissue paper web of the invention are in tissue paper and facial tissue products. The single-sheet and multi-sheet tissue paper products can be produced from the plots of the present invention.

ANALYTICAL AND TEST PROCEDURES Density The density of multilayer tissue paper, as this term is used herein, is the average density calculated as the basis weight of that paper divided by the calibrating gel, with the appropriate unit conversions incorporated in the I presented. The multilayer tissue paper calibrator, as used herein, is the thickness of the paper when it is subjected to a compressive load of 95 g / inch (15.5 g / cm).

B. Determination of Molecular Weight The distinctive, essential characteristic of polymeric materials is their molecular weight. Properties that have polymers capable of being used in a variety of applications derive almost cotely from their macromolecular nature. In order to fully characterize these materials it is essential to have some means to define and determine their molecular weights and molecular weight distributions. It is more correct to use the term in relation to the molecular mass instead of the molecular weight, but the latter is used more generally in polymer technology. It is not always practical to determine the molecular weight distributions. However, this is becoming a more common practice using chromatographic techniques. Instead, the resource is made to express the molecular size in terms of the average molecular weights.

AVERAGE MOLECULAR WEIGHTS If we consider a simple distribution of molecular weight that represents the weight fraction (W¿) of molecules that have the relative molecular mass (M¿), it is possible to define several useful average values. The averaging carried out based on the number of P867 molecules (N- of a particular size (M-J provides the numerical average molecular weight An important consequence of this definition is that the Average Molecular Weight Numeric in grams contains the number of Avogadro molecules. This definition of molecular weight is consistent with that of monodisperse molecular species, ie, molecules that have the same molecular weight. Of greater significance is the recognition that if the number of molecules in a given mass of a polydisperse polymer can be determined in some way, then Mn, can be easily calculated. This is the basis of colligative property measurements. Averaging the base of the fractions by weight (W.J of the molecules of a given mass (M-leads to the definition of the weighted molecular weights IV * £ NÍM » Mw is a more useful means to express the molecular weights of polymer than Mn since it reflects from P867 more accurate properties, such as, for example, the melt viscosity and mechanical properties of the polymers and is therefore used in the present invention.

C. MEASURING THE SOFTNESS OF THE PAPER TISSUE PANEL Ideally, before the softness test, the paper samples to be tested should be conditioned according to the Tappi method # T4020M-88. Here, the samples are preconditioned for 24 hours at a relative humidity level of 10 to 35% and within a temperature range of 22 to 40 ° C. After this preconditioning step, the samples should be conditioned for 24 hours at a relative humidity of 48 to 52% and within a temperature range of 22 to 24 ° C. Ideally, the softness panel test should be carried out within the limits of a constant temperature and a quarter of humidity. If this is not feasible, all samples, including controls, must experience identical environmental exposure conditions. The softness test is performed as a comparison performed in a similar way to that described in "Manual on Sensory Testing Methods", ASTM Special Technical Publication 434, published by American Society for Testing and Materials 1968 and is incorporated herein by reference. Softness is evaluated by the subjective test that is referred to as a paired difference test. The method employs a standard external to the test material itself. For the perceived softness to the touch two samples are presented in such a way that the subject can not see the samples, and the subject is asked to choose one of them based on the softness to the touch. The result of the test is reported in what is referred to as the panel scoring unit (PSU). With respect to the softness test to obtain the softness data reported herein at PSU, a number of softness panel tests are performed. In each test, ten judges are asked to rate the relative softness of three sets of paired samples. The pairs of samples are judged one pair at a time for each trial one sample of each pair designated with X and the other with Y. Briefly, each sample X is graded against its sample Y paired as follows: 1. a degree of plus one is given if X is judged to be a little softer than Y, and a degree of minus one is given if Y is judged to be a little softer than X; P867 2. a degree of plus two is given if X is judged to be a little softer than y, and a degree of minus two is given if Y is judged to be a little softer than X; 3. a degree of plus three is given if X is judged to be a little softer than Y, and a degree of minus three is given if Y is judged to be a little softer than X; and finally; 4. a degree of plus four is given if X is judged to be completely softer than Y, and a minus four degree is given if Y is judged to be completely softer than X. The grades are averaged and the resulting value is in PSU units. The resulting data is considered the results of a panel test. If more than one pair of samples are evaluated then all sample pairs are sorted according to their grades by statistical or paired analysis.

Then, the classification alternates up or down in value as required to give a value PSU zero for which the sample is ever chosen to be the zero-based norm. The other samples then have values of plus or minus as determined by their relative degrees with respect to the zero-based norm. The number of panel tests performed and P8S7 averaged is approximately 0.2 PSU represents a significant difference in subjective perceived softness.

D. TISU PAPER RESISTANCE MEASUREMENT Dry Stress Resistance Stress resistance is determined in one-inch-wide strips using a Thwing-Albert Standard Intelect II Standard Tensile Tester (Thwing-Albert Instrument Co ., 10960 Dutton Rd., Philadelphia, PA, 19154). This method is proposed for use on finished paper products, reel samples, and unconverted stock.

Sample Conditioning Preparation Before the stress test, the paper samples to be tested should be conditioned according to the Tappi method # T402OM-88. All paper and plastic packaging materials should be carefully removed from the paper samples before testing. The paper samples should be conditioned for at least two hours at a relative humidity of 48 to 52% and within a temperature range of 22 to 24 ° C. The preparation of the sample in all aspects of the stress test is also P867 It must be carried out with the confines of constant temperature and a quarter of humidity. For the finished product, any damaged product is downloaded. Then, 5 strips of four useful units (also called leaves) are removed and stacked one on top of the other to form a long stack with the perforations between the matching sheets. Identify sheets 1 and 3 for voltage measurements in the machine direction and sheets 2 and 4 for voltage measurements in the transverse direction. Then, it is cut through the drill line using a paper cutter (JDC-1-10 or JDC-1-12 with safety protection from the Thwing-Albert Instrument Co. instrument, 10960 Dutton Road, Philadelphia, PA, 19154 ) to make 4 separate materials. Make sure that batteries 1 and 3 are still identified for the test in the machine direction and batteries 2 and 4 are identified for the cross direction test. Cut two 1-inch-wide strips in the machine direction in stacks 1 and 3. Cut two 1-inch-wide strips in the cross direction of stacks 2 and 4. There are now four 1-inch-wide strips for the tension test in the direction of the machine and four strips of 1 inch of P867 width for the tension test in the transverse direction. For these samples of finished product, the eight strips of 1 inch wide are five widths of useful units (also called leaves). For unconverted material and / or reel samples, cut a 15-inch by 15-inch sample that is a thickness of 8 sheets from a region of interest of the sample using a paper cutter (JDC-1-10 or JDC -1-12 with safety protection from Thwing-Albert Instrument Co., 10960 Dutton Road, Philadelphia, PA, 19154). Make sure that a 15-inch cut runs parallel to the machine direction while the other runs parallel to the cross direction. Make sure that the sample is conditioned for at least 2 hours at a relative humidity of 48 to 52% and within the temperature range of 22 to 24 ° C. The preparation of the sample and all aspects of the stress test should also be carried out within the confines of the constant temperature and quarter of humidity. For this 15-inch by 15-inch, preconditioned sample, which is 8 sheets thick, cut four 1-inch by 7-inch strips with the dimension 7 inches long and run parallel to the machine's direction. Point out, that these samples are P867 spool or material samples not converted in the machine direction. Cut four additional 1-inch by 7-inch strips with the 7-inch-long dimension running parallel to the transverse direction. These samples are designated as spool samples and material not converted in the transverse direction. Make sure all previous cuts are made using a paper cutter (JDC-1-10 or JDC-1-12 with safety shield from Thwing-Albert Instrument Co., 10960 Dutton Road, Philadelphia, PA, 19154). There are now a total of eight samples: four 1-inch by 7-inch strips that are 8 sheets thick and the 7-inch dimension that runs parallel to the machine direction and four 1-inch by 7-inch strips that are 8 sheets of thickness with the dimension of 7 inches and runs parallel in the transverse direction.

OPERATION OF THE TENSION TESTER For the actual measurement of the tensile strength, using the Thwing-Albert Intelect II standard tension tester, Standard Tensile Tester (Thwing-Albert Instrument Co., 10960 Dutton Rd., Philadelphia, PA, 19154) . The flat surface clamps are inserted into the unit where the tester is calibrated.

P8S7 according to the instructions given in the Thwing-Albert Intelect II operation manual. Adjust the crosshead speed of the instrument to 4.00 inches / minute and the first and second lengths to 2.00 inches. The breaking sensitivity should be adjusted to 20.0 grams and the sample width should be adjusted to 1.00 inches and the thickness of the sample to 0.025 inches. A load cell is selected in such a way that the predicted stress result for the sample being tested is between 25% and 75% of the range in use. For example, a 5000 gram load cell can be used for samples with a predicted voltage range of 1250 grams (25% of 5000 grams) and 3750 grams (75% of 5000 grams). The tension tester can also be adjusted in the 10% range with the 5000 gram load cell so that samples with predicted stresses of 125 grams to 375 grams must be tested. Take one of the tension strips and place one end of it in a clamp of the tension tester. Place the other end of the paper strip in the other clamp. Make sure that the dimension along the strip is running parallel to the sides of the tension tester. Also make sure that the strips P867 They are not hung on either side of the two clamps. In addition, the pressure of each of the clamps must be in full contact with the paper sample. After inserting the paper test strip into the two clamps, the tension of the instrument can be monitored. If it shows a value of 5 grams or more, the sample is too tight. Conversely, if a period of 2-3 seconds elapses after starting the test before any value is severe, the tension strip is too loose. Start the voltage tester as described in the manual of the voltage tester instrument. The test is finished after the crosshead automatically runs to its starting position. Read and record the voltage load in grams units of the scale of the instrument or the digital panel meter to the nearest unit. If the reset condition is not automatically performed by the instrument, it must be necessary to make the necessary adjustment to adjust the clamps of the instrument to its initial positions. Insert the next paper strip into the two clamps as described above and obtain a tension reading in units of grams. Get the readings of P867 tension of all paper test strips. It should be noted that the readings should be rejected if the strip slips or breaks at the edge of the clamps or near them while the test is performed.

CALCULATIONS For the four strips of finished product one inch wide, in the direction of the machine, add the four recorded, individual voltage readings. Divide this sum by the number of strips tested. This number should normally be four. Also divide the sum of recorded voltages between the number of useful units per voltage strip. This is normally five for both single sheet and two sheet products. Repeat this calculation for the strips of finished product in the transverse direction. For unconverted material or spool samples cut in the machine direction, add the four recorded, individual voltage readings. Divide this sum by the number of strips tested. This number should normally be four. Also divide the sum of recorded voltages between the number of useful units per voltage strip. This is normally eight. Repeat this calculation for spool or unwrapped sample paper strips in the address transversal All results are in units of gram / inch (g / inch).

EXAMPLES The following examples are offered to illustrate the practice of the present invention. The examples are proposed to aid in the description of the present invention, but, in no way should they be construed as limiting the scope thereof. The present invention is limited only by the appended claims. First, a Northern Coniferous Wood (NSK) Kraft pulp of approximately 3% consistency is made using a conventional pulping apparatus and passed through a tube of material to the main box of the Fourdrinier. In order to impart a temporary wet strength to the finished product, a 1% dispersion of Co-BOND 1000 is prepared and added to the tube of NSK material at a rate sufficient to distribute 1% Co-BOND 1000 based on the dry weight of the NSK fibers. The. The absorption of the temporary wet strength resin is improved by passing the treated pulp through an in-line mixer. The NSK pulp is diluted with water to P8S7 approximately 0.2% consistency in the blade pump. An aqueous pulp of eucalyptus fibers of about 3% by weight is made using a conventional pulping apparatus. The eucalyptus is passed through a tube of material to another blade pump where it is diluted with water to a consistency of approximately 0.2%. The NSK and eucalyptus pulps are directed to a multi-channel main box suitably equipped with stratification plates to hold the streams as separate layers until unloading in a Fourdrinier travel mesh. A main box of three cameras is used. The eucalyptus pulp containing 80% of the dry weight of the final paper is directed to the chambers leading to each of the two outer layers, while the NSK pulp comprising 20% of the dry weight of the final paper is It directs to a chamber that leads to a layer between the two layers of eucalyptus. The NSK and eucalyptus pulps are combined in the discharge in the main box in a composite pulp. The composite pulp is discharged into the travel Fourdrinier mesh and drained by a deviator and vacuum boxes. The embryonic wet weave is transferred from the P867 Fourdrinier mesh, at a fibrous consistency of about 15% at the point of transfer, to a pattern forming fabric of a 5-drapery satin weave configuration having 84 mono filaments in the machine direction and 76 mono filaments in the direction crosswise to the machine per inch, respectively, and approximately 36% knuckle area. Additional dewatering is achieved by vacuum-assisted drainage until the weft has a fibrous consistency of approximately 28%. While remaining in contact with the pattern forming fabric, the patterned pattern is pre-dried by blowing air through to a fibrous consistency of about 62% by weight. The weft is semi-dry then adhered to a Yankee dryer surface 10 feet in diameter by means of a spray creping adhesive comprising an aqueous solution of 0.25% of the composition selected from the following table. The compositions selected represent Examples 1-8. Examples 1, 2 and 3 correspond to polyvinyl alcohol and mixtures of polyvinyl alcohol and polyamide-epichlorohydrin resin described in the prior art. Examples 4, 5, 6, 7 and 8 are compositions according to the present invention.

The experiment is designed as an experiment designed for a mixture of three variables and the compositions are selected for application to the Yankee dryer according to a random sequence.

Polyvinyl alcohol is Airvol 540 obtained from Air Products Company of Allentown, PA. The cationic starch is RediBOND 5320R obtained from the National Starch and Chemical Company of Bridgewater, New Jersey. The polyamide-epichlorohydrin resin is Kymene 557HR obtained from Hercules Inc. of Wilmington, DE. The creping adhesive, selected, is sprayed P867 on the Yankee surface through a spray vessel equipped with three separate nozzles across the width of the dryer. -The nozzles are of model number 650050 obtained from Spraying Systems Inc. of Wheaton, IL. The nozzles are directed towards the surface of the dryer and are located about 25 centimeters from the surface. The arm is placed approximately 1 meter from the point at which the semi-dry frame comes into contact with the Yankee. The arm is pressurized to approximately 100 psi. At this pressure level, the spray nozzles distribute the creping adhesive at a rate of about 1.7 pounds / ton of creping adhesive solids based on the dry weight of the screen. The fibrous consistency is increased to approximately 96% before the weft was creped dry from the Yankee with a scraper blade. The scraper blade has a skew angle of approximately 25 degrees and is positioned with respect to the Yankee dryer to provide an impact angle of approximately 81 degrees. The creping percentage is adjusted by approximately 18% when operating the Yankee dryer at approximately 800 fpm (feet per minute) (approximately 224 meters per minute), while the Dry weft is formed on the roller at a speed of 656 fpm (201 meters per minute). A web tensiometer placed in the web traveling between the creping blade and the reel detects the tension in the web, to measure the degree of adhesion of the web to the dryer. The finished weft becomes a densified, crepe-patterned, single-sheet tissue paper product, three layers of approximately 18 pounds per 3000 square feet, basis weight. The results of the measurement of the tension of the frame for each adhesive formulation are modeled using a multivariate regression. All terms of first and second possible orders using the three input variables are included in the regression, but terms with less than 95% probability of meaning are removed in a gradual manner until all remaining terms are statistically significant to a 95% confidence interval. This results in the following raster tension model: Weft tension =% PVOH X 0.26+% Cationic Starch X 0.31 +% PAE X 0.81-% PAE X% PVOH X 0.70 -% PAE X% of Cationic Starch X 0.56, in which% of PVOH,% of Cationic Starch,% P867 of PAE, represents the values for the percentage of polyvinyl alcohol, cationic starch and polyamide-epichlorohydrin resin, respectively, which make up the solid fraction of the aqueous dispersion applied as the creping adhesive. Using this model, the following values of tension of the plot correspond to the formulations of adhesive of the examples: The above results indicate that the dispersions according to the invention (examples 4, 5, 6, 7 and 8) produce higher weft adhesion than the prior art dispersions of examples 1, 2 and P867 3. Example 8 exhibits a particularly good balance of adhesion and doctoracy. P867

Claims (10)

1. CLAIMS: 1. An aqueous dispersion useful as a creping adhesive, comprising cationic starch, the cationic starch has between about 0.001 and about 0.2 cationic substituents per anhydroglucose unit of starch, the aqueous dispersion contains from about 90% to about 99.9% of water.
2. 2. The aqueous dispersion according to claim 1, further comprising a polyvinyl alcohol, the cationic starch comprises from about 10% to about 70% of the dry weight of the dispersion and the polyvinyl alcohol comprises from about 30% to about 90% of the dry weight of the dispersion.
3. 3. The aqueous dispersion according to claim 1, further comprising a water-soluble, cationic, cationic, polyamide-epihalohydrin resin, the cationic starch comprises from about 50% to about 90% of the dry weight of the dispersion and the cationic polyamide-epihalohydrin resin comprises from about 10% to about 50% of the dry weight of the dispersion. .
4. The aqueous dispersion according to the claim P867 3, which further comprises a polyvinyl alcohol, the cationic starch comprises from about 10% to about 70% of the dry weight of the dispersion and the cationic polyamide-epihalohydrin resin comprises from about 5% to about 40% of the dry weight of the dispersion and the polyvinyl alcohol comprises from about 20% to about 85% of the dry weight of the dispersion.
5. The aqueous dispersion according to any of the preceding claims, wherein the polyvinyl alcohol has a degree of hydrolysis of between about 80% and about 95% and the cationic substituents of the cationic starch are selected from the group consisting of tertiary aminoalkyl ethers , alkyl ethers of quaternary ammonium and mixtures thereof.
6. The aqueous dispersion according to claims 3 or 4, in which the water-soluble thermosetting polyamide-epihalohydrin resin is the reaction product of an epihalohydrin and a polyamide precursor containing the recurrent group -NH (CnH2nHN ) x-CORCO-where n and x are each 2 or more and R is a saturated aliphatic chain having 3-10 carbon atoms.
7. 7. A process for creping tissue paper, comprising: a) applying to a rotating creping cylinder an aqueous dispersion comprising from about 90% to about 99.9% water and from about 10% to about 0.1% solids, wherein the solids comprises a cationic starch having from about 0.001 and about 0.2 cationic substituents per unit of anhydroglucose starch; b) pressing a tissue paper web against the creping cylinder to effect adhesion of the web to the surface of the barrel; and c) dislodging the creping cylinder web by contact with a scraper blade.
8. A process for creping tissue paper according to claim 7, wherein the solids comprise between about 50% to about 90% of the cationic starch and the solids are additionally comprised of a cationic thermosetting resin of polyamide-epihalohydrin, soluble in water at a level from about 10% to about 50% of the solids.
9. 9. A process for creping tissue paper according to claim 7, wherein the solids comprise between P867 about 10% to about 70% of the cationic starch and the solids are additionally comprised of a cationic thermosetting resin of polyamide-epihalohydrin, soluble in water at a level from about 5% to about 40% and from about 20% to about 85 % of a polyvinyl alcohol. The process according to claim 9, wherein the cationic water-soluble thermosetting polyamide-epihalohydrin resin comprises the reaction product of an epihalohydrin and a polyamide precursor containing the recurrent group -NH (CnH2nHN) x-CORCO- wherein n and x are each 2 or more and R is a saturated aliphatic chain having 3-10 carbon atoms.P867