CA2176898C - Crosslinkable creping adhesive formulations - Google Patents

Abstract

Disclosed are adhesive formulations as creping process aids for producing an absorbent creped cellulosic sheet having a high level of surface-perceived softness that comprises continuously forming a web of cellulosic papermaking fibers, adhering said web to a thermal drying means by means of adhesive compositions comprising polymers having at least one primary or secondary amine group in the backbone such as chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine and polyaminoamide in combination with crosslinking agents such as dialdehydes or zirconium compounds having a valence of plus four including ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartate and creping said treated web from said thermal drying means. In the method for producing the absorbent creped cellulosic sheets, the zirconium crosslinking agent is advantageously applied directly and separately on the Yankee dryer at the time the base polymer is applied to the surface. Alternatively, when using dialdehydes, the dialdehydes are mixed with the base polymer just prior to application to the Yankee dryer surface without having the crosslinking reaction take place with the base polymer prior to reaching the heated Yankee surface. These sheets are useful in the manufacture of tissue and towel.

Description

"~7-MRY-1996 16~49 MRTHYS 8 SQUIRE 0171 830 0001 P.06i62 CROSSLINKABLE CREPING ADHESIVE FORMULATIONS
This invention relates to papermaking. More particularly, this invention is concerned with the°manufacture of grades of paper that are suitable for use in paper toweling, napkins, facial tissue, and bathroom tissue by methods that include creping utilizing novel adhesives used as creping process aids.
BACKGROUND OF THE INVENTION
In the manufacture of tissue and towel products, a common step is the ereping of the product. This creping is done to provide desired aesthetic and performance propetties to the product_ Many of the aesthetic properties of tissue and towel products rely more upon the perceptions of the consumer than on properties that can be measured quantitatively. Such things as softness, and perceived bulk are not easily quantified, but have significant impacts on consumer acceptance. Since many of the properties of tissue and towel products are controlled or are at least influenced by the creping process it is of interest to develop methods for controlling the creping process. Although the creping process is not well understood, it is known that changes in the process can result in significant changes in the product properties. A
need exists to provide a method for influencing the creping process by allowing the control of the adhesion of the tissue or towel substrate to the surface from which it is creped, most usually large cylindrical dryers known in the industry as Yankee dryers.
Paper is generally manufactured by suspending cellulosic fibers of appropriate length in an aqueous medium and then removing most of the water to form a web.
The paper derives some of its structural integrity from the mechanical arrangement of the cellulosic fibers in the web, but most by far of the paper's strength is derived from hydrogen bonding which links the cellulosic fibers to one another. With paper intended for use as bathroom tissue, the degree of strength imparted by this interfiber bonding, while necessary to the utility of the product, results in a lack of perceived softness that is inimical to consumer acceptance. One common method of increasing the perceived softness of bathroom tissue is to crepe the paper. Creping is generally effected by fixing the cellulosic web to the surface of a dryer e.g. a drum dryer such as a Yankee drum thermal drying means with an adhesive/release agent combination and then scraping the web off of the surface by means of a crepiag 17-MAY-1996 16:49 MATHYS 8~ SQUIRE 0171 830 0001 P.07i62 blade. Creping, by breaking a significant number of interfiber bonds, increases the perceived softness of resulting bathroom tissue product.
In the past, common classes of thermosetting adhesive resins which have been used as creping adhesives have been represented by poly (aminoamide)-epichlorohydrin polymers (hereinafter referred to as PAE resins), such as those polymers sold under the tradenames Kymene, Rezosol, Cascamid, and Amrezs. Each of these materials represent products sold respectively by the Hercules Chemical Company, the Houghton Company, the Borden Company, and Georgia-Pacific.
Although these materials are now in commercial use, our novel adhesive formulations are environmentally friendly and have lowct in-use cost.
This invention provides adhesion.which is equal or better than the adhesion characteristics available through the use of PAE resins but having none of the attendant environmental problems associated with the halogen moiety. The halogen free, particularly chloride free, creping adhesives of this invention prevent or inhibit chloride or halogen induced corrosion of the dryer, e.g. Yankee drum, surface and, also, are friendly to the environment and have a lower in use cost.
Obtaining and maintaining adhesion of tissue and towel products to dryers is an important factor in determining crepe quality. Inadequate adhesion results in poor or non-existing creping, whereas excessive adhesion may result in poor sheet quality and operational difficulties. Traditionally, creping adhesives alone or in combination with release agents have been applied to the surface of the dryer in order to provide the appropriate adhesion to produce the desired crepe. Various types of creping adhesives have been used to adhere fibrous webs to dryer surfaces such as Yankee dryers. Some examples of prior art creping adhesives are disclosed in U.S.
Patents 4,886,579; 4,528,316 and 4,501,640.
U.S. Patent No. 5,246,544 describes a creping adhesive that provides the ability to control coating mechanical properties and adhesion, and which can be more easily removed from dryer surfaces. The adhesive system described in said patent provides high adhesion of a fibrous web to dryer surface with low "friction".
Having low friction means that the fibrous web can easily be removed from the dryer surface.
Other references of interest include U.S. Patents 5,232,553 and 4,684,439. All the prior art patents are of interest but do not disclose polymers having at least one primary or secondary amine group in the backbone such as chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine, polyaminoamide and etc., in 17-MAY-1996 16:50 MRTHYS 8 SQUIRE 0171 830 0001 P.08i62 combination with the dialdehydes or the zirconium crosslinking compounds having a valence of plus four such as ammonium zirconium carbonate, zirconium acctylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate. These patents also do not relate to creping adhesives or the creping of tissue and towel from a Yankee dryer. U.S. Patents 5,374,334 and 5,382,323 relate to adhesives reacted with the erosslinking agent prior to establishing contact with the dryer surface. In our novel process the crosslinking agents are either charged to the dryer surface at the same time as the adhesive polymer or are mixed shortly prior to charging the polymer and crosslinking agent mixture to the Yankee surface without reacting the crosslinking agent with the polymer. ' SUMMA1ZY OF TIIE IN'V'ENTION
The present invention provides creping adhesives which are friendly to the environment giving off no chlorine compound pollutants, can be applied directly to the dryer, e.g. Yankee from aqueous solution and are substantially less costly than the presently available creping adhesives. The present invention provides an improved creping adhesive which provides the ability to readily control glass transition (Tg) and adhesion and which can be more easily removed from dryer surfaces.
An advantageous feature of the present invention is that the adhesion properties of spec types of polymers or copolymers (hereinafter referred to as base polymers) can be systematically changed by varying the amount of erosslinking that may occur when the base polyraer is dried onto the surface of a Yankee dryer with the zirconium or dialdehyde crosslinking agents. Because crosslink density influences the mechanical properties (i.e., modulus, brittlencss, Tg), this permits the adjustment of adhesion/release of the fibrous substrate onto the surface of the dryer. Base polymers having at least one primary or secondary amine groups in the backbone such as chicosan, polyvinylamine, polyvinyl alcohol-vinyl amine, polyaminoamide and etc., crosslinked with dialdehydes or zirconium compounds having a valence of plus four produces an adhesive friendly to the environment and which is much less costly than the PAE resin available on the market as discussed in the background section.
The invention also relates to a process for applying such base polymers without pre-17-MRY-1996 16~50 MRTHYS 8 SQUIRE 0171 830 0001 P.09i62 crosslinking to achieve adhesion control on the paper machine through spray application. This invention also relates to creped fibrous webs, creped tissue and creped towel and a process for the manufacturing of these paper products utilizing the novel adhesives of~this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described in greater detail with reference to preferred embodiments and with the aid of the accompanying drawings which illustrate the application of the invention in a papermaking process employing a Yankee dryer as illustrative of the drying means (although it should be understood that the invention is also applicable to other drying means, e.g. through air dryers) and wherein:
Figure 1 illustrates a paper making process.
Figure 2 illustrates in detail the Yankee dryer employed in the scheme and the position from which the base polymer and the crosslinking agent, and if necessary, the softener can be sprayed on the Yankee or the web.
Figure 3 illustrates the effect of glyoxal crosslinking agent on polyvinyl alcohol (PVOIT) Yankee adhesion, as measured by peel force, for different molecular weight and hydrolysis degrees.
Figure 4 illustrates the effect of glyoxal crosslinking agent on polyvinyl alcohol-vinyl amine copolymer adhesion and blend with unfunctlonalized polyvinyl-alcohol, as measured by peel force with and without softener.
Figure 5 illustrates the GMT ( grams/3 inches ) versus the glyoxal level incorporated into the base polymer such as polyvinyl alcohol-vinyl amine copolymer, and blend with unfunctionalized polyvinyl alcohol, with and without softener.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, a method is provided for producing a highly absorbent, eellulosic sheet having a high level of perceived softness that comprises continuously a) preparing an aqueous dispersion of cellulosic papermaking fibers, b) forming a web of said cellulosic papermaking fibers, c) adhering the web to a dryer surface such as a Yankee dryer with base polymers wherein suitably the base polymer can have both primary and secondary amine groups or a mixture of primary and secondary amine groups. Representative base polymers include polyvinyl alcohol-vinyl amine copolymers, ehitosan, polyvinylamine and polyaminoamide. The base polymers are c~slinked with materials such as dialdehydes or zirconium compounds having a valence of plus four. The base polymers having at least one primary or secondary amine group or a mixture of primary and secondary amine groups are prepared according ~ the methods disclosed in the following U.S. Patents:
5,155,167;
5,194,492; 5,300,566; 4,574,150; 4,786,087; 4,165,433; 3,892,731; 3,879,377;

2,926,154 and 2,926,116. The cellulosic sheet was creped from the Yankee dryer by a creping blade thus providing a higher degree of perceived softness. Suitable paper products obtained utilizing the novel adhesives include single and mufti ply tissue and towel.
Useful polyaminoamides have the following rating unit struct~rre:
O O
a wherein R, and R2 have two to eight aliphatic carbon atoms and R3 has two to six carbon atoms.
The preferred polyvinyl alcohol and polyvinylamine copolymer has the following structure:

OH NHZ
n where m and o have values of about I to 99 and about 99 to 1. Advantageously the values of m and n are about 1 to 99 and about 2 to 20. The polyvinyl alcohol-virryl amine copolymer can have impurities which comprise the unhydrdized starting product. The structure of an impure product is disclosed in U.S. Patents 5,300,566 and 5, 194, 492. The crosslinking agent sprayed with the polyvinyl alcohol-vinyl amine copolymer as shown in Figure 2 at position 51 is a dialdehyde such as glyoxal or glutaraldehyde and etc., or a zirconium compound having a valence of plus four such as ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulphate, zirconium phosphate, potassium zirconium carbonate, 17-MAY-1996 16:51 MATHYS 8 SGlUIRE 0171 B30 0001 P.11i62 zirconium sodium phosphate and sodium zirconium tartrate. The zirconium crosslinking agents and polyvinyl alcohol-vinyl amine base polymer are sprayed separately at the same time on the Yankee surface. The dialdehydes are mixed with the base polymer just prior to spraying so that the dialdehyde and base polymer have no practical chance to react prior to reaching the heated Yankee surface. The crosslinldng agent and base polymer are reacted directly oa the Yankee surface.
Spraying the adhesive on the Yankee is the best mode of application of the adhesives.
Suitable dialdehydes are glyoxal, malonic, succinic, and glutarie dialdehyde.
Suitably these aldehydes can be represented by the following structural formula:
O O
H-C-(CH~o-C-H
wherein n is an integer having a value of 0 to 3. The preferred aldehydes are glyoxal and gIutaraldehyde. In some applications for the manufacture of tissue and towel, suitable softeners are utilized. The softeners are sprayed on the web as shown in Figure 2 from position 52 or 53.
The novel adhesives are environmentally friendly and are very capable of ready application to the Yankee surface from aqueous solution. Additionally the adhesives are substantially less expensive than present PAE resin products.
For the sake of simplicity, the invention will be described immediately herein below in the context of a conventional dry crepe wet-forming process. A
schematic drawing depicting a process configuration is set forth in Figure 1.
The paper products, such as tissue and towel, of the present invention may be manufactured on any papermaking machine of conventional forming configurations such as fourdrinier, twin-wire, suction pressure roll or crescent forming configurations. The forming mode is advantageously water or foam. Figure I illustrates an embodiment of the present invention wherein a machine chest 50 is used for preparing furnishes that may mutually be treated with chemicals having different functionality depending on the character of the various fibers, particularly fiber length and rnarseness. The furnishes are transported through conduits 40 and 41 where the furnishes are delivered to the headbox of a crescent forming machine 10.
This Figure 1 includes a web-forming end or wet end with a liquid permeable foraminous 2176~9~
17-MRY-1996 16:51 MATHYS 8 SQUIRE 01'71 830 0001 P.12i62 support member 11 which may be of any conventional conSgura~on. Foraasinous support member 1 i may be constructed of any of several brown materials including photo polymer fabric, felt, fabric or a synthetic filament woven mesh base with a very 5ne synthetic fiber hart attached to the mesh bate. The foraminous support member 11 is supported in a conventional manner on rolls, including press roll 15 and couch roll or pressing rou 16.
Forming fabric 12 is supported on rolls 18 and 19 which're positioned relative to the press roll I S for pressing the press wire 12 to converge on the foraruinous support member 11 at the ~ylindricai press roD I 5 at an acute eagle relative tn the foraminous support member I 1. The foraminous support member I 1 and the wire 12 move in the same direction and at the same speed which is the same direction of rotation of the pressure roll 1 S. ?he . .
pressing wire 12 and the foraminous support member 11 comrerge ai an upper surface of the farming roll 15 to form a wedge-shaped space or nip into which twv jets of water or foamed-liquid fiber dispersion is pressed between the pressing wire 12 and the foraminous support member 11 to force fluid through the wire 12 into a saveall Z2 where it is collected for reuse in the process.
A wet nascent web W formed in the process is carried by the foraminous support member 11 to the pressing roll 16 where the wet nascent web W is transferred to the drum 26 of a Yankee dryer. Fluid is.pressed from the wet web W by pressing roll I 6 as the web is transferred to the drum 26 of the Yankee dryer where it is dried and creped by means of s creping blade 27. The finished web is collected on a take-up roll 28.
A pit 44 is provided for collecting water squeezed from the nascent web W by the press roll 16 and the Uhle box Z9. The water collected in the pit 44 may be collected into a flow line 45 for separate processing to remove surfactant end fibers from the water and to Peg re~.Ycting of the water back to the papennalang machine 10. The liquid, suitably foamed Liquid, is collected from the furnish is the saveall 22 and is returned through line 24 to a recycle process generally indicated by box 50.
Dewatering of tire wet web is provided prior to the thermal drying ope,~a~
typically by employing a nonthemral dewatering mesas. ?he na~nthem~l dewatering step is usually accomplished by various mearu for imparting mechanical oompaction to the web, such as . _ vacuum boxes, slot boxes, coscting press rolls, or combittarions thereof For purposes of illustration of the method of this invention, the wet web may be dewatered by Subjecting same to a series of vacuum boxes and/or slot boxes. Thereafter, the web may be fruther dewatered by subjecting same to the compressive forces exerted by nonthermal dewaxering means such as, for e.~cample, utilizing roll 15, followed by a pressure roll 16 coa~cting with a thermal drying means. The wet web is carried by the foraminous conveying means 11, 12 through the nonthermal dewatering means, and is dewatered to a fiber consistency of at least about 5% up to about 50~/0, preferably at least 15% up to about 45%, and more preferably to a fiber consistency of approximately 40%.
The dewatered web is applied to tire surface of thermal drying means, preferably a thermal drying cylinder such as a Yankee drying cylinder 26, employing the dialdehyde or zirconium crosslinking agent having a valence of plus four with the polyvirryl alcohol-vinyl amine copolymer. Under the definition of "Yankee" is included all large cast-iron drying cylinders some of which may be ceramic coated on which towel, tissue, wadding, and machine-glazed papers are among the grades produced Diameters typically range from 10-20 feet and widths can approach 300 inches. A typical diameter for a Yankee drying drum is 12 feet.
Speeds in excess of 6000 ft/min. at weights greater than 380,000 pounds are not uncommon.
Dryem typically incorporate a center shaft and are supported on journals by two large antifriction bearings. Steam, up to 160 psig (Code limitation for cast iron unfired pressure vessels) is supplied through the front-side journal and exhausted, along with condensate, through the back-side journal. A typical steam pressure is 125 psig. Pressure rolls 16, one or two usually loaded between 200 and S00 pounds/linear inch, are employed to press the sheet uniformly against the shell face. The sheet is removed from the dryer several quadrants away, having been imparted with properties characteristic of the desired paper product Adhesion of the dewatered web to the cylinder surface is facilitated by the mechanical compressive action exerted thereon, generally using one or more press rolls 16 that form a nip in combination with thermal drying means 26. This brings the web into more uniform contact with the thermal drying surface.
Since we prefer to use high adhesion creping, to quantify the degree of adhesion, we define adhesi~ as the force in grams required to peel a 12 inch wide sheet off the creping cylinder at a 90 degree angle with the creping blade in the off load position.
We have fovrrd that using the creping adhesive of this invention, it is possible to control adhesion such that the junction between the sheet and Yankee (26) exhibits relatively high adhesion compared to 1'7-MRY-1996 16: 52 MRTHYS & SDU I RE 01'71 830 0001 P. 1462 conventional adhesives which include PAE resins. I~gb ad~ion level is preserved when our crosslinkable adhesive formulations are used as the creping process aids in tire presence of softener and debonder Specifically, when softener is used in the range of one (1 ) to about tea (10) pounds per ton, adhesion is good as defined by the peel force of about 300 to about 900 grams per 12 inches, when using a papetmabng machine having a speed of less than one hundred fifty feet per minute (150 ft/minute): Generally, when softener is added, adhesion is decreased Unlike com~entional adhesives of the PAE type and the like, utilization of our crosslinkable adhesive formulation in conjunction with softener, allows one to minimize the difference between air and Yankee side friction of the creped product while preserving overall low friction, all of which promote high quality crepe structure required for good tissue and towel softness.
Alternatively adhesion can be indire~ly measured as sheet tension with the creping blade in on-load position Sheet tension should be in the range of 600 -1,500 grams per 12 inches. 'Ihe sheet tension is measured by the transducer idler roll positioned prior to take-up roll 28. If paper raschine speed, basis weight, furnish refining and other operational parameters are kept constant, then sheet tension is a fvmction of adhesion only.
Figure 2 illustrates the drying and creping of the ceUulosic web to produce tissue arid towel According to our process, both one ply and multi-ply towel and tissue are produced According to the process of the invention, the novel adhesives each comprising base polymer and crosslinlang agent are sprayed direcdy on the Yankee (26) at position S I.
In the event it is desired to use softeners, these are sprayed on the air side of the web from position 52 or 53 as shown in Figure 2. When using the zirconium crosslinlang agent then both 8ie base polymer and the crosslinbng agent are sprayed separately but al~st simultaneously on the heated Yankee surface.
The various components of the adhesive formulation, may all be dissolved, dispersed, suspended, or emulsified in a liquid carrying fluid It should be noted that the crosslinking agents in our process are either sprayed directly on the Yankee surface with the base polymer or in case of the dialdehydes are mixed with the base polymer just prior to sprayring ?his liquid wr71 generally be a non-toxic solvent such as water. The liquid componem is ususUy present in an amount of 90 to 99'/e by weight of the total weight of the creping adhesive. The pH of the adhesive when it is applied to the desired surface in the papermabag operation will normally be about 7.5 to 11. The solvent preferably consists essentially or completely of water.
If other types of solvents are added, they are generally added in small amounts.
Referring to the drawing in Figure 2, this represents one of a number of possible configurations used in processing tissue and towel products. In this particular arrangement, the transfer and impression fabric carries the formed, dewatered web W around turning roll 15 to the nip between press roll 16 and Yankee dryer 26. The fabric, web and dryer move in the directions indicated by the arrows. Tfie eamy of the web to the dryer is well around the roll from creping blade 27 which, as schematically indicated, crepes the traveling web fiom the dryer as indicated at 27. The creped web W exiting from the dryer is wound into a soft creped tissue, or towel at roll 28. To adhere the nascent web W to the surface of the dryer, a spray 51 of adhesive is applied to the surface ahead of the nip between the press roll 16 and Yankee 26.
Alternately, the spray may be applied to the traveling web W directly as shown at 53. Suitable apparatus for use with the present invention are disclosed in U.S. Patents 4,304,625 and 4,064,213.
This illustration does not incorporate all the possible configurations used in presenting a nascent web to a Yankee dryer. It is used only to describe how the adhesives of the present invention can be used to promote adhesion and thereby influence the crepe of the product. The present invartion can be used with all other lrnown processes that rely upon creping the web from a dryer surface. In the same manner, the method of application of the adhesive to the surface of the dryer or the web is not restricted to spray applications, although these are generally the simplest method for adhesive application.
The present invention is useful for the preparation of fibrous webs which are creped to increase the thickness and bulk of the web and to provide texture to ~e web.
The invention is particularly useful in the preparation of final products such as facial tissue, toilet tissue, paper towels, and the like. The fibrous web can be formed from various types of wood pulp based fibers which are used to make the above products such as hardwood kraft fibers, softwood kraft fibers, hardwood sulfite fibers, softwood sulfite fibers, high yield fibers such as chemo-thermo-mechanical pulps (CT11~), thermomechanical pulps (T11~) or refiner mechanical pulps (RMP). Furnishes used may also contain or be totally comprised of recycled fibers (i. e., secondary fibers). The fibrous web, prior to application to the Yankee dryer, usually has a water content of 40 to 80 wt. %, more preferably 50 to 70 wt. %. At the creping stage, the ~~T-MRY-1996 16:52 MRTHYS & SQUIRE 0171 830 0001 P.16i62 fibrous web usually has a water content of less than 7 wt. %, preferably less than 5 wt. %.
The final product, after creping and drying, has a basis weight of 7 to 30 pounds per ream.
The non-self crosslinkable base polymer of the present invention called the base polymer, has at least one primary or secondary amine groups in the backbone such as chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine, polyarninoamide and etc., or combinations thereof and the crosslinking agents are dialdehyde or zirconium compounds having a valence of plus four. Suitable dialdehydes include glyoxal, malonic dialdehyde, suecinic dialdehyde and glutaraldehyde. Suitable zirconium crosslinking agents include ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.
The non-self-crosslinkable base polymer should be present in the creping adhesive in an amount sufficient to provide the desired results in the creping operation. If it is intended to spray the creping adhesive onto the surface of the Yankee dryer, the creping adhesive should have a viscosity low enough to be easily sprayed yet high enough to provide a sufficient amount of adhesion. When the creping adhesive is sprayed onto the surface of the Yankee dryer, it should have a total solids content of about 0.01 to 0.5, preferably 0.03 to 0.2% by weight based on the total weight of the fiber. The solids content is constituted primarily by the base polymer and the dialdehyde or zirconium crosslinldng agent. The zirconium crosslinking agent having a valence of plus four is sprayed separately on the Yankee surface and only comes in contact with the base polymer on the heated Yankee surface, whereby the combined action of drying and heating effect crosslinking required for adhesion.
The crosslinking agent should be present on the Yankee surface in the cteping adhesive formulation in an amount sufficient to provide changes in the mechanical properties of the base polymer once the solution has been evaporated and the polymer crosslinked. As the level of crosslinking increases, the mechanical properties change with the crosslink density. Increased crosslinking generally will increase the Tg, increase the brittleness, hardness, and provide different responses to mechanical stresses than unerosslinked polymers.
Obtaining the appropriate crosslink density will depend not only on the relative concentration of added crosslinking agent but also on the molecular weight of the polymer. In general, as the molecular weight of the starting polymer increases, the amount of crosslinking agent necessary to provide particular levels of final properties (i.e., Tg, brittleness, etc.) decreases. A discussion concerning the relationship between Tg and crosslinlong of polymers is contained in the article by Stutz et al., Journal of Polymer Science. 28, 1483-1498 ( 1990).
In our process the ratio of the base polymer to the crosslinldng agent can be varied widely. The function of the crosslinking agent is to control adhesion. The weight ratio of the crosslinlang agent to base polymer may go up to 4:1. The preferred ratio is about 0.05:1 to about 2:1. The base polymer can be a homopolymer or a copolymer. It should be noted that in our process all the crosslinking was activated on the heated Yankee surface.
While the base polymer and crosshnlang agent are the major "active"
ingredients of the present invention, other materials can be incorporated with beneficial results. Materials can be added to modify the mechanical properties of the crosslinked base polymers.
Some of these materials may actually be incorporated into the crosslinked polymer. Examples would include glycols (ethylene glycol, propylene glycol, etc.), polyethylene glycols, and other polyols (simple sugars and oligosaccharides). Other components can be added to modify interfacial phenomena such as surface tension or wetting of the adhesive solution.
Nonionic surfactants such as the octyl phenoxy based Triton (Rohm & Haas, Inc.) surfactants or flte pluronicTM or TectronicTM (BASF Corp.) surfactants can be incorporated in the present invention to improve surface spreading or wetting capabilities. M'meral oils or other low molecular weight hydrocarbon oils or waxes can be included to modify interfacial phenomena and thereby control adhesion.
The non-self crosslinking base polymer, polymer modifiers, surfactants, and anti-corrosion additives, will all be dissolved, dispersed, suspended, or emulsified in a liquid canying fluid This liquid will usually be a non-toxic solvent such as water.
In our novel process the zirconium crosslinlang agents such as ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate crosslinking ag~ts were sprayed directly on the Yankee or alternately the dialdehyde was added to the adhesive formulation just prior to spraying on the Yankee surface to avoid reaction with the base polymer and the crosslinking agent prior to reaching the heaxed Yankee surface.

2176.898 ~7-MRY-1996 16:53 MRTHYS 8~ SQUIRE 0171 830 0001 P.18i62 Nitrogenous softeners/debonders can suitably be added in the paper manufa~g process. The softener may suitably be added with the fu~sh, but is preferably sprayed from position 53 as showrr?ia Figure 2, or also sprayed to the sheet while the sheet is on the Yankee as shown in Figure 2 position 52.
Representative soReners have the following structure:
L (RCO) 2FDA] HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having From 12 to 22 capon atoms, and X is an anion or [ (RCONHCFI2CH~ QTR' ] AX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is a lower alkyl ' group, and X is an anion.
The preferred softer is Qua_soR~ 202-JR and 209-JR made by Quaker Chemical Corporation which is a mixture of linear amine amides arid imidazolines of the following structure:
(i) O H H Xe H O
al I I p Ci~H33-C-N-CHrCHs-IVY -CHI-CH2-N C-ClI~3 I
R' and Cd) . O H CHz-CIA
p I x~ / I
CItI~;-C-N-CHrCHz..IV~ N

R' C
I

wherein X is an anion.
As the nitrogenous cationic sofleaer/debonder reacts with a paper product during formation, the softener/debonder either ionically attaches to cellulose and reduces the number of sites available for hydrogen bonding thereby decreasing the extent of bber-to-fiber bonding or covaIently attaches to the crosslinking agent to produce improved softness due to enhanced substantivity of soRener to fiber.
The present im~ention may be used with a particular class of softener materials --amido amine salts derived from partially acid neutralized amines. Such materials are disclosed in U.S. Patent No. 4,720,383; column 3, lines 40-41. Also relevant are the following articles:
Evans, ~hemistr_v and~n,~usint. 5 July 1969, pp. 893-903; Egan, J. Am. Oil Chemist's Soc., Vol. 55 (1978), pp. 118-121; and Trivedi et aL, J. Am. Oil Chemist's Soc., June 1981, pp.
754-756. As indicated therein, softeners are often available commercially only as complex mixtures rather than as single compounds. While this discussion will focus on the predominant species, it should be understood that commercially available mixtures would generally be used to practice the invention.
At this time, Quasoft~ 202-1R and 209-JR is a prefen~ed softener material which is derived by alkylating a condensation product of oleic acid and diethylenetriamine. Synthesis conditions using a deficiency of alkylating agent (e.g., diethyl sulfate) and only one alkylating step, followed by pH adjustment to protonate the non-ethylated species, result in a mixture consisting of cationic ethylated and cationic non-ethylated species. A minor proportion (e.g., about 10 %) of the resulting amido amines cyclize to imidazoline compounds.
Since these materials are not quaternary ammonium compounds, they are pH-sensitive.
Therefore, in the practice of the present invention with this class of chemicals, the pH in the headbox should .be approximately 6 to 8, more preferably 6 to 7 and most preferably 6.5 to 7.
The softener employed for treatment of the furnish is provided at a treatment level that is suiEcient to impart a perceptible degree of softness to the paper product but less than an amount that would cause significant runnability and sheet strength problems in the final commercial product. The amount of softener employed, on a 100 % active basis, is preferably from about 0.1 pounds per ton of fiber in the furnish up to about 10 pounds per tan of fiber in the furnish, the more preferred amount is from about 2 to about 5 pounds per ton of fiber in the furnish.
Figures 3 through 5 demonstrate that dialdehydes are effective cnxslinking agents when combined with a base polymer such as polyvinyl alcohol and polyvinyl alcolwl-vinyl amine copolymer, and blend thereof.

Figures 4 and 5 illustrate that dialdehyde crosslinking increases adhesion in the presence of softener, as evidenced by higher adhesion values as measured by peel force and lower geometric mean tensile (GMT) parameters.
Esthetics and tactile considerations are extremely important for tissue products as they often come into intimate contact with the most delicate parts of the body in use. Consequently, demand is quite high for products with improved tactile qualities, particularly softness.
However, as tissue products are frequently used to avoid contact with that which the consumer would greatly prefer not to touch, softness alone is not su~cient; strength is also required Merely providing a product with improved properties is not generally sufficient, the "on the shelf' appearance of the product must suggest both strength and sof~ess while consumers must be able to sense improvements by handling packaged product. Appearance is critical;
bulk, weight, compressibility, firmness, texture and other qualities perceived as indicia of strength and softness are also required TAPPI 401 OM-88 (Revised 1988) provides a procedure for the identification of the types of fibers present in a sample of paper or paperboard and estimation of their quality.
Analysis of the amount of the softener/debonder chemicals retained on the tissue paper can be performed by any method accepted in the applicable art For the most sensitise cases, we prefer to x-ray photoelectron spectroscopy ESCA to measure nitrogen levels.
Normally, the background level is quite high and the variation between measurements quite high, so use of several replicates in a relatively modem ESCA system such as the Perkin Elzner Corporation's model 5600 is required to obtain more precise measurements. The level of cationic nitrogenous softener/debonder such as Quasoftt9 202-jR can alternatively be determined by solvent extraction of the Quasofttt9 202-JR by an organic solvent followed by liquid chromatography determination of the softenerldebonder.
Tensile strength of tissue produced in accordance with the presort inv~ti~ is measured in the machine direction and cross-machine direction ~ an InstronTM
tensile tester with the gauge length set to 4 inches. The area of tissue tested is assumed to be 3 inches wide by 4 inches long. A 20 pound load cell with heavyweight grips applied to the total width of the sample is employed The maximum load is recorded for each direction. The results are reported in units of "grams per 3-inch"; a more complete rendering of the units would be "grams per 3-inch by 4-inch strip".

17-MRY-1996 16 54 MATHYS & SQUIRE 0171 830 0001 P.21i62 Softness is a quality that does not lend itself to easy quantifica&on J.D.
Bates, in "SoRaess Inde~c Fact or Mu~age?°', TAPPL Vo148 (1965), No. 4, pp. 63A-64A, indica#es that tare two most important readily quantifiable properties for predicting perceived softness are (a) roughness and (b) what may be referred to as stiffness modules. Tissue and toweling produced according to the present invention have a more pleasing textiue as measured by reduced values of either or bolls roughness or s~ti~ess modules (relative to control samples).
Surface roughness can be evaluated by measuring geometric mean deviation in the coefficient of friction using a Kawabata KES~E Friction Tester equipped with a fingerprint type sensing unit using the low sensitivity range. A 25 g stylus weight is used, and the instrument readout is divided by 20 to obtain the mean deviation in the coe~cient of friction. The geometric mean . deviation in the coe~cient of friction (~) is then the square root of the product of the deviation in the machine direction and the cross-m-6wh'rae direction, thereafter is referred to as friction., The stiffness modules is determined by the procedure for measuring tensile streagth described above, except that a sample width of 1 inch is used and the modules recorded is the geometric mean of the ratio of 50 grams load over percent strain obtained from the load-strain curve.
The STFI values set forth in tables 1, 6, 7 and 8 are obtained by the method disclosed in the publication of the proceedings at the ?Yssue Making Corrfererrce, October 5-6, 1989 in Karlstad, Sweden entitled Characterization of Ct~e Structure by Image Analysis Magnus Folk, STFI, Sweden, pp. 39-50. In our method, the tissue is placed undor a stereo microscope with the Yankee side up and illuminated in the MD with oblique illumination roughly 10 degrees out of plane. Trnages (9) are collected at a magnification of 16X at 512x512x256 resolution and corrected for the nonuniforatiiy in illumination. The images are segmented (transformed from greylevel to binary) such that 50~/0 of the area is shadow.
Nme equally spaced scans are conducted on each image and the shadow lengths determined gad saved in a data base, The da9a are fitted interactively to an Erlang distribution to detennitte the best fit STET length is related to crepe coarseness - i.e. ~a lower SIFT number corresponds to a finer crepe stivc~ture which in turn contributes to higher perceived softness.

2 ~ 76898 17-MRY-1996 16:54 MRTHYS g SQUIRE 0171 830 0001 P.22i62 Example 1 lbis example ~uthe general papermalang Prods u~i~ag our adhesive ' formulations and opti~at softeners. Further data are set forth in Tables 1 and 2.
A fiunish of SO % Northern hardwood Iaaft and 50 % Northern softwood Matt was prepared The papermaloag machine v~ras ao inclined wire former with a Yankee dryer speed of 100 tt per minute. Two-tenths of a pound of base polymer with speci$ed crasslinldng agent . amount per ton of furnish was sprayed directly on the Yankee; the amount of softener sprayed on the Yankee side of the sheet is set forth in Table 1. The creping angle was maintained constant at n°. The bevel was 8°. The Yankee temperature was 101° C. The adhesive formulations were sprayed from position 51, as shown in Figure 2, directly on the Yankee, while the softeners, if used, were sprayed from position 52, as shown in Figure 2, which is the air side of the sheet on the Yankee.

2 ~ 16898 17-MRY-1996 16:54 MRTHYS 8~ SQUIRE 0171 830 0001 P.23i62 ~vWv~v ~i ~~~ ~ wC Co i 'ss~
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a 17-MRY-1996 16:54 MRTHYS & SQUIRE 0171 830 0001 P.24i62 EXBmple 2 Examples 2 and 3 dlusttate the maau~acturiag method for one and twu ply t. The adhesive and saRener data are not provided is these examples but are set forth in the subsequent examples.
A furnish of 50~/o Southern hardwood kraft sad 50'/o Soathera softwood kraft was prepared The papermaldng machine was as inclined wire former with a Yat3kee dryer speed of 1852 feet per minute. The operating data ~or the papermabng process are set forth is Table 2. A high basis weight base sheet was prepared Table 2 ONE PLY TISSUE SHEET VALUE
(HEAVY WEIGHl~

. Forming speed/reel speed 185Z/1519 $/min.

F~ 50 % SWK (NaheolaPine) 50 ~ I3WIC (Naheola .
Guts) Refining (softwood only) 25 hP

Stratiscation Homogeneous ...

MD/CD terisi7e ratio 2.0 - 2.5 Basis weight _ 16_6 lb./ream~

Dry stock flow 16 ' Ib./min Yankee sceam/Hood temp. - - I 00/700 (start pts.) psig/deg. F

Infrared heater ON

Moist~ae 4 Calendar load "Iow load"

l$

Crepe blade bevel 15 deg:
fee..... - ~nnn ~_ o ~_~~ ...y. ..

17-MRY-1996 16:55 MRTHYS & SQUIRE 0171 830 0001 P.25i62 Example 3 A furnish of 50 % Southern hardwood l~ aad 50 % Southern, softwood >aa~ v~
PreP~'ed. The pape=mabag taachine was as inclined wire former with a Yankee d=yer sped of 3450 feet per minute. ?he operating data for the papermalang process are set forth in Table 3. A lOw basis weight base sheet was prepared Table 3 TWO PLY TISSUE SHEET VALUE
(LIGHT WEIGATj ' Forming speed ~ 3450 ~~

Reel crepe 18 Yankee steam pressure 75 ' ' psi Wet end hood temperature550 d~ g Jet/wire ratio Headbox slice 0.500 m Refiner flow 48 Total headboac flow 1980 Refining (softwood only)42 hp Basis weight 9.6 lb./ream~

Moisture 4 Crepe blade bevel 15 deg.
tRPSIT11 ~ ~~n Cw ~sa1 17-MRY-1996 16:55 MATHYS 8, SQUIRE 0171 830 0001 P.26i62 Example 4 Table 4 provides the chemical code designation and description of the adhesives, crosslinkirig agents, softeners, and release agents employed in Examples l, 5, 6, 7 arid 8.
Table 4 Descriptions of Chemical omoaunds Used L~ Exam~l S-8 and Figures 3 - 5 csElvricAl, coMav~s DESIGNATION

H8290 (PAE) Houghton Rezosol~ 8290 adhesive (polyaminoamide-epichlorahydrin) AI ' Polyvinyl alcohol = 6 mol % vinyl amine copolymer GLYOXAL Crosslinldag agent for Al, supplied by Hoechst Celanese as 40 % solution AZC Ammonium zirconium carbonate (crosslinking agent for AI), supplied by esium Irlektron, Inc. as 20 % solution ACOTEA 20 202-JR Quaker Quasoft~ 202-JR softener (fariy diamide quest based on dieth lene triamine end C14-C18 unsaturated acids H565 Hou ton 565 release mineral 0~1 base AIRVOL -107 Polyvinyl Alcohol (Mot. Wt = 40,000 g/mol, Hydrolysis = 98 mot%), lied b Air Products and Chemicals, Inn AIRVOL - 540 Polyvinyl Alcohol (I~ioL Wt =155,000 g/mol, Hydrolysis = 88 mot%), s lied Air Products and Chemicals, Inc.

AIRVOL - 350 Polyvinyl Alcohol (Mot. Wt =155,000 g/mol, Hydrolysis = 98 mot/), su lied Air Products and Chemicals, Inc.

A1RVOL - 205 Polyvinyl Alcohol (MvL Wt ~ 40,000 g/mol, Hydrolysis = 88 mot%), su lied Air Products and Chemicals, Inc.

Example 5 This example gives the adhesive formulations far papermaldng process descxiibed in Examples 6, 7 and 8. In Tables 5, 6 and 7 data has beg set forth fnr each of the 17 cells.
Table 5 summarizes these examples and lists the cell number, base polymer, glyoxal, ammonium zirconium carbonate, softener, release agent and states whether' the furnish was refined or unrefined and gives the basis weight of the paper sheet The sheet tension values and sidedness parameters are not given in this table but are set forth in ?ables 6, 7 and 8 where applicable. ' 21 ?698 17-MRY-1996 16:55 MRTHYS & SQUIRE 0171 830 0001 P.27i62 _~
~ ' ' '~ ~ . . .~c~ ' ' b ~o ~ ~e~ ~o~ ,e ~o~o ~ d 6 ~O~0 ~G~D ~

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fVN N N N N N

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x~ s a a < T < a ~ , . . 5 r E

.

N t ~l H p h C ~ ~ ~ w r 1 0 ~ ._ a 1 C 0 r r H !
n Example 6 This example illustrates that when the adhesive consisting of PVOH-VAM
copolymer crosslinked with AZC is used, sheet tension values are obtained which are equivalent or better than the values obtained for the commercial PAE control producK. The base sheet for the two ply tissue was prepared according to the process of Example 3. The description of the additives, crosslinking agents, and softeners .are set forth in Table 5. Sheet tension and corresponding base sheet properties achieved wig the PVOH-VAM copolymer crosslinked with glyoxal or ammonium zirconium carboaate package are at least as good or better to the undesirable chlorine containing HoughtonTM 8290 (PAE) adhesive. The data is set forth in Table b. The ammonium zirconium carbonate package is superior to the PAE resin package and also to the glyoxal crosslinldng package as evidenced by lower STFI length and friction parameters.
It should be noted that glyoxal is added to the PVOH-VAM copolymer just prior to spraying on the Yankee dryer while the ammonium zirconium carbonate is sprayed separately but simultaneously with the PVOH-VAM copolymer.

'17-MRY-1996 16:55 MRTHYS & SQUIRE 0171 830 0001 P.29i62 Z

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s 1?-MRY-1996 16:56 MRTHYS 8~ SQUIRE 01?1 830 0001 P.30i62 Fxarnple 7 This example >7lustrates that using tfie novel a~tesive formulations with softeners facilitated the production of low sidedness one ply tissue. The base sheet for the one ply tissue was prepared according to the papemsakirtg Process ofExample 2.
The data for this Example are set forth in ?able ~ The data in Table 7 clearly demonsvate the a~esive capacity of aaunonium zirconium mate and glyoxal ctosslinldng agents. 1n this example softeners are nsed to reduce the sidedness of the one ply tissue. The data demonstrate that our novel adhes~ formulations are ' compatible with so$eners. , 17-MAY-1996 16:56 MRTHYS ~ SQUIRE 0171 830 0001 P.31i62 d n a A
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.
u~~ ~~ ~~~ ~~~ ~~~~~~g~
xRs<n=<~nx<~H~acH~<oSz ~~s ~~s ~~~~ t~~~ ~~~s ~~Cs ~°~.E '~a~, ::"~ss"~aHae"~sos"~:::".,::~ ' a N O N N O N N O O N tV ~~ D N N !i O N N V O H ~~~~'a~ ' O ~ p O ~ C O O ~ O O C ~ G C G ~% G O C ~ C
_.
V a~ ~ oo v .r, "' ~ ' ~ ~ ~ $

17-MRY-1996 16~56 MRTHYS 8 SQUIRE 0171 830 0001 P.32i62 Example 8 This example illustrates that using our novel adhesive formulations, high sheet tension is maintained, while giving the one ply tissue a low sidedness parameter relative to PAE control The base sheet for one ply was prepared according to the papermaidng process of Example 2.
The difference between Examples 7 sail 8 is that in this example the furnish was re$ned. The data in Table s demonstrate adhesive capacity of the base polymer whey coming in contact on the Yankee surface with the dialdehyde or zirconium crosslinbng agent is the presence of a softener resulting in lower sti$ness values relative to PAE control Using the refined furnish higher sheet tension values are obtained in the presence of a softener while still having a good sidedness parameter.

17-MRY-1996 16:56 MRTHYS 8 SQUIRE 0171 830 0001 P.33i62 t c d w ~, w N ~ v~
O O C
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~~s its ~:~: ~:~: ~~~: ~~~s ::,~:s".,: s sos,~sves,~ae:s",, ~. 's HaHHeHnse~H ~HnHoHHeoN.
O ~r O O .-. p p O ..i C C C C C G ~ O G O ~~ C
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Claims (57)

1. A creped fibrous web comprising a creping adhesive that comprises:
a) an adhesive composition comprising organic polymers having in the polymer backbone amine groups selected from the group consisting of primary amines, secondary amines and mixtures thereof and a crosslinking agent for crosslinking the polymer to the fibrous web at the drying surface said agent being a zirconium compound having a valence of plus four, b) in an amount sufficient to initiate cross linking.

2. The creped fibrous web of claim 1, wherein the organic polymer having primary and secondary amine groups is selected from the group consisting of chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine and polyaminoamide.

3. The creped fibrous web of claim 1 or 2, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

4. The creped fibrous web of claim 1 or 2, wherein the zirconium compound is ammonium zirconium carbonate.

5. The creped fibrous web of claim 1 or 2, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

6. The creped fibrous web of claim 1 or 2, wherein about 0.1 to about 10 pounds of cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

7. The creped fibrous web of claim 6, wherein the softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

8. The creped fibrous web of claim 6, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

9. The creped fibrous web of claim 6, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.

10. The creped fibrous web of chum 6, wherein the softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:
wherein X is an anion and R' is an alkyl group.

11. A creped fibrous web comprising a creping adhesive that comprises:
a) an adhesive composition comprising polyvinyl alcohol-vinyl amine copolymer of the following structure:

wherein m and n have values of 1 to 99 and 99 to 1 respectively, and a crosslinking agent for crosslinking the copolymer to the fibrous web at the Yankee dryer surface said agent being a zirconium compound having a valence of plus four, b) in an amount sufficient to initiate cross linking.

12. The creped fibrous web of claim 11, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

13. The creped fibrous web of claim 11, wherein the zirconium compound is ammonium zirconium carbonate.

14. The creped fibrous web of claim 11, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

15. The creped fibrous web of claim 11, wherein about 0.1 to about 10 pounds of a cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

16. The creped fibrous web of claim 15, wherein the softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

17. The creped fibrous web of claim 15, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX

wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

18. The creped fibrous web of claim 15, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.

19. The creped. fibrous web of claim 15, wherein the softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:
wherein X is an anion and R' is an alkyl group.

20. A creped towel comprising a creping adhesive that comprises:
a) an adhesive composition comprising organic polymers having in the polymer backbone amine groups selected from the group consisting of primary amines, secondary amines and mixtures thereof and a crosslinking agent for crosslinking the organic polymer to the fibrous web at the Yankee dryer surface said agent being a zirconium compound having a valence of plus four, b) in an amount sufficient to initiate cross linking.

21. The creped towel of claim 20, wherein the organic polymer is selected from the group consisting of chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine and polyaminoamide.

22. The creped towel of claim 20 or 21, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

23. The creped towel of claim 20 or 21, wherein the zirconium compound is ammonium zirconium carbonate.

24. The creped towel of claim 20 or 21, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

25. The creped towel of claim 20 or 21, wherein about 0.1 to about 10 pounds of a cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

26. The creped towel of claim 25, wherein the softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

27. The creped towel of claim 25, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

28. The creped towel of claim 25, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX

29 wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.
29. The creped towel of claim 25, wherein the softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:
wherein X is an anion and R' is an alkyl group.

30. A creped towel comprising a creping adhesive that comprises:
a) an adhesive composition comprising polyvinyl alcohol-vinyl amine copolymer of the following structure:
wherein m and n have values of 1 to 99 and 99 to 1 respectively, and a crosslinking agent for crosslinking the copolymer to the fibrous web at the Yankee dryer surface said agent being a zirconium compound having a valence of plus four, b) in an amount sufficient initiate cross linking.

31. The creped towel of claim 30, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

32. The creped towel of claim 30, wherein the zirconium compound is ammonium zirconium carbonate.

33. The creped towel of claim 30, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

34. The creped towel of claim 30, wherein about 0.1 to about 10 pounds of a cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

35. The creped towel of claim 34, wherein the softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

36. The creped towel of claim 34, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

37. The creped towel of claim 34, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.

38. The creped towel of claim 34, wherein the cationic softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:

wherein X is an anion and R' is an alkyl group.

39. A creped tissue comprising a creping adhesive that comprises:
a) an adhesive composition comprising organic polymers having in the polymer backbone amine groups selected from the group consisting of primary amines, secondary amines and mixtures thereof and a crosslinking agent for crosslinking the polymer to the fibrous web at the Yankee dryer surface said agent being a zirconium compound having a valence of plus four, b) in an amount sufficient to initiate cross linking.

40. The creped tissue of claim 39, wherein the organic polymer is selected from the group consisting of chitosan, polyvinylamine, polyvinyl alcohol-vinyl amine and polyaminoamide.

41. The creped tissue of claim 39 or 40, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

42. The creped tissue of claim 39 or claim 40, wherein the zirconium compound is ammonium zirconium carbonate.

43. The creped tissue of claim 39 or 40, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

44. The creped tissue of claim 39 or 40, wherein about 0.1 to about 10 pounds of a cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

45. The creped tissue of claim 44, wherein the cationic softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

46. The creped tissue of claim 44, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

47. The creped tissue of claim 44, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.

48. The creped tissue of claim 44, wherein the cationic softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:
wherein X is an anion and R' is an alkyl group.

49. ~A creped tissue comprising a creping adhesive that comprises:
(a) an adhesive composition comprising polyvinyl alcohol-vinyl amine copolymer of the following structure:
wherein m and n have values of 1 to 99 and 99 to 1 respectively, and a crosslinking agent for crosslinking the copolymer to the fibrous web at the drying surface said agent being a zirconium compound having a valence of plus four, (b) in an amount sufficient to initiate cross linking.

50. The creped tissue of claim 49, wherein the zirconium compound is selected from the group consisting of ammonium zirconium carbonate, zirconium acetylacetonate, zirconium acetate, zirconium carbonate, zirconium sulfate, zirconium phosphate, potassium zirconium carbonate, zirconium sodium phosphate and sodium zirconium tartrate.

51. The creped tissue of claim 49, wherein the zirconium compound is ammonium zirconium carbonate.

52. The creped tissue of claim 49, wherein about 0.1 to about 0.8 pounds of said adhesive composition are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

53. The creped tissue of claim 49, wherein about 0.1 to about 10 pounds of a cationic softener/debonder are added for each ton of cellulosic papermaking fibers in an aqueous furnish.

54. The creped tissue of claim 53, wherein the cationic softener/debonder is a nitrogenous compound selected from the group consisting of imidazolines, amido amine salts, linear amido amines, tetravalent ammonium salts, and mixtures thereof.

55. The creped tissue of claim 53, wherein the cationic softener/debonder has the following structure:
[(RCO)2EDA]HX
wherein EDA is a diethylenetriamine residue, R is the residue of a fatty acid having from 12 to 22 carbon atoms, and X is an anion.

56. The creped tissue of claim 53, wherein the cationic softener/debonder has the following structure:
[(RCONHCH2CH2)2NR']HX
wherein R is the residue of a fatty acid having from 12 to 22 carbon atoms, R' is an alkyl group, and X is an anion.

57. The creped tissue of claim 53, wherein the cationic softener/debonder is a mixture of linear amido amines and imidazolines of the following structure:
wherein X is an anion and R' is an alkyl group.