CA2165841A1 - Multi-layered tissue paper web comprising chemical softening compositions and binder materials and process for making the same - Google Patents

Abstract

Multi-layered tissue paper webs comprising chemical softener compositions and binder materials are disclosed. The multi-layered tissue webs are useful in the manufacture of soft, absorbent paper products such as facial tissues and/or toilet tissues. The multi-layered tissue paper products contain a chemical softening composition comprising a mixture of a quaternary ammonium compound and as polyhydroxy compound. Preferred quaternary ammonium compounds include dialkyl dimethyl ammonium salts such as di(hydrogenated)tallow dimethyl ammonium chloride, di(hydrogenated)tallow dimethyl ammonium methyl sulfate. Preferred polyhydroxy compounds are selected from the group consisting of glycerol, sorbitols, polyglycerols having a weight average molecular weight of from about 150 to about 800, polyxyethylene glycols and polyoxypropylene glycols having a weight average molecular weight from about 200 to 4000. The multi-layered tissue paper webs also contain an effective amount of binder materials to control linting and/or to offset the loss in tensile strength, if any, resulting from the use of the chemical softening compositions. The binder materials are selected from the various wet and dry strength additives, and retention aids used in the paper making art. Preferably, the majority of the chemical softening compositions will be disposed on the outer layers of the multi-layered tissue paper products where they are most effective. The binder materials are typically dispersed throughout the multi-layered product to control linting. In other words, the chemical softening compositions and the binder materials can be selectively distributed within the multi-layered tissue paper web to enhance the softness, absorbency, and/or lint resistance of a particular layer or ply.

Description

~ wo 95/01478 ~ ! 2 1 6 5 8 4 1 PCT/US94/06914 MULTI-LA~ERED TISSUE PAPER WEB COMPRISING CHEMICAL
SOFTENING CO~APOSITIONS AND BINDER MATERIALS AND
PROCESS FOR MAKING THE SAME
., FIELD OF THE INVENTION

This invention relates to multi-layered tissue paper web. More particularly, it relates to multi-layered tissue paper web comprising chemical softener compositions and binder materials. The treated tissue webs can be used to make soft, absorbent and lint resistance paper products such 8S facial tissue, and toilet tissue products.

BACKGROUND OF THE INVENTION

Paper webs or sheets, sometimes called tissue or paper tissue webs or sheets, find extensive use in modern society. Such items as ~acial and toilet tissues are staple items of commerce. It has long been recognized that tour important physical attributes of these products are thair strength, their softness, their absorbency, particularly their absorbency for ~ueous systems; and their Gnt resistance, particularly their lint resistance when wet. Research and development efforts have been directed to the improvement of each of these attributes without seriously affecting the others as well as to the improvement of two or three attributes simultaneously.
Strength is the ability of the product, and its constituent webs, to maintain physical inte~rity and to resist tearing, bursting, and shredding under use conditions, particularly when wet.
Softness is the tactile sensation perceived by the consumer as he/she holds a particular product, rubs it across his/her skin, or crumples it within his/her hand.
This tactile sensation is provided by a combination of several physical properties.
One of the most important physical properties related to softness is generally considered by those skilled in the art to be the stiffness of the paper web from " ' 'f wo 95/01478 t~. ~ PCT/US94/06914 which the product is made. Stiffness, in 1urn, is usually considered to be directly dependent on the dry tensile strength of the web and the stiflness ot the fiberswhich make up the web.
Absorbency is the measure of the ability of a product, and its constituent webs, to absorb quantities of liquid, particularly aqueous solutions or dispersions.
Overall absorbency as perceived by the consumer is generally considered to be a combination of the total quantity of liquid a given mass ot multi-layered tissuepaper will absorb at saturation as well as the rata at which the mass a~so~s theliquid.
Unt resistance is the ability of the fibrous pr~duct, and its constituent webs, to bind to~ether under usa conditions, particularly when wet. In other words, the hi~her the lint ~esislance is, the lower the ~ropensity of the web to Gnt will be.
The use of wet sl-en~th resins to enhanca the strength of a paper web is widely known. For example, Westfelt described a number of slJch .-.atenals and discussed their ch6lll;slry in Csl~u~Qse Chemistry and Techno'o~y, Volume 13, atpages 813-825 (1979). Freimark et al. in U.S. Pat. No. 3,755,220 issued August 28, 1973 mention that certain chemic~l additivas known as debon.l;n~ a~ents interfere with the natural hber-to-fiber bonding that occurs during sheet ~,...aL~n in paper making ~rucesses This reduction in bonding leads to a sotter, or bss harsh, sheet of paper. Freimark et al. 90 on to teach tha use of wet st~r~th resins in conjunction with the use of debonding sgents to off-set the undes..able effects of the debonding agents. These debonding agents do reduce both dry tensil~
strength and wet ~ensile slreh~JU-.
Shaw, in U.S. Pat. No. 3,821,068, issued Juna 28, 1974, also teaches that chemical debondera can be used to reduce the stil~ness, and thus enhance the so~lness, of a tissus paper web.
Chemical debonding agents have b9en disclosed in various refefences such as U.S. Pat. No. 3,554,862, issued to Hervey ~t al. on January 12, 1971.
- These materials includ~ quatsrnary ammonium salts such as cocotrimethylammonium chloride, oleyltrimethylammonium chlorids, di(hydrogenated)tallow dimethyl ammonium chloride and stearyltrimethyl ammonium chloride.
Emanuelsson et al., in U.S. Pat. No. 4,144,122, issued March 13, 1979, teach the use of complex quaternary a,-""or'um compounds such as bis(alkoxy(2-hydroxy)propylene) quaternary ammonium chlorides to soften webs. These authors also attempt to overcome any decrease in absorbency caused by the ~ wo 95~01478 - 2 1 6 5 8 4 1 PCT~Sg4/06914 debonders through ths us~ ot nonionic surfactants such as ethylene oxide and propylene oxide ~dducts of fatty alcohols.
Armak Company, of Chicago. Illinois, in their bulletin 76-17 (1977) disclose the use of dimethyl di(hydrogenated)tallow ammonium chloride in combination withfatty acid esters of polyoxyethylene glycols to impart both softness and absorbency to tissue paper webs.
Ona exemplary result of research directed toward improved paper webs is descnbed in U S. Pat. No. 3,301,746, issued to Sanford and Sisson on January 31, 1967. Despite the hTgh quality of paper webs made by the prvcess des~ii-,eci in this patent, and despite the co,-,l"6rc.;al success of products formad trom these webs, rdsearch effons d;.~c~ed to finding improved products have continued.
For exampl6, Becker et al. in U.S. Pat. No. ~,158,594, issued January 19, 1979, descfibe a m~thod they contend will form a strong, sofl, fibrous sheet. More specifically, they teach that the ~llen~tl. of a tissua paper web (which rnay have been softened by the addition of chemlcal debon iing a9ents) can be enhanceci byadheAng, during processing, one surface of the web to a cteping surface in a fine patterned arrangement by a bonding materAal (such as an acrylic latex rubber emulsion, a water soluble resin, or an elastomeAc bonding material) whkh has been adhered to one surfacs of the wab and to the creping surface in the fine patl6i"ed arran~ement, and creping the web from the creping surface to fonn a sheet materliai.
Conventional quat6n-z.ry a~ ,-on'Lm compounds such as the well known dialkyl dimethyl ammonium saits (e.g. ciitallow dimethyl ammonium chlorid~, ditallow dimethyl a-,----Gn ~m methyl sulfate, di(hydrogenated)tallow dimethyl ammonium chloride etc ...) are b(-~L~ chemical debonding agents. However, thsse quaternary ammonium compounds are hydrophobic, and can adversely aflect the abso,~enc~ of the traated paper webs.. Applicants have discovereci that mixing the qualer"ary ai"",Gn um compound with a polyhdroxy compound (e.g., glycerol, sorbitols, poly~lycerols or polyethylene glycols) wTII enhance both softness and absorbency rate of fibrous cellulose materials.
Unfortunately the use of chemical softenin~ co",positions co",prisin~ a quatemary ammonium compound and a poiyhydroxy compound can decrease the lint resistance of the treated paper webs. Applicants have discovered that the lint resistance can be improved throu~h the use of suitable bindar materials such as wet and dry stren~th resins and retention aid resins known in the paper making art.
The present invention Ts applicable to tissue paper in general, but particularily applicable to muiti-layered tissue tissue paper products such as those wo 95~01478 ~ . 2 1 6 5 8 4 1 PCT/US94/06914 ~

described in U.S. Patent 3,994,771, issued to Morgan Jr. et al. on Novemb~r 30, 1976, and incorporated herein by reference.
It is an object of this invention to provide soft, absorbent and lint resistancemulti-layered tissue paper products.
It is also a funher object of this invention to provide a process for making soft, absorbent, lint resistance multi-layered tissue paper products.
These and other objects are obtained using the present invention, as will become readily apparent from a reading of the followin~ scloslJ~e.

SUMMARY OF THE INVENTION

The present invention provides sofl, absorbent, llnt resistant multi-layered tissue paper products comprisin~ paper makin9 fibors, chsmical soRening compositions and binder materials. Briefly, the chemical so1I~ning coll~rositioncompfises a mixture ot:

(a) from about 0.01% to about 3.0% of a quaternary a",i"on um compound having the formula R ~ ~R1 /~\ X-wherein each R2 substituent is a Cl - C6 alkyl or hydroxyalkyl group, or mixturethereof; each R1 substituent is a C14 - C22 hydrocarbyl ~roup, or mixturs thereof; and X is a suitable anion; and (b) from about 0.01% to about 3.0% of a polyhydroxy compound; pre1erab~y selected from the group consisting of glycerol, sorbitols, polyglycerols havin~ a weight average molscular wei9ht ot from about 150 to about 800 and polyoxyethylene glycols and polyoxypropylene glycols having a weight average molecular weisht 1rom about 200 to 4000.

Preferably the weight ratio of the quaternary ammonium compound to the polyhydroxy compound ranges from about 1.0: 0.1 to 0.1: 1Ø It has been ~ WO 95/01478 2 1 6 5 ~ 4 1 PCTIUS94/06914 discovered that the chemical softenin~ composition is more effective when the polyhydroxy compound iand the quaternary ammonium compound are first pre-mixed together preferably at a temperature of at least 40 C, before being addedto the papermaking furnish.
Examples of quaternary ammonium compounds suit~'Q tor use in the present invention include the well-known dialkyldimethyla",-"Gn um salts such asDiTallow DiMethyl A"l",on um Chloride (DTDMAC), DiTallow DiMethyl Ammonium Methyl Sulfate (DTDMAMS), Di(Hydro9enated)Tallow DiMethyl Arnmonium Methyl Sulfate (DHTDMAMS), Di(Hydrogenated)Tallow DiMethyl A"",.on~m Chloride (DHTDMAC).
Examples of polyhydroxy compounds useful in the present invention include ~Iycerol, sGil~ilols, poly~lycerols having a wei9ht average -,o eaJl^~weight of from about 150 to about 800 and polyoxyethylene glycols having a weight average molecular weight of from about 200 to about 4000, with polyoxyeti,ylene ~Iycols having a weight avera~e molecular weight of from about 200 to about 600 being preferred.
The term binder refers to the various wet and dry at~en~Jth additives, and retention aids known in the art. These materials improve the lin~ es;s~ano~ of the tissue paper webs of the present invention as well as countetacting any decre 5ein tensile strength caused by chemical sof~ening compos;tions. Examples of suitebl~ binder matefials include permanent wet stren~th resins (i.a. Kymene ~
557H marketed by l~ercules Incorporated of Wilmington, DE), temporary wet strength rssins (i.e. ~alional starch 78-0080 marketed by ~Jational Starch and Chemical corporation of New-York, NY), dry slrefi~th resins (i.e. Acco ~ 51~"
Acco ~9 711 marketed by A",erican Cyanamid company of Wayne, New Jersey) and retention aid resins (i.e. Percol 0175 marketed by Allied Co"~ s oS Sulfolk,Virginia).
Brief!y, the pr~cess for making the multi-layered tissue paper webs of the present invenffon co",prises the steps of fo""ation of a multi-layered paper making furnish from the afore",enlioned components, deposition of the mul~-layered paper mahng fumish onto a foraminous surface such as a Fourdrinier wire, and removal of the water from the depos~led fumish.
All percentages, ratios and proportions herein are by weight unless otherwise specified.

2 1 658~4 1 WO 95/01478 ~ PCT/US94/06914 BRIEF DESCRIPTION OF THE DRAWINGS

While the Specification concludes with claims particularly pointing out and dislinctly claiming the present invention, it is believed the invention is better understood Irom the following descriplion taken in conjunction with the ~ssociated drawin~s, in which:
Figure 1 is a schematic cross-sectional view of a threa-layered single ply toilet tissue in accordance with the present invention.
Figure 2 is a schematic cross-sectional view of a two-layered t No-ply facial tissue in aa:ordance with the present invention.
The present invention is descfibed in more detail below.

DETAILED DESCRIPTION OF THE INVENTION

While this specific~;on concludes with claims particularly poinling out and distinctly claiming the subject mattar regarded as the invention, it is believad that the invention can be better under~lood from a reading of the following det~;~ed description and of the appended exampbs.
As used herein, the term lint resistance- is the ability of the fibrous product, and ns constituent webs, to bind together under use condilions, par~icularly when wet. In other words, ths higher the lint r~sistance is, the bwer the pn~pens ty of the web to lint will be.
As used herein, the term binder~ refers to the various wet and dry slf~r~l-resins and retention aid resins Icnown in the paper making art.
As used herein, the term water soluble~ refers to ,-a(erials that are soluble in water to at least 3% at 25 C.
As used herein, tho terms ~tissuo paper web, paper web, wsb, paper shoet and paper product~ all refer to sheats of paper made by a process comprising thasteps of forming an e~ueous paper making fumish, depositing this fumish on a foraminous surface, such as a Fourdrinier wire, and removing the water from the furnish as by ~ravity or vacuum-~ssisted cJr~tna~e, with or wnhout p,essing, andby evaporation.
As used herein, an ~queous paper rnakin~ furnish- Ts an aqueous slurry of paper making fibers and the chemicals described hereinafler.
As used herein, the term ~multi-layersd tissue paper web, muHi-layered paper web, multi-layered web, muHi-layered papar sheet and multi-layered paper product~ all refer to sheets of paper prepared from two or more layers of aqueous 2 t 6 5 8 4 1 WO 95/0l478 - - PCT/US94/06914 paper making furnish which are preferably comprised of different fiber types, ths fibers typically bein~ relatively long softwood and relatively short hardwood fibers as used in tissue paper makin~, The layers are preferably formed from the deposition of separate streams of dilute fiber slurries, upon one or more endless foraminous screens. If the individual layers are initially ~ormed on separate wires, the layers are subsequently combined (while wet) to form a layered co,l,posile web.
The first step in the pr~cess of this invention is the forming of an equeous paper making furnTsh. The furnish comprises paper making fibers (herein~ller some~imes referred to as wood pulp), and a mixture of at least one quaternary ammonium~compound, a polyhydroxy compound and binder i"dlerials all of which will be hereinaR~r deso,ibed.
It is antio;,Q~ted that wood pulp Tn all its varleties will normally oompnse thepaper making fibers used in this invention. 1 1oW6~ r~ other cellulose fibrous pulps, such as cotton liners, ba~sse, rayon, etc., can be used and none are discl~ecl.
Wood pulps useful herein include chemical pulps such as Kraft, sulfite and sulfate pulps as well as ",ecl,an-c -' pulps including for example, ground wood, the""o",echanical pulps and Chemi-ThermoM~ ~han;c-' Pulp (CTMP). Pulps derived from both de~duous and con;~erous trees can be used.
Both hardwood pulps and softwood pulps as well as blends ol the two rnay be employed. The terms hardwood pulps as used herein refers to fibrous pulp derived from the woody sul~lance of ~e~duous trees (angiosp6-,--s): her~-~softwood pulps ars fibrous pulps d~nved 1rom the woody subslance of coniferous trees (gy"~nospe""s). 1 laru~.~od pulps such 85 eucalyptus are parlicula~ily SUit:~ 16 for the outer layers of the mulli-layered tissue webs desc~ibsd her~ina~ler, whereas northem SOfh~; ~d Kraft pulps are preferrred for the inner layer(s) or ply(s). Also art'~ le to the pr~sent invention are fibers derived from recycled paper, which may contain any or all of the above categories as well as other non-fibrous materials such as fillers and adhesives used to f~ciliP~e the original paper makin~.
c~ l c~l Sottener cG~ oslllons The prssent invention conta;ns as an essential component a mixture of a quaternary ammonium compound and a polyhydroxy compound. The ratio of the quaternary ammonium compound to the polyhydroxy compound ranges from about 1.0: 0.1 to 0.1: 1.0; preferably, the wei~ht ratio of the quaternary ammonium compound to the polyhydroxy compound is about 1.0: 0.3 to 0.3: 1.0;
more preferably, the weight ratio of the quaternary ammonium compound to the wogs/01478 1 ' = ':. 21 6584 1 PCT/US94/06914 ~

polyhydroxy compound is about 1.0: 0.7 to 0.7: 1.0, although this ratio will vary depending upon the molecular weight o~ the par~icular polyhydroxy compound and/or quaternary ammonium compound used.
Each of these types of compounds will be described in detail below.
A. Quaternary Ammonlum Compound Ths chemical soflening composition contains as an essential component from about 0.01% to about 3.00% by weight, preferably from about 0.01% to about 1.00% by weight of a quaternary ammonium compound having the formula R~ ~R1 / \

In the s~ructure named above each R1 is C14-C22 hydr~,l,on group, pre~e~b~J
tallow, R2 is a C1 - C6 alkyl or hydroxyalkyl group, pref6r~1y C1~3 alkyl, X- is a su;te~le anion, such as an halide (e.9. chloride or bromide) or methyl sulfate. As discussed in Swem. Ed. in Bailey's Industrial Oil and Fat Products, Third E~ltion, John Wiley and Sons (New York 1964), tallow is a naturally ocaurrin~ ale~al having a variable cc ")position. Table 6.13 in the above-Wentifi6d referenc~ edited by Swsrn indica1es that typically 78% or more of the fatty acids of tallow contain 16 or t8 carbon atoms. Typically, half ot the fatty acids prosent in tallow are unsaturated, primarily in ths form of oleic acid. Synthetic as well as natural C' fall within the scs~pe of the present invention. Praferably, each Rl is C1 C18 alkyl, most preferably each R1 is strai~ht-chain C18 alkyl. Preferably, 3achR2 is methyl and X- is ch'cnde or methyl sulfate.
Examples of quaternary ammonium compounds suitabb for use in the prssent invention include the well-known dialkyldimethyl~Y~.nGn um salts such asditallow dimethyl an""on um chloride, ditallow dimethyla",i-,on um methyl sulfate, di(hydro~enated)tallow dimethyl smmonium chloride; with di(hydrogenated)tallow dimethyl ammonium methyl sulfate being preterred. This particular material is available commercially from Sherex Chemical Company Inc. of Dublin, Ohio under the tradename ~VarisoR ~!9 137~.
B. Polyhydroxy Compound .
.

~ wo 9S/01478 - 2 1 6 5 84 1 PCT/US94/06914 The chemical softening composition conlains as an essential component from about 0.01% to about 3.00% by wei~ht, preferably from about 0.01% to about 1.00% by weight of a polyhydroxy compound.
Examples of polyhydroxy compounds useful in the present invention include glycerol, sorbitols. polyglycerols havin9 a weight average molscul~r weight of from about 150 to about 800 and polyoxyethylen~ ~Iycols and polyoxypropylsne glycols having a weight avera~e molecular wei9ht of from about 200 to about 4000, preferably from about 200 to about 1000, most prelerably from about 200 to about600. Polyoxyethylene glycols havin9 an wei9ht average molQaJ~^~ weight ot from about 200 to about 600 are especi~lly pr~fer.ec. Mixtures ot the above~ies.~,ii,ed polyhydroxy compounds may also be used. For exa",l~le, mixtures of glycerol and polyoxyethylene glycols havin~ a wei9ht avera9e mo'a~l^~ weight from about 200 to 1000, more preferably from about 200 to 600 are useful in the present invention. Preferably, the wei~ht ratio ot glycerol to polyoxyethylene glyeol ranges from about 10 :1 to 1:10.
A panicularly preferred polyhydroxy eompound is polyoxyethylene glyeol having an weight average ".o'ecu'~ waight of about 400. This ,~terial is available eommarcially from the Union Carb~ds Coi"pany of Danbury, Conne~l~t under the tradena" ,e ~PEG-400-.
The chemical softening co"~ros~tion descfibed above l.e. mixture of a quaternary ammonium compounds and a polyl,~d~o,~y eompound are prefer~bly diluted to a desired conc6nl,alion to form a dispersion of the quat and poiyhydtoxy compounds before being added to the equeous slurry ot paper making fibers, or furnish, in the wet end of the paper makin9 machine at some suitable point aheadof the Fourdrinier wire or sheet forming stage. 1 lo~,~e~er, ~p~Ic^'ions of the above describQd chemical softening co--"~Gsition subselluent to lo",-ation of a wet Ussue web and prior to drying of the web to completion will also provide significant softness, absorbency, and wet slrergth benefits and are expressiy included within the scope of the present inven~ion.
It has been discovered that the che",ical soRening composition is more effective when the quaternary ammonium compound and the polyhydroxy compound are first pre-mixed to~etl)er before bein~ added to the paper making fumish. A p,efer,ed method, as will be described in ~reater detail hereinafter in Example 1, consisls of first heating ths polyhydroxy compound to a temperature of about 66 C (150F), and then adding the quaternary ammonium compound to the hot polyhydroxy compound to form a homogenous fluid. The weight ratio of the quaternary ammonium compound to the polyhydroxy compound ranges from WO 95/01478 . .-~ r ~ 2 1 6 5 8 4 1 PCT/US94/06914 ID

about 1.0: 0.1 to 0.1: 1.0; preferably, the wei~ht ratio of the quaternary ammonium compound to the polyhydroxy compound is about 1.0: 0.3 to 0.3: 1.0;
more preferably, the weight ratio of the quaternary ammonium compound to the polyhydroxy compound is about 1.0: 0.7 to 0.7: 1.0, although this ratio will va~depending upon the molecular weight ol the particular compound and/or quaternary ammonium compound used.
It has unexpectedly been found that the adsorption of the polyhydroxy compound onto paper is significantly enhancad when it is premixed with the quaternary ammonium compound and added to the paper by the above descnbed process. In fact, at least 20% of the polyhydroxy compound and the quater-,~ry ammonium compound added to the fibrous cellulose are ~lained; prelerably, the retention level of quaternary ammonium compound and the polyhydroxy compound is from about 50% to about 90% of the added levels.
Importantly, aclsGiption occurs at a conc3nt~ation and wXhin a time frame that are practical for use during paper rnaking. In an effort to better und6r~land the surprisingly hi~h retention rate o~ polyhydroxy compound onto the papsr, the physical science of the melted solution and the ~queous disp~rsion of a Di(Hydrogenated)Tallow DiMethyl Ammonium Methyl Sulfate (DHTDMAMS), and polyoxyethylene glycol 400 were studied.
Without wishing to be bound by theory, or to otherwise lim~t the present invention, the following d;scussion is offered for sxplaining how the qual~r.,ary ammonium compound promotes the adsG",tion of ths polyhydroxy compound onto paper.
In~or",alion on tha physical state of DHTDMAMS Di(Hydrogenated)Tallow DiMethyl Ammonium Methyl Sulfate. R2N+(CH3)2,CH30S03- and on DODMAMS
is provided by X-ray and NMR (Nuclsar Magnetic Resonance) data on ths commercial mixture. DODMAMS (DiOctadscyl DiMethyl Ammonium Methyl Sulfate, (C1gH37)2N ~ (CH3)2,CH3OSO3-) Ts a major c~,~,pon~n~ of DHTDMAMS, and sen~es as a model compound tor the commercial mixture. It is usetul to consider first the simpler DODMAMS system, and then the more complex commercial DHTDMAMS mixture.
Depending on the temperature, DODMAMS may ~xist in any of four phase states: two polymorphic crystals (X~ and X), a lamellar (Lam) liquid crystal, or a liquid phase. The X~ crystal exists from below room temperatur~ to 47 C. At this temperature it is transformed into the poly",ol~,h'~ xa crystal, which at 72 C is transformed into the Lam liquid crystal phase. This phase, in turn, is transformed into an isotropic liquid at 150 C. DHTDMAMS is expected to resemble ~ wo 95~01478 - 2 1 6 5 8 4 1 PCT/US94/06914 DODMAMS in its physical behavior. except that the temperatures of the phase transitions will be lowered and broadened. For example, the transition from the X~
to the X~ crystal occurs at 27 C in DHTDMAMS instead of 47 C as in DODMAMS. Also, calorimetric data indicat~ that several crystal ~ Lam phase transitions occur in DHTDMAMS rather than one as in DODMAMS. The onset temperature of the highest of thess transitions is 56 C, in ~ood agree",ent with the X-ray data.
DODMAC (D;~ct~decyl DiMethyl Ammonium Chloride) displays qu~ oly diflerent behavior from DODMAMS in that the Lam liquid crystal phase does not exist in this compound (Lau9hlin et al., Journal ot Physical Chemistry, PhyslcalSclence of the~ Dloctadecyldlmelhyla.--,--Gnlum Chlorlde-Water SYStQm. 1.
Equlllbrlum Phase r~ rlor, 1990, volums 94, pa~es 2546-2552, inco"~r~l6d herein by reference). This difference. ho~6v~r, is believed not to be irllpGitant to th~ use of this compound (or its cG"""er~al analog DHTDMAC) in the tfe~t~"6nl of paper.
Mixtures of DHTDMAMS with PEG~
A 1: 1 weight ratio mixture of thes~ two materials is studied. DODMAMS
and PEG are shown to be i".,--;scible at hi9h temperatures, where they coexist as two liquid phases. As mixtures of the two liquids within this region ars cooled, a Lam phase separates from the mixture. This study therefore shows that these two materials, whils immiscible at high temperatures do become misable at lower temperatures within the Lam liquid crystal phase. At still lower te,--peratures crystal phases are eYpected to separdte from the Lam phase, and the compounds are again i.n..l s~ bls These studies therefore suggest that in order to form good dispersions of DHTDMAMS and PEG-400 in water, the premix that is diluted with water should be held within the inter")ed;ate teinperature range where the two compounds are bl~
Mlxtures of DHTDMAC wlth PEG 400.
Phase studies of these two materials using the step-wise dilution method demonstrate that their physical behavior is considerably different from that of DHTDMAMS. No liquid crystal phases are found. Thsse compounds are miscible as liquid soiution over a wide ran~e of temperatures, which indicates that dispersions may be prepared from these mixtures over a comparabls ranga of temperatures. In particular no upper temperature limit of miscibility exists.
atlon of dlsperslons.

WO 95/01478 ~ 2 1 6 5 8 4 1 PCT/US94/06914 Dispersions of either of these materials may be prepared by dilutin~ a premix, that is held at a temperature at which the polyhydroxy compound and the quaternary ammonium salt are miscible, with water. It does not matter greatly whether they are miscible as a liquid crystalline phase (as in the casa of DHTDMAMS), or as a liquid phasa (as in the case of DHTDMAC). Neither DHTDMAMS nor DHTDMAC are soluble in water, so that dilution of either dry phase with water will precipitate the quaternary ammonium compound as small particles. Both quaternary ammonium compounds will pi~c;pit~le at elevated temperatures as a liquid-c~stal phase in dilute aqueous solutions, regardles~ ofwhether the dry solution was liquid or liquid crystalline. The polyhydroxy compound is soluble with water in all prupo,~ions, so is not prec;p~
Cryoelectron microscopy demonstrates that the particles present in the dispersion aro about 0.1 to 1.0 micro",eters in siza, and hi9hly varied in stn)cture.
Some are shests (curved or flat), while others are closed vesicles. The membranes of all thsse particles are bilayers of i ~13 C 11~r di.-,ens;ons in which the head ~roups are exposed to water, the tails ar~ to~ether. The PEG is presumed tobe associ~ed with these particles. Tha ~p'ic^~ion of dispa,aions p~pared in thTsmanner to paper results in atIach-"e,n of the quaternary alru--Gniu~n ion to thepaper, strongly p,o,.-otes the aJsGI~tion of ths polyhydroxy compound onto paper, and produces the desired enhancel"~nt of sonness with retention of wettabi~ty.
State of the allsp~rslons.
When the above described d;sp6r~ions ars cooled, the partial crystallization of the ",alerial within the colloidal partides may occur. I lo~lovar, it is akely that the attainment of the equilibfium state ~11 require a long time (perhaps months), sothat the membranes within thoss particles that interact with paper are in a disordered state.
It is believed that the vesicles containing DHTDMAMS and PEG break apart upon dryin~ of the fibrous cellulosic material. Once the ~/esicle is broken, themajority of the PEG component may penetrate into the interior of the cellulose fibers where it enhances the fiber flexibility. Importantly, some of tha PEG is retained on the surface of the fiber where it acts to enhance the absGrl,ency rate of the cellulose fibers. Due to ionic inte.~ ions, the majority of the DHTDMAMS
component stays on the surface of the cel~u'ose fiber, whsre it enhances the surface ~eel and soaness ot the paper product.
Blnder materlals The present invention contains as an essential coi"ponent from about 0.01%
to about 3.0%, preferably from about 0.01% to about 1% by weight of a binder ~ wo 95~01478 2 1 6 5 ~ 4 1 PCT/US94/06914 material selected from the group consistin~ of permanent wet strength resins, temporary wet strength resins, dry strength resins, retention aid resins and mixtures thereof. The binder materials act to control linting and also to offset the loss in tensile strensth, if any, resulting from the chemical softener compositions.
If permanent wet strength is desired, the binder materials can be chosen from the following group of chemicals: polyamide-epichlorohydrin, polyacryl~,r. ~es, styrene-butadiene iatexes; insolubilized polyvinyl alcohol; urea-formaldehyda; polyethylensimine; chitosan polymers and mixtures Shereot.
Polyamide-epichlorohydrin resins are cationic wet strangth resins whtdl have been found to be of particular utility. Su;'^~'a types of such resins are Jascol,ed in U.S. Patent No. 3,700,623, issuad on October 24,1972, and 3,772,076, issued on November 13, 1973, both issued to Keim and both bein9 hereby ;nco"~o,~ted by reference. One commercial source of a useful polyamide-opichlorohydrfn resins isHercules, Inc. of Wilmington, Delaware, which markets such restn under the mark Kymeme ~ 557H.
Polyacrylamide resins have also been found to be of utility as wat sl,~r~th resins or retantion aids. These resins are dascnbed in U.S. Patant No. 3,~6,93?.issued on January 19, 1971, to Coscia, et al. and 3,556,933, issued on January 19, 1971, to Williams et al., both patents bein9 illc6lpGidt~d herein by reference.
One commerdal source of polyacryl~nide resins is Amefican Cyanamid Co. of Stanford, Connecti~n, which markets one such resin under the mark Parez ~ 631 NC. Oth~r commercial sources of caliGnir polyacrylamTde resins are Allied Colloids of Sulfolk. Virginia, and Hercules, Inc. of ~llmington, Delaware, whichmarkets such resins under the marks Percol 0 175 and Reten 0 1 23æ
SUII other water-soluble calior,-~ resins finding utilit~r In this invention aro urea formaldehyde and melamine formaldehyde resins. Ths more COn.,nGn hnctional groups of these polyfunctional resins ue nit.o9en containin~ groups such as amino groups and methylol groups attached to nitro~en. Polyethylenimine ~pe resins may also find utility in the present invention.
If temporary wet strength is desired, the binder matefials can be chosen from the following group of starch-based temporary wet :>ltefi9UI resins: cationic dialdehyde starch-based resin (such as Caldas produced by Japan Carl~t or Cobond 1000 produced by National Starch); dialdehyde starch; and~or the resin described in U.S. Patent No. 4,981,557 issued on January 1, 1991, to Bjorkquist and inco.~,o.al~d herein by reference.
If dry strength is desired, the binder materials can be chosen from the following group of materials: polyacrylamide (such as combinations of Cypro 514 } , . 21 65841 _ s WO 9~;/01478 ~ PCT/US94/06914 and Accostrength 711 produced by American cyanamid of Wayne, N.J.); starch (such as corn starch or potato starch); polyvinyl alcohol (such as Airvol 540 produced by Air Products Inc of Allentown, PA); guar or locust bean ~ums;
polyacrylate latexes; and/or carboxymethyl cellulose (such as Aqualon CMC-T
from Aqualon Co., Wllmington, DE). In general, suitable starch tor practiGn~ thepresent Invention is characterized by water solubility, and hydrophilieity.
Exemplary starch materials include eorn starch and potato stareh, albeit it is not intended to thereby limit the seope of suiteb!e starch materials; and waxy eom starch that is known industrially as amioea starch is partieularly pre~6"~ nioeastarch differs from common corn stareh in that it is entirely amylopectin, wheroas common corn starch contains both amphpectin and amylose. Various unique characteristics of amioca stareh are turther descfibed in Amioea - The Stareh trom Waxy Corn~, H. H. Schopmeyer, food Industries, Deee.nber 1945, pp. 106-108 (Vol. pp. 1476-1478). The stareh ean be in granubr or dispersed fom albeit granular form is preferreld. The stareh is preferably suffieiently eooksd to induee swelling of the granules. More pfelerably, the starch granules are swollen, as by eooking, to a point just prior to dispersion of the stareh granule. Sueh highiy swollen starch granules shall be ,~fe,~d to as being hlly cool~e_l . Tha eonditions for dispersion in general can vary depending upon the size of the starch granules, ths degree of crystallinity of the granules, and the amount of amylose present.
Fully cooked amioca stareh, for exampla, ean be pr~pa ed by heating an ~usous slurry of about 4X eonsisler~ of stareh granules at about 190 F (about 88 C) for between about 30 and about 40 minutes. Olher exemplary stareh matsrials whhh may be used include ",o ~;lied cationie starchas such as those modified to haYe nitrogen con~ning groups sueh as amino groups and ~ tl-ylol groups ~ttached to nitro~en, available from National Stareh and Chemical Company, (Bridga~ iter, New Jersey). Such ",~;.~d starch matafials are used primafily as a pulp fumish additive to increase wet and/or dry sll~n-~lll. Considem)g that such modified starch materials are more expensive than u"",o llfied sl~r~;hss, the latter hava gcnerally been preferred.
Methods of epplic~tion inelude, the same previously described with reference to ap,c' c~1ion of other chemical add;ti~cs pr~f~rably by wet end addition, spraying; and, less preferably, by printing. The binder may bs applied to the tissua paper web alone, simultaneously with, prior to, or slJbsequent to the addition of softener, absorbency, and/or aesthetic additives. At least an effective amount of a binder, preferably starch, to provide lint eontrol and conco,n;tant strength increase upon dryin~ relativa to a non-binder traated but otherwise identical sheet is WO 95/01478 ~ 2 1 6 5 ~ 4 1 PCT/US94/06914 pre~erably applied to the sheet. Preferably, between about 0.01% and about 3.0%
of a binder; is retained in the dried sheet, calculated on a dry fiber wei~ht basis;
and~ more preferably, between about 0.1% and about 1.0% of a binder material, preferably starch-based, is retained.

The second step in the process of this invention is the depositing of the multi-layered paper making furnish using the abova described chemical softener composition and binder materials as additives on a foraminous surface and th~
third step is the removing of the water trom the fumish so ~Jeposite~) Techni~uss and equipment which can be used to accomplish these two processTng steps will be readily apparent to those sk~lled in the paper mahn9 art. Preferred multi-layer~d tissue paper embodiments ot the present invention contain from about 0.01% to about 3.0%, more preferably from about 0.1% to 1.0% by weight, on a dry fiber basis of the chemical softening composition and binder matsrials described herein.
The present invention is arplic~'a to multi-layered tissue paper in general, including but not limited to conventionally felt-press~d multi-layered tissue paper;
hi~h bulk pattem densified multi-layered tissue paper, and high bulk"JncGr"p~ct~multi-layered tissue paper. The multi-layered tissue paper products made therefrom may be of a singls-ply or multi-ply construction. Tissue structures formed from layered paper webs are d~scfib~d in U.S. Patent 3,994,771, Morgan, Jr. et al. issued November 30, 1976, and inco",ora~6d herein by referenoe. In general, a wet-laid co",posite, soft, bulky and absorbent paper structure is prepared from two or more layers of fumish which are preferdbly col,-prised of different fiber types. The layers are preferably formed from the deposition of separate streams of diluts fiber slurries, the fibers typically being relatively long softwood and relatively short hardwood fib~rs as used in multi-layered tissue paper making, upon one or more endlsss foraminous screens. If the individual layers are initially formed on separate wires, the layers are subsequently combined (while wet) to form a layered composite web. The layered web is subse~luently caused toconform to the surface of an open m~sh dfying/i-"pri"ting fabric by the a~,c'lc-~ion of a fluid force to the web and thereafter thermally predried on said fabric as part of a low density paper making process. The layered web may be s1ra1i~ied with respect to fiber type or the fiber content of ths respective layers may be essentially the same. The multi-layered tissue paper preferably has a basis weight of between 10 s/m2 and about 65 ~/m2, and density of about 0.60 g/cm3 or less. Preferably, basis weight will be below about 35 g/m2 or less; and density will be about 0.30 WO 95tO1478 i -~ ~U `~ i . t ~ ' 2 1 6 5 8 4 1 PCT/US94/06914 g/cm3 or less. Most preferably density will be between 0.04 g/cm3 and 0.20 g/cm3.
The multi-layered tissue paper webs of the present invention comprise at Ieast two superposed layers a first layer and at least one second layer cont~uous with the first layer. Preferably the multi-layered tissue papers comprise three superpossd layers an inner or centsr layer, and two outer layers with the inner layer located between the two outer layers. The two outer layers preferably comprise a primary filamen~ary constituent of about 60% or more by weight ot relatively short paper making fibers having an average fiber between about 0.2 and about 1.5 mm. These short papsr mahin9 fibers are typicaliy hal~ ood fibers,preferabiy eucalyptus fibers. Altematively, low cost sources of short fibers such as sulfite fibers the""o",ecl,anical pulp, Chemi-ThermoMechanical Pulp (CTMP) fibers, recycled fibers, including fibers fractionated from ecycled fibers and mixtures theraof can be used in one or both of the outer layers or blendsd in the inner layer, if desired. The inner layer preferably comprises a primary filamentary constituent of about 60% or more by weight of relativeq long paper mahng fibers having an average fiber length of Isast about 2.0 mm. These long paper making fibers are typically Soll-Yood fibers, preferably, northern sottwood Kraft fibars.
Figure 1 is a sche",atic cross-sectional view of a three-layered single ply toilet tissue in accordance with the present invention. Referring to Figure 1, the three layered single ply web 10, oo",prises three supe",osed byers, inner layer 12, and two outer iayers 11. Outer layers 11 are cGi--pnsed pr.,-)zJ;ly of short paper making fibers 16; whereas inner layer 121s comprised primariiy of bng paper making fibers 17.
In an alternate pr~fe"sd e--,boJi"-ent of the present invenUon, mu~ti-ply tissue paper products are forrned by placing at laast two multi-layered tissue paper webs in j~n~ rosed relation. For example, a two-ply tissue paper product can be made co",prisin3 a first two-layered tissue paper web and a second h~o-layered tissue paper web in jv~tarosed relation. In this example, each ply is a two-layer tissue sheet comprising a first layer and a second layer. The first layer preferably comprises the short hardwood fibers and the second layer preferably comprises the long sollwood fibers. The two plys are combined in a "anner such that the short hardwood flbers of each ply face outwardly, and the layers containing the lon~ softwood fibers face inwardly. Figure 2 is a schematic cross-sectional view of a two-layered two-ply facial tissue in accordance with the present invention. Referring to figure 2, the two-layered two- ply web 20, is comprised of two plies 15 in juxt~rosed relation. Each ply 15 is comprised of inner layer 19,- and outer layer 18. Outer layers 18 are comprised primarily of short paper ---~ Wo 95/01478 ,; ~ ~ 2 1 6 5 8 4 1 PCTIUS94/06914 making fibers 16; whereas inner iayers 19 are comprised primarily of long papermaking fibers 17. Similarly three-ply tissue paper products can be made by piacing three multi-layered tissue paper webs in juxtaposed relation.
It should not be inferred from the above discussion that the present invention is limited to tissue papsr products comprising thrsa-layers -- sin~le ply or two-plys -- two layers, etc. Tissue paper products consisting of three or mora plys in combination with each ply consisting of one or more layers ars also expressly meant to be included within the scope of the present i-,.ontion.
Prefer~bly, the majority of t~c quaternary a"""on1um compound and the polyhydroxy compound is contained in at least one ot the outer byers of the mutti-layered tissue paper web of the presenl invention. More prele,dbly, the ll~joftyof the quaternary ammonium compound and the polyl.~d.vxy compound is contained in both of th~ outer layers. It has been discovered that the chemical softening co- "position is most effective when added to the outer byers or plies of the tissue paper products. There, the mixture of the quaternary compound and polyhdroxy compound act to snhance both the soflness and the absorbancy of the multi-layered tissue products of the present invention. Referring to figures 1 and 2, the chemical softenin9 cG.,~position comprisin9 a mixture of the ~ t~.-.ary ammonium compound and the polyhdroxy compound is schematically reprdsent6d by dark circles 14. It can be seen in fi9ures 1 and 2 that the "-ajo~;ty of the chemical softenin9 compo~ition 14 is contained in outer layers 11 and 18, respectively.
However, it has also been discovered that the lint resistance of the multilayereq tissue paper products dec,~ases with the Inclusion of the quale---sry ammonium oompound and the polyhd--,xy compound. Therefor~" binder -,~enals are used for linting control and to incfease the tensile slrength. Preferably, the binder is contained in the inner layer and at least one of the outer layers of the multi-layered tissue paper webs of the present invention. More preferably, the binder is contained throughout the multi-layered product, i.e., in the inner andouter layers. Referrin~ to figures 1 and 2, the binder materials are schen,atically represented by white circles 13. It can be seen in figures 1 and 2 that the "ajo~ty of the binder materials 13 are contained in inner layers 12 and 19 respecti~ely. In an alternate preferred embodiment (not shown), the majority of the binder is contained in at least one of the outer layers, more preferdbly both of the two outer layers of the multi-layered product.
The combination of the chemical softening composition comprising a quaternary ammonium compound and a polyhdroxy compound in conjunction with ' `'~7'~ ' 21 65841 WO 95/01478 - ~ PCT/US94/06914 a binder material results in a tissue paper product having superior softness, absorbency, and lint resistanc~ properties. Selectively addin~ ths majority of the chemical softening composition to the outer layers or plys of the tissue paper, enhances its effectiveness. Typically the binder materials are dispersed throughout the tissue shset to control linting. 1 lo~,e\,0r, liks the chemical softening composition, the binder materials can bs selsctively added where most needed.
Conventionally pressed multi-layered tissue paper and methods for making such paper are known in the art. Such paper is typically made by depo~ ng paper making turnish on a foraminous forming wire. This forming wira is oftsn ~1611~ to in the art as a Fourdrinier wire. Once the furnish is deposit~d on the forrning wire, it is referred to as a web. The web is dewatered by transf~r-ing to a d~.~at~ning felt, pressing the web and drying at elevated temperature. The particular techniquss and typical equipment for makin~ wsbs accGrdin~ to the process just d~scnbed arswell known to thoss skilled in ths art. In a typical process, a bw consistency pulp furnish is provided in a pressurized he~dbox The heeJlG~ has an open'ng for delivering a thin deposit of pulp furnish onto the Fourdrinier wire to form a wet web.
Ths web is then typically dewatered to a fiber consistency of betwean about 7%
and about 25% (total wsb weight basis) by vacuum dewatering and further dewatered by pressing opsrations wherein the web Ts subjected to prsssure developed by oppos;ng mechanical rnem~ers, for example, cylindr;cal rolls.
The ds-~ater~d web is then furlher ~ressed during transfar and being dried by a stream drum apparatus known in U~e art as a Yankee dlyer. Prsssure can be daveloped at the Yankee dryer by mechanical means such 8S an opposing cylindrical drum pressing against the web. Vacuum may also be applisd to the web as it is presssd a~ainst ths Yankee surface. Multipla Yankee dryer drums maybs smployed, whereby additional pr~ssing is optionally incurred between the dnums. The multi-layered tissue paper stn~ctures which are 10rmed are f~fe,-ed to hsreinafter as conventional. pressed, multi-layered Ussue paper structures. Suchshssts are considered to b~ co",pac~ed since the web is subject~d to subs~an~lalmechanical compression forcss whils the fibers are moist and are then drisd while in a co",prdssed state.
Pattern densifisd multi-layered tissue paper is charact~fiLed by havin~ a relatively high bulk field of relativsly low fiber dsnsity and an array of dsnsified zonss of relatively high fiber dsnsity. The hi~h bulk fi61d is alternatively characterized as a field of pillow regions. The densified zones are alternatively referred to as knuckle regions. The densified zones may be discretely spaced within ths high bulk field or may be intarconnected, either fully or partially, within WO 95/01478 ` ~s ~ 2 1 6 584 t PCT/US94/06914 the high bulk field. Preferred processes for making pattern densified tissue webs ars disclosed in U.S. Patent No. 3,301,746, issued to Sanford and Sisson on January 31,1967, U.S. Patent No. 3,974,025, issued to Peter G. Ayers on August 10,1976, and U.S. Patent No. 4,191,609, issued to Paul D. Trokhan on March 4, 1980, and U.S. Patent 4,637,859, issued to Paul D. Trokhan on January 20,1987;
all of which are inco",Grated hsrein by rsference.
In gsneral, pattsrn densifisd webs are preferably prepared by dep,os~tir,g a paper making furnish on a foraminous forming wira such as a Fourdrinier wire to form a wet web and then j~tarosing the web against an array of supports. ~he wsb is i~ressad against ths array of supports, thereby resultin~ in dsnsified zones in the web at the locations ~eog,dph ~ y corraspondin~ to the points of contact between the array of supports and the wet web. The remaindsr of the web not compressed during this operation is rsferred to as the high bulk field. This high bulk field can be further dsdensi~isd by app'-c-tion of fluid prsssure, such as with a vacuum type dsvice or a blow-through drysr. The web is de~ Qred, and optional~y prsdried, in such a mannsr so as to substantially avoid comprsssion of the hi~h bulk field. This is preferably accomplished by fluid pressure, such as with a vacuum type device or blow-through dryer, or all~r--al~ly by ,-,~chan ~lly pr~ss;~g the web against an array of supports wherein the high bulk fiel~d is not co",pressed. The operations of dewaterin9, optional predrying and f~r"~tion of the densified zones may be int~grat~d or partially integrated to reduce the total number of ~r~ssing steps performed. Subsecluent to formaLon of the dens;fi~
zones, dewate~ing, and optional pr~drying, the web is dried to OG~I ~le~ on, preferably still avoiding ",echar-c~' prcssing. Preferably, from about 8h to about 55% of the mulb-layered tissue paper surface cc~i"prises clens r~ d knudcles having a rslativs density of at least 125% o1 the density of the high bulk fiald.
The array of suppons is preferably an imprinting carrier fabric having a panerned ~ispl~c~",ent of knuckles which operate as the array of suppofts which fadlitate the for~nalion of ths dsnsifisd zones upon apFl cqtion of pr~ssure. The pansrn of knucklss constitutes the array of supports previously refsrred to.
Imprinting carrier fabrics are J;sclosed in U.S. Patent No. 3,301,746, Sanford and Sisson, issued January 31,1967, U.S. Patsnt No. 3,821,068, Salvuffl, Jr. et al ., issued May 21, 1974, U.S. Patent No. 3,974,025, Ayers, issued Au~ust 10,1976, U.S. Patent No. 3,573.164. Friedbsrg et al ., issued March 30,1971, U.S. Patent No. 3,473,576, Amneus, issued October 21, 1969, U.S. Patsnt No. 4,239,065, Trokhan, issusd December 16, 1980, and U.S. Patent No. 4,528,239, Trokhan, issued July 9,1985, all of which are incorporated herein by f~erencs.

WO 95/01478 i ~ 2 1 6 5 8 4 1 PCT/US94/06914 Preferably, the furnish is first formed into a wet web on a foraminous ~orming carrier, such as a Fourdrinier wire. The web is dewatered and transferred to an imprinting fabric. The furnish may alternately be initially deposited on aforaminous supporting carrier which also operates as an imprinting fabric. Once formed, the wet web is dewatered and, prsferably, thermaliy predlied to a sslected fibsr consistency of between about 40% and about 80%. Dewatering can be performed with suction boxes or other vacuum devices or with blow-through dryers. The knuckle imprint of tha imprinting fabric is impressed in the web as discussed above, prior to dryin9 the web to completion. One method for accomplishing this is throu~h ap~' c-tion of mschanical pressure. This can be dons, for exampls, by pressing a nip toll which supports the imprinting fabric against the face of a drying dnum, such as a Yankee dryer, wherein the web is disposed between the nip roll and drying dnum. Also, prefer~bly, the web is molded against the imprinting fabric prior to completion of dr~in9 by applicaUon of fluid pressure with a vacuum device such as a suction box, or with a blow-through dryer. Fluid prsssure may bs applied to induce impression of densified zones during initial dewatering, in a separate, subsequent process stage, or a combination ther~of.
UncG,-,pacled, nonpattern-densified multi-layared tissue paper stnJctures are described in U.S. Patent No. 3,812,000 issued to Joseph L Sah~ucci, 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 on June 17, 1980, both of which are incG"~Gra~ed herein by reference. In gen6rdl, u, co-"pacted, non pattern densi~ed multi-layered tissue paper structures are prepared by depos;ting a paper making fumish on a foraminous formin~ wire such as a Fourdrinier wire toform a wet web, draining the web and removing additional water without mechanical co",pression until the web has a fiber consistency of at least 80%, and creping the web. Water is rsmoved from the web by vacuum dewatering and thermal drying. The resultin~ structura is a soft but weak hi~h bulk sheet of relatively unco",pacted fibers. Bonding mat9riai is preferably applied to portions of the web prior to crepin~.
The multi-layered tissue paper web of this invention can be used in any application where soft, absorbent multi-layered tissue paper webs are required.
Particularly advantageous uses of the multi-layered tissue paper web of this - invention are in toilet tissue and fadal tissue products. For example, two multi-Iayered tissue paper webs of this invention can be ply-bonded to form 2-ply facial or toilet tissue products.

~ wo 95~01478 2 1 6 5 8 4 1 PCT/US94/06914 Molecular Weight Delermlnatlon A. Introductlon The essential distin~uishing characteristic of polyme~ric materials is their molecular size. The properties which have enabled polymers to be used in a diversity of ~ppl c~tions derivs almost entirely from their macro-mclscul~r nature.
In order to characterize fully these materials it is essential to have some means of detining and de~termining their molecular wei~hts and molecular wsight distributions. It is more correct to USB the term relative molacu~ mass rathsr the molecul~r weight, but the latter is used mors generally in pol~rmer techn~ . It is not always practical to dstermine ~ e~ul~ wei~ht distributions. I lo~aver, this is becoming mors common practics using chromatographic techniques. Rather, recourse is made to expressing molec.ul~ size in terms of molec~l~r weight averages.
B. ~olecul~r wel~ht avera~es It we consider a simple ".olecul~ weight distribution which .eprssenls the weight fraction (wj) of molecules havin~ relativs molecular mass (Mj), it is possible to define several useful average valuss. Averaging carried out on ths basis of the number of molecules (Nj) of a particular size (Mj) gives th~ Number Average Molecular Weight ~in 3 S Ni M
Ni An important conseq.~ence of this dsfinition is that the Number Avsrags Molecular Weight in grarns contains Avogadro's Number of molQcu'~ s This de~finition of moleclJI~ weight is consistent with that ot .,onodisper~e molecular species, i.a. ,r ~'s~Lles having the same molecular weight. Ot more si~nificance is the reco~nition that it the numbe~r ot molecules in a given mass of a polydisperse polym~r can be determined in some way then l~n, can be ~I~te~
readily. This is ths basis ot colligative property measurements.
Averaging on ths basis ot t~he weight fractions (Wj) of mo'ecu'es ot a giv~n mass (Mj) leads to the definition of Weight Avera~e Molecu~a~ Wei~hls ~w = S.Wi Ni ~ ~ NiMj2 Wj ~: Nj Mj wo 95~01478 - - 2 1 6 5 8 4 1 PCT/US94/06914 ~

Mw is a mor~ useful means for expressing polymer molecular wei~hts lhan Mn since it reflects more accurately such properties as melt viscosity and mechanical properties of polymers and is therefor used in the present invention.

Analytical and Testing ProcedureQ

Analysis of the amount of treatment ch3micals used herein or retained on multi-layered tissue paper webs can be par~ormed by any --etl,Gd ~pt~d in ths applicable art.
A. Quan~ltall~r~ analysls for quat~rnary ammonlum and polyh~d~GI~y compounds For example, the level of the qual~r.,ary ammonium compound, such as Di(Hydro~enated)Tallow DiMethyl Ammonium Methyl Sulfate (DHTDMAMS) retained by the multi-layered tissue paper can be determined by solvent e~.tion of the DHTDMAMS by an or~anic solvent f~"~weci by an an-on!c~oation--~ titrationusin~ Dimidium Bromide as indicator; the level of the polyhydroxy compound, suchas PEG-400, can be determined by ~xtraction in an ~qvsous solvent such as water followed by gas chro(),a~G~,aphf or colonmetry ted~niques to determine thelevel of PEG-400 in the extract. These ~ lhoJs ara ex6,--pl&ry, and are not meant to exc~ude other methods which may be usehl for determining levels of par~cular c ",ponents retained by the multi hyored Ussue paper.
B. Hydrophlllclty (absG.Le.~c~) Hydrophilicity of multi-layered tissue paper refers, in general, ~o tha propensity of the multi-layered Ussue we~ to be wetted with water. ~Iyd~uphir~ity of multi-layered tissue paper may b~ somewhat quantified by dele-",;ning the pefiod of time required for dry multi-layered tissue paper to becGn-a compl~telywetted with water. This pefiod of tim~ is referred to as ~wetting time-. In or~er to provide a consistent and repe~t~'a test for wetting time, the follo~in~ procedure may be used for wettin~ time detQI"~inations hrst, a cor~litioned sample unit shset (the environmental conditions fortesting of paper sa",plas are 23+1C and 50~2%
R.H. as specifiod in TAPPI Method T 402), approximately 4-3/8 inch x 4-314 Inch (about 11.1 cm x 12 cm) of muiti-layered tissue paper structure is provid~d;
second, the sheet is folded into four (4) j~Ytarosed quarters, and then crumpbd into a ball approximately 0.75 inches (about 1.9 cm) to about 1 inch (about 2.5 cm) in diameter; third, the balled sheet is placed on the surface of a body of distilled water at 23 ~ 1C and a timer is simultan~ously staned; fourth, the timer is 2 1 6 5 ~4 1 WO 95/01478 ~ PCT/US94/06914 stopped and read when wetting of the balled sheet is completed. Complet~ wettin~is observed visually.
Hydrophilicity characters of multi-layered tissue paper embodiments of the present invantion may, of course, be determined immediately after manufacture.
However, substantial increases in hydrophobicity may occur during the first two weeks after ths multi-layered tissue paper is made: i.e., after the paper has a~ed two t2) weeks following its manufacture. Thus, the wetting times are prelerably measured at the end ot such two week period. Accordingly, wetting times measured at the end of a t~,vo week agin9 period at room temperature are referred to as ~two week wetting times.r C. Denslty The density of multi-layered tissue paper, as that term is used herein, is the avera~e density ~'cul~ted as the basis weight of that paper divided by the caliper, with the appropridte unit conversions incorporated therein. Caliper of the multi-layered tissue paper, as used herein, is the thickness of the paper when subjected to a compressive load of 95 g/jn2 (15.5 g/cm2).
D. Llnt Dry llnt Dry lint can be measurHd using a Sutl,erland Rub Tester, a piece of black felt, a four pound weight and a Hunter Color meter. The Sutherland tester is a motor-driven instrument which can stroke a w6ight6cl sample back and forth across a stalionary sa,-,pl~ The piece of black telt is atlached to the four pound weight. The tester then rubs or moves ths w~ighted felt over a s~a~Gnary issue sample for five strokes. The Hunter Color L value of the blacl~ felt is determined be~ore and alter rubbing. The difference in the two Hunter Color readings constitutes a measurement of dry linting. Other methods known in the prior arts for measuring dry lint also can be used.
Wet llnt A sui~ble proceJure ~or measurin~ the wet linting propc.l~ of tissue samples is desc,ibe~.l in U.S. Patent No. 4,950,545; issued to Walter et al., onAugust 21, 1990, and incor~.Grdl6cl herein by reference. Tha procedure essentialiy involves passin~ a tissue sample through two steel rolls, one of which is panially submerged in a water bath. Lint from tha tissue sample is transfer,~d to the steel roll which is moistened by the water bath. The continued rotalio-l of the stael roll deposits the lint into the water bath. The lint is recovered and then counted. See col. 5, line 45 - col. 6, line 27 of the Walter et al. patent. Other methods known in the prior an for measuring wet lint also can bs used.

wo 95~01478 ; = v . ~ ~ ~ 2 1 6 5 8 4 1 PCTlUS94/06914 ~1 Optional Ingredlents .

Other chemicals commonly used in paper makin~ can be added to the chemical softening composition described herein, or to the paper making furnish so lon~ as they do not significantly and adversely affect the softenin~, absGrl~ncy of the fibrous material, and enhancing actions of the chemical so~tening col"posi~ion.
For example, surfactants may be used to treat the multi-layerad tissue paper webs of the present invention. The level of su-la .1anl, if used, is pr~fe.~ly from about 0.01% to about 2.0% by wei9ht, bassd on the dry fiber wei~ht of the multi-layered tissue paper. The surfactants pr~ferdbl)r have alkyl chains with sight or mora carbon atoms. Exemplary anionic su-Iaclants are rlnear alkyi sulfonates,and alkyl~enzene sulfonates. Exemplary non-on-~ surfactants are alkyiglycoside~
includin~ alkyl~lycoside esters such as Crodesla SL-40 which is available from Croda, Inc. (New York, NY); alkylglycoside ethers as described in U.S. Patent 4.01 1,389, issued to W. K. Lan9don, et al. on March 8, 1977; and alkylpolyethoxylated esters such as regosperss 200 I~L availabls from Glyco Chemicals, Inc. (Greenwich. CT) and IGEPAL RC-520 available from Rhone Poulenc Co"~oration (Cranbury, N.J.).
The above r~stings of optional chemical ad~iti~res is ir~Iencled to be mers~
examplary in nature, and are not meant to limit the scope of the invenUon.
The following exa",pl6s Tllustrate the prd~,lice of the present invenUon but are not intended to be limiting thereof.

F~1rLE 1 The purposs of this example is to illustrate a ",elhcd that can be used to make-up a chemical softener composition comprising a mixture of Di(Hydrogenated)Tallow DiMathyl Ammonium Methyl Sulfate (DHTDMAMS) and Polyoxyethylena Glycol 400 (PEG-400).
A chemical softener composition is prepared according to the following procedure: 1. An equivalent wei~ht of DHTDMAMS and PEG-400 is v.~i~hed separately; 2. PEG is heated up to about 66 C (150 F); 3. DHTDMAMS is dissolved in tha PEG to form a melted solution at 66 C (150 F); 4. Adequ~ta mixing is provided to form a homogenous mixture of DHTDMAMS in PEG; 5.

WO g5/01478 ; . `''t~ 2 1 6 5 ~ 4 1 PCTIUS94/06914 The homogenous mixture of (4) is cooled down to a solid form at room temperature.
The chemical softaner composition of (5) can be pre-mixed (steps 1-5 above) at the chemical supplier (e.~. Sherex company of Dublin Ohio) and then economically shipped to the ultimate users of the chemical softening complosition where it can then be diluted to the desired concentration.

The purposs of this sxample is to illustrate a l~le~hGd that can be used to make-up a chemical soflen9r composition which comprises a rnixture ot Di(Hydrogenated)Tallow DiM thyl Ammonium Methyl Sulfate (DHTDMAMS) and a mixture of Glycerol and PEG-400.
A chemical soflener composition is preparad according to the following procedure: 1. A mixture of Glycerol and PEG-400 is blended at 75: 25 by weight ratio; 2. Equivalent weightS of DHTDMAMS and the mixture of (1) are v.ei~htad separately; 3. The mixture of (1) is heated up to about 66 C (150 F); 4.
DHTDMAMS is dissolved in (3) to form a melt9d solution at 66 C (t50 F); 5.
~de~u~te mixing is provided to form a homo9enous mixture of DHTDMAMS in (3); 6. The ho",ogenous mixture of (5) is coolsd down to a solid form at room te",p6rahlre.
The chemical softener co-,-posilion of (6) can be pre-mixed (steps 1-6 above) at the chemical suppli~r (e.9. Sherex co,,lpanJ of Dublin Ohio) and then economica!ly shippcd to the ultimate users of the chemical so~len;ng c~-"pos;lion where it can then be diluted to the desir~d concantl~tion.

The purpose of this example is to illustrate a method using blow through dryinQ and layered paper makin~ techniques to make soft absorbent and lint resistance toilet multi-layered tissue paper treated with a chemical soflener composition comprising Di(Hydrogenated)Tallow DiMethyl Ammonium Methyl Sulfate (DHTDMAMS) and a Polyoxyethylene Glycol 400 (PEG-400) and a temporary wet sl,~r~th resin.
A pilot scale Fourdrinier paper making machine is used in the practic6 of thc present invention. First, the chemical softener composiUon is prepared accordingto the procedure in Example 1 whsrein the homogenous premix of DHTDMAMS

and polyhydroxy compounds in solid state is re-melted at a temperature of about 66 C t1 50F). The melted mixture is then dispersed in a conditioned water tank(Temperature - 66 C) to form a sub-micron vesicl~ dispersion. The panicle size of the vesicle dispersion is dstermined using an opticai microscopic technique. Thaparticle size range is trom about 0.1 to 1.0 micron.
Second, a 3% by wei~ht aqueous slurry of NSK is made up in a conventional re-pulper. The NSK slurry is refined gently and a 2% solution of the temporary wet slrergth resin (i.e. National starch 78-0080 marketed by ~JalionalStarch and Chemical co,l,ordtion of New-York, NY) is addsd to the NSK stock pipeat a rate of 0.75% by weight of tha dry fibers. The adsG-~on of the te---por~ty wet strength resin onto NSK fibers is enhanced by an in-line mixer. The NSK slurry is diluted to about 0.2% consist~ncy at the fan pump.
Third, a 3% by weight ~ueous slurry of Eucalyptus fibers is made up in a conventional re-pulper. A 2% solution of the temporary wet strength resin (i.e.
National starch 78-0080 marketed by National Starch and Chemical co,~r~tion of New-York, NY) is added to tha Eucalyptus stock pipe before the stock pump at a rate of 0.1% by weight of tha dry fibers; and a 1YO solution of the chemical softener mixture is added to ths Eucalyptus stock pipe before the in-line mixer at a rats of 0.2% by weight of the dry fibsrs. The Eucalyptus slurry is dil~ed to about 0.2%
consistency at the fan pump.
The treated fumish mixture (30% of NSK / 70YO of Eucalyptus) is blsnded in the head box and deposited onto a Fourdrinier wirs to ~orrn an e--lbryor. ~ web.Dewaterin9 occurs through the Fou~ ir,:sr wire and is a~s;st~d by a d~ or and vacuum boxes. The Fourdrinier wire is of a ~shed, satin weave confi~uration having 84 machine-direction and 76 cross-,--achine~Jir~on monofilaments per inch, resps~,ti~ . Ths smbryonic wet wab is ~fahsl6rled from the photo-poly...erwire, at a fiber consislency of about 15% at tha point of transfer, to a photo-polymer fabric havin~ 562 Linear Idaho cells per square in~ch, 40 percent knuckle area and 9 mils of photo-polymer depth. Further de-watefing is acco".plished by vacuum assisted drainage until the web has a fiber consistency of about 28%.
The patterned web is prs-dried by air blow-through to a fiber consistency of about 65% by weight. The web is then adhered to the surface of a Yankee dryer with a sprayed creping adhesivs coi"prisin~ 0.25% aqueovs solution of Polyvinyl Alcohol(PVA). The fiber consistency is increased to an esli---aled 96% before the dry creping the web with a doctor blade. The doctor blade has a bevel angls of about25 degrees and is positioned with rsspect to the Yankee dryer to provide an impact angls of about 81 degrees; the Yankea drysr is operated at about 800 fpm ~ wo 95/01478 - f~ ~ r ~ 2 l 6 5 8 4 1 PCTIUS94/06914 (f~et per minuta) (about 244 meters per minute). The dry web is formed into roll at a speed of 700 fpm (214 meters per minutes).
The web is convened into a one ply multi-layered tissus paper product. The multi-layered tissu~ pap~r has about 18 #/3M Sq Ft basis weight, contains about 0.2% of the chamical softener mixture and about 0.3% of the temporary wet stren~th resin. Importantly, the resultin9 multi-layered tissue papsr is sOn, absorbsnt, has ~ood lint resistance and is slJit~hlQ for use as facial and/or toilet tissues.

EXAM~LE ~, The purpose of this example is to illustrate a method using a blow through dryin~ paper making technique to make soft, absorbent and lint resistance toiletmulti-layered tissue paper treated with a chemical sof~ener co,-,position ccs,-,prlsin~
Di(Hydro~enated)Tallow DiMethyl Ammonium Chloride (DHTDMAC) and a mixture of polyhydroxy compound (Glycerol / PEG-400) and a dry strength additive resin.
A pilot scala Fourdrinier paper making machine is used in the ç,r~ctice of the present invention. First, the chemical softener c;",pGsition is prepared aocording to the procedure in Example 2 wherein ths homogenous premix of DHTDMAC and polyh~droxy compounds in solid sta~e is re-melted at a temperature of about 66 C (150 F). The melted mixtur~ is then clispe-sed in a conditioned water tank (Temperature - 66 C) to form a sub-micron vesicle dispersion. The particle si~e of the vesicle dispersion i8 d~ter---;ned using u optical microscop c technique. The particle size ran~e is from about 0.1 to 1.0 micron.
Second, a 3h by weight ~queous slurry of NSK is made up in a convenlional re-pulper. The NSK slurry is refined gantly and a 2h solution ot the dry sl~englh resin (i.e. Acco ~ 514, Acco ~ 711 ",ark~ted by American Cyanarnid company of Fairfield, OH) is added to the NSK stock pipc at a rate of 0.2% by wei~ht of the dry fibers. The adsorption of the dry strength resin onto NSK fibers is enhanced by an in-lin~ mixer. The NSK slurry is diluted to about 0.2% consislency at the fan p~mp.
Third, a 3% by wsi~ht aqueous slurry of Eucalyptus fibers is made up in a conventional re-pulper. A 2% solution of the dry stren~th resin (i.e. Acco ~9514, Acco ~!9 711 marketed by American Cyanamid company of FairfieW, OH) is added to the Eucalyptus stock pipe be~ore the stock pump at a rate of 0.1% by weight of the dry fibers; and a 1% solution of the chemical soflener mixture is added to the WO 95/01478 ` - ~ 2 1 6 5 8 4 1 PCT/US94/06914 Eucalyptus stock pipe before the in-line mixer at a rate of 0.2% by wei~ht of the dry fibers. The Eucalyptus slurry is diluted to about 0.2% consistency at the fan pump The treated furnish mixture ~30% of NSK / 70% of Eucalyptus) is blended in the head box and deposited onto a Fourdrinier wira to fomn an embryonic web.
Dewatenng occurs through the Fourdrinier wire and is ~cs;~led by a deflector andvacuum boxes. The Fourdrinier wire is of a 5-shed, satin wsave configuration having 84 machins-direction and 76 cross-machine-direction monohlaments per inch, respectiveiy. The embryonic wet web is transferrQd trom the photo-polymer wire, at a fiber consis~ency of about 15% at tho point of bdns~r, to a photo-polymer fabric having 562 Unear Idaho cells per square inch, 40 percent knuckle area and 9 mils of photo-polymer depth. Further de-watering is accomplished by vacuum assisted drainage until the web has a fiber consislency of about 28%.
The patterned web is pre-dried by air blow-through to a fiber c~n..lstency of about 65% by weight. The web is then adhered to the surface of a Yankee dryer with a sprayed creping adhasive comprising 0.26% aqueous solution of Polyvinyl Alcohol (PVA). The fiber consistency is increased to an esli,--aled 96% before the dry creping the web with a doctor blade. The doctor blade has a bevel an~le of about25 degrees and is positioned with respe~l to the Yankee dryer to provWe an impact angle of about 81 de~es; the Yankee dryer is ope,cdsd at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is fonned into roll at a speed of 700 fpm ( 21~ meters per minutes).
Two plies of the web are formed into multi-layered Uswe paper products and laminating them to~etl-er using ply bonded techniqus. The multi-layered tissus paper has about 23 #/3M Sq R basis weight, contains about 0.1% of the chemical softener mixture and about 0.2% of the dry slrenStl, resin. Importantly, the resulting multi-layered tissue paper is soft, absorbent, has good lint resistance and is suitetlQ for use as fadal and/or toilet tissues The purpose of this axample is to illustrate a method using a conventional drying paper making technique to make soft, absorbent and rlnt resistance toiletmulti-layered tissue paper treated with a chemical softener ce"-posilion comprising Di(Hydrogenated)Tallow DiMethyl Ammonium Methyl Sulfate (DHTDMAMS) and a Polyoxyethylene Glycol 400 (PEG-400), a dry strength additive and a cationic polyacrylamide additive resin (Percol ~ 175) as retention aid.

~ WO 95/01478 ' ~ t- 2 1 6 5 8 4 1 PCT/US94/06914 A pilot scale Fourdrinier paper making machine is used in tha practice of the present invention. First th~ chemical softener composition is prepared acconJingto the procedure in Example 1 wherein the homogenous premix of DHTDMAMS
and PEG-400 in solid state is dispersed in a conditioned water tank (Temperature- 66 C) to form a sub-micron vesicle dispersion. The particb size of the vesicle dispersion is deler",ined usin9 an optical micr scop c technique. The particle size range is from about 0.1 to 1.0 micron.
Second, a 3% by wei9ht aqueous slurry of NSK is made up in a conventional re-pulper. Th~ NSK slurry is refined gently and a 2% solution of the dry strength resin (i.e. Acco 514, Acco 711 n,a,keted by A~erican Cyanamid company of Wayne, New Jersey) is added to the NSK stock pipe at a rate of 0.2~o by weight of the dry fibers. The adsorption of the dry slr~h~ll. resin onto NSK
fibers is enhanced by an in-line mixer. The NSK slurry is diluted to about 0.2%
consislen y at the fan pump.
Third, a 3% by weight a~lJeous slurry of Eucalyptus fibers is made up in a conventional re-pulper. A 1% solution of the chemical soSIensr mixture is added to the Eucalyptus stock pipe before the stock pump at a rata of 0.2Yo by weight of the dry fib~rs; and a 0.05% solution of Percol ~ 1 7S is added to the Eucalyptus layers before the fan pump at a rate of 0.05% by weight of the dry filDers. The adsG-~iGn of the chemical soflener mixture to Eucalyptus fibers can be enhanc~d by an in-line mixer. The Eucalyptus slurry is dTluted to about 0.2Yo cDns stency at the fan pump.
The treated fumish mixture (30% of NSK / 70% of Euca~ptus) is blended in the head box and depos;led onto a Fourdrinier wire to form an e"~bryon-~ web.
Dawa~erin9 occurs through the Fo~,J~in-3r wire and is ~ 1~ by a d~tle.~r and vacuum boxes. The Fourdrinier wire is of a ~shed, satin weave conf~uration having 84 machine-direction and 76 cross-machine~li~clion -,on~f - ~ents per inch, respectively. The embryonic wet web is transferred from the Fo~.fdrin,sr wire, at a fiber cons;-~len~ of about 15% at ths point of l-ar,s~er, to a conventional feK. Further de-watering is accol, r'-shed by vacuum ~ssisted draina~e until theweb has a fiber consislency of about 35%. The web is thsn adhered to the surface of a Yankee dryer. The fber consistency is Increased to an esli---aled 96% before the dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 d6grees and is posilioned with respect to the Yankee dryer to provide an impact angle of about 81 de~rees; the Yankee dryer is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is forrned into roll at a speed of 700 fpm (214 meters per minutes).

WO 95/01478 . _ t _ 2 1 6 5 8 4 1 PCT/US94106914 Two plies of the web are formed into multi-layered tissue paper products and laminating them together using ply bonded technique. Ths multi-layered tissue paper has about 23 #/3M Sq. Ft. basis wei~ht, contains about 0.1% of the chemical softener mixture, about 0.1% of the dry strength resin and about 0.05%
of the retention aid resin. Importantly, the resuiting muiti-layered tissue paper is soft, absorbent, has sood lint resistance and is suitable for US9 as a facial and/or toilet tissues.

The purpose of this e%ample is to illustrate a method using a blow through drying and layered paper makin~ techniques to make sott, sbsGri-uent and lint resistance facial multi-layerad tissue paper treated with a chemical softener composition comprising Di(Hydrogenated)Tallow DiMethyl A,.~ on1Lm Msthyl Sulfate (DHTDMAMS) and a poiyoxyeu~flene Glycol 400 (PEG-400), a permanent wet stren~th resin and a retention aid (Percol ~ 175 ).
A pilot scale Fourdrinier paper making machine is useci in the ~ . tic~ of the present invention. Flrst, the chemicai softenar cGI~lpGsiffon is pr~par~ accotding to the procedure in Example 1 wherein the ho",Ggenous premix ot DHTDMAMS
and polyhydroxy compounds in solid state is re-meited at a te~ 6idhr~ of abou~
66 C (1 50F). The melted mixture is then dispersed in a conditioned water tank(Temperaturs ~ 66 C) to form a sui~micron vesicie d;spe- ~on. The par~c-ie sizs of the vesicle dispersion is determined using an optkai mia~sxp-~ techni~ue. The particle size range is from about 0.1 to 1.0 micron.
Second, a 3% by weight ~ueous slurry ot NSK is mada up in a conventional re-pulper. The NSK slurry is refined gentiy and a 2% solution of the permanent wet strength rasin (i.e. Kymene~t~ 557H marketed by Hercules Incorporated of Wilmington, DE) is aWed to the NSK stock pipe at 8 rate of 1% bywei~ht of tha dry fibers. The adsoi~tion of the te,nporary wet s~len~h resin onto NSK fibers is enhanced by an in-line mixer. The NSK slurry is dilutsd to about 0.2% consistency at the fan pump.
Third, a 3% by weight equeous slurry of Eucalyptus fibers is made up in a conventional re-pulper. . A 1% solution of the chemical soflener mixture is added to the Eucalyptus stock pipe before the in-line mixer at a rate ot 0.2% by weight of the dry fibers; and a 0.5% solution of Percol Z9 175 is added to the Eucalyptus layers before the fan pump at a rate of 0.05% by wei~ht of the d~y fibers. The Eucalyptus slurry is diluted Io about 0.2% consistency at the fan pump.

wo 95~01478 ~ ~- ~ 2 1 6 5 8 4 1 PCT/US94/06914 Th~ treated furnish mixture (50% of NSK / 50% of Eucalyptus) is blended in the head box and deposited onto a Fourdrinier wire to form an embryonic web.
Dewatering occurs through the Fourdrinier wire and is assisted by a deflector and vacuum boxes. The Fourdrinier wir~ is ot a 5-shed, satin weav~ configuration having 84 machine-direction and 76 cross-machine-direction ."onofilaments per inch, respectively. The embryonic wet web is transferred from the photo-polymer wire, at a fiber consis(ency of about 15% at the point of t,ans1er, to a photo-poiymer fabric having 711 Linear Idaho cells per square inch, 40 percent knuckiearea and 9 mils of photo-polymer depth. Furlher de vJalering is accomplished by vacuum ~ssisted cllaina~e until the web has a fiber consistencr of about 28Yo.
The p~tterned web is pre-dfied by air blow-throu~h to a fiber con~slenc y of about 65% by wei~ht. The web is then a~Jh6red to the surlace of a Yankee dryer with a sprayed creping adhesive comprising 0.25% ~queous solution of r~in~l Alcohol (PVA). The fiber consistency is incroased to an eslin-ated 96% befors the dry creping the web with a doctor blade. The doctor blade has a bevel angle of about25 de~rees and is positioned with respect to the Yankee dryer to provide an impact an~ls of about 81 degrees; tho Yankee dryer is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is brmeci into roll at a speed of 700 tpm (214 meters per minutes).
The web is con~c. le i into a two piy muiti-layered facial tissue paper. The mu~ti-layered tissue paper hss about 21 #/3M Sq Ft basis weight, contains about 1% ot the permanent wet strength resin, sbout 0.2% of the chemicsl softener mixture and about 0.05~6 of the retontion aid resin. I...po~tant~, the resuttingmulti-layered tissue paper is soft, absorbent, has good iint resi~lance and is suit- ~la for use as fadai tissues

Claims (10)

What is Claimed is:

1. A multi-layered tissue paper web characterized in that it comprises at least two superposed layers, a first layer and at least one second layer contiguous said first layer, said multi-layered web comprising:
a) paper making fibers;
b) from 0.01% to 3.0% of a quaternary ammonium compound having the formula X-wherein each R2 substituent is a C1 - C6 alkyl or hydroxyalkyl group, or mixture thereof, preferably C1 - C3 alkyl, most preferably methyl; each R1 substituent is a C14 - C22 hydrocarbyl group, or mixture thereof, preferably C16 - C18 alkyl; and X- is a suitable anion, preferably chloride or methyl sulfate;
c) from 0.1% to 3.0% of a water soluble polyhydroxy compound;
wherein said polyhydroxy compound is preferably selected from glycerol, sorbitols, polyglycerols having a weight average molecular weight of from 150 to 800, polyoxyethylene glycols and polyoxypropylene glycols having a weight average molecular weight from 200 to 4000, preferably from 200 to 1000, most preferably from 200 to 600, and mixtures thereof;
and d) from 0.01% to 3.0% of a binder material wherein said binder material is preferably selected from permanent wet strength resins, preferably polyamide-epichlorohydrin, or polyacrylamide permanent wet strength resins, and mixtures thereof, temporary wet strength resins, preferably a starch-based temporary wet strength resin, dry strength resins, retention aid resins and mixtures thereof.

2. The multi-layered tissue paper web of Claim 1 wherein said multi-layered web comprises three superposed layers, an inner layer and two outer layers, said inner layer being located between two said outer layers, said multi-layered web preferably comprising a single ply, wherein said quaternary ammonium compound, said water soluble polyhdroxy compound, and said binder material are each contained in one or more of said layers of said multi-layered web.

3. The multi-layered tissue paper web of Claim 2 wherein the majority of the quaternary ammonium compound and the polyhydroxy compound is contained in at least one of said outer layers, preferably in both of said outer layers.

4. The multi-layered tissue paper web of Claim 2 or 3 wherein the majority of the binder is contained in said inner layer.

5. The multi-layered tissue paper web of any or Claims 2 - 4 wherein said inner layer comprises relatively long paper making fibers, preferably softwood fibers, most preferably northern softwood fibers, said long paper making fibers having an average length of at least 2.0 mm and wherein each of two said outer layers comprises relatively short paper making fibers, preferably hardwood fibers, most preferably eucalyptus fibers, said short paper making fibers having an average length between 0.2 and 1.5 mm.

6. The multi-layered tissue paper web of Claim 5 wherein said inner layer comprises mixtures of softwood fibers and low cost fibers, and at least one of said outer layers comprises low cost fibers or mixtures of hardwood fibers and low cost fibers, wherein said low cost fibers are selected from sulfite fibers, thermomechanical pulp fibers, chemi-thermomechanical pulp fibers, recycled fibers, and mixtures thereof.

7. The multi-layered tissue paper web of any of Claims 1 - 6 wherein the quaternary ammonium compound is di(hydrogenated)tallow dimethyl ammonium chloride or di(hydrogenated)tallow dimethyl ammonium methyl sulfate.

8. The multi-layered tissue paper web of any of Claims 1 - 7 wherein the weight ratio of the quaternary ammonium to the polyhydroxy compound ranges from 1.0: 0.3 to 0.3: 1.0, preferably from 1.0:
0.7 to 0.7: 1Ø

9. A multi-ply tissue paper product comprising at least two juxtaposed multi-layered tissue paper webs of Claim 1, wherein said multi-ply tissue paper product preferably comprises two plies, wherein each of two said plies preferably comprises two superposed layers, and wherein said quaternary ammonium compound is di(hydrogenated)tallow dimethyl chloride or methylsulfate, said polyhydroxy compound is polyoxyethylene glycol having a weight average molecular weight of from 200 to 600, and said binder materials are permanent wet strength resins and temporary wet resins, wherein the majority of said quaternary ammonium compound and said polyhdroxy compound are contained in at least one of said outer layers and wherein the majority of said binder material is contained in said inner layer.

10. The multi-layered tissue paper web of any of Claims 1 - 9 wherein said tissue paper web is a toilet tissue or a facial tissue.