CN1163645A - Paper products containing vegetable oil based chemical softening composition - Google Patents

Abstract

Fibrous cellulose materials useful in the manufacture of soft, absorbent paper products such as paper towels, facial tissues, and toilet tissue are disclosed. The paper products contain a vegetable oil based quaternary ammonium chemical softening compound. Examples of preferred vegetable oil based quaternary ammonium chemical softening compounds include dioleyldimethyl ammonium chloride (i.e., di(octadec-z-9-enyl)dimethylammonium chloride) (DODMAC) and dierucyldimethyl ammonium chloride (i.e., di(docos-z-13-enyl)dimethylammonium chloride) (DEDMAC). Depending upon the paper product characteristic requirements, the saturatiuon level of the fatty acyl groups of the vegetable oils can be tailored. Variables that need to be adjusted to maximize the benefits of using unsaturated vegetable oil based acyl groups include the Iodine Value (IV) of the fatty acyl groups; and the cis/trans isomer weight ratios in the fatty acyl groups.

Description

Paper products containing vegetable oil-based chemical softeners

The present invention relates to tissue paper webs. More particularly, the present invention relates to soft, absorbent tissue paper webs useful in tissue products such as paper towels, napkins, facial tissues, and toilet tissue.

Paper webs or sheets, sometimes called tissue or tissue paper webs or sheets, are used in a wide variety of applications in today's society. Such articles as paper towels, napkins, facial tissues and toilet tissue are major industrial products. Three important physical properties of these products have long been recognized: its flexibility; its absorbency, particularly its absorbency for aqueous systems; and its strength, especially wet strength. Much research and development work has been done with the aim of improving each of these properties without seriously affecting the others and improving two or three properties simultaneously.

Softness is the tactile sensation that a consumer can feel when holding a particular product, rubbing it against the skin, or rubbing it in the hand. This tactile sensation is a combination of several physical properties. One of the more important physical properties, which relates to softness, is considered by those skilled in the art to be the stiffness of the paper web used to make the product. While stiffness is generally considered to be directly dependent on the dry tensile strength of the web and the stiffness of the fibers from which the web is made.

Strength is the ability of an article and its constituent webs to maintain their physical integrity and inhibit tearing, embrittlement and shredding under service conditions, particularly wet conditions.

Absorbency is the ability to measure the amount of liquid (particularly aqueous solutions and dispersions) that an article and its constituent web absorb. The total absorbency perceived by the consumer is generally considered to be the combination of the total amount of liquid absorbed when a given amount of tissue reaches saturation and the rate at which the given amount of tissue absorbs liquid.

The use of wet strength resins to increase the strength of paper webs is well known. For example, Westfelt describes a number of such substances and discusses their chemical properties in Cellulose Chemistry and technology, Vol.13, pp.813-825 (1979). U.S. patent No.3,755,220 issued to Freimark et al at 8/28 1973 mentions that certain chemical additives known as debonding agents (debonding agents) interfere with the natural fiber-to-fiber bonding that occurs during sheet formation in the papermaking process. The reduction in bonding results in a softer or less coarse sheet. Freimark et al then describes the use of wet strength resins to enhance the wet strength of the paper sheet, while employing debonders to counteract the undesirable effects of the wet strength resin. These debonders do reduce the dry tensile strength, but also generally reduce the wet tensile strength.

United states patent number 3,821,068 issued by Shaw at 28/6 1974 also describes that chemical debonding agents may be used to reduce stiffness and thereby increase the softness of the tissue web.

A number of chemical debonding agents have been disclosed in a number of references, such as U.S. Pat. No.3,554,862 issued to Hervey et al at 12.1.1971. These include quaternary ammonium salts such as trimethyl cocoa ammonium chloride, trimethyl oleoyl ammonium chloride, di (hydrogenated) tallow dimethyl ammonium chloride and trimethyl stearyl ammonium chloride.

U.S. patent No.4,144,122 issued to emaguelson et al on 3/13 of 1979 describes the use of complex quaternary ammonium compounds such as bis (alkoxy (2-hydroxy) propylene) quaternary ammonium chloride to soften paper webs. These authors also attempted to overcome the decrease in absorption caused by the debonder by using nonionic surfactants such as the adductsof fatty alcohols with ethylene oxide and propylene oxide.

Armak corporation of Chicago, Illinois, in its publication 76-17(1977) discloses the use of dimethyl di (hydrogenated) tallow ammonium chloride in combination with polyethylene glycol fatty acid esters to impart softness and absorbency to tissue webs.

A typical study result for an improved paper web is described in U.S. patent No.3,301,746 to Sanford and Sisson at 31.1.1967. Despite the high quality paper webs produced by the process described in this patent, and despite the commercial success of the products made from these webs, research efforts to find improved products continue.

For example, U.S. patent No.4,158,594 issued to Becker et al on 19.1.1979 describes a process by which a strong, flexible cellulosic sheet is produced. More specifically, they describe that the strength of tissue webs (which may have been softened by the addition of chemical debonding agents) can be enhanced by: one surface of the web is bonded to the finely patterned structured creping surface during processing by an adhesive material, such as an acrylic latex rubber emulsion, a water soluble resin or an elastomeric adhesive material, which has been bonded to one surface of the web and to the finely patterned structured creping surface, and the web is creped from the creping surface to form the sheet material.

Conventional quaternary ammonium salt compounds, such as the well-known dialkyl dimethyl ammonium salts (e.g., ditallow dimethyl ammonium chloride, ditallow dimethyl ammonium methyl sulfate, di (hydrogenated) tallow dimethyl ammonium chloride, etc.) are effective chemical softeners. Unfortunately, these quaternary ammonium compounds can have odor problems and are difficult to diffuse. The applicant has found that vegetable oil based quaternary ammonium salts are also effective as chemical softeners for enhancing thesoftness of fibrous cellulosic materials. Tissue paper made with the vegetable oil based quaternary ammonium salt softener has good softness and absorbency and improved odor compared to animal oil based quaternary ammonium salt softeners. In addition, due to the good fluidity (low melting point) of the vegetable oil-based quaternary ammonium salt softener, better dispersibility can be obtained with a minimum amount of diluent or without diluent.

It is an object of the present invention to provide a soft, absorbent tissue product.

It is another object of the present invention to provide a soft, absorbent tissue product.

It is yet another object of the present invention to provide a soft, absorbent tissue product.

It is a further object of the present invention to provide a process for making soft, absorbent tissue (i.e., facial and/or bath tissue) and towel products.

These and other objects, which will become apparent from the following description, are achieved by the present invention.

The present invention provides soft, absorbent paper products. Briefly, the soft paper product comprises:

(a) cellulosic papermaking fibers; and

(b) from about 0.005% to about 5.0% by weight of said cellulosic papermaking fiber of a quaternary ammonium salt softening compound having the formula:

(R)_4-m-N⁺-[R²]_mX^-

wherein m is 1-3;

each R is C₁-～C₆Alkyl, hydroxyalkyl, hydrocarbyl, substituted hydrocarbyl, benzyl, or mixtures thereof;

each R²Is C₁₁～C₂₃Hydrocarbyl or substituted hydrocarbyl substituents; and

x-is any emollient compatible anion;

wherein R of the softening composition²Derived in part from C having an iodine value greater than about 5 and less than about 100₁₂～C₂₄A fatty acyl group. Preferably, the majority of the fatty acyl groups are derived from a vegetable oil source.

Preferably, the quaternary ammonium compound is diluted with the liquid carrier to a concentration of about 0.01% to about 25% by weight prior to being added to the fibrous cellulosic material. Preferably, the temperature of the liquid carrier is in the range of 30 ℃ to 60 ℃. Preferably, at least 20% of the quaternary ammonium compound added to the fibrous cellulose is retained.

Examples of preferred quaternary ammonium salts suitable for use in the present invention include compounds having the general formula:

(CH₃)₂-N⁺-(C₁₈H₃₅)₂X^-and

(CH₃)₂-N⁺-(C₂₂H₄₃)₂X^-

these compounds can be viewed as dioleoyl dimethyl ammonium chloride (i.e., dioctadecyl-z-9-enyl dimethyl ammonium chloride) (DODMAC) and dicaprylyl dimethyl ammonium chloride (i.e., di-docosyl-z-13-enyl dimethyl ammonium chloride) (DEDMAC), respectively. It is to be understood that since the oleoyl and erucyl (erucyl) fatty acyl groups are derived from naturally occurring vegetable oils (e.g., olive oil, rapeseed oil, etc.), small amounts of other fatty acyl groups may also be present. For a discussion of the composition of various naturally occurring vegetable oils, reference is made to the Industrial Oil and Fat Products (Bailey's Industrial Oil and Fat Products), thirdedition, John Wiley and Sons (New York, 1964), which is incorporated herein by reference. The degree of saturation of the vegetable oil fatty acyl groups can be adjusted according to the requirements of the product characteristics.

Briefly, the method of making a tissue web of the present invention comprises the steps of: forming a papermaking furnish from the aforementioned ingredients, depositing the papermaking furnish on a foraminous surface, such as a fourdrinier wire, and removing water from the deposited furnish.

All percentages, ratios and parts herein are by weight unless otherwise indicated.

While the scope of the inventive subject matter is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification, it is believed that the invention will be better understood from a reading of the following detailed description and the accompanying examples.

As used herein, the terms "tissue web, paper sheet, and paper product" all refer to a paper sheet prepared by a process comprising the steps of: forming an aqueous papermaking furnish, depositing the furnish on a porous surface (e.g., on a fourdrinier machine), and removing water from the furnish by gravity or vacuum assisted drainage (with or without pressure) and evaporation.

As used herein, an "aqueous papermaking furnish" is an aqueous slurry of papermaking fibers and chemicals as described below.

The first step of the method of the present invention is to form an aqueous papermaking furnish. The furnish includes papermaking fibers (hereinafter sometimes referred to as wood pulp), and at least one vegetable oil based quaternary ammonium salt compound, all of which are discussed below.

It is contemplated that various types of wood pulp will typically include papermaking fibers for use inthe present invention. However, other cellulose fiber pulps, such as cotton linters, bagasse, rayon, and the like, may also be used, none of which is excluded from the claims of the present invention. Wood pulp for use herein includes chemical pulps such as kraft, sulfite and sulfate pulps as well as mechanical pulps such as groundwood, thermomechanical pulp and chemically modified thermomechanical pulp (CTMP). Wood pulp derived from hardwood and softwood can also be used. Also useful in the present invention are fibers derived from recycled paper, which may include any or all of the above various pulps as well as other non-fibrous materials such as fillers and binders used to facilitate the preparation of virgin paper. Preferably, the papermaking fibers used in the present invention comprise kraft pulp derived from northern softwood. (A) Quaternary ammonium salt compound

The present invention comprises as an essential component from about 0.005% to about 5.0%, more preferably from about 0.03% to about 0.5% (by weight of dry fiber) of a quaternary ammonium compound having the formula:

(a) cellulosic papermaking fibers; and

(b) from about 0.005% to about 5.0% by weight of said cellulosic papermaking fibers of a quaternary ammonium salt softening compound having the formula:

(R)_4-m-N⁺-[R²]_mX^-wherein

m is 1 to 3;

each R substituent being a short chain C₁～C₆(preferably C)₁～C₃) Alkyl groups such as methyl (most preferred), ethyl, propyl, and the like, hydroxyalkyl, hydrocarbyl, substituted hydrocarbyl, benzyl, or mixtures thereof;

each R²Is long chain at least partially unsaturated (iodine number (IV) of greater than about 5 to less than about 100, preferably about 10-85), C₁₁～C₂₃Hydrocarbyl or substituted hydrocarbyl substituent and counterion X^-Can be any softener-compatible anion, e.g., acetate, chloride, bromide, methylsulfate, formate, sulfate, nitrate, and the like.

Preferably, a majority of R²Comprises at least 90% C₁₈～C₂₄Fatty acyl groups of chain length. More specifically, most of R²Selected from the group consisting of₁₈、C₂₂And mixtures thereof.

Quaternary ammonium compounds prepared entirely from saturated acyl groups are excellent softeners. However, it has now been found that compounds prepared using at least partially unsaturated acyl groups derived from vegetable oil sources (i.e., having an iodine value of from about greater than 5 to about less than 85, more preferably from about 10 to 85) provide a number of benefits (e.g., better flow) and are highly acceptable products to consumers when certain conditions are met.

Parameters that must be adjusted to obtain the benefits of using unsaturated acyl groups include: iodine Value (IV) of the fatty acyl group and weight ratio of cis/trans isomers in the fatty acyl group. Any of the IV references below refer to the IV (iodine value) of the fatty acyl group, not the iodine value of the resulting quaternary ammonium compound.

Preferably, these quaternary ammonium compounds are made from fatty acyl groups having an IV of about 5 to 25, preferably about 10 to 25, more preferably about 15 to 20, and a cis/trans isomer weight ratio of greater than about 30/70, preferably greater than about 50/50, more preferably about 70/30; these compounds are stable when stored at low temperatures. These cis/trans isomer weight ratios provide the best concentration properties within these IV ranges. At IV ranges greater than about 25, the cis/trans isomer ratio is less critical unless higher concentrations are desired. The relationship between IV and concentration properties is described below.

Generally, fatty acids are hydrogenated to reduce polyunsaturation and to reduce IV to ensure better color conductivityResulting in a higher degree of trans-configuration in the molecule. Thus, quaternary ammonium salt compounds derived from fatty acyl groups having lower IV values can be prepared by mixing fully hydrogenated fatty acids with contact hydrogenated fatty acids in a ratio that provides about 5-25 IV. The contact hardened fatty acid should have a polyunsaturated content of less than about 30%, preferably less than about 10%, more preferably less than about 5%. As used herein, these polyunsaturated percentages refer to polyunsaturated fatty acids (or fatty acyl groups) per 100 groups) The number of (2). The weight ratio of cis/trans isomers during contact hardening can be determined by methods known in the art, such as optimal mixing, use of specific catalysts and provision of sufficient H₂And so on. Synthesis of quaternary ammonium salt compound

The synthesis of the preferred quaternary ammonium compounds for use herein can be obtained by the following two-step process: step A Synthesis of amine

RCl ═ derived from oleic acid or sinapinic acid amines

In a 22 l three-necked flask equipped with an addition funnel, thermometer, mechanical stirrer, condenser and argon purge, N-methyldiamine (440.9 g, 3.69 mol) and triethylamine (561.2 g, 5.54 mol) were dissolved in CH₂Cl₂(12L). Fatty acid chlorides based on vegetable oils (2.13 kg, 7.39 mol) were dissolved in 2l of CH₂Cl₂And slowly added to the amine solution. The amine solution was then heated to 35 ℃ to retain the fatty acid chloride in solution as it was added. The addition of acid chloride increased the reaction temperature to reflux temperature (40 ℃). The addition of the acid chloride should be slow enough to maintain reflux, but not so fast that the methylene chloride escapes from the top of the condenser. The addition of acid chloride was maintained for 1.5 hours. The solution was heated under reflux for an additional 3 hours. The heating was stopped and the reaction solution was stirred for 2 hours to cool to room temperature. Adding CHCl₃(12 liters). With 1 gallon of saturated NaCl and 1 gallon of saturated Ca (OH)₂The solution is washed. The organic layer was allowed to stand at room temperature overnight. Then using 50% K₂CO₃Three extractions (2 gallons each). Then washed twice with saturated NaCl (2 gallons each). Any emulsion formed during these extractions can be made by adding CHCl₃And/or saturated salts and dissolved by heating on a steam bath. The organic layer was then washed with MgSO₄Drying, filtering and concentrating. Yield 2.266 kg oleoyl or erucyl precursor amine, silica gel Thin Layer Chromatography (TLC) (75% ether/25% hexane with a spot at Rf value 0.69).

Step B quaternization

Oleoyl/erucyl precursor amine (2.166 kg, 3.47 moles) and CH₃CN was heated on a steam bath until it became liquid. The mixture was then poured into 10 gallons of a solution containing CH₃CN (4 gallon) glass lined, stirred Pfaudler reactor. Addition of CH through test tube₃Cl (25 lbs, liquid), and the reaction was heated to 80 ℃ for 6 hours. Will CH₃The CN/amine solution was removed from the reactor, filtered and the solid was dried at room temperature for about one week. The filtrate was rotary evaporated, allowed to air dry overnight and combined with other solids. Yield: 2.125 kg of white powder.

The quaternary ammonium salt compound can also be synthesized by other methods:

0.6 mol of diethanol methylamine was placed in a 3 l three-necked flask equipped with a reflux condenser, argon (or nitrogen) inlet and two addition funnels. 0.4 moles of triethylamine was placed in one addition funnel and 1.2 moles of 1: 1 CH of erucyl chloride was placed in the second addition funnel₂Cl₂In the solution of (1). Will CH₂Cl₂(750ml) was added to a reaction flask containing the amine and heated to 35 deg.C (water soluble). Triethylamine was added dropwise and the temperature was raised to 40-45 ℃ with stirring over 1.5 hours. Dropwise adding a mustard chloride/dichloromethane solution, and heating the reaction solution at 40-45 ℃ overnight (12-16 hours) in an inert gas.

The reaction mixture was cooled to room temperature and diluted with chloroform (1500 ml). The chloroform solution of the product was placed in a separatory funnel (4 liters) and diluted with saturated NaCl, Ca (OH)₂、50％K₂CO₃(three times)^*Washing, and finally washing with saturated NaCl. Collecting the organic layer, using MgSO₄Dried, filtered and the solvent removed by rotary evaporation. Final drying (0.25mmHg) was performed under high vacuum.^*Note: 50% K₂CO₃The layer was underneath the chloroform layer. Step B Quaternary amination

Mixing the methyldiethanol erucic acid ester amine obtained in the step A with 200 to up to one300 ml acetonitrile (anhydrous) were put together into the autoclave cannula. The sample was then inserted into the autoclave and treated with N₂Degassing (16275mmHg/21.4 atm) three times with CH₃Cl was exhausted once. Reacting the mixture with CH₃The mixture was heated to 80 ℃ for 24 hours under a Cl pressure of 3604mmHg/4.7 atm. The autoclave cannula was then removed from the reaction mixture. The sample was dissolved in chloroform and the solvent was removed by rotary evaporation, followed by drying under high vacuum(0.25mmHg)。

Another method that may be used commercially to prepare the preferred quaternary ammonium compounds is to react a fatty acid (e.g., oleic acid, erucic acid) with methyldiethanolamine. The amine precursor may be formed by known reaction methods. As discussed previously, quaternary ammonium salts can be formed by reaction with methyl chloride.

The reaction methods described above are well known in the art for preparing quaternary ammonium softening compounds. Other changes to these processes are generally necessary to achieve the IV, cis/trans ratio, and percent unsaturation set forth above.

Several types of vegetable oils (e.g., olive oil, rapeseed oil, safflower oil, sunflower oil, soybean oil, meadow foam oil, etc.) can be used as the fatty acid source to synthesize the quaternary ammonium salt compound. Preferably, olive oil, Douglas oil, safflower oil with a high oleic acid content and/or rapeseed oil with a high erucic acid content are used to synthesize the quaternary ammonium compounds. Most preferably, high erucic acid derived from rapeseed oil is used to synthesize the quaternary ammonium salt compound. It is to be understood that since fatty acyl groups are derived from naturally occurring vegetable oils (e.g., olive oil, rapeseed oil, etc.), small amounts of other fatty acyl groups may also be present. For a discussion of the various components of naturally occurring vegetable oils, see Bailey's Industrial Oil and FatProducts, third edition, John Wiley and Sons (New York 1964), incorporated herein by reference.

Importantly, it has been found that the vegetable oil based quaternary ammonium salt compounds of the present invention can be dispersed without the use of dispersing aids such as wetting agents. Without being bound by theory, it is believed that their excellent dispersability is due to the good fluidity (low melting point) of the vegetable oils. This is in contrast to conventional animal fat based quaternary ammonium compounds which require a dispersing aid due to a relatively high melting point. Vegetable oils also provide improved oxidative and hydrolytic stability. In addition, tissue paper made with vegetable oil-based softeners exhibit good softness and absorbency and improved odor performance as compared to tissue paper made with animal oil-based softeners.

The present invention is generally applicable to tissue papers, including but not limited to conventional felt pressed tissue papers; pattern-densified tissue paper such as exemplified by the aforementioned U.S. patents to Sanford-Sisson and descendants thereof; and high bulk, uncompacted tissue papers, such as exemplified by U.S. patent No. 5/21 1974 issued to salvuci, jr. The tissue paper may be in a homogeneous or multi-ply structure; the tissue paper thus produced may be of single-ply or multi-ply construction. Tissue structures formed from layered webs are described in U.S. patent 3,944,771 issued to Morgan, Jr et al, 11/30 1976, which is incorporated herein by reference. In general, wet laid (wet-laid) composite, soft, bulky and absorbent paper structures are made up of two or more plies preferably containing different fiber typesAnd (4) preparing the material. The layers are preferably prepared from separate streams of dilute fiber slurry deposited on one or more endless foraminous screens, the fibers typically being relatively long softwood and relatively short hardwood fibers used in tissue paper manufacture. The layers are then combined to form a layered composite web. The web is then forced by the application of a fluid against the surface of an open mesh dryer/impression fabric, followed by thermal predrying on the fabric as part of the low density papermaking process. The layered web may be layered according to fiber type or the fiber content of the layers may be substantially the same. The basis weight of the tissue paper is preferably 10g/m²To about 65g/m²The density is about 0.60 g/cc or less than 0.60 g/cc³. Preferably, the quantitative amount is 35g/m²Or 35g/m²The following; density of about 0.30 g/cm³Or less than 0.30 g/cm³. Most preferably, the density is 0.04 g/cm³To about 0.20 g/cm³In the meantime.

Conventionally pressed tissue papers and methods for making such papers are well known in the art. Such papers typically have papermaking furnish deposited on a foraminous forming wire. The forming wire is known in the art as a fourdrinier wire. Once the furnish is deposited on the forming wire, the furnish is referred to as a web. The web is dewatered by pressing the web and drying at elevated temperatures. Specific techniques and typical equipment for making a paper web according to the above described method are well known in the art. In a typical process, a low consistency pulp furnish is provided by a pressurized headbox. The headbox has an opening for delivering thin deposits of the pulp furnish to the fourdrinier wire to form a wet paper web. The web is then typically dewatered to a fiber consistency of about 7% to 25% by vacuum dewatering (based on total web weight) and further dried by a pressing operation in which the web is subjected to pressure from opposed mechanical elements, such as cylindrical rolls.

The dewatered web is then further pressed and dried using steam dryer means known in the art, such as a yankee dryer. The pressure pressing of the web on the yankee dryer can be generated by mechanical means, such as a cylinderroll against the web. Vacuum may also be applied to the web as it is pressed against the yankee surface. It is also possible to apply several yankee dryers, with an optional additional press occurring between these dryers. The resulting tissue structure is hereinafter referred to as a conventional, pressed tissue structure. Such sheets are generally considered to be consolidated because the web is subjected to substantial overall mechanical compression forces while the fibers are in a wet state, and then the web is dried (and optionally creped) while the web is in a compressed state.

Pattern densified tissue paper is characterized by having relatively high loft regions of relatively low fiber density and a series of densified regions of relatively high fiber density. On the other hand, the high loft region is characterized in that it is pillow-shaped regions (pillow regions). And the dense regions are referred to as knuckle regions. The densified regions can be distributed discretely within the high-expansion region or can be connected in whole or in part within the high-expansion region. Preferred methods of making a densified patterned tissue web are disclosed in the following patents: U.S. patent No.3,301,746 to Sanford and Sisson, 31/1/1967; U.S. patent No.3,974,025 to pererg. eyers at 8/10 1976; U.S. patent No.4,191,609 issued to Paul d.trokhan on 3/4 1980 and U.S. patent 4,637,857 issued to Paul d.trokhan on 1/20 1987; all of the above patents are incorporated herein by reference.

Generally, a dense pattern web is preferably formed by depositing a papermaking furnish on a foraminous forming wire (e.g., fourdrinier wire) to form a wet web, and then juxtaposing the web on a series of supports. The web is then pressed against a series of supports to form densified regions in the web corresponding geographically to the location of the point of contact between the propagation support and the wet paper web. The remaining portion of the web that is not compressed during this operation is referred to as the high loft zone. The high-bulk zone may be further densified by application of fluid pressure, such as by a vacuum-type device or blow-through dryer, or by mechanically pressing the web against a support system. The web is dewatered and optionally predried in such a way that compression of the high expansion bulk region is substantially avoided. This is preferably accomplished by fluid pressure, such as with a vacuum type device or blow dryer, or by mechanically compressing the web on a series of supports (wherein the high loft regions are not compressed). The dewatering operation, optional pre-drying, and compacting zone forming processes may be combined or partially combined to reduce the total number of processing steps performed. After formation of the densified regions, dewatering, and optional pre-drying, the web is completely dried, preferably while still avoiding mechanical pressing. Preferably, about 8-55% of the surface of the tissue paper comprises densified joint regions having a relative density of at least 125% of the density of the high loft region.

The series of supports is preferably an embossed support fabric having patterned displacement knuckles that act as a series of supports to aid in the formation of densified regions when pressure is applied. The pattern of joints constitutes the series of supports referred to above. Imprinting carrier fabrics are disclosed in the following patents: U.S. patent No.3,301,746 to Sanford and Sisson, 31/1/1967; U.S. patent No.3,821,068 issued to Salvucci, Jr et al, on 21/5/1974; U.S. Pat. No.3,974,025 to Ayers, 8/10 1976; U.S. Pat. Nos. 3,573,164 to Friedbery et al, 1971, 3, 30; U.S. patent No.3,473,576 issued to Amneus on 21/10/1969; U.S. patent No.4,239,065 issued to Trokhan at 16.12.1980 and U.S. patent No.4,528,239 issued to Trokhan at 9.7.1985, all of which are incorporated herein by reference.

Preferably, the furnish is first formed into a wet web on a porous forming support, such as a fourdrinier wire. The web is dewatered and transferred to an impression fabric. Alternatively, the furnish may be initially deposited on a porous support carrier which also serves as the impression fabric. Once the wet web is formed, it is dewatered and preferably thermally predried to a selected fiber consistency of between about 40-80%. Dewatering can also be carried out with suction boxes or other vacuum devices or blow dryers. The knuckle imprints of the impression fabric are pressed into the web as previously discussed before the web is completely dried. One way to achieve this is by applying mechanical pressure. This may be done, for example, by pressing a press roll supporting the impression fabric against the surface of a drying drum, such as a yankee dryer. Also, it is preferred that the web be formed onto the impression fabric by the application of vacuum (e.g., suction boxes) or fluid pressure blown into the dryer before the web is completely dried. The indentation of the densified region may be caused by application of fluid pressure during initial dewatering, in a separate, subsequent process step, or a combination of both.

The uncompacted, non-pattern densified tissue structures are described in the following patents: U.S. patent No.3,812,000 issued to Joseph l.salvucci, jr. and Peter n.yiannios on 5/1974 and U.S. patent No.4,208,459 issued to Henry e.becker, Albert l.mcconnell and RichardSchutte on 6/1980 on 17/1974, both of which are incorporated herein by reference. Typically, an uncompacted, non-pattern densified tissue paper is prepared by the following process: the papermaking furnish is deposited onto a foraminous forming wire (e.g., fourdrinier wire) to form a wet paper web, the web is drained and excess water is removed without mechanical compression until the web has a fiber consistency of at least 80%, and the web is creped. Water is removed from the web by vacuum dewatering and thermal drying. The resulting structure is a soft but lower strength sheet of high loft, relatively uncompacted fibers. The bonding material is preferably applied to the web prior to creping.

Densified, unpatterned densified tissue structures are conventional tissue structures well known in the art. Generally, a densified, unpatterned densified tissue paper structure is prepared by the following process: depositing a papermaking furnish on a foraminous wire (e.g., fourdrinier wire) to form a wet paper web, draining the web, removing excess water with the aid of uniform mechanical compression until the web has a consistency of 25-50%, transferring the web to a thermal dryer (e.g., a yankee dryer), and creping the web. In general, water is removed from the web by vacuum, mechanical pressing, and thermal methods. The resulting structure is strong and generally uniform in density, but low in bulk, absorbency, and softness.

The tissue webs of the present invention can be used in any application where a soft, absorbent tissue web is desired. Particularly advantageous applications of the tissue web of the invention are the production of tissue, toilet tissue and facial tissue products. For example, two tissue webs of the present invention can be embossed and secured together in face-to-face relation with an adhesive to form a two-ply tissue as described in U.S. patent No.3,414,459 to Wells, 12, 3, 1968, incorporated herein by reference.

Analysis and testing method

Analysis of the treatment chemicals used in the present invention or the amount of treatment chemicals left on the tissue web can be performed by any method applicable in the art. A. Quantitative analysis of Quaternary ammonium salt Compound

For example, the amount of quaternary ammonium compounds (e.g., dioleoyldimethylammonium chloride (DODMAC), dicaprylyldimethylammonium chloride (DEDMAC)) remaining on the tissue paper can be determined by anion/cation titration using an organic solvent extraction of DODMAC/DEOMAC followed by Dimidium Bromide as an indicator. These methods are intended to be exemplary and not exclusive of other methods that may be used to determine the amount of a particular ingredient retained by the tissue paper. B. Hydrophilicity (absorbability)

The hydrophilicity of tissue paper generally refers to the tendency of tissue paper to be wetted by water. The hydrophilicity of tissue paper can be quantified to some extent by measuring the time required for the dry tissue paper to be fully wetted with water. This time is referred to as the "wet out time". To provide consistent and repeatable wet-out time testing, the following methods may be used to determine wet-out time: first, a conditioned sample unit sheet (measured for paper testing at ambient conditions of 23+1 ℃ and a relative temperature of 50+ 2%, as defined by TAPPI method T402) is provided having a tissue structure of about 4-3/8 inches by 4-3/4 inches (about 11.1cm by 12 cm); in a second step, the sheet is folded into 4 juxtaposed aliquots, which are then rolled into balls having a diameter of about 0.75 inches (about 1.9cm) to about 1 inch (about 2.5 cm); thirdly, placing the spherical paper on the surface of distilled water with the temperature of 23 +/-1 ℃, and simultaneously starting a timer; fourthly, stopping the timer and reading the time when the ball paper sheet is completely wetted. Complete wetting can be observed visually.

Of course, embodiments of the hydrophilicity of the tissue of the present invention can also be measured immediately after manufacture. However, the hydrophilicity of the paper increases significantly during the first two weeks after tissue paper manufacture, i.e., two weeks after manufacture. Therefore, it is best to measure the wetting time at the end of these two weeks. Accordingly, the wet out time measured at the end of the two-week aging period at room temperature is referred to as the "two-week wet out time". C. Density of

The term "density of the tissue paper" as used herein is the average density calculated by dividing the basis weight of the paper by its thickness and performing a suitable unit transformation. As used herein, the caliper of the tissue paper is defined as the caliper received at 95 grams/inch²(15.5 g/cm)²) The thickness of the paper under a compressive load. Optional ingredients

Other chemicals commonly used in papermaking can be added to the chemical softening compositions described herein or to the papermaking furnish so long as they do not significantly and adversely affect the softening, absorbency of the fibrous material and softness enhancement of the quaternary ammonium salt softening compounds of the present invention. A. Wetting agent:

the present invention may contain as an optional component from about 0.005 to 3.0%, more preferably from about 0.03 to 1.0% of a wetting agent based on the weight of the as-spun fibers. (1) Polyhydroxy compounds

Examples of water-soluble polyols that can be used as humectants in the present invention include glycerin, polyglycerols having a weight average molecular weight of about 150 to 800, and polyethylene glycols and polypropylene glycols having a weight average molecular weight of about 200 to 4000, preferably about 200 to 1000, and most preferably about 200 to 600. Polyethylene glycols having a weight average molecular weight of about 200 to 600 are particularly preferred. Mixtures of the above polyols may also be used. One particularly preferred polyol is polyethylene glycol having a weight average molecular weight of about 400. This material is commercially available from Danbury Union carbide, Conn, under the tradename "PEG-400". (2) Nonionic surfactants (alkoxylated substances)

Suitable nonionic surfactants that can be used as wetting agents in the present invention include the addition products of fatty alcohols, fatty acids, fatty amines, and the like, with ethylene oxide and optionally with propylene oxide.

Any of the particular types of alkoxylated materials described below may be used as the nonionic surfactant. Suitable compounds are substantially water-soluble surfactants having the general formula:

R²-Y-(C₂H₄O)_z-C₂H₄OH wherein R is a combination of solid and liquid²Selected from: primary, secondary and branched alkyl and/or acyl hydrocarbyl groups; primary, secondary and branched alkenyl hydrocarbyl; and primary, secondary and branched alkyl and alkenyl substituted phenolic hydrocarbyl groups; the hydrocarbyl group has a hydrocarbon chain length of about 8 to 20, preferably about 10 to 18 carbon atoms. More preferably, the hydrocarbon chain length for liquid compositions is about 16 to 18 carbon atoms, and the hydrocarbon chain length for solid compositions is about 10 to 14 carbon atoms. For the general formula of ethoxylated nonionic surfactants herein, Y is typically-O-, -C (O) -O-, -C (O) N (R) -or-C (O) N (R) R²-, wherein R²And R (if present) has the meaning given above, and/or R may be hydrogen, and z is at least about 8, preferably at least about 10 to 11. When fewer ethoxylated groups are present, the performance and generally the stability of the softener composition is reduced.

The nonionic surfactant herein is characterized by an HLB (hydrophilic lipophilic balance) of about 7 to 20, preferably about 8 to 15. Of course, by definition of R²And the number of ethoxylated groups, the HLB of the surfactant can generally be determined. It should be noted, however, that the nonionic ethoxylated surfactants used herein, for concentrated liquid compositions, contain relatively long chain R²A group, and is relatively highly ethoxylated. Although the shorter alkyl chain surfactants of the short ethoxylated groups have the desired HLB, they are not effective herein.

Examples of nonionic surfactants are listed below. The nonionic surfactant of the present invention is not limited to these examples. In these examples, the integer defines the number of Ethoxy (EO) groups in the molecule. Linear alkoxylated alcohols a. linear primary alcohol alkoxylates

Decyl, undecyl, dodecyl, tetradecyl, pentadecyl ethoxylates of n-cetyl alcohol and n-stearyl alcohol having HLB values within the ranges described herein are useful wetting agents in the sense of the present invention. Examples of ethoxylated primary alcohols useful in the present invention as viscosity/dispersibility modifiers for compositions are n-C₁₈EO (10) and n-C₁₀EO (11). Mixed ethoxylates of natural or synthetic alcohols within the "oleic" chain length range may also be useful in the present invention. Specific examples of such materials include oleyl alcohol-EO (11), oleyl alcohol-EO (18) and oleyl alcohol-EO (25). b. Linear secondary alcohol alkyl hydride

Deca-, undec-, dodeca-, tetradecyl-, pentadeca-, octadeca-, and nonadeca-ethoxylates of 3-hexadecanol, 2-octadecanol, 4-eicosanol, and 5-eicosanol having HLB values within the ranges described herein may be used as wetting agents in the present invention. Examples of ethoxylated secondary alcohols that can be used as wetting agents in the present invention are: 2-C₁₆EO(11)、2-C₂₀EO (11) and 2-C₁₆EO (14). Linear alkylphenoxylated alcohols

For alcohol alkoxylates, alkoxylated phenols, especially hexa-octadecyl ethoxylates of monohydric alkyl phenols having an HLB within the ranges described herein, may be used as viscosity/dispersibility modifiers for the compositions of the present invention. Hexa-octadecyl ethoxylates of p-tridecylphenol and m-pentadecylphenol, and the like, may be used in the present invention. Examples of ethoxylated alkylphenols useful as wetting agents for the mixtures of the present invention are: p-tridecylphenol EO (11) and p-pentadecylphenol EO (18).

The phenylene group in the nonionic structural formula used in the present invention and known in the art is an equivalent of an alkylene group having 2 to 4 carbon atoms. For the purposes of the present invention, nonionic surfactants containing phenylene groups are considered to contain an equivalent number of carbon atoms. The number of carbon atoms is: "calculated as the sum of the number of carbon atoms in the alkyl group plus about 3.3 carbon atoms per phenylene group. Olefinic alkoxylates

Alkenylalcohols (including both primary and secondary) and alkenylphenols corresponding to those disclosed above may be ethoxylated to have their HLB within the ranges described herein for use as wetting agents in the present invention. Branched alkoxylates

Branched primary and secondary alcohols obtained from the well known "OXO" process can be ethoxylated and used as wetting agents in the present invention.

The above ethoxylated nonionic surfactants may be used in the compositions of the present invention, either alone or in combination, and the term "nonionic surfactant" includes mixed nonionic surfactants.

The amount of surfactant used, if used, is preferably from about 0.01% to 2.0% by weight based on the dry fiber weight of the tissue paper. The surfactant preferably has an alkyl chain of 8 or more carbon atoms. Examples of anionic surfactants are linear alkyl sulfonates and alkyl benzene sulfonates. Typical nonionic surfactants are alkyl glycosides including alkyl glycoside esters, such as Crodesta SL-40 available from Croda corporation, New York; alkyl glycoside ethers described in U.S. patent No.4,011,389 to w.k. langdon et al, 3,8, 1977; and alkyl polyethoxylated esters such as Pegosperse 200ML from Glyco Chemicals, Greenwich, Connecticut, and IGEPALRC-520 from Rhone Poulenc, Inc. (Cranbury, N.J.). B. Strength additive

Other types of chemicals that may be added include strength additives to increase the dry tensile strength and wet burst strength of the tissue web. The present invention may contain as an optional component from about 0.01% to 3.0%, more preferably from about 0.3% to 15%, by weight based on the weight of dry fiber, of a water-soluble strength additive resin. (a) Dry strength additive

Examples of dry strength additives include carboxymethyl cellulose and cationic polymers of the Acco chemical series (e.g., Acco711 and Acco 514), with the Acco chemical series being preferred. These materials are commercially available from the American Cyanamide Company of Wayne, N.J. (b) Permanent wet strength additive

The permanent wet strength resins used in the present invention can be of several types. Generally, resins that have been discovered and are hereinafter used in the art of papermaking are useful in the present invention. Examples are shown in the aforementioned Westfelt article, which is incorporated herein by reference.

In general, wet strength resins are water-soluble, cationic materials. That is, when the resin is added to a papermaking furnish, the resin is water soluble. It is very likely, and even expected, that subsequent conditions (such as crosslinking) will render the resin insoluble in water. Moreover, some resins are soluble only under certain conditions (e.g., within a limited pH range).

It is generally believed that wet strength resins will typically undergo crosslinking or other curing reactions after they have been deposited on, within, or between papermaking fibers. The crosslinking or curing reaction generally does not occur as long as a large amount of water is present.

Various polyamide-epichlorohydrin resins are particularly useful. These materials are low molecular weight polymers having reactive functional groups such as amino, epoxy and azetidinium groups. The patent literature is replete with descriptions of methods for the preparation of such materials. U.S. Pat. No.3,700,623, issued to Keim at 24.10.1972, and U.S. Pat. No.3,772,076, issued to Keim at 13.11.1973, are examples of such patents, both of which are incorporated herein by reference.

Polyamide-epichlorohydrin resins sold under the trademarks Kymene557H and Kymene 2064 by Hercules Incorporated of Wilmington, Del are particularly useful in the present invention. These resins are described generally in the aforementioned Keim patents.

The alkali-activated polyamide-epichlorohydrin resins useful in the present invention are sold under the trademark Santo Res, such as Santo Res 31 sold by Monsanto Company of St.Louis, Mo. These types of materials are generally described in the following patents: U.S. patent No.3,855,158 issued to Petrovich at 12.17.1974; U.S. patent No.3,899,388 issued to Petrovich at 8/12/1975; U.S. patent No.4,129,528 issued to Petrovich at 12.12.1978; U.S. patent 4,147,586 issued to Petrovich on 3/4/1979; and U.S. patent 4,222,921 issued to Van Eenam at 9, 16, 1980; all of these patents are incorporated herein by reference.

Other water-soluble cationic resins useful herein are polyacrylamide resins sold under the Parez trademark (e.g., Parez631NC) by cyanamide corporation of Stanford, America Cyanamid Company, Conn. These materials are generally described in the following U.S. patents: patent 3,556,932 issued to Coscia et al at 19.1.1971 and 3,556,933 issued to Williams et al at 19.1.1971, both patents being incorporated herein by reference.

Other types of water-soluble resins useful in the present invention include acrylic emulsions and anionic styrene-butadiene latexes. Many examples of these types of resins are described in U.S. patent 3,844,880 issued to Meisel, jr. et al, 10/29 1974, which is incorporated herein by reference.

Other water-soluble cationic resins useful in the present invention are urea-formaldehyde resins and melamine-formaldehyde resins. These multifunctional, living polymers have a molecular weight of about several thousand. More common functional groups include nitrogen-containing groups such as amino groups and nitrogen-attached hydroxymethyl groups.

Although less preferred, polyethyleneimine type resins can be used in the present invention.

A more complete description of the aforementioned water-soluble resins, including their preparation, can be found In TAPPI monograph Serial No.29, Paper and Paperboard Wet Strength (Wet Strength In Paper and Paperboard), by the Technical Association of Pulp and Paper (TAPPI), New York, 1965, which is incorporated herein by reference. The term "permanent wet strength resin" as used herein refers to a resin that when placed in an aqueous medium, allows the sheet to retain most of its initial wet strength for at least more than two minutes. (C) Temporary wet strength additives

The above-mentioned wet strength additives generally result in paper products having permanent wet strength, i.e. paper which retains a large part of its initial wet strength over time when placed in an aqueous medium. However, permanent wet strength can be an optional and undesirable property in certain types of paper products. Paper products, such as toilet paper and the like, are usually disposed of after entering the humic system after a short period of use. Clogging of these systems can result if the paper product permanently retains its hydrolytic strength properties. For some time recently, manufacturers have added temporary wet strength additives to paper products whose wet strength is sufficient for the intended application, but which decrease when soaked in water. The reduction of wet strength aids the flow of the paper product through the humic system.

Examples of suitable temporary wet strength resins include modified Starch temporary wet strength agents sold by National Starch and chemicals Corporation, new york city, new york (National Starch and Chemical Corporation), such as National Starch 78-0080. Such wet strength agents can be prepared by reacting dimethoxyethyl-N-methyl-chloroacetamide with a cationic starch polymer. Modified starch temporary wet strength agents are also described in U.S. Pat. No.4,675,394 issued to Solarek et al, 6/23 1987, incorporated herein by reference. Preferred temporary wet strength resins include those disclosed in U.S. patent No.4,981,557 issued to Bjorkquist, 1/1991, which is incorporated herein by reference.

With respect to the types and specific examples of permanent and temporary wet strength resins listed above, it should be understood that these resins are exemplary only and are not intended to limit the scope of the present invention.

Mixtures of compatible wet strength resins may also be used in the practice of the present invention.

The optional chemical additives listed above are exemplary only and are not meant to limit the scope of the invention.

The following examples are intended to illustrate the practice of the invention, but are not intended to limit the invention. Example 1

The purpose of this example is to illustrate a process that can be used to prepare an aqueous dispersion of a vegetable oil based quaternary ammonium salt compound, such as dioleoyldimethylammonium chloride (dodec) or dicapryldimethylammonium chloride (depec).

A 2% dispersion of DODMAC was prepared according to the following procedure: 1. measuring a known weight of DODMAC; 2. heating the DODMAC to about 50 ℃ (122 ° F); 3. preconditioning dilution water to pH 3 and about 50 ℃ (122 ° F); 4. thorough mixing was performed to form an aqueous submicron dispersion of the DODMAC softening composition. 5. The particle size of the vesicle dispersion was determined using optical microscopy. The particle size ranges from about 0.1 to 1.0 microns.

A 2% dispersion of DEDMAC was prepared according to the following procedure: 1. measuring a known weight of DEDMAC; 2. heating the DEDMAC to about 50 ℃ (122 ° F); 3. preconditioning dilution water to pH 3 and about 50 ℃ (122 ° F); 4. thorough mixing was performed to form an aqueous submicron dispersion of the DEDMAC softening composition. 5. The particle size of the vesicle dispersion was determined using optical microscopy. The particle size ranges from about 0.1 to 1.0 microns. Example 2

The purpose of this example is to illustrate the process of making soft and absorbent paper towels using blow-dry papermaking technology, which sheets are treated with a chemical softener composition based on a quaternary ammonium salt softener of vegetable oil (DODMAC) and a permanent wet strength resin.

The practice of the invention uses a fourdrinier papermaking machine of small scale. First, a 1% solution of a chemical softener was prepared according to the method of example 1. Next, a 3% (by weight) aqueous NSK (northern softwood kraft) slurry was prepared in aconventional repulper. The NSK slurry was lightly refined by adding a 2% solution of permanent wet strength resin (i.e., Kymene557H sold by Hercules corporation of wilmington, tera) at a rate of 1% dry fiber weight to the NSK feedline. The adsorption of Kymene557H by NSK was enhanced by an in-line mixer. A 1% solution of carboxymethyl cellulose (CMC) was added after the in-line mixer at a ratio of 0.2% dry fiber weight to enhance the dry strength of the fiber matrix. The adsorption of CMC by NSK can be enhanced by an in-line mixer. Then, a 1% solution of chemical softener (DODMAC) was added to the NSK slurry at a rate of 0.1% dry fiber weight. The adsorption of the chemical softener mixture by NSK can also be enhanced by an in-line mixer. NSK was diluted to 0.2% with a fan pump (fan pump). In the third step, 3% by weight CTMP pulp (pre-preg wood chip groundwood) was prepared in a conventional repulper. Nonionic surfactant was added to the repulper at 0.2% dry fiber weight. A 1% solution of a chemical softener mixture was added to the CTMP stock line at a ratio of 0.1% dry weight before the stock pump. The adsorption of the chemical softener mixture by CTMP can be enhanced by an in-line mixer. The CTMP slurry was diluted to 0.2% with a fan pump. The treated furnish blend (NSK/CTMP) is blended and deposited on a fourdrinier wire in a headbox to form a embryonic web. Dewatering is carried out through the fourdrinier wire and with the aid of baffles and vacuum boxes. The fourdrinier wire is a 5-Shed (Shed), satin weave configuration having 84 monofilaments per inch in the machine direction and 76 monofilaments per inch in the cross machine direction, respectively. A wet paper web having a fiber consistency of about 22% was transported from the fourdrinier wire at the draw point over a photopolymer fabric having 240 linear Idaho units per square inch, 34% knuckle area, and 14 mil depth of photopolymer. Further dewatering was accomplished under vacuum assisted draining until the fiber concentration was about 28%. The patterned web was pre-dried by air blowing to a fiber concentration of about 65% by weight. The web was then adhered to the surface of the yankee dryer with a spray creping adhesive containing a 0.25% aqueous solution of polyvinyl alcohol (PVA). The fiber consistency is increased to about 96% before dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 ° and is positioned relative to the yankee dryer to provide an impingement angle of about 81 °; the yankee dryer runs at a speed of about 800 feet per minute (about 244 meters per minute). The dry web was formed into rolls at a speed of 700 feet per minute (214 meters per minute).

The two webs are formed into a tissue product by embossing and laminating using PVA adhesive. The tissue has a basis weight of about 26#/3M Sq Ft, containing about 0.2% chemical softener (DODMAC) and about 1.0% permanent wet strength resin. The resulting tissue is soft, absorbent and strong when wet. Example 3

The purpose of this example is to illustrate the process of making soft and absorbent toilet tissue paper treated with a chemical softener composition of vegetable oil based quaternary ammonium salt softener (DEDMAC) and temporary wet strength resin using blow-drying and layering paper making techniques.

A small scale fourdrinier papermaking machine is used in the practice of the invention. First, a 1% solution of chemical softener was prepared according to the method of example 1. In the second step, a 3% (by weight) aqueous slurry of NSK is prepared in a conventional repulper. The NSK slurry was lightly refined and a 2% solution of temporary wet strength resin (i.e., National Starth 78-0080 sold by National starch and chemicals, inc. of new york, new york city) was added to the NSK infusion line at a rate of 0.75% dry fiber weight. The temporary wet strength resin adsorption on the NSK fibers is enhanced by an in-line mixer. The NSK slurry wasdiluted to a concentration of about 0.2% at the fan pump. In a third step, an aqueous slurry of 3% by weight eucalyptus fibers is prepared in a conventional repulper. A 1% solution of a chemical softener mixture was added to the eucalyptus pulp line in a proportion of 0.2% dry fibre weight before the pulp pump. The adsorption of the chemical softener mixture to eucalyptus fibers is enhanced by an in-line mixer. The eucalyptus slurry was diluted to a concentration of about 0.2% at the fan pump.

The treated furnish mixture (30% NSK/70% eucalyptus) was mixed in a head box and deposited on a fourdrinier wire to form a embryonic web. Dewatering is carried out through the fourdrinier wire and with the aid of baffles and vacuum boxes. The fourdrinier wire is of a 5-shed, satin weave configuration having 84 and 76 monofilaments per inch in the machine and cross-machine directions, respectively. At the draw point, a wet embryonic web having a fiber consistency of about 15% was transferred from a photopolymer wire onto a photopolymer fabric having 562 linear Idaho cells per square inch, 40% knuckle area, and 9 mil depth of photopolymer. Further dewatering is accomplished by vacuum assisted drainage until the web has a fiber consistency of about 28%. The patterned web was further pre-dried by air blowing to a fiber concentration of about 65% by weight. The web was then adhered to the yankee dryer surface with a spray creping adhesive containing an aqueous solution of 0.25% polyvinyl alcohol (PVA). The fiber consistency was increased to the expected 96% prior to dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 ° and is positioned relative to the yankee dryer to provide an impingement angle of about 81 °; the yankee dryer runs at a rate of about 800 feet per minute (about 244 meters per minute). The dried web was formed into rolls at a rate of 700 feet per minute (214 meters per minute).

The web is converted into a single ply tissue product. The tissue paper has a basis weight of about 18#/3M Sq Ft, and contains about 0.1% vegetable oil based quaternary ammonium salt softener (DEOMAC) and about 0.2% temporary wet strength resin. Importantly, the resulting tissue paper is soft, absorbent and suitable for use as facial and/or toilet tissue. Example 4

The purpose of this example is to illustrate the process of making soft and absorbent toilet paper treated with a vegetable oil based quaternary ammonium salt softener (DEDMAC) and a dry strength additive resin using a blow-dry papermaking technique.

A small scale fourdrinier papermaking machine is used in the practice of the invention. First, a 1% solution of a chemical softener was prepared according to the method of example 1. Next, a 3% (by weight) aqueous slurry of NSK was prepared in a conventional repulper. The NSK slurry was gently refined and 2% dry strength resin (i.e., aco 514 and aco 711, sold by American Cyanamid company, Fairfield, ohio) was added to the NSK feedline at a rate of 0.2% dry fiber weight. Adsorption of the dry strength resin on the NSK fibers is enhanced by an in-line mixer. The NSK slurry was diluted to a concentration of about 0.2% at the fan pump. In a third step, an aqueous slurry of 3% by weight eucalyptus fibers is prepared in a conventional repulper. A 1% solution of chemical softener was added to the eucalyptus pulp line at a rate of 0.2% dry fibre weight before the pulp pump. The adsorption of the chemical softener by the eucalyptus fibers can be enhanced by an in-line mixer. At the fan pump, the eucalyptus slurry was diluted to a concentration of about 0.2%.

The treated furnish mixture (30% NSK/70% eucalyptus) was mixed in a head box and deposited on a fourdrinier wire to form a embryonic web. Dewatering is carried out through the fourdrinier wire and with the aid of baffles and vacuum boxes. The fourdrinier wire is of a 5-shed, satin weave configuration having 84 and 76 filaments in the machine and cross-machine directions, respectively. At the draw point, a wet embryonic web having a fiber concentration of about 15% was delivered from the photopolymer web to a photopolymer fabric having 562 linear Idaho cells per square inch, 40% knuckle area, and 9 mil depth of photopolymer. Further dewatering was achieved by vacuum assisted drainage until the web had a fiber consistency of about 28%. The patterned web was pre-dried by air blowing to a fiber concentration of about 65% by weight. The web was then bonded to the surface of the yankee dryer with a spray creped adhesive containing a 0.25% aqueous solution of polyvinyl alcohol (PVA). The fiber consistency was increased to the expected 96% prior to dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 ° and is positioned relative to the yankee dryer to provide an impingement angle of about 81 °; the yankee dryer runs at a speed of about 800 feet per minute (about 244 meters per minute). The dry paper web was wound onto a winder at a speed of 700 feet per minute (214 meters per minute).

Two webs are made into tissue products using ply bonding techniques and laminated together. The tissue paper has a basis weight of about 23#/3M Sq Ft, and contains about 0.1% chemical softener (DEDMAC) and about 0.1% dry strength resin. Importantly, the resulting tissue paper is soft, absorbent and suitable for use as facial and/or toilet tissue. Example 5

The purpose of this example is to illustrate the process of making soft and absorbent toilet tissue paper treated with vegetable oil based quaternary ammonium salt softener (DEDMAC) and dry strength additive resin using conventional dry paper making techniques.

A small scale fourdrinier papermaking machine is used in the practice of the invention. First, a 1% solution of a chemical softener was prepared according to the method of example 3. In the second step, a 3% (by weight) aqueous slurry of NSK is prepared in a conventional repulper. The NSK slurry was lightly refined and a 2% dry strength resin solution (i.e., acc 514, acc 711, sold by American Cyanamid company of Wayne, nj) was added to the NSK delivery line at a rate of 0.2% dry fiber weight. Adsorption of the dry strength resin on the NSK fibers is enhanced by an in-line mixer. The NSK slurry was diluted to a concentration of about 0.2% at the fan pump. In a third step, an aqueous slurry of 3% by weight eucalyptus fibers is prepared in a conventional repulper. A 1% solution of chemical softener was added to the eucalyptus pulp line at a rate of 0.2% dry fibre weight before the pulp pump. The adsorption of the chemical softener mixture by the eucalyptus fibers can be enhanced by an in-line mixer. At the fan pump, the eucalyptus slurry was diluted to a concentration of about 0.2%.

The treated furnish mixture (30% NSK/70% eucalyptus) was mixed in a head box and deposited on a fourdrinier wire to form a embryonic web. Dewatering is carried out through the fourdrinier wire and with the aid of baffles and vacuum boxes. The fourdrinier wire is a 5-shed, satin weave configuration having 84 and 76 monofilaments per inch in the machine and cross-machine directions, respectively. At the pick-up, a wet paper web having a fiber consistency of about 15% is transferred from a fourdrinier wire to a conventional felt. Further dewatering was achieved by vacuum assisted draining until the web had a fiber consistency of about 35%. The web is then bonded to the surface of the yankee dryer. The fiber concentration was increased to the expected 96% before dry creping the web with a doctor blade. The doctor blade has a bevel angle of about 25 ° and is positioned relative to the yankee dryer to provide an impingement angle of about 81 °; the yankee dryer runs at about 800 feet per minute (about 244 meters per minute). The dry paper web was wound onto a winder at a speed of 700 feet per minute (214 meters per minute).

Two webs are made into tissue products using ply bonding techniques and laminated together. The tissue paper has a basis weight of about 23#/3M Sq Ft, and contains about 0.1% chemical softener (DEDMAC) and about 0.1% dry strength resin. Importantly, the resulting tissue paper is soft, absorbent and suitable for use as facial and/or toilet tissue.

Claims (24)

1. A soft paper product comprising:

(a) cellulosic papermaking fibers; and

(b) from about 0.005% to about 5.0% by weight of said cellulosic papermaking fiber of a quaternary ammonium softening compound of the formula:

(R)_4-m-N⁺-[R²]_mX^-wherein

m is 1 to 3;

each R is C₁～C₆Alkyl, hydroxyalkyl, hydrocarbyl, substituted hydrocarbyl, benzyl, or mixtures thereof;

each R²Is C₁₁～C₂₃Hydrocarbyl or substituted hydrocarbyl substituents; and

x-is any emollient compatible anion;

wherein R of the softening compound²Partially derived from C having an iodine value of greater than about 5 to less than about 100₁₂～C₂₄A fatty acyl group.

2. The paper product according to claim 1, wherein a majority of said fatty acyl groups are derived from a vegetable oil source.

3. A paper product according to claim 2 wherein said fatty acyl groups have an iodine value of from about 10 to about 85.

4. The paper product according to claim 3 wherein said fatty acyl groups have a cis/trans isomer weight ratio of greater than about 50/50.

5. The paper product according to claim 3, wherein a majority of R²Comprises at least 90% C₁₈～C₂₄Fatty acyl groups of chain length.

6. The paper product according to claim 5, wherein a majority of R²Comprises at least 90% C₁₈The fatty acyl group of (1).

7. The paper product according to claim 5, wherein a majority of R²Comprises at least 90% C₂₂The fatty acyl group of (1).

8. The paper product of claim 1, further comprising from about 0.005% to about 3.0% of a wetting agent.

9. The paper product of claim 8 wherein said humectant is a water-soluble polyol.

10. The paper product of claim 8 wherein said wetting agent is a linear alkoxylated alcohol.

11. The paper product of claim 8 wherein said wetting agent is a linear alkyl-phenoxylated alcohol.

12. The paper product according to claim 2, wherein each R is C₁～C₃An alkyl group.

13. The paper product according to claim 12, wherein each R is methyl.

14. The paper product according to claim 2, wherein m-2.

15. The paper product according to claim 3, wherein the fatty acyl groups have a degree of polyunsaturation of less than about 30%.

16. The paper product according to claim 15, wherein the fatty acyl groups have a degree of polyunsaturation of less than about 10%.

17. The paper product according to claim 12, wherein X is selected from the group consisting of chloride, acetate, methylsulfate, and mixtures thereof.

18. The paper product according to claim 6, wherein a majority of said fatty acyl groups based on vegetable oil are derived from olive oil.

19. The paper product according to claim 7, wherein a majority of said vegetable oil-based fatty acyl groups are derived from rapeseed oil.

20. A paper product according to claim 6 wherein a substantial portion of said vegetable oil based fatty acyl groups are derived from high oleic safflower oil.

21. The paper product according to claim 7, wherein a majority of said fatty acyl groups based on vegetable oil are derived from Dolichos oil.

22. The paper product according to claim 1, wherein said paper product is a tissue.

23. The paper product according to claim 1, wherein said paper product is a facial tissue.

24. The paper product according to claim 1, wherein said paper product is toilet paper.