MXPA01003891A - Compositions and methods for preparing dispersions and methods for using the dispersions - Google Patents

Abstract

Compositions and methods useful as stabilizing dispersions containing paper sizing agents are provided. The dispersions comprise a hydrophobically modified water-soluble polymer having a viscosity average molecular weight less than about 200,000. Dispersions containing sizing agents and other agents for treating paper can be made according to the methods of the invention.

Description

COMPOSITIONS AND METHODS FOR PPEPARATING DISPERSIONS AND METHODS FOR USING DISPERSIONS BACKGROUND OF THE INVENTION The present invention relates to compositions and methods for preparing dispersions. The new printing processes such as ink jet printing have led to a demand for paper having specific properties while being useful for multiple purposes such as reprographic copying. laser printing inkjet printing, and the like Specialty papers have been developed for each type of application but as a practical matter a multipurpose paper suitable for all such uses is desirable In particular the demands of jet printing ink that both the ink and the paper function in such a way as to provide an acceptable image by wet printing, and acceptably rapid drying of the ink. Additives and agents including sizing agents are commonly used to impart to the paper some of the necessary properties for application is such as inkjet printing Paper is made with and / 3 surface treated with sizing agents mainly & ^? s & amp; amp; x ^^ m to prevent excess penetration, wicking or dispersion of water or ink Many different types of non-reactive and reactive sizing agents are well known in the automotive industry. papermaking Paper sizing agents are often provided in the form of aqueous dispersions. These dispersions may contain one or more sizing agents, one or more salts, and one or more processing aids. During use or short term storage. , the dispersions containing sizing agents and salts can be stratified resulting in an upper layer containing a higher than average concentration of the sizing agent and a lower layer containing a concentration higher than the average of salts. This is a significant disadvantage due to that frequent or continuous agitation may be required in order to maintain a substantially uniform dispersion The stratification of beef sizes Liquid turpentine has been addressed in US Pat. No. 2,873,203, the disclosure of which is hereby incorporated by reference in its entirety. The method described for inhibiting stratification includes the addition to the turpentine resin sizing of a • a small amount of sodium chloride, vg, up to about 5% based on the total weight of the solids in the sizing. However, the data indicates that even when the stratification can be eliminated for 2 days with the addition of up to 5 % Sodium Chloride The addition of more sodium chloride can lead to the salification of sodium chloride instead of the extension of the period during which stratification is prevented. The present invention provides compositions and methods for forming dispersions that can remain substantially uniform during use and / or storage The compositions and methods are useful in dispersions of materials such as sizing agents for paper.

SUMMARY OF THE INVENTION One aspect of the present invention is a composition comprising a paper sizing agent and at least one hydrophobically modified water-soluble polymer having a viscosity average molecular weight of about 200,000 or less In preferred embodiments the soluble polymer in hydrophobically modified water has a viscosity average molecular weight of about 100,000 or less ii ^ &t? M ^^. ^ i-? '*, -.

- TO - more preferably of about 50,000 or less Likewise preferably a hydrophobically modified water-soluble polymer has a weight average molecular weight of at least about 20,000 more preferably at least about 30,000 In certain highly preferred embodiments the water-soluble polymer hydrophobically modified has a viscosity average molecular weight of about 30,000 to about 50,000 In one embodiment of the invention the hydrophobically modified water-soluble polymer e? a hydrophobically modified cellulose ether In preferred embodiments, the cellulose ether is substantially nonionic. Preferred cellulose ethers include methylcellulose, hydroxypropylcellulose, hydroxypropylmethyl cellulose, hydroxyethylcellulose and ethyl hydroxyethylcellulose. The hydrophobic modification can be imparted to a water soluble polymer in the compositions of the present invention for example, in the form of side chains Preferably, the hydrophobic modification of the water-soluble polymer includes at least one alkyl side chain of at least about 8 carbon atoms and even more preferably at least one alkyl side chain of at least about 10 atoms carbon, so more > ~ Jfc..i preferred at least one alkyl side chain of at least about 12 carbon atoms In certain highly preferred embodiments, the hydrophobic modification of the water soluble polymer is provided by at least one alkyl side chain of at least about 14 carbon atoms, 15 carbon atoms, or 16 carbon atoms. It is generally preferred that the hydrophobic modification of the polymer include alkyl side chains of no more than about 24 carbon atoms more preferably no more than about 22 carbon atoms, still more preferably no more than about 20 carbon atoms, and most preferably no more than about 18 carbon atoms 15 In some embodiments of the compositions of the present invention the hydrophobically modified water soluble polymer is a cellulose ether having a degree of substitution of at least 2 0 In the preferred embodiments, the cellulose ether has a degree of substitution of at least about 3.0. In certain highly preferred embodiments, the cellulose ether has a degree of substitution of about 3 to about 3 6 The sizing agents useful in accordance with the invention include reactive sizing agents and non-reactive sizing agents Preferred reactive sizing agents include alkyl ketene dimers alkenyl succinic anhydrides alkenyl ketene dimers and alkyl or alkenyl ketene multimers In preferred embodiments the reactive sizing agents are liquid at room temperature and in highly preferred embodiments the reactive sizing agents are alkenyl ketene dimers. Non-reactive sizing agents include for example polymer emulsion sizing agents and turpentine resin sizing agents. Another aspect of the present invention is a substantially uniform dispersion containing a sizing agent. of paper and at least one hydrophobically-digested water-soluble polymer having a viscosity average molecular weight of about 200,000 or less. The sizing agent may be, for example, a reactive sizing agent or a non-reactive sizing agent or a combination thereof. The same De conform With the invention, preferred reactive sizing agents include alkyl ketene dimers, succinic alkenyl anhydrides, alkenyl ketene dimers, and alkyl or alkenyl ketene multimers. In preferred embodiments, the reactive sizing agents are liquid at room temperature and in SZ & s * S *, iMÍÍ highly preferred reactive sizing agents are alkenyl ketene dimers Preferred non-reactive sizing agents include for example polymer emulsion sizing agents and turpentine resin sizing agents One aspect Further of the present invention is a dispersion containing a paper sizing agent, a hydrophobically modified water-soluble polymer and a salt. Exemplary salts include the calcium, magnesium and barium halides. In preferred embodiments the salts include one or more salts selected from calcium chloride magnesium chloride magnesium bromide calcium bromide calcium nitrate magnesium nitrate calcium acetate and magnesium acetate Another aspect of the present invention is a method for treating paper that includes adding to paper at or near the sizing press a composition containing a paper sizing agent and a hydrophobic water soluble polymer modified In preferred embodiments, the composition also contains a salt. Preferred salts include calcium chloride, magnesium chloride, magnesium bromide, calcium bromide, calcium nitrate, magnesium nitrate, calcium acetate, and magnesium acetate. 'j & & j-n? ^ * j? «. »¿R. paper according to the invention the hydrophobically modified water soluble polymer preferably has a viscosity average molecular weight of about 100,000 or lessmore preferably about 50,000 or less Also preferably the viscosity average molecular weight of the hydrophobically modified water-soluble polymer is at least about 20,000, more preferably at least about 30,000. In certain highly preferred embodiments the polymer Water-soluble hydrophobically modified water has a viscosity average molecular weight of about 30,000 to about 50,000. In preferred embodiments for treating paper according to the invention, the water-soluble polymer is a cellulose ether. Preferably the cellulose ether has a degree of substitution of at least about 2 0 more preferably at least about 3 0 In certain highly preferred embodiments the cellulose ether tends a degree of substitution of about 3 5 to about 3 6 Also preferably, the hydrophobically modified cellulose ether is substantially nonionic agent Preferred nonionic hydrophobically modified water soluble polymers include methyl cellulose, hydroxypropyl cellulose, hydroxypropyl ethyl cellulose, hydroxyethyl cellulose and ethyl hydroxyethyl cellulose. In preferred embodiments for treating paper in accordance with the invention, the hydrophobic modification The water-soluble polymer is imparted by the presence in the polymer of at least one alkyl side chain of at least about 8 carbon atoms. Preferably the water-soluble polymer has at least one alkyl side chain of at least about 10 carbon atoms. carbon atoms even more preferably at least about 12 carbon atoms still more preferably at least about 14 carbon atoms In certain highly preferred embodiments, the hydrophobic modification of the water-soluble polymer includes an alkyl side chain. It is preferred, however, that the alkyl side chain has no more than about 24 carbon atoms, more preferably no more than about 22 carbon atoms, more preferably no more than about 10 carbon atoms. about 20 carbon atoms and even more preferably no more than about 18 carbon atoms. Another aspect of the present invention is a bfeügv *? ~ tjßS? iamixi *. paper containing a hydrophobically modified water-soluble polymer and a paper sizing agent. Preferably, the hydrophobically modified water soluble polymer has a viscosity average molecular weight of about 100,000 or less, more preferably at least about 30,000. In certain highly preferred embodiments, the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of about 30,000 to about 50,000. Preferably, on paper in accordance with the invention, the hydrophobically modified water-soluble polymer is a hydrophobically modified cellulose ether, and even more preferably the cellulose ether is substantially non-ionic. Preferred cellulose ethers include methyl cellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, and ethylhydroxyethylcellulose. In preferred embodiments on paper, the hydrophobic modification is imparted to the water soluble polymer by the presence in the polymer of at least one alkyl side chain of at least about 8 carbon atoms. Preferably, the water-soluble polymer has at least one alkyl side chain of at least about 10 carbon atoms, still more preferably at least about 12 carbon atoms, still more preferably at least about 14 carbon atoms In certain highly preferred embodiments, the hydrophobic modification of the water-soluble polymer includes an alkyl side chain of at least about 15 or 16 carbon atoms. It is preferred, however, that the alkyl side chain has no more than about 24 carbon atoms. of carbon, more preferably no more than about 22 carbon atoms, still more preferably no more than about 20 carbon atoms, and even more preferably no more than about 18 carbon atoms These and other aspects of the invention are will make evident to one experienced in the field in view of the following exhibition and the vindication annexed Detailed Description of the Invention It has surprisingly and unexpectedly been discovered that the uniformity and storage stability of dispersions can be improved by incorporating into the dispersions one or more polymeric materials having particular characteristics. The improvement of dispersions, in accordance with the present invention includes maintaining the substantial uniformity of a dispersion The term "substantially uniform", as used herein, means that a composition has minimal or no detectable variation in the distribution of components through the volume of the composition. For example, a substantially uniform dispersion has minimal variation in the concentration of its components over the volume of the dispersion. Preferably a substantially uniform composition has less than about 5% variation in concentration of each component through the dispersion and no variations are detected during the dispersion. visual inspection In this way, for example in certain preferred embodiments, the concentration of a particular component in a substantially uniform dispersion may vary from about 10 0% to about 10 5% at different locations within the total volume of the composition, and said variation will not be detectable during visual inspection The compositions and methods of the present invention may also improve the storage stability of dispersions. The storage stability improvement of a dispersion, for purposes of the present disclosure, includes increasing storage and / or time. of use during which the dispersion remains substantially uniform The stability improvement of a dispersion also includes increases the storage time and / or use during which no stratification is observed during visual inspection The compositions and methods of the present invention are particularly useful for improving or maintaining the uniformity of pre-mixed additives for paper that are typically stored for some time prior to application to the paper In this manner the compositions and methods of the present invention are particularly applicable to dispersions of sizing agents. The compositions of the present invention also contain defoaming pigments and optical brightening agents and the other additives useful for treating paper "Improved storage stability" as used herein means that the stratification of a dispersion during storage or use is delayed reduces or eliminates Therefore the improved storage stability can be determined by measuring the time elapsed before the stratification principle in a dispersion during storage In accordance with the use of It is expected that the compositions and methods of the present invention will not substantially detect any stratification in a dispersion during visual inspection after storage for at least about 7 days, preferably at least about 14 days. , more preferably at least about 21 days and even more preferably at least about 28 days. The absence of visibly observable stratification in dispersions will typically persist for the aforementioned periods of time at ambient temperatures such as a temperature of at least about 100%. 25SC preferably at least about 28aC more preferably at least about 30aC and still more preferably at least about 322C The period of time during which no stratification principle is observed is generally observed to increase with increased concentration of the poly Hydrophobically Modified Grouper A higher concentration limit of the hydrophobically modified polymer is determined, in part, by the effects of the polymer on certain properties of the dispersions and the importance of each property for the intended application. Specific properties affected by the polymer include viscosity and hydrophobicity. Viscosity can have a significant effect on the handling of the dispersion As a general guideline, the practical upper limit of the amount of polymer is typically reached when the hydrophobically modified polymer forms about 10 percent by weight of the solids content of the dispersion. For example, the amount of polymer can be from about 1% to about 10%, based on the total weight of the solids, more typically from about 1% to about 5%. As a percentage of the total weight of the dispersion the amount of hydrophobically modified polymer is preferably at least about 0.2%, more preferably at least about 0.4%, and even more preferably, at least about 0 5% The amount of hydrophobically modified polymer is preferably about 3% or less, more preferably about 2% or less and even more preferably about 15% or less. The practical upper limit of the amount of hydrophobically modified polymer is determined, in part by the upper acceptable limit of viscosity of the dispersion for its intended use Other factors that may affect the practical upper limit of the polymer content include the effect of increased polymer content on the properties desirable for a use ^ & Particular final document, such as paper print quality. Certain polymers having the features described herein, make them suitable for use in the compositions and methods of the present invention are known to those skilled in the art as "association agents". Association thickeners generally contain a hydrophilic structure and hydrophobic fractions that are generally present as side groups. Hydrophobic fractions can be localized, or dispersed throughout the structure. Examples of the hydrophobic moieties are long chain alkyl groups such as dodecyl, hexadecyl, and octadecyl, and alkylaryl groups such as octylphenyl and nonylphenyl. Examples of the association thicknesses are described in the U.S. Patent. No. 5 425,806, exhibitions d? which are incorporated herein by reference in their entirety. Although association thickeners have physical properties that make them useful in the compositions and methods of the present invention, it will be observed by one skilled in the art, in view of the present disclosure, that polymers provide improved uniformity and / or stability. Dispersions according to the present invention are not required to affect the viscosity properties of the dispersions The polymers useful in the methods and compositions of the present invention are hydrophobically modified water-soluble or water-dispersible polymers. By way of example, polymers useful in the compositions and methods of the present invention include hydrophobic modified polyacrylates, hydrophobically modified polyurethanes, hydrophobically modified polyethers, hydrophobically modified, or hydrophobically modified cellulosic polymeric alkali-soluble emulsions including nonionic cellulose ethers, polyether polyols, and hydrophobically modified polyacrylamides Hydrophobic modification of water soluble polymers can be imparted by the presence of hydrophobic fractions in the polymers Hydrophobic fractions are preferably alkyl groups, present as alkyl side chains in the polymer structure Preferred alkyl side chains are alkyl groups having a hydrocarbon chain of at least about 8 carbon atoms, referred to herein as C alquilo alkyl groups. More preferred are alkyl groups having at least about 12 carbon atoms in a chain, and still more preferred are alkyl groups having at least about 34 carbon atoms ^^ '^ Sr- «-" « »* ¿¿? EISÁ * ¿? *** £ hista & i'a-si ^ m ^^ * ^^ Preferably alkyl groups having approximately 24 carbon atoms or less, more preferably around 20 carbon atoms or less, still more preferably about 18 carbon atoms or less The C 15 alkyl groups and of are particularly preferred The hydrophobic fractions are preferably present in the polymers at about 1 to 3 weight percent of more preferably about 1.3 to 1 8 weight percent even more preferably about 1 4 to 1 7 weight percent, and still more preferably about 1 5 to 1 6 weight percent, based on the total weight of the polymer When the hydrophobic moiety is an alkyl group of Ct6 about 16 weight percent alkyl group based on the total weight of the polymer, it is highly preferred, preferably after said hydrophobic modification, the polymers hydrophobically The modified polymers are at least about 1% by weight soluble in water. Suitable polymers include hydrophobically modified cellulose ethers such as those described in U.S. Patent No. 4,228,277 the disclosure of which is incorporated herein by reference. Hydrophobically modified polymers preferred are cellulose ethers that are substantially nonionic. The term "non-ionic", as used herein in connection with cellulose ethers, refers to the absence of net ionic charge in the polymer repeating unit, even though it may there being present in the polymer one or more ionic groups The non-ionic character of a cellulose ether derives, in part, from the nature of substituent groups in the anhydroglucose rings of cellulose. Nonionic substituents imparting a substantially non-ionic character to a cellulosic polymer include alkyl groups, such as, for example, methyl, ethyl, hydroxyethyl and hydroxypropyl. It is preferred that the cellulose ethers for use in the present invention have a degree of nonionic substitution of at least about 2.0, more preferably at least about 3.0, with an upper limit to that degree of substitution at which solubility in polymer water is at least about 1 percent. The degree of substitution refers to the number of substituted sites in the anhydroglucose ring. This nonionic substitution is preferably in the form of a group selected from methyl, hydroxyethyl and hydroxypropyl. Preferably the degree of non-ionic substitution, such as substitution. of hydroxyethyl, is from about 3.5 to 3.6. Hydrophobically modified hydroxy alkyl cellulose polymers, such as hydrophobically modified methyl cellulose, hydrophobically modified hydroxypropyl cellulose, hydrophobically modified hydroxypropylmethyl cellulose, hydrophobically modified hydroxyethyl cellulose, and hydrophobically modified ethyl hydroxyethyl cellulose, and others described in the Patent of E UA No. 4,228,277, are highly preferred, with hydrophobically modified hydroxy ethyl cellulose being particularly preferred. Preferably, hydrophobic water-soluble polymers modified for use in the present invention have viscosity average molecular weight of about 200,000 or less, more preferably about 100,000 or less, more preferably about 50,000 or less Soluble polymers in hydrophobically modified water preferably have a viscosity average molecular weight of at least about 20,000, more preferably at least about 30,000. In certain highly preferred embodiments, the hydrophobically modified water soluble polymers have a viscosity average molecular weight of about 30,000 to approximately 50,000. The amount of polymer required to achieve the desired improvement in uniformity, as indicated by the reduction of stratification or delay of stratification principle, in dispersions prepared according to the present invention, is determined in part by the composition of the dispersion. Typically, in a dispersion containing about 30% solids, of which about 12% solids are due to the sizing agent and about 18% are due to the salt, the amount of the hydrophobically modified polymer in the dispersion is at least about 0.3 weight percent. Preferably, the amount of polymer is at least about 0.5 weight percent, and more preferably at least about 0.7 weight percent. Also preferably, the amount of polymer is about 2.0 weight percent. less, more preferably, about 1 5 percent or less, still more preferably about 1.3 weight percent or less. In certain highly preferred embodiments, the amount of polymer is from about 0.7 to about 1.3 weight percent. The methods of the present invention are useful for forming dispersions of a wide variety of materials in aqueous media. The methods of the present invention They are particularly useful for forming dispersions of agents useful in treating cellulose fibers. These agents include those useful in treating textiles, carpet fibers, and "Paper" paper, as used herein, including sheets or webs of fibrous materials consisting primarily of of cellulose fibers These sheets or webs can be relatively thin, or they can be thicker cardboard-like materials such as cardboard, cards, and the like. The cellulose fibers from which the paper is made can be from a variety of sources including softwoods, hardwoods, papyrus, linen, jute and others. Even though they may also be present As synthetic fibers, for purposes of the present invention, the paper to be treated with dispersion agents are preferably substantially totally made from non-synthetic cellulosic fibers. In particular, the methods and compositions of the present invention are useful for dispersions containing dispersing agents. Sizing Dispersions containing sizing agents, for concomitant use with the present invention, preferably contain at least about 5% of one or more sizing agents, more preferably at least about 3%, and even more preferably at least approximately 10%. The maximum amount of sizing agent is preferably about 20% or less, more preferably about 15% or less. All amounts expressed as percentages in this exposure are by weight based on the total weight of the solution mixture or paper composition. is appropriate unless noted otherwise. Different types of sizing agents can be used for paper determined in part by the conditions under which the paper is made. In this way, the compositions used to treat paper may contain sizing agents. non-reactive including dispersed rosin resin sizing agents, reactive sizing agents and combinations or blends of sizing agents For the manufacture of paper made or alkaline pH manufacturing conditions, the sizing agents based on alkyl ketene dimers ( AKDs), alkenyl succinic anhydride (ASA) sizing agents and sizing agents based on alkyl dimers enyl ketene or multimers are preferred The appropriate reactive and non-reactive sizing agents are known to those skilled in the art and are described in U.S. Patent Application Serial No. 09 / 126,643, the teachings of which are incorporated herein by reference in their entirety. Examples of non-reactive sizing agents include polyimatic sizing agents such as for example BASOPLAST (R) 335D non-reactive polymer surface sizing emulsion from BASF Corporation (Mt Olive NJ), FLEXBOND (R) 325 emulsion of a vinyl acetate-butyl-plate copolymer from Air Products and Chemicals Inc. (Trexlerto n PA) and non-reactive sizing agents PENTAPRINT (R) from Hercules Incorporated (Wilmington DE) Reactive sizing agents include cetane dimers and multimers that are liquid at room temperature such as alkenyl ketene dimers and multimers Reactive sizing agents have a reactive functional group that is capable of covalently binding to cellulose fiber in paper and the hydrotoxic tails that tend to be oriented away from the fiber imparting water repellency to the fiber In the compositions and methods of the present invention the reactive sizing agents are preferably in liquid form ie the compositions of the present invention may comprise liquid reactive sizing agents within a dispersion Ketene dimers are well known for use as paper sizing agents AKDs, containing a beta-lactone ring are typically prepared by the dimerization of alkyl ketenes made from two fatty acid chlorides Commercially available alkyl ketene dimer sizing agents prepared from palmitic and / or stearic fatty acids include vg sizing agents Hercon1"1 and Aquapel (R (both of Hercules Incorporated, Wilmington, DE) AKD sizing agents and their use are described, for example, in US Patent 4 017,431, the teachings of which are hereby incorporated by reference in its entirety The uses of paper made under alkaline conditions are described in U.S. Patent No. 5,766,417 whose disclosure is hereby incorporated by reference in its entirety. Commercially available alkenyl ketene dimer sizing agents include v. Prec? s (R) sizing (Hercules Incorporated Wilmington DE) Similarly, ketene multimers containing more than one ring of bet a-lactone can be used as paper sizing agents. The ketene multimers prepared from a mixture of mono and dicarboxylic acids are described as sizing agents for paper in U.S. Patent No. 5,725,731. USA Series Nos 08/601 113 and 08 / 996,855; and PCT Patent Application No. 96/12172, the exposures of each of which are hereby incorporated by reference in their entirety. The alkyl ketene dimer and multimer mixtures as capture agents for use in reprographic machines and of high speed conversion are described in the European Patent Application Publication Nc. 0 629 741 The described alkyl ketene multimers are made from the reaction of a molar excess of monocarboxylic acid, typically a fatty acid, with a dicarboxylic acid, and are solid at 25 ° C. Other alkali sizing agents are described in the U.S. Patent. 5,685,815, the exposures of which are hereby incorporated by reference in their entirety. Paper typically made under acidic papermaking conditions, referred to as acidic paper, is usually prepared with well-known rosin-based sizing agents (also referred to in US Pat. present as "dispersed rosin resin sizing agents"), which are non-reactive sizing agents. Some papers made under neutral and alkaline papermaking conditions can be prepared with dispersed rosin resin sizing agents. Dispersed turpentine rosin sizing agents are well known to those experienced in the papermaking industry. Turpentine resins useful as dispersed turpentine ream sizing agents include unstrengthened turmeric ream, strengthened turmeric ream and ream. extended turpentine, as well as turpentine esters and mixtures and combinations thereof In this manner the term "turpentine resin" is used herein to include all forms of res a de turpentine dispersed useful in a sizing agent Suitable turpentine sizing agents include those described in US Patents 3,966,654 and 4,263,182, the exposures of which are hereby incorporated by reference in their entirety Fortified turpentine resins include reaction products of an adduct of turpentine and an acidic compound containing a carbonyl group at fa, Beta-Unsaturated Methods for preparing strengthened turpentine ream are well known to those experienced in the art and are described, for example, in U.S. Patents 2,628,918 and 2,684,300 U.S. Patent Application No. 09 / 046,019, and Patent Application. of PCT No. 97/01274 the teachings of each of which are hereby incorporated by reference in their entirety. Other appropriate turpentine stocks that can be used in the methods of the present invention include turmeric ream esters. Suitable turpentine esters include those described in U.S. Patents 4 540 635 and 5,201,944 the exposures of which are incorporated herein by reference. Turpentine ream sizing agents may be extended if desired by spreaders for the such as waxes (particularly paraffin wax and microcrystalline wax) hydrocarbon resins including those hydrides petroleum hydrocarbons and terpenes, and the like Hydrophobic acid anhydrides useful as paper sizing agents include those described for example in U.S. Patent 3,582,464 the disclosure of which is incorporated herein by reference in its entirety Other Agents d? Suitable paper sizes include hydrophobic organic isocyanates, such as, for example, alkylated isocyanates, alkylcarbonyl chlorides, alkylated methalamines such as coated melamines and styrene acrylates. If desired, combinations of paper sizing agents can be used. salts useful in forming dispersions of iawt »jgtt2te, to sizing agents include divalent metal salts that are soluble in aqueous medium in amounts typically used in an aqueous sizing medium. The appropriate metal salts are preferably soluble in aqueous medium having a pH of about 7 to about 9. , which includes the pH of the aqueous sizing medium generally used in the sizing press. Example metal salts include calcium magnesium, barium halides and the like. Preferred metal salts are mineral or organic acid salts of divalent cationic metal ions. suitable divalent metal salts such as calcium chloride magnesium chloride magnesium bromide calcium bromide barium chloride calcium nitrate magnesium nitrate calcium acetate and magnesium acetate Calcium and magnesium chlorides are preferred The use of divalent metal salts when forming dispersions of paper sizing agents is described in the Patent Application of USA No. 09/126 643 already incorporated herein by reference. The methods of preparation of dispersions of sizing agents, compatibility of additives and other conditions and equipment can be selected in accordance with the conventional practices of those experienced in the field in view of the compatibility and performance requirements for a particular application As will be recognized by those skilled in the art, mixtures that produce coagulation and / or precipitation that may interfere with the production of paper are generally not appropriate. The use of additives known to those skilled in the range for improving inkjet printing is within the scope of the present invention. Additives that may optionally be present in the dispersions include polyvinyl alcohol, polyvinylpyrrolidone and polyethyleneimine. Surface treatment additives may be used operationally including latex emulsions. convection Internationally used as paper additives The amount of additives in the sizing composition can be, for example, from about 0.01% to about 3%, and varies with the type of additive and the amount of solution collected by the paper during the treatment Sizing Press In accordance with the invention, the dispersions can be prepared generally using methods known to those skilled in the art. However, it is preferred that all components of the dispersion, except the hydrophobically modified polymers of the invention, be combined before that a hydrophobically modified polymer be added. It is also preferred that a solution of the hydrophobically modified polymer is made, and the solution is then added to the other components of the dispersion. This solution can be made in any suitable aqueous medium, such as, for example, water or a diluted aqueous salt solution such as dilute calcium chloride solution. The addition of the solution to the remaining combined components of the dispersion is preferably achieved with stirring. Compositions of the present invention containing sizing agents, including the sizing agents described herein, are useful in treating cellulose fibers and substrates containing cellulose fibers. Examples of substrates for which the compositions of the present invention, including those containing sizing agents, are useful, include paper; wood, wood chips, cardboard, non-woven fibers containing cellulose fibers, and substrates containing processed cellulose such as fiber board. The paper sizing compositions containing compositions of this invention can be applied to the surface of the paper or other substrate by any of several different conventional means, well known in the papermaking branch. Alternatively, sizing agents can be applied as internal sizing agents and added to the paper pulp suspension prior to sheeting. In surface sizing treatments, a sizing composition is generally applied to a surface treatment on both sides of the paper being treated, but yes. If desired, the surface application could be made to only one side of the sheet of paper. A preferred application method uses a conventional sized or unmeasured size press in a conventional papermaking process. When this technique is used, the application temperature is at least about 50nC and not more than about 80B, typically about 60SC, and the composition comprising a sizing agent is applied on or near the sizing press. However, the invention is not limited to the treatment of paper or other substrate through the sizing press treatment or at the temperature typically used in the sizing press, since the substrate can also be treated with the composition by other known methods. the experts in the field. Various modifications of the invention, in addition ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ of those described herein, will be apparent to those skilled in the art from the foregoing description. These modifications are intended to be within the scope of the appended claims. The statements of each patent, patent application, and publication cited or described in this document are hereby incorporated by reference in their entirety.

EXAMPLES The following examples are only illustrative of the present invention and should not be construed as limiting the scope of the invention in any way. These examples and equivalents thereof will become more apparent to those skilled in the art in the light of the present disclosure and the accompanying claims. All percentages used in the following examples are by weight unless noted otherwise. In the Examples described below, when paper was tested, the paper was passed through a laboratory puddle size press and the desired treatment was applied. The treated paper was then immediately dried in a drum dryer. The paper was conditioned during a minimum of 24 hours before the inkjet test. In all the examples below the ink jet printing was conducted with the Hev / lett-Packard DeskJet 660C inkjet printer. The print settings were made on the "best" paper and "plain paper" within the Hewlett software. -Packard that was supplied with the printer. The printing characteristics of the paper were measured at least 1 hour after printing. Optical density readings were made with Cosar densitometer model 202. The printing characteristics were evaluated using a test pattern with solid color areas, black text printing. , and areas printed in black on yellow and yellow on black. An evaluation method is described in the Hewlett-Packard test criteria. The classifications listed on a good, regular and low scale are based on the Hewlett-Packard classifications of good, acceptable and unacceptable. See, v.gr, Hewlett Parckard Paper Acceptance Criteria for HP Deek Jet 500C, 550C and 560C Printers Hewlett-Packard Company, July 1, 1994. In some examples, paper sizing was measured by the Hercules Sizing Test ( HST) & s &S & amp; tt £ MÉi »§ | MMÉ '• S The Hercules Sizing Test is a well-recognized test for measuring sizing performance and is described in TAPPI Standard T530, the exposures of which are hereby incorporated by reference in their entirety. A higher HST number is considered to represent better sizing capacity (less water penetration). The starch solutions were prepared by cooking the starch in water at about 95 ° C for 30 to 60 minutes, and then adjusting the pH to about 8. The components noted in the Examples were mixed into the starch. The mixtures were stirred and the pH was adjusted as noted in the Examples below. Within about 10 minutes of adding the materials to the starch mixtures, the mixtures were applied to the paper prepared as described above. The base weight of the paper used in all cases around that paper normal copy, or 75 g / m2 Example 1 A 46 2 g of Hercules Precis 2000 sizing agent (P 2000, 26% solids), 23.4 of Dow Flake calcium chloride dihydrate (77% solids) were slowly added from Dow Chemical, with stirring. A 4% solution of hydrophobically modified hydroxyl ethyl cellulose was prepared by slowly adding the polymer to water and stirring for 2 hours Hydrophobically modified hydroxy ethyl cellulose had a viscosity average molecular weight of 30,000-50,000 a degree of substitution of hydroxy ethyl of 3 5-3 6 and 1 65 weight percent of C16 side chains The solution is then I let sit for about 1 day and then stirred to further bring the polymer into the solution. Calcium chloride / P2000 mixture hydrophobically modified hydroxy ethyl cellulose solution and water were combined in separate glass jars of 118 28 milliliters in the relationships listed in Table 2 The height of the combined solution in each jar was 53 mm Solution jars were placed in a 329C bath for 4 weeks The solutions were visually examined for stratification several times during the four weeks The stratification was quantified by measuring the height of the clear area at the bottom of each jar Results are recorded in Table 3 Table 2 Solutions used in Example 1 Sample Mixture of CaC12 / P200 Polymer solution water (g) (g) of cellulose (g) ) A 69 6 0 30 4 B 69 6 26 3 4 1 C 69 6 30 0 0 4 Table 3 Stratification of Solutions as Indicated by Height of the Clear Area in the Bottom of the Jar Sample 7 days 14 days 21 days 28 days A.! 1 4 5 B 0 0 < 1 < 1 COO 0 0 The results indicate that the addition of the modified hydroxy ethyl cellulose slowed down the stratification regime of the solutions At a level of 1 2% polymer in the samples (sample C) there was essentially no stratification after 4 weeks at 32fiC Example 2 (Comparative Example) In this example, polymers that were not hydrophobically modified were added to sizing agent solutions, and stratification A was measured to a mixture of 30% solids (18% solids due to CaC12 and 12% solids). solids due to sizing agent P2000), the materials listed in Table 4 were added using the procedure of Example 1 The way in which the materials were added and the aggregate amount are listed in Table 4 100 g samples of each mixture each was placed in a glass jar of 118 28 milliliters The height of the samples in each jar was 53 mm The jars were placed in a 32 ° C bath for 4 weeks The samples were visually examined for stratification over a period of four weeks The height of the clear area at the bottom of the jars was measured to determine the principle of stratification. The results are recorded in Table 5 TABLE 4 Additives used in Example 2 Sample Additive additive form% additive in the final mixture 2A-0 2B CMHEC 1% solution 0 025 2C HMHEC 1% solution 0 125 2D HMHEC 1% solution 0 50 2E PVA 3% solution 0 50 CMHEC = carboxy methyl hydroxy ethyl cellulose CMHEC 420H from Hercules Inc. HMHEC = Natrosol Plus 330 hydroxy methyl hydroxy ethyl cellulose from Hercules Inc. PVA = Airvol 540S polyvinyl alcohol from Air Products.

TABLE 5 (Example 2) Stratification as indicated by the Area Height Clara in the Jar Fund Stratification (mm) after the number of Sample days indicated in bath at 32SC 5-11-13 19-21 23 43-48 2A 0 3 9 2B 2 17 2C 4 6 2D 6 2E 5 11 The results show that none of the polymeric additives listed in Table 4 significantly delayed the stratification principle of the solutions, and that with CMHEC and polyvinyl alcohol, it was observed an increase in stratification.

Example 3 A solution of 3% hydroxyl ethyl cellulose having a viscosity average molecular weight of 30,000-50,000, a degree of hydroxy ethyl substitution of 3 5-3 6 and 16 weight percent of Cl6 side chains was prepared by slowly adding the polymer to water and stirring for 2 hours The solution was allowed to settle for about 1 day Calcium chloride dihydrate and water were added to form solutions as in Example 1 Four separate samples were prepared by adding P2000 sizing agent in The quantities specified in Table 6 Samples were each placed in a glass jar of 118 28 milliliters The height of the sample in each jar was 53 mm The samples were placed in a bath at 32aC for 4 weeks, and examined visually for stratification at various times during the four weeks The height of the clear area at the bottom of the jars was measured to determine the stratification. s are shown in Table 7 TABLE 6 ESTER CaCl 2) HMP agent water polymer: final tg) (g) (g) size P2000% solids A 23 9 0 30 0 46 2 0 B 23 9 16 7 13 3 46 2 0 5 C 23 9 23 3 6 7 46 2 0 7 D 23 9 30 0 0 46 2 0 9 TABLE 7 Stratification as indicated by the Area Height Clara in the Jar Background Stratification after the indicated number of days in the bathroom Show 2 days 14 days 21 d: The 2S days A 1-2 4 4 6 B 1 2 3 4 C < 1 2 3 3 D 0 < 1 < 1 3 The results indicate that the addition of hydrophobically modified cellulose polymer slowed the stratification, and the amount of stratification was reduced with increasing amounts of polymer.

EXAMPLE 4 This example illustrates the effect of increasing the amount of hydrophobically modified cellulose polymer on the stratification of a 20% solids dispersion of sizing agent. A solution of 3% polymer was prepared as in Example 3, the solution was of or rest for about 1 day. Calcium chloride dihydrate and P2000 sizing agent were added in the amounts ri. ^^ specified in Table 8 The resulting sample solutions were each placed in a glass jar of 118 28 milliliters The height of the samples in each jar was 53 mm The jars were placed in a bath at 32aC for 4 hours. weeks and visually examined for stratification during the four weeks The height of the clear area of the bottom of the jars was measured The results are recorded in Table 9 TABLE 8 Solutions Used in Example 4 Sample CaCl2 * HMP1 Water P2000 Final 2H20 solution (g) HMP% 2 A 15 9 0 53 3 30 8 0 B 15 9 11 1 42 2 30 8 U 33 C 15 9 20 0 33 3 30 8 0 60 D 15 44 4 8 9 30 8 1 33 E 15 9 53 3 0 30 8 1 60 1 HMP polymer hydrophobically modified 2 amount of polymer as weight percent of a dispersion of 20% solids based on the total weight of the dispersion HE? ~ .AÍ¡ £.

TABLE 9 Stratification as Indicated by the Height in mm of Clear Area in the Bottom of the Jar Sample 7 days 14 days 21 days 28 days A 1-2 4 4 6 B 2 4 4 5 C < 1 2 2 4 D 0 < 1 < 1 < 1 The results indicate that increasing the amount of polymer in the dispersion decelerates the stratification.

Example 5 The dispersions prepared in Example 1 were used to treat paper as described above and as set forth in U.S. Patent Application, A. No. 09 / 126,643. Each dispersion was treated with two levels of dry surface additive; 1.36 kilograms (kg) and 2.27 kilograms of additive (P2000 + CaCl2 + HMP) per ton of paper in its dry, final state. Starch was used as a carrier for the surface additives. Sizing was evaluated with the conventional Hercules Stencil Test (HST) in the same manner as described in the U.S. Patent Application. No. 09 / 126,643. The higher HST number indicates better sizing (less water penetration). The treated base coat was treated with internal sizing with a Hercules dispersed turpentine resin sizing agent. The resulting sizing data are listed in Table 10 TABLE 10 Effect of cellulose polymer on surface size of an acid-based sheet SAMPLE (The designations HST (seconds refer to Example 1 Starch only 38 1.36kg / ton sample A 2.27kg / ton sample A 135 1.36kg / sample ton B 76 2.27kg / ton of sample B 129 1.36kg / ton of sample C 188 2.27kg / ton of sample C 196 The data show that the addition of 1% hydrophobically modified cellulose polymer had no detectable effect on the sizing on the acid-based sheet The addition of 1.2% hydrophobically modified cellulose polymer (sample C) significantly improved sizing.

TABLE 12 Effect of cellulose polymer on black ink-jet printing of an alkaline base sheet SAMPLE Black Black Black (See Example 1) OD Growth Hardness of Line Border Starch only 1.50 fg * fg 1. 36kg / ton sample A 1.68 g g 2.27kg / ton sample A 1.69 g g 1.36kg / ton sample B 1 68 g g 2.27kg / ton sample B 1.69 g g 1.36kg / ton sample C 1 65 g f-g 2. 27kg / ton sample C 1 67 g g * "f" indicates print quality "regular", "g" indicates "good" print quality TABLE 13 Effect of cellulose polymer in black ink-jet printing of an alkaline base sheet Sample Black / Yellow Black / Yellow (See Example 1) Starch Line Border Hardness Growth only ff 1.36kg / ton sample A g fg 2.27kg / ton sample A g fg 1.36kg / ton sample B fg fg 2.27kg / ton sample B g fg 1.36kg / ton sample C g fg 2.27kg / ton sample C fg f As indicated in Example 1, the amount of hydrophobically modified polymer in sample C is greater than that in sample B, and sample A does not contain hydrophobically modified polymer. The results in Table 11 indicate that the sizing efficiency decreases slightly as the hydrophobically modified polymer content increases, and the decrease is more apparent at the surface treatment level of 2.27kg / ton. In this way, the results show the appropriateness of the hydrophobically modified polymer limit for a given application may depend on its effect on other desirable properties. The results also indicate that the surface treatments improved the quality of inkjet printing compared to the use of starch alone, with the exception of the effect of 2.72kg / ton of sample C on the black / yellow edge hardness. Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. These modifications are intended to be within the scope of the appended claims.

Claims (2)

1. CLAIMS 1 - . 1 - A paper sizing composition comprising a paper sizing agent and at least one hydrophobically modified water soluble polymer having a viscosity average molecular weight of about 200,000 or less.
2. 2. The composition according to claim 1, wherein the hydrophobically modified water soluble polymer has a viscosity average molecular weight of about 100,000 or less. 3 - The composition according to claim 1, wherein the polymer solves in hydrophobically modified water has a viscosity average molecular weight of about 50,000 or less. 4. The composition according to claim 1, wherein the hydrophobically modified water soluble polymer has a viscosity average molecular weight of at least about 20,000. The composition according to claim 1, wherein the soluble polymer in hydrophobically modified water it has a viscosity average molecular weight of at least about 30,000. 6. The composition according to claim 4, wherein the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of from about 30,000 to about 50,000. 7. The composition according to claim 1, wherein the hydrophobically modified water soluble polymer is hydrophobically modified cellulose ether. 8. The composition according to claim 7, wherein the cellulose ether is substantially non-ionic. 9. The composition according to claim 7, wherein the cellulose ether is selected from the group consisting of methyl cellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose and ethylhydroxyethylcellulose. 10. The composition according to claim 8, wherein the cellulose ether is hydroxy ethyl cellulose. 11. The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one side chain. of alkyl of at least about 8 carbon atoms. 12. The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 10 carbon atoms. 13. The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 12 carbon atoms, 14. The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain and at least about 14 carbon atoms. 15. The composition according to claim 1, wherein the hydrophobic modification of the soluble polymer in The water comprises at least one alkyl side chain of at least about 15 carbon atoms. 16. The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least 15 carbon atoms. or 16 carbon atoms. 17 -. 17 - The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 24 carbon atoms. 18 - The composition according to claim 1, wherein the hydrophobic modification of the water soluble polymer comprises at least one alkyl side chain of not more than about 22 carbon atoms 19. The composition according to claim 1, wherein the hydrophobic modification of the water soluble polymer comprises at least one alkyl side chain of no more than about 20 carbon atoms. 20 - The composition according to claim 1, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 18 carbon atoms. 21. The composition according to claim 7, wherein the cellulose ether has a degree of substitution of at least about 2 0. 22. The composition according to claim 7, wherein the cellulose ether has a degree of substitution of at least about 3.0. 23. The composition according to claim 7, wherein the cellulose ether has a degree of substitution of about 3.5 to about 3.6, 24. The composition according to claim 1, wherein the composition is in the form of a substantially uniform dispersion. 25. The composition according to claim 1, wherein the sizing agent comprises a reactive sizing agent. 26. The composition according to claim 1, wherein the reactive sizing agent is selected from the group consisting of alkyl ketene dimers, succinic alkenyl anhydrides, alkenyl ketene dimers and alkenyl ketene multimers. 27. The composition according to claim 1, wherein the sizing agent is a liquid. 28. The composition according to claim 25, wherein the reactive sizing agent comprises an alkenyl ketene dimer, 29. The composition according to claim 1, wherein the sizing agent comprises a non-reactive sizing agent. . 30. The composition according to claim 1, comprising at least one reactive sizing agent and at least one non-reactive sizing agent. 31. The composition according to claim 29, wherein the sizing agent is selected from the group consisting of polymer emulsion sizing agents and turpentine resin sizing agents. 32, - The composition according to claim 1, further comprising a salt 33. The composition according to claim 32, wherein the salt is selected from the group consisting of calcium, magnesium and barium halides. 34. The composition according to claim 33, wherein the salt is selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide, calcium bromide, calcium nitrate, magnesium nitrate, acetate of calcium, and magnesium acetate. 35.- A method for treating paper comprising adding to the paper on or near a sizing press the composition according to claim 1. The method according to claim 35, wherein the water soluble polymer hydrophobically modified. it has a viscosity average molecular weight of about 100,000 or less. The method according to claim 35, wherein the hydrophobically modified water soluble polymer has a viscosity average molecular weight of at least about 50,000 or less. - The method according to claim 35, wherein the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of at least about 20,000. The method according to claim 35, wherein the water-soluble polymer hydrophobically modified has a viscosity average molecular weight of at least about 3 0.000 40.- The method according to claim 35, wherein the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of at least about 30,000 to about 50,000. The method according to claim 35 wherein the hydrophobically modified water soluble polymer is a hydrophobically modified cellulose ether 42 - The method according to claim 41 wherein the hydrophobically modified cellulose ether is substantially nonionic 43 - The method according to claim 41 wherein the ether of cellulose is selected from the group consisting of methylcellulose, hydroxypropylcellulose, hydroxypropylmethyl cellulose hydroxyethylceulose and ethylhydroxyethycellulose 44 - The method according to claim 41, wherein the cellulose ether is hydroxy ethyl cellulose 45 - The method according to claim 35, wherein the hydrophobic modification of the soluble polymer Water comprises at least one alkyl side chain of at least about 8 carbon atoms. The method according to claim 35 wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least approximately 10 carbon atoms. 47. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 12 carbon atoms. 48. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 14 carbon atoms. 49. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 15 carbon atoms. 50.- The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of 15 or 16 carbon atoms. 51. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 24 carbon atoms. ^ &s £ gSSr * 52.- The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 22 carbon atoms. 53. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 20 carbon atoms. The method according to claim 35, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of not more than about 18 carbon atoms. The method according to claim 41, wherein the cellulose ether has a degree of substitution of when less approximately 2.0. 56. The method according to claim 41, wherein the cellulose ether has a degree of substitution of at least about 3.0. 57 - The method according to claim 41, wherein the cellulose ether has a degree of substitution of about 3.5 to about 3.6. 58.- A paper comprising the composition according to claim 1. 59.- The paper according to claim 58, wherein the hydrophobically modified water soluble polymer has a viscosity average molecular weight of about 100,000 or less. 60.- The paper according to claim 58, wherein the hydrophobically modified water soluble polymer has a viscosity average molecular weight of about 50,000 or less. - The paper according to claim 58, wherein the soluble polymer in hydrophobically modified water it has a viscosity average molecular weight of at least about 20,000. 62. The paper according to claim 58, wherein the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of at least about 30,000. 63. The paper according to claim 62, wherein the hydrophobically modified water-soluble polymer has a viscosity average molecular weight of about 30,000 to about 50,000. 64. The paper according to claim 58, wherein the hydrophobically modified water-soluble polymer is a hydrophobically modified cellulose ether. The paper according to claim 64, wherein the cellulose ether is substantially non-ionic. 66. The paper according to claim 64, wherein the cellulose ether is selected from the group consisting of methyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose, and ethyl hydroxyethyl cellulose. 67, - The paper according to claim 66, wherein the cellulose ether is hydroxy ethyl cellulose. 68.- The paper according to claim 58, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 8 carbon atoms. 69.- The paper according to claim 58, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 10 carbon atoms. 70. The paper according to claim 58, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 12 carbon atoms. 71. The paper according to claim 58, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 14 carbon atoms. 72. The paper, according to claim 58, wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of at least about 15 carbon atoms. 73.- The paper according to claim 58, wherein the hydrophobic modification of the water soluble polymer comprises at least one alkyl side chain of 15 or 16 carbon atoms, 74.- The paper according to claim 58, where the hydrophobic modification ^^ ^ s & ^ ^^^^^^? of the water-soluble polymer comprises at least one alkyl side chain of not more than about 24 carbon atoms 75 - The paper according to claim 58 wherein the hydrophobic modification of the water-soluble polymer comprises at least one alkyl side chain of no more than about 22 carbon atoms 76 - The paper according to claim 58 wherein the hydrophobic modification of the water soluble polymer comprises at least one alkyl side chain of no more than about 20 carbon atoms 77 - The paper according to claim 58 wherein the hydrophobic modification of the water soluble polymer comprises at least one alkyl side chain of not more than about 18 carbon atoms 78 - The paper according to claim 64, wherein the cellulose ether has a degree of substitution of at least approximately 2 0 79 - The role of conf The composition according to claim 64 wherein the cellulose ether has a degree of substitution of at least about 2 0. 80 - The paper according to claim 64, wherein the cellulose ether has a degree of substitution of about 3 5. to about 3 6 81 - The paper according to claim 58, wherein the sizing agent comprises a reactive sizing agent 82 - The paper according to claim 58, wherein the reactive sizing agent ST selects from the group consisting of alkylketene dimers succinic alkenyl anhydrides, alkenyl ketene dimers and alkenyl ketene multimers 83 - The paper according to claim 81, wherein the reactive sizing agent comprises an alkenyl ketene dimer 84 - The paper of according to claim 58, wherein the sizing agent is a liquid 85 - The paper according to claim 58, wherein the Sizing agent comprises a non-reactive sizing agent 86 - The paper according to claim 85, wherein the sizing agent is iS ^? aB ^? »^ a? Ju i selects from the group consisting of polymer emulsion sizing agents and turpentine resin sizing agents 87. The paper according to claim 58, wherein the sizing agent comprises at least one reactive sizing agent and at least one non-reactive sizing agent ^^^^^^ s ^^^ ^ ^