CN1408039A - Method for using hydrophobically associative polymers in preparing cellulosic fiber compositions, and cellulosic fiber compositions incorporating the hydrophobically associative polymers - Google Patents

Abstract

A papermaking method and a composition which utilize, as a drainage aid, a water soluble hydrophobically associative polymer which is a copolymer prepared from monomers which include a hydrophobic ethylenically unsaturated monomer, and one or more of a nonionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, and an anionic ethylenically unsaturated monomer.

Description

Methods of using hydrophobically associating polymers in the preparation of cellulosic fiber compositions, and cellulosic fiber compositions comprising hydrophobically associating polymers

Background of the invention

1. Field of invention

The present invention relates to the use of hydrophobically modified water-soluble polymers, also known as hydrophobically associated polymers or HAPs, in the preparation of cellulosic fiber compositions. The invention also relates to cellulosic fiber compositions, such as paper or board, which include HAPs.

2. Description of background and other information

The production of cellulosic fiber sheets - especially paper and board - involves the following steps:

- the aqueous slurry for the production of cellulose fibres, which can also be used as dietary inorganic extenders or pigments;

- depositing the slurry onto a moving wire or fabric; and

- Forming a sheet from the solids content of the slurry by water filtration.

The sheet is then pressed and dried to further remove moisture. Organic and inorganic chemicals are often added to the slurry prior to the sheet forming step to make the papermaking process cheaper or faster, or to achieve special properties in the final paper product.

There are constant efforts in the paper industry to improve paper quality, increase productivity, and reduce manufacturing costs. Chemicals are often added to the fiber slurry before it reaches the papermaker's wire or fabric to improve the drainage/dewatering and solids retention of the process; these chemicals are known as drainage and/or retention aids.

With regard to drainage/dewatering improvements, drainage or dewatering of fiber slurries on papermaking wires or fabrics is often the limiting step in achieving faster papermaking processes. Improved dewatering can also result in a drier sheet in the press and dryer section, reducing steam consumption. Additionally, this step is the stage in the papermaking process that determines the final properties of many paper sheets.

With regard to solids retention, papermaking retention aids are used to increase the retention of fine furnish solids in the web during drainage and turbulent flow processes to form the web. Without proper retention of fine solids, they will be lost to the process effluent or accumulate to high levels in the recirculating white water cycle, possibly causing deposit buildup and compromising the drainage of the paper machine. Additionally, insufficient retention of fine solids will increase papermaking costs due to the loss of additives intended to be absorbed onto the fibers to provide corresponding paper opacity, strength, or sizing properties.

High MW water-soluble polymers with cationic or anionic charges have traditionally been used as retention and drainage aids. Recently developed inorganic microspheres known as retention and drainage aids, when combined with high MW water soluble polymers, have shown excellent retention compared to conventional high MW water soluble polymers. and water filtration performance. US 4,294,885 and 4,388,150 teach the use of starch polymers with colloidal silicon dioxide. US 4,753,710 teaches flocculation of pulp furnish using a high MW cationic flocculant comprising shearing the flocculated furnish and then adding bentonite to the furnish. US 5,274,055 and 5,167,766 disclose the use of chemically crosslinked organic microparticles or micropolymers as retention and drainage aids in papermaking processes.

Hydrophobically modified, water-soluble polymers, hereinafter also referred to as Hydrophobically Associating Polymers or HAPs, are known in the art, see for example: the Encyclopedia of PolymerScience and Engineering, 2nd Edition, 17, 772- 779. US4,432,881 and 4,861,499 disclose the use of these polymers as thickeners for coating formulations and oil recovery methods such as drilling mud formulations, fracturing fluids, fluid flow control agents, friction reducers, pressure transmission fluids, and lubricants the use of. These patents do not teach or suggest the use of the polymers in cellulosic compositions, such as paper, or in processes for making these cellulosic compositions.

US 4,305,860 discloses the preparation of stable, pumpable, solvent-free polyampholyte lattices (colloidal dispersions of solid copolymers in water), characterized by their colloidal nature, their high solids content and low bulk viscosity. In the presence of water and free radical initiators and optional chelating agents, by making about 10-30 mole % of at least one cationic monomer, 5-30 mole % of at least one anionic monomer, 15-35 The crystal lattice is prepared by polymerizing mole percent of at least one hydrophobic monomer and 5-70 mole percent of at least one nonionic hydrophilic monomer, wherein the total percentage of monomers is 100 mole percent. The lattices are said to be particularly useful as pigment retention and drainage aids in the manufacture of paper and can be added to pulp in the headbox, beater, hydropulper or stock chest middle. A high content of hydrophobic groups (>15 mole %) renders the disclosed polymers insoluble in aqueous solutions, which in itself would distinguish it from the HAP polymers disclosed in this invention.

EP 0 896 966 A1 discloses the preparation of associative polymers by the phase inversion emulsion method using hydrophobic side chains of acrylic acid extended by polyoxyethylene groups. The associative acrylic polymer comprises: 95-99.95% mole of at least one monomer selected from neutral ethylene, anion or cationic monomers, 0.05-5% mole of at least one monomer containing 2,4,6- an acrylic monomer with a triphenylethylphenyl group, and 0-0.2 mole percent of at least one polyunsaturated monomer. Preferably, the associative polymer comprises 0.5-5 mole percent polyoxyethylene 2,4,6-tristyrylbenzylacrylate. The polymers can be used in various fields, such as for coatings, glues and adhesives, construction, textiles and paper. The compositions described can be used as thickeners, flocculants, and/or charge retention agents; no data or further instructions are provided regarding their use.

Summary of the invention

The present invention relates to a cellulosic fiber composition, in particular to cellulosic sheets, such as paper or board. In addition, the present invention also relates to a method for the preparation of said composition.

The invention relates to a method for preparing a cellulose fiber composition, comprising adding HAP to a cellulose slurry, and the invention also relates to a cellulose fiber composition comprising an aqueous cellulose pulp slurry and HAP. HAP preferably: includes hydrophobic groups capable of forming a physical network through hydrophobic association, and has at least one type selected from nonionic ethylenically unsaturated monomers, cationic ethylenically unsaturated monomers, or anionic ethylenically unsaturated monomers monomeric copolymers.

HAP is highly associative and can form a network in aqueous solution, as evidenced by lower tan δ values than similar polymers without hydrophobic modification, as determined by viscoelastic characterization of 0.5% solutions. When HAP is applied to pulp furnishes, retention and drainage activity are significantly improved while maintaining satisfactory sheet formation, a unique property not achieved by conventional flocculants.

HAP can include: at least one hydrophobic ethylenically unsaturated monomer in an amount from about 0.001 mole percent to about 10 mole percent, and a nonionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an anionic ethylenically unsaturated monomer At least one monomer that is an unsaturated monomer, provided that said at least one hydrophobic ethylenically unsaturated monomer does not contain 2,4,6-triphenylethylbenzene.

式1The at least one hydrophobic ethylenically unsaturated monomer may be: an ethylenically unsaturated monomer having at least one hydrophobic side group of the following general structure.

Formula 1

In the formula, R ₁ is hydrogen or methyl; R ₂ when present is -CH ₂ -, -C(O)-O-, -OC(O)-, -C(O)-NR ₆ -, -NR ₆ -C(O)- or -O-; R ₃ when present is -(-CH ₂ -CHR ₁ -O-) _n -, C ₁ -C ₂₀ alkyl, or C ₁ -C ₂₀ hydroxyalkyl, wherein n is equal to 1-40, R ₁ is as described above; R ₄ when present is -NR ₆ - or -N ⁺ (R ₆ ) ₂ -; R ₅ is one or more hydrophobic side groups selected from the following: C ₄ -C ₂₀ alkyl group, C ₄ -C ₂₀ cycloalkyl group, polynuclear aromatic hydrocarbon group, alkaryl group in which the alkyl group has one or more carbon atoms, or haloalkyl group with 4 or more carbon atoms; R ₆ when present is hydrogen, methyl, CH ₂ =CR ₁ -CH ₂ -, corresponding to the hydrophobic side group R ₅ as described above, or a mixture thereof; when R ₄ is -N ⁺ (R ₆ ) ₂ - , Z is the conjugate base of the acid; the prerequisite is that R ₅ is not 2,4,6-tribenzoethylbenzene.

The polynuclear aromatic hydrocarbon may be naphthyl. The haloalkyl group of four or more carbon atoms may be a perfluoroalkyl group, preferably selected from one or more of C ₄ F ₉ -C ₂₀ F ₄₁ . The side hydrophobic groups may be polyalkylene oxide groups, wherein the alkylene group is propylene or higher and each hydrophobic portion has at least one alkylene oxide unit or may be selected from one or more A C ₄ -C ₂₀ alkyl group is alternatively preferably selected from one or more C ₈ -C ₂₀ alkyl groups.

Preferably, the hydrophobic ethylenically unsaturated monomer described in formula 1 may be selected from: esters of one or more hydrocarbons of unsaturated carboxylic acids and their salts, N-alkyl ethylenically unsaturated amides, α- Olefins, vinyl esters, vinyl ethers, N-vinylamides, alkylstyrenes, alkyl polyalkylene glycol (meth)acrylates, or N-alkyl ethylenically unsaturated cationic monomers. The olefinic carboxylic acids may preferably be selected from: C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid, more preferably from dodecyl acrylate or dodecyl methacrylate. The ethylenically unsaturated amides may preferably be selected from N-octadecyl acrylamide, N-octadecyl methacrylamide, or N,N-dioctyl acrylamide. The alpha-olefin may preferably be selected from: 1-octene, 1-decene, 1-dodecene, or 1-hexadecene. The vinyl ester may preferably be selected from: vinyl laurate or vinyl stearate. Vinyl alkyl ethers may preferably be selected from: dodecyl vinyl ether or hexadecyl vinyl ether. N-vinylamide may preferably be selected from: N-vinyl lauramide or N-vinyl stearamide. Alkylstyrenes may preferably be selected from: tert-butylstyrene. Alkyl polyethylene glycol (meth)acrylates may preferably be selected from: lauryl polyethylene glycol (23) methacrylate. N-Alkyl ethylenically unsaturated cationic monomers may preferably be selected from the group consisting of C ₁₀ -C ₂₀ alkyl halide quaternary salts of methyldiallylamine, N,N dialkylaminoalkyl (meth)acrylamides .

The at least one nonionic ethylenically unsaturated monomer can be one or more of acrylamide, methacrylamide, N-alkylacrylamide, N,N-dialkylacrylamide, methyl acrylate, methacrylic acid Methyl esters, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, or N-vinylpyrrolidone. N-alkylacrylamides are preferably selected from N-methacrylamides and N,N-dialkylacrylamides are preferably selected from N,N-dimethylacrylamides. The at least one nonionic ethylenically unsaturated monomer is preferably one or more of acrylamide, methacrylamide, or N-methacrylamide, more preferably acrylamide.

The at least one anionic ethylenically unsaturated monomer may be one or more of acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropanesulfonate, sulfoethyl (meth)acrylate, vinyl Sulfonic acid, styrenesulfonic acid, maleic acid or their salts, preferably one or more acrylic acid, methacrylic acid or their salts, more preferably one or more sodium or ammonium acrylic acid salts .

The at least one cationic ethylenically unsaturated monomer may be selected from: one or more diallylamines, (meth)acrylates of dialkylaminoalkyl compounds, (meth)acrylates of dialkylaminoalkyl compounds base) acrylamide, N-vinylamine hydrolysis products of N-vinylformamide, and their salts and quaternary compounds. The quaternary salt of diallylamine may preferably be selected from diallyldimethylammonium chloride. Dialkylaminoalkyl (meth)acrylamide is preferably selected from N,N-dimethylaminopropylacrylamide, and its acid or quaternary salt can preferably be selected from N,N,N-trimethylaminopropylacrylamide chloride . Dialkylaminoalkyl (meth)acrylates can preferably be selected from: N, N-dimethylaminoethyl acrylate, and its acid or quaternary salt can preferably be selected from: N, N, N-trimethylaminoethyl acrylate chloride. The at least one cationic ethylenically unsaturated monomer may also be selected from one or more compounds of the general formula: Formula 2

In the formula

R ₁ is hydrogen or methyl,

R ₂ , R ₃ and R ₄ are hydrogen, C ₁ -C ₃ alkyl, or hydroxyethyl,

R ₂ and R ₃ or R ₂ and R ₄ can be combined to form a ring containing one or more heteroatoms, Z is the conjugate base of an acid,

X is oxygen or NR ₁ , where R ₁ is as described above, and

式3A is a C ₁ -C ₁₂ alkylene group; or

Formula 3

In the formula, _R5 and _R6 are hydrogen or methyl,

R ₈ of R ₇ is hydrogen, C ₁ -C ₃ alkyl, or hydroxyethyl; and

Z as above;

式4

式5式6or N-vinylformamide and the associated hydrolyzate represented by the following repeating unit.

Formula 4

Formula 5 Formula 6

In the formula, R ₁ , R ₂ and R ₃ are each hydrogen or C ₁ -C ₃ alkyl,

Z as above.

It should be noted that the description of hydrophobic ethylenically unsaturated monomers includes the cationic ethylenically unsaturated monomers described in formulas 2-6, where, for example, R2 in formulas ₂ , 4-5 and _R7 in formula 3 The definition is replaced by the side group hydrophobic moiety R ₅ in formula 1.

Preferably, the HAP according to the invention (0.5% aqueous solution of HAP) has a dynamic oscillation frequency sweep tan δ value at 0.0068 Hz lower than the tan δ value of a similar polymer not containing hydrophobic ethylenically unsaturated monomers, more preferably less than 1. It is also preferred that at least one hydrophobic ethylenically unsaturated monomer group is present in an amount of from about 0.01 mole percent to about 10 mole percent, more preferably from about 0.1 mole percent to about 5.0 mole percent.

The HAP used in the present invention may be anionic, nonionic, cationic or amphoteric copolymers, preferably anionic copolymers. The anionic copolymer may include at least one hydrophobic ethylenically unsaturated monomer and at least one anionic ethylenically unsaturated monomer and may additionally include at least one nonionic ethylenically unsaturated monomer.

Anionic copolymers can include from about 0.01 mole percent to about 10 mole percent of at least one hydrophobic ethylenically unsaturated monomer, from about 1 mole percent to about 99.999 mole percent of at least one anionic ethylenically unsaturated monomer, and about 1 mole percent % to about 99.999 mole % of at least one nonionic ethylenically unsaturated monomer; preferably about 0.01 mole % to about 5 mole % of at least one hydrophobic ethylenically unsaturated monomer, about 10 mole % to about 90 Mole % of at least one anionic ethylenically unsaturated monomer, and from about 10 mole % to about 90 mole % of at least one nonionic ethylenically unsaturated monomer; more preferably from about 0.1 mole % to about 2.0 mole % of At least one hydrophobic ethylenically unsaturated monomer; about 30 mole % to about 70 mole % of at least one anionic ethylenically unsaturated monomer, and about 50 mole % to about 70 mole % of at least one nonionic ethylenically unsaturated monomer saturated monomer.

The cellulose slurry of the present invention comprising HAP may also comprise other components arbitrarily selected by those of ordinary skill in the art, such as at least one flocculant, at least one starch, at least one inorganic or organic coagulant, or at least one filler .

In addition, the present invention also includes cellulosic paper sheets produced by the method of the present invention. The cellulosic sheets may include HAP-incorporated paper and paperboard.

In addition, the present invention also relates to a method for preparing a cellulosic fiber composition, said method comprising adding HAP to a cellulosic slurry, and to a cellulosic fiber composition comprising cellulosic pulp and an aqueous slurry of HAP, wherein HAP comprising at least one hydrophobic ethylenically unsaturated monomer in an amount from about 0.001 mole percent to about 10 mole percent and selected from one or more C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid; and at least one A monomer selected from the group consisting of: a) from about 1 mole % to about 99.999 mole % of at least one nonionic ethylenically unsaturated monomer selected from one or more of the following: acrylamide, methacryl Amide, N-alkylacrylamide, N,N-dialkylacrylamide, methyl acrylate, methyl methacrylate, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, Vinyl acetate, or N-vinylpyrrolidone; b) from about 1 mole percent to about 99.999 mole percent of at least one anionic ethylenically unsaturated monomer selected from one or more of the following: acrylic acid, methacrylic acid , 2-acrylamido-2-methylpropanesulfonate, sulfoethyl-(meth)acrylate, vinylsulfonic acid, styrenesulfonic acid, maleic acid or their salts; or c) about 1 Mole % to about 99.999 mole % of at least one cationic ethylenically unsaturated monomer selected from one or more of the following: diallylamine, (meth)acrylates of dialkylaminoalkyl compounds , (meth)acrylamides of dialkylaminoalkyl compounds, N-vinylamine hydrolyzates of N-vinylformamides, and their salts and quaternary compounds.

HAP may preferably include at least one hydrophobic ethylenically unsaturated monomer in an amount from about 0.001 mole % to about 10 mole % and selected from one or more _C10 - _C20 alkyl esters of acrylic acid and methacrylic acid; and at least one monomer selected from a) from about 1 mole % to about 99.999 mole % of at least one nonionic ethylenically unsaturated monomer selected from one or more of the following: acrylamide, Methacrylamide, or N-alkylacrylamide; b) from about 1 mole percent to about 99.999 mole percent of at least one anionic ethylenically unsaturated monomer selected from one or more of the following: acrylic acid, methacrylic acid or their salts; or c) from about 1 mole percent to about 99.999 mole percent of at least one cationic ethylenically unsaturated monomer selected from one or more of the following: N,N-dialkyl Aminoalkylacrylates, N,N-dialkylaminoalkylmethacrylates, acids or quaternary salts thereof. Preferably, at least one hydrophobic ethylenically unsaturated monomer may be selected from one or more of lauryl acrylate or lauryl methacrylate, and the nonionic ethylenically unsaturated monomer may be acrylamide , at least one anionic ethylenically unsaturated monomer can be selected from one or more sodium or ammonium salts of acrylic acid, and the cationic ethylenically unsaturated monomer can be chlorine of N,N-dimethylaminoethyl acrylate methane.

Those skilled in the art can optionally add auxiliary components, such as at least one flocculant, at least one starch, at least one coagulant, or at least one filler, to the above slurry containing HAP.

In addition, the present invention also relates to a method for preparing a cellulose fiber composition, said method comprising adding anionic HAP to a cellulose slurry, and the present invention also relates to an aqueous slurry comprising cellulose pulp and anionic HAP, wherein the anionic HAP is preferably comprising at least one hydrophobically unsaturated monomer selected from one or more of lauryl acrylate or lauryl methacrylate, at least one nonionic ethylenically unsaturated monomer being acrylamide, and at least one anionic ethylenically The unsaturated monomer is acrylic acid. In addition, other components arbitrarily selected by those skilled in the art may be added to the cellulose slurry of the present invention comprising HAP, such as at least one flocculant, at least one starch, at least one inorganic or organic coagulant, or at least A filler. In addition, the present invention also relates to a cellulose sheet produced by the aforementioned method and the aforementioned composition. The cellulosic sheets may include HAP-incorporated paper and paperboard.

The cellulose fiber composition of the present invention preferably comprises the above-mentioned HAP and its viscoelasticity. Preferred cellulosic fiber compositions of the present invention include paper.

Description of the Invention 1. Definitions

The term "HAP" as used herein refers to the hydrophobically associating polymers of the present invention.

The term "hydrocarbon" as used herein includes "aliphatic hydrocarbons", "cycloaliphatic hydrocarbons", and "aromatic hydrocarbons". Unless otherwise stated, the terms "aliphatic hydrocarbon" and "cycloaliphatic hydrocarbon" should be understood to include "alkyl", "alkenyl", and "cycloalkyl". Unless otherwise stated, the term "aromatic hydrocarbon" should also be understood to include "aryl", "aralkyl", and "alkaryl".

Hydrocarbyl should be understood to include unsubstituted hydrocarbyl and substituted hydrocarbyl, the latter meaning that the hydrocarbon moiety other than carbon and hydrogen bears additional substituents. Thus, aliphatic, cycloaliphatic, and aromatic groups are understood to include unsubstituted aliphatic, cycloaliphatic, and aromatic groups as well as substituted aliphatic, cycloaliphatic, and Group, and aromatic group, the latter means that in addition to carbon and hydrogen, aliphatic groups, cycloaliphatic groups, and aromatic groups carry additional substituents.

Copolymers as described above should be understood to include polymers consisting of, or consisting essentially of, or essentially consisting of, two different monomeric units. In addition, copolymers should also be understood to include polymers incorporating three or more different monomer units, such as terpolymers and the like. 2. The method of the present invention

The present invention includes processes for the production of cellulosic fiber compositions - in particular webs of cellulosic fibers, especially sheets of cellulosic fibers, more particularly paper and board. The method comprises: adding at least one HAP to a suitable paper furnish, such as a cellulosic fiber pulp or stock, especially lignocellulosic fiber pulp or stock.

Preferably, the polymer is added to the slurry comprising the aqueous suspension of the furnish. It is also preferred that a cellulosic sheet - especially a paper sheet, more particularly paper or board - is formed from the slurry.

The method of the present invention comprises the steps of: providing a papermaking furnish consisting of cellulosic fibers with or without additional inorganic fillers suspended in water; depositing the furnish onto a papermaking wire or fabric; and dewatering the slurry to remove the solids. The components form a sheet; wherein in the process, at one or more locations, at least one HAP is added. Preferably, the polymer is introduced into the fiber slurry prior to the dewatering procedure.

The HAP acts to increase fines retention and/or to increase fiber dewatering. The polymers are particularly effective at providing filler retention (when used) and cellulosic fiber fines retention which are generated from the fibers during the process of the invention. A prerequisite is that HAPs form a physical network in aqueous solution through their hydrophobic groups, as evidenced by their viscoelasticity. Since the three-dimensional structure of HAP is less adsorbed on the particle surface, it provides better bridging between particles, which will lead to better retention and dehydration activity.

Viscoelasticity as described here (Rheology: Principles, Measurements, and Applications, C.W. Macosko, Wiley, New York, NY.) shows the response time in terms of deformation, i.e., for short times, the material is stiff and glassy, while at longer times the material is rubbery or viscous. A common way to measure this phenomenon is through stress relaxation, where an instantaneous strain is imposed on the material and the resulting stress delay is recorded over time. A purely viscous material will exhibit zero stress once the strain deformation becomes constant, whereas an elastic solid will have no stress delay. A viscoelastic material will exhibit a stress delay between these two limits; thus exhibiting a combined elastic and viscous response, or viscoelasticity.

A dynamic oscillatory characterization was performed for the HAP material in order to determine the viscoelasticity, wherein the specimen was subjected to sinusoidal deformation. The test is carried out with a stress sweep, where a constant frequency is applied with increasing stress (amplitude), or conversely, with a frequency sweep, where a constant stress is applied with a varying frequency. The measured strain of the elastic component of the material will be in phase with the applied stress, whereas the viscous component of the material will be out of phase by 90 degrees. Tan δ is the ratio of viscosity to elasticity of the material and characterizes the material as exhibiting greater viscosity or elasticity. Thus, a material with tan δ greater than 1 will exhibit predominantly viscous at a particular frequency, and will be predominantly elastic when tan δ is less than 1.

HAP can be used as the sole retention/drainage aid. Additionally, the polymer may also be used in combination with at least one flocculant, such as a conventional papermaking flocculant, for example a high MW cationic, anionic, or nonionic flocculant.

The method of the present invention can be practiced using the papermaking apparatus or system described herein. It should be noted that the method of the present invention is not limited to a specific device or system, which is provided as a representative example that can be used.

As reviewed in the Pulp and Paper Technology Handbook (G.A. Smook, TAPPI Press, Atlanta, GA), pulp components are typically metered into the paper machine sump at a consistency value of 2.8-3.2 wt%. The paper machine stock chest usually contains the final mix, but in some cases it is also possible to add low concentrations of additives just before the headbox. The paper machine stock chest stock is normally circulated to a constant headbox container which feeds the stock to the machine inlet system through a control valve (dosing valve).

The heart of the entry system is the mix pump, which mixes the stock with white water and delivers the blend to the headbox. Here, the stock is mixed with circulating white water from the underwire white sump and the consistency is reduced to that required for the headbox (typically between about 0.5 wt% and about 1.0 wt%).

White water with a solids concentration of typically about 0.1 wt% or less is liquid from pulp dewatering that drains off the papermaking wire into the white sump below the wire.

After the mix pump, the pulp usually passes through a centrifugal cleaner, then through a pressure screen, to the headbox.

Centrifugal cleaners remove debris such as chips and flakes, while pressure screens remove dense impurities and deflocculate fibers. The function of the headbox is to distribute the stock onto the previously indicated endlessly moving papermaking wire or fabric; said papermaking wire or fabric may be a fourdrinier or twin wire former.

On a moving papermaking wire or fabric, the stock is dewatered; the resulting liquid is white water drained from the stock into the white water pit under the wire as described above. The drainage forms the slurry into a sheet carried on a Fourdrinier wire or fabric for transport to the press section.

During conveyance through the press section, the sheet is pressed between press rolls and thus further dewatered. The sheet continues through the press into a dryer section where it is additionally dried. From the drying section, the sheet continues to pass through the calender roll set. In the calender stack, the paper sheet is pressed between metal rolls, which reduces the thickness and smoothes the surface.

From the calender roll set, the paper sheet is wound onto a paper shaft.

The resulting paper can also be coated with sizing or coating materials.

The material used in the method of the invention comprises cellulose pulp and at least one HAP. Additionally, one or more additional materials can also be used, including at least one starch, at least one filler, at least one inorganic or organic coagulant, and at least one conventional flocculant.

When a flocculant is used, the flocculant and HAP can be added simultaneously, or at different locations in a method without intermittent shear locations, or at different locations with intermittent shear locations between their respective addition locations. Preferably, flocculant and HAP are added sequentially to the method of the present invention, ie added at different positions or times. Flocculant can be added before or after HAP.

When added sequentially, the slurry can be sheared prior to the point of flocculant and HAP addition. In the plant or system discussed in this invention, high shear occurs in the mixer pump, centrifugal cleaner, and pressure screen.

Consistent with the foregoing, it is preferred to provide such a device or system with suitable feeding locations for the addition of the aforementioned materials, such as flocculants and HAP. Therefore, the flocculant and/or HAP can be added at the feeding position before the mixing pump (for example, between the dosing valve and the mixing pump), and/or at the feeding position before the centrifugal cleaner (for example, at the between the mixing pump and the centrifugal cleaner), and/or at the feeding position before the pressure screen (for example, between the centrifugal cleaner and the pressure screen).

Starch, fillers, or flocculants can be added at many points within the process relative to where other materials are fed, as known to those of ordinary skill in the art.

The order of addition of the different materials introduced into the method of the present invention is not limited to those described above, but is generally based on the facts and properties of each particular application. 3. Materials used a. Cellulose pulp

Suitable cellulosic fiber pulps for use in the process of the present invention include: conventional papermaking pulps, such as conventional chemical pulps. For example, bleached and unbleached kraft and sulphite pulps can be used, mechanical pulps such as groundwood, thermomechanical pulp, chemi-thermomechanical pulp, recycled pulp such as old corrugated boxes, newsprint , office waste paper, magazine paper and other non-deinking waste paper, deinking waste paper, and mixtures thereof. b.starch

Starches add strength properties, in particular dry strength, to the cellulosic products obtained by the process of the invention. In particular, starch will increase interfiber bonding in the stock. Starch will also have an effect on drainage performance.

Starches that can be used in the method of the present invention include cationic starches and amphoteric starches. Suitable starches include those derived from corn, potato, wheat, rice, tapioca, and the like.

Cationicity is imparted by introducing cationic groups, while amphotericity is obtained by additionally introducing anionic groups. For example, cationic starches are obtained by reacting starch with tertiary amines or with quaternary ammonium compounds such as: dimethylaminoethanol and 3-chloro-2-hydroxypropyltrimethylammonium chloride. Cationic starches preferably have a degree of cationic substitution (D.S.)—that is, the average number of cationic groups per anhydroglucose unit substituted for a hydroxyl group—from about 0.01 to about 1.0, more preferably from about 0.01 to about 0.10, more preferably from about 0.02 -0.04.

Amphoteric starches can be provided by introducing various anionic groups. Preferred amphoteric starches are those starches which are net cationic.

As an example, anionic phosphate groups can be introduced into cationic starches by reaction with phosphates or phosphate etherifying agents. Wherein, the cationic starch raw material is starch diethylaminoethyl ether, and the dosage of the phosphate preparation used in the modification is preferably based on the ability to provide about 0.07-0.18 moles of anionic groups per mole of cationic groups.

Other amphoteric starches that can be used are: amphoteric starches prepared by introducing sulfosuccinate groups into cationic starches. This modification is accomplished by adding maleate half ester groups to the cationic starch and reacting the maleate double bond with sodium bisulfite.

As further examples cationic starches can be etherified with 3-chloro-2-sulfopropionic acid, carboxyl groups can be introduced into starch by reaction with sodium chloroacetate or oxidation with hypochlorite, And propane sultone can be used to treat cationic starch to provide amphotericity.

Additional useful amphoterics can be obtained by xanthation of diethylaminoethylammonium starch ether and 2-(hydroxypropyl)trimethylammonium starch ether.

Furthermore, the modification can be extended by treatment with ethylene oxide or propylene oxide, by introducing nonionic or hydroxyalkyl groups.

In the process of the present invention, starch is preferably used in a proportion of from about 1 pound to about 100 pounds per ton of cellulosic pulp, based on the dry weight of the pulp. More preferably, the concentration of the starch is from about 2.5 pounds to about 50 pounds per ton of pulp, more preferably from about 5 pounds to about 25 pounds. c. Filler

Fillers provide optical properties to cellulosic products. It will give opacity and brightness to the final sheet and improve its printing properties. Suitable fillers include: calcium carbonate (naturally occurring ground calcium carbonate and synthetically produced precipitated calcium carbonate), titanium oxide, talc, clay, and gypsum. Fillers are used in amounts of up to about 50% by weight filler in the cellulosic product based on the dry weight of the pulp. d. coagulant

Coagulants are used in addition to coagulants and or HAPs to increase retention and drainage. The coagulants employed can be inorganic or organic.

The most commonly used inorganic coagulants are aluminas. Suitable examples include: technical grade aluminum sulfate (alum), polyaluminum chloride, aluminum polyhydroxychloride, aluminum polyhydroxysulfate, sodium aluminate, and the like. Organic coagulants are generally synthetic polymeric materials. Suitable examples include: hydrolysates and quaternized hydrolysates of polyamines, poly(aminoamines), polyDADMACs, polyethyleneimines, N-vinylformamide polymers and copolymers, and the like.

In the process of the present invention, the coagulant is preferably used in a proportion of from about 0.01 lb to about 50 lb per ton of cellulosic pulp, based on the dry weight of the pulp. More preferably, the concentration of the coagulant is from about 0.05 pounds to about 20 pounds per ton of pulp, more preferably from about 0.1 pounds to about 10 pounds. e. Flocculants

Ionic flocculants customary in the field of papermaking are suitable as flocculants for the process of the invention. Cationic, anionic, nonionic, and amphoteric flocculants can be used, especially cationic, anionic, nonionic, and amphoteric polymers.

Polymers suitable for use as flocculants in the process of the present invention include homopolymers of nonionic ethylenically unsaturated monomers. It is also possible to use copolymers comprising two or more nonionic ethylenically unsaturated monomers, such as copolymers comprising at least one nonionic ethylenically unsaturated monomer and at least one cationic ethylenically unsaturated monomer. unsaturated monomers and/or at least one anionic ethylenically unsaturated monomer.

Nonionic, cationic, and anionic ethylenically unsaturated monomers that can be used are those discussed herein, as monomers suitable for the at least one HAP of the present invention.

Suitable nonionic ethylenically unsaturated monomers include: acrylamide; methacrylamide; N-alkylacrylamide, such as N-methacrylamide; N,N-dialkylacrylamide, such as N,N- Dimethacrylamide; methyl acrylate; methyl methacrylate; acrylonitrile; N-vinylmethylacetamide; N-vinylmethylformamide; vinyl acetate; N-vinylpyrrolidone; (methyl ) hydroxyalkyl acrylates such as hydroxyethyl (meth)acrylate or hydroxypropyl (meth)acrylate; mixtures of any of the foregoing, etc. Among the foregoing, acrylamide, methacrylamide, and N-alkylacrylamide are preferred, and acrylamide is particularly preferred.

Cationic ethylenically unsaturated monomers that can be used are: diallylamine, (meth)acrylates of dialkylaminoalkyl compounds, (meth)acrylamides of dialkylaminoalkyl compounds, and their salts and quaternary compounds. Preferred are N,N-dialkylaminoalkyl acrylates and N,N-dialkylaminoalkyl methacrylates, and their acids and quaternary salts, wherein N,N-dimethylaminoethylacrylic acid The methyl chloride quaternary compound of the ester is particularly preferred. In addition, as regards cationic monomers, suitable examples include those of the following general formula:

In the formula, R ₁ is hydrogen or methyl, R ₂ is hydrogen or C ₁ -C ₄ lower alkyl, R ₃ and/or R ₄ is hydrogen, C ₁ -C ₁₂ alkyl, aryl, or hydroxyethyl , R ₂ and R ₃ or R ₂ and R ₄ can be combined to form a ring containing one or more heteroatoms, Z is the conjugate base of an acid, X is oxygen or NR ₁ , where R ₁ is as described above, and A is C ₁ -C ₁₂ alkylene group; or

Wherein R ₅ and R ₆ are hydrogen or methyl, R ₇ is hydrogen or C ₁ -C ₁₂ alkyl, R ₈ is hydrogen, C ₁ -C ₁₂ alkyl, benzyl, or hydroxyethyl; Z is as above; or N-vinylformamide and the associated hydrolyzate represented by the following repeating unit:

In the formula, R ¹ , R ² and R ³ are each H or C ₁ -C ₃ alkyl, and Z is as described above.

Suitable anionic ethylenically unsaturated monomers include: acrylic acid, methacrylic acid, and their salts; 2-acrylamido-2-methylpropane sulfonate; sulfoethyl (meth)acrylate; vinyl sulfonate acid; styrenesulfonic acid; and maleic acid and other dibasic acids and their salts. Acrylic acid, methacrylic acid and their salts are preferred, among which sodium and ammonium salts of acrylic acid are particularly preferred.

Monomers can be polymerized into polymers by a variety of initiator systems, including free radical (thermal and redox) synthesis, cationic synthesis, and anionic synthesis. Flocculant polymers can be prepared by a variety of common means, including bulk polymerization, solution polymerization, dispersion polymerization, and emulsion/inverse emulsion polymerization. The resulting polymers can be provided in a variety of physical forms depending on the end use, including aqueous solutions, dry solid powders, dispersions, and emulsions.

Flocculants can be nonionic, cationic, anionic, or amphoteric. The nonionic polymer flocculant will comprise one or more of the aforementioned nonionic monomers.

The cationic polymer flocculant will comprise one or more of the cationic monomers described above. The total amount of cationic monomer is from about 1-99% in molar concentration, preferably from about 2-50%, more preferably from about 5-40% cationic monomer, and the remaining monomer is one of the aforementioned nonionic monomers .

The anionic polymer flocculant will comprise one or more of the anionic monomers described above. The total amount of anionic monomer is from about 1-99% in molar concentration, preferably from about 2-50%, more preferably from about 5-40% anionic monomer, and the remaining monomer is one of the aforementioned nonionic monomers .

The amphoteric polymeric flocculant will comprise a mixture of one or more of the cationic and anionic monomers described above. Preference is given to any mixtures of cationic and anionic monomers, provided that at least one cationic monomer and at least one anionic monomer are used. The polymer may contain excess cationic monomer, excess anionic monomer, or equal amounts of anionic monomer and anionic monomer. The total amount of ionic monomers, i.e. the composite amount of cationic monomers and anionic monomers, is from about 1-99% moles in terms of molar concentration, preferably from about 2-80% moles, more preferably from about 5-40% moles cationic monomer, and the remaining monomers are one of the aforementioned nonionic monomers.

In the process of the present invention, the flocculant is preferably employed in a proportion of from about 0.01 lb to about 10 lb per ton of cellulosic pulp, based on the active polymer and based on the dry weight of the pulp. More preferably, the concentration of the flocculant is from about 0.05 pounds to about 5 pounds per ton of pulp, more preferably from about 0.1 pounds to about 1 pound. f. Hydrophobically Associating Polymers (HAP)

The present invention comprises at least one HAP. Suitable HAPs for the present invention include: copolymers containing at least one hydrophobic, ethylenically unsaturated monomer, with the proviso that the at least one hydrophobic, ethylenically unsaturated monomer does not contain 2,4,6-tribenzoethylene Benzene. These copolymers additionally comprise at least one nonionic ethylenically unsaturated monomer, and/or at least one cationic ethylenically unsaturated monomer, and/or at least one anionic ethylenically unsaturated monomer.

The hydrophobic ethylenically unsaturated monomers indicated include: water-insoluble hydrophobic, ethylenically unsaturated monomers. In addition, with respect to hydrophobic ethylenically unsaturated monomers, they include ethylenically unsaturated monomers, especially water-insoluble monomers having hydrophobic groups, and monomeric surfactants. Hydrophobic groups include hydrophobic organic groups, such as those having a hydrophobicity comparable to: aliphatic hydrocarbon groups having at least four carbon atoms, such as _C4 - _C20 alkyl and cycloalkane groups; polynuclear aromatic hydrocarbon groups such as benzyl, substituted benzyl and naphthyl, provided that the substituted benzyl is not 2,4,6-trithenylbenzene; wherein the alkyl group has one or more an alkaryl group of four or more carbons; a haloalkyl group of four or more carbons, preferably a perfluoroalkyl group; a polyalkyleneoxy group wherein the alkylene group is propylene or higher and each The hydrophobic portion has at least one alkylene oxide unit. Preferred hydrophobic groups include those having at least 4 carbons or more per hydrocarbyl group, such as _C4 - _C20 alkyl groups or at least 4 carbons or more per fluorohydrocarbon group carbons, such as C ₄ F ₉ -C ₂₀ F ₄₁ . Particular preference is given to C ₈ -C ₂₀ alkyl groups.

Suitable hydrocarbyl-containing ethylenically unsaturated monomers include esters or amides of _C4 and higher alkyl groups.

Particularly suitable esters include: lauryl acrylate, lauryl methacrylate, tridecyl acrylate, tridecyl methacrylate, myristyl acrylate, tetradecyl methacrylate Alkyl esters, octadecyl acrylate, octadecyl methacrylate, nonyl-alpha-phenyl acrylate, nonyl-alpha-phenyl methacrylate, dodecyl-alpha-phenyl acrylate phenyl ester, and dodecyl-alpha-phenyl methacrylate.

C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid are preferred. Among them, lauryl acrylate and lauryl methacrylate are particularly preferred.

In addition, the following ethylenically unsaturated monomers containing hydrocarbon groups can also be used:

--N-Alkyl ethylenically unsaturated amides, such as N-octadecyl acrylamide, N-octadecyl methacrylamide, N,N-dioctyl acrylamide and their similar derivatives;]

--α-Olefins, such as 1-octene, 1-decene, 1-dodecene, and 1-hexadecene;

-- vinyl esters in which the ester has at least eight carbons, such as vinyl laurate and vinyl stearate;

-- Vinyl ethers, such as dodecyl vinyl ether and hexadecyl vinyl ether;

--N-vinyl amides, such as N-vinyl lauramide and N-vinyl stearamide;

-- Alkylstyrenes, such as tert-butylstyrene;

-- Alkyl polyethylene glycol (meth)acrylates, such as lauryl polyethoxylate (meth)acrylate (23); and

--N-Alkyl ethylenically unsaturated cationic monomers, such as C ₁₀ -C ₂₀ alkyl halide quaternary salts of methyldiallylamine, N,N-dimethylaminoalkyl (meth)acrylic acid esters, and N,N-dialkylaminoalkyl(meth)acrylamides.

Suitable nonionic ethylenically unsaturated monomers include: acrylamide; methacrylamide; N-alkylacrylamide, such as N-methacrylamide; N,N-dialkylacrylamide, such as N,N- Dimethacrylamide; methyl acrylate; methyl methacrylate; acrylonitrile; N-vinylmethylacetamide; N-vinylmethylformamide; vinyl acetate; N-vinylpyrrolidone; any of the foregoing mixture etc. Among these, preferred are acrylamide, methacrylamide, and N-alkylacrylamide, among which acrylamide is particularly preferred.

Cationic ethylenically unsaturated monomers that can be used are: diallylamine, (meth)acrylates of dialkylaminoalkyl compounds, (meth)acrylamides of dialkylaminoalkyl compounds, N- N-vinylamine hydrolysis products of vinylformamide, their salts and quaternary compounds. Preferred are N,N-dialkylaminoalkyl esters of acrylic acid and methacrylic acid, and their acids and quaternary salts, of which the methyl chloride quaternary of N,N-dimethylaminoethyl acrylate is particularly preferred. compounds.

In addition, with regard to cationic monomers, suitable examples include those of the following general formula:

In the formula, R ₁ is hydrogen or methyl; R ₂ , R ₃ and R ₄ are hydrogen, C ₁ -C ₃ alkyl, or hydroxyethyl; and R ₂ and R ₃ or R ₂ and R ₄ can be combined to form a ring of one or more heteroatoms; Z is the conjugate base of an acid; X is oxygen or NR ₁ , where R ₁ is as defined above; and A is a C ₁ -C ₁₂ alkylene group; or

In the formula, R ₅ and R ₆ are hydrogen or methyl, R ₇ and R ₈ are hydrogen, C ₁ -C ₃ alkyl, or hydroxyethyl; Z is as defined above; or N-vinylformamide and the following repeating units Represents the associated hydrolyzate:

In the formula, R ¹ , R ² and R ³ are each hydrogen or C ₁ -C ₃ alkyl, and Z is as defined above.

Suitable anionic ethylenically unsaturated monomers include acrylic acid, methacrylic acid and their salts; 2-acrylamido-2-methylpropanesulfonate; sulfoethyl (meth)acrylate; vinylsulfonic acid ; Styrene sulfonic acid; and other dibasic acids and their salts. Acrylic acid, methacrylic acid and their salts are preferred, and sodium and ammonium salts of acrylic acid are particularly preferred.

Preferably, the proportion of hydrophobic ethylenically unsaturated monomers in the HAP is in a range such that the polymers are hydrophobically associated—that is, the concentration of the hydrophobic monomer is low enough that the polymer is still water-soluble or water-dispersible, but sufficient to provide The association properties discussed here. In this regard, it is preferred that the at least one HAP comprises from about 0.001 mole % to about 10 mole %, more preferably from about 0.01 mole % to about 5 mole %, more preferably from about 0.1 mole % to about 2.0 mole % of at least one Hydrophobic ethylenically unsaturated monomer.

HAPs useful in the present invention include: anionic, nonionic, and cationic as well as amphoteric copolymers. Of these, anionic copolymers are preferred.

Anionic copolymers comprise at least one hydrophobic ethylenically unsaturated monomer and at least one anionic ethylenically unsaturated monomer. It is preferred that the anionic copolymer additionally comprises at least one nonionic ethylenically unsaturated monomer. Particularly preferred are terpolymers consisting of at least one hydrophobic ethylenically unsaturated monomer, at least one anionic ethylenically unsaturated monomer, and at least one nonionic ethylenically unsaturated monomer, or consisting essentially of Constituent terpolymers, or terpolymers consisting essentially thereof.

For anionic copolymers, preferred hydrophobic ethylenically unsaturated monomers are hydrocarbon esters of α,β-ethylenically unsaturated carboxylic acids and their salts, particularly preferred are dodecyl acrylate and dodecyl methacrylate. base ester. Preferred nonionic ethylenically unsaturated monomers are acrylamide and methacrylamide and methacrylamide. Preferred anionic ethylenically unsaturated monomers are acrylic acid and methacrylic acid.

The anionic copolymer preferably comprises from about 0.001 mole percent to about 10 mole percent of a hydrophobic ethylenically unsaturated monomer, from about 1 mole percent to about 99.999 mole percent of a nonionic ethylenically unsaturated monomer, and from about 1 mole percent to about 99.999 mole percent % of at least one anionic ethylenically unsaturated monomer. More preferably, they comprise from about 0.01 mole % to about 5 mole % of at least one hydrophobic ethylenically unsaturated monomer, from about 10 mole % to about 90 mole % of at least one nonionic ethylenically unsaturated monomer, and from about 10 mole percent to about 90 mole percent of at least one anionic ethylenically unsaturated monomer. More preferably, they contain from about 0.1 mole percent to about 2.0 mole percent ethylenically unsaturated monomers. More preferably, they comprise from about 0.1 mole % to about 2.0 mole % of at least one hydrophobic ethylenically unsaturated monomer, from about 50 mole % to about 70 mole % of at least one nonionic ethylenically unsaturated monomer, and from about 30 mole percent to about 70 mole percent of at least one anionic ethylenically unsaturated monomer.

The monomers can be polymerized into HAP polymers by a variety of initiator systems, including free radical (thermal and redox), cationic, and anionic synthesis. HAP can be prepared by a variety of common means, including bulk polymerization, solution polymerization, micellar solution polymerization, dispersion polymerization, and emulsion/inverse emulsion polymerization. The resulting polymers can be provided in a variety of physical forms depending on the end use, including aqueous solutions, dry solid powders, dispersions, and emulsions.

HAP is preferably used in the present invention in an amount of from about 0.01 pound to about 10 pounds per ton of cellulosic pulp on a dry weight basis of pulp. More preferably, the concentration of HAP is from about 0.05 pounds to about 5 pounds per ton of pulp, more preferably from 0.1 pounds to 1 pound. g. Other additives

The method of the present invention additionally includes conventional additives used in the amounts customary for their usual use. Suitable examples include: sizing agents, accelerators, strength agents, dye fixatives, polymeric coagulants, and the like. In addition, the produced paper can be surface treated with surface sizing agents or coating materials. 4. Compositions of the invention

A factor affecting the HAP concentration in the cellulose composition of the invention is the proportion of polymers added during the production process. The cellulosic composition of the present invention - which is preferably a cellulosic sheet, more preferably paperboard or paper - preferably comprises from about 0.01 to 10 lb/ton, more preferably from about 0.05 to 5 lb/ton, on a dry weight basis of the composition. ton, more preferably from about 0.1-1 lb/ton of HAP.

test part

The present invention is illustrated by the following steps and tests; these steps and tests are illustrative only and are not intended to limit the scope of the invention. All percentages, parts, etc., are by weight unless otherwise indicated. 1. Preparation of flocculant HAP of the present invention and comparative examples a. solution polymerization

The HAPs used in this invention, the anionic copolymers II, III, and V-VII, were prepared from acrylamide (AM), acrylic acid (AA), and lauryl acrylate (LA). Comparative polymers, anionic copolymers I and IV, were prepared without the hydrophobically modified monomer lauryl acrylate, ie from acrylamide and acrylic acid alone.

Polymers I-VII were all prepared by solution polymerization. The corresponding proportions of the monomers used in each case are listed below.

Table 1 Description of solution polymerization sample polymer monomer Raw material ratio (mol%) I (contrast) AA/AM 45/55 II AA/AM/LA 45/54/1 III AA/AM/LA 45/54/1 IV (comparison) AA/AM 30/70 V AA/AM/LA 30/69.5/0.5 VI AA/AM/LA 30/69/1 VII AA/AM/LA 30/68/2

In the case of polymers II and III, 2.75 parts of acrylamide, 0.17 parts (1 mole % monomer) of lauryl acrylate, 2.25 parts of acrylic acid, 1 part of non- A solution of ionic surfactant (Tergitol 15-S-9), and 100 parts deionized water was deoxygenated. Add 0.5 parts of 2 mg _KBrO3 solution and inject 10 parts of 0.03% _NaS2O5 via syringe pump over a period _of 60 minutes. Copolymers were obtained by precipitating the polymerization solution in acetone and dried under vacuum at 50°C overnight.

Polymers V, VI and VII were prepared in the same manner except for the different monomer ratios. For Polymer V, the monomer ratios were: 3.4 parts acrylamide, 0.1 part (0.5 mole % monomer) lauryl acrylate, and 1.5 parts acrylic acid. For Polymer VI, the monomer ratios were: 3.4 parts acrylamide, 0.19 parts (1 mole % monomer) lauryl acrylate, and 1.5 parts acrylic acid. For polymer VII, the monomer ratios were: 3.4 parts acrylamide, 0.38 parts (2 mole % monomer) lauryl acrylate, and 1.5 parts acrylic acid.

Polymer I was prepared using the same method and proportions as Polymers II and III, except that the lauryl acrylate was absent. Polymer IV was prepared by the same method as Polymer I, except that the monomer ratio of Polymer IV was: 3.5 parts of acrylamide and 1.5 parts of acrylic acid.

For each of polymers I, II, and III, the final dry product was redissolved in deionized water to produce 0.5% polymer solutions for viscosity characterization. b). Dispersion polymerization

Preparation of Hydrophobically Associating Polymers by Dispersion Polymerization.

Table 2 Saline dispersion sample description polymer monomer Raw material ratio (mol%) VIII (comparison) AA/AM 50/50 IX AA/AM/LMA 49.9/50/0.1 x AA/AM/LMA 49.8/50/0.2 XI AA/AM/LA 50/49.75/0.25 XII AA/AM/LA 50/49.5/0.5

LMA-lauryl methacrylate

LA-Lauryl Acrylate 1. Viscosity Characterization a). Solution Polymerization

The viscosity of each 0.5% solution was measured by a Brookfield viscometer at 12 rpm and room temperature. The results are listed in Table 3 below. Since they were prepared under essentially the same synthetic conditions, it was assumed that the molecular weights of HAP II and III, as well as that of non-associated polymer I, were the same. The 20-fold increase in the viscosity of the 0.5% solutions of HAP II and III compared to the Polymer I control sample is a qualitative indication of the incorporation of hydrophobic monomers in Polymers II and III. The excessively high 0.5% solution viscosities for polymers II and III also indicate that the HAPs of the invention are strongly associative in aqueous solution.

Table 3 Viscosity Characterization sample monomer 0.5% solution viscosity 1 (comparison) AA/AM 600 II AA/AM/LA 14,000 III AA/AM/LA 12,000

In addition, samples IV-VII were characterized for viscosity and rheology to demonstrate the associative properties of the modified samples compared to the unmodified comparative samples. The characterization is carried out with a 0.5% aqueous solution. As shown in Table 3 above, the Brookfield viscosity at 12 rpm was measured for each sample and the results showed that the apparent viscosity increased significantly with increasing hydrophobic value. The highest value of hydrophobicity will increase the Brookfield viscosity by a factor of 10 due to associative interactions. Additional studies were performed using a stress-controlled rheometer in conical and plate configurations (cone diameter 60 mm and fixed angle 2 degrees). Measuring the apparent viscosity of a 0.5% solids polymer sample at a constant shear rate of 10 sec ^-1 will yield similar results to a Brookfield viscometer where, at the highest hydrophobic value, the observed viscosity will increase to 10-fold, which indicates strong association properties. At a constant frequency of 1 Hz, and within a stress range of 0.1-10.0 Pa in the 20 logarithmic scale, a stress sweep was performed with the instrument in a dynamic stress oscillation mode. The G' storage modulus is specified as an equilibrium value in the linear viscoelastic region and is defined as:

G ¹ =(τ ₀ /γ ₀ )cosδ

where _τ0 is the stress amplitude, _γ0 is the maximum strain amplitude, and δ is the phase angle displacement between the stress and the final strain. The G' storage modulus is also known as the gel modulus, and is taken as an indication of the extent and strength of the network, as measured by intermolecular/intramolecular hydrophobic associations. Materials with higher G' values will undergo less strain or deformation when an equivalent stress is applied, and therefore, exhibit stronger gel complexes or networks. The data demonstrate a linear relationship between hydrophobic concentration and G' storage modulus, where the modulus increases with increasing degree of hydrophobicity and a high G' storage modulus is reached when hydrophobic substitution is at its highest. Unmodified polymer IV exhibited a storage modulus of 2 Pa, while modified polymer VII comprising 2 mol% lauryl acrylate exhibited a storage modulus of 25.6 Pa.

Subsequently, under a constant stress of 0.1 Pa, and within the frequency range of 0.0068 Hz to 10 Hz, using 3 readings per frequency decade, a dynamic oscillation mode frequency sweep was performed using the dynamic oscillation mode instrument. tanδ is the ratio of the loss (viscosity) modulus to the storage (elastic) modulus, determined by the following formula:

    tanδ = loss modulus/storage modulus = G″/G′

Materials with higher tan δ values will exhibit more viscous properties, while materials with lower tan δ values will exhibit more elastic properties. At low frequencies such as 0.0068 Hz, the stress rate on the specimen will allow the linear polymer to relax and exhibit a viscous type response, or higher tan delta. A polymer consisting of a chemical network or a physical network exhibits a primary structure of polymer chains. These reticulated materials are mechanically stable and do not relax over the time scale or frequency tested. These materials exhibit lower tan δ values and are therefore more elastic. As shown in Table 4, at 0.0068 Hz, a tan δ value of 20 was observed for the unmodified comparative polymer, while at the highest hydrophobic value a tan δ value of 0.224 was observed. In a broad frequency range up to 6.8 Hz, when lower tanδ values are observed, the degree of hydrophobic substitution is higher. This clearly demonstrates the strong association properties of HAP, which is consistent with the above viscosity data.

Table 4 Research on dynamic oscillation of controllable stress rheometer polymer monomer Raw material ratio (mol%) 0.5% solution viscosity mPas 0.5% solution viscosity mPas at shear rate = 10s ^-1 Stress scanning storage modulus G″Pa Frequency sweep tan δ, .0068Hz IV (comparison) AA/AM 30/70 650 1070 2 19.9 V AA/AM/LA 30/69.5/0.5 1700 2350 2.3 1.1 VI AA/AM/LA 30/69/1 8500 16400 12 0.363 VII AA/AM/LA 30.68/2 7000 10500 25.6 0.224 b). Dispersion polymerization

Dispersion polymers were characterized according to the same methods described for solution polymerized polymers. The data presented in Table 5 show similar results as for the solution polymerized products. An increase in the apparent viscosity of the 0.5% solution will be observed when hydrophobic monomers are introduced. Stress sweep studies in dynamic oscillatory mode showed that the G' storage modulus of samples IX and XI would increase when compared to the unmodified comparative sample VIII. Frequency-sweep studies in dynamic oscillatory mode indicated that hydrophobically associating polymers would have low tan δ values when compared to unmodified control samples.

Table 5 Research on dynamic oscillation of controllable stress rheometer polymer monomer Raw material ratio (mol%) charge density Shear rate = 10sec ^-1 0.5% solution viscosity mPas Stress scanning storage modulus G″Pa Frequency sweep tan δ, .0068Hz VIII (comparison) AM/AA 50/50 6.4 530 3.39 7.23 IX AM/AA/LMA 50/49.9/0.1 7.5 1230 10.9 0.92 x AM/AA/LMA 50/49.8/0.2 7.0 510 nonlinear n/a XI AA/AM/LA 50/49.75/0.25 7.6 1270 10.9 0.72 XII AA/AM/LA 50/49.5/0.5 7.3 410 nonlinear n/a

LA-lauryl acrylate

LMA-lauryl methacrylate

The viscosity properties of the diluted solutions of the HAP samples in Table 5 were measured in aqueous solutions of different NaCl concentrations, and compared with Polyflex CP.3, commercially available polyacrylamide retention aids (Cytec Industries, Inc., West Patterson, NJ) and Polymer E, A commercially available high MW anionic polyacrylamide flocculant was used for comparison. The data are presented in Table 5.1. As discussed in Introduction to Physical Polymer Science (LHSperling, Wiley Interscience, 1992), the properties of the dilute solution provide a corresponding indication of the molecular weight of the polymer. In this test, the solvent viscosity _η0 is compared with the viscosity η of the polymer solution. Relative viscosity is the unitless ratio of these two viscosities:

η _rel = η/η ₀

And the specific viscosity is the relative viscosity minus 1:

η _sp = η _rel -1

The reduced specific viscosity, referred to as RSV, is equal to the specific viscosity divided by the polymer concentration (C) expressed in grams per deciliter:

RSV＝η _sp /C

RSV has units of deciliters per gram (dL/g) and itself describes the hydrodynamic volume (HDV) of a polymer solution. Thus, a higher RSV indicates a larger solution HDV, and a higher MW when compared to conventional polymers. The test was carried out in a dilute state, so there was no overlap of any polymer windings. The RSV value can be determined by capillary or rotational viscometer methods by measuring the respective drain times or apparent viscosities of solvent and polymer solutions. The data described in Table 5.1 were measured using a Brookfield rotational viscometer equipped with an ultra-low (UL) adapter and capable of measuring the viscosity of low viscosity solutions. The data demonstrate the effect on polyelectrolyte RSV with varying salt concentration, which is well known to those of ordinary skill in the art. The HAP product of the invention showed a higher RSV in 1M NaCl additionally containing 0.1% nonylphenol ethoxylate (NPE) surfactant compared to a solution containing only M NaCl. This phenomenon, referred to as "RSV ratio," is a characteristic property of diluents of associative polymers containing hydrophobic groups and does not occur with linear, crosslinked, or branched polymers. A clear increase in the RSV ratio is observed with higher levels of hydrophobic monomer, which does not occur with the comparative polymers, Polyflex CP.3 or Polymer E. This phenomenon is well defined in the literature and is explained as the binding of the hydrophobic moiety to the surfactant, thus increasing the viscosity or RSV of the diluent.

Table 5.1 Dilution RSV Determination polymer monomer Raw material ratio RSV-DI water dL/g RSV-0.01MNaCl-dL/g RSV-1MNaCl-dL/g RSV-1MNaCl+0.1%NPE Ratio-1M NaCl: 1MNaCl+0.1%NPE VIII (comparison) AM/AA 50/50 730 113 twenty one twenty three 1.1 IX AM/AA/LMA 50/49.9/0.1 990 106 12 20 1.7 x AM/AA/LMA 50/49.8/0.2 700 twenty three 2 15 1.5 XI AA/AM/LA 50/49.75/0.25 930 128 16 twenty four 7.5 XII AA/AM/LA 50/49.5/0.5 650 34 4 17 4.3 Polyflex CP.3 AM/AA/ ^** 40/60/ ^** 580 47 13 13 1.0 Polymer E AM/AA 50/50 1216 184 44 44 1.0 [polymer concentration] dL/g .001 .005 .025 .025

LA-lauryl acrylate

LMA-lauryl methacrylate

^** NPE-Nonylphenol Ethoxylate Surfactant 1. Retention and Drainage Test

The first series of Britt Bottle Retention Test and Canadian Standard Freeness (CSF) Drainage Test were performed in order to compare the performance of the HAP of the present invention with the following materials: non-hydrophobic associative polymers; conventional anionic polypropylene amide flocculants; and inorganic and organic filter aids, commonly referred to in the industry as "microparticles" or "micropolymers".

The Britt bottle (Paper Research Materials, Inc., Gig Harbor, WA) retention assay is known in the art. In the Britt bottle retention test, a specified volume of an ingredient is mixed under dynamic conditions and an aliquot of the ingredient is filtered through the bottom screen of the bottle so that the retained fines can be quantified analyze. The Britt bottle used in this experiment was equipped with three vanes on the cylindrical wall for turbulent mixing and used a 76 micron screen in the bottom plate.

CSF apparatus (Lorentzen & Wettre, Code 30, Stockholm, Sweden) for measuring relative drainage or dehydration rates are also known in the art (TAPPE test procedure T227). The CSF unit consists of: a filter chamber and a rate measuring funnel, both mounted on a suitable support. The filter chamber is cylindrical with a perforated sieve plate and hinged plate at the bottom and a vacuum-tight hinged cover at the top. The rate measuring funnel is equipped with a bottom hole and an overflow hole in the side.

The CSF test is performed by placing 1 liter of ingredients (typically 0.30% consistency) in the filter chamber; closing the top cover; then immediately opening the bottom plate. The water is allowed to filter freely into the rate measuring funnel; water flow that exceeds the measurement in the bottom hole will overflow through the side hole and be collected in the graduated cylinder. The values obtained are in ml of filtrate. Higher amounts indicate higher dehydration rates.

The formulation used in this first series of tests was a synthetic alkaline formulation. The furnish is prepared from commercial dryboard pulps of hardwood and softwood, water and other materials. First, hardwood and softwood dryboard pulps were refined separately in a laboratory Valley beater (Voith, Appliton, WI). Then, these pulps are added to the aqueous medium.

The aqueous medium used in the preparation of the formulations contained: a mixture of locally hard water and deionized water of typical hardness. An amount of inorganic salt is added so as to provide this medium with a representative alkalinity and overall conductivity.

To prepare the furnish, the hardwoods and softwoods are dispersed in an aqueous medium in customary weight ratios. Precipitated calcium carbonate (PCC) was added to the furnish at a concentration of 25% by weight, based on pulp composite dry weight, to provide a final furnish comprising 80% fiber and 20% PCC filler.

This first series of experiments was conducted using: Polymer II, the inventive hydrophobically associated anionic polyacrylamide discussed herein; Polymer I, the unmodified anionic polyacrylamide comparative polymer discussed herein; Polymer E, a high MW commercially available anionic flocculant; Polyflex CP.3, a commercially available polyacrylamide filter aid (Cytec Indrstries, Inc., WestPatterson, NJ); and bentonite, also commonly used as a filter aid in the industry and retention aids.

The Britt bottle retention test in this series 2 was carried out using 500 ml of the synthetic formulation, typically at a concentration of 0.5% solids. The test was carried out in accordance with the procedure listed in Table 2 at a constant rpm speed according to the following parameters: Add starch, mix; Add alum, mix; Add polymer flocculant, mix; Add drainage aid, Mix; obtain a filtrate.

The cationic potato starch used was Stalok 600 (A.E. Staley, Decatur, IL) and the alum was aluminum sulfate octadecahydrate (Delta Chemical Company, Baltimore, MD) as a 50% solution. The cationic flocculant used (called CPAM-P) is 90/10 mole % acrylamide/N, NO dimethylaminoethyl acrylate quaternary chloromethane; the material is obtained from the market gets.

The retention values listed in Table 2 are the retention of fines where the total fines in the furnish was first determined by washing 500 ml of the furnish with 10 liters of water under mixing conditions to remove all fines, The fines are defined as particles smaller than the 76 micron mesh of the Britt bottle. Fines retention was then determined for each treatment by filtering 100 ml of the filtrate following the addition procedure; the filtrate was then filtered through a pre-weighed 1.5 μ filter paper. Calculate the retention rate of fine substances according to the following formula:

%fine matter retention rate=(filtrate wt-fine matter wt)/filtrate wt

Wherein the filtrate and fine material weights were normalized to 100 ml. Retention values are the average of two replicates.

A CSF drainage test was performed at a solids concentration of 0.30% using 1 liter of batch. The batches were prepared for the external processing according to the CSF unit; in square flasks using the same speed and mixing time as described for the Britt bottle test in order to provide turbulent mixing. After addition of additives and completion of the mixing procedure, the treated furnish was poured into the top of the CSF unit and tested as described.

In the Britt Bottle Retention Test and CSF Drainage Test, higher values indicate higher activity and a more desirable response.

The data presented in Table 6 illustrate the superior activity provided by the inventive polymer II when compared to the results obtained for the unmodified comparative polymer I and the conventional anionic flocculant polymer E. In addition, the polymers of the present invention provide an activity comparable to that of bentonite and similar to that of Polyflex CP.3. Unless otherwise stated, the dosages of the materials described are based on the product actives.

Table 6 ADD#1 Lbs./ton (active) ADD#2 Lbs./ton (active) polymer Lbs./ton (active) filter aid Lbs./ton (active) Average Retention % CSF mls Cationic Potato Starch 10 alum 5 none 0.5 none 0 27.29 395 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 none 0.75 48.43 380 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer II 0.75 69.54 620 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer I 0.75 50.46 535 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer E 0.75 53.16 540 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polyflex CP.3 0.75 77.85 650 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Bentolite HS 4 64.72 600

A series of retention and drainage tests were performed using a Pulse Drainage Device (PDD). The test substances, test conditions, and corresponding chemical additives are the same as those used in Table 6.

The PDD is equipped with rotating hydrofoils, and a vacuum volume below the screen. It is an in-house developed instrument (described in US 5,314,581) as a suitable simulation of actual retention, drainage, and sheet forming operations. During the test run, vacuum was applied to the fiber slurry to aid in the formation of the fiber mat, and vacuum was continued until a steady state equilibrium vacuum was reached.

There are many kinds of measurements that can be made using the PDD. For example, PDD can be used to measure first-pass retention, peak vacuum, equilibrium vacuum, peak-to-equilibrium vacuum ratio (PEVR), and vacuum drain time.

First pass fines retention was measured by a mass balance calculation that included the weight of the final sheet, the total mass introduced into the PDD, and the total fines fraction of the stock, defined as a particle size less than 76 μ the slurry part. As with Britt bottle fines retention, higher retention values indicate a desired response.

Peak vacuum is the total vacuum required during batt formation until air is drawn through the formed batt, then vacuum is interrupted. Equilibrium vacuum is the steady state vacuum drawn through the formed sheet. Both peak vacuum and equilibrium vacuum are measured in inches of mercury. For peak vacuum, lower values indicate easier dewatering of the fibrous substrate.

The Peak to Equilibrium Vacuum Ratio (PEVR) is the unitless ratio of these two output values. Studies have shown that this parameter can be used as an indicator of formation, with lower PEVR values indicating more desirable or uniform formation.

Vacuum filtration time is the time to peak vacuum and is measured by the instrument in seconds. This response is believed to be analogous to the wet line on a paper machine, which is the point at which moisture has been removed sufficiently that the sheet loses its gloss or free water is visible. The wet line position is usually monitored as an indication of machine drainage. For the vacuum drainage parameter, the desired response is a reduced (low) value, indicating improved drainage.

A second series of drainage tests was performed using PDD using the same filter aid as the first series of tests, except without bentonite. Associative starch, alum, and cationic flocculants are as previously described. The results in Table 7 list the measured values obtained from the above measurements performed by PDD.

These results show that polymer II of the present invention provides a defined drainage dose response. Specifically, gravity drainage, peak vacuum, and vacuum drainage time improved as the dose was increased.

It should be noted that there was no dose response for the unmodified comparative polymer I and the conventional flocculant polymer E. Therefore, retention and corresponding drainage response either did not increase or decreased when the dosage of these polymers was increased.

The improved drainage activity of Polymer II is also clearly demonstrated by the data in Table 7 when compared to Comparative Polymer I and Polymer E. Polymer II provides a higher retention rate of fine matter than Polyflex CP.3, and similar water filtration activity to Polyflex CP.3; for example, 1.0 lb/ton of Polymer II provides about 0.5 lb/ton of water filtration activity t Polyflex CP.3 equivalent. It should be noted that Polymer II provided lower PEVR values than Polyflex CP.3 at the same drainage time, which is an indication of improved sheet uniformity or formation.

Table 7 10Lbs./Ton cationic potato starch+5Lbs./Ton aluminum sulfate+0.5Lbs./TonCPAM-P flocculant Dose (Lbs./T) First pass fine material retention % Gravity filtration time-seconds Equilibrium vacuum (Hg) Peak vacuum (Hg) Peak to Equilibrium Vacuum Ratio Vacuum water filtration time-seconds No filter aid 0 89.90% 3.25 3.61 5.15 1.43 1.028 Polyflex CP.3 0.5 93.47% 3.04 2.97 4.44 1.49 0.679 Polyflex CP.3 0.75 95.10% 2.99 2.71 4.07 1.50 0.622 Polyflex CP.3 0.5 95.37% 3.01 2.65 4.01 1.51 0.608 Polymer I 0.75 92.34% 3.16 3.53 4.88 1.38 0.798 Polymer I 1 91.34% 3.18 3.53 4.81 1.36 0.801 Polymer I 0.5 94.74 3.13 3.52 4.81 1.37 0.778 Polymer II 0.5 %96.05% 3.09 3.27 4.66 1.42 0.731 Polymer II 0.75 95.83% 3.05 3.10 4.53 1.46 0.685 Polymer II 1 95.64% 2.91 3.01 4.43 1.47 0.673 Polymer E 0.5 93.31% 3.14 3.50 4.81 1.37 0.793 Polymer E 0.75 92.20% 3.18 3.43 4.78 1.39 0.786 Polymer E 1 94.21 4.67 3.43 4.73 1.41 0.792

A series of Britt bottle retention and CSF tests were performed using: Polymer III, the hydrophobically associated anionic polyacrylamide of the invention discussed herein; Polymers V-VII, the hydrophobically associated polymers of the invention Polymers with sequentially increasing hydrophobic modification values; Polymer IV, the unmodified anionic polyacrylamide comparative polymer discussed here; Polymer E; and Polyflex CP.3. These tests were performed according to the methods previously described. The data demonstrate the superior activity of the invention provided by Polymer III and Polymer VII when compared to the unmodified comparative Polymer IV. As the degree of hydrophobic substitution increases, an increased retention and drainage activity will be observed, where the activity of Polymer VII is similar to that of Polyflex CP.3. The data are listed in Table 8.

Table 8 Add#1 Lbs./ton (active) Add#2 Lbs./ton (active) Add#3 Lbs./ton (active) filter aid Lbs./ton (active) Average Retention % CSF Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 none 0. 51.1 100 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polyflex CP.3 0.75 77.5 640 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer E 0.75 19.5 530 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 Polymer IV 0.75 12.0 510 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 Polymer V 0.75 12.4 505 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 Polymer VI 0.75 55.1 545 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer VII 0.75 66.3 585 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer III 0.75 69.0 610

Using PDD, another series of retention and drainage tests was performed as in the second series. The test conditions and materials were the same as those used in the previous series except that the filter aids were the following materials: Polymer III and Polyflex CP.3 of the invention discussed here; Polymer M, a commercially available high MW polyacrylamide flocculants; and bentonite.

Polymeric materials were evaluated at 0.5, 0.75, and 1.0 lb/ton of active polymer at commonly used mill dosage levels, while bentonite was evaluated at 2, 4, and 6 lb/ton . The results are listed in Table 9.

The data in Table 9 illustrate the activity of the polymers of the invention. Polyflex CP.3, bentonite, and Polymer III all showed positive dose-response activity, while Polymer M was not dose-active. Polymer III provides comparable to greater retention and drainage activity than bentonite.

With respect to the comparative activities listed in Table 9, Polymer M provided equivalent retention and drainage to Polymer III, but significantly higher PEVR values; this sheet uniformity/formation at comparable drainage A reduction of will be undesirable. The water filtration activity of Polymer III is similar to that of Polyflex CP.3. For example, 1.0 lb/ton Polymer III provides about the same water filtration activity as 0.5 lb/ton Polyflex CP.3. It should also be noted that the inventive Polymer III provides lower PEVR values than Polyflex CP.3 at the same drainage time, said values being indicative of improved sheet uniformity or formation.

Table 9 10Lbs./Ton cationic potato starch+5Lbs./Ton aluminum sulfate+5Lbs./TonCPAM-P flocculant+filter aid Dose (Lbs./T) First pass fine material retention Gravity filtration time-seconds Equilibrium vacuum (Hg) Peak vacuum (Hg) Peak to Equilibrium Vacuum Ratio Vacuum water filtration time-seconds none 0 87.61% 3.37 3.42 4.97 1.455 0.880 Polyflex CP.3 0.5 96.42% 3.17 2.77 4.05 1.465 0.627 Polyflex CP.3 0.75 98.81% 3.30 2.61 3.84 1.472 0.577 Polyflex CP.3 1 97.65% 3.18 2.49 3.70 1.486 0.515 Polymer III 0.5 95.39% 3.28 3.00 4.32 1.440 0.672 Polymer III 0.75 86.26% 3.09 2.98 4.29 1.442 0.662 Polymer III 1 95.54% 3.09 2.91 4.22 1.451 0.649 Polymer M 0.5 95.27% 3.32 2.91 4.33 1.787 0.662 Polymer M 0.75 95.80% 3.22 2.74 4.18 1.523 0.649 Polymer M 1 96.23% 3.38 2.71 4.29 1.583 0.651 Bentonite 2 89.95% 3.32 3.25 4.51 1.391 0.724 Bentonite 4 93.96% 3.11 3.08 4.38 1.420 0.678 Bentonite 6 96.47% 4.16 2.96 4.21 1.423 0.649

Another series of Britt bottle retention and CSF drainage tests were performed using Polymer III and Polyflex CP.3 using more CPAM-P flocculant and an additional flocculant, polyvinylamine (PVAm). PVAm is produced by aqueous polymerization of N-vinylformamide monomer followed by hydrolysis of the polymer to produce N-vinylamine. The subject polymer was 90% hydrolyzed, resulting in a final copolymer of 90 mol% N-vinylamine/10 mol% N-vinylformamide; the polymer had a solids content of 5% and exhibited The intrinsic viscosity is 3dL/g. The data in Table 10 demonstrate the activity using HAP at higher levels of CPAM-P flocculant, as well as with PVAm flocculant.

Table 10 Add#1 Lbs.ton (active) Add#2 Lbs.ton (active) Add#3 Lbs.ton (active) filter aid Lbs./ton (active) Average Retention % CSF Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 none 0 53.6 370 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polyflex CP.3 0.75 78.6 650 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 0.5 Polymer III 0.75 70.8 595 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 none 0 66.6 395 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 Polyflex CP.3 0.75 91.6 680 Cationic Potato Starch 10 Alum 5 CPAM-P flocculant 1 Polymer III 0.75 80.9 610 Cationic Potato Starch 10 Alum 5 PV Am flocculant 0.5 none 0 35.9 435 Cationic Potato Starch 10 Alum 5 PV Am flocculant 0.5 Polyflex CP.3 0.75 91.1 730 Cationic Potato Starch 10 Alum 5 PV Am flocculant 0.5 Polymer III 0.75 74.0 665

Using Polymer III, Polyflex CP.3, and two additional Polyflex products, namely Polyflex CS and Polyflex CP.2 (also available from Cytec Industries, Inc), another series was carried out as described in Table 11 under the preceding procedure. PDD test. The data in Table 11 show that Polymer III of the present invention provides improved retention and drainage activity when compared to Polyflex CP.2, comparable activity to Polyflkex CS, and similar activity to Polyflex CP.3 .

Table 11 10 Lbs./Ton cationic potato starch+0.5Lbs./TonCPAM-P flocculant+filter aid Lbs./ton (active) First pass fine material retention % Gravity filtration time-seconds Equilibrium vacuum (Hg) Peak vacuum (Hg) Ratio of peak to equilibrium vacuum Vacuum water filtration time-seconds No filter aid 0 85.2% 3.44 3.61 5.41 1.50 1.15 Polyflex CP.3 0.5 92.6% 3.12 2.77 4.28 1.55 0.64 Polyflex CP.3 0.75 94.1% 3.09 2.52 3.97 1.58 0.55 Polyflex CP.3 1 93.5% 3.00 2.44 3.97 1.55 0.54 Polyflex CS 0.5 91.6% 3.00 3.20 4.75 1.48 0.75 Polyflex CS 0.75 92.8% 3.12 3.07 4.61 1.50 0.72 Polyflex CS 1 95.9% 3.13 2.92 4.47 1.53 0.67 Polyflex CP.2 0.5 91.6% 3.20 3.33 4.78 1.43 0.75 Polyflex CP.2 0.75 92.7% 3.16 3.27 4.73 1.45 0.77 Polyflex CP.2 1 91.2% 3.27 3.29 4.75 1.40 0.75 Polymer III 0.5 89.5% 3.35 3.30 4.77 1.44 0.80 Polymer III 0.75 94.0% 3.11 3.07 4.64 1.51 0.73 Polymer III 1.00 94.3% 3.13 3.01 4.57 1.52 0.68 Polymer E 0.5 91.9% 3.14 2.97 4.60 1.55 0.70 Polymer E 0.75 95.4% 3.08 2.75 4.54 1.65 0.70 Polymer E 1 92.9% 3.20 2.66 4.60 1.73 0.75

Another series of Britt bottle retention and CSF drainage studies were performed using the aforementioned saline dispersible polymer. The studies listed in Table 12 were carried out using the following polymers: Polymers IX and X, polymers of the inventive process modified with lauryl methacrylate; Polymers XI and XII, polymers of the present invention modified with lauryl acrylate. Polymers of the inventive process; Polymer VIII is a comparative polymer produced under conditions comparable to hydrophobically associated polymers, but containing no hydrophobic substituents; Polyflex CP.3, and Polymer A, a conventional high MW anionic polyacrylamide powder flocculant. The test conditions and corresponding additives are as described above, except that the cationic flocculant used is CPAM-N; the material is equivalent to the previously used CPAM-P in terms of composition and physical form. Anionic polyacrylamide flocculant (APAM) is also used. This material is a 30 mole % sodium acrylate/70 mole % acrylamide copolymer, commercially available as a self-reversing emulsion. The data in Table 12 demonstrate the improved activity of the materials of the invention. Polymers IX and XI showed high retention and drainage activity when compared to commercial drainage aid bentonite, comparative polymer VIII, and conventional flocculant polymer A. This improved activity was observed when used with CPAM flocculant, with APAM flocculant, and without flocculant.

Table 12 Add#1 Lbs/ton(activity) Add#2 Lbs/ton(activity) Add#3 Lbs/ton(activity) filter aid Lbs/ton(activity) Average Retention % CSF Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 none 0 53.6 370 Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 Polymer VIII 0.75 71.1 620 Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 Polymer IX 0.75 78.9 650 Cationic Potato Starch 10 Alum 5 CPAM-P 1 Polymer XI 0.75 76.4 640 Cationic Potato Starch 10 Alum 5 CPAM-P 1 PolymerX 0.75 73.1 630 Cationic Potato Starch 10 Alum 5 CPAM-P 1 Polymer XII 0.75 555 Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 Polyflex CP.3 0.75 86.0 680 Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 Polymer A 0.75 68.1 620 Cationic Potato Starch 10 Alum 5 CPAM-P 0.5 Bentolite HS 4 70.7 630 Cationic Potato Starch 10 Alum 5 none 0 Polymer VIII 0.5 59.6 560 Cationic Potato Starch 10 Alum 5 none 0 Polymer IX 0.5 66.0 545 Cationic Potato Starch 10 Alum 5 none 0 Polymer XI 0.5 67.8 555 Cationic Potato Starch 10 Alum 5 none 0 PolymerX 0.5 52.0 495 Cationic Potato Starch 10 Alum 5 none 0 Polymer XII 0.5 435 Cationic Potato Starch 10 Alum 5 none 0 Polyflex CP.3 0.5 71.5 585 Cationic Potato Starch 10 Alum 5 none 0 Polymer A 0.5 57.1 560 Cationic Potato Starch 10 Alum 5 APAM 0 Polymer VIII 0.5 530 Cationic Potato Starch 10 Alum 5 APAM 0 Polymer IX 0.5 565 Cationic Potato Starch 10 Alum 5 APAM 0 Polymer XI 0.5 540 Cationic Potato Starch 10 Alum 5 APAM 0 PolymerX 0.5 540 Cationic Potato Starch 10 Alum 5 APAM 0 Polymer XII 0.5 520 Cationic Potato Starch 10 Alum 5 APAM 0 Polyflex CP.3 0.5 630 Cationic Potato Starch 10 Alum 5 APAM 0 Polymer A 0.5 505

A series of evaluations were performed on the PDD using comparable methods as described in Table 12. The studies listed in Table 13 were carried out with the following polymers: Polymers IX and X, polymers of the inventive process modified with lauryl methacrylate; Polymers XI and XII, inventive modified with lauryl acrylate Polymer VII is a comparative polymer produced under conditions comparable to the hydrophobically associating polymer, but containing no hydrophobic substituents; and Polyflex CP.3. The data in Table 13 demonstrate positive drainage activity for Polymers IX, X, and XI when compared to the unmodified Comparative Polymer VIII. Polymers IX, X, and XI also indicated a positive dose response at low PEVR, whereas the unmodified comparative polymer did not have a significant dose response.

Table 13 10 Lbs./Ton cationic potato starch+0.5Lbs./TonCPAM-P flocculant+filter aid Lbs./ton (active) First pass fine material retention % Gravity filtration time-seconds Equilibrium vacuum (Hg) Peak vacuum (Hg) Ratio of peak to equilibrium vacuum Vacuum water filtration time-seconds none 86.1% 3.98 3.33 5.11 1.53 0.94 Polymer VIII 0.5 93.1% 3.76 2.89 4.38 1.52 0.67 Polymer VIII 1 95.6% 3.79 2.72 4.18 1.54 0.63 Polymer IX 0.5 93.7% 3.71 2.77 4.12 1.49 0.64 Polymer IX 1 94.5% 3.64 2.51 3.75 1.50 0.54 PolymerX 0.5 92.5% 3.69 2.79 4.12 1.48 0.65 PolymerX 1 97.2% 3.66 2.48 3.72 1.50 0.55 Polymer XI 0.5 94.0% 3.65 2.74 4.07 1.49 0.62 Polymer XI 1 93.7% 3.68 2.49 3.87 1.55 0.54 Polymer XII 0.5 86.0% 3.86 3.23 4.69 1.45 0.77 Polymer XII 1 89.1% 3.73 3.00 4.43 1.47 0.71 Polyflex CP.3 0.5 95.8% 3.70 2.60 3.93 1.51 0.57 Polyflex CP.3 1 94.9% 3.55 2.29 3.52 1.54 0.49

It should be pointed out that the foregoing embodiments are only for illustration, and in no way constitute a limitation to the scope of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration only, not words of limitation. Various changes may be made within the purview of the appended claims without departing from the scope and spirit of the invention. Although the invention has been described with reference to particular instrumentalities, materials and embodiments, the invention is not limited to the particular cases disclosed herein; the invention extends to all functionally equivalent structures, methods and uses, which fall within the within the scope of the appended claims.

Claims (37)

1. A process for the preparation of a cellulosic fiber composition comprising adding a hydrophobically associated polymer to a cellulosic slurry, said polymer being composed of at least one hydrophobic olefinic non- Repeating units of saturated monomers and at least one repeating unit selected from nonionic ethylenically unsaturated monomers, cationic ethylenically unsaturated monomers, or anionic ethylenically unsaturated monomers, provided that the at least one A hydrophobic ethylenically unsaturated monomer free of 2,4,6-tribenzoethylbenzene. 2. The method of claim 1, wherein the hydrophobic ethylenically unsaturated monomer comprises: an ethylenically unsaturated monomer having at least one pendant hydrophobic group. 3. The method of claim 2, wherein the hydrophobic side group is selected from: one or more C ₄ -C ₂₀ alkyl groups, C ₄ -C ₂₀ cycloalkyl groups, polynuclear aromatic hydrocarbon groups, wherein the alkyl group contains one or more an alkaryl group of four or more carbons; a haloalkyl group of four or more carbons, or a polyalkyleneoxy group. 4. The method of claim 3, wherein the hydrophobic group is selected from one or more _C4 - _C20 alkyl groups. 5. The method of claim 3, wherein the hydrophobic group is selected from one or more _C8 - _C20 alkyl groups. 6. The method of claim 1, wherein the hydrophobic ethylenically unsaturated monomer is selected from the group consisting of one or more hydrocarbon esters of ethylenically unsaturated carboxylic acids and their salts. 7. The method of claim 1, wherein the hydrophobic ethylenically unsaturated monomer is selected from one or more _C10 - _C20 alkyl esters of propylene and methacrylate. 8. The method of claim 1, wherein the nonionic ethylenically unsaturated monomer is selected from one or more of the following: acrylamide, methacrylamide, N-alkylacrylamide, N,N-dioxane Acrylamide, methyl acrylate, methyl methacrylate, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, or N-vinylpyrrolidone. 9. The method of claim 8, wherein the N-alkylacrylamide is N-methacrylamide. 10. The preparation method of the cellulose fiber composition of claim 8, wherein, said at least one nonionic ethylenically unsaturated monomer is selected from one or more of the following substances: acrylamide, methacrylamide, or N-alkylacrylamides. 11. The method of making a cellulosic fiber composition according to claim 8, wherein said at least one nonionic ethylenically unsaturated monomer is acrylamide. 12. The method for preparing the cellulose fiber composition of claim 1, wherein said at least one anionic ethylenically unsaturated monomer is selected from one or more of the following substances: acrylic acid, methacrylic acid, 2-propylene Amido-2-methylpropanesulfonate, sulfoethyl(meth)acrylate, vinylsulfonic acid, styrenesulfonic acid, maleic acid or salts thereof. 13. The method for preparing the cellulose fiber composition according to claim 12, wherein said at least one anionic ethylenically unsaturated monomer is selected from one or more of the following substances: acrylic acid, methacrylic acid or their salts . 14. The method for preparing a cellulose fiber composition according to claim 13, wherein said at least one anionic ethylenically unsaturated monomer is selected from one or more of sodium salt or ammonium salt of acrylic acid. 15. The method of making the cellulosic fiber composition of claim 1, wherein said at least one hydrophobic ethylenically unsaturated monomer is present in an amount of from about 0.01 mole percent to about 1 mole percent. 16. A process for the preparation of a cellulosic fiber composition comprising adding a water-soluble hydrophobically associated polymer to a cellulosic slurry, said polymer comprising: repeating units of at least one hydrophobic ethylenically unsaturated monomer from about 0.001 mole % to about 10 mole % and selected from one or more C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid; Repeat units of at least one nonionic ethylenically unsaturated monomer selected from one or more of the following: acrylamide, methacrylamide, N-alkylacrylamide , N,N-dialkylacrylamide, methyl acrylate, methyl methacrylate, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, or N-ethylene Base pyrrolidone; Repeat units of at least one anionic ethylenically unsaturated monomer selected from one or more of the following: acrylic acid, methacrylic acid, 2-acrylamido-2-methyl Propanesulfonate, sulfoethyl(meth)acrylate, vinylsulfonic acid, styrenesulfonic acid, maleic acid or their salts. 17. The preparation method of the cellulosic fiber composition of claim 16, wherein, water-soluble hydrophobic association polymer comprises: repeating units of at least one hydrophobic ethylenically unsaturated monomer from about 0.001 mole % to about 10 mole % and selected from one or more C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid; Repeating units of one or more nonionic ethylenically unsaturated monomers selected from acrylamide, methacrylamide, N-alkylacrylamide; A repeating unit of at least one anionic ethylenically unsaturated monomer selected from one or more of acrylic acid, methacrylic acid, or their salts. 18. A method for preparing a cellulose fiber composition, comprising adding a water-soluble hydrophobically associated anionic polymer to a cellulose slurry, said polymer comprising: selected from lauryl acrylate or lauryl methacrylate, acrylamide , and one or more hydrophobic ethylenically unsaturated monomers of acrylic acid. 19. The method of claim 18, wherein the hydrophobic ethylenically unsaturated monomer is lauryl acrylate. 20. The method of claim 18, wherein the hydrophobic ethylenically unsaturated monomer is lauryl methacrylate. 21. A cellulose fiber composition comprising cellulose pulp and an aqueous slurry of a water-soluble hydrophobically associating polymer, wherein the polymer comprises: from about 0.001 mole percent to about 10 mole percent of repeat units of at least one hydrophobic ethylenically unsaturated monomer, and at least one repeating unit selected from nonionic ethylenically unsaturated monomers, cationic ethylenically unsaturated monomers, or anionic ethylenically unsaturated monomers, The prerequisite is that said at least one hydrophobic ethylenically unsaturated monomer does not contain 2,4,6-tritenethylbenzene. 22. The cellulosic fiber composition of claim 21, wherein the at least one hydrophobic ethylenically unsaturated monomer comprises: an ethylenically unsaturated monomer having at least one pendant hydrophobic group. 23. The cellulose fiber composition of claim 22, wherein said hydrophobic side group is selected from one or more of the following groups: C ₄ -C ₂₀ alkyl, C ₄ -C ₂₀ cycloalkyl, polynuclear aromatic A hydrocarbyl group, an alkaryl group in which the alkyl group contains one or more carbons; a haloalkyl group of four or more carbons, or a polyalkyleneoxy group. 24. The cellulosic fiber composition of claim 23, wherein at least one hydrophobic group is selected from one or more _C4 - _C20 alkyl groups. 25. The cellulosic fiber composition of claim 24, wherein at least _{one hydrophobic group is selected from one or more C8-C20 alkyl} groups. 26. The cellulosic fiber composition of claim 21, wherein the at least one hydrophobic ethylenically unsaturated monomer is selected from the group consisting of one or more hydrocarbon esters of ethylenically unsaturated carboxylic acids and their salts. 27. The cellulosic fiber composition of claim 26, wherein at least one hydrophobic ethylenically unsaturated monomer is selected from one or more _C10 - _C20 alkyl esters of acrylic and methacrylic acid. 28. The cellulosic fiber composition of claim 21, wherein at least one nonionic ethylenically unsaturated monomer is selected from one or more of the following: acrylamide, methacrylamide, N-alkylacrylamide, N,N dialkylacrylamide, methyl acrylate, methyl methacrylate, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, or N-vinylpyrrolidone . 29. The cellulosic fiber composition of claim 28, wherein at least one nonionic ethylenically unsaturated monomer is acrylamide. 30. The cellulosic fiber composition of claim 21, wherein said at least one anionic ethylenically unsaturated monomer is selected from one or more of the following: acrylic acid, methacrylic acid, 2-acrylamido-2 - Methylpropanesulfonate, sulfoethyl(meth)acrylate, vinylsulfonic acid, styrenesulfonic acid, maleic acid or salts thereof. 31. The cellulosic fiber composition of claim 30, wherein the at least one anionic ethylenically unsaturated monomer is selected from one or more sodium or ammonium salts of acrylic acid. 32. The cellulosic fiber composition of claim 21, wherein the at least one hydrophobic ethylenically unsaturated monomer group is present in an amount from about 0.01 mole percent to about 1 mole percent. 33. A cellulose fiber composition comprising cellulose pulp and an aqueous slurry of a water-soluble hydrophobically associating polymer, wherein the polymer comprises: repeating units of at least one hydrophobic ethylenically unsaturated monomer from about 0.001 mole % to about 10 mole % and selected from one or more C ₁₀ -C ₂₀ alkyl esters of acrylic acid and methacrylic acid; Repeat units of at least one nonionic ethylenically unsaturated monomer selected from one or more of the following: acrylamide, methacrylamide, N-alkylacrylamide , N,N dialkylacrylamide, methyl acrylate, methyl methacrylate, acrylonitrile, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, or N-vinyl pyrrolidone; Repeat units of at least one anionic ethylenically unsaturated monomer selected from one or more of the following: acrylic acid, methacrylic acid, 2-acrylamido-2-methyl Propanesulfonate, sulfoethyl(meth)acrylate, vinylsulfonic acid, styrenesulfonic acid, maleic acid or their salts. 34. The cellulosic fiber composition of claim 33, wherein the water-soluble hydrophobically associating polymer comprises: at least one hydrophobic ethylenically unsaturated monomer selected from one or more lauryl acrylates or lauryl methacrylates, at least one nonionic ethylenically unsaturated monomer is acrylamide, The at least one anionic ethylenically unsaturated monomer is selected from one or more sodium or ammonium salts of acrylic acid. 35. Paper comprising the cellulosic sheet of claim 33. 36. A cellulose fiber composition comprising cellulose pulp and an aqueous slurry of a water-soluble hydrophobically associating polymer, wherein the polymer comprises: repeating units selected from one or more hydrophobic ethylenically unsaturated monomers of lauryl acrylate or lauryl methacrylate, The repeating unit of the nonionic ethylenically unsaturated monomer is acrylamide, The repeating unit of the anionic ethylenically unsaturated monomer is acrylic acid. 37. The cellulosic fiber composition of claim 36 in the form of paper.