MXPA05006023A - Cationic or amphoteric copolymers prepared in an inverse emulsion matrix and their use in preparing cellulosic fiber compositions. - Google Patents

Abstract

A papermaking method and a composition which utilize, as a drainage aid, a water-soluble cationic or amphoteric copolymer prepared via a water-in-oil polymerization technique that, absent a cross-linking agent, is characterized by a Huggins' constant (k') determined in 0.01 M NaCl greater than 0.3 and a storage modulus (G') at 6.3 Hz greater than 50 Pa.

Description

CATIÓNICOS OR ANFOTÉRICOS COPOLYMERS PREPARED IN A MATRIX OF REVERSE EMULSION AND ITS USE IN THE PREPARATION OF COMPOSITIONS OF CELLULOSE FIBER FIELD OF THE INVENTION The present invention relates to water-soluble cationic and amphoteric copolymers obtained by inverse emulsion polymerization and their use in the preparation of cellulosic fiber compositions. The present invention further relates to cellulosic fiber compositions, such as paper and paperboard, which incorporate water-soluble cationic and amphoteric copolymers.

BACKGROUND OF THE INVENTION The making of sheets of cellulosic fiber, particularly paper and cardboard, includes the following: 1) producing an aqueous slurry of cellulosic fiber; which may also contain extenders or inorganic mineral pigments; 2) deposit this slurry on a wire or cloth for making moving paper; and 3) forming a sheet of the solid components of the slurry by draining the water. The above is continued by pressing and drying the sheet in additional water removed. Organic and inorganic chemicals are sometimes added to the slurry prior to the sheeting step to make the papermaking method less expensive, faster and / or achieve specific properties in the final paper product. The paper industry continually strives to improve paper quality, increase productivity and reduce manufacturing costs. Chemicals are sometimes added to the fibrous slurry before reaching the wire or papermaking fabric, to improve the drainage / desiccation of the paper machine and the retention of solids; These chemicals are called retention and / or drainage aids. As for the improvement of drainage / desiccation, the draining or desiccation of the fibrous slurry in the wire or papermaking fabric sometimes limits the stage of achieving faster paper machine speeds. Improved desiccation can also result in a drying sheet in the press and drying sections, resulting in reduced energy consumption. In addition, this is the stage in the papermaking method that determines many final properties of the sheet. With respect to the retention of solids, retention aids for papermaking are used to increase the retention of solids from fine raw materials in the web during the turbulent method of draining and forming the web. Without adequate retention of fine solids, they are from any loss in mill effluent or accumulation at high levels in the recirculating white water cycle, potentially causing deposit buildup. Additionally, insufficient retention increases the cost of papermaking due to the loss of additives intended to be absorbed in the fiber to provide the respective opacity, strength or paper size properties. Water soluble polymers of high molecular weight (MW) with any cationic or amphoteric charge have traditionally been used as retention and drainage aids. The recent development of inorganic microparticles, known as retention and drainage adjuvants, in combination with high MW water soluble polymers, have shown superior retention and drainage efficiency compared to conventional high MW water soluble polymers. U.S. Patent Nos. 4,294,885 and 4,388,150 teach the use of starch polymers with colloidal silica. U.S. Patent No. 4,753,710 teaches the flocculation of pulp feedstocks with a high MW cationic flocculant, inducing wear on flocculated raw materials, and then introducing bentonite clay into the raw materials. U.S. Patent Nos. 5,274,055 and 5,167,766 describe the use of chemically crosslinked organic micro-polymers as retention and drainage aids in the papermaking process. Copolymers have also been used to control the deposition of contaminants or organic deposits in paper making systems. Organic deposits is a term used to describe sticky materials, insoluble in water in the papermaking system that are harmful in the production of paper. Such materials derived from these trees during the pulping process and for papermaking are referred to as resin or wood resin, while the term sticky is used to describe contaminants that are derived from adhesives or coatings introduced into the papermaking process as a recycled fiber contaminant. One strategy for removing these materials is to agglomerate the organic deposits into larger, non-sticky particles that can be removed from the papermaking material or incorporated in the sheet without causing deposits in the papermaking system of sheet defects. Chemicals that are able to interact with organic deposits and mitigate their negative impact include surfactants and polymers. The polymers can be ionic or non-ionic, and include materials used as flocculants, coagulants and dispersants. The effectiveness of the polymers or copolymers used will vary depending on the type of monomers of which they are composed, the arrangement of the monomers in the polymer matrix, the molecular weight of the synthesized molecule, and the method of preparation. The last feature is an approach of the present invention. Specifically, it has been unexpectedly disclosed that cationic and amphoteric water soluble copolymers when prepared under certain conditions exhibit unique physical characteristics. Additionally, the copolymers provide unanticipated activity in certain applications including papermaking applications such as retention and drainage aids and contaminant control adjuvants. Although the synthesis methods employed are generally known to those skilled in the art, there is no prior art that suggests that the unique physical characteristics and the observed inanticipated activity should result.

SUMMARY OF THE INVENTION The present invention is directed to water-soluble cationic and amphoteric copolymers and cellulosic fiber compositions containing the copolymer, particularly a cellulosic sheet such as paper or paperboard. The invention is also directed to a method for making the copolymer and cellulosic fiber compositions. In another aspect, the present invention provides a method for making a cellulosic fiber composition comprising adding, to a cellulose pulp slurry, a water soluble cationic or amphoteric copolymer of the following Formula I or Formula II. The invention further relates to cellulosic fiber compositions, which include an aqueous suspension of cellulose pulp, which contains such cationic or amphoteric water soluble copolymers. As used herein, the term "copolymer" is understood to be polymer compositions consisting of two or more different monomer units. In accordance with the present invention, it has been unexpectedly disclosed that certain cationic and amphoteric copolymers show unique physical characteristics and provide in-anticipated activity when prepared using certain polymerization conditions. The cationic and amphoteric copolymers of the invention are obtained by inverse emulsion polymerization (water-oil). For cationic copolymers one or more water-soluble monomers, in particular, one or more cationic monomers are used in the emulsion polymerization. For amphoteric copolymers one or more cationic monomers and one or more anionic monomers are used in the emulsion polymerization. The resulting cationic and amphoteric copolymers are soluble in water. The cationic copolymers of the invention have the formula: [-B-co-C -] - (Formula I) wherein B is a non-ionic polymer segment formed from the polymerization of one or more non-ionic monomers; C is a segment of cationic polymer formed from the polymerization of one or more cationic ethylenically unsaturated monomers; the% molar ratio B: C is from 1:99 to 99: 1; and "co" is a designation for a polymer system with an unspecified arrangement of two or more monomer components. In addition, the preparation is conducted in one form, the absent crosslinked agents and by a water-in-oil emulsion procedure, so that the Huggins constant (k ') determined at 0.01 M NaCl is greater than 0.5 and the storage module (G ') for 3.0% by weight which activates the polymer solution at 6.3 Hz is greater than 50 Pa. The amphoteric copolymers of the invention have the formula: [-B-co-C-co-A- ] - (Formula II) wherein B is a nonionic polymer segment formed from the polymerization of one or more non-ionic monomers; C is a segment of cationic polymer formed from the polymerization of one or more cationic ethylenically unsaturated monomers; ? is an anionic polymer segment formed from the polymerization of one or more ethically unsaturated anionic monomers; the minimum molar% of either B, C, or A used from the polymer is 1% and the maximum molar% of either of A, B and C is 98%; and "co" is a designation for a polymer system with an unspecified arrangement of two or more monomer components. In addition, the preparation is conducted in one form, the absent crosslinked agents and by a water-in-oil emulsion process, so that the Huggxns constant (k ') determined in 0.01M NaCl is greater than 0.5 and the storage module (G ') for 1.5% by weight that activates the polymer solution at 6.3 Hz is greater than 50 Pa.

DETAILED DESCRIPTION OF THE INVENTION The present invention is provided for water-soluble cationic and amphoteric copolymers with unique physical characteristics, methods for making the copolymers, and methods for making cellulosic fiber compositions comprising adding the copolymer Cationic and amphoteric soluble in water to a slurry of cellulose pulp. The general structure of the water soluble cationic copolymer of the present invention is provided in Formula I. The general structure of the amphoteric copolymers of the invention is provided in Formula II. [-B-co-C -] - (Formula I) [-B-co-C-co-A-] - (Formula II) The segment B of non-ionic polymer in Formula I and Formula II is the unit repeated formed after the polymerization of one or more non-ionic monomers. Exemplary monomers encompassed by B include, but are not limited to, acrylamide; methacrylamide; N-alkyl acrylamides, such as N-methylacrylamide; N, N-dialkylacrylamide, such as N, N-dimethylacrylamide; methyl methacrylate; methyl acrylate; acrylonitrile; N-vinyl methylacetamide; N-vinylformamide; N-vinylmethylformamide; vinyl acetate; N-vinyl pyrrolidone, mixtures of any of the foregoing and the like. The invention contemplates that other types of nonionic monomers can be used. The segment C of cationic polymer in Formula I and Formula II is the repeat unit formed after the polymerization of one or more cationic monomers. Exemplary monomers encompassed by C include, but are not limited to, cationic ethylenically unsaturated monomers such as diallyldialkyl ammonium halides, such as diallyldimethylammonium chloride; (meth) acrylates of the dialkylaminoalkyl compounds, such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, 2-hydroxydimethylaminopropyl (meth) acrylate, aminoethyl (meth) acrylate, and the salts and quaternaries thereof; N, N-dialkylaminoalkyl (meth) acrylamides, such as?,? - dimethylaminoethylacrylamide, and the salt and quaternaries thereof and mixture of the above and the like. The segment A of the anionic polymer in Formula II is the repeated unit formed after the polymerization of one or more anionic monomers. Exemplary monomers encompassed by A include, but are not limited to, free acids and salts of acrylic acid; methacrylic acid; maleic acid; Itaconic acid; acrylamido glycolic acid; 2-acrylamido-2-methyl-l-propanesulfonic acid; 3-allyloxy-2-hydroxy-l-propanesulfonic acid; styrenesulfonic acid; vinylsulfonic acid; vinylphosphonic acid; 2-acrylamido-2-methylpropan-phosphonic acid; mixtures of any of the foregoing and the like. The molar percentage of B: C of nonionic monomer to the cationic monomer of Formula I can fall within the range of about 99: 1 to 1:99, or about 99: 1 to about 50:50 or about 95: 5 to about 50:50, or about 95: 5 to about 75:25, or 90:10 to 60:40, preferably the range is from about 95: 5 to about 60:40 and even more preferably the range is about 90:10 at approximately 70:30. In this respect, the molar percentages of B and C must result in 100%. It is understood that more than one kind of nonionic monomer may be present in Formula I. It is also understood that more than one class of cationic monomer may be present in Formula I. With respect to the molar percentages of the amphoteric polymers of the Formula II, the minimum amount of each of A, B and C is about 1% of the total amount of monomer used to form the polymer. The maximum amount of A, B or C is approximately 98% of the total amount of monomer used to form the polymer. Preferably the minimum amount of A is about 5%, more preferably the minimum amount of A is about 7% and even more preferably the minimum amount of each of A is about 10% of the total amount of monomer used to form the polymer. Preferably the minimum amount of each of B is about 5%, more preferably the minimum amount of B is about 7% and even more preferably the minimum amount of B is about 10% of the total amount of monomer used to form the polymer. Preferably the minimum amount of each of C is about 5%, more preferably the minimum amount of C is about 7% and even more preferably the minimum amount of C is about 10% of the total amount of monomer used to form the polymer. Preferably the amount of C (cationic polymer segment) in the final polymer is not more than about 50% of the total, still more preferably not more than about 40% of the total. Preferably the amount of A (anionic polymer segment) in the final polymer is not more than about 80, more preferably not more than about 70% and even more preferably not more than about 60%. In this respect, the molar percentages of A, B and C must total 100%. It is understood that more than one class of nonionic monomer may be present in Formula II, more than one class of cationic monomer may be present in Formula II, and that more than one class of anionic monomer may be present in Formula II. . In a preferred embodiment of the invention, the water-soluble cationic or amphoteric copolymer is defined wherein B, the non-ionic polymer segment, is the repeat unit formed after the polymerization of the acrylamide. In another preferred embodiment of the invention the amphoteric water soluble copolymer is defined wherein B, the nonionic polymer segment, is the repeat unit formed after the polymerization of the acrylamide and A is a salt of acrylic acid. When a salt form of an acid is used to make an amphoteric polymer it is preferred that the cation of the salt be selected from Na +, K + or NH +. It is also an aspect of this invention that cationic and amphoteric water soluble copolymers are prepared in such a way that the resulting polymers exhibit unique physical characteristics and provide unanticipated activity. The resulting water-soluble cationic and amphoteric copolymer is not considered to be a cross-linked polymer in which no cross-linking agent is used in the preparation. It is thought that small amounts of the crosslinking agent should significantly affect the properties of the polymer of the present invention. The physical characteristics of water-soluble cationic and amphoteric copolymers are unique in that their Huggins constant (k ') as determined in 0.01 M NaCl is greater than 0.5 and the storage modulus (C) for 1.5% active weight the solution of the amphoteric polymer or 3.0% by active weight for a cationic polymer solution, at 6.3 Hz is greater than 50 Pa, preferably greater than 75 and even more preferably greater than 100, or greater than 175, or greater than 200, or greater than 250. The Huggins constant is greater than 0.5, preferably greater than 0.6, or greater than 6.5, or greater than 0.75, or greater than 0.9, or greater than 1.0. The water-soluble cationic and amphoteric copolymers of the present invention are preferably prepared by a reverse emulsion (water-in-oil) polymerization technique. Such processes are known to those skilled in the art, for example, see U.S. Patent No. 3,284,393, and Reissued U.S. Patent Nos. 28,474 and 28,576, incorporated herein by reference. The preparation of an aqueous solution of the emulsion polymer can be carried out by inversion by adding the emulsion polymer to water, wherein the emulsion or water can also contain a defibrating surfactant. Shredding surfactants are additional surfactants that are added to an emulsion to promote investment. The resulting copolymers can also be further isolated by precipitating them in an organic solvent such as acetone and drying in a powder form or spray drying in a powder form. The powder can easily be dissolved in an aqueous medium for use in desired applications. In general, a reverse emulsion polymerization process is conducted by 1) preparing an aqueous solution of the monomers, 2) adding the aqueous solution to a hydrocarbon liquid containing the appropriate surfactant or surfactant mixture to form a monomer emulsion in reverse, 3) subjecting the monomer emulsion to free radical polymerization, and 4) optionally adding a dewatering surfactant to improve the inversion of the emulsion when added to water. The polymerization of the emulsion can be carried out in any manner known to those skilled in the art. The initiation can be carried out with a variety of thermal and redox free radical initiators including the azo compounds such as azobisisobutyronitrile and the like. Polymerization can also be carried out by photochemical irradiation processes, irradiation or by ionizing radiation with a 60Co source. Preferred initiators are oil-soluble thermal initiators. Typical examples include, but are not limited to, 2, 2'-azobis- (2, -dimethylpentanonitrile); 2,2'-azobisisobutyronitrile (AIBN); 2, 2'-azobis- (2, -methylbutanonitrile); 1, 1 '-azobis- (cyclohexanecarbonitrile); benzoyl peroxide, lauryl peroxide and the like. Any of the chain transfer agents known to those skilled in the art can be used to control molecular weight. These include, but are not limited to, alkyl alcohols such as isopropanol, amines, mercaptans, such as mercaptoethanol, phosphites, thioacids, allyl alcohol, and the like. The aqueous solution typically comprises an aqueous mixture of non-ionic monomer or mixtures of non-ionic monomers, and a cationic monomer or mixtures of cationic monomers. For the amphoteric copolymer, the aqueous solution typically comprises an aqueous mixture of non-ionic monomer or mixtures of non-ionic monomers, a cationic monomer or mixtures of cationic monomer and an anionic monomer or mixtures of anionic monomers. The aqueous phase can also comprise as many conventional additives as desired. For example, the mixture may contain chelating agents, pH adjusters, initiators, chain transfer agents as described above, and other conventional additives. For the preparation of the water-soluble cationic and amphoteric copolymer materials the pH of the aqueous solution is from about 2 to about 12 and is preferably equal to or greater than 2 and less than 10, more preferably the pH is greater than 2 and less that 8, and even more preferably the pH is about 3 to 7 and more preferably the pH is about 4 to about 6. The hydrocarbon liquid typically comprises straight chain hydrocarbons, branched chain hydrocarbons, saturated cyclic hydrocarbons, aromatic hydrocarbons or mixtures thereof. The surfactants or surfactant mixtures used in the invention are generally soluble in oil. One or more surfactants can be used. The surfactant or surfactant mixture selected for the invention includes at least one diblock or triblock surfactant. The choice and the amount of surfactant or surfactant mixtures are selected to produce a reverse monomer emulsion for the polymerization. The surfactants used in emulsion polymerization systems are known to those skilled in the art, for example, see "Hypermer Polymeric Surfactants: Emulsifiers for Inverse Polymerization Processes," ICI Surfactants product literature, ICI Americas Inc., 1997. Exemplary surfactants include, but are not limited to, sorbitan monooleate (eg, Atlas® G-946, Uniqema, New Castle, DE), sorbitan sequioleate, sorbitan trioleate, polyoxyethylene sorbitan monooleate, di-2-ethylhexylsulfosuccinate, oleamido-propyldimethylamine , sodium isostearyl-2-lactate of the mixtures thereof. The polymeric diblock and triblock surfactants are used in the present invention. Exemplary polymeric diblock and triblock surfactants include, but are not limited to, diblock and triblock copolymers based on the polyester derivatives of fatty acids and poly [ethylene oxide] (e.g., Hypermer® B246SF, Uniqema), diblock and poly triblock copolymers [ethylene oxide] and poly [propylene oxide], diblock and triblock copolymers based on polyisobutylene succinic anhydride and poly [ethylene oxide], mixtures of any of the foregoing and the like. Preferably, the diblock and triblock copolymers are based on the polyester derivatives of fatty acids and poly [ethylene oxide]. When a triblock surfactant is used, it is preferable that the triblock contains two hydrophobic regions and a hydrophilic region, i.e., hydrophobic hydrophilic hydrophobe. Preferably, one or more surfactants are selected to obtain an HLB (Hydrophobic-lipophilic Balance) value ranging from about 2 to 8, preferably 3 to 7 and more preferably about 4 to 6. The amount (based on percent by weight) of the diblock or triblock surfactant depends on the amount of monomer used. The ratio of the diblock or triblock surfactant in the monomer is at least about 3 to 100. The amount of diblock or triblock surfactant in the monomer can be greater than 3 to 100 and preferably is at least about 4 to 100 and more preferably at least about 5 to 100, and more preferably at least about 5.5 to 100, and more preferably at least about 6 to 100 and even more preferably at least about 7 to 100. The diblock or triblock surfactant is the primary surfactant of the emulsification system. A secondary surfactant can be added to facilitate handling and processing, improve the stability of the emulsion or alter the viscosity of the emulsion. Examples of secondary surfactants include, but are not limited to, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, polyethoxylated sorbitan fatty acid esters, ethylene oxide adducts and / or propylene oxide of alkylphenols, adducts of ethylene oxide and / or propylene oxide of long-chain alcohols or fatty acids, mixed ethylene oxide / propylene oxide block copolymers, alkanolamides, mixtures thereof and the like. The polymerization of the inverse emulsion can be carried out in any manner known to those skilled in the art, for example see Allcock and Lampe, Contemporary Polymer Chemistry, (Englewood Cliffs, New Jersey, PRENTICE-HALL, 1981), Chapters 3-5 . The present invention covers the need for a cellulosic fiber composition comprising cellulosic fiber and the copolymer of the present invention. The present invention also covers the need for a method for making the cellulosic fiber composition comprising the step of adding the copolymer of the present invention, in a cellulose slurry or cellulose pulp slurry. The copolymers of the invention can also be used in systems and processes for papermaking. The copolymers are useful as retention and drainage aids as well as contaminant control adjuvants. In the manufacture of commercial paper, a slurry of cellulose fibers or pulp is deposited on a wire or cloth for making moving paper. The slurry may contain other chemicals, such as size agents, starches, deposit control agents, mineral spreaders, pigments, fillers, organic or inorganic coagulants, conventional flocculants or other common additives in pulp. The water in the deposited slurry is removed to form a sheet. Ordinarily the sheets are then pressed and dried to form paper or cardboard. The copolymers of the invention are added to the slurry before they reach the wire to improve the drainage or drying and the retention of the fine fiber and fillers in the slurry. As a contaminant control adjuvant, the copolymers of the present invention inhibit the resin deposition and tackiness of the virgin or recycled pulp material in the papermaking equipment. The copolymers of the present invention are added to the pulp slurry where they interfere with the agglomeration of the resin and tackiness that would otherwise detrimentally affect paper, papermaking equipment or papermaking processes. The cellulose fiber pulps suitable for the method of the invention include conventional papermaking materials such as traditional chemical pulp. For example, bleached and unbleached sulfate pulp and sulfite pulp, mechanical pulp such as distillation wood, thermomechanical pulp, chemo-thermomechanical pulp, recycled pulp such as old corrugated containers, newsprint can be used. , office waste, magazine paper and other non-inked waste, de-inked waste, and mixtures thereof. The copolymer of the invention can be provided for the end-use application in a number of physical forms. In addition to the original emulsion form, the inventive copolymer can also be provided as an aqueous solution, dry solid powder, or form of dispersion. The inventive copolymer is typically diluted at the application site to produce an aqueous solution of 0.1 to 1% active polymer. This diluted solution of the inventive copolymer is then added to the paper process to affect retention and drainage. The inventive copolymer can be added to the coarse material or thin material, preferably the thin material. The copolymer can be added to a feed point, or the feed can be fractionated so that the copolymer is simultaneously fed to two or more separate feed points. Typical material addition points include the feed point or points before the feed pump, after the feed pump and before the pressure screen, or after the pressure screen. The inventive copolymer is preferably employed in a proportion from about 0.005 kg (0.01 Ib.) To about 4.53 kg (10 Ibs.) Of active polymer per ton of cellulose pulp, based on the dry weight of the pulp. The concentration of the copolymer is more preferably from about 0.23 kg (0.05 Ib.) To about 2.26 kg (5 lbs.) Of active polymer per ton of dry cellulose pulp and even more preferably 0.045 to 0.68 kg (0.1 to 1.5 lbs. ) of active polymer per ton of dry cellulose pulp. The present invention will now be further described with reference to the specific examples that are considered only as illustrative and do not restrict the scope of the present invention.

EXAMPLES Examples of Water Soluble Cationic and Amphoteric Copolymers and Comparative Copolymers Amphoteric Copolymers Example 1 In a suitable reaction flask equipped with an overhead mechanical stirrer, thermometer, nitrogen spray tube and condenser are charged to an oil phase of paraffin oil (139.72). g Exxsol® D80, Exxon, Houston, TX) and surfactants (4.66g Atlas® G-946 and 9.32g Hypermer® B246SF, Niiqema, New Castle, DE). The temperature of the oil phase was then adjusted to 37 ° C. An aqueous phase was prepared separately which comprises 53% by weight of acrylamide solution in water (115.76 g), acrylic acid (56.54 g), chloride [2 (acryloyloxy) ethyl] trimethyl ammonium (AETAC) (25.89g) (80% by weight of the solution), deionized water (88.69g), and Versenex® 80 (Dow Chemical, Midland, MI) chelating solution (0.6 g). The aqueous phase was then adjusted to pH 5.4 with the addition of sodium hydroxide solution in water (31.07 g, 50% by weight). The temperature of the aqueous phase after neutralization was 3 ° C. . The aqueous phase was then charged to the oil phase while mixing simultaneously with a homogenizer to obtain a stable water-in-oil emulsion. This emulsion was then mixed with a 4-blade glass stirrer while being sprayed with nitrogen for 60 minutes. During the nitrogen sparge the temperature of the emulsion was adjusted to 50 ± 1 ° C. Subsequently, the roclo was discontinued and a blanket of nitrogen was applied. Polymerization was initiated by feeding 3% by weight of AIBN (0.12g) of the toluene solution (3.75g) over a period of 2 hours. This corresponds to an initial AIBN load such as AIBN of 250 ppm on a total monomer base. During the feeding course, the batch temperature was left exotherm at 62 ° C (~ 50 minutes) after which the batch was maintained at 62 ± 1 ° C for 1 hour. Subsequently 3% by weight of AIBN (0.05g) of the solution in toluene (1.50g) was then loaded in a charge. This corresponds to a secondary AIBN load such as 100 ppm AIBN on a total monomer base. Then the batch was maintained at 62 + 1 ° C for 2 hours. Then the batch was cooled to room temperature and the product was collected.

Examples 2-5 Examples 2-5 are prepared as Example 1 above with the following modifications: The amount of AETAC is increased from 5% (moles of monomer) to 10, 15, 20 and 25% respectively, and the amount of Acrylic acid is reduced from 45% (moles of monomer) to 40, 35, 30 and 25% respectively). The amount of acrylamide remains constant at 50 mole percent. The water was adjusted to account for the dilution in AETAC and acrylamide monomers.

Examples 6-10 Examples 6-10 are prepared as example 1 with the following exceptions: The cationic monomer used was acryloyloxyethyldimethylbenzylammonium chloride (AEDBAC) (ADAMQUAT® BZ 80, Elf Atochem, Philadelphia, PA) (80% by weight of solution) instead of AETAC. The cationic monomer level was 5, 10, 15, 20 and 25% on a molar basis for examples 6, 7, 8, 9 and 10 respectively and the amount of acrylic acid was decreased from 45% (moles of monomer) to 40, 35, 30 and 25% respectively). The amount of acrylamide remained constant at 50 mole percent. The water was adjusted to account for the dilution in AEDBAC and acrylamide monomers.

Cationic Copolymers Example 11 In a suitable reaction flask equipped with an overhead mechanical stirrer, thermometer, nitrogen spray tube and condenser were loaded into an oil phase of paraffin oil (139.7g, Escaid® 110 oil, Exxon, Houston, Tx) and surfactants (4.66g Atlas® G-946 and 9.32g Hypermer® B246SF). The temperature of the oil phase was then adjusted to 45 ° C. An aqueous phase was prepared separately which comprises 53% by weight of the solution of acrylamide in water (252.3g), acryloyloxyethyltrimethylammonium chloride (AETAC) (80% by weight of solution) (23.52g), deionized water (56. Ig ), and Versenex® 80 (Dow Chemical) chelating solution (1.39g). The solution was mixed and heated to about 30 ° C.

The aqueous phase was then charged to the oil phase while mixing simultaneously with a homogenizer to obtain a stable water-in-oil emulsion. This emulsion was then mixed with a 4 paddle glass agitator with nitrogen for 60 minutes. During the nitrogen spray, the temperature of the emulsion was adjusted to approximately 63 ° C. Subsequently, the spray was discontinued and a blanket of nitrogen was applied. Polymerization was started by adding 50 ppm (based on moles of total monomer) as a dispersion of 3% by weight of AIBN in Escaid 110 oil (0.016 g of AIBN). During the course of the polymerization, the batch temperature was maintained at approximately 63 ° C. After the exotherm began to decrease, a second load of 50 ppm of AIBN was added. When the exotherm decreased again, the reactor and contents were heated to 65 ° C and 200 ppm of AIBN were added. The reaction was maintained at 65 ° C until it reached the desired residual monomer levels. The batch was then cooled and the additional inverting surfactant was added. The product was also cooled to room temperature and collected.

Examples 12-14 Examples 12-14 were prepared as example 11 above with the following modifications: The amount of AETAC was increased from 5% (moles of monomer) to 10, 15 and 25% respectively. The amount of acrylamide was decreased correspondingly to the percent of AETAC in each example. The water was adjusted to account for the dissolution in AETAC and the acrylamide monomers.

Examples 15-17 Examples 15-17 were prepared as Example 11 with the following exceptions: The cationic monomer used was acryloxyethyldimethylbenzylammonium chloride (ADAMQÜAT® BZ 80, Elf Atochem, Philadelphia, PA) (80% by weight of solution) in place of AETAC. The level of cationic monomer was 5, 10 and 15% on a molar basis for examples 15, 16 and 17 respectively. The water acrylamide levels were adjusted accordingly for each example.

Retention Data of Water Soluble Cationic and Amphoteric Copolymers and Comparative Copolymers The retention data were provided in Tables 1 to 10. Tables 1 to 8 provide the retention data for the amphoteric samples. Tables 9 and 10 provide the retention data for the cationic samples. These evaluations were carried out in an alkaline supply or supply of defibrated wood by distillation generated by the laboratory.

Alkaline raw materials are prepared from dried market length pulps of hardwood and softwood, water and additional materials. First the dry market length pulp of hardwood and softwood is separately refined in a Valley Beater laboratory (Voith, Appleton, WI). These pulps are then added to an aqueous medium comprising a mixture of local hard water and deionized water in a representative hardness. The inorganic salts are added in amounts so that they provide this medium with a representative alkalinity and a total solution conductivity. Hardwood and soft wood are dispersed in the aqueous medium at typical weight ratios. Precipitated calcium carbonate (PCC) is introduced into the raw materials at 25% by weight, based on the combined dry weight of the pulps so as to provide final raw materials comprising 80% fiber and 20% PCC filler . The distillation wood raw materials are prepared from dry market length pulps of softwood, thermomechanical pulp (TMP), water and additional materials. First the dry market length pulp of softwood and TMP are separately refined in a Valley Beater laboratory (Voith, Appleton, WI). These pulps are then added to an aqueous medium comprising a mixture of local hard water and deionized water in a representative hardness. The inorganic salts are added in amounts so that they provide this medium with a representative alkalinity and a total solution conductivity. Pectin gum is a water soluble polygalacturonase added in a representative amount to provide an organic material soluble in raw materials. The soft wood and TMP are dispersed in the aqueous medium at typical weight ratios. The calcined clay is introduced into the raw materials at 30 percent by weight, based on the combined dry weight of the pulps, so that it provides final raw materials comprising 77% fiber and 23% clay filler. The pH of the distillation wood raw material material was adjusted to about 4.5 to about 4.8 prior to the test. The emulsions must be inverted to form an aqueous solution prior to the test. Prior to inverting the water-soluble cationic and amphoteric copolymer emulsions for analysis, about 2% by weight of a defibrating surfactant, eg, 80:20 per weight mixture of Tergitol® 15-S-9 (Dow Chemical. , MI) and Aerosols OT-S (Cytec Industries, West Patterson, NJ), were added. The pH of inverted water soluble cationic and amphoteric copolymers was then adjusted to a minimum of 6.0 with aqueous sodium hydroxide or ammonium hydroxide, as required. To evaluate the performance of the water-soluble cationic and amphoteric copolymers of the present invention, a series of Britt jar retention tests were conducted compared to Polyflex GP.3 (Ciba Specialty Chemicals, Tarrytown, NY), an organic drainage adjuvant. commonly referred to within the industry as a "micropolymer"; EM 635 (Chemtall, Riceboro, GA) is a linear flocculating emulsion of sodium acrylate / acrylamide 50/50 mol%; BMA 780 is silica solution (Eke Chemicals, arietta, GA); SP 9232 is Performs SP9232 (Hercules Incorporated, Wilmington, DE), a structured organic particle. The cationic flocculants used in the performance test cationic polyacrylamide treatment program (referred to as CPAM) were 90/10 mole% acrylamide / AETAC copolymers (Performs® PC 8138 and Performs® PC 8715, Hercules Incorporated, Wilmington DE ). PC 8138 (Performs® PC 8138) was provided as an emulsion. PC 8715 (Performs® PC 8715) was provided as a powder. Cal Corporation, Baltimore, MD). Unless stated otherwise, all percentages, parts, Ib. / ton, etc., are per asset. The data set forth in Tables 1 to 10 illustrate the retention activity of the water-soluble cationic and amphoteric copolymers of the invention compared to the materials listed in the foregoing. The Britt Fines retention test (FPFR) was carried out according to TAPPI Method T261 with the following modifications and specifications: 125P. A sieving Britt jar was used for the entire test. The mixing speed was 1600 rpm for wood raw materials defibrated by distillation and was 1200 rpm for alkaline raw materials. The sequence of addition is observed in the tables.

TABLE 1: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Additive Distilled Distressed Woods # 1 10 # / T Stalok Additive # 2 5 # Additive TAIum # 3 IT (active) Mixing time Additive # 4 # / T (active) Retention seconds Britt Ends Average none 10 19.3 PC 8138 0.5 10 36.1 PC 8715 0.5 10 38.3 SP9232 0.5 10 25.8 EM 635 0.5 10 24.8 Example 6 0.5 10 20.2 Example 7 0.5 10 19.7 Example 8 0.5 10 18.1 Example 9 0.5 10 19.2 Example 10 0.5 10 21.1 TABLE 2: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Additive Distilled Distressed Woods # 1 10 # / T Stalok Additive # 2 5 # / T Additive AI # 3 (active) Mixing time Additive # 4 # / T (active) Retention seconds Britt Average Ends PC 8715 0.5 10 none 38.3 PC 8715 0.5 10 BMA 80 2 40.9 PC 8715 0.5 10 SP9232 0.5 40.6 PC 8715 0.5 10 EM 635 0.5 39.9 PC 8715 0.5 10 Example 6 0.5 30.6 PC 8715 0.5 10 Example 7 0.5 29.0 PC 8715 0.5 10 Example 8 0.5 27.7 PC 8715 0.5 10 Example 9 0.5 28.3 PC 8715 0.5 10 Example 10 0.5 28.3 TABLE 3 > : Sample Evaluation of! Copcopimero Anfoterico RAW MATERIALS: Additive Distilled Distressed Woods # 1 10 # / T Stalok Additive # 2 1 # / T PC 1279 CORRIDA # Additive # 3 fflT (active) Mixing time Additive # 4 #G? (active) Retention seconds Britt Averages Average none 10 19.3 1 PC 8715 0.5 10 38.5 8 EM 635 0.5 10 25.4 9 Example 3 0.5 10 25.1 Example 4 0.5 10 24.6 11 Example 5 0.5 10 24.8 12 Example 2 0.5 10 25.4 13 Example 1 0.5 10 25.5 TABLE: Evaluation of Anfoteric Copolymer Samples RAW MATERIALS: Additive Distilled Distressed Woods # 1 1Q # T Stalok Additive # 2 1 # T PC 1279 Additive # 3 # / T (active) Mixing time Additive # 4 # / T (active) Retention seconds Britt Averages PC 8715 0.5 10 none - 38.5 PC 8715 0.5 10 EM 635 0.5 40.8 PC 87 5 0.5 10 Example 3 0.5 30.3 PC 8715 0.5 10 Example 4 0.5 30.6 PC 8715 0.5 10 Example 5 0.5 30.2 PC 8715 0.5 10 Example 2 0.5 30.7 PC 8715 0.5 10 Example 1 0.5 31.4 TABLE 5: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Additive Distilled Distressed Woods # 10 # / T Stalok Additive # 2 5 # T Additive AI # 3 # / T (active) Mixing time Additive # 4 # / T (active) Retention seconds Britt Ends Average none 35.0 PC 8138 0.4 10 57.3 Polyflex CP.3 0.4 10 68.3 SP9232 0.4 10 72.1 EM 635 0.4 10 65.5 Example 6 0.4 10 52.7 Example 7 0.4 10 46.3 Example 8 0.4 10 42.0 Example 9 0.4 10 40.7 Example 10 0.4 10 32.6 TABLE 6: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Alkaline Additive # 1 io Stalok Additive # 25 # / T alum Additive # 3 # / T Additive Time # 4 # / T (active) (active) mix Retention seconds Britt Average Ends PC 8138 0.4 10 none 57.3 PC 8138 0.4 60 Polyflex CP .2 0.4 77.8 PC 8138 0.4 60 SP 9232 0.4 77.1 PC 8138 0.4 60 EM 635 0.4 69.0 PC 8138 0.4 60 Example 6 0.4 59.8 PC 8 38 0.4 60 Example 7 0.4 53.5 PC 8138 0.4 60 Example 8 0.4 48.2 PC 8138 0.4 60 Example 9 0.4 45.2 PC 8138 '0.4 60 Example 10 0.4 34.9 TABLE 7: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Alkaline Additive # 1 10 # / T Stalok Additive # 2 5 # / T alum Additive # 3 Additive Time # 4 # / T (active) "(active) Mix Retention seconds Britt Averages Average none 35.0 PC 8138 0.4 10 54.7 EM 635 0.4 10 65.0 Example 3 0.4 10 41.4 Example 4 0.4 10 37.9 Example 5 0.4 10 38.9 Example 2 0.4 10 44.7 Example 1 0.4 10 55.7 TABLE 8: Evaluation of Amphoteric Copolymer Samples RAW MATERIALS: Alkaline Additive # 1 10 # / T Stalok Additive # 2 5 # / T alum Additive # 3 # / T Additive Time # 4 # / T (active) (active) mixture Retention seconds Britt Average Ends PC 8138 0.4 10 none 54.7 PC 8138 0.4 60 EM 635 0.4 67.3 PC 8138 0.4 60 Example 3 0.4 45.2 PC 8138 0.4 60 Example 4 0.4 39.8 PC 8138 0.4 60 Example 5 0.4 40.3 PC 8138 0.4 60 Example 2 0.4 48.5 PC 6138 0.4 60 Example 1 0.4 59.5 TABLE 9: Anfoteric Copolymer Samples Evaluation RAW MATERIALS: Alkaline Additive # 1; 10 # / T Stalok Additive # 2: 5 m Alum Additive # 3 m Time (active) of mixing Retention seconds Britt Ends Average none 35.2 PC 8138 0.4 10 57.3 Example 11 • 0.4 10 36.9 Example 2 0.4 10 44.0 Example 13 0.4 10 45.9 Example 14 0.4 10 55.0 Example -j 5 0.4 10 36.6 Example - Q 0.4 10 44.1 Example 17 0.4 10 47.1 TABLE 10: Evaluation of Cationic Copolymer Samples RAW MATERIALS: Distilled Distillation Timings Additive # 1: 10 # / T Stalok Additive # 2: 5 # / T A1um Additive # 3 m Time Retention (active) of Britt mixture Fines seconds Average none 19.3 PC 8138 0.5 10 36.1 PC 8715 0.5 10 38.3 Example 11 0.5 10 23.2 Example 12 0.5 10 26.6 Example 13 0.5 10 23.5 Example 14 0.5 10 21.6 Example 15 0.5 10 25.2 Example 16 0.5 10 29.6 Example 17 0.5 10 31.5 Alum is aluminum sulphate-octadecahydrate available as an aqueous solution. 50% (Delta Chemical Corporation, Baltimore, MD). PC 1279 is Performs® PC 1279 (Hercules Incorporated), a cationic polyamide coagulant. Stalok is Stalok® 400 (A.E. Staley, Cedar Rapids, Iowa), a modified potato starch. Rheological Properties of Water-soluble Cationic and Amphoteric Copolymers and Comparative Copolymers Emulsions must be inverted to form an aqueous solution prior to testing. The test for reversing the water-soluble cationic and amphoteric copolymer emulsions for analysis, about 2% by weight of a defibrating surfactant, eg, 80:20 by weight mixture of Tergitol® 15-S-9 (Dow Chemical .

Midland, MI) and Aerosols® OT-S (Cytec Industries, West Patterson, NJ), were added. The pH of the inverted water soluble cationic and amphoteric copolymers was then adjusted to a minimum of 6.0 with aqueous sodium hydroxide or ammonium hydroxide, as required. A discussion of these rheological techniques is provided by Macosko, Rheology: Principies, Measurements, and Applications (New York, Wiley, 1994); L.H. Sperling, Introduction to Polymer Science (New York, Wiley-Interscience, 1992); and J. Ferry, Viscoelastic Pxperties of Polymers, 3rd edition, (New York, J. Wiley &Sons, 1980). The viscoelastic behavior as discussed herein is a time dependent on response to an applied force where the short time or the high frequency of the material showed hardness or vitreous properties, and a long or infrequent time a material can flow and show properties of viscosity. The viscoelastic properties were determined with the polymer solutions at 1.5% (w / w) in deionized water, using a Haake RS-75 controller voltage rheometer. A frequency sweep was conducted with the rheometer in the dynamic oscillation mode, at a constant voltage determined to be within the linear viscoelastic region, and a frequency range from 0.01 Hz to 10 Hz. The production of this test was defined both in an elastic component of the material, as in the energy stored by the oscillatory cycle, - and a viscous component, or the energy lost per cycle. The storage module (G ') was defined as: G' (Pa) = (x0 / Yo) eos d and the loss modulus (G ") was defined as: G" (Pa) = (T0 / y0) sin d where t0 is the voltage amplitude,? 0 is the stress amplitude, and d is the change in phase angle between the stress and the resultant stress. In the terminal regime (low frequency), the loss modulus is greater than the storage module for the linear polymers, as time goes by it allows the polymer chains to release and show predominantly viscosity behavior. When the frequency increases, an elastic level regime occurs where the time required for the polymer chains to release is greater than the time of the test. In this region, the storage module is larger than the loss module, and the material will appear to be a network comprised of permanent wire fences. The storage module is independent of the test frequency in this regime. The module is a function of network junction concentration as defined by rubber elasticity theory: GN = nRT where GN is the level module, n is the concentration of the network junctions, R is the gas constant, and T is the temperature. The level GN module can be considered to be similar in magnitude to the storage module G 'in the level regime. When the concentration of network junctions increases, the module will increase. These network junctions can be affected by either chemical or physical cross-links. The properties of the diluted solution provide a relative indication of polymer hydrodynamic volume (HDV) and molecular weight. In this experiment, the viscosity of the solvent (? 0) is compared to the viscosity of the polymer solution (?). The specific viscosity (nsp) is the unitless relation as described by the following equation: T? = (? / ??) - i The reduced specific viscosity (RSV) is the specific viscosity divided by the concentration. The intrinsic viscosity [?], Or IV, is the specific viscosity divided by the concentration (c) of the polymer when the concentration is extrapolated to the zero concentration. [?] = [? 3? / C] c? 0 Units for IV are deciliter per gram (dL / g) and describe the hydrodynamic volume of a polymer in the solution. Thus, a high IV indicates an extensive hydrodynamic volume in the solution, and a high MW when compared to conventional polymers of the similar composition in a similar solvent. The specific viscosities were determined in 0 01 M NaCl with dilution concentrations from 0.0025% to 0.025% using a Ubbelohde "OC" viscometer at 30 ° C. The constant (k ') of Huggins without unit is determined from the slope of the specific viscosity data according to:? 5? / C = [?] + K' [?] 2s where the value of c is between 0.0025% in weight and 0.025% in weight. As reviewed by Mark et al., Editors, Encyclopedia of Polymer Science and Engineering (New York, J. Wiley & amp;; Sons, 1988), Vol. 1, pp. 26-27, typical k 'values for linear polymers are in the order of about 0.25-0.50. An increase in the value of k 'is indicative of an increase in the "structure" of the polymer, and can be attributed to several factors including molecular association. The values of k 'in Tables 11 and 12 for the ???? linear are all 0.3 to 0.4, while values greater than 0.0.5 are obtained for the preferred water-soluble copolymers of the present invention, further supporting the presence of a non-linear species.

TABLE 11: Evaluation of Amphoteric Copolymers Dynamic Mechanical Studies 1. 5% Active Polymer k ' Polymer G ', Pa, 6.3 Hz EM 635 130 0.30 Example 1 462 1.49 Example 2 289 3.10 Example 3 138 4.01 Example 4 6.46 Example 5 1.72 Example 6 384 9.7 Example 7 305 9.7 Example 8 143 - Example 9 19 - TABLE 12: Evaluation of Cationic Copolymers Dynamic Mechanical Studies 3. 0% Polymer Active Polymer G ', Pa, 6.3 Hz k' PC 8138 104 PC 8715 108 0.24 Example 11 356 Example 12 336 1.10 Example 13 268 Example 14 178 1.03 Example 15 268 Example 16 162 0.58 Use 17 133 0.69 notes that the above examples have been provided simply for the purpose of explanation and will not in any way be construed as limiting the present invention. Although the present invention has been described with reference to an exemplary embodiment, it is understood that the words that have been used herein are description and illustration words, rather than words of limitation. Although the present invention has been described herein with reference to particular media, materials and embodiments, it is not intended that the present invention be limited to the details described herein. The water-soluble cationic and amphoteric copolymers of the present invention may also show unique activity in other applications such as coagulants and / or flocculants in wastewater treatment applications, or as rheology modifiers in drilling and / or cement processing applications. .

Claims (18)

1. CLAIMS 1. A water soluble copolymer composition comprising the formula I: [-B-co-C -] - wherein B is a nonionic polymer segment formed from the polymerization of one or more nonionic ethylenically unsaturated monomers; C is a segment of cationic polymer formed from the polymerization of one or more cationic ethylenically unsaturated monomers; the molar ratio B: C is from 99: 1 to 1:99 and the water-soluble cationic copolymer is prepared by a water-in-oil emulsion polymerization technique employing at least one emulsifying surfactant consisting of minus a polymeric diblock or triblock surfactant wherein the amount of at least one diblock or triblock surfactant in the monomer is about 3: 100 and wherein; the water-in-oil polymerization technique comprises the steps of: preparing an aqueous solution of monomers; adding the aqueous solution to a hydrocarbon liquid containing the surfactant or surfactant mixture to form a reverse emulsion; causing the monomer in the emulsion to polymerize by free radical polymerization in a pH range of from about 2 to less than 7; and wherein the copolymer has a constant (k ') of Huggins that is greater than 0.5; and the copolymer has a storage modulus (G ') greater than 50 Pa.
2. 2. The water-soluble copolymer composition according to claim 1, characterized in that the copolymer further comprises an anionic polymer segment, "A", in where A is an anionic polymer segment formed by the polymerization of one or more ethylenically unsaturated anionic monomers; and the minimum amount of A is 1% of the total amount of the monomer used to form the polymer.
3. 3. The composition of claim 1, wherein the B: C ratio is from about 99: 1 to about 50:50.
4. 4. The composition of claim 3, wherein the B: C ratio is from about 95: 5 to about 50:50.
5. The composition of claim 2, wherein the minimum amount of each of A, B and C is 5%.
6. The composition of claim 5, wherein the minimum amount of each of A, B and C is 7%.
7. 7. The composition of any of claims 2, 5 or 6, wherein A is selected from the group consisting of the free acids and salts of acrylic acid; methacrylic acid; maleic acid; Itaconic acid; acrylamido glycolic acid; 2-acrylamido-2-methyl-1-propanesulfonic acid; 3-allyloxy-2-hydroxy-l-propanesulfonic acid; styrenesulfonic acid; vinylsulfonic acid; vinylphosphonic acid; 2-acrylamido-2-methylpropan phosphonic acid; mixtures of any of the above.
8. The composition of any of the preceding claims 1 to 6, wherein B is selected from the group consisting of acrylamide, methacrylamide; N-alkyl acrylamides, N-N-dialkyl acrylamide; methyl methylacrylate, methyl acrylate; acrylonitrile; jV-vinyl methylacetamide JV-vinylformamide; N-vinylmethyl formamide; vinyl acetate; JW-vinyl pyrrolidone; and mixtures of any of the foregoing.
9. The composition of any one of claims 1 to 6 above, wherein C is selected from the group consisting of diallyldialkyl ammonium halides, (meth) acrylates of dialkylaminoalkyl compounds, such as dimethylaminoethyl (meth) acrylate, (meth) acrylate of diethylaminoethyl, dimethylaminopropyl (meth) acrylate, 2-hydroxydimethylaminopropyl (meth) acrylate, aminoethyl (meth) acrylate, and the salts and quaternaries thereof; N, N-dialkylaminoalkyl (meth) acrylamides, such as?,? - dimethylaminoethylacrylamide, and the salt and quaternaries thereof and mixtures of any of the foregoing.
10. The composition of any one of claims 1 to 9 above, wherein the diblock or triblock surfactant is a copolymer based on polyester derivatives of fatty acids and poly [ethylene oxide].
11. 11. The composition of any of preceding claims 1 to 10, wherein the diblock or triblock surfactant in relation to the monomer is at least about 4: 100.
12. The composition of any of the preceding claims 1 to 11, wherein the emulsifying surfactant consists of a mixture of a polymeric surfactant comprising one or two polymeric components derived from the oil-soluble complex monocarboxylic acid and a water-soluble component derived of polyalkylene glycol and sorbitan monooleate; and 2,2'-azobisisobutyronitrile are employed as the free radical initiator.
13. The composition of any one of claims 1 to 12 above, wherein the surfactant system has a combined hydrophilic-lipophilic balance of less than 8.
14. The composition of any of the preceding claims 1 to 13, wherein the surfactant diblock or triblock is a copolymer based on polyester derivatives of fatty acids and poly [ethylene oxide].
15. 15. The composition of any of preceding claims 1 to 14, wherein k 'is greater than 0.6.
16. 16. The composition of any one of preceding claims 1 to 15, wherein G 'is greater than 75.
17. 17. The composition of any of the preceding claims 1 to 16, which further comprises cellulosic fiber.
18. 18. A method for making a cellulosic fiber composition comprising adding to a cellulose pulp slurry the water-soluble cationic copolymer of any of the preceding claims 1 to 17.