MXPA97003180A - Process for pa manufacturing - Google Patents

Abstract

The present invention relates to an improvement in a process for the manufacture of paper, consisting essentially of: the formation of a slurry for the manufacture of paper, cellulosic, aqueous, the addition of certain additives to the suspension; the shear suspension, the draining of the suspension to form an eye, and the drying of the sheet to form a sheet of paper, the improvement being character in that it comprises addition to the suspension, before it is subjected to shear stress; from about 0.5 ppm to about 1,000 ppm of a cationic dispersion polymer whose cationic dispersion polymer is selected from a group of copolymers consisting of: i) a copolymer of about 10 mol% DMAEA.BCQ and about 90 mol% AcAm; ii) a copolymer of approximately 10 mol% of DMAEA.MCQ and approximately 90 mol% of AcAm, and iii) a copolymer of approximately 20 mol% of DMAEA.MCQ already about 80 mol% of AcAm, and the addition to the suspension, after the cationic polymer is added in dispersion and the suspension is subjected to shear, a microparticle selected from the group consisting of 0.11 kg / ton to 3.63 kg / ton (0.25 pounds / ton to 8 pounds / ton), a) copolymers of acrylic acid and acrylamide, b) bentonite, and c) silica disper

Description

PROCESS FOR THE MANUFACTURE OF PAPER FIELD OF THE INVENTION The present invention is in the technical field of papermaking and more particularly in the technical field of wet-part additives for the supply of papermaking.

BACKGROUND OF THE INVENTION In papermaking a slurry or slurry cellulose, aqueous suspension is formed on a sheet of paper. The cellulosic slurry generally dilutes to a consistency (percent dry weight of solids in the slurry) of less than 1 percent and frequently down 0.5 percent before the paper machine, while the supplied sheet must have less than 6 percent water Therefore, the dehydration aspects of papermaking are extremely important for the efficiency and cost of manufacturing. The method of dehydration of the minimum cost in the process is drainage or drainage, and then more expensive methods are used, for example, REF: 24673 vacuum, pressure, evaporation and the like, and in practice a combination of such methods to dehydrate, or dry the sheet to the desired water content. Since drainage or drainage is both the first method of dehydration employed and the least expensive, the improvement in drainage efficiency will decrease the amount of water required to be eliminated by other methods and therefore will improve the overall efficiency of dehydration and reduce the cost of it. Another aspect of papermaking that is extremely important for the efficiency and cost of manufacturing is the retention of supply components and within the matte fiber that is formed during papermaking. A papermaking furnish generally contains particles ranging in size from about the size of 2 to 3 milliliters of cellulose fibers, for fillers to a few microns, and for colloids. Within this range are the finely ground materials, fillers of material (used to increase the opacity, brightness and other characteristics of the paper) and other small particles that in general, without the inclusion of one or more retention aids, would pass in a portion significant, through the spaces (pores) between the cellulose fibers in the fiber matte that is formed during papermaking. A method for improving the retention of finely ground cellulose materials, mineral fillers and other furnish components on the matte of fibers is the use of a coagulant / flocculant system, added before the paper machine. In such a system, a coagulant is first added, for example a cationic synthetic polymer, of low molecular weight or a cationic starch for the supply, coagulant which in general reduces the negative surface changes present on the particles in the supply, particularly materials finely ground cellulosics and mineral fillers, and with which performs a degree of agglomeration of such particles, followed by the addition of a flocculant. Such a flocculant in general is an anionic, high molecular weight synthetic polymer that binds the particles and / or agglomerates, from one surface to another, which binds the particles in large agglomerates. The presence of such large agglomerates in the supply as the fiber mat of the paper sheet is being formed, increases the retention. The agglomerates are filtered out of the water in the fiber cloth, where the agglomerated particles would pass to a greater degree through such a paper web. While a flocculated agglomerate generally does not interfere with the drainage or drainage of fiber matte to the degree that it would occur if the supply were to gel to or contain a quantity of gelatinous material, when such flocs or lumps seep through the fiber cloth, the pores of it are to a reduced degree, which reduces the drainage efficiency thereof. So I sing, the retention must be increased with some degree of deleterious effect in the drainage. Another system employed to provide an improved combination of retention and dehydration is described in U.S. Patent No. 4,753,710 and U.S. Patent No. 4,913,775, inventors Langley et al., Issued respectively June 28, 1988 and April 3, 1990, incorporated in the present by reference. In summary, such a method adds to the aqueous, cellulosic papermaking suspension, first a linear, high molecular weight cationic polymer before the suspension is subjected to shear stress, followed by the addition of bentonite after shear stress. Shear stress is generally provided by one or more of the cleaning, mixing and pumping stages of the papermaking process, and the shear stress breaks up the large flocs or lumps formed by the high molecular weight polymer, and the additional agglomeration then it results with the addition of the bentonite clay particles. Another system uses the combination of cationic starch followed by colloidal silica to increase the amount of material retained on the fabric by the method of charge neutralization and adsorption of smaller agglomerates. This system is described in the North American patent No. 4,388,150, inventors Sunden et al., Issued June 14, 1983. In general, dehydration, and particularly dewatering by drainage or drainage, is believed to improve when the pores of the web or paper are less clogged, and that retention by adsorption compared to retention by filtration reduces such plugging of pores.

The greater retention of finely ground and filler materials allows, for a given grade of paper, a reduction in the cellulose fiber content of such paper. As lower grade pulps are used to reduce the costs of papermaking, the retention aspect of papermaking becomes even more important because the content of finely ground materials of such pulps of lower quality is in general greater than those of the highest quality pulps. The greater retention of finely ground materials, fillers and other components of the slurry reduces the amount of such waste for white water and therefore reduces the amount of material waste washes, the cost of waste disposal and the environmentally adverse effects of the same. Another important characteristic of a given papermaking process is the formation of the sheet of paper produced. The formation is determined by the variation in the transmission of light within a sheet of paper, and a high variation is indicative of the poor formation. As the retention increases to a high level, for example a retention level of 80 to 90 percent, the training parameter in general decreases sharply from good training to poor training. It is believed at least theoretically that as the retention mechanisms of a papermaking process change from filtration to adsorption, the deleterious effect on the formation, how high retention levels are achieved, will diminish, and a good combination of high retention with good formation is attributed to the use of bentonite in U.S. Patent No. 4,913,775. In general, it is desirable to reduce the amount of material used in a papermaking process for a given purpose, without diminishing the desired result. Such additive type reductions can realize both cost savings of material and benefits of handling and processing. It is also desirable to use additives that can be supplied to the paper machine without undue problems. An additive that is difficult to dissolve, mix or otherwise disperse in the aqueous medium may require expensive equipment to feed it to the paper machine. When difficulties are encountered in the supply to the paper machine, the additive is often kept in the form of an aqueous slurry by virtue of the high energy input equipment. In contrast, additives that are easily dissolved or dispersed in water require less energy and cost and their uniformity of feeding is more reliable.

BRIEF SUMMARY OF THE INVENTION The claimed invention provides a process for the manufacture of paper comprising forming a slurry for the manufacture of paper, cellulosic, aqueous, holding the slurry to one or more stages of shear, adding a mineral filler to the slurry before at least one of the shear stages, adding to the slurry after the addition of the mineral filler and before at least one of the shear stages, an effective amount of cationic dispersion polymer selected from the group consisting of copolymers of acrylamide and quaternary salt of methyl chloride of dimethylaminoethyl acrylate, methyl quaternary salt of dimethylaminoethyl acrylate, quaternary salt of dimethylaminoethyl acrylate benzyl chloride, quaternary salt of benzyl chloride of dimethylaminoethyl methacrylate and diallyldimethylammonium chloride; to subject the thick suspension to shear stress; adding a microparticle selected from the group consisting of copolymer of acrylic acid, bentonite and silica sol; drain the slurry to form a sheet; and dry the sheet to form a sheet of paper.

DESCRIPTION OF THE PREFERRED MODALITIES According to the invention, a water-soluble polymer is added to a cellulosic slurry before the formation of a paper product. The water-soluble polymer must become substantially dispersed within the slurry before the formation of the paper product in any case. The microparticle of the invention is added after the shear stress of the slurry. The addition of the polymer in an aqueous medium, for example as a water or dispersion solution, facilitates dispersion of the polymer from the slurry. In a preferred embodiment, the polymer is added to the cellulosic slurry before the draining and sheeting steps. The present process is believed to apply to all grades and types of paper products, and in addition applicable for use in all types of pulps including, without limitation, chemical pulps, which include sulfate and sulfite pulps. both hard and soft woods and acid paper pulps, thermomechanical pulps, mechanical pulps, recycled pulps, and pulped wood pulps, although it is believed that the advantages of the process of the present invention are best achieved when the pulp used It is of the chemical pulp type, chemical pulp partirly alkaline. In a preferred embodiment, the filler used in the cellulosic slurry is anionic or at least partially anionic. However, other mineral or inorganic fillers, such as calcium carbonate, clay, titanium dioxide or talc may be used or a combination may be present.

The amount of alkaline inorganic filler, such as one of the alkali carbonates, generally used in a papermaking pulp is from about 10 to about 30 parts by weight of the filler, such as CaCO3, per one hundred parts by weight of pulp. dry bin in the slurry, but the amount of such filler can sometimes be as low as about 5, or even about 2, parts by weight, and as high as about 40 or even 50 parts by weight, same base. The specific reduced viscosities of the polymers and copolymers as reported herein were determined in 0.125M sodium nitrate solution from the published data. Similarly, all molecular weights of the polymers, as reported herein, are the approximate weight average molecular weights of the polymers. The dispersion polymerization process used for the manufacture of the polymers of the invention offers numerous advantages that have previously been unusable. Since the polymers of the invention are completely synthesized in water, no oily solvent is required. This is significant since: 1) the polymers of the invention do not present a fire risk; 2) the oil is not added to the water which must be treated (more favorable to the environment); 3) the dissolution of the polymers of the invention requires only the addition of water, no special activators are necessary; 4) the ability of the polymers of the invention to dissolve / invert is superior to that of the oil dispersion latex; and 5) the polymers of the invention can be diluted to virtually any concentration by using appropriately concentrated salt water. Another main advantage is that the volume viscosity of the polymer is low, not similar to any of the oily dispersion latex polymers.

This physical property allows any normal chemical pump to supply the material to the judicial request site.

A new class of water-soluble dispersion polymers have been found to be more effective in increasing drainage and retention than currently available chemical treatments, as will be discussed in more detail below, the polymer dispersion of the invention is prepared in an aqueous solution of a polyvalent anionic salt The polymer dispersion of the invention achieves fine particle sizes and aqueous solubilities not available with other polymers used for this application Furthermore, there does not appear to be a problem with overfeeding the polymer dispersion which is a disadvantage with the latex polymers According to the method, the dispersion polymer of the invention is added to a slurry for cellulosic papermaking.The polymer is added in an effective amount from 0.5 to about 100. ppm, more preferably, the amount of the polymer added and s from 2 to about 40 ppm, and more preferably from about 4 to about 25 ppm. It is believed that there does not seem to be a maximum dosage at which polymers adversely affect the system. In some higher doses, the beneficial effect can be stabilized, and on a cost basis such higher doses, probably above about 100 ppm, are not cost effective. The polymers of the invention are preferably added to the system in a pure form. However, in some applications, the polymers can be added as an aqueous solution. Preferred polymers of the invention are manufactured by Hymo Corporation, Japan. The methods for the manufacture of the polymer dispersion used in the invention are described in detail in U.S. Patent No. 5,006,590 and U.S. Patent No. 4,929,655, assigned to Kyoritsu Yuki Co. , Ltd, Tokyo, Japan. The descriptions of these two patents are incorporated herein by reference. In the preferred embodiment of the invention, an organic or inorganic microparticle is added to the slurry after the introduction of the shear stress. Preferably, the organic microparticle is an anionic polymer of average molecular weight such as the copolymers of acrylic acid described in U.S. Patent No. 5,098,520, the disclosure of which is incorporated herein by reference, or anionic sulfonated polymers, medium molecular weight such as those described in U.S. Patent No. 5,185,062, the disclosure of which is incorporated herein by reference. The inorganic microparticle can be selected preferably from between bentonite and silica sol. According to the invention, the dispersion polymer used to treat the slurry for paper making, cellulosic can furthermore be prepared from a mixture of water-soluble monomer containing at least 5 mol% of a cationic monomer represented by the general formula (I): R, wherein Ri is H or CH 3; R2 and R3 are each an alkyl group having 1 to 2 carbon atoms; i is an oxygen atom or NH; Bi is an alkyl group having 2 to 4 carbon atoms or a hydroxypropyl group and Xi is a counter anion. The above water-soluble monomer mixture is soluble in the aqueous solution of the polyvalent anionic salt. The polymer generated from the monomer mixture is, however, insoluble in the aqueous, polyvalent, anionic salt solution. The polymer of the monomer mixture can also be used as the seed polymer. The seed polymer is described in detail below. The above cationic monomer represented by the general formula (I) is preferably a quaternary ammonium salt obtained by the reaction of methyl chloride or benzyl chloride and dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminohydroxypropyl acrylate, dimethylaminopropyl acrylamide, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and dimethylaminopropyl methacrylamide.

The concentration of the monomers mentioned above in the polymerization reaction mixture is suitably in the range of 1.0 to 30% by weight for the quaternary ammonium salt of methyl chloride. Preferably, the concentration is from about 10 to about 20% by weight. For the quaternary ammonium salts of benzyl chloride, the concentration in the polymerization reaction mixture is suitably in the range of about 1.0 to about 35% by weight. Preferably, the concentration is from about 10 to about 20% by weight. The monomers copolymerized with the cationic monomer are represented by the general formula (I), include acrylamide, methacrylamide and the cationic monomers represented by the general formula (II): R * where R4 is H or CH; R5 and e are each an alkyl group having 1 to 2 carbon atoms; A7 is H or an alkyl group having 1 to 2 carbon atoms; A2 is an oxygen atom or NH; B2 is an alkyl group having 2 to 4 carbon atoms or a hydroxypropyl group and X2 is a counter anion. Preferred monomers represented by formula (II) include the ammonium salts of dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminopropyl acrylamide and dimethylhydroxypropyl acrylate, dimethyl aminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylamide, diethylaminopropyl methacrylamide and dimethylhydroxypropyl methacrylate as well as the methylated and ethylated quaternary salts. Among the most preferable cationic monomers represented by the general formula (II) are the methylated quaternary salts and salts of dialkylaminoethyl acrylate and dialkylaminoethyl methacrylate. The polyvalent anionic salt to be incorporated in the aqueous solution according to the present invention, is suitably a sulfate, a phosphate or a mixture thereof. Preferable salts include ammonium sulfate, sodium sulfate, manganese sulfate, ammonium sulfate, ammonium acid phosphate, sodium acid phosphate and potassium hydrogen phosphate. In the present invention, these salts may each be used as an aqueous solution thereof having a concentration of 15% or greater. A dispersant is present in the aqueous, anionic salt solution in which the polymerization of the above monomers occurs. The dispersant is a cationic polymer of high molecular weight, soluble in water. The dispersant is soluble in the solution of the harassment salt, mentioned above. The dispersant is preferably used in an amount of from 1 to 10% by weight based on the total weight of the monomers. The dispersant is composed of 20 mol% or more of cationic monomer units represented by the formula (II). Preferably, the% in residual mole is acrylamide or methacrylamide. The performance of the dispersant is not greatly affected by molecular weight. However, the molecular weight of the dispersant is preferably in the range of 10,000 to 10,000,000 daltons. According to one embodiment of the invention, a multifunctional alcohol such as glycerin or polyethylene glycol is co-existent in the polymerization system. The deposition of the fine particles is carried out gently in the presence of these alcohols. For the polymerizations, a usual, water-soluble, radical-forming agent may be employed, but preferably water-soluble azo compounds such as 2,2'-azobis (2-amidinopropane) hydrochloride and 2, 2-hydrochloride are used. '-azobis (N, N' -dimethylenisobutylamine). According to one embodiment of the invention, a seed polymer is added before the beginning of the polymerization of the above monomers for the purpose of obtaining a fine dispersion. The seed polymer is a cationic polymer soluble in water, insoluble in the aqueous solution of the polyvalent anionic salt. The seed polymer is preferably a polymer prepared from the above onomeric mixture by the process described herein. However, the monomer composition of the seed polymer does not always need to be equal to that of the water-soluble cationic polymer formed during the polymerization. However, similar to the water-soluble polymer formed during the polymerization, the seed polymer must contain at least 5 mole percent of cationic monomer units represented by the general formula (I). According to one embodiment of the invention, the seed polymer using in a polymerization reaction is the water soluble polymer prepared in a previous reaction which uses the same monomer mixture.

Eg emplos The following examples are presented to describe preferred embodiments and utilities of the invention and are not intended to limit the invention unless otherwise stated in the claims appended thereto. In the following examples, the common terms used completely have the following meanings.

Microparticle A (colloidal silica) Silica dispersed in water with a particle size of 4 nm.

Microparticle B Acrylic acid copolymer Microparticle C (bentonite) Hydrated suspension of bentonite powder in water.

Polymer dispersion polymer A 10% mol DMAEA.BCQ RSV 19.6 dl / g Polymer B 10% mol DMAEA.MCQ RSV 21.4 dl / g Polymer C 20% mol DMAEA.MCQ RSV 27.6 dl / g Latex Polymer Polymer D 10% in mol DMAEA.MCQ RSV 19.7 dl / g The Reduced Specific Viscosity (RSV) was measured at a concentration of 0.045% polymer in a solution of 0.125M NaN03 solution.

Test in Pitcher of Britt The Pitcher Test of Britt used in the Examples 1 to 3 used a Dynamic Drainage Jug Britt CF developed by K. W. Britt of the New York State University, which generally consists of a top chamber of approximately 1 liter capacity and a bottom drainage chamber, the chamber is separated by a support screen and a drain screen. Subsequently the drainage chamber is a flexible tube that extends downwards equipped with a stopper or clamp for closing. The upper chamber is provided with a high-power, high-speed motor equipped with a 3-inch (5.8 cm) (2-inch) impeller to create controlled shear conditions in the upper chamber. The test was conducted by placing the diluted pulp in the upper chamber and then attaching the diluted pulp to the following sequence: Time Action 0 seconds Start the agitation with shear at 750 rpm, (add starch if necessary).

Add the cationic polymer, seconds increase the speed to 2000 rpm. 40 Reduce the agitation with second cutting effort at 750 rpm. 50 Add the microparticle. seconds 60 Open the plug or clamp of the tube for seconds to start the drain or drain, and continue draining or draining for 30 seconds The material drained in this way from Britt's jar (the "filtrate") is collected and diluted with water to a quarter of its initial volume. Then the turbidity of such diluted filtrate, measured in Formazin Turbidity Units or FTU 's, is determined. The turbidity of such filtration is inversely proportional to the retention performance of papermaking; the lowest turbidity volume, the highest is the retention of the filler and / or finely ground materials. The turbidity values were determined using a Hach spectrophotometer, model DR2000. The turbidity values (in FTU) that were determined were converted to values (Improvement in Percent) using the formula: Improvement in Percent = 100 X (Turbiedadu - Turbiedadt) / Turbiedadu where Turbidity, is the result of turbidity reading for the model for which no polymer or microparticle, and where Turbiedadt is the result of turbidity reading of the test using polymer, or polymer and microparticle.

Filtration Test The filtration tests used in the Examples 1 to 8 measured the proportion of drainage or drainage (removal of water) of the diluted pulp, of test subjected to the various chemical treatments. A filtration cell was used, mounted upwards in a house or pavilion. The capacity of this cell is approximately 220 milliliters. A 200 mesh drain or drain screen (76 μg screen with 8% opening) served as the filter medium. The diluted pulp was filtered by gravity. The filtrate was collected in a cup placed on a weight balance after the cell. This balance was interconnected like a computer so that the displayed weight was recorded continuously over time. The computer automatically recorded the change in weight over time. The cellulose-diluted pulp was treated in the Britt jar mentioned above. Diluted pulp, treated was transferred to the cell and filtered to completion. The filtering collection ratio is an indication of drainage performance; If the proportion of filtration collection is higher, the improvement in drainage is higher.

Paste Diluted Test Bin Paste Diluted Alkaline Test Bin The paste or solution is a dilute cellulose binder used in Examples 1 to 3 and 8 was comprised of 70 wt% fiber and 30 wt% filler, was diluted to a Total consistency of 0.5% with water formulation. The fiber was a 60/40 weight blend of bleached kraft hardwood and bleached kraft softwood, whipped separately to a Canadian Refined value range of 320 to 360 C.F.S. The filler a commercial calcium carbonate, provided in dry form. The formulation water contained calcium hardness of 60 ppm (added as CaCl2), and magnesium hardness of 18 ppm (added as MgSO4) and bicarbonate alkalinity of 134 ppm (added as NaHCO3). The pH of the thin, final pulp was pH 7.2.

Acidic Test Bin Pulp The pulp or cellulosic bulk solution used in Examples 4 to 5 was comprised of 93 weight percent fiber and 7 weight percent filler, diluted to a total consistency of 0.54 percent with plain water. formulation. The fiber was a mixture of 50/50 by weight bleached kraft hardwood and bleached kraft softwood, whipped separately to a range of Canadian Refined value of 320 to 360 C.F.S. The fillers were clay as was predisposed kaolin or titanium dioxide, commercially provided in dry form. The pH was adjusted to pH 4.00 using dilute sulfuric acid, then alum (0.005% final slurry) was added, and rosin sizing agent (0.0025% by weight of final slurry). The formulation water contained calcium hardness of 60 ppm (added as CaCl2), magnesium hardness of 18 ppm (added as MgSO4) and bicarbonate alkalinity of 134 ppm (added as NaHCO3).

Test Paper, Coated, Corrugated Pulp Pasta The pulp used in the Examples 6 and 7 was obtained as a thick pulp (consistency of 4.11%) of a paper mill. This was a mixture of OCC, newspaper and cardboard for boxes. This was diluted to a total consistency of 0.8% with formulation water containing calcium hardness of 60 ppm (added as CaCl?) Magnesium hardness of 18 ppm (added as MgSO) and bicarbonate alkalinity of 134 ppm (added as NaHCO3) ). The final pH of the thin pulp was pH 6.5. The percent of ash wood of the thin pulp was 7.3% by weight.

EXAMPLE 1 Using the dilute pulp of the alkaline test described above, the Britt jar test, also described above, was used to determine the retention performances of Polymer A dispersion compared to Polymer D inverse emulsion, with the microparticle A like the microparticle. In each test, cationic, potato starch was applied to the diluted test pulp in the amount of 4.54 kg / ton (10 lb / ton) dry weight of slurry solids. The various tested programs are shown later in Table 1. The results of the test were reported in Table 1 below as the turbidity values of the diluted filtrate (FTU) and (Improvement in Percent), as more recently defined, for each of the programs tested. The performance of drainage or drainage of these programs was measured by the same alkaline supply that uses the filtration test described above. In each test starch, the diluted test pulp was charged in the amount of 4.54 kg / ton (10 lb / ton) dry weight of the slurry solids. The results are shown for each of the programs tested in Figure 1 as graphs of the filtering weight collected against time.

Example 2 Using the diluted pulp of the alkaline test, the Britt jar test, also described above, was used to determine the retention performances of the Polymer B dispersion compared to the Reverse emulsion Polymer D, with microparticle A as the microparticle. In each test, cationic, potato starch was applied to the diluted test pulp in the amount of 4.54 kg / ton (10 lb / ton) dry weight of the slurry solids. The various programs tested are shown later in Table 2. The test results were reported in Table 2 below as the turbidity values of the diluted filtrate (FTU) and (Improvement in Percent), as defined more recently, for each one of the tested programs. The drainage or drainage performance of these programs was measured for the alkaline supply using the filtration test described above. In each test starch, the diluted test pulp was charged in the amount of 4.54 kg / ton (10 lb / ton) dry weight of the slurry solids. The results are shown for each of the programs tested in Figure 2 as graphs of the weight of the filtrate collected against time.

Table I Retention Tests with Pitcher of Britt Alkaline Supply Polymer Dose Dosage of Mi- Turbidity Improvement Polymer particle (FTU to in Per kg / ton kg / ton cent (lb / ton) (lb / ton) model 0 0 359.5 A .725 0 289 20 (1.6) A .725 2 84 77 (1.6) D .725 0 291 19 (1.6) D .725 2 162 55 (1.6) Table II Pitcher Retention Tests of Britt Alkaline Water Supply No. Polymer Dose Mi- Turbidity Dose Improvement - Polyparticulate Polymer (FTU) to in Per kg / ton kg / ton cent (lb / ton) (lb / ton) white 0 0 359.5 1 B .725 0 252 30 (1.6 ) 2 B .725 2 74 79 (1.6) 3 D .725 0 291 19 (1.6) 4 D .725 2 162 55 (1.6) Example 3 Using the diluted pulp from the alkaline test described above, the Britt jar test, also described above, was used to determine the retention performances of Polymer C dispersion compared to Polymer D inverse emulsion, with microparticle A like the microparticle. In each test, the cationic potato starch was loaded to the test pulp in the amount of 4.54 kg / ton (10 lb / ton) dry weight of the slurry solids. The various programs tested are shown later in Table 3. The test results are reported in Table 3 below as the turbidity values of the diluted filtrate (FTU) and (Improvement in Percent), as defined more recently, for each one of the tested programs.

Table III Pit Retention Tests of Britt Alkaline Water Supply No. Polymer Dose Dosage Mi-Turbidity Improvement Polymer particle (FTU to in Per kg / ton kg / ton cent (lb / ton) (lb / ton) model 0 0 359.5 1 C .725 0 266 26 (1.6) 2 C .725 2 120 67 (1.6) 3 D .725 0 291 19 (1.6) 4 D .725 2 162 55 (1.6) EXAMPLE 4 Using the diluted pulp from the acid test described above, the filtration test, also described above, was employed to determine the drainage or drainage performances of the dispersion polymer A compared to the reverse emulsion polymer D, with microparticle A as the microparticle. The results are shown for each of the programs tested in Figure 3 as graphs of the weight of the filtrate collected against time.

Example 5 Using the acid test diluted pulp described above, the filtration test, also described above, was used to determine drainage or drainage performances of Dispersion Polymer A compared to Reverse Emulsion Polymer D, with microparticle B like the microparticle. The results are shown for each of the programs tested in Figure 4 as graphs of the weight of the filtrate collected against time.

EXAMPLE 6 Using the coated, corrugated, diluted test pulp described above, the filtration test, also described above, was used to determine the drainage or drainage performances of Dispersion Polymer A, with microparticle A as the microparticle. The results are shown for each of the programs tested in Figure 5 as graphs of the weight of the filtrate collected against time.

Example 7 Using the coated, corrugated, diluted test pulp described above, the filtration test, also described above, was used to determine the drainage or drainage performances of Dispersion Polymer A, with microparticle B as the microparticle. The results are shown for each of the programs tested in Figure 6 as graphs of the weight of the filtrate collected against time.

Figure 8 Using the alkaline test diluted pulp described above, the filtration test, also described above, was used to determine the drainage or drainage performances of Polymer A dispersion compared to Polymer D inverse emulsion, with microparticle C as the microparticle. In each test, the cationic potato starch was loaded to the diluted pulp of the test in the amount of 4.54 kg / ton (10 lb / ton) dry weight of the slurry solids. The results are shown for each of the programs tested in Figure 7 as graphs of the weight of the filtrate collected against time. Changes can be made in the composition, operation and arrangement of the method of the present invention described herein without departing from the concept and scope of the invention as defined in the following claims: It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following claims is claimed as property.

Claims (10)

1. A process for the manufacture of paper, characterized in that it comprises forming a slurry for the production of paper, cellulose, water, hold the slurry to one or more stages of shear, add a mineral filler to the slurry before at least one of the steps with shear stress, add to the slurry after the addition of the mineral filler and before at least one of the shear stages an effective amount of a dispersion, cationic polymer selected from the group consisting of copolymers of acrylamide and quaternary salt of dimethylaminoethyl acrylate methyl chloride, quaternary salt of dimethylaminoethyl methacrylate methyl chloride, quaternary salt of dimethylaminomethyl acrylate benzyl chloride, quaternary salt of dimethylaminoethyl methacrylate benzyl chloride and diallyldimethylammonium chloride: to subject the thick suspension to shear stress; adding a microparticle selected from the group consisting of a copolymer of acrylic acid, bentonite and silica sol; drain the slurry to form a sheet; and dry the sheet to form a sheet of paper.

2. The process according to claim 1, characterized in that the dispersion polymer has a molecular weight from about 10,000 to 10,000,000 daltons.

3. The process according to claim 1, characterized in that the slurry is drained in a screen for making paper and is pumped to the screen site to manufacture paper before draining or draining.

4. The process according to claim 1, characterized in that the slurry is selected from the group consisting of a slurry of acid pulp, slurry of alkaline chemical pulp, thick slurry of thermomechanical pulp, slurry of pulp. mechanical, thick suspension of recycled pulp and thick slurry of defibrated wood pulp.

5. The process according to claim 1, characterized in that mineral filler is selected from the group consisting of titanium dioxide, clay and calcium alkali carbonate talc.

6. The process according to claim 1, characterized in that the mineral filler is added to the slurry in an amount from about 2 to about 50 parts per hundred parts by weight of the dry pulp contained in the slurry.

7. The process according to claim 1, characterized in that the concentration of the quaternary salt of methyl chloride is from about 1.0 to about 30 mole percent.

8. The process according to claim 7, characterized in that the concentration of the quaternary salt of methyl chloride is from about 10 to about 20 mole percent.

9. The process according to claim 1, characterized in that the concentration of the quaternary salt of benzyl chloride is from about 1.0 to about 35 mole percent.

10. The process according to claim 9, characterized in that the concentration of the quaternary salt of benzyl chloride is from about 10 to about 20 mole percent. SUMMARY OF THE INVENTION The claimed invention comprises a process for making paper comprising forming a slurry to make paper, cellulosic, aqueous, holding the slurry to one or more stages of shear, adding a mineral filler to the slurry before at least one of the shear stages, adding to the slurry after the addition of the mineral filler and before at least one of the shear stages, an effective amount of a dispersion polymer selected from the group consisting of acrylamide and salt copolymers Quaternary methyl chloride of dimethylaminoethyl acrylate (DMAEA.MCQ), quaternary salt of methyl chloride of dimethylaminoethyl methacrylate (DMAEM.MCQ), quaternary salt of dimethylaminoethyl acrylate benzyl chloride (DMAEA.BCQ) and quaternary salt of dimethylaminoethyl methacrylate benzyl chloride (DMAEM.BCQ) and chloride of diallyldimethylammonium (DADMAC), the slurry is subjected to shear stress, adding a microparticle selected from the group consisting of organic substances such as copolymers of polyacrylic acid, inorganic substances such as bentonite and silica sol, draining the slurry to form a sheet, and dry the sheet to form a sheet of paper.