EP0893538A1 - Use of blends of dispersion polymers and coagulants for papermaking - Google Patents
Use of blends of dispersion polymers and coagulants for papermaking Download PDFInfo
- Publication number
- EP0893538A1 EP0893538A1 EP97112514A EP97112514A EP0893538A1 EP 0893538 A1 EP0893538 A1 EP 0893538A1 EP 97112514 A EP97112514 A EP 97112514A EP 97112514 A EP97112514 A EP 97112514A EP 0893538 A1 EP0893538 A1 EP 0893538A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- polymer
- slurry
- broke
- blend
- carbon atoms
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
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Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/20—Macromolecular organic compounds
- D21H17/33—Synthetic macromolecular compounds
- D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
- D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
- D21H17/45—Nitrogen-containing groups
- D21H17/455—Nitrogen-containing groups comprising tertiary amine or being at least partially quaternised
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/06—Paper forming aids
- D21H21/10—Retention agents or drainage improvers
Definitions
- the invention relates to the field of papermaking, and, in particular, to an improved papermaking process utilizing hydrophobic dispersion polymers to increase retention of fibers onto the paper sheet.
- aqueous cellulosic suspension or slurry is formed into a paper sheet.
- the cellulosic slurry is generally diluted to a consistency (percent dry weight of solids in the slurry) of less than 1 percent, and often below 0.5 percent, ahead of the paper machine, while the finished sheet must have less than 6 weight percent water.
- a consistency percent dry weight of solids in the slurry
- a papermaking furnish contains particles that range in size from about the 2 to 3 millimeter size of cellulosic fibers to fillers measuring only a few microns. Within this range are cellulosic fines, mineral fillers (employed to increase opacity, brightness and other paper characteristics) and other small particles that generally, without the inclusion of one or more retention aids, would pass through the spaces (pores) between the cellulosic fibers in the fiber mat being formed.
- a coagulant/flocculant system added ahead of the paper machine.
- a coagulant for instance a low molecular weight cationic synthetic polymer or a cationic starch, which coagulant generally reduces the negative surface charges present on the particles in the furnish, particularly cellulosic fines and mineral fillers, and thereby agglomerates such particles.
- the coagulant is followed by the addition of a flocculant.
- the flocculant is generally a high molecular weight anionic synthetic polymer which bridges the particles and/or agglomerates, from one surface to another, binding the particles into large agglomerates.
- the presence of such large agglomerates in the furnish increases retention.
- the agglomerates are filtered out of the water onto the fiber web, where unagglomerated particles otherwise would to a great extent pass.
- the shearing generally is provided by one or more of the cleaning, mixing and pumping stages of the papermaking process, and the shearing breaks down the large flocs formed by the high molecular weight polymer into microflocs, and further agglomeration then ensues 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 web by charge neutralization and adsorption of smaller agglomerates. This system is described in U.S. Patent No. 4,388,150, inventors Sunden et all, issued June 14, 1983.
- paper or paper board is generally made from a suspension or slurry of cellulosic material in an aqueous medium, which slurry is subjected to one or more shear stages, which stages generally are a clearing stage, a mixing stage and a pumping stage, and thereafter the suspension is drained to form a sheet, which sheet is then dried to the desired, and generally low, water concentration.
- the cationic polymer generally has a molecular weight of at least 500,000, and preferably the molecular weight is above 1,000,000 and may be above 5,000,000, for instance in the range of from 10 to 30 million or higher.
- the cationic polymer is substantially linear; it may be wholly linear or it can be slightly cross linked provided its structure is still substantially linear in comparison with the globular structure of cationic starch.
- the cationic polymer has a relatively high charge density of for instance about 0.2 and preferably at least about 0.35, and most preferably about 0.4 to 2.5 or higher, equivalents of cationic nitrogen per kilogram of polymer.
- the amount of cationic monomer will normally be above 2 mole percent and usually above 5 mole percent, and preferably above 10 mole percent, based on the total moles of monomer used in forming the polymer.
- the amount of the cationic polymer employed in the process, in the absence of any substantial amount of cationic binder, is typically at least 0.3 percent based on dry weight of the slurry, and preferably 0.6 percent in the substantial absence of cationic binder and 0.5 percent in the presence of cationic binder, same basis, which is from 1.1 to 10 times, and usually 3 to 6 times, the amount of cationic polymer that would be used in conventional (dual polymer) processes, and hence is considered "an excess amount" of cationic polymer.
- the cationic polymer is preferably added to thin stock, preferably cellulosic slurry having a consistency of 2 percent or less, and at most 3 percent.
- the cationic polymer may be added to prediluted slurry, or may be added to a slurry together with the dilution water.
- broke In the pulp and papermaking industry, the fraction of paper products which do not meet minimum commercial specifications and therefore cannot be sold is called broke.
- the broke which usually comprises the waste or trimming from the formed web, is a valuable source of fibers, and is returned for reuse in a papermaking operation at the same or other mill.
- the broke derived from paper which contains coating is referred as "Coated Broke”. Coating is applied to paper to improve surface smoothness which positively influences printability, and, in some cases, to provide a uniform, bright, opaque layer to cover 'unattractive' base stock. Mills which make use of a relative high proportion of coated broke in the furnish are confronted with several problems due to the presence of the coating in their recycled furnish.
- coated materials contained on coated broke may account for ten (10) to about forty (40) weight percent of the total solids in the paper furnish.
- 80 to 90% of the dry formulation weight of coating is composed of pigments, and 5 to 20% of binders.
- Coating formulations often contain a large variety of components and are customized to meet stringent requirements with respect to both the paper coating itself and the handling properties of the coating dispersion.
- Pigments typically used in paper coating include various types of clays, various types of calcium carbonates, and titanium dioxide.
- Other types of white pigments include satin white, barium sulfate, zinc oxide, talc, plastic pigments, alumina trihydrate, and titanium dioxide extenders.
- Organic or inorganic colored pigments are also used in some cases.
- Coating binders fall into three classifications: starches, proteins and synthetics. Protein binders are either casein, soy extract, or animal glues. Synthetic binders are mainly latexes based on vinyl alcohol, styrene butadiene, vinyl acetate and acrylic polymers.
- Mills which make use of coated broke in their furnish experience problems of sticky deposits originating from binder materials in combination with pigments and fillers. These deposits, often referred as "white pitch", can be found throughout the wet end, the press section, and the dryer section of a paper mill. They may cause operational problems such as holes or specks in the paper, felt filling, paper machine and coater breaks, and buildup of deposits on vacuum boxes, drying cylinders and calendar rolls. The consequence is frequent machine downtime and loss of runnability, and occasionally also loss of efficiency of chemical additives such as retention aids.
- Coagulants also act to neutralize the effects of dispersing agents from the coating, which are detrimental to retention.
- coagulants help retain the fine coating pigments, resulting in improved ash retention.
- Treatment of coated broke by coagulants is presumed to be based on a charge neutralization mechanism and is often described as broke cationization. However, it has been shown that other mechanisms of aggregation, such as charge patch mechanism and bridging, may play a role in determining polymer activity.
- An improved papermaking process comprising forming an aqueous cellulosic papermaking slurry and adding a blend of a water-soluble dispersion polymer and a coagulant to the slurry to increase retention and/or drainage is disclosed.
- the water-soluble polymer is formed by polymerizing a water-soluble mixture which comprises: (a) a first cationic monomer represented by the following formula (I): wherein R 1 is H or CH 3 each of R 2 and R 3 is an alkyl group having 1 to 3 carbon atoms: A is an oxygen atom or NH: B is an alkylene group of 2 to 4 carbon atoms or a hydroxypropylene group: and X - is an anionic counterion, and/or a second cationic monomer represented by the following general formula (II): wherein R 4 is H or CH 3 : each of R 5 and R 6 is an alkyl group having 1 to 2 carbon atoms: R 7 is H or an alkyl group of 1 to 2 carbon
- blended composition may also be applied to the treatment of wastepaper furnish containing adhesives and deinked fiber.
- the blend contains from 5 to 95 weight % dispersion polymer as product.
- the most preferred blends contain 25 to 75 weight % dispersion polymer as product, although the weight % of dispersion polymer contained in the blend which is efficient to treat the papermaking slurry depends on the nature of the slurry itself.
- the blend is added to the slurry in an amount of from about 0.1 kg product per ton of total broke solids to about 5 kg product per ton of total broke solids.
- the effective treatment rages are between 0.25 kg product per ton of total slurry solids to about 3 kg per ton, although the treatment level demand for the blends can vary with the type of slurry being treated.
- the dispersion polymer and coagulant are blended as concentrated products prior to diluting to use levels and adding to the slurry.
- the dispersion polymer and coagulant may be diluted separately and then added to the slurry.
- the coagulants of the invention are preferably selected from the group consisting of epichlorohydrin dimethylamine, diallyldimethyl ammonium chloride, polyaluminum chloride, alum, polyethylenimine, dicyandiamide, ethylene dichloride ammonia and mixtures thereof.
- Coated broke slurry was prepared in the laboratory from dry broke pulped in Synthetic Chicago Tap Water # 13 for 1 hour and 45 minutes by using a high consistency pulper, and successively disintegrated in a standard disintegrator for 10000 to 45000 revolutions according to the type of broke.
- RSV/IV Reduced specific viscosity/intrinsic viscosity measurements were carried out by capillary viscosimetry under standard conditions (0.125 M NaNO 3 , 30°C,).
- RSV is the polymer reduced specific viscosity at 0.045 % polymer weight.
- IV of the polymer is the intercept of the best line calculated from RSV points at three different polymer weight concentrations.
- Viscosity of the blends was calculated on the basis of percent weight of dispersion polymer present in the blend. Such a calculation allows measurement of viscosity changes that the dispersion polymer undergoes upon its blending with the coagulant.
- Polymers were diluted to 0.2-0.4% product for activity testing. Polymer activity was tested in wet coated broke slurry collected at the paper mill or in coated broke slurry prepared in the laboratory from dry broke as outlined above. A simple turbidity test used to evaluate polymer activity. To 200 ml of broke in a 400-ml beaker, stirred at 500 rpm by using a Britt Jar mixer, blends of a dispersion polymer and solution polymer or individual components were added at 10 seconds. In any case, stirring was stopped at 30 seconds, and the mixture was filtered through a 100-mesh sieve to the same volume of filtrate each time. By this method, retention of coated broke particles is a result of polymer activity and not filtration by the filter medium.
- the filtrate turbidity was measured by a standard turbidity meter (2100 N Turbidimeter by Hach Company) calibrated by using Formazin Primary Standard as suggested by the manufacturer. Retention was expressed in terms of % turbidity reduction of the filtrate from broke with no polymer treatment (blank).
- the viscosity of polymer B varies when this polymer is present in blends with polymer A. Therefore, the viscosity data suggest the existence of specific interactions between premixed polymer A and dispersion polymer B. These interactions may explain the enhancement of retention activity observed for the blend in comparison with the retention activities produced by the two components added at the same time but separately to the broke.
- Polymers A, F and G were tested on fresh wet broke used at the mill immediately after its collection.
- polymer G which is a blend of the coagulant A and dispersion polymer F, has efficiency and effectiveness considerably higher than those of the single components of the blend, polymers A and F.
- the polymers in the example are calculated as product weight, and their dosage is based on dry weight of coated broke.
- the viscosities of the dispersion polymer which has been blended with polymer A is different from that of the dispersion polymer alone. (Table II) This change in viscosity indicates the presence of specific interactions between the coagulant and the dispersion polymer. These interactions may explain the retention activity benefits obtained by using the blends over the single products alone.
- Polymer A was an EPI-DMA solution polymer
- polymer B was a 90/10 AcAm/DMAEA ⁇ BCQ dispersion polymer
- polymer H was a 50/50 blend of polymer A and B
- Polymer H and J had the same composition but differ in the method of preparation.
- Polymer H was prepared by mixing polymer A and B as concentrated products. This mixture was diluted to a working concentration of 0.285 wt % before testing.
- Polymer J was prepared by mixing diluted solutions of polymer A and polymer B at 0.285 wt %. Polymers H and J had the same activity. Both products outperformed their single Components.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Paper (AREA)
Abstract
Description
- Polymer A:
- EPI-DMA solution polymer
- Polymer B:
- 90/10 AcAm/DMAEA·BCQ
- Polymer C:
- 50/50 blend polymer A/polymer B
- Polymer D:
- 25/75 blend polymer A/polymer B
- Polymer E:
- 75/25 blend polymer A/polymer B
Claims (6)
- A papermaking process comprising:forming an aqueous cellulosic papermaking slurry;adding a blend of:a water-soluble dispersion polymer, the water-soluble polymer being formed by polymerizing a water-soluble mixture which comprises: (a) a first cationic monomer represented by the following formula (I): wherein R1 is H or CH3 each of R2 and R3 is an alkyl group having 1 to 3 carbon atoms; A is an oxygen atom or NH; B is an alkylene group of 2 to 4 carbon atoms or a hydroxypropylene group; and X- is an anionic counterion, and/or a second cationic monomer represented by the following general formula (II): wherein R4 is H or CH3; each of R5 and R6 is an alkyl group having 1 to 2 carbon atoms; R7 is H or an alkyl group of 1 to 2 carbon atoms; A is an oxygen atom or NH; B is an alkylene group of 2 to 4 carbon atoms or a hydroxypropylene group; and X- is an anionic counterion; and (b) (meth)acrylamide in an aqueous solution of a polyvalent anion salt;
wherein the polymerization is carried out in the presence of either an organic high-molecular weight multivalent cation comprising a water-soluble polymer containing at least one monomer of formula (II) or an alkyl ester of acrylic acid; anda cationic coagulant;draining the slurry to form a sheet; anddrying the sheet. - The method of Claim 1 wherein the blend contains from 5 to 95 weight % dispersion polymer as product.
- The method of Claim 2 wherein the blend contains 25 to 75 weight % dispersion polymer as product.
- The method of Claim 1 wherein the blend is added to the coated broke slurry in a amount of from about 0.1 kilogram product per ton of total broke solids to about 5.0 kilogram product per ton of total broke solids.
- The method of Claim 4 wherein the blend is added to the coated broke slurry in a amount of from about 0.25 kg product per ton of total broke solids to about 3.0 kg per ton of total broke solids.
- The method of Claim 1 wherein the cationic coagulant is selected from the group consisting of epichlorohydrin dimethylamine, diallyldimethyl ammonium chloride, polyaluminum chloride, alum, polyethylenimine, dicyandiamide, ethylene dichloride ammonia and mixtures thereof.
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/675,134 US5837100A (en) | 1996-07-03 | 1996-07-03 | Use of blends of dispersion polymers and coagulants for coated broke treatment |
CA002210776A CA2210776A1 (en) | 1996-07-03 | 1997-07-18 | Use of blends of dispersion polymers and coagulants for coated broke treatment |
EP97112514A EP0893538A1 (en) | 1996-07-03 | 1997-07-22 | Use of blends of dispersion polymers and coagulants for papermaking |
NO973547A NO307975B1 (en) | 1996-07-03 | 1997-08-01 | Method of making paper |
BR9704355A BR9704355A (en) | 1996-07-03 | 1997-08-13 | Paper production process |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/675,134 US5837100A (en) | 1996-07-03 | 1996-07-03 | Use of blends of dispersion polymers and coagulants for coated broke treatment |
CA002210776A CA2210776A1 (en) | 1996-07-03 | 1997-07-18 | Use of blends of dispersion polymers and coagulants for coated broke treatment |
AU29426/97A AU744781B2 (en) | 1997-07-22 | 1997-07-22 | Use of blends of dispersion polymers and coagulants for coated broke treatment |
EP97112514A EP0893538A1 (en) | 1996-07-03 | 1997-07-22 | Use of blends of dispersion polymers and coagulants for papermaking |
NO973547A NO307975B1 (en) | 1996-07-03 | 1997-08-01 | Method of making paper |
BR9704355A BR9704355A (en) | 1996-07-03 | 1997-08-13 | Paper production process |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0893538A1 true EP0893538A1 (en) | 1999-01-27 |
Family
ID=27542636
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97112514A Ceased EP0893538A1 (en) | 1996-07-03 | 1997-07-22 | Use of blends of dispersion polymers and coagulants for papermaking |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0893538A1 (en) |
BR (1) | BR9704355A (en) |
CA (1) | CA2210776A1 (en) |
NO (1) | NO307975B1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4388150A (en) * | 1980-05-28 | 1983-06-14 | Eka Aktiebolag | Papermaking and products made thereby |
JPS6215251A (en) * | 1985-07-15 | 1987-01-23 | Kyoritsu Yuki Kogyo Kenkyusho:Kk | Production of liquid dispersion of water-soluble cationic polymer |
US4753710A (en) * | 1986-01-29 | 1988-06-28 | Allied Colloids Limited | Production of paper and paperboard |
US5466338A (en) * | 1993-11-17 | 1995-11-14 | Nalco Chemical Company | Use of dispersion polymers for coated broke treatment |
-
1997
- 1997-07-18 CA CA002210776A patent/CA2210776A1/en not_active Abandoned
- 1997-07-22 EP EP97112514A patent/EP0893538A1/en not_active Ceased
- 1997-08-01 NO NO973547A patent/NO307975B1/en not_active IP Right Cessation
- 1997-08-13 BR BR9704355A patent/BR9704355A/en active Search and Examination
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4388150A (en) * | 1980-05-28 | 1983-06-14 | Eka Aktiebolag | Papermaking and products made thereby |
JPS6215251A (en) * | 1985-07-15 | 1987-01-23 | Kyoritsu Yuki Kogyo Kenkyusho:Kk | Production of liquid dispersion of water-soluble cationic polymer |
US4753710A (en) * | 1986-01-29 | 1988-06-28 | Allied Colloids Limited | Production of paper and paperboard |
US5466338A (en) * | 1993-11-17 | 1995-11-14 | Nalco Chemical Company | Use of dispersion polymers for coated broke treatment |
Non-Patent Citations (1)
Title |
---|
DATABASE WPI Section Ch Week 8709, Derwent World Patents Index; Class A14, AN 87-060570, XP002049350 * |
Also Published As
Publication number | Publication date |
---|---|
BR9704355A (en) | 1999-03-30 |
NO973547L (en) | 1999-02-02 |
CA2210776A1 (en) | 1999-01-18 |
NO973547D0 (en) | 1997-08-01 |
NO307975B1 (en) | 2000-06-26 |
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