CA2340641A1 - Manufacture of paper - Google Patents
Manufacture of paper Download PDFInfo
- Publication number
- CA2340641A1 CA2340641A1 CA002340641A CA2340641A CA2340641A1 CA 2340641 A1 CA2340641 A1 CA 2340641A1 CA 002340641 A CA002340641 A CA 002340641A CA 2340641 A CA2340641 A CA 2340641A CA 2340641 A1 CA2340641 A1 CA 2340641A1
- Authority
- CA
- Canada
- Prior art keywords
- suspension
- starch
- reflocculating
- aqueous
- process according
- 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.)
- Abandoned
Links
- 238000004519 manufacturing process Methods 0.000 title description 4
- 229920002472 Starch Polymers 0.000 claims abstract description 59
- 235000019698 starch Nutrition 0.000 claims abstract description 59
- 239000008107 starch Substances 0.000 claims abstract description 56
- 239000000725 suspension Substances 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 21
- 238000010008 shearing Methods 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 8
- 229920001059 synthetic polymer Polymers 0.000 claims abstract description 7
- 230000003311 flocculating effect Effects 0.000 claims abstract description 4
- 239000007864 aqueous solution Substances 0.000 claims abstract description 3
- 229920005615 natural polymer Polymers 0.000 claims abstract 2
- 230000014759 maintenance of location Effects 0.000 claims description 31
- 239000000203 mixture Substances 0.000 claims description 24
- 239000000463 material Substances 0.000 claims description 16
- 125000000129 anionic group Chemical group 0.000 claims description 13
- 239000006185 dispersion Substances 0.000 claims description 13
- 238000010411 cooking Methods 0.000 claims description 8
- 125000002091 cationic group Chemical group 0.000 claims description 6
- 229920006317 cationic polymer Polymers 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims description 2
- 230000008961 swelling Effects 0.000 claims description 2
- 239000004927 clay Substances 0.000 claims 1
- 239000008119 colloidal silica Substances 0.000 claims 1
- 150000004760 silicates Chemical class 0.000 claims 1
- 239000000440 bentonite Substances 0.000 description 22
- 229910000278 bentonite Inorganic materials 0.000 description 22
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 22
- 239000000123 paper Substances 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 4
- 229920006320 anionic starch Polymers 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 229920001592 potato starch Polymers 0.000 description 4
- 239000002699 waste material Substances 0.000 description 4
- GHCVXTFBVDVFGE-UHFFFAOYSA-N 4-amino-6-chloro-1,3,5-triazin-2-ol Chemical compound NC1=NC(O)=NC(Cl)=N1 GHCVXTFBVDVFGE-UHFFFAOYSA-N 0.000 description 3
- NEHMKBQYUWJMIP-UHFFFAOYSA-N anhydrous methyl chloride Natural products ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229940050176 methyl chloride Drugs 0.000 description 3
- -1 methyl chloride quaternary ammonium salt Chemical class 0.000 description 3
- DPBJAVGHACCNRL-UHFFFAOYSA-N 2-(dimethylamino)ethyl prop-2-enoate Chemical compound CN(C)CCOC(=O)C=C DPBJAVGHACCNRL-UHFFFAOYSA-N 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- 239000007900 aqueous suspension Substances 0.000 description 2
- 238000005189 flocculation Methods 0.000 description 2
- 230000016615 flocculation Effects 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 240000003183 Manihot esculenta Species 0.000 description 1
- 235000016735 Manihot esculenta subsp esculenta Nutrition 0.000 description 1
- 101100216185 Oryza sativa subsp. japonica AP25 gene Proteins 0.000 description 1
- 244000061456 Solanum tuberosum Species 0.000 description 1
- 235000002595 Solanum tuberosum Nutrition 0.000 description 1
- 241000209140 Triticum Species 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- NJSSICCENMLTKO-HRCBOCMUSA-N [(1r,2s,4r,5r)-3-hydroxy-4-(4-methylphenyl)sulfonyloxy-6,8-dioxabicyclo[3.2.1]octan-2-yl] 4-methylbenzenesulfonate Chemical compound C1=CC(C)=CC=C1S(=O)(=O)O[C@H]1C(O)[C@@H](OS(=O)(=O)C=2C=CC(C)=CC=2)[C@@H]2OC[C@H]1O2 NJSSICCENMLTKO-HRCBOCMUSA-N 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 239000002738 chelating agent Substances 0.000 description 1
- 125000004985 dialkyl amino alkyl group Chemical group 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000011087 paperboard Substances 0.000 description 1
- 239000011236 particulate material Substances 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
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
- D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
- D21H23/02—Processes or apparatus for adding material to the pulp or to the paper characterised by the manner in which substances are added
- D21H23/04—Addition to the pulp; After-treatment of added substances in the pulp
- D21H23/06—Controlling the addition
- D21H23/14—Controlling the addition by selecting point of addition or time of contact between components
-
- 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
-
- 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
- D21H17/21—Macromolecular organic compounds of natural origin; Derivatives thereof
- D21H17/24—Polysaccharides
- D21H17/28—Starch
Landscapes
- Paper (AREA)
Abstract
A process for making paper on a paper-making machine comprising providing a cellulosic thin stock-suspension, flocculating the suspension by adding an aqueous solution of a polymeric retension aid selected from natural and synthetic polymer and thereby forming a flocculated suspension, shearing the flocculated suspension, reflocculating the sheared suspension by adding an aqueous reflocculating suspension, draining the reflocculated suspension through a wire to form a sheet, and drying the sheet, characterised in that substantially fully cooked starch is added to the suspension after the shearing and before the draining.
Description
Manufacture of Paper This invention relates to the production of paper which is strengthened by starch. Various processes for making paper, and for making paper strengthened by starch, are described in, for instance, W095/33096, which is incorporated herein by reference.
Processes which are currently of particular interest in paper making comprise providing a cellufosic thin stock suspension, flocculating this suspension, shearing the flocculated suspension, reflocculating the sheared suspension by adding an aqueous reflocculating composition, draining the suspension through a wire to form a wet sheet, and drying the sheet. The flocculation is generally caused by the use of a natural or synthetic polymeric retention aid and the reflocculation is generally caused by the use of an aqueous suspension of bentonite or other anionic microparticulate material.
It is known to include starch in the final sheet so as to improve the strength.
One conventional treatment comprises applying a solution of substantially fully cooked starch to the sheet before final drying. It is also known to apply partially or wholly uncooked starch in this position and to cook it during the drying. It is also known to include substantially uncooked starch in the aqueous suspension before drainage, for instance as a result of being added with the polymeric retention aid or with the aqueous reflocculating composition. The substantially uncooked starch may have been slightly cooked so as to facilitate its final cooking, but most or all of the cooking is conducted during the drying stage thereby converting the substantially uncooked starch to substantially fully cooked starch in the final sheet.
In the invention, substantially fully cooked starch is added to the suspension after the suspension has been flocculated, and preferably after the flocculated suspension has been sheared. Preferably the aqueous reflocculating composition comprises the substantially fully cooked starch.
The aqueous reflocculating composition preferably comprises an aqueous dispersion of anionic microparticulate material. The substantially fully cooked starch may be precooked to its substantially fully cooked state and then the cooked starch and the anionic microparticulate material may be blended to form the final dispersion containing both. For instance the starch may be cooked and then mixed with an aqueous dispersion of the microparticulate material.
Preferably, however, the reflocculating composition is made by mixing substantially uncooked starch with an aqueous dispersion of the microparticulate material and cooking the starch in that dispersion. If necessary or desirable, the resultant dispersion may then be diluted with water. It seems that cooking the starch in the presence of the microparticulate material generates a particularly desirable structure within the reflocculating composition.
Preferred anionic particulate materials are swelling clays such as silica, colloidal silicic acid and colloidal silicas, polysilicate and polysilicic acid microgels and aluminium modified versions of these, and organic microparticles, for instance all as described in W095133096.
Another reflocculating composition that can be used is an aqueous solution of a polymer which is generally counterionic to the polymeric retention aid which was used for causing the initial flocculation of the cellulosic thin stock suspension, and in particular it can be a material as described in W098129604.
The starch must be fully cooked prior to drainage, and preferably prior to addition to the aqueous celiulosic thin stock suspension, by which we mean that the starch granules must have burst and become substantially fully gelatinised.
Naturally it is usually necessary to maintain the starch under some degree of agitation during cooking, as is conventional.
Preferably substantially no uncooked starch is included in the suspension which is drained, and thus it is not necessary to rely on cooking of the starch during drying of the sheet.
The starches which can be used can be any of the conventional starches such as cationic, anionic or amphoteric starches and can be derived from, for instance, com. wheat, potato or tapioca or may be recovered starch.
In another embodiment of the invention, the aqueous reflocculating composition can contain. as its essential component, merely cooked starch which is sufFciently counterionic to the sheared cellulosic flocs for it to act as a reflocculating composition. In practice the cooked starch which best meets this requirement is usually amphoteric cooked starch.
Processes which are currently of particular interest in paper making comprise providing a cellufosic thin stock suspension, flocculating this suspension, shearing the flocculated suspension, reflocculating the sheared suspension by adding an aqueous reflocculating composition, draining the suspension through a wire to form a wet sheet, and drying the sheet. The flocculation is generally caused by the use of a natural or synthetic polymeric retention aid and the reflocculation is generally caused by the use of an aqueous suspension of bentonite or other anionic microparticulate material.
It is known to include starch in the final sheet so as to improve the strength.
One conventional treatment comprises applying a solution of substantially fully cooked starch to the sheet before final drying. It is also known to apply partially or wholly uncooked starch in this position and to cook it during the drying. It is also known to include substantially uncooked starch in the aqueous suspension before drainage, for instance as a result of being added with the polymeric retention aid or with the aqueous reflocculating composition. The substantially uncooked starch may have been slightly cooked so as to facilitate its final cooking, but most or all of the cooking is conducted during the drying stage thereby converting the substantially uncooked starch to substantially fully cooked starch in the final sheet.
In the invention, substantially fully cooked starch is added to the suspension after the suspension has been flocculated, and preferably after the flocculated suspension has been sheared. Preferably the aqueous reflocculating composition comprises the substantially fully cooked starch.
The aqueous reflocculating composition preferably comprises an aqueous dispersion of anionic microparticulate material. The substantially fully cooked starch may be precooked to its substantially fully cooked state and then the cooked starch and the anionic microparticulate material may be blended to form the final dispersion containing both. For instance the starch may be cooked and then mixed with an aqueous dispersion of the microparticulate material.
Preferably, however, the reflocculating composition is made by mixing substantially uncooked starch with an aqueous dispersion of the microparticulate material and cooking the starch in that dispersion. If necessary or desirable, the resultant dispersion may then be diluted with water. It seems that cooking the starch in the presence of the microparticulate material generates a particularly desirable structure within the reflocculating composition.
Preferred anionic particulate materials are swelling clays such as silica, colloidal silicic acid and colloidal silicas, polysilicate and polysilicic acid microgels and aluminium modified versions of these, and organic microparticles, for instance all as described in W095133096.
Another reflocculating composition that can be used is an aqueous solution of a polymer which is generally counterionic to the polymeric retention aid which was used for causing the initial flocculation of the cellulosic thin stock suspension, and in particular it can be a material as described in W098129604.
The starch must be fully cooked prior to drainage, and preferably prior to addition to the aqueous celiulosic thin stock suspension, by which we mean that the starch granules must have burst and become substantially fully gelatinised.
Naturally it is usually necessary to maintain the starch under some degree of agitation during cooking, as is conventional.
Preferably substantially no uncooked starch is included in the suspension which is drained, and thus it is not necessary to rely on cooking of the starch during drying of the sheet.
The starches which can be used can be any of the conventional starches such as cationic, anionic or amphoteric starches and can be derived from, for instance, com. wheat, potato or tapioca or may be recovered starch.
In another embodiment of the invention, the aqueous reflocculating composition can contain. as its essential component, merely cooked starch which is sufFciently counterionic to the sheared cellulosic flocs for it to act as a reflocculating composition. In practice the cooked starch which best meets this requirement is usually amphoteric cooked starch.
Accordingly, the invention also provides a novel paper making process in which the reflocculation of the sheared suspension is achieved merely by adding cooked amphoteric or other suitable starch, without the customary anionic microparticulate material. Such processes give satisfactory retention and drainage properties despite the absence of the microparticulate material.
All the processes of the invention give improved strength, for instance as indicated by the burst strength.
The amount of starch which is to be added will be selected having regard to the degree of strength that is required and having regard to the other components in the suspension. Generally it is at least 0.5 and usually at least 1 % by weight and can be as much as 10 or 15% by weight, based on the dry weight of the cellulosic thin stock.
The polymeric retention aid which is used can be cationic starch but is generally a synthetic polymer. The synthetic polymer can comprise a combination of !ow and high molecular weight polymers, as is known, but generally the final polymeric retention aid which is added is a synthetic polymer having intrinsic viscosity at least 4dl/g. The synthetic polymer can be non-ionic, anionic or cationic, but is usually cationic. Preferably the retention aid is a synthetic cationic polymer of intrinsic viscosity of at least 4dl/g. Typically the cationic polymers may be copolymers of acrylamide with for instance diallyl dimethyl ammonium chloride or dialkylaminoalkyl (meth) -acrylate or -acrylamide polymers (usually as acid addition or quaternary ammonium salt). Suitable materials are described in, for instance W095133096 and in the documents to which it refers.
Similarly, reference should be made to those documents for a description of suitable cellulosic materials and process steps.
The process can be used to generate any weight of paper, including paper board, and so may be low weight or high weight. The invention is of particular value in relatively low weight materials since it is in these materials that it can be difficult to achieve adequate cooking of uncooked starch during the drying stage. Thus, for instance, the invention is of particular value in the production of sheets of below 150 grams per square metre. but it can also be applied to higher weight sheets and boards.
All the processes of the invention give improved strength, for instance as indicated by the burst strength.
The amount of starch which is to be added will be selected having regard to the degree of strength that is required and having regard to the other components in the suspension. Generally it is at least 0.5 and usually at least 1 % by weight and can be as much as 10 or 15% by weight, based on the dry weight of the cellulosic thin stock.
The polymeric retention aid which is used can be cationic starch but is generally a synthetic polymer. The synthetic polymer can comprise a combination of !ow and high molecular weight polymers, as is known, but generally the final polymeric retention aid which is added is a synthetic polymer having intrinsic viscosity at least 4dl/g. The synthetic polymer can be non-ionic, anionic or cationic, but is usually cationic. Preferably the retention aid is a synthetic cationic polymer of intrinsic viscosity of at least 4dl/g. Typically the cationic polymers may be copolymers of acrylamide with for instance diallyl dimethyl ammonium chloride or dialkylaminoalkyl (meth) -acrylate or -acrylamide polymers (usually as acid addition or quaternary ammonium salt). Suitable materials are described in, for instance W095133096 and in the documents to which it refers.
Similarly, reference should be made to those documents for a description of suitable cellulosic materials and process steps.
The process can be used to generate any weight of paper, including paper board, and so may be low weight or high weight. The invention is of particular value in relatively low weight materials since it is in these materials that it can be difficult to achieve adequate cooking of uncooked starch during the drying stage. Thus, for instance, the invention is of particular value in the production of sheets of below 150 grams per square metre. but it can also be applied to higher weight sheets and boards.
Chelating agent may be incorporated in the reflocculating composition andlor in the aqueous phase in which the starch is to be cooked, if the water is hard.
The following examples illustrate the invention.
WO 00/12819 PCTlEP99/05999 Example 1 110 grams per square metre hand sheet was prepared by flocculating cellulosic thin stock with higher molecular weight water soluble cationic polymer derived from acrylamide and cationic monomer in conventional manner followed by shearing followed by the addition of an aqueous reflocculating composition.
The burst strength (in KPA) depended on the reflocculating composition.
In one series of experiments, the reflocculating composition consisted of an aqueous dispersion of bentonite alone or with anionic potato starch. The burst strength when the bentonite was used alone was 299KPA. The burst strength when the anionic potato starch was cooked in the bentonite dispersion was 352 and the burst strength when the anionic starch was cooked and added after the shearing but before the bentonite was 322.
Example 2 Example 1 was repeated and varying the reflocculating composition. When bentonite was added alone the burst strength was 169. The burst strength when precooked anionic starch was included in the bentonite dispersion was 281. The burst strength when the anionic starch was cooked in the bentonite was 350. The burst strength when the anionic starch was precooked and added after the shearing, but in the absence of any bentonite during the process, was 308.
When amphoteric starch was included and cooked in the bentonite, the burst strength was 271. When amphoteric starch was cooked and added after the shearing stage but without the addition of bentonite then or subsequently good retention was obtained and the burst strength was 379. In this series of experiments the amount of starch was 7% based on fibre.
Example 3 Free drainage test was carried out on a packaging grade paper furnish derived from waste using a copolymer of acryiamide with dimethylaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12d1/g as the retention aid and either bentonite or cooked starch as the reflocculating composition.
For each dose the free drainage was measured in secands for 100m1. 200mi anti 300m1 drained respectively and shown in Table 1.
Table 1 Treatment Dose (ppm) Seconds for Seconds for Seconds for 1 OOmI 200m1 300m1 Retention 300 5 ' 2g 7g Aid Bentonite 3000 Retention 500 5 23 Aid Bentonite 3000 Retention 500 3 15 42 Aid Cooked Starch30000 Retention 500 3 15 37 Aid Cooked Starch40000 Retention 500 2.5 12 31 Aid Cooked Starch60000 As can be seen the tests using cooked starch in place of bentonite gave faster free drainage.
Examale 4 Britt dynamic retention tests were carried out on a packaging grade paper furnish derived from waste using a copolymer of acrylamide with dimethyiaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12dllg as the retention aid and either bentonite or cooked starch as the reflocculating composition. The solids content in the water drained and the retention were measured for each test and shown in Table 2.
The following examples illustrate the invention.
WO 00/12819 PCTlEP99/05999 Example 1 110 grams per square metre hand sheet was prepared by flocculating cellulosic thin stock with higher molecular weight water soluble cationic polymer derived from acrylamide and cationic monomer in conventional manner followed by shearing followed by the addition of an aqueous reflocculating composition.
The burst strength (in KPA) depended on the reflocculating composition.
In one series of experiments, the reflocculating composition consisted of an aqueous dispersion of bentonite alone or with anionic potato starch. The burst strength when the bentonite was used alone was 299KPA. The burst strength when the anionic potato starch was cooked in the bentonite dispersion was 352 and the burst strength when the anionic starch was cooked and added after the shearing but before the bentonite was 322.
Example 2 Example 1 was repeated and varying the reflocculating composition. When bentonite was added alone the burst strength was 169. The burst strength when precooked anionic starch was included in the bentonite dispersion was 281. The burst strength when the anionic starch was cooked in the bentonite was 350. The burst strength when the anionic starch was precooked and added after the shearing, but in the absence of any bentonite during the process, was 308.
When amphoteric starch was included and cooked in the bentonite, the burst strength was 271. When amphoteric starch was cooked and added after the shearing stage but without the addition of bentonite then or subsequently good retention was obtained and the burst strength was 379. In this series of experiments the amount of starch was 7% based on fibre.
Example 3 Free drainage test was carried out on a packaging grade paper furnish derived from waste using a copolymer of acryiamide with dimethylaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12d1/g as the retention aid and either bentonite or cooked starch as the reflocculating composition.
For each dose the free drainage was measured in secands for 100m1. 200mi anti 300m1 drained respectively and shown in Table 1.
Table 1 Treatment Dose (ppm) Seconds for Seconds for Seconds for 1 OOmI 200m1 300m1 Retention 300 5 ' 2g 7g Aid Bentonite 3000 Retention 500 5 23 Aid Bentonite 3000 Retention 500 3 15 42 Aid Cooked Starch30000 Retention 500 3 15 37 Aid Cooked Starch40000 Retention 500 2.5 12 31 Aid Cooked Starch60000 As can be seen the tests using cooked starch in place of bentonite gave faster free drainage.
Examale 4 Britt dynamic retention tests were carried out on a packaging grade paper furnish derived from waste using a copolymer of acrylamide with dimethyiaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12dllg as the retention aid and either bentonite or cooked starch as the reflocculating composition. The solids content in the water drained and the retention were measured for each test and shown in Table 2.
Table 2 Treatment Dose (ppm) Back water solids Retention %
Retention Aid 500 0.240 79.6 Bentonite 3~0 Retention Aid 500 0.198 83.8 Cooked Starch 40000 As can be seen from the results the test with cooked starch shows improved retention.
Example 5 Example 3 was repeated except using a newsprint stock derived from 70% deinked waste and 30% mechanical pulp. The results are shown in table 3.
Table 3 Treatment Dose (ppm) Seconds for Seconds for Seconds for 1 OOmI 200m1 300m1 Retention 1000 11 45 -Aid Bentonite 3000 Retention 1000 5 23 60 Aid Cooked Starch40000 The test using cooked starch showed improved drainage times.
Example 6 Example 4 was repeated except using a newsprint stock derived from 70% deinked waste and 30% mechanical pulp. The results are shown in table 4 WO 00/12$19 PCT/EP99/05999 Table 4 Treatment Dosee (ppm)Back water solidsRetention ~
%
Retention Aid 1000 0.38 68.6 Bentonite 3000 Retention Aid 1000 0.27 77.7 Cooked Starch 40000 Higher retention was achieved using cooked starch in place of bentonite.
Example 7 The process of Example 1 was repeated using a 0.7% brown millstock and using grams per tonne of a copolymer of acrylamide with dimethylaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12dllg as the retention aid. Five series of experiments were conducted using as the sole reflocculating composition an anionic cooked starch, three types of amphoteric cooked starch and an unmod~ed cooked potato starch at various doses. The burst strength of the paper sheets formed were measured and the results are shown in Table 5.
Table 5 Cooked Starch RetlocculatingCorrected Composition Burst Strengths (Kpa) for various starch dosages (Kg/tonne) anionic Aniofax AP25 228.6 256.8 260.41 280.6 279.5 amphoteric CATO 245 259.2 284.1 273.9 308.4 316.0 amphoteric CATO 247 255.0 253.9 263.0 289.3 320.5 arnphoteric CATO 255 257.8 266.7 294.7 314.4 346.7 Unmodified Potato Starch 239.7 243.8 260.6 269.1 271.2 ~ i As a comparison the process was repeated using bentonite in place of cooked starch.
The burst sttrengths are shown in Table 6.
Retention Aid 500 0.240 79.6 Bentonite 3~0 Retention Aid 500 0.198 83.8 Cooked Starch 40000 As can be seen from the results the test with cooked starch shows improved retention.
Example 5 Example 3 was repeated except using a newsprint stock derived from 70% deinked waste and 30% mechanical pulp. The results are shown in table 3.
Table 3 Treatment Dose (ppm) Seconds for Seconds for Seconds for 1 OOmI 200m1 300m1 Retention 1000 11 45 -Aid Bentonite 3000 Retention 1000 5 23 60 Aid Cooked Starch40000 The test using cooked starch showed improved drainage times.
Example 6 Example 4 was repeated except using a newsprint stock derived from 70% deinked waste and 30% mechanical pulp. The results are shown in table 4 WO 00/12$19 PCT/EP99/05999 Table 4 Treatment Dosee (ppm)Back water solidsRetention ~
%
Retention Aid 1000 0.38 68.6 Bentonite 3000 Retention Aid 1000 0.27 77.7 Cooked Starch 40000 Higher retention was achieved using cooked starch in place of bentonite.
Example 7 The process of Example 1 was repeated using a 0.7% brown millstock and using grams per tonne of a copolymer of acrylamide with dimethylaminoethyl acrylate, methyl chloride quaternary ammonium salt of intrinsic viscosity in excess of 12dllg as the retention aid. Five series of experiments were conducted using as the sole reflocculating composition an anionic cooked starch, three types of amphoteric cooked starch and an unmod~ed cooked potato starch at various doses. The burst strength of the paper sheets formed were measured and the results are shown in Table 5.
Table 5 Cooked Starch RetlocculatingCorrected Composition Burst Strengths (Kpa) for various starch dosages (Kg/tonne) anionic Aniofax AP25 228.6 256.8 260.41 280.6 279.5 amphoteric CATO 245 259.2 284.1 273.9 308.4 316.0 amphoteric CATO 247 255.0 253.9 263.0 289.3 320.5 arnphoteric CATO 255 257.8 266.7 294.7 314.4 346.7 Unmodified Potato Starch 239.7 243.8 260.6 269.1 271.2 ~ i As a comparison the process was repeated using bentonite in place of cooked starch.
The burst sttrengths are shown in Table 6.
Table 6 Corrected Burst Strengths (Kpa) for various starch dosages (Kg/tonne) 0.5 1 2 3 4 bentonite 207 210 208 205 200 As can be seen the burst strength of the paper was greatly improved when using cooked starch as the refloccuiating composition.
Claims (9)
1. A process for making paper on a paper-making machine comprising providing a cellulosic thin stock suspension, flocculating the suspension by adding an aqueous solution of a polymeric retention aid selected from natural and synthetic polymer and thereby forming a flocculated suspension, shearing the flocculated suspension, reflocculating the sheared suspension by adding an aqueous reflocculating suspension, draining the reflocculated suspension through a wire to form a sheet, and drying the sheet, characterised in that substantially fully cooked starch is added to the suspension after the shearing and before the draining.
2. A process according to claim 1 in which the substantially fully cooked starch is added in the aqueous reflocculating composition.
3. A process according to either preceding claim in which the aqueous reflocculating composition comprises an aqueous dispersion of anionic microparticulate material.
4. A process according to claim 3 in which the aqueous reflocculating composition comprises an aqueous dispersion of a swelling clay, colloidal silica, polysilic acid or polysilicate microgel or aluminium modified silicates.
5. A process according to claim 3 or claim 4 comprising the step of making the reflocculated composition by a process comprising mixing substantially uncooked starch with an aqueous dispersion of the microparticulate material and cooking the starch in that dispersion.
6. A process according to claim 2 in which the starch is amphoteric.
7. A process according to claim 6 in which the aqueous reflocculating composition is substantially free of anionic microparticulate material or synthetic polymeric retention aid.
8. A process according to any one of claims 1 to 7 in which the retention aid is selected from cationic starch and synthetic polymer.
9. A process according to any one of claims 1 to 8 in which the retention aid is a synthetic cationic polymer of intrinsic viscosity of at least 4dl/g.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9818917.8 | 1998-08-28 | ||
| GBGB9818917.8A GB9818917D0 (en) | 1998-08-28 | 1998-08-28 | Manufacture of paper |
| PCT/EP1999/005999 WO2000012819A1 (en) | 1998-08-28 | 1999-08-16 | Manufacture of paper |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2340641A1 true CA2340641A1 (en) | 2000-03-09 |
Family
ID=10838076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002340641A Abandoned CA2340641A1 (en) | 1998-08-28 | 1999-08-16 | Manufacture of paper |
Country Status (15)
| Country | Link |
|---|---|
| EP (1) | EP1109972A1 (en) |
| JP (1) | JP2002525448A (en) |
| KR (1) | KR20010072977A (en) |
| CN (1) | CN1314962A (en) |
| AU (1) | AU5735799A (en) |
| BR (1) | BR9913146A (en) |
| CA (1) | CA2340641A1 (en) |
| GB (1) | GB9818917D0 (en) |
| HU (1) | HUP0103273A2 (en) |
| ID (1) | ID28511A (en) |
| NO (1) | NO20010985L (en) |
| PL (1) | PL346277A1 (en) |
| SK (1) | SK2722001A3 (en) |
| TW (1) | TW499527B (en) |
| WO (1) | WO2000012819A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2635661C (en) * | 2005-12-30 | 2015-01-13 | Akzo Nobel N.V. | A process for the production of paper |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5482595A (en) * | 1994-03-22 | 1996-01-09 | Betz Paperchem, Inc. | Method for improving retention and drainage characteristics in alkaline papermaking |
| GB9410965D0 (en) * | 1994-06-01 | 1994-07-20 | Allied Colloids Ltd | Manufacture of paper |
| CA2276424C (en) * | 1996-12-31 | 2006-03-14 | Ciba Specialty Chemicals Water Treatments Limited | Processes of making paper and materials for use in this |
-
1998
- 1998-08-16 ID IDW20010408A patent/ID28511A/en unknown
- 1998-08-28 GB GBGB9818917.8A patent/GB9818917D0/en not_active Ceased
-
1999
- 1999-08-09 TW TW088113687A patent/TW499527B/en active
- 1999-08-16 JP JP2000571073A patent/JP2002525448A/en active Pending
- 1999-08-16 HU HU0103273A patent/HUP0103273A2/en unknown
- 1999-08-16 CN CN99810194A patent/CN1314962A/en active Pending
- 1999-08-16 SK SK272-2001A patent/SK2722001A3/en unknown
- 1999-08-16 PL PL99346277A patent/PL346277A1/en unknown
- 1999-08-16 KR KR1020017002424A patent/KR20010072977A/en not_active Application Discontinuation
- 1999-08-16 BR BR9913146-3A patent/BR9913146A/en not_active Application Discontinuation
- 1999-08-16 CA CA002340641A patent/CA2340641A1/en not_active Abandoned
- 1999-08-16 WO PCT/EP1999/005999 patent/WO2000012819A1/en not_active Application Discontinuation
- 1999-08-16 AU AU57357/99A patent/AU5735799A/en not_active Abandoned
- 1999-08-16 EP EP99944410A patent/EP1109972A1/en not_active Withdrawn
-
2001
- 2001-02-27 NO NO20010985A patent/NO20010985L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| SK2722001A3 (en) | 2001-09-11 |
| TW499527B (en) | 2002-08-21 |
| BR9913146A (en) | 2001-05-08 |
| KR20010072977A (en) | 2001-07-31 |
| JP2002525448A (en) | 2002-08-13 |
| NO20010985L (en) | 2001-04-24 |
| ID28511A (en) | 2001-05-31 |
| NO20010985D0 (en) | 2001-02-27 |
| WO2000012819A8 (en) | 2001-03-29 |
| EP1109972A1 (en) | 2001-06-27 |
| GB9818917D0 (en) | 1998-10-21 |
| CN1314962A (en) | 2001-09-26 |
| WO2000012819A1 (en) | 2000-03-09 |
| PL346277A1 (en) | 2002-01-28 |
| HUP0103273A2 (en) | 2002-01-28 |
| AU5735799A (en) | 2000-03-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |