EP1967649A1 - Concentrated aqueous gypsum suspensions and their use in paper production - Google Patents
Concentrated aqueous gypsum suspensions and their use in paper production Download PDFInfo
- Publication number
- EP1967649A1 EP1967649A1 EP08100527A EP08100527A EP1967649A1 EP 1967649 A1 EP1967649 A1 EP 1967649A1 EP 08100527 A EP08100527 A EP 08100527A EP 08100527 A EP08100527 A EP 08100527A EP 1967649 A1 EP1967649 A1 EP 1967649A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- gypsum
- weight
- phosphonic acid
- methylene
- salt
- 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.)
- Withdrawn
Links
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
- D21H17/63—Inorganic compounds
- D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
-
- 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
- D21H17/03—Non-macromolecular organic compounds
- D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
- D21H17/10—Phosphorus-containing compounds
-
- 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
- D21H17/37—Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
-
- 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
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/38—Coatings with pigments characterised by the pigments
-
- 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
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Process for the preparation of paper characterised by the fact that an aqueous gypsum suspension having Brookfield viscosity at 25°C and 100 rpm comprised between 100 and 1,000 mPa·s and containing from 60 to 85% by weight of gypsum in the form of calcium sulphate dihydrate (Ca2SO4.2H2O) is added to the cellulose aqueous suspension used for the production of paper, the aqueous gypsum suspension containing from 0.1 to 2% by weight of an acrylic sulphonated polymer, or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate, and from 0.1 to 1.0% by weight of an organic polyphosphonate.
Description
- The present invention relates to stable, concentrated aqueous gypsum suspensions that are useful for the production of paper and cardboard and contain high amounts of gypsum.
- In the present description, with the term stable, concentrated aqueous gypsum suspensions we mean suspensions having a CaSO4*2H2O concentration comprised between 60% and 85% by weight.
- In the following description we will use the term "paper" to include cardboard too.
- As it is known, many solutions have been proposed to make it possible to prepare stable, concentrated calcium sulphate suspensions, mainly based on the use of specific complexing agents and dispersants.
- In particular, in our Italian patent Application
VA2006A000044 - These low viscous, highly stable and highly concentrated gypsum suspensions are mixable with suspensions based on other pigments and they do not form foams, which would render troublesome their use.
- While continuing our research on the compositions disclosed in the above said patent application, it was found that it is possible to use the suspensions described therein (modified in their particle size distribution) directly in the production of paper, to charge it with calcium sulphate as filler in the desired quantity.
- As it is known, the use of calcium sulphate as additive in paper production is always looked at suspiciously in paper mills, despite its low cost among additives, because of its tendency to form solid masses that could stop the paper production plant.
- In European patent
EP 0056200 B1 a method was described allowing the use of aqueous calcium sulphate suspensions, which are directly prepared in a reactor located next to the paper production plant and introduced in diluted form (generally with concentration below 20%) directly in the paper production plant. - This method has a drawback: it also needs the preparation, directly next to the paper production plant, of the aqueous suspension of calcium sulphate, because it is economically disadvantageous to transport the large amounts of water of such suspensions.
- The Applicant has now found that it is possible to use stable, concentrated aqueous suspensions of gypsum in the production of paper.
- It is therefore a fundamental object of the present invention a process for the production of paper containing from 5 to 35% by weight of calcium sulphate dihydrate, characterised by the fact that a stable aqueous gypsum suspension having Brookfield viscosity at 25°C and 100 rpm comprised between 100 and 1,000 mPa*s and containing from 60 to 85% by weight of gypsum in the form of calcium sulphate dihydrate (Ca2SO4.2H 2O) is added to the cellulose aqueous suspension used for the production of paper.
- In particular, said stable, aqueous gypsum suspension, which represents a further object of the present invention, contains from 0.1 to 2% by weight of an acrylic sulphonated polymer, or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate, and from 0.1 to 1 % by weight of an organic polyphosphonate, and comprises gypsum in dihydrate form having particle size between 35% and 60% below 2 micron.
- The use of an acrylic sulphonated polymer or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate, acting as dispersing agent, and of the organic polyphosphonate allows to obtain stable, concentrated gypsum suspensions having rheological characteristics and stability which render them suitable for use in the method according to the invention.
- The use of a polynaphthalene sulphonate is preferred, because, advantageously, it can also be used in acid environments, that are typical of the paper production with acidic sizing, that is at pH about 4.5.
- Preferably the Brookfield viscosity of the suspensions, at 25°C and 100 rpm, is comprised between 100 and 500 mPa*s.
- The acrylic sulphonated polymers useful for the preparation of the suspensions of the present invention are obtained by polymerisation of acrylic and/or methacrylic acid, in acidic or salt form, with a monomer containing a sulphonic functional group and have a molecular weight from 5,000 to 40,000 dalton (measured with an acrylic acid standard); they are well known polymers, available on the market, and sold by way of example in the form of aqueous slurries by Lamberti SpA; they can be used in this form for the preparation of the gypsum suspensions of the invention.
- Preferably the molar ratio between the total sum of acrylic and/or methacrylic acid and monomer containing a strongly acidic functional group is from 3 to 30, preferably from 3 to 10.
- More preferably, the sulphonated acrylic polymer is a copolymer of acrylic acid, methacrylic acid and 2-acrylamido-2-methyl-1-propanesulphonic acid, where the molar ratio between acrylic and methacrylic acid is from 2 to 8.
- The polynaphthalene sulphonates useful for the realisation of the present invention are condensation products of formaldehyde and sulphonated aromatics acting as dispersants, and are also normally available in the market; they are generally prepared by reacting an aromatic sulphonated compound (such as naphthalene sulphonic acids, naphthol sulphonic acids, alkylated naphthalene sulphonic acids, alkylated naphthol sulphonic acids, and also toluenesulphonic acid, benzenesulphonic acid, phenolsulphonic acid and similar compounds) with formaldehyde, to form a condensation product which is usually neutralised or alkalinised by adding a sodium hydroxide solution.
- Among the sulphonated formaldehyde-aromatic condensation products which are commercially available as dispersants and are useful for the realisation of the present invention we cite TAMOL NN 9104, sold by BASF.
- Among the acrylic carboxylated polymers useful for the realization of the present invention we cite the copolymers of acrylic, methacrylic, itaconic, fumaric, maleic acid, optionally copolymerized with acrylamide, having molecular weight from 1,000 to 10,000 dalton and obtained by using as initiators persulfate/metabisulfite or ipophosphite and as neutralising agents sodium or potassium hydroxides, or carbonates.
- In the present text, with the term "organic polyphosphonate" we mean organic phosphonates containing two or more phosphonic groups, in the form of acid or salt thereof.
- Polyphosphonates useful for the realisation of the present invention are: aminotri(methylene-phosphonic acid), aminotri(methylene-phosphonic acid)pentasodium salt, 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid tetrasodium salt, diethylenetriamine penta(methylene phosphonic acid)pentasodium salt, diethylenetriamine penta(methylene phosphonic acid)trisodium salt, hexamethylene diamine tetra(methylene phosphonic acid), hexamethylene diamine tetra(methylene phosphonic acid)potassium salt, and mixtures thereof.
- Other useful polyphosphonates are described in
EP 1713568 . - The aqueous gypsum suspensions of the present invention are repared by adding hemi-hydrate gypsum to an aqueous solution containing the dispersing agents and the organic polyphosphonate in a bead mill, gently grinding to homogenise the suspension.
- The dihydrate gypsum which is obtained in these conditions has a particle size from 35% to 60% by weight below 2 microns.
- The grinding avoids excessive sedimentation and compaction of the product, even in case no suspending agents are used.
- According to a particularly advantageous aspect of this invention, it is observed that the possible presence of sedimentation in the suspension can be eliminated by simple mechanical stirring, even after months from its preparation.
- The hemi-hydrate gypsum useful for the preparation of the aqueous suspensions of the present invention is commercially available and is normally obtained by calcinating dihydrate gypsum.
- EXAMPLE 1
- 3 gypsum suspensions are prepared with the following ingredients:
- • Hemi-hydrate calcium sulphate
- • Sequion 50 K33 (33% by weight hexamethylene diamine tetra(methylene phosphonic acid) potassium salt from Bozzetto SpA, Italy)
- • AA= 45% aqueous solution of sodium acrylate homopolymer
- • AA-MA-AMPS=30% aqueous slurry of acrylic acid, methacrylic acid and 2-acrylamido-2-methyl-1-propansulphonic acid sodium salt terpolymer (monomers molar ratio: 4: 1: 1)
- • Tamol NN 0104, polynaphthalene sulphonate from BASF (Germany)
- with the quantities reported in Table 1 and the following procedure:
- The bead mill is charged with 400.6 g of water, 6.9 g of Sequion 50 K33 and 8.2 g of Tamol NN 0104.
- Stirring is started and 584.3 g of calcium sulphate hemi-hydrate are added with 300ml of beads having diameter 1.5-2.0 mm.
- After 30 minutes stirring the product is discharged.
- The next samples were prepared using the same procedure and substituting Tamol NN 0104 with AA-MA-AMPS (Suspension 2) or with AA (Suspension 3).
-
Table 1 Calcium sulfate dihydrate suspensions Sample No. Susp. Conc. % Tamol NN 9104 % AA-MA-AMPS % AA % Brookfiel d Viscosity 100 rpm (mPa*s) Particle size % < 2 µm 1 70,0 1,2% / / 270 42,8 2 70,0 / 1,0 / 215 40,1 3 70,0 / / 1,0 310 43,5 - EXAMPLE 2
- Use of the calcium sulphate dihydrate suspensions as fillers in the production of paper sheets.
- Ingredients:
- Calcium sulphate dihydrate suspension prepared as Sample No 1 of Example 1
- Calcium sulphate dihydrate suspension prepared according to the method of patent
EP 0056200 B1 - Cellulose paste (3% in water)
- Colloidal silica (Nalco 8694, from Nalco, USA, 0.01 % solution)
- Retention agent (Nalco 74648, anionic polyacrylamide from Nalco, USA, 0.01 % solution)
- Two series of sheets are prepared having different fillers, the first with calcium sulphate dihydrate prepared as sample No. 1 of Example 1, the second with calcium sulphate dihydrate prepared according to the method of patent
EP 0056200 B1 . - To obtain 80 g/m2 sheets, 65 g of cellulose fibre paste are taken and 0.93 g of calcium sulphate dihydrate prepared as sample No. 1 of Example 1 are added into it (1st series), diluting with water saturated with calcium sulphate dihydrate to 500 g total weight.
- 7.8 g of colloidal silica Nalco 8694 (0.01 % solution) and 0.5 g of retention agent Nalco 74648 (0.01 % solution) are then added.
- The paste is then inserted in the sheet-maker machine and the sheet is prepared.
- The 2nd series is prepared in the same conditions.
- For each series, 6 sheets having grammage of 80 g/m2 were prepared.
- The sheets are conditioned for 24 hours in a room at 21°C and 50 % r.h.
- Example 2.1
- The sheets prepared as in Example 2 were characterised by taking the following measurements, and reporting the results in Table 2:
- Grammage - Tappi method T410
- Opacity - Tappi method T425
- Ash at 500 and 900°C - Tappi method T211
- Charge
- Tensile breaking - Tappi method T494
-
Table 2 1ST SERIES 2ND SERIES ASH % 500°C 22.61 20.77 900°C 20.56 18.15 CHARGE % 28.26 25.96 Opacity 93.83 93.64 Tensile breaking (m) 3465 3563 - The charge is calculated by multiplying the ash value at 500°C per 1.25 (conversion factor from CaSO4 to CaSO4*2H2O).
Claims (9)
- A process for the preparation of paper containing from 5 to 35% by weight of calcium sulphate dihydrate, characterised by the fact that an aqueous gypsum suspension having Brookfield viscosity at 25°C and 100 rpm comprised between 100 and 1,000 mPa*s and containing from 60 to 85% by weight of gypsum in the form of calcium sulphate dihydrate (Ca2SO4.2H2O) is added to the cellulose aqueous suspension used for the production of paper, the aqueous gypsum suspension containing from 0.1 to 2% by weight of an acrylic sulphonated polymer, or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate, and from 0.1 to 1.0% by weight of an organic polyphosphonate.
- The process as claimed in 1 further characterised by the fact that from 35% to 60% of the gypsum contained in the suspension has particle size below 2 micron.
- The process as claimed in 1 or 2 where the gypsum aqueous suspension contains from 0.1 to 2.0% by weight of a polynaphthalene sulphonate.
- The process as claimed in 3 where the gypsum aqueous suspension has Brookfield viscosity, at 25°C and 100 rpm, between 100 and 500 mPa*s.
- The process as claimed in 4 where the polyphosphonate is selected among: aminotri(methylene-phosphonic acid), aminotri(methylene-phosphonic acid)pentasodium salt, 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid tetrasodium salt, diethylenetriamine penta(methylene phosphonic acid)pentasodium salt, diethylenetriamine penta(methylene phosphonic acid)trisodium salt, hexamethylene diamine tetra(methylene phosphonic acid), hexamethylene diamine tetra(methylene phosphonic acid)potassium salt, and mixtures thereof.
- A gypsum aqueous suspension having Brookfield viscosity at 25°C and 100 rpm comprised between 100 and 1,000 mPa*s containing: a. from 60 to 85% by weight of calcium sulphate dihydrate (Ca2SO4.2H2O) having particle size between 35 and 60% by weight below 2 micron; b. from 0.1 to 2.0% by weight of an acrylic sulphonated polymer, or of an acrylic carboxylated polymer or of a polynaphthalene sulphonate; c. from 0.1 to 1.0% by weight of an organic polyphosphonate.
- The gypsum aqueous suspension according to claim 6 having Brookfield viscosity, at 25°C and 100 rpm, between 100 and 500 mPa*s.
- The gypsum aqueous suspension according to claim 6 or 7 containing from 0.1 to 2.0% by weight of a polynaphthalene sulphonate.
- The gypsum aqueous suspension of claim 8 where the polyphosphonate is selected among: aminotri(methylene-phosphonic acid), aminotri(methylene-phosphonic acid)pentasodium salt, 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid tetrasodium salt, diethylenetriamine penta(methylene phosphonic acid)pentasodium salt, diethylenetriamine penta(methylene phosphonic acid)trisodium salt, hexamethylene diamine tetra(methylene phosphonic acid), hexamethylene diamine tetra(methylene phosphonic acid)potassium salt, and mixtures thereof.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITVA20070018 ITVA20070018A1 (en) | 2007-02-16 | 2007-02-16 | WATER SUSPENSIONS CONCENTRATED OF PLASTER FOR PAPER PREPARATION |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1967649A1 true EP1967649A1 (en) | 2008-09-10 |
Family
ID=39638678
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP08100527A Withdrawn EP1967649A1 (en) | 2007-02-16 | 2008-01-16 | Concentrated aqueous gypsum suspensions and their use in paper production |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1967649A1 (en) |
IT (1) | ITVA20070018A1 (en) |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3645677A (en) * | 1968-09-24 | 1972-02-29 | Taki Fertilizer Mfg Co Ltd | Production of gypsum |
DE3203067A1 (en) * | 1981-02-04 | 1982-08-26 | Kemira Oy, 00100 Helsinki | Gypsum slurry |
GB2173781A (en) * | 1985-04-11 | 1986-10-22 | Berol Kemi Ab | Water slurry of gypsum or chalk |
EP0056200B1 (en) | 1981-01-02 | 1987-09-23 | S.A. Josep Maria Gussinyer | Process for preparing and using a crystalline product |
DE4027237A1 (en) * | 1990-08-29 | 1992-03-05 | Gypsum Research | High solids aq. dispersions of flue gas gypsum - contg. a surface active sulphonate and complexing agent |
WO1992008755A1 (en) * | 1990-11-07 | 1992-05-29 | Ecc America Inc. | Aggregated composite mineral pigments |
US5236989A (en) * | 1989-12-29 | 1993-08-17 | Ecc International Inc. | Aggregated composite mineral pigments |
US20040187741A1 (en) * | 2003-03-27 | 2004-09-30 | United States Gypsum Company | Ready-mixed setting-type composition and related kit |
EP1713568A1 (en) | 2004-02-02 | 2006-10-25 | Giovanni Bozzetto S.p.a. | Use of polyaminothylenephosphonates as dispersing agents |
-
2007
- 2007-02-16 IT ITVA20070018 patent/ITVA20070018A1/en unknown
-
2008
- 2008-01-16 EP EP08100527A patent/EP1967649A1/en not_active Withdrawn
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3645677A (en) * | 1968-09-24 | 1972-02-29 | Taki Fertilizer Mfg Co Ltd | Production of gypsum |
EP0056200B1 (en) | 1981-01-02 | 1987-09-23 | S.A. Josep Maria Gussinyer | Process for preparing and using a crystalline product |
DE3203067A1 (en) * | 1981-02-04 | 1982-08-26 | Kemira Oy, 00100 Helsinki | Gypsum slurry |
GB2173781A (en) * | 1985-04-11 | 1986-10-22 | Berol Kemi Ab | Water slurry of gypsum or chalk |
US5236989A (en) * | 1989-12-29 | 1993-08-17 | Ecc International Inc. | Aggregated composite mineral pigments |
DE4027237A1 (en) * | 1990-08-29 | 1992-03-05 | Gypsum Research | High solids aq. dispersions of flue gas gypsum - contg. a surface active sulphonate and complexing agent |
WO1992008755A1 (en) * | 1990-11-07 | 1992-05-29 | Ecc America Inc. | Aggregated composite mineral pigments |
US20040187741A1 (en) * | 2003-03-27 | 2004-09-30 | United States Gypsum Company | Ready-mixed setting-type composition and related kit |
EP1713568A1 (en) | 2004-02-02 | 2006-10-25 | Giovanni Bozzetto S.p.a. | Use of polyaminothylenephosphonates as dispersing agents |
Also Published As
Publication number | Publication date |
---|---|
ITVA20070018A1 (en) | 2008-08-17 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1966258B1 (en) | Copolymers based on unsaturated monocarboxylic or dicarboxylic acid derivatives and oxyalkylene glycol alkenyl ethers, process for preparing them and their use | |
US8476391B2 (en) | Anionic water-in-water polymer dispersion, method for the production thereof and its use | |
JP4260930B2 (en) | Aqueous suspension of inorganic substances and use thereof | |
CN101501147B (en) | Dispersing and/ or grinding aid agent for dispersion and aqueous suspension of mineral materials, dispersion and suspension obtained and use thereof | |
EP2651991B1 (en) | Stable polyacrylic acids, their manufacture and their use | |
CN101608047B (en) | Water-soluble polymer dispersion liquid, paper strengthening agent, drainability improving agent and retention agent for making paper | |
KR20030062421A (en) | Method for the production of water-in-water polymer dispersions | |
AU5505900A (en) | Cement compositions comprising redispersible polymer powders | |
US20100184897A1 (en) | Procedure for manufacturing an aqueous formulation based on a solution of acrylic comb polymer and acrylic thickening emulsion, the formulation obtained and its use in coating paper | |
KR101871016B1 (en) | Low-molecular-weight polyacrylic acids containing phosphorus and use thereof as dispersants | |
CN1385392A (en) | Application of powder composition used as rheological additives | |
CN109704619B (en) | Sulfamate high-efficiency water reducing agent and preparation process thereof | |
BR112019008465B1 (en) | ACRYLIC ACID POLYMER, PROCESS FOR PREPARING AQUEOUS SOLUTIONS OF ACRYLIC ACID POLYMERS, AND USE OF ACRYLIC ACID POLYMERS | |
KR101912979B1 (en) | Aqueous polymer composition for paper coating | |
JP2011168948A (en) | Water-soluble polymer dispersion, paper strengthening agent, freeness enhancement agent for papermaking, and yield enhancement agent for papermaking | |
WO2017134128A1 (en) | Method for producing acrylic acid polymers | |
FR3013350A1 (en) | FLUIDITE RETENTION AGENT FOR HYDRAULIC COMPOSITION COMPATIBLE WITH POLYMER-TYPE WATER-REDUCING AGENT | |
EP3097061B1 (en) | Calcium sulphate composition including an additive | |
EP1967649A1 (en) | Concentrated aqueous gypsum suspensions and their use in paper production | |
WO2012104304A1 (en) | Low molecular mass, phosphorus-containing polyacrylic acids and use thereof as dispersants | |
WO2010080453A2 (en) | Methods for stabilizing hydrous kaolin | |
JPH0197296A (en) | Cation fixing pigment dispersion and coating agent | |
EP2971349B1 (en) | Method of using aldehyde-functionalized polymers to increase papermachine performance and enhance sizing | |
AU2005303977B2 (en) | Aqueous paper coating slip containing pigment-polymer hybrids | |
JP4873691B2 (en) | Calcium carbonate dispersion and preparation method thereof |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA MK RS |
|
AKX | Designation fees paid | ||
REG | Reference to a national code |
Ref country code: DE Ref legal event code: 8566 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20090311 |