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
  • 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
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/58—Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof
• • 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
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/60—Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters

Definitions

• the invention relates to paper coating slips containing at least 5 to 25 parts by weight of a copolymer A per 100 parts by weight of a finely divided pigment with a glass transition temperature of -40 to + 50 ° C. in the form of aqueous dispersions and 0.5 to 10 parts by weight contain a copolymer B of a high molecular weight, carboxyl group-containing copolymer.
• paper coating slips which consist essentially of a pigment dispersed in water, e.g. Kaolin, calcium carbonate or titanium dioxide, and a binder.
• a pigment dispersed in water e.g. Kaolin, calcium carbonate or titanium dioxide
• binders While previously only high-molecular natural products such as starch or casein were used as binders, attempts are increasingly being made to replace all or part of the natural products with synthetic, high-molecular polymers in the form of aqueous dispersions. Binders based on natural products have the disadvantages that they are not always of the same quality, are sensitive to the attack by microorganisms, have to be broken down by complex processes and produce brittle lines. Binders based on synthetic high polymers do not have all of the disadvantages of the natural binders mentioned, but are still in need of improvement.
• the invention has for its object to provide a paper coating slip which has a high water retention, and whose binder brings about the effect of any optical brighteners present.
• binder combinations mentioned give the paper coating slips according to the invention a high water retention, so that they can be easily processed on conventional coating systems.
• copolymers B activate the optical brighteners.
• Suitable copolymers A of the binder mixture are all commercially available synthetic binders which are present as an aqueous dispersion.
• the polymers have a glass transition temperature of -40 to + 50 ° C.
• Typical monomers involved in the construction of these polymers are, for example, esters of acrylic acid and methacrylic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, C3- to C s -ethylenically unsaturated mono- and dicarboxylic acids, half-esters of ethylenically unsaturated C 3 -C 5 --Dicarboxylic acids, vinyl chloride, vinylidene chloride, mono- or polyethylenically unsaturated hydrocarbons, such as ethylene, propylene, butylene, 4-methylpentene-1, styrene, butadiene, isoprene and chloroprene, vinyl esters, vinyl sulfonic acid, and esters of
• Suitable copolymers A are known, for example, from DE-AS 1 100 450.
• such copolymers can also contain styrene and / or butadiene and / or acrylonitrile and ethylenically unsaturated acids.
• acids instead of the acids, other polymerizable hydrophilic compounds can also be copolymerized into the copolymers.
• monomers containing hydroxyl groups such as hydroxypropyl acrylate and methacrylate.
• the acrylic esters used in the polymerization can be derived, for example, from monohydric alcohols having 1 to 12 carbon atoms.
• the acrylic ester content in these copolymers can vary within wide limits, for example between 10 and 99%, or homopolymers of acrylic acid esters can be used.
• the content of ethylenically unsaturated acids in these copolymers is generally up to 10% by weight.
• Acrylic acid is the primary ethylenically unsaturated acid re, methacrylic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid and itaconic acid.
• the polymethacrylates have a structure similar to that of the polyacrylates, but contain a methacrylic acid ester instead of an acrylic acid ester. However, it is also possible to copolymerize acrylic acid esters and methacrylic acid esters together with other ethylenically unsaturated compounds and to use them as component A of the binder combination. Ethylene or propylene, for example, are also suitable as comonomers.
• copolymer A also suitable as copolymer A are copolymers of butadiene and styrene. These copolymers contain 20 to 60% by weight of butadiene and 40 to 80% by weight of styrene and / or acrylonitrile. They can contain further comonomers, for example esters of ethylenically unsaturated carboxylic acids having 3 to 5 carbon atoms and optionally up to 10% by weight of other ethylenically unsaturated copolymerizable compounds, such as acrylic acid, methacrylic acid, maleic acid, crotonic acid and fumaric acid. Polymers of this type, and also polyacrylates, are known for example from DE-PS 1 546 316.
• Suitable styrene-butadiene copolymers which contain an ethylenically unsaturated carboxylic acid or a half ester of an ethylenically unsaturated dicarboxylic acid in copolymerized form and are used as copolymer A are known from DE-AS 1 221 748.
• copolymer A in the paper coating slip according to the invention are polymers which are derived from vinyl esters, for example of the vinyl acetate or vinyl propionate type, and polymerizable hydrocarbons, for example ethylene or propylene, for example copolymers of vinyl esters with acrylic esters and / or methacrylic esters and / or acrylonitrile and other polymeric Containable hydrophilic compounds, for example containing copolymerized ethylenically unsaturated compounds, such as acrylamide, N-methylolacrylamide, N-methylolmethacrylamide, vinyl chloride or vinylidene chloride.
• Suitable vinyl ester copolymers are known for example from DE-PS 1 264 945. Homopolymers of vinyl esters can also be used.
• comonomers of group b acrylic acid and / or methacrylic acid in particular are used. These comonomers are preferably present in the copolymers B in an amount of 15 to 40% by weight.
• maleic acid semiesters which are also to be used as comonomer of group b), those which are derived from monohydric alcohols having 1 to 4 carbon atoms are particularly suitable.
• Comonomers of group c) which are 5 to 50, preferably 20 to 40% by weight of the structure of the copolymers B are acrylonitrile, methacrylonitrile, esters of acrylic acid or methacrylic acid with monohydric C 1 to C 4 alcohols and Vinyl esters of saturated C 2 - to C 4 -carboxylic acids into consideration.
• carboxylic acid esters especially suitable are methyl acrylate, ethyl acrylate, methyl methacrylate, vinyl acetate and vinyl propionate.
• Preferably used as comonomer of group c) is acrylonitrile, methyl acrylate and / or ethyl acrylate.
• the polymerization of the monomers is started using the usual polymerization initiators.
• peroxides such as peroxydisulfates, hydrogen peroxide, hydroperoxides and azo compounds, and also redox catalysts can be used.
• the usual polymerization regulators can be used, e.g. Mercaptans such as t-dodecyl mercaptan, thioglycolic acid etc. or hydroxylammonium salts.
• the L which is insoluble or only very poorly soluble in water is used to emulsify Comonomers commercially available emulsifiers.
• the copolymerization can, for example, be carried out batchwise in a stirred kettle by first introducing part of the monomer mixture and then adding the rest in accordance with the course of the polymerization. However, the reaction can also be carried out continuously in a cascade.
• the paper coating slips according to the invention contain 5 to 25 parts by weight, based in each case on 100 parts by weight of pigment, of polymer A and 0.1 to 10 parts by weight of the solid copolymer B.
• These polymer combinations are excellent binders for paper coating slips. They are preferably used for the production of such paper coating slips which contain 0.1 to 2% by weight of an optical brightener.
• Optical brighteners are described, for example, in summary by H. Gold in Venkataraman, The Chemistry of Synthetic Dyes, Academic Press, New York and London 1971, Volume 5, Chapter 8, pages 536 to 679. Optical brighteners are commercially available, so that this can be found superfluous explanations are unnecessary. For further characterization of this class of substances, however, reference is made to DE-OS 2 628 878 and DE-AS 1 795 047. This describes optical brighteners based on stilbene derivatives, which are preferably used.
• copolymers A and B are mixed with fillers or pigments in a manner known per se. Suitable substances of this type are above all clay minerals, calcium carbonates, calcium aluminum pigments or titanium dioxide. Possibly. You can also add other auxiliaries to the paper coating slips, for example alkalis, such as sodium hydroxide, potassium hydroxide or ammonia, or else white pigments based on water-insoluble urea-formaldehyde condensation products or other known paper-1 auxiliaries, such as urea, melamine, melamine-formaldehyde resins or urea-formaldehyde resins.
• alkalis such as sodium hydroxide, potassium hydroxide or ammonia
• white pigments based on water-insoluble urea-formaldehyde condensation products or other known paper-1 auxiliaries, such as urea, melamine, melamine-formaldehyde resins or urea-formaldehyde resins.
• a dispersant for example low molecular weight polymers of acrylic acid, especially the ammonium or sodium salts of polyacrylic acid with a K value of 10 to 35 are used.
• the order in which the individual components of the paper coating slip are mixed is not critical. However, it proves advantageous to add the copolymer B at the end of the coating color preparation.
• the copolymers B can be regarded as cobinders because they themselves have a pigment binding capacity.
• the copolymers B also act in partially neutralized or fully neutralized form as thickeners, i.e. they increase the viscosity of the aqueous paper coating slip. They also increase the water retention of the coating color, do not decrease the effect of the optical brighteners, on the contrary, they activate them. It is already possible to achieve the effects described with relatively small amounts of polymer B, e.g. 0.1 to 10% by weight of the solid product, preferably 0.2 to 3% by weight of water-soluble copolymer B, based on the pigment weight, are sufficient to achieve the above-mentioned improvements in the quality of coating color and paper.
• the invention is illustrated by the following examples.
• the parts given in the examples are parts by weight, the percentages relate to the weight of the substances, unless stated otherwise.
• the K values of the copolymers B are between approximately 60 and 140, preferably between 80 and 120.
• a 2-1 flask is used as the polymerization apparatus, which is equipped with a stirrer, reflux condenser, thermometer and 2 feed vessels.
• the polymerization is carried out in the absence of oxygen in a nitrogen atmosphere.
• the feed vessel I contains a mixture which was prepared as follows: 7 g of a 28% strength solution of a reaction product were added to 548 g of water, which by sulfation of 3 mol of ethylene oxide with 1 mol of a C 12 / C 14 -saturated aliphatic alcohol and neutralization of the reaction product was obtained.
• Feed II consists of 100 g of water and 4 g of sodium peroxydisulfate. 10% of feed II and 274 g of water are placed in the polymerization apparatus and heated to a temperature of 90 ° C. with stirring. As soon as the temperature of the initial charge is 90 ° C., the feeds I and II are allowed to flow in with thorough mixing within 2 hours and the polymerization is carried out at 90 ° C. Then another 4 g of sodium peroxydisulfate dissolved in 100 g of water are added to the polymerization batch within 50 minutes. After polymerization for an hour, the reaction mixture is cooled and then filtered. An approximately 28% aqueous solution of the copolymer B1 is obtained. L
• Example 1 The polymerization apparatus described in Example 1 is used, 335 g of water are placed in it and the mixture is heated to a temperature of 85 ° C.
• feed I a mixture of 670 g of water and 18 g of a 28% solution of the sodium salt of the sulfuric acid half-ester of 3-fold ethoxylated C 12 / C 14 alcohol mixtures, 75 g acrylic acid, which are neutralized with 42 g 50% sodium hydroxide solution, 200 g methyl acrylate, 225 g hydroxypropyl acrylate (mixture of 1-hydroxy-2-propyl and 2-hydroxy-1- propyl acrylate in a weight ratio of approximately 33:67) and 0.75 g of dodecyl mercaptan.
• An aqueous solution of 5 g of sodium peroxydisulfate in 200 g of water is used as feed II. Inlets I and II are added within 2.5 hours to the template heated to 85 ° C. and polymerized at the temperature mentioned.
• the post-polymerization is complete after 2 hours at a temperature of 85 0 C.
• the reaction mixture is then cooled and filtered.
• the copolymer obtained is B 2 with a K value of 89 in the form of an approximately 29% white emulsion.
• a paper coating slip which is suitable for the production of paper and for offset printing
• 80 parts of spreading clay and 20 parts of calcium carbonate pigment are dispersed in a 66% strength aqueous slurry using 0.2 parts with the aid of a powerful dispersing unit Sodium hydroxide solution and 0.3 part of a commercially available dispersant based on low molecular weight polyacrylic acid.
• 12 parts (based on the solids content) of an aqueous dispersion of a copolymer A composed of 50% n-butyl acrylate and 50% styrene are added to the pigment slurry.
• the copolymer B1 2 parts (based on J the solids content) of the copolymer B1, 1 part of a commercial optical brightener based on stilbene derivatives (Blancoohor PSG) and adjusts the solids content of the coating color to about 58% by adding water.
• the pH of the paper coating slip is adjusted to 8.5 with sodium hydroxide solution.
• the paper coating color can be processed, for example on a doctor coating machine. The properties of the coating color and the paper coated with it are given in the table.
• a coating color for the production of coated cardboard is obtained as described in Example 1 by using the pigment slurry described there with 15 parts of a commercial butadiene-styrene copolymer (48% butadiene and 43% styrene) containing 4% carboxyl groups (based on Solids content of the dispersion, mixed as copolymer A and water was added until the solids content of the mixture was 43%. Then, based on the solids content, 0.7 part of the copolymer B 2 and part of a commercial optical brightener based on stilbene derivatives (Blancophor PSG) are added. Then adjust the pH to 8.5 and homogenize the mixture for 15 minutes.
• a coating color is obtained which can be processed perfectly on an air brush coating system or a roller coating system. The properties of the coating color and the cardboard coated with it are given in the table.
• a coating color for the production of art paper 80 parts of coating clay and 20 parts of satin white are dispersed with 1.2 parts of a commercially available dispersant based on low molecular weight poly acrylic acid and 0.2 part of sodium hydroxide solution, so that an approximately 54% aqueous slurry is obtained. 16 parts of a copolymer A composed of 50% n-butyl acrylate and 50% vinyl acetate are mixed into this pigment slurry. Then 2.5 parts, based on the solids content, of copolymer B2 and 1 part of a commercial optical brightener based on stilbene derivatives (Blancophor PSG) are added with vigorous stirring and the solids content of the coating color is adjusted to 50% by adding water. The pH of the paper coating slip is adjusted to 11.3 and the paper coating slip is then mixed for a further 15 minutes. It can then be processed perfectly on a doctor coating system. The results are summarized in the table.
• the table also shows properties of coating colors and coated papers which were obtained in accordance with the comparative examples.
• a synthetic or natural cobinder instead of the copolymer B, was used, which corresponds to the prior art.
• the paper coating slips were otherwise prepared as described in Examples 1 to 3.
• Copolymer A according to Example 1 and instead of the copolymer B1 casein.
• Copolymer A according to Example 2 and a commercial starch instead of the copolymer B2.
• Copolymer A according to Example 3 and instead of the copolymer B2, a copolymer of 12% vinyl acetate, 30% methyl acrylate and 12% acrylic acid.
• Water retention was expressed in seconds. It is the time in which the aqueous phase of the coating color stained with an acidic red dye is penetrated so far through a blue-band filter that it reduces its reflectance, measured with a reflectance photometer (filter 4), to 40% of the original value.
• the degree of whiteness was given as reflectance, measured with UV-rich xenon light without a filter.
• the increase in whiteness relates to the corresponding value obtained with a UV filter.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Paints Or Removers (AREA)
• Glass Compositions (AREA)
• Analysing Materials By The Use Of Radiation (AREA)
• Tires In General (AREA)
• Lubricants (AREA)
• Polishing Bodies And Polishing Tools (AREA)

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• 1979
  • 1979-02-15 DE DE19792905765 patent/DE2905765A1/de not_active Withdrawn
• 1980
  • 1980-01-29 CA CA000344601A patent/CA1143883A/fr not_active Expired
  • 1980-02-04 FI FI800325A patent/FI64209C/fi not_active IP Right Cessation
  • 1980-02-07 EP EP80100620A patent/EP0014904B1/fr not_active Expired
  • 1980-02-07 DE DE8080100620T patent/DE3060063D1/de not_active Expired
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  • 1980-02-14 NO NO800413A patent/NO156872C/no unknown
  • 1980-02-14 ES ES488597A patent/ES488597A1/es not_active Expired
  • 1980-02-14 JP JP1611280A patent/JPS55112396A/ja active Granted
• 1981
  • 1981-08-31 US US06/298,162 patent/US4384069A/en not_active Expired - Lifetime

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