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
  • 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
  • D21H23/00—Processes or apparatus for adding material to the pulp or to the paper
  • D21H23/76—Processes or apparatus for adding material to the pulp or to the paper characterised by choice of auxiliary compounds which are added separately from at least one other compound, e.g. to improve the incorporation of the latter or to obtain an enhanced combined effect
  • D21H23/765—Addition of all compounds to the pulp
• • 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
  • D21H17/25—Cellulose
• • 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
  • D21H17/31—Gums
  • D21H17/32—Guar or other polygalactomannan gum
• • 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
  • D21H17/36—Polyalkenyalcohols; Polyalkenylethers; Polyalkenylesters
• • 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
  • D21H17/66—Salts, e.g. alums
• • 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
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/18—Paper- or board-based structures for surface covering
  • D21H27/22—Structures being applied on the surface by special manufacturing processes, e.g. in presses

Definitions

• the present invention relates to a new papermaking process in which a gelling system is used to improve the retention of the incorporated mineral fillers.
• the present invention also relates to a method of manufacturing paper using a gelling system which substantially improves the opacity of the paper obtained.
• the mechanical properties of the paper obtained are improved, for example the rigidity, and the tear resistance as well as other properties such as whiteness.
• the gelling system according to the invention can have advantages with regard to the quality and recyclability of white water from the paper manufacturing process as well as broken paper during the manufacturing process.
• Paper making poses many problems.
• One of the permanent concerns is to decrease the cost of paper by decreasing the quantity of cellulose fibers in the composition of the pulp.
• Another approach consists in reducing the concentration of aqueous discharges due to the increasingly severe environmental constraints.
• Papermakers have proposed various ways to reduce the cost of paper and try to improve its properties.
• One of the approaches used is the addition of inexpensive mineral fillers in the papermaking process to replace the fiber.
• certain mineral fillers are specifically used to improve certain properties of the paper.
• titanium oxide is used in its anatase and / or rutile forms to improve the opacity of papers. This is in particular the case of laminated papers commonly called decor paper.
• the Applicant has developed a new process for manufacturing paper using a gelling system which considerably increases the retention of mineral fillers, fibers and other materials in the paper sheet.
• Another object of the invention is to provide a gelling system and a paper manufacturing process in which the properties of the paper obtained, including the opacity yield of the mineral fillers, the tear resistance, the whiteness and other properties. necessary are improved, by optimizing the use of mineral fillers.
• Another object of the invention is to provide a paper having a high concentration of mineral fillers which has a tear resistance and other acceptable characteristics.
• the present invention is based on the development of a gelling system and of the process for manufacturing paper using it which markedly increase the retention of mineral fillers and other characteristics of the paper and which allows the optimization of the action. mineral fillers present within the pulp.
• the gelling system of the invention comprises:
• a polymer containing at least one hydroxyl group the amount of which is less than 5% by weight relative to the mineral fillers and the cellulose pulp, this polymer being chosen from the group consisting of: a polyvinyl alcohol,
• a crosslinking agent in aqueous solution comprising an element chosen from the group consisting of borate, zirconate, titanate and their mixture.
• crosslinking agent / polymer weight ratio containing at least one hydroxyl group being between 0.025 to 2.
• the amount of solids in the gelling system is from 0.02 to 18% by weight, preferably from 0.5 to 5% by weight, relative to the weight of the paper pulp or mother pulp.
• the mineral fillers used in the process are varied in nature and are chosen in particular according to the type of paper manufactured and its future use.
• the mineral filler material that can be used includes all common mineral fillers whose surface is at least partially anionic in character.
• mineral fillers non-limiting mention will be made of kaolin, clay, chalk, calcium carbonate, titanium dioxide, silica, and their mixture.
• the mineral fillers are normally added in the form of an aqueous dispersion at the appropriate concentrations specific to the type of paper manufactured.
• CMC carboxymethylcellulose
• EHEC ethyl-hydroxyethylcellulose
• HEC hydroxyethylcellulose
• MEC methylethylcellulose
• ethylhydroxyethylcellulose can come from the range of Blanose products from the company AQUALON and from the range of products
• a polyvinyl alcohol as a component of the gelling system, this will generally be used in the presence of borate.
• borate it will be chosen from the range of Mowiol products from the company HOESCHT or from the range of Rhodoviol products from the company RH ⁇ NE-POULENC.
• the polymer is selected from galactomannans comprising at least two vicinal hydroxyl groups, in particular, guars.
• galactomannans comprising at least two vicinal hydroxyl groups
• guars it has been observed that their reactive centers are particularly accessible, which makes it possible to use small quantities of them to achieve a satisfactory effect.
• the mineral charges are retained to a significant degree in the final product and the paper produced has improved resistance compared to a paper obtained from a process without gelling system.
• the guar used can be natural or chemically modified. Natural guar is extracted from the albumen of certain plant seeds, for example Cyamopsis Tetragonalobus.
• the guar macromolecule consists of:
• the polymer it will be formulated as an aqueous solution.
• the crosslinking agents are either prepared from basic products or commercial products are used.
• the borate ion is obtained for example from boric acid and sodium hydroxide or borax.
• the zirconate is prepared for example from zirconiu acetate, for example zirconium chloride.
• zirconiu acetate for example zirconium chloride.
• zirconium chloride for example zirconium chloride.
• the Zircomplex PN product from the company RH ⁇ NE-POULENC can be used.
• Titanate can be prepared, for example, from titanium bromide.
• the borate ion is used as crosslinking agent, in particular with a galactomannan comprising at least two vicinal hydroxyl groups, and more particularly with a guar.
• the possibility of adding mineral fillers to the paper pulp is limited by factors such as the retention of the fillers on the canvas, the dehydration of the paper pulp on the canvas, the wet and dry resistance of the paper obtained.
• the gelling system of the invention it has become possible to produce a paper which contains fewer fillers while retaining its opacity.
• the mechanical properties of the paper including the modulus of elasticity, the index of traction, absorption of traction energy, etc.
• the mechanical properties of the paper have values equal to or even greater than those achieved previously with papers obtained from conventional paper pulps.
• the sheet after drying, has greatly improved resistance characteristics when the method according to the invention is used. It has also been found that, when mineral fillers such as those mentioned above and the like are used in the paste, these mineral fillers are effectively retained in the sheet and moreover have no negative effect on the strength of the sheet, this in contrast to the sheets obtained by a manufacturing process without gelling system.
• the gelling system components and the fillers are added simultaneously or in any sequential order to the fiber dispersion before the sheet is formed in the paper machine. These components are added to a mixing tank or to a point in the system where there is appropriate agitation, so that they are dispersed properly.
• the gelling system and the fillers are mixed together and then added to the papermaking pulp before the sheet is formed.
• a portion of the mineral fillers preferably between 20 and 90%, is mixed in the mother paste, then, the gelling system is introduced and, after formation of the gel matrix, the mixture is added and mixed. rest of mineral charges in the mother paste before the formation of the sheet. The mother paste is then vigorously mixed before the paper is formed.
• the pH of the mother pulp is not excessively critical and is generally less than 11, and preferably between 5 to 9 .
• laminated paper commonly called decorative paper
• the majority of the fillers used is titanium dioxide, that is to say the level of titanium dioxide can reach
• the invention therefore also relates to laminated paper.
• the preparation of the paper is carried out in the presence of an agent for improving wet strength.
• Said agent consists for example of a quaternary ammonium salt of polymers based on epichlorohydrin, for example of polymers epichlorohydrin / dimethylamine.
• the invention also relates to laminates based on laminated papers, further containing at least one thermosetting resin (for example, resin of the type urea-formaldehyde, phenolic resin, resin of the melamine type or of the melamine-formaldehyde type, etc.) and at least one opacifying pigment such as titanium dioxide.
• thermosetting resin for example, resin of the type urea-formaldehyde, phenolic resin, resin of the melamine type or of the melamine-formaldehyde type, etc.
• opacifying pigment such as titanium dioxide.
• any process for preparing laminated paper known to those skilled in the art can be used to prepare laminates according to the invention.
• the invention is not limited to a particular process for the preparation of laminates.
• the first series of tests relates to the evaluation of the retention properties of the gelling system according to the invention during the papermaking process.
• the products used are commercial products:
• the titanium dioxide used in the examples is rutile titanium dioxide sold under the names of Rhoditan RL 18 by the company RH ⁇ NE-POULENC.
• the guar used in the examples is a guar marketed under the name of
• the zirconate comes from a commercial solution of a zirconium lactate complex Zircomplex PN from the company RH ⁇ NE-POULENC.
• the polyamino-amide-epichlorohydryne (PAE) used is the resin R4947 from the company CECA.
• the retention measurements were carried out according to the so-called "BRITT bowl” method. This method consists in measuring the chemical retention of the charges, avoiding the formation of the fibrous mat, responsible for mechanical retention by filtration effect. In fact, from a 500 ml sample of the fiber + fillers + additives to be tested dispersion, stirred, only the first 100 ml are drawn off through a sieve. By determining the respective amounts of fibers and fillers passed through the filtrate, the overall retention values (fibers + fillers) and load retention are reached by calculation.
• a filtration bowl was used fitted with a 610 ⁇ m opening grid.
• the cellulose (15 g) is defibrated beforehand in 500 ml of filtered water in a Dispermat bowl for 10 minutes at 3000 rpm.
• the guar (5% mother solution) and then the borate (2% borax mother solution) were introduced into the titanium dioxide slurry, anionic at pH 7, of the RL18 type with magnetic stirring.
• the fillers are mixed with the fiber in the Dispermat bowl for 5 min at 1000 rpm.
• the PAE is added, and the mixture is stirred for 30 seconds. Then, 100 ml of the mixture are drawn off (at 800 rpm) by gravity to allow good control of the sample flow rate (total opening of the valve).
• the overall retention rate is calculated according to the following formula: Overall ⁇ “P1-5p2) / Pl) * 100
• 500 ml p2 weight of the filtered and dried residue from the 500 ml sample
• the charges are frozen in the mass of the paper pulp by causing the pulp to be structured by the synergistic effect of the guar / borax gelling system.
• the opacity yield tests were carried out using formulas made with or without the gelling system of the invention, in order to know the spatial distribution of titanium dioxide in the dry sheet.
• the quantity of TiO 2 present in the sheet or ash rate is measured according to the method detailed below in paragraph 3.
• optical properties of the impregnated and pressed form were also measured according to the method of paragraph 4.
• the guar (at different% relative to the mineral fillers) was directly introduced into an aqueous or slurry dispersion of mineral fillers.
• the fillers are titanium dioxide, anionic at pH 7, Rhoditan RL18. It is the slurry thus formulated that we add to the dough. ii) Guar / zirconate gel
• the guar (at different% relative to the mineral fillers) was directly introduced into an aqueous or slurry dispersion of mineral fillers.
• the fillers are titanium dioxide, anionic at pH 7, Rhoditan
• the defibrated cellulose is diluted to 1 liter. Then, it is stirred in a mixer with paddle. Add the slurry, 37.5 g, then stir for 5 min. Finally, the whole is diluted to 4 liters in order to make grammage formulas at 80 g / m 2 . v) Manufacture of formettes
• test tube 500 ml of well homogenized suspension are taken in a test tube.
• PAE is added (commercial solution diluted 10 times to have an acceptable intake volume), ie 1 ml.
• the test tube is turned over several times to mix well.
• the contents of the test tube are poured into the bowl of the form filler filled with 6 liters of distilled water. It is mixed by bubbling for 10 s, it is left to stand for 10 s, then the form is made by drawing under vacuum. The form is then collected on a cardboard support, then placed in a vacuum dryer for 7 min.
• the quantity of Ti ⁇ 2 present in the sheet of 80 g / m 2 is measured by calcining a third of the form at 800 ° C for one hour.
• the percentage of Ti ⁇ 2 present in the sheet is thus calculated: c . . . / admir, ⁇ M after calcination ⁇ m empty
• the ash rate measures the quantity of mineral fillers present in the sheet. Retention is the expression of the proportion of mineral fillers retained in the sheet during its formation. This determination is made according to method NF 03-047 (Compendium of French Standards Paper, Cardboard, and Pulp: test methods, volume A, 4th edition, 1985).
• Strips of paper 7 cm by 10 cm are cut. The strips are then impregnated by capillary action by placing them for 1 minute on the resin. It is expressed between two glass rods and dried for 2 min in an oven at 120 ° C.
• the strips are impregnated a second time by immersion in the resin for 1 min.
• These sheets are fixed on a support formed from bottom to top of
• the opacity measurements on the laminates are made by evaluating the contrast ratio, for each of the papers to be tested, between the area on a kraft background and the area on a white background, using the "opacity" function of the Elrepho 2000 spectrocolorimeter of the DATACOLOR company.
• the gelling system increases the retention of charges, in particular by the formation of large structures which are better retained.
• the gelling system also increases opacity. Large structures formed of charges are better distributed spatially in the sheet of paper.
• the gelling system increases charge retention and opacity, in particular by the formation of large loose structures which are better retained and which better distribute the charges in space.
• Figure n ° 1 retention of fillers (Britt bowl) as a function of the borax / guar ratio.
• the and ---. represent systems containing respectively 1, 5% and 6% of guar with respect to Ti ⁇ 2.
• Figure n ° 4 breaking force as a function of the ratio r
• the * • and B represent respectively 0.5% and 1.5% of guar compared to Ti ⁇ 2-

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• 1997
  • 1997-06-04 FR FR9706949A patent/FR2764313B1/fr not_active Expired - Fee Related
• 1998
  • 1998-06-03 SK SK1650-99A patent/SK165099A3/sk unknown
  • 1998-06-03 WO PCT/FR1998/001120 patent/WO1998055694A1/fr not_active Application Discontinuation
  • 1998-06-03 EP EP98929474A patent/EP0985069A1/de not_active Withdrawn
  • 1998-06-03 AU AU79221/98A patent/AU7922198A/en not_active Abandoned
  • 1998-06-03 CN CN98807014A patent/CN1262715A/zh active Pending
  • 1998-06-03 ID IDW991517A patent/ID23381A/id unknown
  • 1998-06-03 HU HU0002293A patent/HUP0002293A3/hu unknown

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