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
  • D21H17/03—Non-macromolecular organic compounds
  • D21H17/05—Non-macromolecular organic compounds containing elements other than carbon and hydrogen only
  • D21H17/17—Ketenes, e.g. ketene dimers
• • 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
  • D21H21/14—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 characterised by function or properties in or on the paper
  • D21H21/16—Sizing or water-repelling agents

Definitions

• the present invention relates to a method for producing a paper grade having additives in its furnish, in which method alkaline hydrophobizing paper sizes are used. These sizes have a reactive functional group capable of forming covalent bonds with cellulose fiber and such hydrophobic tails thereof that are directed outward from said fiber.
• Ink-jet printing may be implemented in two basic variants: continuous-jet and dot-on-demand (DOD) printers.
• DOD dot-on-demand
• the applications of ink-jet printers today cover a wide range of applications from monochrome office printers to four-colour photographic-quality printers, on-line identification and marking devices and very-lar- ge-format sheet/roll medium plotters.
• ink-jet printing has the greatest number of different applications.
• the particular assets of ink- jet printing are found in its multicolour capability and printing speed.
• the costs involved in this printing method are also comparative low.
• the printing process may be readily controlled from the computer system, whereby all the facilities of data processing techniques are easily available. For instance, colour rendition and adjustment of colour balance can be simply controlled with the help of the data-processing system.
• printing quality is affected by the fiber composition, and thereby chiefly by the ratio of coniferous to deciduous wood.
• the structure and topography of pores in the finished sheet are crucial to the outcome of the printing process in the discussed method.
• the printing result is determined by the non- compressible grain of the sheet and other parameters characterizing the ink absorption capability of the sheet.
• a paper grade optimized for ink-jet printing is required to have a sufficient capability of adsorbing the printing ink, yet permitting the ink to dry at a sufficiently fast rate before the ink can spread along the fibers or into the pores of the sheet structure. Thence, the surface- chemical interactions of the sheet with the ink are accentuated in ink-jet printing.
• the quality of ink-jet printing can be modified by means of additives used in papermaking such as hydrophobizing internal sizes and surface size formulations, surface size starches and pigments of high sur- face area .
• Formulations for paper sizing have been developed in the art with the aim of modifying the surface-chemical prop- erties of the paper and improving the black-and-white monochrome printing quality by virtue of increasing the hydrophobicity of the paper.
• elevating the hydrophobicity of the paper it has been possible to achieve a better printing result of black ink on the sheet through improved control of ink absorption under capillary forces into the sheet structure in both the lateral and the depth directions of the sheet. This approach has resulted in a sharply defined printing pattern and elimination of black ink spread (wicking) on the sheet.
• ASA alkenylsuccinic acid anhydrides
• ALD alkylketene dimers
• alkylketene dimer sizes containing one -lactone ring are made by dimerization from two saturated straight-chain fatty acid chlorides; the most commonly used alkylketene dimer sizes being made from palmitic and/or stearic acid.
• Alkenyl succinic acid anhydrides, or ASA compounds are obtained as the reaction products of long-chain olefins (C I5 - C 20 ) with maleic acid anhydride.
• a good ink- jet printability is achieved by incorporating into the paper a size based on 2-oxetanone, and made starting from one or a greater number of fatty acids having main chain comprising 6-22 carbons linked with each other by saturated bonds, and said acid(s) including at least one with a branched carbon chain.
• 2-oxetanone produced from saturated fatty acids, of which at least one posses a branched carbon chain.
• these novel sizes may be made starting from fatty acids, whereby it is essential that at last one of the fatty acids have a branched carbon chain, which chains, however, contains no double bonds .
• the length of the carbon chain in the starting material fatty acids may vary in the range from 6 to 22 carbons.
• the invention also relates to a paper grade manufactured by treating with a size formulation based on 2-oxetanone manufactured from fatty acids of which at least one posses a branched carbon chain.
• the paper may contain alum and precipitated calcium carbonate (PCC) .
• Stable emulsions of the novel sizes can be made in the same manner as standard AKD emulsions.
• the paper grade according to the present invention is generally sized so that at least 200 g, advantageously at least 600 g, and most advantageously at least 1 kg of size is added per ton of paper.
• the paper grade thus manufactured can be optimized for ink-jet printing, whereby it may also be used in copiers and laser printers (as a "multipurpose" paper) .
• the paper grade manufactured according to the invention is capable of serving the needs of ink-jet printing with both black and colour inks without involving the problems normally associated with ink-jet printing.
• the paper grade according to the invention achieves a balanced compromise in the adsorption and hydrophobicity qualities of the paper so that a high-quality printing result is achieved with both black and colour inks (that is, the benefits include minimal show-through, high printing density, no wicking, no bleeding, and minimal raggedness of the printed contours when printing with a black ink or colour on colour.
• the paper grade according to the invention is capable of meeting the requirements set for a printer paper grade in office use, and besides, serving as a "multipurpose" paper.
• the size formulations according to the in- vention make it possible to attain a desirable end result in ink-jet printing with a smaller amount of size dosing than is that required with conventional AKD sizes, whereby the problems of paper machine contamination and adher- ence of dirt and fuzz to rolls plaguing conventional AKD sizes can be avoided.
• One type of size formulation according to the present invention is a 2-oxetanone size made starting from iso- stearic acid or a mixture of fatty acids advantageously containing at least 40 % of isostearic acid or some other fatty acid with a branched carbon chain.
• test sheets of 80 g/m 2 basis weight were first made according to standardized SCAN test methods using a circulating water sheet mould, a wet press and a drying cylinder.
• the pulp slurry was prepared using birch/pine pulp in the ratio of 60/40, internal size starch Raisamyl 135 ESP (by Raisio Chemicals Oy) by 0.3 % of fiber weight, PCC filler by 22 % of sheet weight and retention agents by a 0.16 % overall amount of fiber weight.
• the internal sizes were dosed into the pulp slurry by 0.06, 0.12 and 0.20 % of fiber weight.
• the ready-made test sheets were tested in the Cobb 60 water absorption test and the Schroder ink penetration test immediately after drying, the next day prior to curing and after drying and curing.
• the curing was performed by keeping the test sheets for 10 min at 105 °C in a heat chamber .
• the comparative size formulation in the example was a conventional AKD size (Raisafob 5105) .
• the isostearic- acid-based AKD size was dispersed in the same fashion as the conventional AKD size using cationic starch,
• the iso- stearic-acid-based AKD size (50/50 ratio of branched/non- branched carbon chains) achieves a sizing quality comparable with that available by conventional sizes based on a mixture of palmitic/stearic acids.
• AKD sizes were also evaluated in a pilot-scale paper machine running 60 m/min (4.1 kg/min) and producing fine-grade paper with a basis weight of 80 g/m 2 .
• the pulp constituents in the pilot-scale test machine run were as follows: birch/pine pulp mixed in ratio 75/25 and beaten to a freeness of 25 °SR.
• the filler was precipi- tated calcium carbonate (PCC) by 22 % of paper weight.
• the internal size starch was Raisamyl 135 (Raisio Chemicals) by 0.5 % of fiber weight and the retention agents were used by a 0.22 % overall amount of fiber weight.
• the surface size was Raisio Chemicals' Raisamyl 408 SP surface size starch, and it was used in a consistency of 8 % on dry weight basis.
• the hydrophobicity of the sheet manufactured in the pilot-scale paper machine was tested by the Cobb 60 water absorption test using samples taken immediately from the Pope winder and conditioned for 10 min before the test. Additionally, the hydrophobicity of the sheet made in the pilot-scale machine was tested using roll-cured samples in both the Cobb 60 absorption test and the HST ink penetration test.
• the HST test is based on the penetration of ink into the sheet, monitored from the reflectance of an ink spot in a given time, e.g., the time during which the reflectance falls to 80 % of its initial value.
• the compatibility of the paper samples with ink-jet printing were tested using a commercial- grade ink-jet printer (manufactured by Hewlett-Packard) . The wicking and bleeding qualities of the printing result were evaluated from the printed test sheets both visually and using an image analysis facility and by measuring the optical densities of the printed colour areas.
• the iso- stearic-acid-based AKD size with a 50/50 ratio of branched/non-branched carbon chains in black-and-white printing achieves an optimal balance between the parameters characterizing the raggedness of the printed contour (test pattern bleeding, wicking, area and perimeter) and size consumption.
• the surface sizing according to the present invention is performed without using conventional hydrophobizing agents or other surface-hydrophobizing techniques.
• An internal size according to the invention was further tested in a paper machine making fine-grade paper in an industrial scale.
• the comparative samples of the test were made using a conventional AKD size.
• the composition of the manufactured paper was equivalent to a typical fine-grade paper containing precipitated calcium carbonate (PCC) , thus being suitable for use in ink-jet printing.
• the basis weight of the paper made in the test run was 70 g/m 2 .
• the amount of added size of 1.3 kg/ton of paper .
• Sheet samples taken from a number of machine rolls pro- **d during the test run were analyzed from their top sides for hydrophobicity (Cobb 60 and HST) and parameters (wicking, bleeding and optical densities) characterizing compatibility with ink-jet printing.
• a paper grade was surface treated, for which paper already a certain degree of hydrophobicity was developed by internal sizing of the paper in the slurry stage of its manufacture.
• the hydrophizing effect was on the level of 30 g/m 2 according to Cobb 60 .
• the surface sizing of the paper was effected using a Helicor- device, where the paper sheet to be treated lays on a rotatable drum, and where a surface sizing starch together with a incorporated surface hydrophobizing agent can be applied using a selected blade pressure.
• the surface sizing starch used in this example was an oxidated cationic surface starch as a 10 % solution (Raisamyl 406 SP, Raisio Chemicals Oy) .
• This starch solution with a 10 % consistency was admixed with surface size additives in different amounts calculated on the basis of the active agent on the starch dry matter.
• surface size additive was tested isostearine-stearine acid AKD, styrene aerylate and SMA surface size additives. Isostearine-stearine acid (i.e. branched-non- branched chain) relation in the AKD size was 1:1.
• Raisafob P400 As styrene acrylate was used the size Raisafob P400 (Raisio Chemicals Oy) .
• the SMA used was styrene maleic anhydride, fabricated by Raisio Chemicals and marketed under the name Raisafob D100.
• the test results are given in the following table 5, where the sizing results are given in Cobb 60 and HST- values.
• test results used for the evaluation of the black and white printability are given in the following table 6.
• the paper probes were printed using a ink-jet printer of the type of Hewlett-Packard 500 C, and the optical den- sities of the prints were measured.
• the surface size additives were tested also on a pilot paper machine, where a paper grade having no preliminary surface sizing was sized using a pond size press and a film size press.
• the paper furnish consisted of a fine paper grade with the grammage of 80 g/m 2 , and it contained 20 % of precipitated calcium carbonate as filler of the paper furnish (a common multipurpose office paper) .
• the surface size used was oxidated cationic surface size (Raisamyl 405 SP, Raisio Chemicals Oy) as a 8% consistency solution.
• the surface size starch was admixed with different hydrophobizing surface size additives: elementary AKD (palmitic/stearic acid, 60/40 %) , isostearic- stearic acid AKD (branched/non-branched, 50/50 %) , styrene-acrylate (Raisafob P400, Raisio Chemicals Oy) and SMA based (styrene maleic anhydride, Raisafob D100, Raisio Chemicals Oy) surface size additives.
• elementary AKD palmitic/stearic acid, 60/40 %)
• isostearic- stearic acid AKD branched/non-branched, 50/50 %)
• styrene-acrylate Rostyrene-acrylate
• SMA styrene maleic anhydride
• the following table 7 contains the test results received on a pilot paper machine, where a film size press was used.
• Table 8 contains results received on ink- jet printing of paper probes, where a HP 560 C printer was used in the printing. The print results were analyzed according to a dry evaluation method. Table 8, Black and white printability in a HP 560 C printer

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• Paper (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)

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Citations (5)

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• 1998
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  • 1998-03-11 JP JP54016298A patent/JP3851988B2/ja not_active Expired - Fee Related
  • 1998-03-11 WO PCT/FI1998/000212 patent/WO1998041686A1/en active IP Right Grant
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  • 1998-03-11 AT AT98909511T patent/ATE540162T1/de active
  • 1998-03-11 ID IDW990996A patent/ID22448A/id unknown
  • 1998-03-11 RU RU99122038/12A patent/RU2198975C2/ru not_active IP Right Cessation
  • 1998-03-11 AU AU64016/98A patent/AU725352B2/en not_active Ceased
  • 1998-03-11 CA CA002283962A patent/CA2283962C/en not_active Expired - Fee Related
  • 1998-03-11 EP EP98909511A patent/EP0975836B1/en not_active Expired - Lifetime
  • 1998-03-11 PL PL335641A patent/PL192636B1/pl unknown
  • 1998-03-11 NZ NZ337653A patent/NZ337653A/xx unknown
  • 1998-03-11 CN CN98803299A patent/CN1098394C/zh not_active Expired - Fee Related
  • 1998-03-11 ES ES98909511T patent/ES2378412T3/es not_active Expired - Lifetime
  • 1998-03-11 BR BR9808335-0A patent/BR9808335A/pt not_active IP Right Cessation
  • 1998-03-13 ZA ZA982148A patent/ZA982148B/xx unknown
  • 1998-03-17 TW TW087103905A patent/TW405003B/zh not_active IP Right Cessation
• 1999
  • 1999-09-13 NO NO19994439A patent/NO328510B1/no not_active IP Right Cessation

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