Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5218—Macromolecular coatings characterised by inorganic additives, e.g. pigments, clays
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/0011—Pre-treatment or treatment during printing of the recording material, e.g. heating, irradiating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5227—Macromolecular coatings characterised by organic non-macromolecular additives, e.g. UV-absorbers, plasticisers, surfactants
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5254—Macromolecular coatings characterised by the use of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers

Definitions

• the present disclosure relates generally to methods of improving sheet gloss.
• Recent trends in digital printing technology include utilizing inkjet inks in high-speed digital commercial or industrial printers.
• Inkjet inks are often aqueous based inks, which contain a minor amount of colorant and a large amount of water and co-solvent(s).
• a medium having suitable absorption properties As such, in high-speed digital inkjet printing, it is desirable to utilize a medium having suitable absorption properties.
• the medium used inkjet printing determines, at least in part, the quality of the image printed thereon. When the absorption properties of the medium are poor, the quality of the resulting image is often poor as well.
• an ink-receiving layer is included which improves the ink receptive properties of the medium.
• Fig. 1 is a flow diagram illustrating an example of a method for improving sheet gloss.
• Examples of the recording medium disclosed herein include one layer that functions as both an ink-receiving layer and a coating layer.
• the single ink- receiving and coating layer imparts a high ink adsorption rate (i.e., fast absorption of the liquid component in the ink, e.g. water) and exhibits improvements in image qualities after printing, including reduced graininess, improved image gloss, low ink bleed, low mottle, high gamut, and high black optical density.
• Examples of the recording medium disclosed herein are also subjected to a calendering process that utilizes specific pressure and temperature conditions, which are relatively high compared to standard calendering conditions.
• the level of calendering disclosed herein unexpectedly results in the recording medium having desirable print quality (e.g., low ink bleed, etc.) as well as desirably high (>40) sheet gloss levels.
• desirable print quality e.g., low ink bleed, etc.
• desirably high (>40) sheet gloss levels e.g., high ink bleed, etc.
• the single ink-receiving and coating layer disclosed herein achieved desirable gloss without a second layer (i.e., without an additional ink-receiving layer), and also provides desirable absorption after the calendering process is performed, which is in contrast to other recording sheets that suffer from poor absorption as a result of over calendering.
• the recording medium includes a base.
• the base is a supporting substrate upon which the single ink-receiving and coating layer is formed.
• the base may be in the form of a sheet or a continuous web suitable for use in an inkjet printer.
• the base is a base paper manufactured from cellulose fibers. More specifically, the base paper may be produced from chemical pulp, mechanical pulp, thermal mechanical pulp and/or the combination of chemical and mechanical pulp.
• the base paper may also include additives, such as internal sizing agents and/or fillers. When utilized, the internal sizing agents are added to the pulp before it is converted into a paper web or substrate. Any suitable internal sizing agent may be selected, such as alkyl succinic anhydride, diketene, and rosin.
• the base may be an uncoated raw base or a pre-coated base.
• the pre-coated base includes a pre-coating that is established on the raw base.
• the pre-coating may include any of a variety of inorganic pigment coatings applied in-line or offline using a size press, a gateroll press or any variety of blade coater.
• a pre- coat may be from about 5 gsm to about 10 gsm of calcium carbonate with a binder, such as polyvinyl alcohol or latex.
• the single ink-receiving and coating layer is established directly on the base (i.e., on the raw base or on the pre-coating of the base). It is to be understood that this single layer is one layer that contains the coating composition disclosed herein.
• the single layer may have any desirable thickness, and in some instances may include multiple sub-layers to achieve the desirable thickness. However, the single layer acts as both the ink-receiving layer and the coating layer, and thus the recording medium does not include any other layers on the single layer. As such, the single ink-receiving and coating layer is the outermost layer of the recording medium.
• the single ink-receiving medium and coating layer is made up of an aqueous pigmented dispersion composition that includes both modified calcium carbonate (MCC) and precipitated calcium carbonate (PCC).
• MCC modified calcium carbonate
• PCC precipitated calcium carbonate
• the modified calcium carbonate used herein refers to pre-existing calcium carbonate (ground or precipitated) which has been post-treated with phosphoric acid and CO 2 gas as well as a variety of other additives (such as soluble silicates) for the purpose of altering both the structure and the chemical composition of the original particle.
• the post-treatment of the calcium carbonate results in a pigment particle made up of a shell of various calcium compounds surrounding a core of the original carbonate molecule.
• Suitable MCC material may take the form of a slurry dispersion of structured calcium minerals, which include primarily calcium
• Calcium phosphate includes compounds containing calcium ions together with phosphate ions, and may include octacalcium phosphate (Ca8H 2 (PO 4 )6-5H 2 O) or other forms of calcium phosphate.
• octacalcium phosphate is OMYAJET® 5010 available from Omya Inc.
• the amount of modified calcium carbonate pigment included in the composition ranges from about 15 dry parts to about 25 dry parts of the total dry parts of the composition. Precipitated calcium carbonate pigments may be obtained by calcining crude calcium oxide.
• Precipitated calcium carbonate is commercially available, for example, under the tradename OPACARB® A40 (Minerals Technologies Inc.).
• the amount of precipitated calcium carbonate used in the composition ranges from about 75 dry parts to about 85 dry parts.
• the total amount of inorganic pigments present in the coating composition ranges from about 60 wt.% to about 90 wt.%.
• Wt.% refers to dry weight percentage based on the total dry weight of the coating composition.
• the composition excludes clay.
• the composition disclosed herein develops desirable gloss (due, at least in part, to the calendering process) and maintains sufficient coating openness for adequate absorption without the use of clay.
• clay such as calcined clay, kaolin clay, or other phyllosilicates, may be included. Clay(s), in some instances, may be added to further increase the gloss and/or increase the absorption rate. As an example, calcined clay may be desirable to further enhance the absorption rate of the single ink-receiving and coating layer.
• the calcined clay(s) may be added in an amount ranging from about 0.5 dry parts to about 10 dry parts (based on the total parts of inorganic particles).
• the uncalcined clay(s) may be added in an amount ranging from about 0.5 dry parts to about 5 dry parts (based on total parts of inorganic particles).
• the coating composition disclosed herein may also include a polymeric co- pigment.
• suitable polymeric co-pigments include plastic pigments (e.g., polystyrene, polymethacrylates, polyacrylates, copolymers thereof, and/or combinations thereof).
• Suitable solid spherical plastic pigments are commercially available from The Dow Chemical Company, e.g., DPP 756A and HS 3020.
• the amount of polymeric co-pigment in the coating composition may be in the range of 1 dry part to 10 dry parts based on 100 parts of inorganic pigments. In an example, the amount of polymeric co-pigment or plastic pigments ranges from about 3 dry parts to about 7 dry parts per 100 parts of inorganic pigments.
• the coating composition also includes a binder.
• the binder(s) may be hydrophilic or water-soluble binders such as polyvinyl alcohol (e.g., MOWIOL® 15- 98, Kuraray) and derivatives thereof (e.g. carboxylated polyvinyl alcohol, sulfonated polyvinyl alcohol, acetoacetylated polyvinyl alcohol, and mixtures thereof), polystyrene-butadiene, polyethylene-polyvinyacetate copolymers, starch, gelatin, casein, alginates, carboxycellulose materials, polyacrylic acid and derivatives thereof, polyvinyl pyrrolidone, casein, polyethylene glycol, polyurethanes (for example, a modified polyurethane resin dispersion), polyamide resins (for instance, an epichlorohydrin-containing polyamide), a polyvinyl pyrrolidone-vinyl acetate) copolymer, a polyvinyl acetate-
• the binder is present in an amount sufficient to bind the inorganic pigments.
• the total amount of binder is present in an amount ranging from about 5 to about 20 parts based on 100 parts of inorganic pigments.
• the coating composition includes from about 3 dry parts to about 10 dry parts of a latex binder and from about 2 dry parts to about 7 dry parts of a polyvinyl alcohol binder.
• the coating composition may also include other coating additives such as calcium chloride, surfactants, rheology modifiers, defoamers, optical brightening agents, sheet color adjusting agents, biocides, pH controlling agents, dyes (e.g., violet dye), and other additives for further enhancing the properties of the coating.
• the total amount of coating additives may be in the range of 0 to about 10 parts based on 100 parts of inorganic pigments.
• the coating composition includes from about 8 dry parts to about 10 dry parts of calcium chloride (CaC ), from about 0.3 dry parts to about 0.4 dry parts of a defoaming agent (e.g.,
• AGITANTM 103, Munzing from about 0.004 dry parts to about 0.006 dry parts of a sheet color adjusting agent (e.g., CATERENTM Violet 79732, Clariant), and from about 0.4 dry parts to about 0.6 dry parts of an optical brightening agent (e.g., TINOPAL®, BASF Corp.).
• a sheet color adjusting agent e.g., CATERENTM Violet 79732, Clariant
• an optical brightening agent e.g., TINOPAL®, BASF Corp.
• Water is added to the inorganic pigments and other components in order to form the coating composition.
• the amount of water added may depend, at least in part, on the desirable solids percentage for the final coating composition. In an example, enough water is added to obtain composition including from about 40% solids to about 55% solids.
• the composition is established directly on the base to form the recording medium.
• the coating composition may be applied to one or both opposing sides of the base.
• the double-side coated recording medium has a sandwich structure, i.e., both sides of the supporting base are coated with the same coating, and both sides may be printed with images or text.
• the coat weight of the single ink-receiving and coating layer may be in the range of about 4 gsm (grams per square meter) to 45 gsm per side. In an example, the coat weight of the single ink-receiving and coating layer may be in the range of about 4.5 gsm to about 30 gsm per side.
• the coating composition of the present disclosure may be applied to the base using any one of a variety of suitable coating methods, such as blade coating, jet blade coating, air knife coating, metering rod coating, curtain coating, or another suitable technique.
• suitable coating methods such as blade coating, jet blade coating, air knife coating, metering rod coating, curtain coating, or another suitable technique.
• both sides of the base may be coated during a single manufacture pass, or alternatively, each side may be coated in separate passes.
• the coated base is then subjected to a drying process to remove water and other volatile components from the ink-receiving and coating layer and the base.
• the drying means includes, but is not limited to, infrared (IR) dryers, hot surface rolls, and hot air flotation dryers.
• the recording medium is calendered to increase glossiness (reference numeral 102 in Fig. 1 ).
• Calendering may be accomplished using an on-line or an off-line calender machine, which may be a soft-nip calender or a supercalender.
• the rolls e.g., a stainless steel roll positioned against a cotton-filled backing roll
• the calendering process disclosed herein is performed at a pressure ranging from about 1200 PLI (pressure per linear inch) to about 1500 PLI (i.e., about 3000 psi (pressure per square inch) to about 3500 psi) and at a temperature ranging from about 85°C to about 95°C.
• the calendering process is performed for a number of passes ranging from 2 to 5 (reference numeral 104 in Fig. 1 ). This calendering process unexpectedly results in desirable sheet gloss (>40), while not sacrificing printability and print quality. In particular, it has been found that the calendering process disclosed herein does not negatively impact the printability because the process does not close up the structure of the coating.
• composition was generated utilizing the components shown in Table 1 The composition had a total solids amount of 44.5 wt%. Table 1
• the composition was coated on a pre-coated offset base via blade coating to form a recording medium having a single ink receiving and coating layer on the pre-coated base.
• the composition was coated at 7 gsm on 90 gsm of the pre- coated base.
• the recording medium was calendered according the examples disclosed herein using a heated 2 roll calender from Independent Machine Co., Fairfield, NJ.
• the recording medium was calendered at 3000 psi ( ⁇ 1286 PLI) and at about 90°C for 2 passes.
• the sheet gloss level of the calendered recording medium was measured at a 75° measurement angle using a Micro gloss 75, which is a gloss meter available from BYK-Gardner.
• the sheet gloss in this example was 60, which was well above a suitable sheet gloss level of 40.
• a print was generated using the recording medium generated in Example 1 .
• Standard ink for a T300 webpress printer was utilized, and the ink was printed using a testbed printer that approximates the general webpress print conditions with drying.
• the print was tested for gamut, black optical density (KOD), image gloss, and black-to-yellow ink bleed. These results are shown in Table 2.
• Bleed was tested using an Image Analyzer from QEA Inc., and was also visually evaluated after printing. The bleed measurement was 4 mils, which is well below an acceptable level of less than 10 mils of color to color bleed. Color gamut and black optical density (KOD) were measured using an X-Rite 938
• compositions (A and B) were generated utilizing the components shown in Table 3. Each of the compositions had a total solids amount of 44.5 wt%. Table 3
• composition A and composition B were coated on a respective uncoated base via blade coating to form, respectively, recording medium A and recording medium B, each having a single ink receiving and coating layer on the uncoated base.
• the respective compositions were coated at 7 gsm on 56 gsm of the respective uncoated bases.
• Recording medium A and recording medium B were calendered according the examples disclosed herein using a heated 2 roll calender from Independent Machine Co., Fairfield, NJ. Recording medium A was calendered at 3500 psi
• Recording medium B was calendered at 3500 psi (-1500 PLI) and at about 90°C for 3 passes.
• the sheet gloss level of the calendered recording mediums A and B was measured at a 75° measurement angle using a Micro gloss 75, which is a gloss meter available from BYK-Gardner.
• the sheet gloss for both recording medium A and recording medium B was 51 , which was well above a suitable sheet gloss level of 40. It is believed that the higher latex amount in recording medium B also improved the sheet gloss, thus requiring less calendering passes.
• ranges provided herein include the stated range and any value or sub-range within the stated range.
• a range from about 75 parts to about 85 parts should be interpreted to include not only the explicitly recited limits of about 75 parts to about 85 parts, but also to include individual values, such as 76 parts, 80 parts, 82.5 parts, etc., and sub-ranges, such as from about 77 parts to about 83 parts, from about 80 parts to about 84 parts, etc.
• “about” is utilized to describe a value, this is meant to encompass minor variations (up to +/- 10%) from the stated value.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Paper (AREA)

Applications Claiming Priority (1)

Publications (3)

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Family Applications (1)

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• 2011
  • 2011-11-29 WO PCT/US2011/062352 patent/WO2013105912A2/en active Application Filing
  • 2011-11-29 EP EP11879159.9A patent/EP2785530B1/de not_active Not-in-force

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