WO2016110711A1 - Compositions de revêtement - Google Patents

Compositions de revêtement Download PDF

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Publication number
WO2016110711A1
WO2016110711A1 PCT/GB2016/050042 GB2016050042W WO2016110711A1 WO 2016110711 A1 WO2016110711 A1 WO 2016110711A1 GB 2016050042 W GB2016050042 W GB 2016050042W WO 2016110711 A1 WO2016110711 A1 WO 2016110711A1
Authority
WO
WIPO (PCT)
Prior art keywords
equal
coating composition
paper
coated
example equal
Prior art date
Application number
PCT/GB2016/050042
Other languages
English (en)
Inventor
Janet Preston
Gavin BUTLER-LEE
Original Assignee
Imerys Minerals Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Imerys Minerals Limited filed Critical Imerys Minerals Limited
Priority to EP16700665.9A priority Critical patent/EP3242970A1/fr
Priority to JP2017536531A priority patent/JP2018508607A/ja
Priority to MX2017009027A priority patent/MX2017009027A/es
Priority to BR112017014715A priority patent/BR112017014715A2/pt
Publication of WO2016110711A1 publication Critical patent/WO2016110711A1/fr

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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
    • D21H19/38—Coatings with pigments characterised by the pigments
    • D21H19/385—Oxides, hydroxides or carbonates
    • 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
    • D21H19/40—Coatings with pigments characterised by the pigments siliceous, e.g. clays
    • 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
    • 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
    • D21H19/54—Starch
    • 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 present invention relates generally to coating compositions for coating paper.
  • the present invention also relates to paper coated with said coating compositions and to methods of making said coating compositions and said coated paper.
  • the present invention further relates to a method of printing comprising applying ink to said coated paper.
  • Paper may be coated with various coating compositions to provide the paper with certain properties that make it suitable for particular uses.
  • An ink jet printer operates by ejecting droplets of dye or pigment suspended in aqueous or solvent-based medium from a nozzle onto a substrate such as paper. Each droplet adheres to the paper as a dot and a collection of dots form a printed image.
  • the ink is applied to the paper, it will remain in a well focussed symmetrical dot.
  • the ink should not be absorbed too deeply by the paper or optical density will be lost at the paper surface and the dot of ink may be spread out in an irregular manner to cover a larger area than intended and appear rough at the edges. It is also desirable for the ink to dry quickly to avoid smudging.
  • An acceptable combination of properties e.g. print density, print index, line and edge quality, smudge index
  • a coating composition comprising a binder, an alkali earth metal compound and an anionic dispersant.
  • the coating composition optionally comprises a cationic polymer and the coating composition has a solids content of at least about 45 wt% and a Brookfield viscosity equal to or less than about 1500 mPa.s.
  • a coating composition comprising a binder, an alkali earth metal compound, an anionic dispersant and optionally a cationic polymer, wherein the coating composition has a solids content of at least about 45 wt% and a Brookfield viscosity equal to or less than about 1500 mPa.s.
  • the coating composition comprises 0 wt% cationic polymer.
  • a coating composition comprising a binder, an alkali earth metal compound and an anionic dispersant, wherein the coating composition comprises 0 wt% cationic polymer.
  • the coating composition consists essentially of or consists of the binder, the alkali earth metal compound and the anionic dispersant.
  • the alkali earth metal compound has a dso equal to or greater than about 0.4 pm and/or a BET specific surface area of less than about 40 m 2 /g.
  • a coating composition comprising a binder, an alkali earth metal compound and an anionic dispersant, wherein the alkali earth metal compound has a dso equal to or greater than about 0.4 pm and/or a BET specific surface area of less than about 40 m 2 /g.
  • a paper comprising a fibrous substrate coated with a coating composition, wherein the coating composition comprises a binder, an alkali earth metal compound and an anionic dispersant.
  • the coating composition may, for example, be in accordance with any of the aspects or embodiments described herein.
  • a method of making a coating composition comprising combining a binder, an alkali earth metal compound and an anionic dispersant.
  • the coating composition may, for example, be in accordance with any of the aspects or embodiments described herein.
  • the alkali earth metal compound, the anionic polymer, any optional additional inorganic particulate material and any optional cationic polymer may be combined into a first composition (e.g. aqueous slurry) before this first composition is combined with the binder to make the coating compositions described herein.
  • the optional additional inorganic particulate material may, for example, be combined with the first composition to form a second composition before the second composition is combined with binder to make the coating compositions described herein.
  • a composition comprising an alkali earth metal compound, an anionic polymer, optionally a cationic polymer and optionally a further inorganic particulate material.
  • a method of making a coated paper comprising coating a fibrous substrate with a coating composition, wherein the coating composition comprises a binder, an alkali earth metal compound and an anionic dispersant.
  • the coating composition may, for example, be in accordance with any of the aspects or embodiments described herein.
  • a method of printing comprising applying ink to a coated paper, wherein the coated paper comprises a fibrous substrate coated with a coating composition, wherein the coating composition comprises a binder, an alkali earth metal compound and an anionic dispersant.
  • the coating composition may, for example, be in accordance with any of the aspects or embodiments described herein.
  • the alkali earth metal compound is an alkali earth metal carbonate.
  • the alkali earth metal compound is calcium carbonate.
  • the alkali earth metal carbonate is precipitated calcium carbonate (PCC).
  • the cationic polymer is present in the coating composition in an amount equal to or less than about 2 wt% relative to the total weight of inorganic particulate material in the composition.
  • the cationic polymer is present in the coating composition in an amount equal to or less than about 1 wt% relative to the total weight of inorganic particulate material in the composition.
  • there is no cationic polymer present in the coating composition i.e. the cationic polymer is present in the composition in an amount of 0 wt%.
  • the alkali earth metal compound e.g. calcium carbonate such as PCC
  • the alkali earth metal compound has a dso equal to or greater than about 0.4 pm.
  • the alkali earth metal carbonate e.g. calcium carbonate such as PCC
  • the alkali earth metal carbonate has a dso equal to or greater than about 0.6 pm.
  • the alkali earth metal carbonate e.g. calcium carbonate such as PCC
  • the alkali earth metal carbonate e.g. calcium carbonate such as PCC
  • the alkali earth metal compound e.g. calcium carbonate such as PCC
  • the alkali earth metal compound has a BET specific surface area less than about 40 m 2 /g. In certain embodiments, the alkali earth metal compound (e.g. calcium carbonate such as PCC) has a BET specific surface area equal to or less than about 30 m 2 /g. In certain embodiments, the alkali earth metal compound (e.g. calcium carbonate such as PCC) has a BET specific surface area equal to or less than about 20 m 2 /g. In certain embodiments, the alkali earth metal compound (e.g. calcium carbonate such as PCC) has a BET specific surface area equal to or less than about 10 m 2 /g.
  • the coating composition further comprises an aluminosilicate.
  • the aluminosilicate is kaolin.
  • the aluminosilicate is calcined kaolin.
  • the aluminosilicate is hydrous kaolin.
  • the weight ratio of alkali earth metal compound to aluminosilicate ranges from about 60:40 to about 95:5. In certain embodiments, the weight ratio of alkali earth metal compound to aluminosilicate ranges from about 70:30 to about 90:10. In certain embodiments, the weight ratio of alkali earth metal compound to aluminosilicate is about 85: 15.
  • the binder is a cationic binder.
  • the binder is starch. In certain embodiments, the binder is cationic starch.
  • the anionic dispersant is a homopolymer and/or a copolymer of (meth)acrylic acid. In certain embodiments, the anionic dispersant is a homopolymer of acrylic acid.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a black print density equal to or greater than about 1.0. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a black print density equal to or greater than about 1.1. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a black print density equal to or greater than about 1.2.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a magenta print density equal to or greater than about 0.7. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a magenta print density equal to or greater than about 0.8. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a magenta print density equal to or greater than about 0.9.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a cyan print density equal to or greater than about 0.7. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a cyan print density equal to or greater than about 0.8. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a cyan print density equal to or greater than about 0.9.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a yellow print density equal to or greater than about 0.7. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a yellow print density equal to or greater than about 0.8. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a yellow print density equal to or greater than about 0.9.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a print index equal to or greater than about 400. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a print index equal to or greater than about 420. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a print index equal to or greater than about 440.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a line quality equal to or greater than about 0.8. In certain embodiments of any aspect of the present invention, ink printed on paper coated with the coating composition or ink printed on the coated paper has a line quality equal to or greater than about 0.85. In certain embodiments of any aspect of the present invention, ink printed on paper coated with the coating composition or ink printed on the coated paper has a line quality equal to or greater than about 0.9.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has an edge quality equal to or less than about 15. In certain embodiments of any aspect of the present invention, ink printed on paper coated with the coating composition or ink printed on the coated paper has an edge quality equal to or less than about 14. In certain embodiments of any aspect of the present invention, ink printed on paper coated with the coating composition or ink printed on the coated paper has an edge quality equal to or less than about 13.
  • ink printed on paper coated with the coating composition of the invention or ink printed on the coated paper of the invention has a smudge index after 15 seconds equal to or greater than about 9. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a smudge index after 15 seconds equal to or greater than about 9.5. In certain embodiments, ink printed on paper coated with the coating composition or ink printed on the coated paper has a smudge index after 15 seconds equal to about 10.
  • the ink is a pigment-based ink or a dye-based ink.
  • the coated paper is adapted to be used for printing with pigment-based inks and/or dye-based inks.
  • the coating composition has a Brookfield viscosity equal to or less than about 1500 mPa.s. In certain embodiments, the coating composition has a Brookfield viscosity equal to or less than about 1000 mPa.s. In certain embodiments, the coating composition has a Brookfield viscosity equal to or less than about 800 mPa.s.
  • the coating composition has a solids content of at least about 45 wt%. In certain embodiments, the coating composition has a solids content of at least about 50 wt%.
  • the coating composition has a solids content of at least about 45 wt% and a Brookfield viscosity equal to or less than about 1500 mPa.s.
  • compositions comprising a reduced amount of cationic polymer (e.g. zero cationic polymer);
  • compositions that provide paper that gives desired print properties e.g. ink jet print properties
  • desired print properties e.g. improved print properties
  • print density black, magenta, cyan, yellow
  • print index line and edge quality and smudge index
  • compositions that provide paper which has suitability for (e.g. improved suitability for) laser marking e.g. improved suitability for) laser marking
  • compositions that provide paper that is suitable for printing with dye-based and pigment-based inks • compositions that provide paper that is suitable for printing with dye-based and pigment-based inks
  • compositions with suitable viscosity for coating paper • compositions with suitable viscosity for coating paper.
  • coating compositions suitable for coating a fibrous substrate to make coated paper comprise a binder, an alkali earth metal compound (e.g calcium carbonate) and an anionic dispersant.
  • the coating compositions do not comprise a cationic polymer (i.e. comprise 0 wt% cationic polymer).
  • the coating compositions may, for example, consist essentially of or consist of a binder, an alkali earth metal compound (e.g. calcium carbonate) and an anionic dispersant.
  • the coating compositions may, for example, be advantageous in that they do not comprise a cationic polymer. This may, for example, enable the coating compositions to be made cheaply and easily.
  • the coating compositions may, for example, be advantageous in that they do not comprise cationic polymer but also provide a composition having a high solids content and a suitable viscosity for paper coating.
  • the coating compositions may, for example, be advantageous in that they do not comprise a cationic polymer but also provide paper having desirable print properties such as ink jet print properties (e.g. improved print properties or print properties that are approximately equal to the print properties of a paper coated with a composition comprising a greater amount of a cationic polymer).
  • the coating composition may, for example, be an aqueous suspension/dispersion.
  • the solids content of the coating composition may suitably be as high as possible whilst still giving a suitably fluid composition which may be used in coating a substrate (e.g. a fibrous substrate, e.g. paper).
  • the solids content and viscosity of the coating colour when applied to the paper may be significant. For example, if the solids content of the coating colour is too high, then the viscosity will be too high for easy metering and runnability problems may result, giving rise to so-called scratching and splashing. However, if the solids content is too low, the coating will flow too easily in the basepaper pores and poor coverage will result.
  • the coating does not penetrate into the pores, so it is held out onto the surface of the paper and is able to give a smooth surface.
  • the solids content of the coating composition may, for example, be at least about 45 wt%.
  • the solids content of the coating composition may be at least about 46 wt%, at least about 47 wt%, at least about 48 wt%, at least about 49 wt%, at least about 50 wt%, at least about 51 wt%, at least about 52 wt%, at least about 53 wt%, at least about 54 wt%, at least about 55 wt%.
  • the solids content of the coating composition may range from about 45 wt% to about 80 wt%, for example from about 45 wt% to about 75 wt%, for example from about 45 wt% to about 70 wt%, for example from about 45 wt% to about 65 wt%, for example from about 50 wt% to about 60 wt%.
  • the coating composition may be allowed to dry.
  • the coating may be in the form of a dry residue comprising a binder, an alkali earth metal compound, an anionic dispersant and optionally a cationic polymer.
  • the coating composition may, for example, have a Brookfield viscosity ranging from about 10 mPa.s to about 1500 mPa.s.
  • the coating composition may have a Brookfield viscosity equal to or less than about 1400 mPa.s, for example equal to or less than about 1300 mPa.s, for example equal to or less than about 1200 mPa.s, for example equal to or less than about 1 100 mPa.s, for example equal to or less than about 1000 mPa.s, for example equal to or less than about 900 mPa.s, for example equal to or less than about 800 mPa.s, for example equal to or less than about 700 mPa.s, for example equal to or less than about 600 mPa.s, for example equal to or less than about 500 mPa.s.
  • the coating composition may, for example, have a Brookfield viscosity equal to or greater than about 10 mPa.s, for example equal to or greater than about 50 mPa.s, for example equal to or greater than about 100 mPa.s, for example equal to or greater than about 150 mPa.s, for example equal to or greater than about 200 mPa.s.
  • Brookfield viscosity is measured at ambient temperature (22°C) using a Brookfield Viscometer set to operate at a spindle speed of 100 rpm.
  • the coating composition is thoroughly mixed using a Heidolph ST-1 laboratory stirrer. Immediately after mixing, the coating composition is transferred to the viscometer and the viscometer spindle is immersed in the composition. The viscometer spindle is activated 30 seconds after cessation of homogenisation and the Brookfield viscosity is recorded 15 seconds later.
  • Ink printed on paper coated with the coating composition may, for example, have a black print density equal to or greater than about 1.0.
  • ink printed on paper coated with the coating composition may have a black print density equal to or greater than about 1.05, for example equal to or greater than about 1.1 , for example equal to or greater than about 1 .15, for example equal to or greater than about 1 .2, for example equal to or greater than about 1.25, for example equal to or greater than about 1.3, for example equal to or greater than about 1.35, for example equal to or greater than about 1.4.
  • ink printed on paper coated with the coating composition may have a black print density up to about 2.0, for example up to about 1.9, for example up to about 1 .8, for example up to about 1.7, for example up to about 1.6, for example up to about 1 .5.
  • Ink printed on paper coated with the coating composition may, for example, have a magenta print density equal to or greater than about 0.7.
  • ink printed on paper coated with the coating composition may have a magenta print density equal to or greater than about 0.75, for example equal to or greater than about 0.8, for example equal to or greater than about 0.85, for example equal to or greater than about 0.9, for example equal to or greater than about 0.95, for example equal to or greater than about
  • ink printed on paper coated with the coating composition may have a magenta print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on paper coated with the coating composition may, for example, have a cyan print density equal to or greater than about 0.7.
  • ink printed on paper coated with the coating composition may have a cyan print density equal to or greater than about 0.75, for example equal to or greater than about 0.8, for example equal to or greater than about 0.85, for example equal to or greater than about 0.9, for example equal to or greater than about 0.95, for example equal to or greater than about 1.0, for example equal to or greater than about 1.05, for example equal to or greater than about 1.1 , for example equal to or greater than about 1.15, for example equal to or greater than about 1.2.
  • ink printed on paper coated with the coating composition may have a cyan print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on paper coated with the coating composition may, for example, have a yellow print density equal to or greater than about 0.7.
  • ink printed on paper coated with the coating composition may have a yellow print density equal to or greater than about 0.75, for example equal to or greater than about 0.8, for example equal to or greater than about 0.85, for example equal to or greater than about 0.9, for example equal to or greater than about 0.95, for example equal to or greater than about 1.0, for example equal to or greater than about 1.05, for example equal to or greater than about
  • ink printed on paper coated with the coating composition may have a yellow print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Print density is a ratio of incident light on a sample and reflected light back given by the formula:
  • Density Iogi 0 — h where lo is the intensity of the light source and IR is the intensity of reflected light. This is measured using a Gretag SpectroEye Densitometer. The print density values assist in obtaining a full estimate of the colour intensity of the print.
  • Ink printed on paper coated with the coating composition may, for example, have a print index equal to or greater than about 330.
  • ink printed on paper coated with the coating composition may have a print index equal to or greater than about 335, for example equal to or greater than about 340, for example equal to or greater than about 345, for example equal to or greater than about 350, for example equal to or greater than about 355, for example equal to or greater than about 360, for example equal to or greater than about 365, for example equal to or greater than about 370, for example equal to or greater than about 375, for example equal to or greater than about 380, for example equal to or greater than about 385, for example equal to or greater than about 390, for example equal to or greater than about 395, for example equal to or greater than about 400, for example equal to or greater than about 405, for example equal to or greater than about 410, for example equal to or greater than about 415, for example equal to or greater than about 420, for example equal to or greater than about 425, for example equal to or
  • Ink printed on paper coated with the coating composition may, for example, have a print index up to about 600, for example up to about 550, for example up to about 500.
  • ink printed on paper coated with the coating composition may have a print index up to about 490, for example up to about 480, for example up to about 460, for example up to about 470, for example up to about 460, for example up to about 450.
  • B n is the black print density of the sample
  • C n is the cyan print density of the sample etc.
  • B 0 is the black print density of ink printed on a control sample
  • Co is the cyan print density of ink printed on the control sample etc. Print density was measured as described above.
  • the control paper is a commercially available silica-coated paper.
  • Ink printed on paper coated with the coating composition may, for example, have a line quality equal to or greater than about 0.8.
  • ink printed on paper coated with the coating composition may have a line quality equal to or greater than about 0.85, for example equal to or greater than about 0.9.
  • Ink printed on paper coated with the coating composition may, for example, have a line quality up to about 1.0, for example up to about 0.99, for example up to about 0.98, for example up to about 0.97, for example up to about 0.96, for example up to about 0.95.
  • Line quality is determined by comparing the contrast between yellow and black areas and the evenness of a black band through a yellow background.
  • Image analysis is carried out by printing ink jet samples and scanning each ink jet printed sample using an Epson V500 photo scanner at 600 dpi and 24-bit colour and constant settings. All of the automatic corrections are turned off and the same histogram settings (0, 1.0, 255:0, 255) are used for all samples.
  • An image of 500x300 pixels is collected in the area where there is a black band running across a yellow background. The coloured image is then converted into a 256 greyscale image for use in the analysis.
  • a line profile is taken through the black band. For acceptable or good quality prints, the profile is relatively smooth (low mottle) and angular with steep sides and a flat bottom.
  • the difference between the black and yellow intensity is a measure of the print contrast, wherein the black intensity is the average of all the minimum black points from the profiles taken from the greyscale images and the yellow intensity is the average of the yellow background from the profiles taken from the RGB colour images.
  • the line quality is equal to the width at 25% between the yellow intensity and the black intensity divided by the width at 75% between the yellow intensity and the black intensity. Similar width values are better, so a perfect line would have a line quality of 1. This metric gives an indication of the amount of ink spread and the degree of mottle or unevenness occurring in connection with the printed black bar.
  • Ink printed on paper coated with the coating composition may, for example, have an edge quality equal to or less than about 15.
  • ink printed on paper coated with the coating composition may have an edge quality equal to or less than about 14, for example equal to or less than about 13, for example equal to or less than about 12.
  • Ink printed on paper coated with the coating composition may, for example, have an edge quality equal to or more than about 0, for example equal to or more than about 1 , for example equal to or more than about 2, for example equal to or more than about 3, for example equal to or more than about 4, for example equal to or more than about 5.
  • Edge quality is measured by obtaining a pixel view of a thresholded black/yellow interface and counting the number of white pixels next to each interface black pixel.
  • Edge quality is the % of interface black pixels with 2 or 3 adjacent white pixels. A lower number indicates better edge quality.
  • Ink printed on paper coated with the coating composition may, for example, have a smudge index after 15 seconds equal to or greater than about 9.
  • ink printed on paper coated with the coating composition may have a smudge index after 15 seconds equal to or greater than about 9.5, for example equal to or less than about 10.
  • ink printed on paper coated with the coating composition may have a smudge index after 15 seconds equal to about 10.
  • Smudge index is measured by printing a test print using a desktop printer and commercial pigment-based ink jet inks.
  • the test contains areas of 00% black ink, printed as approx 1 cm 2 blocks. Fifteen seconds after the print has been made, a finger from a skilled operator, covered with a rubber glove is contacted with the black printed square and then pulled downwards applying a constant firm pressure. Any non- dried/non-immobilized ink will be dragged onto the unprinted portion of the paper. The degree of ink transfer to the paper is assessed visually and given a ranking out of 10, where 10 indicates no transfer of ink - i.e. the print is dried. A score of around 5 or 6 shows considerable transfer of ink. The test gives a reasonable comparison between different papers when printed using the same printer and the same ink. Binder
  • binder capable of providing a coating composition having any one or more of the advantageous properties described herein may suitably be used.
  • suitable materials for use as binders and/or cobinding agents are generally known in the art.
  • suitable materials include latex, starch, starch derivatives, sodium carboxymethyl cellulose, polyvinyl alcohol, proteins and combinations thereof.
  • the binder may or may not be a blend and may or may not consist essentially of or consist of polyvinyl alcohol or starch.
  • the binder may, for example, be a cationic binder.
  • the binder may, for example, be starch or a starch derivative.
  • the binder may, for example, be a cationic starch.
  • a starch binder may, for example, be derived from natural starch obtained from a known plant source.
  • Other binders that may be used include, for example, adhesives derived from natural starch obtained from a known plant source, for example, wheat, maize, potato or tapioca.
  • exemplary binders include, for example, latex binders.
  • latex is used herein to mean a dispersion/suspension (e.g. aqueous dispersion/suspension) of one or more polymer(s).
  • Commercially available latex products are typically sold as aqueous emulsions containing 50 wt% latex. These products are suitable for use in the present compositions.
  • the polymers may, for example, be natural or synthetic.
  • the latex binder may, for example, be natural rubber latex obtained from, for example, rubber trees.
  • the latex binder may, for example, be a synthetic latex.
  • the latex binder may, for example, be a styrene polymer, for example copolymers including styrene monomers.
  • the latex binder may be a copolymer comprising, consisting essentially of or consisting of alkene monomers (e.g. ethylene, propylene, butylene, butadiene) and styrene monomers.
  • the latex binder may be styrene butadiene.
  • the latex binder may, for example, be polyurethane, polyester and/or polyethyleneacrylate dispersions.
  • the latex binder may, for example, be an acrylic-based latex or an acetate- based latex (e.g.
  • polyvinyl acetate, vinyl acetate latex or styrene acrylic or acrylic latex may, for example, be casein.
  • the binder may, for example, be an alcohol- based binder, such as polyvinyl alcohol.
  • Blends comprising or consisting of polyvinyl alcohol and latex may be particularly advantageous in providing a good balance of properties.
  • Polyvinyl alcohol may assist in lowering the viscosity of the coating composition and the latex may assist in lowering the set off tendency of the printed ink.
  • Polyvinyl alcohol may be obtained by conventional methods known in the art, such as, for example by partial or complete hydrolysis of polyvinyl acetate to remove acetate groups.
  • polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate may contain pendant acetate groups as well as pendant hydroxy groups.
  • the polyvinyl alcohol is derived from partially or fully hydrolysed polyvinyl acetate.
  • the extent of hydrolysis may be such that at least about 50 mole % of the acetate groups are hydrolysed, for example, at least about 60 mole % of the acetate groups are hydrolysed, for example, at least about 70 mole % of the acetate groups are hydrolysed, for example, at least about 80 mole % of the acetate groups are hydrolysed, for example, at least about 85 mole % of the acetate groups are hydrolysed, for example, at least about 90 mole % of the acetate groups are hydrolysed, for example, at least about 95 mole % of the acetate groups are hydrolysed or, for example, at least about 99 mole % of the acetate groups are hydrolysed.
  • the polymer may, for example, be a copolymer of polyvinyl alcohol and other monomers, such as, for example, acetate and acrylate.
  • the amount of binder in the coating composition will depend on the binder used and the desired end product.
  • the coating composition may comprise any amount of binder suitable to allow the surfaces of paper, when coated with the coating composition, to receive ink without disruption.
  • the coating composition may comprise from about 1 pph to about 50 pph, for example from about 1 pph to about 40 pph, for example from about 1 pph to about 35 pph, for example from about 1 pph to about 30 pph, for example from about 1 pph to about 25 pph, for example from about 1 pph to about 20 pph binder.
  • 12 pph binder is 12 g of dry binder in 100 g of dry inorganic particulate material).
  • the coating composition may comprise from about 3 pph or from about 5 pph or from about 8 pph to about 50 pph or to about 40 pph or to about 35 pph or to about 30 pph or to about 25 pph or to about 20 pph binder based on the total dry inorganic particulate material in the composition.
  • the coating composition may comprise from about 5 pph to about 50 pph, for example from about 5 pph to about 40 pph, for example from about 5 pph to about 35 pph, for example from about 5 pph to about 30 pph, for example from about 5 pph to about 25 pph, for example from about 5 pph to about 20 pph binder based on the total dry inorganic particulate material in the composition.
  • the coating compositions provided herein comprise an alkali earth metal compound.
  • the alkali earth metal compound may, for example, be any alkali earth metal salt, for example any alkali earth metal acetate, carbonate, citrate, cyanide, sulphate, halide (e.g. chloride, fluoride), nitrate, nitrite, phosphate, hydroxide.
  • the alkali earth metal compound may, for example, be an alkali earth metal carbonate.
  • the alkali earth metal compound may, for example be any calcium salt.
  • the present invention may tend to be discussed in terms of calcium carbonate. However, the invention should not be construed as being limited as such.
  • the coating compositions provided herein may, for example, comprise calcium carbonate.
  • Examples of calcium carbonate include ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), dolomite and surface-modified calcium carbonate.
  • the particulate calcium carbonate used in embodiments of the present invention may be obtained from a natural source by grinding or may be prepared synthetically by precipitation (PCC), or may be a combination of the two, i.e. a mixture of the naturally derived ground material and the synthetic precipitated material.
  • the PCC may also be ground.
  • the inorganic particulate material used in embodiments of the present invention When the inorganic particulate material used in embodiments of the present invention is obtained from naturally occurring sources, it may be that some mineral impurities will inevitably contaminate the ground material. For example, naturally occurring calcium carbonate occurs in association with other minerals. In general, however, the inorganic particulate material used in embodiments of the present invention will contain less than 5% by weight, preferably less than 1 % by weight of other mineral impurities.
  • Ground calcium carbonate (GCC) is typically obtained by grinding a mineral source such as chalk, marble or limestone, which may be followed by a particle size classification step, in order to obtain a product having the desired degree of fineness.
  • the particulate solid material may be ground autogenously, i.e. by attrition between the particles of the solid material themselves, or alternatively, in the presence of a particulate grinding medium comprising particles of a different material from the calcium carbonate to be ground.
  • Wet grinding of calcium carbonate involves the formation of an aqueous suspension of the calcium carbonate which may then be ground, optionally in the presence of a suitable dispersing agent.
  • a suitable dispersing agent for example, EP-A-614948 (the contents of which are incorporated by reference in their entirety) for more information regarding the wet grinding of calcium carbonate.
  • PCC may be used as the source of particulate calcium carbonate in embodiments of the present invention, and may be produced by any of the known methods available in the art.
  • TAPPI Monograph Series No 30, "Paper Coating Pigments", pages 34-35 describes the three main commercial processes for preparing precipitated calcium carbonate which is suitable for use in preparing products for use in the paper industry, but may also be used in connection with the embodiments of the present invention. In all three processes, limestone is first calcined to produce quicklime, and the quicklime is then slaked in water to yield calcium hydroxide or milk of lime. In the first process, the milk of lime is directly carbonated with carbon dioxide gas.
  • the milk of lime is contacted with soda ash to produce, by double decomposition, a precipitate of calcium carbonate and a solution of sodium hydroxide.
  • the sodium hydroxide should be substantially completely separated from the calcium carbonate if this process is to be commercially attractive.
  • the milk of lime is first contacted with ammonium chloride to give a calcium chloride solution and ammonia gas.
  • the calcium chloride solution is then contacted with soda ash to produce, by double decomposition, precipitated calcium carbonate and a solution of sodium chloride.
  • the process for making PCC results in very pure calcium carbonate crystals and water.
  • the crystals can be produced in a variety of different shapes and sizes, depending on the specific reaction process that is used.
  • the three main forms of PCC crystals are aragonite, rhombohedral and scalenohedral, all of which are suitable for use in embodiments of the present invention, including mixtures thereof.
  • the PCC used in the present invention may, for example, be in scalenohedral form.
  • PCC precipitated calcium carbonate
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, have a dso equal to or greater than about 0.4 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may have a dso equal to or greater than about 0.45 ⁇ , for example equal to or greater than about 0.5 ⁇ , for example equal to or greater than about 0.55 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may have a dso equal to or greater than about 0.6 pm.
  • the alkali earth metal compound such as calcium carbonate may have a dso equal to or greater than about 0.65 pm, for example equal to or greater than about 0.7 pm, for example equal to or greater than about 0.75 pm, for example equal to or greater than about 0.8 pm.
  • the alkali earth metal compound such as calcium carbonate e.g. PCC
  • the alkali earth metal compound such as calcium carbonate e.g.
  • PCC may, for example have a dso up to about 1.5 pm, for example up to about 1.45 pm, for example up to about 1.4 pm, for example up to about 1.35 pm, for example up to about 1 .3 pm, for example up to about 1.25 pm, for example up to about 1.2 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may have a d 5 o of about 1.1 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise at least about 65 wt% of particles smaller than 2 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may comprise at least about 70 wt%, for example at least about 72 wt% of particles smaller than 2 ⁇ .
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise up to about 80 wt% of particles smaller than 2 pm, for example up to about 75 wt% of particles smaller than 2 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise at least about 35 wt% of particles smaller than 1 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may comprise at least about 40 wt%, for example at least about 42 wt% of particles smaller than 1 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise up to about 50 wt% of particles smaller than 1 pm, for example up to about 48 wt%, for example up to about 45 wt% of particles smaller than 1 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise at least about 5 wt% of particles smaller than 0.5 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may comprise at least about 10 wt%, for example at least about 12 wt% of particles smaller than 0.5 pm.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, comprise up to about 20 wt% of particles smaller than 0.5 pm, for example up to about 15 wt%, for example up to about 12 wt% of particles smaller than 0.5 pm.
  • the mean (average) equivalent particle diameter (dso value) and other particle size properties referred to herein for the inorganic particulate materials are as measured in a well known manner by sedimentation of the particulate material in a fully dispersed condition in an aqueous medium using a Sedigraph 5100 machine as supplied by Micromeritics Instruments Corporation, Norcross, Georgia, USA (telephone: +1 770 662 3620; web-site: www.micromeritics.com), referred to herein as a "Micromeritics Sedigraph 5100 unit".
  • Such a machine provides measurements and a plot of the cumulative percentage by weight of particles having a size, referred to in the art as the 'equivalent spherical diameter' (esd), less than given esd values.
  • the mean particle size dso is the value determined in this way of the particle esd at which there are 50% by weight of the particles which have an equivalent spherical diameter less than that dso value.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example have a BET specific surface area less than about 40 m 2 /g.
  • the alkali earth metal compound such as calcium carbonate e.g.
  • PCC may have a BET specific surface area equal to or less than about 35 m 2 /g, for example equal to or less than about 30 m 2 /g, for example equal to or less than about 25 m 2 /g, for example equal to or less than about 20 m 2 /g, for example equal to or less than about 15 m 2 /g, for example equal to or less than about 10 m /g.
  • the alkali earth metal compound such as calcium carbonate (e.g. PCC) may, for example, have a BET specific surface area equal to or greater than about 1 m 2 /g, for example equal to or greater than about 5 m 2 /g.
  • the alkali earth metal compound such as calcium carbonate may, for example, be present in the coating composition in an amount ranging from about 50 wt% to about 98 wt% based on the total dry weight of the composition.
  • the calcium carbonate may be present in the coating composition in an amount ranging from about 55 wt% to about 95 wt%, for example from about 60 wt% to about 90 wt%, for example from about 65 wt% to about 85 wt%, for example from about 70 wt% to about 80 wt% based on the total dry weight of the composition.
  • anionic dispersant suitable for dispersing fine particle solids may be used.
  • the anionic dispersant may, for example, comprise, consist essentially of or consist of neutralized salts of polymers or copolymers (e.g. alkali metal salts and ammonium salts).
  • the salts may, for example, comprise an alkali metal salt (e.g. sodium salt) or an ammonium salt.
  • the anionic dispersant may, for example, be one or more polycarboxylates (i.e. a polymer having at least one monomer containing a carboxylate group), such as a vinyl or olefinic group substituted with at least one carboxylic acid group or a water soluble salt.
  • the polycarboxylate may also comprise non-carboxylate containing monomers.
  • Exemplary monomers for a polycarboxylate anionic dispersant include, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, isocrotonic acid, aconitic acid, mesaconic acid, sinapinic acid, undecylenic acid, angelic acid, hydroxacrylic acid, and vinyl acetate.
  • Copolymers may include monomers containing a vinyl or olefinic group such as styrene.
  • the polycarboxylate may, for example, be partially or wholly neutralized salts of the polymer or copolymer.
  • the anionic dispersant may, for example, be a polyacrylate and/or a salt of polyacrylate (e.g. sodium polyacrylate) or a maleic anhydride copolymer and/or a salt of a maleic anhydride copolymer.
  • the anionic dispersant may, for example, be a homopolymer and/or a copolymer of acrylic acid and/or methacrylic acid and/or maleic acid and/or maleic anhydride.
  • the anionic dispersant may be a water soluble homopolymer or copolymer of acrylic acid and/or methacrylic acid and/or maleic acid (e.g. a maleic acrylic copolymer).
  • the anionic dispersant may comprise, consist essentially of or consist of a homopolymer of acrylic acid.
  • the anionic dispersant may, for example, be partially or wholly neutralized salts of the polymer or copolymer.
  • the polymer or copolymer may have a molar ratio of acrylic acid units to maleic acid units ranging from 0.5: 1 to 10: 1.
  • the polymer or copolymer e.g. maleic acrylic copolymer
  • any combination of the exemplary anionic dispersants described herein may also be used.
  • the invention may tend to be discussed in terms of polyacrylates, in particular homopolymers of acrylic acid. However, the invention should not be construed as being limited as such.
  • the anionic dispersant may, for example, be present in the coating composition in an amount ranging from about 0.1 pph to about 5 pph. This is the dry weight of the anionic dispersant based on the dry weight of the total inorganic particulate material in the coating (e.g. 2 pph anionic dispersant is 2 g of dry anionic dispersant in 100 g of dry inorganic particulate material).
  • the anionic dispersant may be present in the coating composition in an amount ranging from about 0.1 pph to about 4 pph, for example from about 0.1 pph to about 3 pph, for example from about 0.1 pph to about 2 pph, for example from about 0.1 pph to about 1 pph based on the total dry inorganic particulate material in the composition.
  • the anionic dispersant may be present in the coating composition in an amount ranging from about 0.5 pph to about 5 pph, for example from about 1 pph to about 5 pph, for example from about 1 pph to about 4 pph, for example from about 1 pph to about 3 pph, for example from about 1 pph to about 2 pph based on the total dry inorganic particulate material in the composition.
  • the term cationic polymer may, for example, encompass polymers possessing a net positive charge.
  • the cationic polymer may, for example, be a cationic dispersant.
  • the coating compositions provided herein may not comprise a cationic dispersant.
  • the cationic polymer may, for example, be a synthetic cationic polymer, thus the coating compositions provided herein may not comprise a synthetic cationic dispersant.
  • the cationic polymer may, for example, be a polymeric amine, such as a polymer of quaternary amines, or a polymer of amines that can be converted to quaternary amines, and combinations thereof.
  • the cationic polymer may contain two or more different cationic monomers, or contain a cationic monomer and other non-ionic or anionic monomers.
  • Suitable monomers in the cationic polymer may include one or more monomers selected from water soluble polyolefins containing quaternary ammonium groups which may be in the polymer chain, for example, epichlorohydrin/dimethylamine copolymers (EPI/D A), alkyl-or dialkyldiallylammonium halides, such as dimethyidiallylammonium chloride (DMDAAC), diethyldiallyl ammonium chloride (DEDAC), dimethyldiallyl ammonium bromide (DMDAAB) and diethyldiallyl ammonium bromide (DEDAAB), methylacryloyl-oxyethyltrimethyl ammonium chloride (METAC), acryloy-oxyethyltrimethyl ammonium chloride (AETAC), methacryloyloxy
  • exemplary monomers include dimethylaminoethylacrylate, dimethylaminoethylmethacrylate, dimethylamino propylmethacrylamide and its methyl chloride or dimethyl sulfate quaternary ammonium salts, dimethylaminoethylacrylate and its methyl chloride salt, methacrylamidopropyltrimethylammonium chloride and its unquaternized amine form, acrylamidopropyltrimethylammonium chloride and its unquaternized amine form, and dimethylamine and epichlorohydrin.
  • Exemplary polymers may also include products of copolymerizing epichlorohydrin and amines, especially secondary amines, alone or in combination, and polymers made by polymerizing any of the above listed cationic monomers with non-ionic monomers such as acrylamide, methacrylamide or N, N- dimethylacrylamide.
  • Exemplary cationic polymers may include polydiallyldimethylammonium chloride (pDADMAC), copolymers of quaternary dimethylaminoethyl acrylate, and copolymers of quaternary dimethylaminoethyl methacrylate, and copolymers of epichlorohydrin/dimethylamine (EPI/DMA).
  • pDADMAC polydiallyldimethylammonium chloride
  • EPI/DMA epichlorohydrin/dimethylamine
  • Exemplary suitable polymers are commercially available as AgeflocB-50LV®, Nalco62060®, Nalco7135, Nalco 7132®, and Nalco 8850®.
  • exemplary cationic polymers may include condensates of formaldehyde with melamine, urea, or cyanoguanidine.
  • the cationic polymers may also include copolymers of the aforementioned cationic monomers with nonionic monomers, such as acrylamide, methacrylamide, vinyl acetate, vinyl alcohol, N-methylolacrylamide, or diacetone acrylamide, and/or anionic monomers, such as acrylic acid, methacrylic acid, AMPS, or maleic acid, such that the net charge of these polymers is cationic.
  • the cationic polymer may have a weight average molecular weight ranging from about 1 ,000 daltons to about 5,000, 000 daltons, as determined by gel permeation chromatography.
  • the cationic polymer may have a molecular weight of at least about 1 ,000, such as molecular weights of at least about 2,000, at least about 5,000. at least about 10,000, at least about 25,000, at least about 50,000, at least about 100,000, at least about 250,000, at least about 500,000 or at least about 1 ,000, 000.
  • Physical blends of cationic polymers containing different cationic moieties or blends of cationic polymers possessing different molecular weight averages and distributions may also be used.
  • the bulk viscosity of the at least one cationic polymer may also reflect its weight average molecular weight.
  • the cationic polymer may have a bulk viscosity of at least about 300 cps, such as a bulk viscosity of at least about 400 cps.
  • the cationic polymer may have a bulk viscosity ranging from about 300 cps to about 10,000 cps.
  • the cationic polymer has a bulk viscosity of at least about 2,000, such as a bulk viscosity of at least about 3,000 cps, such as a bulk viscosity of at least about 4,000 cps, or bulk viscosities ranging from about 4,000 cps to about 10,000, or from about 4,000 cps to about 6,000 cps.
  • the cationic polymer may, for example, be present in the coating composition in an amount less than about 2 wt% relative to the total weight of inorganic particulate material in the composition or relative to the total weight of alkali earth metal compound such as calcium carbonate in the composition.
  • the cationic polymer may be present in the coating composition in an amount less than about 1.5 wt%, for example less than about 1 wt%, for example less than about 0.5 wt%, for example less than about 0.1 wt%, for example less than about 0.05 wt% relative to the total weight of inorganic particulate material in the composition or relative to the total weight of alkali earth metal compound such as calcium carbonate in the composition.
  • the cationic polymer may, for example, not be present in the coating composition (i.e. present in the coating composition in an amount of 0 wt%).
  • the coating composition may comprise from 0 wt% to about 2 wt% cationic polymer.
  • the coating composition may comprise from about 0.05 wt% or from about 0.1 wt% or from about 0.5 wt% or from about 1 wt% to about 2 wt% cationic polymer relative to the total weight of inorganic particulate material in the coating composition or relative to the total weight of alkali earth metal compound such as calcium carbonate in the composition.
  • the coating composition may, for example, comprise one or more additional inorganic particulate materials.
  • the coating composition may consist essentially of or consist of a binder, an alkali earth metal compound, an anionic dispersant and an additional inorganic particulate material (e.g. an aluminosilicate).
  • an additional inorganic particulate material e.g. an aluminosilicate such as kaolin, for example hydrous kaolin
  • an additional inorganic particulate material e.g. an aluminosilicate such as kaolin, for example hydrous kaolin
  • the additional inorganic particulate material may, for example, be selected from an alkaline earth metal compound (e.g. alkali earth metal carbonate or sulphate (e.g. magnesium carbonate, dolomite and gypsum)); a phyllosilicate, an aiuminosilicate (e.g. hydrous kandite clay including kaolin, halloysite clay, ball clay, anhydrous (calcined) kandite clay such as metakaolin, fully calcined kaolin and mica); talc, chlorite, pyrophyllite, serpentine, perlite, diatomaceous earth, magnesium hydroxide, aluminium trihydrate and combinations thereof.
  • an alkaline earth metal compound e.g. alkali earth metal carbonate or sulphate (e.g. magnesium carbonate, dolomite and gypsum)
  • a phyllosilicate e.g. hydrous kandite clay including kaolin, halloysite clay, ball clay,
  • the additional inorganic particulate material may, for example, be an aiuminosilicate, for example, kaolin.
  • the coating composition may further comprise hydrous kaolin or partially calcined kaolin or fully calcined kaolin.
  • the aiuminosilicate may be an anhydrous kaolin clay having at least about 65 wt% of particles smaller than 2 pm, for example at least about 75 wt% of particles smaller than 2 pm, for example at least about 85 wt% of particles smaller than 2 pm, for example at least about 90 wt% of particles smaller than 2 pm.
  • the anhydrous kaolin clay may, for example, have a dso ranging from about 0.4 pm to about 0.8 pm, for example from about 0.5 pm to about 0.7 pm, for example about 0.65 pm.
  • the anhydrous kaolin clay may, for example, have a surface area up to about 20 m 2 /g, for example up to about 15 m 2 /g, for example ranging from about 10 m 2 /g to about 15 m 2 /g.
  • the aiuminosilicate may be a hydrous clay having at least about 65 wt% of particles smaller than 2 pm, for example at least about 75 wt% of particles smaller than 2 pm, for example at least about 85 wt% of particles smaller than 2 pm, for example at least about 90 wt% of particles smaller than 2 pm.
  • the hydrous aiuminosilicate may, for example, have a least about 50 wt% of particles smaller than 1 pm, for example at least about 60 wt% of particles smaller than 1 pm, for example at least about 65 wt% of particles smaller than 1 pm, for example at least about 70 wt% of particles smaller than 1 pm.
  • the hydrous aiuminosilicate may, for example, have at least about 30 wt% of particles smaller than 0.5 pm, for example at least about 35 wt% of particles smaller than 0.5 pm, for example at least about 40 wt% of particles smaller than 0.5 pm, for example at least about 45 wt% of particles smaller than 1 pm.
  • the hydrous aiuminosilicate may, for example, have a dso ranging from about 0.4 pm to about 0.7 pm, for example from about 0.5 pm to about 0.6 pm.
  • the hydrous aiuminosilicate may, for example, have at least about 90 wt% of particles smaller than 2 pm, at least about 70 wt% of particles smaller than 1 pm and at least about 45 w ⁇ % of particles smaller than 0.5 pm.
  • the hydrous aluminosilicate may, for example, have a surface area up to about 20 m 2 /g, for example up to about 15 m 2 /g, for example ranging from about 10 m 2 /g to about 15 m 2 /g.
  • the weight ratio of alkali earth metal compound (e.g. calcium carbonate) to additional inorganic particulate materia! (e.g. aluminosilicate) may range from about 60:40 to about 95:5.
  • the weight ratio of alkali earth metal compound (e.g. calcium carbonate) to additional inorganic particulate material (e.g. aluminosilicate) may range from about 65:35 to about 90: 10, for example from about 70:30 to about 85:15, for example from about 75:25 to about 85: 15.
  • the weight ratio of alkali earth metal compound (e.g. calcium carbonate) to additional inorganic particulate material (e.g. aluminosilicate) may be about 85: 15.
  • the additional inorganic particulate material may, for example, be present in the coating composition in an amount ranging from about 0 pph to about 30 pph. This is the dry weight of the additional inorganic particulate material based on the dry weight of the total inorganic particulate material in the coating composition (e.g. 12 pph kaolin is 12 g of kaolin in 100 g of total dry inorganic particulate material). For example, if the total weight of inorganic particulate material in the composition is 100 g, 15 g (15 pph) may be kaolin and 85 g (85 pph) may be alkali earth metal compound.
  • the additional inorganic particulate material e.g.
  • aluminosilicate may, for example, be present in the coating composition in an amount ranging from about 2 pph to about 25 pph, for example from about 5 pph to about 20 pph, for example from about 10 pph to about 15 pph, for example about 15 pph based on the total dry inorganic particulate material in the composition.
  • the additional inorganic particulate material may, for example, be used in an amount that enables acceptable or good laser marking of a coated paper.
  • the coating compositions may, for example, include one or more optional additives, if desired.
  • the coating compositions may include one or more of the optional additives listed below.
  • the coating composition may consist essentially of or consist of a binder, a calcium carbonate, an anionic dispersant, optionally an additional inorganic particulate material, optionally a cationic polymer and optionally one or more of the additives listed below.
  • the coating composition may consist essentially of or consist of a binder, a calcium carbonate, an anionic dispersant, optionally an additional inorganic particulate material and optionally one or more of the additives listed below.
  • the coating composition may consist essentially of or consist of a binder, a calcium carbonate, an anionic dispersant and optionally one or more of the additives listed below.
  • Such optional additives may suitably be selected from known additives for coating compositions (e.g. paper coating compositions). Some of these optional additives may provide more than one function in the coating composition. Examples of known classes of optional additives are as follows:
  • cross-linkers e.g. glyoxals, melamine formaldehyde resins, ammonium zirconium carbonates
  • one or more water retention aids e.g. sodium carboxymethyl cellulose, hydroxyethyl cellulose, PVA (polyvinyl acetate), starches, proteins, polyacrylates, gums, alginates, polyacrylamide bentonite and other commercially available products sold for such applications;
  • water retention aids e.g. sodium carboxymethyl cellulose, hydroxyethyl cellulose, PVA (polyvinyl acetate), starches, proteins, polyacrylates, gums, alginates, polyacrylamide bentonite and other commercially available products sold for such applications
  • viscosity modifiers or thickeners e.g. polyacrylates, emulsion copolymers, dicyanamide, triols, polyoxyethylene ether, urea, sulphated castor oil, polyvinyl pyrrolidone, montmorillonite, CMC (carboxymethyl celluloses), sodium alginate, xanthan gum, sodium silicate, acrylic acid copolymers, HMC (hydroxymethyl celluloses, HEC (hydroxyethyl celluloses));
  • viscosity modifiers or thickeners e.g. polyacrylates, emulsion copolymers, dicyanamide, triols, polyoxyethylene ether, urea, sulphated castor oil, polyvinyl pyrrolidone, montmorillonite, CMC (carboxymethyl celluloses), sodium alginate, xanthan gum, sodium silicate, acrylic acid copolymers, HMC (hydroxymethyl celluloses, HEC (hydroxyethyl celluloses));
  • one or more lubricity or calendering aids e.g. calcium stearate, ammonium stearate, zinc stearate, wax emulsions, waxes, alkyl ketene dimer, glycols;
  • one or more additional dispersants e.g. polyelectrolytes such as polyacrylates and copolymers containing polyacrylate species, polyacrylate salts, sodium hexametaphosphates, non-ionic polyol, polyphosphoric acid, condensed sodium phosphate, non-ionic surfactants, alkanolamine and other reagents commonly used for this function;
  • additional dispersants e.g. polyelectrolytes such as polyacrylates and copolymers containing polyacrylate species, polyacrylate salts, sodium hexametaphosphates, non-ionic polyol, polyphosphoric acid, condensed sodium phosphate, non-ionic surfactants, alkanolamine and other reagents commonly used for this function
  • additional dispersants e.g. polyelectrolytes such as polyacrylates and copolymers containing polyacrylate species, polyacrylate salts, sodium hexametaphosphates, non-ionic polyol, poly
  • one or more antifoamers or defoamers e.g. blends of surfactants, tributyl phosphate, fatty polyoxyethylene esters plus fatty acid alcohols, fatty acid soaps, silicone emulsions, silicone-containing compositions, waxes and inorganic particulates in mineral oil, blends of emulsified hydrocarbons and other compounds sold commercially to carry out this function;
  • one or more dry or wet pick improvement additives e.g. melamine resin, polyethylene emulsions, urea formaldehyde, melamine formaldehyde, polyamide, calcium stearate, styrene maleic anhydride and other compounds sold commercially for this function;
  • dry or wet pick improvement additives e.g. melamine resin, polyethylene emulsions, urea formaldehyde, melamine formaldehyde, polyamide, calcium stearate, styrene maleic anhydride and other compounds sold commercially for this function
  • dry or wet rub improvement and abrasion resistance additives e.g. glyoxal based resins, oxidized polyethylenes, melamine resins, urea formaldehyde, melamine formaldehyde, polyethylene wax, calcium stearate and other compounds sold commercially for this function;
  • one or more gloss-ink hold-out additives e.g. oxidized polyethylenes, polyethylene emulsions, waxes, casein, guar gum, CMC, HMC, calcium stearate, ammonium stearate, sodium alginate and other compounds sold commercially for this function;
  • OSA optical brightening agents
  • FWA fluorescent whitening agents
  • biocides or spoilage control agents e.g. metaborate, sodium dodecylbenene sulphonate, thiocyanate, organosulphur, sodium benzonate and other compounds sold commercially for this function
  • biocides or spoilage control agents e.g. metaborate, sodium dodecylbenene sulphonate, thiocyanate, organosulphur, sodium benzonate and other compounds sold commercially for this function
  • one or more levelling or evening aids e.g. non-ionic polyol, polyethylene emulsions, fatty acid esters and alcohol derivatives, alcohol/ethylene oxide, sodium CMC, HEC, alginates, calcium stearate and other compounds sold commercially for this function;
  • levelling or evening aids e.g. non-ionic polyol, polyethylene emulsions, fatty acid esters and alcohol derivatives, alcohol/ethylene oxide, sodium CMC, HEC, alginates, calcium stearate and other compounds sold commercially for this function
  • one or more grease or oil resistance agents e.g. oxidized polyethylenes, latex, SMA (styrene maleic anhydride), polyamide, waxes, alginate, protein, CMC, HMC
  • one or more water resistance additives e.g. oxidized polyethylenes, ketone resin, anionic latex, polyurethane, SMA, glyoxal, melamine resin, urea formaldehyde, melamine formaldehyde, polyamide, glyoxals, stea rates and other compounds sold commercially for this function
  • grease or oil resistance agents e.g. oxidized polyethylenes, latex, SMA (styrene maleic anhydride), polyamide, waxes, alginate, protein, CMC, HMC
  • water resistance additives e.g. oxidized polyethylenes, ketone resin, anionic latex, polyurethane, SMA, glyoxal, melamine resin, urea formalde
  • any of the above additives and additive types may be used alone or in admixture with each other and with other additives, if desired.
  • the percentages by weight (based on the total solids content (100%) of the composition) can vary as understood by those skilled in the art.
  • the minimum amount may be about 0.01 % by weight based on the total solids content of the composition.
  • the maximum amount of any one or more of the above additives may, for example, be about 5.0% by weight based on the total solids content of the composition.
  • the maximum amount may be about 3.0% or 2.0% by weight based on the total solids content of the composition.
  • the coating composition may, for example, comprise a starch binder (e.g. a cationic starch binder) and a precipitated calcium carbonate.
  • the coating composition may comprise a starch binder (e.g. a cationic starch binder), a precipitated calcium carbonate and an anionic dispersant that is a homopolymer or copolymer of (meth)acrylic acid.
  • the coating composition may comprise a starch binder (e.g. a cationic starch binder), a precipitated calcium carbonate, an anionic dispersnt that is a homopolymer or copolymer of (meth)acrylic acid and an aluminosilicate (e.g. kaolin).
  • coated paper may, for example, comprise a fibrous substrate coated with a coating composition.
  • the coating composition may, for example, be in accordance with any aspect or embodiment described herein, including all possible combinations and variations thereof.
  • Ink printed on the coated paper may, for example, have a black print density equal to or greater than about 1.0.
  • ink printed on the coated paper may have a black print density equal to or greater than about 1.1 , for example equal to or greater than about 1.2, for example equal to or greater than about 1.3, for example equal to or greater than about 1.4.
  • Ink printed on the coated paper may, for example, have a black print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on the coated paper may, for example, have a magenta print density equal to or greater than about 0.7.
  • ink printed on the coated paper may have a magenta print density equal to or greater than about 0.8, for example equal to or greater than about 0.9, for example equal to or greater than about 1.0, for example equal to or greater than about 1.1 , for example equal to or greater than about 1.2.
  • Ink printed on the coated paper may, for example, have a magenta print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on the coated paper may, for example, have a cyan print density equal to or greater than about 0.7.
  • ink printed on the coated may have a cyan print density equal to or greater than about 0.8, for example equal to or greater than about 0.9, for example equal to or greater than about 1.0, for example equal to or greater than about 1.1 , for example equal to or greater than about 1.2.
  • Ink printed on the coated paper may, for example, have a cyan print density up to about 2.0, for example up to about 1.9, for example up to about 1 .8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on the coated paper may, for example, have a yellow print density equal to or greater than about 0.7.
  • ink printed on the coated paper may have a yellow print density factor equal to or greater than about 0.8, for example equal to or greater than about 0.9, for example equal to or greater than about 1.0, for example equal to or greater than about 1.1 , for example equal to or greater than about 1.2.
  • Ink printed on the coated paper may, for example, have a yellow print density up to about 2.0, for example up to about 1.9, for example up to about 1.8, for example up to about 1.7, for example up to about 1.6, for example up to about 1.5.
  • Ink printed on the coated paper may, for example, have a print index equal to or greater than about 330.
  • ink printed on the coated paper may have a print index equal to or greater than about 335, for example equal to or greater than about 340, for example equal to or greater than about 345, for example equal to or greater than about 350, for example equal to or greater than about 355, for example equal to or greater than about 360, for example equal to or greater than about 365, for example equal to or greater than about 370, for example equal to or greater than about 375, for example equal to or greater than about 380, for example equal to or greater than about 385, for example equal to or greater than about 390, for example equal to or greater than about 395, for example equal to or greater than about 400, for example equal to or greater than about 405, for example equal to or greater than about 410, for example equal to or greater than about 415, for example equal to or greater than about 420, for example equal to or greater than about 425, for example equal to or greater than about 430,
  • Ink printed on the coated paper may, for example, have a print index up to about 600, for example up to about 550 , for example up to about 500.
  • ink printed on the coated paper may have a print index up to about 490, for example up to about 480, for example up to about 460, for example up to about 470, for example up to about 460, for example up to about 450.
  • Print density and print index are as defined and measured as described above.
  • Ink printed on the coated paper may, for example, have a line quality equal to or greater than about 0.8.
  • ink printed on the coated paper may have a line quality equal to or greater than about 0.85, for example equal to or greater than about 0.9.
  • Ink printed on the coated paper may, for example, have a line quality up to about 1.0, for example up to about 0.99, for example up to about 0.98, for example up to about 0.97, for example up to about 0.96, for example up to about 0.95.
  • Ink printed on the coated paper may, for example, have an edge quality equal to or less than about 15.
  • ink printed on the coated paper may have an edge quality equal to or less than about 14, for example equal to or less than about 13, for example equal to or less than about 12.
  • Ink printed on the coated paper may, for example, have an edge quality equal to or more than about 0.
  • ink printed on the coated paper may have an edge quality equal to or more than about 1 , for example equal to or more than about 2, for example equal to or more than about 3, for example equal to or more than about 4, for example equal to or more than about 5.
  • Line and edge quality are as defined and measured as described above.
  • Ink printed on the coated paper may, for example, have a smudge index after 15 seconds equal to or greater than about 9.
  • ink printed on the coated paper may have a smudge index after 15 seconds equal to or greater than about 9.5, for example equal to or less than about 10.
  • ink printed on the coated paper may have a smudge index after 15 seconds equal to about 10. Smudge index is as defined and measured as described above.
  • paper should be understood to mean all forms of paper, including board, such as, for example, white-lined board and linerboard, cardboard, paperboard, coated board, and the like.
  • board such as, for example, white-lined board and linerboard, cardboard, paperboard, coated board, and the like.
  • coated or uncoated which may be coated using the compositions disclosed herein, including paper suitable for food packaging, perishable goods other than food, e.g., pharmaceutical products and compositions, books, magazines, newspapers and the like, and office papers.
  • the paper may be calendered or super calendared as appropriate; for example super calendered magazine paper for rotogravure and offset printing may be made according to the present methods.
  • Paper suitable for light weight coating (LWC), medium weight coating (MWC) or machine finished pigmentisation (MFP) may also be coated using the present compositions.
  • the paper may, for example, be particularly suitable for ink jet printing.
  • the substrate can be of any basis weight, for example from about 20 gsm to about 300 gsm, for example from about 50 gsm to about 200 gsm, for example from about 60 gsm to about 120 gsm.
  • Paper generally comprises a fibrous substrate, such as, for example, cellulose fibres derived from, for example, wood, rags or grasses.
  • the fibrous substrate may, for example, be derived from recycled pulp or virgin pulp (i.e. pulp which is not derived from a recycled material). Alternatively, the fibrous substrate may comprise a mixture of recycled pulp and virgin pulp.
  • the paper may, for example, be a wood-free paper.
  • the paper substrate may have opposing first and second surfaces.
  • the coating composition may, for example, be present on the first surface, the second surface, or both.
  • the coating composition may, for example, be applied directly to the fibrous substrate.
  • the coating composition may be applied to an intermediate layer between the fibrous substrate and the coating composition.
  • the coating composition may, for example, be a continuous coating on one or more surfaces of the paper.
  • the coating composition may be discontinuous in that it covers only part of one or more surfaces of the paper.
  • the coating composition may, for example, have a coating weight between about 1 gsm and about 20 gsm (grams per m 2 ), for example between about 2 gsm and about 15 gsm, for example between about 5 gsm and about 10 gsm, for example about 10 gsm.
  • the coating composition and coated paper may, for example, be in accordance with any aspect or embodiment described herein, including all combinations and possible variations thereof.
  • the method of making the coating composition may, for example, comprise combining a binder, an alkali earth metal compound such as calcium carbonate, and an anionic dispersant, optionally a cationic polymer, optionally an additional inorganic particulate material and optionally a further additive.
  • the combining may be performed by any suitable mixing techniques as are known in the art.
  • the components of the coating composition may, for example, be combined in any order.
  • a first composition e.g. aqueous slurry
  • the inorganic particulate material such as the alkali earth metal compound (e.g. calcium carbonate)
  • anionic dispersant such as the alkali earth metal compound (e.g. calcium carbonate)
  • optional cationic polymer and the optional further additive
  • the first composition may, for example, be screened to obtain a desired particle size distribution before coating.
  • This first composition may, for example, be anionic.
  • the method of making the coated paper may, for example, comprise coating a fibrous substrate with a coating composition as described herein.
  • the coating composition may be in accordance with any aspect or embodiment described herein, including all combinations and possible variations thereof.
  • the coating process may be carried out using standard techniques which are known to the skilled person.
  • the coating process may also involve calendaring or super- calendaring the coated substrate.
  • Methods of coating paper and other sheet materials, and apparatus for performing the methods, are widely published and well known. Such known methods and apparatus may conveniently be used for preparing coated paper. For example, there is a review of such methods published in Pulp and Paper International, May 1994, page 18 et seq.
  • Sheets may be coated on the sheet forming machine, i.e., "on-machine," or “off-machine” on a coater or coating machine. Use of high solids compositions is desirable in the coating method because it leaves less water to evaporate subsequently.
  • the methods of coating may be performed using an apparatus comprising (i) an application for applying the coating composition to the material to be coated and (ii) a metering device for ensuring that a correct level of coating composition is applied.
  • the metering device is downstream of it.
  • the correct amount of coating composition may be applied to the applicator by the metering device, e.g., as a film press.
  • the paper web support ranges from a backing roll, e.g. via one or two applicators, to nothing (i.e. just tension).
  • the time the coating is in contact with the paper before the excess is finally removed is the dwell time - and this may be short, long or variable.
  • the coating may be added by a coating head at a coating station. According to the quality desired, paper grades are uncoated, singie-coated, double-coated and even triple-coated.
  • the initial coat may have a cheaper formulation and optionally coarser pigment in the coating composition.
  • a coater that is applying coating on each side of the paper will have two or four coating heads, depending on the number of coating layers applied on each side. Most coating heads coat only one side at a time, but some roll coaters (e.g., film presses, gate rolls, and size presses) coat both sides in one pass.
  • coaters examples include, without limitation, air knife coaters, blade coaters, rod coaters, bar coaters, multi-head coaters, roll coaters, roll or blade coaters, cast coaters, laboratory coaters, gravure coaters, kisscoaters, liquid application systems, reverse roll coaters, curtain coaters, spray coaters and extrusion coaters.
  • Water may be added to the solids comprising the coating composition to give a concentration of solids which is preferably such that, when the composition is coated onto a sheet to a desired target coating weight, the composition has a rheology which is suitable to enable the composition to be coated with a pressure (i.e., a blade pressure) of between 1 and 1.5 bar.
  • a pressure i.e., a blade pressure
  • the coating composition may, for example, be printed on the paper product, e.g., printed on a surface of the fibrous substrate of the paper product.
  • the printing may utilize a technique selected from offset printing, flexographic printing or rotogravure printing, thereby allowing the coating composition to be applied to areas where it is required. Offset printing is a widely used printing technique, as will be well understood by a person of ordinary skill in the art.
  • the coating composition is transferred (or "offset") from a plate to a rubber blanket, then to the surface of the substrate (e.g., paper substrate).
  • the substrate may be sheet-fed or web-fed.
  • the web-fed process may be heatset or coldset.
  • the coated paper may be formable or formed into a three-dimensional product, which may be suitable as food grade or pharmaceutical grade packaging.
  • Coated products e.g. coated paper products
  • coated paper and coating compositions may be in accordance with any aspect or embodiment of the present invention, including all combinations and possible variations thereof.
  • the method may, for example, comprise ink jet printing.
  • the method may, for example, comprise offset printing and/or flexographic printing.
  • the method may comprise ink jet printing and one or more of offset printing and flexographic printing.
  • the ink may, for example, be an ink jet ink.
  • the ink may, for example, be a pigment- based ink.
  • the ink may, for example, be a dye-based ink.
  • the coating compositions and/or coated paper of the present invention may, for example, be adapted for printing using an ink jet ink.
  • the coating compositions and/or coated paper of the present invention may, for example, be adapted for printing using a pigment-based ink and/or a dye-based ink.
  • the coating compositions shown in Table 1 were prepared by first dispersing the inorganic particulate material with dispersant to obtain minimum Brookfield viscosity and incorporating the inorganic particulate material into the coating composition. These compositions were used to coat paper by hand draw down (HDD) technique using a wire wound bar. The solids content of the compositions were adjusted until the coatings were obtained with a dry coat weight ranging from about 5 to about 7 gsm.
  • the binder was a cationic starch binder.
  • the calcium carbonate was a precipitated calcium carbonate having a dso of about 1.1 pm, approximately 74 wt% of particles smaller than 2 pm and a specific surface area of about 6.6 m 2 /g.
  • the anionic dispersant was an anionic homopolymer of acrylic acid.
  • the anionic dispersant was a dispersion solution with solids content of about 42.6 wt%.
  • the additional inorganic particulate material used in Composition 2 was an anhydrous kaolin clay having at least about 90 wt% of particles smaller than 2 pm, a dso of about 0.65 pm and a specific surface area of about 14 m 2 /g.
  • the additional inorganic particulate material used in Composition 3 was a hydrous kaolin clay having a dso of about 0.6 pm, at least about 90 wt% of particles smaller than 2 pm and a specific surface area of about 1 1 m 2 /g. Table 1.
  • the black, magenta, cyan and yellow print density, the line quality and the edge quality of ink printed on paper coated with Compositions 1 to 3, an uncoated white top liner board (Control Paper 1 ), a 90 gsm uncoated wood-free paper (Control Paper 2) and a different 90 gsm fine, uncoated wood-free paper (Control Paper 3) was determined by the methods described above.
  • the ink used in these tests was a commercially available water based, pigment-based ink designed for large format ink jet press.
  • the print density test was performed three times for each sample and the average print density noted.
  • the coating compositions shown in Table 3 were prepared as described above.
  • the binder was a cationic starch binder.
  • the calcium carbonate was a precipitated calcium carbonate having a dso of about 1.1 pm, approximately 74 wt% of particles smaller than 2 pm and a specific surface area of about 6.6 m 2 /g.
  • the anionic dispersant was an anionic homopolymer of acrylic acid.
  • the anionic dispersant was a dispersion solution with solids content of about 42.6 wt%.
  • the additional inorganic particulate material used in Composition 4 was an anhydrous kaolin clay having at least about 90 wt% of particles smaller than 2 ⁇ , a dso of about 0.65 Mm and a specific surface area of about 14 m 2 /g.
  • a coating composition comprising:
  • the coating composition has a solids content of at least about 45 wt% and a Brookfield viscosity equal to or less than about 1500 mPa.s.
  • compound has a dso equal to or greater than about 0.4 pm, for example equal to or greater than about 0.6 pm, for example equal to or greater than about 0.8 pm, for example equal to or greater than about 1.0 pm.
  • ink printed on paper coated with the coating composition has a black print density equal to or greater than about 1.0, for example equal to or greater than about 1.1 , for example equal to or greater than about 1.2.
  • the coating composition of any one of paragraphs 1 to 18, wherein ink printed on paper coated with the coating composition has a smudge index after 15 seconds equal to or greater than about 9, for example equal to or greater than about 9.5, for example about 10.
  • the coating composition of any one of paragraphs 1 to 20, wherein the coating composition has a Brookfield viscosity equal to or less than about 1000 mPa.s, for example equal to or less than about 800 mPa.s.
  • the coating composition of any one of paragraphs 1 to 21 wherein the coating composition has a solids content of at least about 50 wt%.
  • Paper comprising a fibrous substrate coated with the coating composition of any one of paragraphs 1 to 22.
  • a method of making the coating composition of any one of paragraphs 1 to 22 comprising combining the binder, alkali earth metal compound and anionic dispersant.
  • a method of making the coated paper of paragraph 23 comprising coating a fibrous substrate with a coating composition of any one of paragraphs 1 to 22.
  • a method of printing comprising applying ink to a paper coated with the coating composition of any one of paragraphs 1 to 22 or the coated paper of paragraph

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Paper (AREA)
  • Paints Or Removers (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)
  • Ink Jet (AREA)

Abstract

Une composition de revêtement comprenant un liant, un composé de métal alcalino-terreux et un dispersant anionique, du papier revêtu de cette composition de revêtement, des procédés de fabrication de cette composition de revêtement et de ce papier et des procédés d'impression.
PCT/GB2016/050042 2015-01-09 2016-01-08 Compositions de revêtement WO2016110711A1 (fr)

Priority Applications (4)

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EP16700665.9A EP3242970A1 (fr) 2015-01-09 2016-01-08 Compositions de revêtement
JP2017536531A JP2018508607A (ja) 2015-01-09 2016-01-08 被覆組成物
MX2017009027A MX2017009027A (es) 2015-01-09 2016-01-08 Composiciones de revestimiento.
BR112017014715A BR112017014715A2 (pt) 2015-01-09 2016-01-08 composições de revestimento

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB1500376.7A GB201500376D0 (en) 2015-01-09 2015-01-09 Coating compositions
GB1500376.7 2015-01-09

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JP (1) JP2018508607A (fr)
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Publication number Priority date Publication date Assignee Title
US11046862B2 (en) 2017-03-01 2021-06-29 Avery Dennison Corporation Print receptive topcoat
CN113683949A (zh) * 2021-09-16 2021-11-23 厦门铜宁消防材料有限公司 一种抗腐蚀微孔防火涂料的制备方法
CN113710457A (zh) * 2019-05-20 2021-11-26 株式会社Tbm 印刷用纸和印刷用纸的制造方法
EP3998160A4 (fr) * 2019-07-08 2023-08-02 TBM Co., Ltd. Feuille d'impression et méthode de fabrication de feuille d'impression
US11958671B2 (en) 2019-07-17 2024-04-16 Tbm Co., Ltd. Laminated structure, food packaging container, and method for producing the same

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US5653795A (en) * 1995-11-16 1997-08-05 Columbia River Carbonates Bulking and opacifying fillers for cellulosic products
WO2004063287A1 (fr) * 2003-01-13 2004-07-29 Imerys Pigments, Inc. Pigment de type carbonate cationique utilise pour former un revetement sur une couche de reception de jet d'encre
WO2006081501A1 (fr) * 2005-01-27 2006-08-03 Imerys Pigments, Inc. Suspensions minerales aqueuses
WO2007050763A1 (fr) * 2005-10-27 2007-05-03 Hewlett-Packard Development Company, L.P. Systeme et procede afin de reduire une tendance a la refloculation du carbonate de calcium nano moulu
WO2008125873A1 (fr) * 2007-04-17 2008-10-23 Imerys Minerals Limited Procédé de meulage
WO2009146416A1 (fr) * 2008-05-29 2009-12-03 International Paper Company Papier à jet d’encre rapidement couché à sec
WO2013121213A1 (fr) * 2012-02-15 2013-08-22 Imerys Minerals Limited Compositions de pigment

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FR2692605A1 (fr) * 1992-06-23 1993-12-24 Protex Manuf Prod Chimiq Dispersions améliorées de charges minérales pour l'industrie papetière.
US5653795A (en) * 1995-11-16 1997-08-05 Columbia River Carbonates Bulking and opacifying fillers for cellulosic products
WO2004063287A1 (fr) * 2003-01-13 2004-07-29 Imerys Pigments, Inc. Pigment de type carbonate cationique utilise pour former un revetement sur une couche de reception de jet d'encre
WO2006081501A1 (fr) * 2005-01-27 2006-08-03 Imerys Pigments, Inc. Suspensions minerales aqueuses
WO2007050763A1 (fr) * 2005-10-27 2007-05-03 Hewlett-Packard Development Company, L.P. Systeme et procede afin de reduire une tendance a la refloculation du carbonate de calcium nano moulu
WO2008125873A1 (fr) * 2007-04-17 2008-10-23 Imerys Minerals Limited Procédé de meulage
WO2009146416A1 (fr) * 2008-05-29 2009-12-03 International Paper Company Papier à jet d’encre rapidement couché à sec
WO2013121213A1 (fr) * 2012-02-15 2013-08-22 Imerys Minerals Limited Compositions de pigment

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11046862B2 (en) 2017-03-01 2021-06-29 Avery Dennison Corporation Print receptive topcoat
CN113710457A (zh) * 2019-05-20 2021-11-26 株式会社Tbm 印刷用纸和印刷用纸的制造方法
EP3998160A4 (fr) * 2019-07-08 2023-08-02 TBM Co., Ltd. Feuille d'impression et méthode de fabrication de feuille d'impression
US11958671B2 (en) 2019-07-17 2024-04-16 Tbm Co., Ltd. Laminated structure, food packaging container, and method for producing the same
CN113683949A (zh) * 2021-09-16 2021-11-23 厦门铜宁消防材料有限公司 一种抗腐蚀微孔防火涂料的制备方法

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BR112017014715A2 (pt) 2018-02-06
JP2018508607A (ja) 2018-03-29
GB201500376D0 (en) 2015-02-25
MX2017009027A (es) 2018-02-09
EP3242970A1 (fr) 2017-11-15

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