(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
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`(I 9) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`17 April 2003 (17.04.2003)
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`
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`(10) International Publication Number
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`WO 03/031191 A2
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`(51)
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`International Patent Classification7:
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`B41M 5/00
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`(81)
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`(21)
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`International Application Number:
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`PCT/US02/32452
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`(22)
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`International Filing Date: 9 October 2002 (09.10.2002)
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`(25)
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`Filing Language:
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`(26)
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`Publication Language:
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`English
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`English
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`(84)
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`(30)
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`Priority Data:
`60/328,180
`
`9 October 2001 (09.10.2001)
`
`US
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`(71)
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`Applicant: KANZAKI SPECIALTY PAPERS INC.
`[ifUS]; 20 Cummings Street, Ware, MA 01082—2002
`(US).
`
`(72)
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`Inventors: CUCH, Simon, R.; 15 Bent Tree Drive, East
`Longmeadow, MA 01028 (US). STEVENS, George, R.,
`Jr.; 28 Pomeroy Street, Wilbraham, MA 01095 (US).
`
`Designated States (national): AE, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CO, CR, CU,
`CZ, DE, DK, DM, DZ, EC, EE, ES, FI, GB, GD, GE, GH,
`GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC,
`LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW,
`MX, MZ, NO, NZ, OM, PH, PL, PT, RO, RU, SD, SE, SG,
`SI, SK, SL, TJ, TM, TN, TR, TT, TZ, UA, UG, UZ, VN,
`YU, ZA, ZM, ZW.
`
`Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZM, ZW),
`Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`European patent (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
`ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE, SK,
`TR), OAPI patent (BF, BJ, CF, CG, CI, CM, GA, GN, GQ,
`GW, ML, MR, NE, SN, TD, TG).
`
`Published:
`without international search report and to be republished
`upon receipt of that report
`
`(74)
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`Agents: BONZAGNI, Mary, R. et al.; 171 Dwight Road,
`Suite 302, Longmeadow, MA 01106—1700 (US).
`
`For two-letter codes and other abbreviations, refer to the ”Guid-
`ance Notes on Codes andAbbreviations " appearing at the begin-
`ning ofeach regular issue ofthe PCT Gazette.
`
`(54) Title: AN INK JET RECORDING MATERIAL SUITABLE FOR USE IN WIDE FORMAT PRINTING APPLICATIONS
`
`03/031191A2
`
`(57) Abstract: An aqueous coating formulation for use in preparing ink jet recording materials is provided. The coating formula—
`tion, which employs porous pigments and/or metal oxide gels in combination with inorganic pigments (i.e., calcium carbonate and
`mixtures of calcium carbonate and alumina), has a relatively high binder—to—pigment dry weight ratio. An ink jet recording material
`0 prepared using such an aqueous coating formulation is also provided. The ink jet recording material demonstrates good printabil—
`ity and provides images having excellent water and humidity resistance and high image densities. In a preferred embodiment, the
`3
`inventive recording material further demonstrates good light or fade resistance.
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`W0 03/031191
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`PCT/US02/32452
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`AN INK JET RECORDING MATERIAL SUITABLE FOR USE IN WIDE
`FORMAT PRINTING APPLICATIONS
`
`[0001]
`
`This application claims priority from US. Provisional Patent Application
`
`Serial No. 60/328,180, filed October 9, 2001.
`
`Related Application
`
`Field of the Invention
`
`[0002]
`
`The present invention generally relates to an aqueous coating formulation for
`
`use in preparing ink jet recording materials. The ink jet recording materials are suitable for
`
`use in wide format printing applications, demonstrate good printability and can provide
`
`images having excellent water and humidity resistance and high image densities.
`
`In a
`
`preferred embodiment, the inventive recording material further demonstrates good light or
`
`fade resistance.
`
`Background of the Invention
`
`[0003]
`
`Wide format ink jet recording materials are typically manufactured as wide
`
`rolls (i.e., greater than or equal to 24 inches in width), and are roll-fed into large printers for
`
`imaging. These materials are commonly used in commercial settings for applications
`
`including large advertisements, movie theater posters, outdoor signage and the like.
`
`[0004]
`
`Unlike narrow format ink jet recording materials, wide format materials,
`
`which are intended for long distance viewing, are required to meet more rigorous
`
`performance standards. For example, long distance viewing demands heightened acuity or
`
`sharpness in formed images and increased color gamut, background brightness and
`
`whiteness. In addition, wide format inkjet materials are ofien exposed to different use
`
`environments (e.g., outdoor use), which place additional demands on these materials in terms
`
`of color stability, resistance to light—induced fading, waterfastness, humidity resistance,
`
`abrasion resistance, and the like. It is further noted that wide format ink jet recording
`
`materials may encounter more ink per unit area when run through certain commercial printers
`
`and thus must effectively address problems with poor image quality, color bleed, smearing
`
`and cockle.
`
`[0005]
`
`Prior art attempts to meet these more rigorous performance requirements
`
`include the use of fluorescent whitening agents in ink jet coatings to increase the background
`
`brightness and whiteness of resulting recording materials. Fluorescent whitening agents,
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`however, degrade and, to a lesser extent, react with other coating components thereby
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`contributing to the yellowing (i.e., poor light or fade resistance) of the resulting inkjet
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`recording material.
`
`[0006]
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`Efforts to minimize this effect include decreasing the level of fluorescent
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`whitening agents in the inkjet coating. Unfortunately, the corresponding decrease in
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`background brightness/whiteness renders such materials less suitable for use in wide format
`
`printing applications. Attempts to correct this deficiency by using superior or more
`
`expensive grades of exceptionally white and bright base paper, adversely impacts upon the
`
`economics of these materials.
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`10
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`[0007]
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`US. Patent No. 6,129,785 to Schliesman et al. discloses a low pH aqueous
`
`suspension for application to optionally sized substrates, such as paper. The aqueous
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`suspension comprises: absorptive silica pigment (e.g., a mixture ofz 75 % silica gel having a
`
`pore volume of 0.5 to 1.5 cc/g and 2 10 % alumina or alumina hydrate), a polyvinyl alcohol
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`binder (e. g., low molecular weight, partially hydrolyzed polyvinyl alcohols) and a cationic
`
`fixing agent (e. g., polydiallyl dimethyl ammonium chloride), dispersed at low pH ranges of
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`4.0 to 7.5. The acidic pH of the aqueous suspension is believed to enhance cationic function
`
`resulting in rapid dry times and improved ink hold out and color density.
`
`Recording materials prepared from low pH coating compositions, however,
`[0008]
`are less suitable for use in wide format printing applications where these materials tend to'be
`
`less stable and thus more susceptible to fading and yellowing. Moreover, images formed on
`
`the recording materials described in Schliesman er al. have image densities that are too low to
`
`render these materials suitable for use in wide format printing applications.
`
`[0009]
`
`In view of the above, a need exists for bright, white inkjet recording
`
`materials, which are not susceptible to fading or yellowing, and which provide images having
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`high image densities.
`
`[0010]
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`It is, therefore, an object of the present invention to provide such an ink jet
`
`recording material.
`
`[0011]
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`It is a more particular object to provide an ink jet recording material suitable
`
`for use in wide format printing applications, which demonstrates good printability and which
`
`can provide images having excellent water and humidity resistance and high image densities.
`
`[0012]
`
`It is yet a more particular object of the present invention to provide an
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`economical, bright, white inkjet recording material, which demonstrates good printability
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`and good light or fade resistance, and which provides images having excellent water and
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`humidity resistance and high image densities.
`
`SUMMARY OF THE INVENTION
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`5
`
`[0013]
`
`The present invention therefore provides an aqueous coating formulation
`
`having a relatively high binder—to-pigment dry weight ratio, which comprises:
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`(i)
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`from about 45 to about 80 % by dry wt., based on the total dry
`
`weight of the coating formulation, of a pigment composition comprising from
`
`about 10 to about 90 % by dry wt., based on the total dry weight of the
`
`pigment composition, of a first pigment selected from the group of porous
`
`organic pigments, porous inorganic pigments, metal oxide gels and mixtures
`
`thereof, and from about 90 to about 10 % by dry wt., based on the total dry
`
`weight of the pigment composition, of a second pigment selected from the
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`group of calcium carbonate and mixtures of calcium carbonate and alumina,
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`wherein the sum of the pigment composition components total 100
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`% by dry wt.;
`
`(ii)
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`from about 10 to about 45 % by dry wt., based on the total dry
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`weight of the coating formulation, of a water-soluble binder selected from the
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`group of super, fully and partially hydrolyzed polyvinyl alcohols and mixtures
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`thereof and, optionally, one or more cationic acrylic resins;
`
`(iii)
`
`from about 1 to about 25 % by dry wt., based on the total dry
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`weight of the coating formulation, of a cationic resin;
`
`(iv)
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`an effective amount of an optionally fluorescent whitening agent; and
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`(v)
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`optionally, an effective amount of a blueing dye,
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`wherein, the sum of the coating formulation components total 100 % by dry
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`wt.,
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`wherein, the binder/pigment dry weight ratio in the coating formulation ranges
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`from about 1:8 to about 1:1, and
`
`wherein, when an optionally fluorescent whitening agent and a blueing
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`30
`
`dye are present
`
`in the coating formulation,
`
`the optionally fluorescent whitening
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`agent/blueing dye dry weight ratio in the formulation ranges from about 1:1 to about
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`1000:].
`
`[0014]
`
`The present invention also provides a method for preparing the aqueous
`
`coating formulation described above, which comprises:
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`(i)
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`preparing an aqueous solution of the optionally fluorescent whitening
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`agent; and then
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`(ii)
`
`adding the remaining components in the following order of addition:
`
`cationic resin, first pigment, second pigment, remaining components.
`
`[0015]
`
`The present invention further provides an ink jet recording material, which
`
`comprises:
`
`(a)
`
`(b)
`
`a substrate;
`
`optionally, one or more undercoat layers located on the substrate,
`
`which is/are prepared using an aqueous coating formulation comprising:
`
`(i)
`
`(ii)
`
`(iii)
`
`(iv)
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`one or more pigments;
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`one or more binders;
`
`optionally, one or more dispersing agents; and
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`an effective amount of an optionally fluorescent whitening
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`agent
`
`wherein, the sum of the coating formulation components total 100 %
`
`by dry wt., and
`
`wherein, the pigment/binder dry weight ratio in the coating formulation
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`ranges from about 1:1 to about 20:]; and
`
`(0)
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`one or more ink jet receptive layers located on the optional undercoat
`
`layer(s) and/or on the substrate, which is/are prepared using the aqueous
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`coating formulation described above.
`
`[0016]
`
`The foregoing and other features and advantages of the present invention will
`
`become more apparent from the following description.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`[0017]
`
`Although the present inventive inkjet recording material will be described
`
`herein mainly in reference to wide format printing applications, it is not so limited. The
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`inventive material can be used in any application, including narrow format printing
`
`applications, where good printability and sharp, water and humidity resistant images, are
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`desired.
`
`[0018]
`
`As is well known to those skilled in the art, high binder-to-pigment ratios in
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`inkjet coating formulations limit the machine coatability of such coating formulations and
`
`serve to reduce the maximum ink absorbency, interfere with the ink drying time and reduce
`
`the maximum coat weight of the resulting inkjet layer. By way of the present invention, it
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`has been discovered that coating formulations having relatively high binder-to-pigment dry
`
`weight ratios, which employ porous pigments and/or metal oxide gels in combination with
`
`inorganic pigments (i.e., calcium carbonate and mixtures of calcium carbonate and alumina)
`
`produce inkjet receptive layers which demonstrate good printability and which provide
`
`images having excellent water and humidity resistance and high image densities.
`
`[0019]
`
`Suitable porous organic pigments for use as the first pigment in the pigment
`
`composition of the coating formulation used to prepare the ink jet receptive layer of the
`
`present invention include acrylic resins such as polymethyl methacrylate, polymethylacrylate,
`
`polyacrylonitrile, poly(vinylpolypyrrolidone), styrene resins such as polystyrene,
`
`.
`
`polymethylstyrene and the like, as well as styrene-acrylic resins, urea-formaldehyde resins,
`
`polyvinyl chlorides, polycarbonates, etc. Suitable porous inorganic pigments include porous
`
`alumina, porous sodium aluminosilicate, porous calcium carbonate, porous clays, porous
`
`magnesium carbonate, porous synthetic amorphous silica and the like.
`
`[0020]
`
`The average diameter of pores in the porous organic and inorganic pigments is
`
`preferably from about 1 to about 800 nanometers, while the volume of pores in these
`
`pigments is preferably from about 0.4 to about 3.0 cubic centimeters per gram (cc/g).
`
`[0021]
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`Metal oxide gels, suitable for use as the first pigment in the pigment
`
`composition of the subject coating formulation include alumina gels, silica gels, polymeric
`
`gels such as melamine formaldehyde (M-F) gels, phenol-furfiiral (P-F) gels, resorcinol-
`
`formaldehyde (R-F) gels, urea-formaldehyde (U-F) gels, titania gels and the like.
`
`[0022]
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`In a preferred embodiment, the first pigment is a metal oxide gel.
`
`In yet a
`
`more preferred embodiment, the metal oxide gel is a silica gel having a surface area ranging
`
`from about 200 to about 800 square meters per gram (mZ/g), a pore volume ranging from
`
`about 0.4 to about 3.0 cc/g, an average particle size ranging from about 1 to about 17 [A and a
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`pH ranging from about 2.5 to about 10.5.
`
`[0023]
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`Specific preferred examples of silica gels having surface areas, pore volumes,
`
`average particle sizes and pHs falling within the ranges specified above, include SYLOID
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`620 and 234 wax-free silica gels, SYLOID 7000 wax surface-treated silica gels and SYLOID
`
`74 (grade 4500, 5500 and 6500) silica gels, marketed by Grace Davison, W.R. Grace & Co.,
`
`7500 Grace Drive, Columbia, MD 21044 ("Grace Davison").
`
`[0024]
`
`The first pigment is present in the pigment composition in an amount ranging
`
`from about 10 to about 90 % by dry wt., preferably from about 20 to about 80 % by dry wt.,
`
`based on the total dry weight of the pigment composition. The present inventor has found
`
`that if the first pigment is employed in an amount which exceeds 90 % by dry wt., a decrease
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`in optical or image densities will be observed, and if the first pigment is employed in an
`
`amount which falls below 10 % by dry wt., an increase in the degree of wicking or spread of
`
`water or ink will also be observed.
`
`[0025]
`
`The pigment composition of the coating formulation of the present invention
`
`also contains a porous or non-porous second pigment which appears to aid in the preservation
`
`or maintenance of an open structure in the ink jet receptive layer, upon drying, even at high
`
`binder-to—pigment dry weight ratios. The second pigment is selected from the group
`
`including calcium carbonate and mixtures of calcium carbonate and alumina.
`
`[0026]
`
`In a preferred embodiment, the second pigment is calcium carbonate and,
`
`more preferably, is a precipitated calcium carbonate (PCC) pigment possessing a surface area
`
`ranging from about 10 to about 300 square meters per gram (ml/g), a particle size ranging
`
`from about 0.1 to about 5 ,LL and rheology of a thixotropic nature thus facilitating application
`
`of the resulting coating formulation under high shear conditions such as air knife or blade
`coaters.
`
`[0027]
`
`Specific examples of PCCs possessing rheoiogy of a thixotropic nature are
`
`available from Minerals Technologies Inc., 35 Highland Avenue, Bethlehem, PA 18017,
`
`under the trade designation JETCOAT 30 precipitated calcium carbonate, and from Fitz
`
`Chem Corporation, 185 Industrial Drive, Elmhurst, IL 60126-1601, under the trade
`
`designation MAGNUM GLOSS precipitated calcium carbonate.
`
`[0028]
`
`In another preferred embodiment, the second pigment is a mixture comprising
`
`from about 60 to about 99 % by dry wt. (and more preferably from about 80 to about 95 % by
`
`dry wt.) of calcium carbonate and from about 40 to about 1 % by dry wt. (and more
`
`preferably from about 20 to about 5 % by dry wt.) of an alumina pigment.
`
`[0029]
`
`Anhydrous alumina and alumina hydrate pigments are preferred. As the
`
`an hydrous alumina there may be used any of the various crystalline alumina such as oc-
`
`alumina, B-alumina and y-alumina. As the alumina hydrate there may be used either alumina
`
`monohydrate or trihydrate. Examples of the alumina monohydrate include pseudoboehmite,
`
`boehmite and diaspore. Examples of the alumina trihydrate include gibbsite and bayerite.
`
`Preferred among these alumina pigments is alumina trihydrate.
`
`[0030]
`
`The average particle diameter of the alumina pigment to be used herein is
`
`preferably from about 0.1 to about 3.0 M, more preferably from about 0.4 to about 2.0 it. The
`
`alumina pigment to be used herein may or may not be porous but is preferably porous. The
`
`average diameter of pores in the particulate alumina pigment is preferably from about 0.5 to
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`about 300 nanometers. The volume of pores in the particulate alumina pigment is preferably
`
`from about 0.1 to about 2.1 cc/g.
`
`[0031]
`
`The second pigment is present in the pigment composition in an amount
`
`ranging from 90 to about 10 % by dry wt., preferably from about 80 to about 20 % by dry wt.,
`
`based on the total dry weight of the pigment composition. The present inventor has found
`
`that if the second pigment is employed in an amount below 10 % by dry wt., a decrease in
`
`optical or image densities will be observed, and if the second pigment is employed in an
`
`amount above 90 % by dry wt., an increase in the degree of wicking will also be observed.
`
`[0032]
`
`The subject pigment composition may contain additional components
`
`including, but not limited to, barium sulfate, clays, talc, titanium dioxide, zinc oxide and
`
`mixtures thereof.
`
`[0033]
`
`The pigment composition is present in the coating formulation in an amount
`
`ranging from about 45 to about 80 % by dry wt., preferably from about 50 to about 75 % by
`
`dry wt., based on the total dry weight of the coating formulation.
`
`[0034]
`
`The water—soluble binder ofthe coating formulation ofthe present invention is
`
`selected from the group consisting of super, fully and partially hydrolyzed polyvinyl alcohols
`
`and mixtures thereof and, optionally, one or more cationic acrylic resins.
`
`[0035]
`
`The term "super hydrolyzed," as used herein, is intended to refer to those
`
`polyvinyl alcohols having a % hydrolysis ranging from about 99 to about 100, while the term
`
`"fully hydrolyzed" refers to a % hydrolysis ranging from about 97 to about 99. The term
`
`"partially hydrolyzed," on the other hand, denotes a polyvinyl alcohol having a %hydrolysis
`
`of from about 70 to about 96.
`
`[0036]
`
`The super hydrolyzed polyvinyl alcohols of the present invention preferably
`
`have a % hydrolysis of from about 99.3 to about 99.6, while the fully hydrolyzed polyvinyl
`
`alcohols preferably have a % hydrolysis of from about 98 to about 98.8. The partially
`
`hydrolyzed polyvinyl alcohols preferably have a % hydrolysis of from about 84 to about 92.
`
`[0037]
`
`The super, fully and partially hydrolyzed polyvinyl alcohols of the water-
`
`soluble binder have medium-to-low molecular weights which range from about 5,000 to
`
`about 186,000 (preferably from about 13,000 to about 150,000) and may be modified by
`
`adding a cation thereto. More specifically, the polyvinyl alcohols may be modified by
`
`silanol, carboxy and/0r quaternary amine groups.
`
`[0038]
`
`Specific preferred examples of super, fully and partially hydrolyzed, medium-
`
`to-low molecular weight, polyvinyl alcohols are available from Air Products and Chemicals,
`
`Inc., 7201 Hamilton Blvd., Allentown, PA 18196-1501 ("Air Products") and are sold under
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`the trade designations AIRVOL 125 super hydrolyzed, medium molecular weight, polyvinyl
`
`alcohol, AIRVOL 325 fully hydrolyzed, medium molecular weight, polyvinyl alcohol,
`
`AIRVOL 523 partially hydrolyzed, medium molecular weight, polyvinyl alcohol and
`
`AIRVOL 205 partially hydrolyzed, low molecular weight, polyvinyl alcohol.
`
`[0039]
`
`The water-soluble binder may fiirther comprise from about 1 to about 50% by
`
`dry wt., based on the total dry weight of the water-soluble binder, of a cationic acrylic resin.
`
`The cationic acrylic resin serves to fix ink jet dyes and appears to enhance the color range or
`
`gamut of printed media. Suitable examples of such cationic acrylic resins include cationic
`
`styrene-acrylic resins, cationic styrene—acrylic copolymers, amide-modified cationic styrene-
`
`acrylic resins and cationic vinyl acrylic resins. Preferred cationic acrylic resins are cationic
`
`styrene-acrylic copolymers, which are available from Westvaco Corporation, Chemical
`
`Division, P.O. Box 70848, Charlestown Heights, SC 29415, and are sold under the trade
`
`designation TRUDOT P2605 cationic styrene-acrylic copolymers.
`
`[0040]
`
`The water-soluble binder may contain additional components (e. g., alginate,
`
`biocides, casein, cellulose derivatives, CMC, hydroxymethyl cellulose, hydroxypropyl
`
`cellulose, water soluble gums, latex, amphoteric latex, maleic anhydride resins, melamine
`
`resins, polyacrylamide resins, polyester resins, polyvinyl acetate, polyvinyl pyrrolidone,
`
`polyvinyl pyrrolidone vinyl acetate copolymers, modified starch, ethoxylated starch, cationic
`I starch, oxidized starch and blends thereof) provided any such additional components(s) dOes
`
`not adversely impact upon the desirable properties of the binder.
`
`[0041]
`
`In a more preferred embodiment, the water-soluble binder comprises:
`
`(a)
`
`from about 10 to about 90% by dry wt. (more preferably from about 20
`
`to about 80 % by dry wt.) of a super hydrolyzed, medium viscosity polyvinyl
`
`alcohol;
`
`(b)
`
`from about 10 to about 70% by dry wt. (more preferably from about 15
`
`to about 65 % by dry wt.) ofa partially hydrolyzed, medium viscosity
`
`polyvinyl alcohol; and
`
`(c)
`
`from about 0 to about 20% by dry wt. (more preferably from about 5 to
`
`about 15 % by dry wt.) ofa partially hydrolyzed, low viscosity polyvinyl
`
`alcohol.
`
`[0042]
`
`The water-soluble binder preferably has a medium—to—low Viscosity. More
`
`specifically, the binder has a preferred viscosity ranging from about 3 to about 40 centipoise
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`(cps), as measured by a Brookfield Viscosimeter, model number DV-II+, using a 4 %
`
`polyvinyl alcohol aqueous solution at 20°C.
`
`[0043]
`
`The binder/pigment dry weight ratio in the coating formulation used to prepare
`
`the ink jet receptive layer of the present invention ranges from about 1:8 to about 1:],
`
`preferably ranges from about 1:6 to about 1:15, and more preferably ranges from about 1: 2.8
`
`to about 121.8.
`
`[0044]
`
`The present inventor has found that if the binder/pigment ratio exceeds 1:1
`
`(i.e., the binder is present in an amount which is greater than the amount of pigment), an
`
`increase in the degree of wicking and intercolor bleeding will be observed, while if the ratio
`
`falls below 1:8 (i. e., the binder is present in an amount which is less than 12.5 % ofthe
`
`amount of pigment), a decrease in optical or image densities will be observed.
`
`[0045]
`
`The water-soluble binder is present in the coating formulation in an amount
`
`ranging from about 10 to about 45 % by dry wt., preferably from about 15 to about 40 % by
`
`wt., based on the total dry weight of the coating formulation.
`
`[0046]
`
`The cationic resin of the coating formulation of the present invention serves as
`
`a fixing agent of ink and improves the fixing of recorded images and water resistance.
`
`[0047]
`
`Preferred cationic resins include polyvinyl benzyl trimethyl ammonium
`
`chloride, polydiallyl dimethyl ammonium chloride, polymethacryloxyethyl hydroxy
`
`ethyldiammonium chloride, quaternary acrylic copolymer latex, amidocpichlohydrin
`
`copolymer, dimethylaminoethylmethacrylate copolymer, vinyl pyrrolidone
`
`dimethylaminoethylmethacrylate copolymer, polyallylamine, polyvinylamine, Vinyl amine
`
`acrylonitrile copolymers, polyalkylene imine polymers, polyalkylene polyamine polymers,
`
`polyalkylene polyamide dicyandiamide copolymers, polyamide dicyandiamide copolymers,
`
`quaternary ammonium polymers and blends thereof. In a preferred embodiment, the cationic
`
`resin is a quaternary ammonium polymer and, more preferably, is polydiallyl dimethyl
`
`ammonium chloride marketed by Calgon Corporation, 2015 Christine Drive, Harleysville,
`
`PA 19438 under the trade designation CP-1030.
`
`[0048]
`
`The cationic resin is present in the coating formulation in an amount ranging
`
`from about 1 to about 25 % by dry wt., preferably from about 3 to about 15 % by dry wt.,
`
`based on the total dry weight of the coating formulation. If the cationic resin is present in an
`
`amount below 1 % by dry wt., the water resistance of the composition is very poor, and if the
`
`cationic resin is present in an amount above 25 % by dry wt., printed image quality is
`
`adversely affected.
`
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`WO 03/031191
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`PCT/USO2/32452
`
`[0049]
`
`The optionally fluorescent whitening agent is added to the coating formulation
`
`of the present invention to increase the whiteness, brightness and bluish shade of the resulting
`
`inkjet recording material. Examples of such whitening agents include disulfonated,
`
`tetrasulfonated and hexasulfonated stilbene derivatives. In a preferred embodiment, the agent
`
`is a hexasulfonated stilbene derivative, which is available from Ciba Specialty Chemical
`
`Corp., 540 White Plains Road, Tarrytown, NY 10591 ("Ciba Specialty"), under the product
`
`designation TTNOPAL ABP—A, and is present in an amount ranging from about 0.01 to about
`
`1.5 % by dry wt., preferably from about 0.1 to about 0.8 % by dry wt., based on the total dry
`
`weight of the coating formulation.
`
`[0050]
`
`The whitening agent may employ a fluorescing agent, which absorbs energy in
`
`the UV region and emits light largely in the blue region.
`
`[0051]
`
`In a preferred embodiment, the coating formulation further comprises from
`
`about 0.001 to about 0.05 % by dry wt., preferably from about 0.002 to about 0.007 % by dry
`
`wt., based on the total dry weight of the coating formulation, of a blueing dye. The blueing
`
`dye serves to increase the whiteness of the ink jet recording material. Suitable examples of
`
`such dyes include cobalt blue, copper phthalocyanine, metal—free phthalocyanine, oxide
`
`cobalt phosphate, dye complex salts (i.e., dyes precipitated with phosphomolybdic,
`
`phosphotungstic, phospho-molybdotungstic acids), quinacridone pigments, ultramarine blue
`
`and mixtures thereof. Preferred blueing dyes have good lightfastness and are available from:
`
`Ciba Specialty, under the product designations IRGALITE BLUE RL PST copper
`
`phthalocyanine dyestuff dispersion and IRGALITE VIOLET RM and IRGALITE RED B-F L
`
`arylamide pigment dispersions; and Bayer Industrial Chemicals, under the product
`
`designations PONOLITI-I RED WC quinacridone pigment dispersion and PONOLITH BLUE
`
`RDC copper phthalocyanine pigment dispersion.
`
`[0052]
`
`It is noted that when both the optionally fluorescent whitening agent and the
`
`blueing dye are present in the coating formulation, the whitening agent/blueing dye weight
`
`ratio preferably ranges from about 1:1 to about 1000:], and more preferably ranges from
`
`about 2:1 to about 800:1. If the whitening agent/blueing dye ratio falls below 1:], the
`
`resulting inkjet recording material displays lower brightness and whiteness, and if the ratio
`
`exceeds 1000:] , the resulting recording materials demonstrates poor lightfastness.
`
`[0053]
`
`In addition to the above components, the coating formulation of the present
`
`invention can advantageously contain other additives such as antioxidants, antistatic agents,
`
`crosslinking agents, defoaming agents, dispersing agents, fragrances, mold inhibitors, slip
`
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`WO 03/031191
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`PCT/USO2/32452
`
`5
`
`10
`
`15
`
`20
`
`agents, UV absorbers and wetting agents. However, some such additives may adversely
`
`impact upon the desirable properties of the resulting ink jet receptive layer.
`
`[0054]
`
`In a most preferred embodiment, the coating formulation used to prepare the
`
`inkjet receptive layer of the present invention comprises:
`
`(1)
`
`from about 50 to about 75 % by dry wt. of a pigment composition
`
`comprising:
`
`(a)
`
`from about 20 to about 80 % by dry wt., based on the total
`
`dry weight of the pigment composition, of silica gel; and
`
`(b)
`
`from about 80 to about 20 % by dry wt., based on the total
`
`dry weight of the pigment composition, of precipitated calcium
`
`carbonate,
`
`(2)
`
`from about 15 to about 40 % by dry wt. of a water-soluble binder
`
`comprising:
`
`(a)
`
`from about 20 to about 70 % by dry wt., based on the total dry
`
`weight ofthe binder, ofa super and/or fully hydrolyzed, medium
`
`molecular weight polyvinyl alcohol;
`
`(b)
`
`from about 70 to about 25 % by dry wt., based on the total dry
`
`weight of the binder, of a partially hydrolyzed, medium-to—low
`
`molecular weight, polyvinyl alcohol; and
`
`(c)
`
`from about 5 to about 35 % by dry wt., based on the total dry
`
`weight of the binder, of a cationic styrene acrylic copolymer,
`
`(3)
`
`from about 3 to about 15 % by dry wt. ofpolydiallyl dimethyl
`
`ammonium chloride,
`
`(4)
`
`from about 0.01 to about 1.5 % by dry wt. of a hexasulfonated
`
`25
`
`stilbene derivative, and
`
`(5)
`
`from about 0.001 to about 0.05 % by dry wt. of a phthalocyanine dye
`
`stuff,
`
`wherein, the binder/pigment composition weight ratio ranges from about
`
`1:6 to about 1:15, and
`
`30
`
`wherein, the whitening agent/blueing dye weight ratio ranges from about
`
`2:1 to about 800:1.
`
`[0055]
`
`The inkjet receptive layer coating formulation is made by mixing the
`
`components with water so as to obtain an aqueous composition having a solids content
`
`ranging from about 15 to about 35 % (preferably from about 15 to about 20 %), based on the
`
`1 1
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`WO 03/031191
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`PCT/US02/32452
`
`total dry weight of the coating formulation. The pH of the aqueous composition is between 6
`
`and 10, and preferably is between 6.5 and 8.
`
`[0056]
`
`In a preferred embodiment, the coating formulation is made by first preparing
`
`an aqueous solution or emulsion of the optionally fluorescent Whitening agent and then by
`
`adding the remaining components in the following sequence: cationic resin (e.g., polydiallyl
`
`dimethyl ammonium chloride), first pigment (e.g., silica gel), second pigment (e.g., PCC),
`
`remaining ingredients or components. This sequence of addition is preferred where the
`
`cationic resin is somewhat incompatible with the optionally fluorescent whitening agent but
`
`aids in the dispersion ofthe first pigment.
`
`10
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`15
`
`[0057]
`
`In order to avoid degradation in ink absorptivity caused by the use of
`
`excessive amounts of coating,
`
`it
`
`is preferred that the ink jet coating composition of the
`
`present invention be applied so as to achieve an average coat weight that ranges from about 2
`
`to about 14 g/m2, based on the total dry weight of the coating composition.
`
`[0058]
`
`Substrates useful in the present invention are coatable substrates, examples of
`
`which include, without limitation, paper, cardboard, corrugated board, plastic film, metal
`
`film, foil face stocks and label stocks.
`
`[0059]
`
`The substrate preferably has a thickness ranging from about 50 to about 300 a,
`
`a basis weight ranging from about 40 to about 240 grams per square meter (g/mz), a surface
`
`smoothness of from about 15 to about 150 Bekk seconds and a Cobb sizing of from about 25
`
`20
`
`to about 150 g/m2.
`
`25
`
`30
`
`[0060]
`
`The optional undercoat layer of the inkjet recording material of the present
`
`invention serves to reduce cockling and enhance or improve the whiteness, brightness,
`
`opacity, inkjet ink strike-through and lightfastness of the resulting inkjet recording material.
`
`[0061]
`
`When an undercoat layer is employed, the amount of optionally fluorescent
`
`whitening agent in the undercoat layer is greater than the amount of whitening agent in the
`
`ink receptive layer.
`
`[0062