Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5254—Macromolecular coatings characterised by the use of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers

Definitions

• This invention relates to a recording sheet for use in ink jet printing. More particularly, this invention relates to recording medium having improved coatability, drying characteristics, and print quality. In a preferred embodiment, the invention provides a reactive ink jet recording sheet having improved durability, water-fastness and smear resistance.
• Ink jet printing is a non-impact method for recording information in response to an electronic signal, such as that generated by a computer.
• the electronic signal produces droplets of ink that are deposited on a substrate such as paper.
• Ink jet printers have found broad commercial acceptance due to their rapid printing speeds, relatively quiet operation, graphic capability and low cost.
• inks typically black, cyan, magenta and yellow
• a printing medium typically ordinary paper.
• the inks primarily are composed of water, a colorant that may be a dye or pigment dispersion, generally contain a polyhydric alcohol to prevent nozzle clogging, and may contain various adjuvants.
• a colorant that may be a dye or pigment dispersion
• Such inks and ordinary paper are well suited for desk-top publishing, as currently practiced, wherein only a small portion of the paper receives printed text and graphic information.
• the printing medium will receive substantially more of the black and colored inks to accurately reproduce the various hues, tints, and colors contained in a typical colored picture.
• the printing medium will be expected to receive up to 200% or more coverage in conventional commercial printing.
• Ordinary paperstock is not suitable for such high quality applications for a number of reasons. Water disrupts the paper structure, causing "cockle” that affects appearance of the paper and, in extreme cases, may actually cause the paper to distort to the extent that it contacts the ink jet pen, disrupting the printing process. Also, the paper may not absorb water sufficiently quickly to achieve the desired printing speed, or may cause flooding of the paper surface, which adversely affects image quality. Moreover, wicking of ink into the paper may cause paper to "show through" into the printed image, detracting from image quality. There also is a need for the printed text and pictures to be more robust; e.g., exhibit better handleability, water fastness, and smear resistance. Accordingly, there is a need for improved media for ink jet printing in general, and particularly for applications of ink jet printing technologies to commercial printing and to reproduction of pictorial information.
• DE 3 016 766 discloses an ink jet recording sheet having a water-soluble polymer layer
• JP 63 242,585 discloses a recording material in which the ink receptive layer is formed by a hydrophilic or water-soluble polymer.
• U.S. 4,503,111 discloses a recording medium having a surface coated with polyvinylpyrrolidone and a compatible matrix-forming hydrophilic polymer, such as gelatin or polyvinyl alcohol. Inked images applied to such coatings are relatively slow to dry, however, and exhibit poor waterfastness and poor handleabilty due to the tackiness of the surface coating.
• U.S. 4,686,118 discloses an ink receiving layer comprising a mixture of a polymer capable of forming intermolecular hydrogen bonds and a polymer incapable of forming intermolecular hydrogen bonds.
• An ink permeable layer is also provided which contains polymers formed from acrylic acid ester, polymers formed from vinyl acetate, vinyl chloride or other hydrophilic vinyl monomers and cellulose derivatives.
• JP 61 193,879 discloses a recording sheet consisting of a film containing a mixture of polyvinyl pyrrolidone and a water-soluble cellulose on a transparent support. These coatings have a tendency to be too water-soluble and not dry well.
• the present invention provides an improved recording sheet having excellent coatability and water-fastness, which exhibits fast drying time and provides images having high print quality in demanding applications wherein high levels of inks are applied to the sheet. Accordingly, the invention provides a recording sheet that bears a coating containing:
• the coating has superior durability by including a reactive species that hardens the coating, after printing, through exposure to heat, light, or other activating energy.
• the coating composition contains a blend of (a) a water-soluble vinyl polymer, (b) an acrylic or methacrylic polymer having a number average molecular weight of at least 10,000, and (c) a water-soluble cellulose compound.
• the composition provides superior performance compared to compositions containing a single component, or blends of only two components. Without the acrylic or methacrylic polymer, the composition is too water receptive, dries poorly, has poor water fastness and handleability. Drying is improved, and tackiness of the coating is decreased, through the presence of the water-soluble cellulose compound.
• the water-soluble vinyl polymer improves drying, print quality, and coatability.
• the composition may contain fillers, additives, and a "reactive species" as described below.
• the vinyl polymers that are selected in practicing the invention are water-soluble.
• Some suitable water-soluble vinyl polymers include polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl alcohol copolymers such as poly(vinyl alcohol-co-vinyl acetate) commonly known as partially hydrolyzed poly(vinyl alcohol), vinyl pyrrolidone copolymers such as poly(vinyl pyrrolidone-co-vinyl acetate), polyvinylpyridinium halide, polyvinylmethylethers, and blends thereof.
• the vinyl polymer may have molecular weight in the range of 10,000 to 1,000,000. Vinyl polymers having molecular weights in excess of about 100,000 are generally preferred.
• the water-soluble vinyl polymers may be present in the amount of 15 to 80 % by weight, preferably 50 to 70 % by weight, based the weight of the total coating composition.
• the acrylic or methacrylic polymer component of the coating has a molecular weight of at least 10,000, and may be a homopolymer, a copolymer, or mixtures thereof.
• Suitable monomeric components of such polymers include acrylic acid, methacrylic acid, lower alkyl of 1 to 6 carbon atoms acrylate esters, lower alkyl of 1 to 6 carbon atoms methacrylate esters, styrene, dialkylamino acrylates and dialkylamino methacrylates.
• a particularly suitable ink absorbent resin contains free carboxylic acid groups, and has an acid number (mg KOH per g) not exceeding 150, and preferably of from 20 to 120; for example, a copolymer of methacrylic acid and methylmethacrylate with an acid number (mg KOH per g) of from about 60 to 100, particularly about 80.
• the acrylic or methacrylic polymer component contains hydroxylic functionality.
• the acrylic or methacrylic polymer may be a super absorbent polymer where the acrylic or methacrylic polymer is modified to the salt form of the carboxylates or sulfonates.
• An example of a super absorbent polymer is Abcote® 56220 sold by Morton Company.
• Acrylic or methacrylic polymers include methyl methacrylate(37%)/ethyl acrylate(56%)/acrylic acid(7%) terpolymer, acid no. 76-85, molecular weight 260,000; methyl methacrylate(61.75%)/ethyl acrylate(25.75%)/acrylic acid(12.5%) terpolymer, acid no. 100, molecular weight 200,000; etc.
• An acrylic polymer containing alkylaminoethylmethacrylate such as a copolymer of butyl methacrylate/dimethylaminoethyl methacrylate, (80/20), average molecular weight 11,000, may be used to advantage.
• the acrylic or methacrylic polymer may be present in the amount of 5 to 70 % by weight, preferably 10 to 30 % by weight based on the total composition.
• the water-soluble cellulose compound is a compound on which water solubility is conferred by replacement of -OH groups in the cellulose.
• the water-soluble cellulose compound may be an alkyl cellulose, cyanoalkyl cellulose, carboxalkyl cellulose, carboxyalkyhydroxyalkyl cellulose, hydroxyalkyl cellulose, hydroxyalkylmethyl cellulose wherein the alkyl is 1 to 4 carbon atoms, and cellulose esters which are made soluble by making the salt of the acid or hydroxy groups, eg. partial esters.
• Representative water-soluble cellulose compounds include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and methylhydroxypropyl cellulose.
• the water-soluble cellulose compound may be present in the amount of 5 to 50 % by weight, preferably 10 to 30 % by weight based on the total composition.
• the filler component if used, is generally an inorganic pigment such as silica, various silicates, zeolites, calcined kaolins, diatomaceous earths, barium sulfate, aluminum hydroxides, calcium carbonate, or the like.
• the coatable film layer can contain other additives.
• surfactants such as silicone, silicone, silicone, and/or styrene foam, silicone foam, and/or silicone foam.
• plasticizers such as silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils, silicone oils
• the coating preferably contains at least one "reactive species" that improves durability, water-fastness, and smear-resistance of non-imaged as well as imaged areas of the printed medium upon exposure to an external energy source after the printing operation.
• the reactive species causes reaction of components in the coating and/or applied ink upon exposure to actinic radiation (preferably UV light), heat, or chemicals to cause the coating to become more durable and less receptive to water.
• the reactive species may contain reactive acid groups, base groups, epoxy groups, styryl-pyridinium groups, styryl-pyrollium groups, dimethylmaleimide groups, cinnamic groups, unsaturated acrylic groups, and bis-azides that react with other groups present in the coating and/or in the ink.
• Catalysts may be included to initiate or accelerate reactions, provided that the catalyst does not prematurely initiate the reaction during the printing operation.
• UV initiators may be employed to advantage to generate the reactive species, such as free radicals or strong acids, for particular applications.
• Heat may be used to produce the reactive species; for example, epoxy groups may require heat to activate crosslinking.
• Reactive species may be used in combination with multivalent metal salts such as calcium, magnesium, zinc and aluminum to generate a chemical reaction with the coating components.
• water-soluble polymers such as polyvinyl alcohol
• pendant photocrosslinkable groups may be used to advantage in the coatable film layer. On exposure these groups react to form crosslinks between different polymer chains.
• photocrosslinkable polymers are described in A. Reiser, Photoreactive Polymers: The Science and Technology of Resists , Wiley, New York, 1989, pp 24-32.
• Typical photocrosslinkable groups are the cinnamyl, chalcone, alpha -phenylmaleimide, N-alkyl styrylpyridinium, and N-alkyl styrylquinolinium groups.
• polyvinyl alcohol having photocrosslinkable groups are preferred.
• Preferred polyvinyl alcohol derivatives have N-alkyl styrylpyridinium or N-alkyl styrylquinolinium groups.
• Such polymers are described in K. Ichimura and S. Wantanabe, J. Polym. Sci. , Polym. Lett. Ed. , 18 , 613 (1980) and 20 , 1411, 1419 (1982) as well as in Ichimura, U.S. Patents: 4,272,620, 4,287,335, 4,339,524, 4,564,580 and 4,777,114.
• Substituted hydrophilic polyvinyl alcohol polymers typically are prepared by derivatization of saponified polyvinyl acetate with the appropriate photo-crosslinking group. It is desirable for the polyvinyl acetate to be at least 70% hydrolyzed. Typically 88% saponified polyvinyl acetate is used, but polyvinyl acetate which is more or less highly saponified can be used.
• the photocrosslinkable group can be attached to the polyvinyl alcohol by any appropriate chemical linkage, such as an ester, ether, or acetal linkage. The acetal linkage is preferred. Typically, 0.5-10 mol% photocrosslinkable groups, preferably 1-4 mol%, are present.
• the degree of polymerization of the polyvinyl alcohol is advantageously in the range of 400 to 3,000.
• the exposure time required for loss of hydrophilic character is lengthened.
• the polymerization degree is too large, the viscosity of solutions containing the polymer becomes so large that they are difficult to prepare and handle.
• Styrylpyridinium or styrylquinolinium acrylates or methacrylates which may be used as the acrylate or methacrylate polymer are prepared as described in U.S. 4,272,620 using hydroxy containing acrylates or methacrylates instead of polyvinyl alcohol.
• bis-azides Another useful class of polyfunctional photoactivatable crosslinking agents are bis-azides. These compounds typically are aromatic bis-azides substituted with one or more ionic groups, such as sulfonate, carboxylate, sulfate, etc., to increase water solubility.
• Representative bis-azides are sodium 4,4'-diazidostilbene-2,2'-disulfonate, sodium 4,4'-diazidobenzalacetophenone-2-sulfonate, and sodium 4,4'-diazidostilbene- alpha -carboxylate.
• a preferred bis-azide is sodium 4,4'-diazidostilbene-2,2'-disulfonate.
• Loss of hydrophilic character is generally achieved by photoinitiated polymerization and/or crosslinking reactions.
• the amount of reactive species included in the coating composition will vary with the particular components of the composition, and the mechanism of activation, and can readily be determined by routine experimentation.
• the support i.e., substrate
• the support may be any of those commonly used in printing.
• cellulose and non-cellulose type substrates may be used to advantage, with porous cellulose type substrates, such as paper, being preferred.
• the degree of sizing for the substrate can be from 1 second to 1000 seconds as measured by the Hercules size test (HST), as described in TAPPI standards T530 PM-83.
• HST Hercules size test
• the substrate is chosen so its HST value is compatible with the volume and composition of the ink drop in the printer to be used.
• the preferred HST is in the range of 200 to 500 seconds, most preferably 350 to 400 seconds.
• Some useful papers are copier grade paper, 100% bleached kraft composed of a blend of hard and soft wood, 100% wood free cotton vellum, and wood containing paper made translucent either by pulp beating or with additives.
• a preferred paper is Gilbert Bond paper (25% cotton) designated style 1057, manufactured by Mead Company, Dayton, OH.
• Standard resin coated papers used in the photographic industry such as polyclad papers, preferably polyethylene clad papers, also may be selected to advantage.
• Some illustrative examples of support for ink jet transparencies which are non-porous and usually have a thickness of about 50 to 125 microns (preferably from about 100 to about 125 microns), include polyester films such as Mylar® flexible film, commercially available from E. I. du Pont de Nemours and Company, Wilmington, DE; Melinex® film, commercially available from Imperial Chemicals, Inc.; Celanar® film, commercially available from Celanese Corp.; polycarbonates such as Lexan® sheet film, commercially available from The General Electric Company, Fairfield, CT; polysulfones, cellulose triacetate; polyvinylchlorides; and the like.
• Mylar® polyester film is preferred because of its availability and low cost.
• Coated transparent films such as gel subbed polyester films, or polyester films with white opaque coatings on them used as proofing receptors, are also useful in practicing the invention.
• the surface coating is applied to the sheet support surface at a dry coating weight of greater than 40 mg/dM2, preferably 90-150 mg/dM2 using conventional coating methods.
• Suitable coating methods include, for example, conventional roller coating or knife coating methods, trailing blade, and the like.
• Culminal® MHPC-25 (Aqualon, Wilmington, De) was slurried with 6 times its weight in water at 50-60°C. Cold water was then added to give a 5% solution.
• PVP K-30 International Specialty Polymers, Wayne, N.J. was dissolved in cold water to give a 6% solution.
• Example 1 is repeated with the following exception: polyvinyl alcohol (PVA) was used in place of PVP K-30.
• PVA polyvinyl alcohol
• the PVA has a viscosity of 28-32 as a 4% solution, and a mole % degree of hydrolysis of 99 to 99.8.
• the solution is made as described in Example 1 of U.S. 5,141,797.
• Example 1 is repeated with the following exception: styrylpyridinium acrylate is used as the acrylate polymer. It is prepared by reacting styrylpyridinium aldehyde with a copolymer of methyl methacrylate/hydroxyethyl methacrylate (60/40), average molecular weight of 12,000, as described in U.S. 4,272,620. After printing with an ink jet ink prepared as described in U.S. 5, 085,698, the resulting printed recording sheet is UV cured in a Cyrel® 1215 exposure unit (E.I.
• Example 1 is repeated with the following exceptions: SPP 11-KM which is polyvinyl alcohol acetalized with N-methyl-4-(p-formystyryl)pyridinium methosulfate; Toyo Gosei Kogyo Company, Ltd., Ichikawa City, Chiba Pref., Japan is used as the vinyl polymer. A copolymer of butyl methacrylate/dimethylaminoethyl methacrylate (80/20) having an average molecular weight of 11,000, and 90% neutralized with acetic acid is used as the acrylic polymer.
• the recording sheet is printed with an ink jet ink and UV cured as described in Example 6, and would be expected to give similar results.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=22754119

Family Applications (1)

Country Status (3)

Cited By (9)

Families Citing this family (2)

Citations (2)

Family Cites Families (5)

• 1995
  • 1995-02-03 EP EP95101463A patent/EP0672537A1/de not_active Withdrawn
  • 1995-02-03 SG SG9608215A patent/SG80547A1/en unknown
  • 1995-02-27 JP JP7038013A patent/JPH07257023A/ja active Pending

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events