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
  • B41M5/502—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording characterised by structural details, e.g. multilayer materials
  • B41M5/504—Backcoats
• • 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
  • B41M5/502—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording characterised by structural details, e.g. multilayer materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/50—Recording sheets characterised by the coating used to improve ink, dye or pigment receptivity, e.g. for ink-jet or thermal dye transfer recording
  • B41M5/52—Macromolecular coatings
  • B41M5/5218—Macromolecular coatings characterised by inorganic additives, e.g. pigments, clays

Definitions

• the present invention relates to recording materials for ink-jet printing, which are characterized in that on one side of a porous support at least one ink receiving layer consisting of nanoporous, fumed silica with a positively charged surface and at least one binder and on the other side of the carrier Have polyolefin layer.
• ink jet printing There are essentially two different methods of ink jet printing, namely, continuous and non-continuous ink jet printing.
• continuous ink-jet printing an ink jet is ejected under pressure from a nozzle, which drops into individual droplets at a certain distance from the nozzle.
• the individual droplets are, depending on whether an image location is to be printed or not, deflected into a collection container or applied to the recording material. This happens, for example, in that, on the basis of predetermined digital data, unneeded droplets are electrically charged and subsequently deflected into the collecting container in a static electric field.
• the reverse procedure is also possible in which uncharged droplets are collected in the collecting container.
• the so-called "drop on demand” the ink droplets are only generated and expelled from the nozzle when a pixel has to be displayed on the basis of the digital data.
• Today's inkjet printers must be able to print faster and faster for economic reasons.
• suitable recording materials must therefore be able to record the inks very quickly.
• recording materials which contain nanoporous inorganic compounds, preferably oxides, in particular aluminum oxides or silicon dioxide, or oxide / hydroxides, in particular aluminum oxide / hydroxides. Such materials are known as “nanoporous" recording materials.
• Nanoporous recording materials which contain pyrogenic silicon dioxide with a positively charged surface as nanoporous, inorganic oxide are particularly preferred.
• Nanoporous recording materials absorb the inks very quickly (in the microsecond range) due to the capillary forces of the nanoporous compounds.
• Polymer-based recording materials take the inks more slowly (in the millisecond range) by the swelling of the polymer.
• Recording materials on porous paper supports absorb the inks at comparable speed by swelling the paper felt.
• the patent application DE 10'020'346 proposes a recording material for ink-jet printing which contains in the ink receiving layer gaseous phase-produced silica having a primary particle size of at most 20 nm, wherein the surface of the silica was obtained by treatment with polyaluminum hydroxychloride.
• the ink-receiving layer contains gas-phase-produced silica whose surface has been modified with aluminum chlorohydrate. This surface is positively charged.
• the aim of the invention is to provide nanoporous recording materials with reduced thickness of the ink-receiving layer, which show a good flatness.
• Another object of the invention is to provide such nanoporous recording materials with reduced dye diffusion and improved coalescence (no puddling of the inks in printing).
• a paper support coated only on the backside with polyolefins Such a recording material according to the invention consists of a porous paper support to which at least one ink receiving layer consisting of nanoporous, fumed silica having a positively charged surface and at least one binder has been applied to the front side and a polyolefin layer has been applied to the backside.
• a nanoporous recording material for inkjet printing comprising at least one ink receiving layer consisting of nanoporous fumed silica having a positively charged surface and at least one binder on the front side of a porous paper support and a polyolefin layer on the back side, substantially better flatness than a corresponding recording material whose porous paper backing has no polyolefin layer on the back.
• the thickness of the ink receiving layer on the front side can be substantially reduced and the inventive recording material still has the required high ink absorption speed and the required high ink absorption capacity.
• the dye diffusion is also substantially improved in such novel recording methods.
• the porous paper backing having a polyolefin back layer used does not contain a polyolefin layer nor a subbing layer on the ink receiving layer side, but a thin layer of calcium carbonate, preferably together with a binder, especially starch.
• the paper felt of the carrier has a thickness between 100 .mu.m and 250 .mu.m, preferred for the novel recording materials is a thickness between 150 .mu.m and 200 .mu.m.
• One or more polyolefin layers of different composition can be applied to the back side of this paper carrier. It can be used in their properties different polyolefins. Particularly preferred are mixtures of high density polyethylene (HDPE) and low density polyethylene (LDPE).
• Low density polyethylene is characterized by a softening point of about 130 ° C to about 170 ° C and a density of 0.92 g / cm 3 . It is soft and very flexible.
• High Density Polyethylene is characterized by a softening point of about 110 ° C to about 140 ° C and a density of about 0.94 g / cm 3 to a maximum of 0.97 g / cm 3 . It is stiffer and more abrasion resistant than LDPE.
• the backing layer may be pure HDPE, a blend of HDPE and LDPE, or pure LDPE. Preference is given to backing layers which contain at least 20% by weight of LDPE.
• the application rate of the polyethylene is preferably between 5 g / m 2 and 30 g / m 2 , more preferably the range between 7 g / m 2 and 25 g / m 2 .
• the dispersions of the surface-modified fumed silica can be prepared as described in the aforementioned patents DE 10'020'346 . WO 00 / 20,221 and WO 02 / 094,573 getting produced.
• the surface modification of the fumed silica can be carried out by reaction with a compound of trivalent aluminum, preferably with aluminum chlorohydrate, or by the reaction with an aminoorganosilane.
• fumed silica is added at high shear rates to a mainly water-containing solution containing the reaction products of a compound of trivalent aluminum (for example, aluminum chlorohydrate) and at least one aminoorganosilane. This produces under suitable conditions, a surface-modified dispersion of fumed silica, which does not coagulate.
• a compound of trivalent aluminum for example, aluminum chlorohydrate
• the mixture containing the reaction products of a compound of trivalent aluminum (for example, aluminum chlorohydrate) and at least one aminoorganosilane exhibits a high buffering capacity.
• the basic aminoorganosilane neutralizes hydrochloric acid formed in the hydrolysis of the compound of trivalent aluminum (for example, aluminum chlorohydrate).
• the minimum amount of trivalent aluminum compound (for example, aluminum chlorohydrate) required for surface modification of the fumed silica is much lower in this process than when reacted with aluminum chlorohydrate.
• the novel surface-modified Dispersions of the fumed silica have a much lower salt content than in the modification with aluminum chlorohydrate.
• Deionized water is preferably used to prepare the water-based solutions.
• the reaction products of a compound of trivalent aluminum (for example, aluminum chlorohydrate) and at least one aminoorganosilane can be prepared both by adding the aminoorganosilane to an aqueous solution of the trivalent aluminum compound (for example, aluminum chlorohydrate) and in the reverse order.
• the reaction of the compound of trivalent silicon and Aminoorganosilans to the reaction products is carried out at temperatures between 10 ° C and 50 ° C for 5 minutes to 60 minutes. Preferably, the reaction is at room temperature for 10 minutes to 15 minutes.
• Si-O-Al bridges are formed, which can be detected by 27 Al nuclear magnetic resonance spectroscopy.
• the nuclear resonance spectrum of the reaction mixture new peaks occur with a signal layer at 50 ppm to 70 ppm, which are characteristic of Si-O-Al bridges. Their intensity increases with the amount of aminoorganosilane.
• the reaction is completed according to nuclear magnetic resonance spectroscopy measurements after about 10 minutes at room temperature.
• the reaction products of a compound of trivalent aluminum (for example aluminum chlorohydrate) and at least one aminoorganosilane may also be added to an aqueous dispersion of pyrogenic silicon dioxide to produce the superficially modified fumed silica.
• the dispersion of the surface-modified fumed silica used in the ink-receiving layer can be advantageously used directly for preparing the coating composition of the ink-receiving layer of the ink-jet recording material of the present invention.
• the nanoporous recording materials according to the invention also contain at least one binder in the ink-receiving layer.
• the binders are generally water-soluble polymers. Particularly preferred are film-forming polymers.
• the water-soluble polymers include, for example, natural or modified compounds prepared therefrom, such as albumin, gelatin, casein, starch, gum arabic, sodium or potassium alginate, hydroxyethyl cellulose, carboxymethyl cellulose, ⁇ -, ⁇ - or ⁇ -cyclodextrin, etc.
• one of the water-soluble polymers is gelatin
• all known types of gelatin can be used, such as sour pork skin gelatin or alkaline bone gelatin, acidic or basic hydrolyzed gelatins, as well as substituted gelatins, for example phthalated, acetylated or carbamoylated gelatin, or trimellitic anhydride reacted gelatin.
• Synthetic binders may also be used and include, for example, polyvinyl alcohol, polyvinylpyrrolidone, fully or partially saponified compounds of copolymers of vinyl acetate and other monomers; Homopolymers or copolymers of unsaturated carboxylic acids such as maleic acid, (meth) acrylic acid, crotonic acid, etc .; Homopolymers or copolymers of sulfonated vinyl monomers such as vinylsulfonic acid, styrenesulfonic acid, etc.
• homopolymers or copolymers of vinyl monomers of (meth) acrylamide Homopolymers or copolymers of other monomers with ethylene oxide; polyurethanes; polyacrylamides; Polyester; polyvinyl lactams; Acrylamide polymers; substituted polyvinyl alcohol; polyvinyl; Polymers of alkyl and sulfoalkyl acrylates and methacrylates; hydrolyzed polyvinyl acetates; polyamides; polyvinylpyridines; polyacrylic acid; Copolymers with maleic anhydride; polyalkylene oxides; Copolymers with methacrylamide and copolymers with maleic acid are used. All of these polymers can also be used as mixtures.
• a preferred synthetic binder is polyvinyl alcohol.
• the degree of hydrolysis of the polyvinyl alcohol is preferably between 85% and 100% and its molecular weight between 14,000 and 205,000. It is also possible to use mixtures of polyvinyl alcohols of different degrees of hydrolysis and / or molecular weights.
• These binders can be mixed with water-insoluble natural or synthetic high molecular compounds, in particular with acrylic latices or styrene acrylic latices. Although water-insoluble binders are not explicitly claimed, water-insoluble polymers should nevertheless be regarded as a system component.
• the above-mentioned polymers having crosslinkable groups can be converted to practically water-insoluble layers with the aid of a crosslinker or hardener.
• crosslinks can be covalent or ionic.
• the crosslinking or curing of the layers allows a change in the physical layer properties, such as the fluid intake, or the resistance to coating injuries.
• the crosslinkers and hardeners are selected on the basis of the water-soluble polymers to be crosslinked.
• Organic crosslinkers and hardeners include, for. B.
• aldehydes such as formaldehyde, glyoxal or glutaraldehyde
• N-methylol compounds such as dimethylolurea or methylol-dimethylhydantoin
• Dioxanes such as 2,3-dihydroxydioxane
• reactive vinyl compounds such as 1,3,5-trisacryloyl-hexahydro-s-triazine or bis (vinylsulfonyl) ethyl ether
• reactive halogen compounds such as 2,4-dichloro-6-hydroxy-s-triazine
• epoxides aziridines
• CarbamoylpyridinENSen or mixtures of two or more of these crosslinkers mentioned.
• Inorganic crosslinkers and hardeners include, for example, chrome alum, aluminum alum or preferably boric acid.
• the layers may also contain reactive substances which crosslink the layers under the influence of UV light, electron beams, X-ray
• the layers can be further modified by the addition of fillers.
• Fillers are z. As kaolin, Ca or Ba carbonates, silica, titania, bentonites, zeolites, aluminum silicate or calcium silicate. Also, inert organic particles such as plastic beads can be used. These beads may consist of polyacrylates, polyacrylamides, polystyrene or various copolymers of acrylates and styrene.
• the fillers are selected based on the intended use of the images produced. Some of these fillers can not be used in transparent materials. But they can have positive effects in supervisory materials. Very often one achieves a desired matt surface with the use of such fillers.
• at least one ink-receiving layer, together with any auxiliary layers, is applied to a support.
• the ink receiving layers of this invention are generally cast from aqueous solutions or dispersions containing all the necessary components.
• wetting agents are added as Begussangesmittel to improve the casting behavior and the layer uniformity.
• these compounds can also have an influence on the image quality and can therefore be selected accordingly.
• surface-active compounds are not claimed in the invention, they nevertheless form an integral part of the invention.
• the novel recording materials may contain additional compounds in order to further improve its properties, for example optical brighteners Improving the degree of whiteness, such as stilbenes, coumarins, triazines, oxazoles or other compounds known in the art.
• UV absorbers such as 2-hydroxybenzotriazoles, 2-hydroxybenzophenones, triazine derivatives or cinnamic acid derivatives.
• the amount of UV absorber is 200 mg / m 2 to 2000 mg / m 2 , preferably 400 mg / m 2 to 1000 mg / m 2 .
• the UV absorber may be incorporated in any layer of the recording material of the invention, but it is particularly advantageous if it is introduced into the uppermost layer. It is further known that the images prepared in ink-jet printing can be protected by the addition of radical scavengers, stabilizers, reducing agents and antioxidants.
• Examples of such compounds are sterically hindered phenols, sterically hindered amines, chromanols, ascorbic acid, phosphinic acids and their derivatives, sulfur-containing compounds such as sulfides, mercaptans, thiocyanates, thioamides or thioureas.
• the compounds mentioned can be added as aqueous solutions to the casting solutions. If the compounds are not sufficiently soluble in water, they may be incorporated into the casting solutions by other known methods. Thus, for example, the compounds can be dissolved in a water-miscible organic solvent such as lower alcohols, glycols, ketones, esters or amides. It is also possible to incorporate the compounds as fine-grained dispersions, as oil emulsions, as cyclodextran inclusion compounds or as latex containing the compound in the casting solution.
• the ink receiving layer of the novel recording material has a dry film thickness between 0.5 ⁇ m and 100 ⁇ m, but in particular between 10 ⁇ m and 25 ⁇ m.
• the casting solutions can be applied to the carrier in various ways.
• the casting processes include, for example, extrusion casting, air knife casting, slot casting, cascade casting and curtain casting.
• the casting solutions can also be applied by a spray process.
• the ink receiving layers may consist of a plurality of individual layers, which may be applied one by one or in common. However, the chosen casting method does not limit the invention in any way.
• Inkjet printing inks consist essentially of a liquid vehicle and a dye or pigment dissolved or dispersed therein.
• the liquid carrier for inkjet inks is generally Water or a mixture of water and a water-miscible solvent such as ethylene glycol, higher molecular weight glycols, glycerol, dipropylene glycol, polyethylene glycol, amides, polyvinylpyrrolidone, N-methylpyrrolidone, cyclohexylpyrrolidone, carboxylic acids and their esters, ethers, alcohols, organic sulfoxides, sulfolane, Dimethylformamide, dimethylsulfoxide, cellosolve, polyurethanes and acrylates.
• the non-aqueous ink components generally serve as humectants, co-solvents, viscosity modifiers, penetrants or drying accelerators.
• the organic compounds usually have a boiling point that is higher than that of water.
• the dyes or pigments that can be used to prepare inks useful with the inventive recording materials contain virtually all known classes of these colored compounds. Typical examples of dyes or pigment used are in the patent application EP 0'559'324 listed.
• the recording materials according to the invention can be used with almost all prior art inks.
• the inks may contain other additives such as surfactants, optical brighteners, UV absorbers, light stabilizers, preservatives, precipitants such as multi-charged metal compounds, and polymeric compounds.
• additives such as surfactants, optical brighteners, UV absorbers, light stabilizers, preservatives, precipitants such as multi-charged metal compounds, and polymeric compounds.
• the recording materials according to the invention are examined for their flatness (Edge Lift Curl) according to the test method described by ANSI (American National Standard Institute) ( ANSI IT9.10-1991, Test Method C, page 3, 1991 ).
• sheets of the format DIN A4 of the novel recording material are conditioned for 24 hours under the temperature and humidity conditions defined in the standard and then placed on a flat surface with the concave side upwards. Then, the distance between the flat surface and the 4 corners of the recording material is measured. The values given in the table represent this Deviations from the flatness of the 4 corners of a sheet.
• Deviations from the flatness to the side of the ink receiving layer are marked with a positive sign and referred to as a positive edge lift curl.
• Deviations of the flatness to the ink receiving layer side facing away are marked with a negative sign and referred to as a negative edge lift curl.
• the printed recording materials are dried for 24 hours at a temperature of 23 ° C at a relative humidity of 50%. Subsequently, the optical densities of the color fields are determined. Subsequently, the printed recording materials are stored for 7 days at a temperature of 40 ° C and a relative humidity of 80%, and the optical densities are measured again.
• the value of dye diffusion is the percentage difference in optical densities before and after storage of the color field with the greatest density difference.
• Coalescence refers to the puddle-like convergence of ink during printing.
• Table 1 100% teal 60% purple, 60% yellow 100% purple 60% teal, 60% yellow 100% yellow 60% teal, 60% purple 100% teal 55% purple, 55% yellow 100% purple 55% teal, 55% yellow 100% yellow 55% teal, 55% purple 100% teal 50% purple, 50% yellow 100% purple 50% teal, 50% yellow 100% yellow 50% teal, 50% purple 100% teal 45% purple, 45% yellow 100% purple 45% teal, 45% yellow 100% yellow 45% teal, 45% purple 100% teal 40% purple, 40% yellow 100% purple 40% teal, 40% yellow 100% yellow 40% teal, 40% purple 100% teal 35% purple, 35% yellow 100% purple 35% teal, 35% yellow 100% yellow 35% teal, 35% purple 100% teal 30% purple, 30% yellow 100% purple 30% teal, 30% yellow 100% yellow 30% teal, 30% purple 100% teal 25% purple, 25% yellow 100% purple 25% teal, 25% yellow 100% yellow 25% teal, 25% purple 100% teal 20% purple, 20% yellow 100% purple 20% teal, 20% yellow 100% purple 20% teal, 20% yellow 100% yellow 20% teal, 20% yellow 100% yellow 20% teal, 20% purple 90% tea
• the dispersion After completion of the addition of the fumed silica, the dispersion is stirred for 15 minutes with a rotor-stator mixer. Subsequently, the dispersion is heated to a temperature of 60 ° C and held for surface modification of the silica for 1 hour at this temperature.
• the polyethylene amounts of the backside coating of the paper support are summarized in Table 2: Table 2 example HDPE (g / m 2 ) LDPE (g / m 2 ) 1 15 5 2 10 10 3 5 15 4 0 20
• 158 g / m 2 of the casting solution from Examples 1 - 4 are applied at a temperature of 40 ° C by means of a bar coater on a paper support with a thickness of the paper felt of 190 microns, which is coated on both sides with polyethylene. Subsequently, the coated carrier is dried for 60 minutes at a temperature of 35 ° C. 1 m 2 of the dried recording material contains 19 g of the unmodified fumed silica used.
• This comparative example corresponds to Comparative Example C-2, with the difference that the application rate of the casting solution is reduced from 158 g / m 2 to 108 g / m 2 . 1 m 2 of the dried recording material contains 13 g of the unmodified fumed silica used.
• Example 4 shows that the ink jet recording material of the present invention (Example 1) has substantially less dye diffusion than the ink jet recording material on one non-porous paper support coated on both sides with polyethylene (Comparative Example C-3), although Comparative Example C-3 has a substantially thicker ink-receiving layer than the recording material of the present invention.
• the surface modification of the fumed silica was carried out with the reaction products of the aluminum salt Locron P and the aminoorganosilane N- (2-aminoethyl) -3-aminopropyltrimethoxysilane.
• novel recording materials also show a substantially lower dye diffusion than the two commercially available nanoporous recording materials ILFORD Smooth Gloss (which contains lanthanum-doped colloidal alumina / hydroxide as a nanocrystalline, nanoporous compound) and Mitsubishi SG 2575 (which contains colloidal silica as a nanoporous compound).
• ILFORD Smooth Gloss which contains lanthanum-doped colloidal alumina / hydroxide as a nanocrystalline, nanoporous compound
• Mitsubishi SG 2575 which contains colloidal silica as a nanoporous compound

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Ink Jet Recording Methods And Recording Media Thereof (AREA)
• Ink Jet (AREA)
• Laminated Bodies (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)

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• 2005
  • 2005-05-25 AT AT05104489T patent/ATE419126T1/de not_active IP Right Cessation
  • 2005-05-25 EP EP05104489A patent/EP1726448B1/fr not_active Not-in-force
  • 2005-05-25 DE DE502005006379T patent/DE502005006379D1/de active Active
• 2006
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  • 2006-05-18 JP JP2006138483A patent/JP2006327194A/ja active Pending
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