JP4503984B2 - Inkjet recording element - Google Patents

Description

  The present invention relates to a porous ink jet recording element containing two types of polymer particles.

  In a typical ink jet recording system or ink jet printing system, ink droplets are ejected from a nozzle at high speed toward a recording element or recording medium, producing an image on the medium. Ink droplets (or recording liquids) generally comprise a recording agent (eg, a dye or pigment) and a large amount of solvent. The solvent (or carrier liquid) is generally made from water and organic materials (eg, monohydric alcohols, polyhydric alcohols, or mixtures thereof).

  Ink jet recording elements generally comprise a support carrying an ink-receiving layer or an image-receiving layer on at least one surface, such elements having an opaque support for reflective viewing. Those intended and those intended for observation by transmitted light having a transparent support are included.

  An important property of ink jet recording elements is that they need to dry quickly after printing. To this end, porous recording elements have been developed that provide near instantaneous drying as long as they have sufficient thickness and pore volume to effectively contain liquid ink. For example, a porous recording element can be produced by a cast coating in which a particulate-containing coating is applied to a support and dried in contact with a polished smooth surface.

  Ink jet prints prepared by printing on an ink jet recording element are susceptible to environmental degradation. They are particularly vulnerable to damage resulting from contact with atmospheric gases such as water and ozone. Damage due to contact with water after this imaging is due to water spots due to loss of gloss in the topcoat, dye smearing due to undesired dye diffusion, and to the entire image recording layer. Sometimes it takes the form of dissolution. Ozone bleaches inkjet dyes and loses density. In order to overcome these deficiencies, inkjet prints are often laminated. However, lamination is expensive because it requires a release roll of material. Print protection can also be provided by applying a polymer solution or dispersion on the surface of the inkjet element after the image is formed. Aqueous coating solutions are often polymer dispersions that are capable of forming a film when water is removed. However, due to the wide variety of surface properties, it is difficult to formulate an aqueous polymer solution to be universally compatible with all inkjet receivers.

  Instead, an ink jet recording element having a two-layer structure (e.g. described in EP 1 078 775, JP 59-222,381 and US Pat. No. 4,832,984) Has been used. These elements generally have a porous ink transport topcoat of heat fusible particles that resides on either a swellable or porous ink retaining layer. During printing, the ink passes through the top coat and proceeds into the ink holding layer. The topcoat layer is then sealed to provide a print that is water and stain resistant. Such topcoats containing thermofusible particles are generally either binder-containing or thermally sintered, thus, the imaging process and Prior to the fusing process, a certain degree of mechanical integrity is provided to the layers.

  Japanese Patent Application Laid-Open No. 56-99,694 discloses an ink jet recording element in which an image receiving layer contains latex or wax particles having a diameter of 0.1 to 5.0 μm. The recording element has a porous surface and the image-receiving layer has very poor bonding properties and the support tends to cause dusting that results in image defects.

  In EP 0 858 905, a particulate thermoplastic resin is applied and dried at a temperature higher than its glass transition temperature (Tg) but lower than its minimum film forming temperature (MFFT). Discloses the preparation of a recording medium comprising a porous outermost layer. However, this element is problematic in that the drying temperature must be controlled very precisely between the Tg and the MFFT in order to achieve the desired result.

  EP-A-0 858 906 relates to a base material having a good ink capacity, a porous ink receiving layer, and a porous surface layer. However, it is desirable to obtain good ink capacity without the need to use a separate ink receiving layer.

  Prior art document information related to the invention of this application includes the following.

U.S. Pat.No. 4,832,984 U.S. Patent No. 6,399,156 European Patent Application Publication No. 1 078 775 European Patent Application Publication No. 0 858 905 JP 59-222,381

  It is an object of the present invention to provide a novel porous inkjet recording element that instantly absorbs ink and provides an image with good quality, water resistance and abrasion resistance after imaging. . Another object of the present invention is to provide a porous inkjet recording element that is easy to manufacture.

  These and other objects are ink jet recording elements comprising a support carrying a fusible porous image-receiving layer comprising at least two types of hydrophobic polymer particles having different glass transition temperatures. Wherein the first type of hydrophobic polymer particles that are substantially monodisperse have a Tg greater than about 60 ° C, and the second type of hydrophobic polymer particles have a Tg of less than about 25 ° C. This is achieved by the present invention comprising an inkjet recording element.

  By using the present invention, when printed with inkjet ink, it becomes “instantly” dry to the touch, has good image quality, and has sufficient wear and water resistance after fusing. A porous ink jet recording element is obtained.

  The element of the present invention is particularly suitable for inkjet transmissive media and medical imaging media, since there is nothing to scatter light in the ink-receiving layer after fusing.

  The substantially monodisperse first type of hydrophobic polymer particles used in the present invention are, for example, emulsion polymerization of ethylenically unsaturated monomers with or without a surfactant. Can be prepared. Any suitable ethylenically unsaturated monomer or mixture of monomers may be used in the production of monodisperse polymer particles. For example, ethylene, propylene, 1-butene, butadiene, styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, monoethylenically unsaturated esters of fatty acids (for example, vinyl acetate, Allyl acetate, vinyl stearate, vinyl pivalate), monoethylenically unsaturated amides of fatty acids (eg N-vinylacetamide, N-vinylpyrrolidone), esters of ethylenically unsaturated monocarboxylic acids or dicarboxylic acids (eg acrylics) Methyl acid, ethyl acrylate, propyl acrylate, 2-chloroethyl acrylate, 2-cyanoethyl acrylate, hydroxyethyl acrylate, methyl methacrylate, n-butyl methacrylate, benzyl acrylate, 2-ethylhexyl acrylate, methacrylic acid Cyclohexyl, acrylic acid Trahydrofurfuryl, tetrahydrofurfuryl methacrylate, isobornyl acrylate, isobornyl methacrylate, n-octyl acrylate, diethyl maleate, diethyl itaconate), ethylenically unsaturated monocarboxylic amides (eg acrylamide, t-butyl) Acrylamide, isobutyl acrylamide, n-propyl acrylamide, dimethyl acrylamide, methacrylamide, diacetone acrylamide, acryloylmorpholine), and mixtures thereof. The stability of the particles may be improved by copolymerizing 5% by weight or less of a water-soluble monomer with respect to the total monomer mixture. Examples of preferred water-soluble comonomers include ethylenically unsaturated salts of sulfonic acid or sulfuric acid (eg sodium acrylamide-2-methylpropane-sulfonate, sodium vinylbenzenesulfonate, potassium vinylbenzylsulfonate, sodium vinylsulfonate) , Monoethylenically unsaturated compounds (for example, acrylonitrile, methacrylonitrile), and monoethylenically unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid).

  If desired, monomers containing UV-absorbing moieties, antioxidant moieties, or crosslinking moieties can be used in forming the monodisperse polymer particles to improve light fastness or other performance of the image. May be. Examples of UV absorbing monomers that can be used include:

  Typical crosslinking monomers that can be used in forming the monodisperse polymer particles used in the present invention include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, or derivatives thereof), esters of diethylene carboxylic acid. And amides (eg, ethylene glycol dimethacrylate, ethylene glycol diacrylate), and other divinyl compounds (eg, divinyl sulfide compounds or divinyl sulfone compounds). Divinylbenzene and ethylene glycol dimethacrylate are particularly preferred.

  Examples of the preparation of monodisperse polymer particles can be found in “Emulsion Polymerization and Emulsion Polymers”, PA Lovell and MS El-Aasser, John Wiley & Sons, Ltd., 1997, and US Pat. No. 4,415,700 ( These disclosures are incorporated herein by reference).

  The monodisperse polymer particles used in the present invention are non-porous. Non-porous means particles that are free of voids or not permeable to liquids. These particles may have a smooth surface or a rough surface.

  The second type of hydrophobic polymer used in the present invention having a Tg of less than 25 ° C. may be a latex or hydrophobic polymer of any composition that can be stabilized in an aqueous medium. . Such hydrophobic polymers are generally classified as either condensation polymers or addition polymers. Condensation polymers include, for example, polymers comprising polyesters, polyamides, polyurethanes, polyureas, polyethers, polycarbonates, polyanhydrides, and combinations of the types described above. The addition polymer is a polymer formed by polymerization of vinyl type monomers described above for the preparation of monodisperse polymer particles. Polymers comprising monomers that form water-insoluble homopolymers are preferred, and copolymers of such monomers are also preferred. Preferred polymers may also comprise monomers that yield water-soluble homopolymers if the overall polymer composition is sufficiently water insoluble to form a latex. The aqueous phase of the latex or colloidal dispersion of the present invention may contain a water-soluble polymer, for example, to control viscosity and fluidity. The aqueous phase may also contain cationic, anionic, zwitterionic or nonionic surfactants. A further list of suitable monomers for addition type polymers is found in US Pat. No. 5,594,047, the disclosure of which is hereby incorporated by reference.

  In a preferred embodiment of the invention, the Tg of the first type of polymer particles is from about 60 ° C to about 140 ° C. In another embodiment, the Tg of the second type of hydrophobic polymer is from about −60 ° C. to about 25 ° C. In yet another preferred embodiment, the monodisperse polymer particles having a Tg of about 60 ° C. to about 140 ° C. have an average particle size of about 0.2 μm to about 2 μm. This average particle size is defined as the size (or diameter) at which 50% by volume of the particles are smaller.

  In yet another preferred embodiment, the monodisperse polymer particles have a decimal ratio of less than about 2, the decimal ratio being a monodisperse index and the 90th percentile of the particle size distribution curve. Is defined as the ratio of the particle size to the particle size at the 10th percentile. The percentile is defined as a predetermined percentage of capacity that is less than the indicated magnitude. In yet another preferred embodiment, the mass ratio of the high Tg monodisperse polymer particles to the low Tg hydrophobic polymer is from about 10: 1 to about 2.5: 1.

  After printing on the elements used in the present invention, the fusible porous ink receiving layer is fused by heat and / or pressure to form a substantially continuous transparent layer on the surface. Upon fusing, this layer becomes non-light scattering. Fusion may be accomplished by any technique that is effective for the intended purpose. A description of a fusing method using a fusing belt can be found in US Pat. No. 5,258,256, and a description of a fusing method using a fusing roller can be found in US Pat. No. 4,913,991 ( These disclosures are incorporated herein by reference).

  In a preferred embodiment, fusing is accomplished by contacting the surface of the element with a heat fusing member (eg, a fusing roller or fusing belt). Thus, for example, fusing involves heating the element to a temperature of about 60 ° C. to about 160 ° C. using a pressure of 5 to about 15 MPa at a transfer rate of about 0.005 m / min to about 0.5 m / min. Can be achieved by passing it through a pair of heated rollers.

  The image receiving layer may further contain additives such as a pH adjuster, a rheology adjuster, a surfactant, an ultraviolet absorber, a biocide, a lubricant, a wax, a dye, and a fluorescent brightening agent.

  The image receiving layer can be applied to one or both of the substrates by conventional pre-weighing or post-weighing application methods (eg, blade coating, air knife coating, rod coating, roll coating, slot die coating, curtain coating, slide coating, etc.). Can be applied to any surface. The choice of application method depends on the economics of operation, which in turn will determine the formulation specifications such as coating solids, coating viscosity, and coating speed.

The thickness of the image receiving layer prior to fusing can range from about 10 to about 100 μm, preferably from about 20 to about 70 μm. The required coating thickness is determined by the need for the coating to act as a reservoir to absorb the ink solvent. Generally, the image receiving layer is applied in an amount of about 10 g / m ² to about 60 g / m ² . Further, the pore volume of the fusible, porous image-receiving layer is generally from about 5 to about 50 mL / m ^2.

  The support used in the ink jet recording element of the present invention may be opaque, translucent, or transparent. Examples of materials that may be used include plain paper, resin-coated paper, laminated paper (for example, U.S. Patent Nos. 5,853,965, 5,866,282, 5,874,205, 5,888,643, 5,888,681, And those described in, for example, polyester resins (for example, polyethylene terephthalate, polyethylene naphthalate, and polyester diacetate), cellulosic materials (for example, cellulose acetate, cellulose diacetate, And cellulose triacetate), polycarbonate resin, fluororesin (for example, polytetrafluoroethylene), metal foil, and various plastics such as various glass materials. The support may be a polyolefin, polyester, or membrane containing voids. Examples of the preparation of void-containing polyesters can be found in US Pat. Nos. 5,354,601 and 6,379,780. Voided films can be formed by known techniques of phase inversion. The thickness of the support used in the present invention can be 12 to 500 μm, preferably 75 to 300 μm.

  If desired, to improve the adhesion of the porous particle layer of the present invention to the support, the surface of the support is subjected to a corona discharge treatment before the base layer or the solvent absorbing layer is applied to the support. May be.

  Although the recording elements disclosed herein have been mentioned primarily as useful in ink jet printers, they can also be used as recording media for pen plotter assembly devices. Pen plotters operate by writing directly on the surface of a recording medium using a pen consisting of a bundle of capillaries in contact with an ink reservoir.

  In the ink jet printing method, ink droplets are rapidly absorbed into the porous coating by capillary action, and the image is dry to the touch immediately after it exits the printer. Thus, the porous coating allows for fast “drying” of the ink, resulting in an image that is stain resistant.

  Since the image recording element may come into contact with the drive mechanism or transfer mechanism of another image recording article or image recording apparatus, for example, additives such as surfactants, lubricants, matting particles, etc. You may add to the said element to such an extent that an important property is not deteriorated.

  Ink jet inks used to image the recording elements of the present invention are well known in the art. In general, ink compositions used in ink jet printing are liquid compositions comprising a solvent or carrier liquid, a dye or pigment, a wetting agent, an organic solvent, a detergent, a thickener, a preservative, and the like. The solvent or carrier liquid may be just water or water mixed with other water-miscible solvents such as polyhydric alcohols. Further, an ink in which an organic material such as polyhydric alcohol is the main carrier or solvent liquid may be used. Particularly useful is a mixed solvent of water and a polyhydric alcohol. The dyes used in such compositions are generally water-soluble direct dyes or acidic type dyes. Such liquid compositions are extensively described in the prior art such as, for example, U.S. Pat. Nos. 4,381,946, 4,239,543, and 4,781,758, the disclosures of which are hereby incorporated by reference. Incorporated into the book).

  The following examples are provided to illustrate the invention.

Example 1
Preparation of monodisperse polymer particles The particles of the present invention were prepared from one of the three methods shown below.

Method A: Preparation of anionic monodisperse polymer particles in the presence of a surfactant
A 2 liter reaction flask was prepared by adding 753 g demineralized water, 2.56 g Aerosol MA-80 (Cytek Industries, Inc.), and various amounts of sodium carbonate. The contents of these flasks were heated to 80 ° C. with stirring at 150 RPM in a nitrogen atmosphere. An aqueous phase addition flask was prepared using 649 g of demineralized water, 3.38 g of Aerosol MA-80, and 3.78 g of sodium persulfate. A monomer phase addition flask was prepared by adding 1011.4 g of ethyl methacrylate and 164.6 g of methyl methacrylate. Next, 3.43 g of sodium persulfate was added to the reaction flask. Within 2 minutes, 498 g of the aqueous phase and 820 g of the monomer phase were added over 3 hours. The reactor contents were then heated at 80 ° C. for 2 hours, then cooled to 20 ° C. and filtered through 200 μm polycloth. The latex was concentrated to 50% solids by ultrafiltration. The particle size of the latex was controlled by the monomer phase added and the amount of sodium carbonate. The surfactant and initiator concentrations were kept constant at 0.5% and 0.7% by weight, respectively, with respect to the monomer. For example, for 40% reaction solids without sodium carbonate, the median particle size is 517.7 nanometers, and for 50% reaction solids with 7.84 g sodium carbonate, the median particle size is It was 831.6 nanometers. When 800 nanometer particles were desired, it was necessary to supply the monomer phase little by little to avoid the accumulation of monomer and the increase in heat generation. To do this, 507 g of the aqueous phase was charged over 3.5 hours. At the same time, 40 g of the monomer phase was charged over the first 30 minutes and then 940 g over the next 3 hours.

Method B: Preparation of anionic monodisperse polymer particles without surfactant
A 12 liter Morton reaction flask was prepared by adding 2000 g of demineralized water. The flask contents were heated to 80 ° C. with stirring at 150 RPM in a nitrogen atmosphere. A first aqueous phase addition flask was prepared using 1987 g of demineralized water and 13.2 g of sodium metabisulfite. A second aqueous phase addition flask was prepared using 1973 g of demineralized water and 26.4 g of sodium persulfate. A monomer phase addition flask was prepared by adding 2182 g of ethyl methacrylate and 364 g of methyl methacrylate. Next, loading from each addition flask into the reaction flask was started at 5 g / min. The addition flask was reloaded as needed. Samples were taken at various times and the monomer phase feed was stopped when the desired latex particle size was reached. The redox initiator solution charge was extended for 30 minutes beyond the end of the monomer phase addition to keep as little residual monomer as possible. The contents of these flasks were stirred at 80 ° C. for 1 hour, then cooled to 20 ° C. and filtered through 200 μm polycloth. The latex was concentrated to 50% solids by ultrafiltration.

Method C: Preparation of cationic monodisperse polymer particles without surfactant
A 12 liter Morton reaction flask was prepared by adding 4000 g of demineralized water. The flask contents were heated to 80 ° C. with stirring at 150 RPM in a nitrogen atmosphere. An initiator solution addition flask was prepared using 1974 g of demineralized water and 26.4 g of 2,2′-azobis (2-methylpropionamidine) dihydrochloride. A monomer phase addition flask was prepared by adding 2182 g of ethyl methacrylate and 364 g of methyl methacrylate. Next, loading from each addition flask into the reaction flask was started at 5 g / min. The addition flask was reloaded as needed. Samples were taken at various times and the monomer phase feed was stopped when the desired latex particle size was reached. The redox initiator solution charge was extended for 30 minutes beyond the end of the monomer phase addition to keep as little residual monomer as possible. The contents of these flasks were stirred at 80 ° C. for 1 hour, then cooled to 20 ° C. and filtered through 200 μm polycloth. The latex was concentrated to 50% solids by ultrafiltration.

Preparation of comparative polymer particle CP-1 (broad particle size distribution)
An organic composition was prepared by dissolving 47.9 g cellulose acetate butyrate (Eastman Chemicals CAB 551-0.2) in 112.7 g ethyl acetate at 68 ° C. with mixing. An aqueous composition was prepared by dissolving 13.4 g Alkanol XC ™ (DuPont Corp.) 10% solution in 361.3 g water and heating to 68 ° C. This aqueous phase was added to the organic phase using low shear mixing, and the combined phases were passed twice through a Gaulin colloid mill high shear mixer to form a particulate premix. The obtained premix was subjected to a rotary evaporator to remove the ethyl acetate, thereby producing a fine particle dispersion of cellulose acetate butyrate.

Preparation of comparative polymer particle CP-2 (broad particle size distribution)
CP-2 was prepared as in Method A, except that the aqueous and monomer phases were combined, pre-emulsified, and fed to the reaction flask from a single addition flask. The monomer emulsion was not stable, there was a monomer pool in the reactor, and the heat of reaction was not constant. The particle size distribution data obtained by the Ultrafine Particle Analyzer showed a bimodal particle size distribution.

Characterization of polymer particles
The Tg of the polymer material dried at the glass transition temperature , as measured by differential scanning calorimetry (DSC) using a heating rate of 20 ° C./min, is shown in Table II below. Tg is defined herein as the inflection point of the glass transition.

Particle size measurement
The polymer particles were characterized by an ultrafine particle analyzer (UPA) manufactured by Leeds & Northrup. Graphs for representing particle size data are obtained in two forms: a histogram (as shown in FIG. 1) and a cumulative plot (as shown in FIG. 2). The percentile points in FIG. 2 indicate a predetermined percentage of the capacity that is smaller than the indicated size. This 50% is used as the “average particle size”. The decimal ratio is defined as the ratio of the particle size at the 90th percentile point to the particle size at the 10th percentile point. The smaller the decimal ratio, the narrower the particle size distribution. For example, according to FIG. 2, the 90th percentile is 0.74 μm and the 10th percentile is 0.31 μm, so the decimal ratio is 2.39 (0.74 divided by 0.31).

  The preparation method, composition and properties of the polymers used in the above examples are summarized in Table II.

Low Tg particle dispersion B-1
B-1 is a polyurethane dispersion, Witcobond W-320 ™ (CK Witco Corporation). Because this dispersion is nonionic, it is compatible with anionic or cationic polymer particle dispersions. This dispersion has an average particle size of 3 μm and a Tg of −12 ° C. (all quoted from CK Witco Corporation).

Preparation of Control Element C-1 A single layer inkjet porous medium was prepared by applying an aqueous solution comprising particles CP-1 and B-1 onto polyethylene coated paper treated by corona discharge prior to application. . The concentrations of CP-1 and B-1 were 36% by mass and 7.2% by mass, respectively. 0.4% anionic surfactant, Olin 10G ™ (Olin Corp.) was used in the coating solution to control the surface tension during application. This coating solution was applied to 108.9 g / m ² (10 cc / ft ² ), dried at 49 ° C. for 3 minutes, and then further dried at 25 ° C. for 8 minutes by forced air circulation.

Preparation of Control Element C-2 Control element C-2 was prepared in the same manner as C-1, except that polymer particle CP-2 was used.

Preparation of Control Element C-3 Control Element C-3 is a coating solution containing 32% polymer particles P-7 and 3.2% Airvol 205 ™ polyvinyl alcohol (PVA) (Air Products Corp.). This was prepared in the same manner as C-1.

Preparation elements 1-12 of elements 1-12 of the present invention are polymer particles P-2, P-3, P-4, P-6, P-7, P-9, P-10, P-11, P Prepared in the same manner as C-1 except that -12, P-14, P-15, and P-16 were used respectively.

Scanning electron microscopy (SEM)
A piece of the element was cut out and mounted on a SEM stub using carbon tape. In order to impart conductivity, a metal coating was applied to the surface of this sample using platinum-palladium in a vacuum deposition apparatus. The sample was examined on a Hitachi S-4100 field emission electron gun scanning electron microscope using 5 keV electron beam energy. This sample was imaged at a tilt angle of 0 ° and a representative image of the coating was captured at a magnification range of 2,000x to 50,000x.

  SEM images of control elements C-1 and C-2 and elements 1, 5, and 11 of the present invention are shown in FIGS.

Ink-absorbing inkjet samples were loaded into an Epson Stylus Photo 820 printer with a color ink cartridge T017 and a black ink cartridge T026 to print preassembled digital images consisting of color patches and photographs. Immediately after the printed sample was discharged from the printer, the area of the printed sample where the ink adhered was rubbed with a finger. “Immediate drying” is defined as a print that is dry to the touch and not stained or damaged by the frictional action of the finger. If the particles coalesce upon drying after application to form a continuous film, the ink would have formed droplets on the surface and did not penetrate through the layer. Thus, such images would have a low optical density and would be easily soiled by friction.

Fusing The printed sample was fused at a rate of 2.5 cm / sec between a set of hot-pressing rollers where at least one roller was heated to a temperature of 150 ° C.

Test for water and stain resistance A Ponceau red dye solution was prepared by dissolving 1 g of dye in 1000 g of a mixture of acetic acid and water (5 parts: 95 parts). A Ponceau red dye solution approximately 1 cm in diameter was placed on the surface of the sample for 5 minutes. The liquid was then wiped with a Sturdi-Wipes paper towel. The test area was viewed and recorded. The absence of dye stain remaining on the image indicates the presence of a water resistant overcoat layer and the red stain on the image indicates the absence of a water resistant overcoat layer.

Image quality The above elements were visually inspected and evaluated according to the following ratings:
Good = no dirt Normal = some dirt bad = bad dirt

  The above evaluation results for the control elements as well as the elements of the present invention are summarized in Table III below.

  The above results indicate that the ink jet recording element of the present invention had improved ink absorption, image quality, and stain resistance compared to the control element.

Example 2
In this example, many types of ink jet elements were prepared on a transparent biaxially oriented polyethylene terephthalate film used in medical imaging applications. In order to observe in the transmission mode, it is desirable to obtain an image having a low haze after fusing.

Preparation of Control Element C-4 This element comprises 82.5: 7.5: 3: 7 mass ratio of fumed alumina (Cab-O-Sperse PG003 ™ (Cabot Corp.)), PVA (GH-23 (Nippon Ghosei)), 2,3-dihydroxy-1,4-dioxane (Clariant Corp.), and mordant material MM, which is a single-layer inkjet porous receiving layer having a thickness of 20 μm. MM is a crosslinked hydrogel polymer particle having an average particle size of 80 nm prepared from 87% by weight N-vinylbenzyl-N, N, N-trimethylammonium chloride and 13% by weight divinylbenzene. In this coating solution, 0.07% nonionic surfactant, Olin 10G ™ (Olin) was used to control the surface tension during application.

Preparation of Control Element C-5 This element consists of PVA (Airvol 205 ™) with a mass ratio of 48.8: 48.8: 2.4, 5.9 μm silica gel (23F (Crossfield)), and 2,3-dihydroxy-1, It is a single-layer inkjet porous layer made of 4-dioxane (Clariant Corp.) and having a thickness of 20 μm.

Preparation of Elements 13-26 of the Invention These elements were prepared in the same manner as Elements 1-12 except that various polymer particles were used and coated on a polyethylene terephthalate film. Specific particles used for each element are listed in Table IV below.

Ink absorption and fusing Printing and fusing for these elements were performed as in Example 1. Pre-assembled digital images containing black and white medical X-ray images and grayscale were used for printing.

Film appearance after fusing The above elements were inspected after fusing and graded as follows.
Good = clear or transparent Bad = cloudy

  The following results were obtained.

  The above results indicate that the layer compositions commonly used for ink jet elements (eg, control elements C-4 and C-5) are not suitable for medical imaging applications due to their high light scattering properties. Is shown. Elements 13-26 of the present invention are particularly suitable for inkjet medical imaging applications because they provide a transparent image in addition to fast ink absorption and sufficient image quality.

Element 13 was further examined for pore volume in the ink receiving layer. This test was performed using Mercury Intrusion Porosimetry (model 9520) manufactured by Micromeritics Instrument Corporation. The volume of mercury penetrating into the pores was measured as a function of the hydraulic pressure applied to the mercury / sample combination. The amount of pore volume was measured as the amount of mercury penetrating by the change in capacitance as the mercury column above the mercury / sample portion decreased as mercury penetrated into the sample. For element 13, a pore volume of 19.5 mL / m ² was measured.

Example 3
In this example, two sets of pigment-based ink were printed on element 3 of the present invention, then dried and fused as described in Example 1. When these two sets of pigment ink were measured by the particle size measurement UPA described in Example 1, the average particle size of the pigment dispersion was different. Epson inks used in Epson C80 printers (filled in Epson ink cartridges T0322 (cyan), T0323 (magenta), and T0324 (yellow)) and US Pat. Nos. 5,679,138, 5,670,139, 6,152,999, And three more pigment-based inks prepared by the inventor according to methods similar to those described in US Pat. No. 6,210,474 were used for printing. The particle sizes of the pigments used in these inks are listed in Table V below.

After fusing, the prints were inspected for rub resistance in the area where the ink was deposited by rubbing the sample 8 times with a dry paper towel under a pressure of 200 g over a 3.5 cm diameter area. These elements were examined and graded as follows.
Good = Image was not damaged Poor = Image was scraped and scratched on the surface

  The following results were obtained.

  The above results show that when the pigment having an average particle size of 90 nm or more is printed on the element 3 of the present invention, the friction resistance is poor.

  These prints were cut and examined for the position of the colorant by optical microscopy. It was clear that the pigments used in inks 1 and 2 remained on the surface of element 3 and the pigments used in inks 3-6 penetrated into the ink receiving layer. This indicates that the average particle size of the pigment used in the ink is preferably less than 90 nm in order to achieve sufficient rub resistance in the imaged area.

  Although the present invention has been described in detail with respect to certain preferred embodiments for illustration, it is to be understood that changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. is there.

  Other preferred embodiments of the invention will now be described in the context of the claims.

  [1] An ink jet recording element comprising a support carrying a fusible porous image-receiving layer comprising at least two types of hydrophobic polymer particles having different glass transition temperatures, An ink jet recording element, wherein the first type of hydrophobic polymer particles that are monodisperse have a Tg greater than about 60 ° C and the second type of hydrophobic polymer particles have a Tg of less than about 25 ° C.

  [2] The first type of hydrophobic polymer particles that are substantially monodisperse have an average particle size of about 0.2 μm to about 2 μm, and particles at the 90th percentile of the particle size distribution curve The element of [1], having a particle size distribution in which the ratio of diameter to particle size at the 10th percentile of the particle size distribution curve is less than about 2.

  [3] The element of [1], wherein the first type of hydrophobic polymer particles that are substantially monodisperse have a Tg of about 60 ° C to about 140 ° C.

  [4] The element of [1], wherein the second type of hydrophobic polymer particles has a Tg of about -60 ° C to about 25 ° C.

  [5] The element of [1], wherein the mass ratio of the first type of hydrophobic polymer particles to the second type of hydrophobic polymer particles is from about 10: 1 to about 2.5: 1.

[6] The element of [1], wherein the porous image-receiving layer is applied in an amount of about 10 g / m ² to about 60 g / m ² .

  [7] The element according to [1], wherein the support is a resin-coated paper or a transparent polymer film.

  [8] The element according to [1], wherein the porous image receiving layer is crosslinked.

  [9] The element according to [1], wherein the porous image-receiving layer contains an ultraviolet absorber.

[10] The element according to [1], wherein the fusible porous image receiving layer has a pore volume of about 5 to about 50 mL / m ² .

It is a printout of a sample of particle size data obtained using an ultrafine particle analyzer. It is a printout of a sample of particle size data obtained using an ultrafine particle analyzer. It is a scanning electron micrograph of the above-mentioned reference element C-1. It is a scanning electron micrograph of the above-mentioned reference standard element C-2. 2 is a scanning electron micrograph of element 1 of the present invention described above. It is a scanning electron micrograph of the element 5 of the above-mentioned this invention. 2 is a scanning electron micrograph of element 11 of the present invention described above.

Claims (2)

An ink jet recording element comprising a support carrying a fusible porous image-receiving layer comprising particles consisting essentially of at least two types of hydrophobic polymer particles having different glass transition temperatures, The first type of hydrophobic polymer particles (except for the hollow pigment particles), which are substantially monodispersed, have a glass transition temperature higher than 60 ° C., and the second type of hydrophobic polymer particles is 25 ° C. Has a lower glass transition temperature than
The first type of hydrophobic polymer particles are substantially monodisperse and the particle size at the 90th percentile of the particle size distribution curve is relative to the particle size at the 10th percentile of the particle size distribution curve. An ink jet recording element provided that it has a particle size distribution with a ratio of less than 2 and an average particle size of 0.2 μm to 2 μm. A method for recording an inkjet image, the method comprising:
(A) a medium comprising a support carrying a fusible porous image-receiving layer comprising particles consisting essentially of at least two types of hydrophobic polymer particles having different glass transition temperatures, The first type of hydrophobic polymer particles, which are substantially monodisperse, have a glass transition temperature higher than 60 ° C., and the second type of hydrophobic polymer particles have a glass transition temperature lower than 25 ° C. But,
The first type of hydrophobic polymer particles are substantially monodisperse and the particle size at the 90th percentile of the particle size distribution curve is relative to the particle size at the 10th percentile of the particle size distribution curve. Providing a medium having a particle size distribution in which the ratio is less than 2 and having an average particle diameter of 0.2 μm to 2 μm, and printing the medium; and (b) heating the medium and And / or pressurizing to form a substantially continuous transparent layer on the surface of the medium.

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