JP5645384B2 - ink - Google Patents

Description

The present disclosure relates to an ink for MICR inkjet including stabilized magnetic single crystal nanoparticles, where | K1 |, which is the absolute value of magnetic anisotropy of the magnetic nanoparticles, is 2 × 10 ⁴ J / m ³ or more. The magnetic nanoparticles may be ferromagnetic nanoparticles such as FePt. The ink contains a magnetic material that minimizes the size of the particles, resulting in excellent dispersion of the magnetic pigment and dispersion stability, particularly in non-aqueous ink jet inks. The smaller size of the magnetic ink particles further retains excellent magnetism, thereby reducing the loading of magnetic particles required in the ink.

  Innumerable challenges have been made to develop MICR inkjet inks. First, most if not all inkjet printers have a fairly limited particle size for all particle components of the ink, because the inkjet ejects ink onto the substrate. This is because the size of the print head nozzle is extremely small. The size of an inkjet head nozzle is generally on the order of about 40-50 μm, but can be less than 10 μm. This small nozzle size means that any particulate matter contained in an ink jet ink composition intended for use in an ink jet printer should be free of nozzle clogging problems. , Suggesting that it must be a very small particle size. However, even when the particle size is smaller than the nozzle size, the particles further agglomerate or aggregate and cluster, causing the agglomerate size to exceed the nozzle size and hence the There is also a possibility that the nozzle is blocked. In addition, the particulate matter may precipitate during printing, thereby forming a scab, which can clog the nozzle and / or disturb the flow parameters. obtain.

  Another concern regarding the formulation of MICR inkjet inks is that the ink must be fluid and not dry. Therefore, as the pigment size increases, the density increases correspondingly, which makes it difficult to maintain the pigment in a suspended or dispersed state in the liquid ink composition.

  The MICR ink contains a magnetic material for providing the required magnetism. It is essential that the magnetic material retains a sufficient magnetic charge so that the printed characters maintain their readable characteristics and are easily detected by a detection device or reader. The magnetic charge held by the magnetic material is called “residual magnetism”. The “coercive force” of a magnetic material refers to a magnetic field H that must be applied to the magnetic material in a symmetric and circular magnetization scheme in order to eliminate the magnetic induction B. Therefore, the coercivity of the magnetic material is the coercivity of the material in the hysteresis loop, and its maximum induction is almost similar to saturation magnetic induction. The observed remanent magnetization and the observed coercivity of the magnetic material depend on the magnetic material having some anisotropy that provides a suitable orientation for the magnetic moment in the crystal. There are mainly four types of anisotropic forces that determine the coercivity of the particles, which are magnetocrystalline anisotropy, strain anisotropy, exchange anisotropy, and shape anisotropy. Two types of anisotropy that dominate in particular are 1) shape anisotropy (in this case the preferred magnetic orientation is parallel to the axis of the magnetic crystal), and 2) crystal magnetic anisotropy (in this case Electron spin-orbit coupling aligns the magnetic moment with the preferred crystal axis).

  The magnetic material must have the ability to exhibit sufficient remanence and generate a MICR readable signal that can be sustained over time after exposure to a magnetizing source. Generally, as defined by industry standards, acceptable levels of magnetic charge are between 50 and 200 signal level units (Signal Level Units), with a nominal value of 100. This is defined by a standard developed by ANSI (the American National Standards Institute). Lower signals may not be read by the MICR reading device, and larger signals may not provide accurate readings. The document being read employs MICR-printed characters as a means of certifying and authenticating the provided document, so MICR characters or other indications may be skipped or misread for any character. It is important that the data is accurately read. Thus, for MICR purposes, the remanence should be at least 20 emu / g. Higher remanence values correspond to signals that can be read more powerfully.

  Residual magnetism tends to increase as a function of particle size and magnetic pigment coating density. Therefore, as the size of the magnetic particles decreases, the magnetic particles tend to be accompanied by a corresponding decrease in remanence. As the size of the magnetic particles decreases and as the percentage concentration of magnetic particles in the ink composition reaches a practical limit, it becomes increasingly difficult to achieve sufficient signal strength. The higher the value of remanence, the lower the total percentage of magnetic particles required in the ink formulation compared to the ink formulation with a higher percentage of magnetic particles, improving the suspension properties, and settling. The chance of happening is reduced.

  In addition, for proper functioning in both drop-on-demand type printing devices, such as heated bubble jet printers and piezoelectric printers, and continuous type printing mechanisms, for MICR inkjets The ink typically exhibits a low viscosity on the order of less than about 15 cP or about 2-8 cP at the jetting temperature (where the jetting temperature ranges from about 25 ° C. to about 140 ° C.). There must be. However, the use of low viscosity fluids adds to the problem of well incorporating magnetic particles into the ink dispersion because of the lower viscosity compared to higher viscosity and dense fluids. This is because the sedimentation of particles is accelerated in a fluid having a low viscosity.

Magnetite (iron oxide, Fe ₂ O ₃ ) is a common magnetic material used in MICR inkjet inks. Magnetite has a low magnetocrystalline anisotropy, K1, of −1.1 × 10 ⁴ J / m ³ . Magnetite in the form of needle-like crystals, with one crystal dimension much larger than the other, has an aspect ratio (D _major / D _minor ) of the single crystal major axis dimension to minor axis dimension of (2: 1) or higher. To help increase the remanence and coercivity performance in the ink. Acicular magnetite typically has a short axis and a long axis each having a size of 0.6 × 0.1 μm and a large shape anisotropy (6/1). The loading of iron oxide in the ink is typically about 20-40 weight percent. However, due to the large size and aspect ratio of the magnetite particles in the form of needle crystals, it is difficult to disperse and stabilize in ink, especially for use in ink jet printing. Furthermore, spherical or cubic magnetite is smaller in size (less than 200 nm in any direction), but has a low shape anisotropy (D _major / D _minor ) of about 1. As a result, because the overall anisotropy is low, spherical or cubic magnetite has low remanence and coercivity, and a loading of over 40 weight percent is required to provide magnetic performance. There are many cases. Thus, spherical and cubic magnetites have desirable small particle sizes of less than 200 nm in either direction, but they must be fairly loaded so that they can be dispersed and stable. It becomes difficult to hold the dispersion. Furthermore, carrying a large amount of an inert, non-melting magnetic material adversely affects other ink performances such as adhesion to the substrate and scratch resistance. As a result, this reduces the suitability of magnetite for ink jet printing inks.

US Patent Application Publication No. 2008/0000384 US Patent Application Publication No. 2007/0142492 US Patent Application Publication No. 2007/0120910

  In addition, because magnetite has a specific gravity of about 7, magnetite tends to settle to the bottom of the fluid ink composition. This results in a heterogeneous fluid having a lower layer rich in iron oxide and an upper layer low in iron oxide. Furthermore, suitable ink jet oxides must generally be hydrophilic in nature in order to provide good dispersion properties and also good emulsion properties. The latter parameter minimizes settling and improves the performance of the magnetic particles such that the magnetic particles further exhibit adequate wetting with other water soluble components commonly present in ink jet ink compositions. Directly related.

  These problems commonly associated with the use of iron oxide in MICR inkjet inks have been addressed in several different ways. For example, it is known to use surfactants in combination with metal oxides of very small particle size for the purpose of effectively keeping the magnetic component in suspension or dispersion in the ink composition. . Another means for obtaining an ink jet ink suitable for use in an ink jet printer or to obtain a MICR readable print is to coat the metal magnetic material with a specific hydrophilic coating and to produce the particles It is possible to maintain the magnetic metal in the suspension.

  Yet another type of ink used for MICR inkjet printing is xFerrone (R) (iron complex pigment) ink, which is G7 Productivity Systems Inc. Is a water-based ink commercially available from G7 Productivity Systems, Inc. (VersaInk®). The inks can be used on HP®, Canon®, Lexmark®, Dell® and Epson® printers. For example, it has various uses such as improving the reliability of check scanning and eliminating the queue of store cashiers. However, these inks have excellent magnetic pigment dispersibility and dispersion stability, while maintaining excellent magnetism and reducing the size of magnetic material particles that reduce the required amount of particles. Does not show the characteristics of inclusion. The reason is that the major axis / minor axis ratio of the magnetic particles used in such conventional inks must have a ratio of at least (2: 1), resulting in needle-like This is because the size of the magnetite particles is 0.6 μm on the long axis. This reduces the dispersibility and the stability of the dispersion.

The ink in the present embodiment includes a carrier, an optional colorant, stabilized magnetic single crystal nanoparticles, a vehicle containing linear alkanes, branched alkanes, and alcohols, and a cobalt salt of linoleic acid. , only contains the absolute value of the magnetic anisotropy of the magnetic nanoparticles, is 2 × 10 ⁴ J / m ³ or more.

  In general, the disclosure herein relates to inks comprising magnetic nanoparticles exhibiting great anisotropy dispersed in a carrier medium. The ink may further include one or more resins, one or more colorants, and / or one or more additives. In one embodiment, the magnetic nanoparticles are metal nanoparticles. In another embodiment, the magnetic nanoparticles are single crystal ferromagnetic nanoparticles. These inks are suitable for use in a variety of applications, including MICR applications. Furthermore, these printed inks can also be used for decorative purposes, even if the inks thus obtained do not exhibit sufficient coercivity and remanence that are suitable in MICR applications. . The inks disclosed herein exhibit stability, dispersibility, and magnetism superior to inks containing magnetite. Hereinafter, the ink composition will be described in detail.

  The disclosure herein is not limited to the specific embodiments described herein, and one of ordinary skill in the art will be able to modify certain components and processes based on the disclosure herein. Is also possible. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

  In this specification and in the claims that follow, singular forms such as “a”, “an”, and “the” also include the plural (subject to clearly different contexts). Except in case).

  In the present specification and claims, the term “ink” also refers to “ink composition” and vice versa.

Suitable magnetic materials for use in the present disclosure include single crystal nanoparticles that exhibit large anisotropy. As used herein, “large anisotropy” is defined as the absolute value of the magnetocrystalline anisotropy of a particle, and the absolute value is 2 × 10 ⁴ J / m ³ or more. Suitable magnetic materials are about 2 × 10 ⁴ J / m ³ to about 5 × 10 ⁷ J / m ³ , such as about 5 × 10 ⁴ J / m ³ to about 5 × 10 ⁶ J / m ³ , or about 7 Materials having a K1 value of x10 ⁴ J / m ³ to about 4 × 10 ⁶ J / m ³ are also suitable. In some embodiments, the single crystal nanoparticles can be magnetic metal nanoparticles or ferromagnetic nanoparticles with great anisotropy, including, for example, Co and Fe (cubic). Furthermore, the magnetic nanoparticles may be bimetallic or trimetallic, or mixtures thereof. Suitable bimetallic based magnetic nanoparticles, CoPt, fcc phase FePt, fct phase _{FePt, FeCo, MnAl, MnBi,} CoO · Fe 2 O 3, BaO · 6Fe 2 O 3, and a mixture thereof and the like (these Not limited to). In another embodiment, the magnetic nanoparticles are fct phase FePt. Examples of trimetallic nanoparticles include ternary mixtures of the magnetic nanoparticles described above, or core / shell structures that form trimetallic nanoparticles, such as Co-coated fct phase FePt. Not.)

  These magnetic nanoparticles may be prepared by any method known to those skilled in the art, such as by ball milling larger particles (a method commonly used in nano-sized pigment production). ), Followed by annealing (annealing). Annealing is generally required because the ball milling produces amorphous nanoparticles that must then be crystallized to the desired single crystal form. . It is also possible to produce nanoparticles directly by RF plasma. A suitable large-scale RF plasma reactor is available from Tekna Plasma Systems. It is also possible to produce nanoparticles by various in situ methods in a solvent (including water).

The average particle size of the magnetic nanoparticles may be, for example, about 10 nm to about 300 nm in all directions. They can have various shapes such as a spherical shape, a cube, and a hexagonal column. In one embodiment, the size of the nanoparticles is from about 10 nm to about 500 nm, such as from about 50 nm to about 300 nm, or from 75 nm to about 250 nm, although their amount can be outside these ranges. As used herein, the “average” particle size is typically expressed as d ₅₀ or defined as the median particle size value at the 50th percentile of the particle size distribution, where the particles in that distribution are 50% is larger than the d ₅₀ particle size value, and the remaining 50% of the particles in the distribution are smaller than the d ₅₀ value. The average particle size can be measured by a light scattering technique for estimating the particle size, for example using a dynamic light scattering method. The term “particle diameter” refers to the length of the pigment particle derived from an image of the particle obtained by transmission electron microscopy (TEM).

The ratio of the _major axis to the minor axis (D _major / D _minor ) of the _nanosingle crystal can be less than about (4: 1), such as less than about (3: 2) or less than about (2: 1). .

  The required loading of magnetic nanoparticles in the ink may be from about 0.5 weight percent to about 15 weight percent, such as from about 5 weight percent to about 10 weight percent, or from about 6 weight percent to about 8 weight percent. , Their amounts may deviate from these ranges.

  The magnetic nanoparticles can have a remanence of about 20 emu / g to about 100 emu / g, such as about 40 emu / g to about 80 emu / g, or about 50 emu / g to about 70 emu / g, It may be out of the range.

  The coercivity of the magnetic nanoparticles can be, for example, from about 200 Oersted to about 50,000 Oersted, such as from about 1,000 Oersted to about 40,000 Oersted, or from about 10,000 Oersted to about 20,000 Oersted. Although they can, they may be outside these ranges.

  The saturation magnetic moment can be, for example, from about 20 emu / g to about 150 emu / g, such as from about 30 emu / g to about 100 emu / g, or from about 50 emu / g to about 80 emu / g, although they are outside these ranges It may be.

Examples of suitable magnetic nanoparticle compositions having a large magnetocrystalline anisotropy, K1, are shown in Table 1. Table 1 also shows a reference magnetite. The actual coercivity obtained with nanocrystalline materials can be lower than the maximum coercivity shown here, because the coercivity is strongly size dependent. The peak coercivity for Fe and Co appears when the particle size is about 20 nm, while the peak coercivity for CoO.Fe ₂ O ₃ is about 30 nm for those particles. Appears when Another suitable magnetic material having high crystal magnetic anisotropy includes, for example, CoPt having a K1 value of 4.9 × 10 ⁶ J / m ³ .

  Examples of magnetic nanocrystals with high magnetocrystalline anisotropy prepared in the literature are shown in Table 2. Any of the particles shown below are suitable for MICR ink applications.

  However, even if the material has a large intrinsic crystalline magnetic anisotropy, it will have a high remanence or coercivity that renders it suitable for MICR applications. There is no guarantee. Similarly, the FePt alloy, Fe or Co does not necessarily have the required remanence or coercivity. In general, for MICR applications, the material is 1) large intrinsic crystalline magnetic anisotropy, and 2) single crystal domains whose domain size is at least about 10 nm (exact minimum size limits are The specific material is suitable only if it has both (depending on the material).

Furthermore, producing an ink containing bimetallic magnetic nanoparticles whose absolute value of the magnetocrystalline anisotropy K1 is greater than 2 × 10 ⁴ J / m ³ and is at least one of FeCo or Fe ₂ O _3. Is possible. This may be done by various means known to those skilled in the art. For example, an ink containing FePt crystalline nanoparticles may be mixed with an ink containing Fe ₂ O ₃ . Alternatively, FePt crystalline nanoparticles and Fe ₂ O ₃ may be added into the ink during ink synthesis. Thus, such mixtures combine the relatively inexpensive Fe ₂ O ₃ with the improved magnetic properties and dispersibility of FePt crystalline nanoparticles to produce MICR inkjet inks. In such mixtures, the ratio of magnetic nanoparticles to FeCo or Fe ₂ O ₃ is about (0.1: 99.9) or vice versa, eg about (10:90), or about (30:70). Or about (50:50). In such mixtures, the loading requirement is, for example, from about 0.5 weight percent to about 15 weight percent of the ink, such as from about 2 weight percent to about 10 weight percent, or from 5 weight percent to about 8 weight percent. , Their amounts may deviate from these ranges.

  The ink composition further includes a single carrier material or a mixture of two or more carrier materials. For example, in water-based inkjet ink compositions, water or a mixture of water and one or more other solvents can be used as a suitable carrier material. In the case of a solid (or phase change) ink jet ink composition, the carrier may contain one or more organic compounds.

  In the case of a radiation (eg, ultraviolet light) curable ink composition, the ink composition typically includes a carrier material that is a curable monomer, curable oligomer, or curable polymer, or a mixture thereof. included.

  The ink composition according to the present disclosure may contain one or more binder resins.

  The binder resin may be any suitable material.

  The MICR ink according to the disclosure herein may be produced as a colored ink by adding a colorant during ink production. Various desired or effective colorants can be used in the ink composition, and include pigments, dyes, mixtures of pigments and dyes, mixtures of pigments, mixtures of dyes, and the like.

  One or more waxes may be added to the MICR ink jet ink to improve image density and effectively prevent offset and image smearing with the read head.

  In some cases, the ink composition may further contain an antioxidant.

  In some cases, the ink composition may further contain a viscosity modifier.

  Additives to other optional inks include fining agents, tackifiers, adhesives, and plasticizers. A surfactant may be used in the ink.

  The ink composition disclosed in the present invention can be prepared by various desired or suitable methods.

  The MICR ink according to the disclosure herein may be, for example, an aqueous ink, an oil ink, a curable ink, a solid ink, or a hot melt ink.

  Magnetic metal particle inks can generally be printed on a suitable substrate.

  Various suitable printing methods may be used to print the MICR ink on the substrate.

  The inks disclosed herein can be used for both MICR and non-MICR applications.

Example 1:
The triamide resin (prepared as described in Example II of US Pat. No. 6,860,930) was processed through a blender to form a powder. About 750.72 g of powdered triamide resin and about 239.7 g of Nipex® 150 carbon black (obtained from Degussa Canada, Burlington, Ontario) Mix in a Little Ford M5 blender at 0.8 A for about 30 minutes. The powder mixture was converted into a dowel (DAVO) reversing twin screw extruder (Germany, Troisdorf, Germany) Deutsch Appalate-Feltryp Organizetion GmbH / Co (Dutsche Apparate-Vert. ) At a rate of 0.8 pounds / hour. The contents of the extruder were then mixed at 70 ° C. and 50 RPM. The outlet temperature was set to 75 ° C. The dispersion thus extruded, extrudate A, was melt mixed with other ink components to form carbon black inks as described in Examples 2-5.

Example 2:
Extrudate A (13.13 wt.% Of total ink weight, about 19.70 g) prepared according to Example 1 and Petrolite CA-11 diurethane dispersant (3.95 wt.% Of total ink weight, Approximately 5.92 g) was weighed into a first 250 ml beaker (A). Kemamide (registered trademark) S180 (15.19% by weight of the total ink weight, 22.79 g) manufactured by Crompton Corp., manufactured by Arakawa Chemical Industries Ltd. (Arakawa Chemical Industries Ltd.) KE100 resin (10.85% by weight of total ink weight, approximately 16.28 g), and Naugard® N445 (0.12% by weight of total ink weight) from Crompton Corp. About 0.18 g) was weighed into a second 250 ml beaker (B). Polyethylene wax from Baker Petrolite (54.26% by weight of total ink, approximately 81.39 g), and US Pat. No. 6,309,453 (all by reference) Weigh the urethane resin described in Example 4 of the present invention (2.5% by weight of total ink, about 3.74 g) into a third 250 ml beaker (C). I got in. Beakers A, B and C were heated at 130 ° C. for about 3 hours. After heating for 2 hours, the contents of Beaker B were stirred with a heated spatula to promote melting and dissolution of the mixture, but this was repeated 30 minutes later. When the mixture in beaker B was completely dissolved and melted, the contents of beaker B were poured into beaker A.

  The contents of Beaker A were sonicated six times for 30 seconds using a Sonic Dismembrator Model 500 Sonifier (Sonic Dismembrator Model 500 Sonifier) for a total of 3 minutes of sonication time. During sonication, the beaker was rotated while maintaining the temperature below 130 ° C. so that the treatment was evenly applied to the entire mixture. After the first 3 minutes of sonication, the beaker (A) was heated at 110 ° C. for 30 minutes. The sonication on beaker (A) is then repeated two more times, and the contents in beaker (C) are placed in beaker (A) during the first 30 seconds of sonication for the third sonication. Poured in little by little. The carbon black ink thus prepared exhibited a viscosity of about 10.8 centipoise (cps) as measured with an AR2000 Rheometer manufactured by TA Instruments. The ink was then filtered through a 1 μm glass fiber disc filter and then a 0.45 μm glass fiber disc filter at 110 ° C. under a pressure of 15 pounds per square inch (psi). The final ink was then cooled to room temperature and tested on a Xerox (R) Phaser (R) 8400 piezoelectric inkjet printer. The composition of this ink is shown in Table 3.

Example 3:
Except that WB-5 diurethane dispersant (available from Baker Petrolite) was used in place of Petrolite CA-11 (available from Baker Petrolite) Thus, a carbon black ink was prepared according to the description in Example 2. The composition of this ink is shown in Table 3.

Example 4:
Carbon black ink was prepared according to the description of Example 2 except that WB-17 diurethane dispersant (available from Baker Petrolite) was used instead of Petrolite CA-11. Prepared. The composition of this ink is shown in Table 3.

Example 5:
The following ingredients were melted and stirred at 125 ° C. in a 4 liter beaker (A): Extrudate A prepared according to the description of Example 1 (13.13 wt% of total ink weight, about 367.64 g) Petrolite CA-11 (3.94 wt% of total ink weight, approximately 110.49 g), Chemamide® S180 (total ink weight) from Crompton Corporation. 15.19 wt%, about 425.41 g), KE100 resin (10.85 wt% of total ink weight, about 303.86 g) from Arakawa Chemical Industries Ltd., and Crompton Corporation (Crampton Corp.) Nowguard ( augard) (R) N445 (0.12 wt% of the total ink weight, about 3.40 g). A heating mantle and a mechanical stirrer were attached to the beaker (A). The carbon black dispersion was heated and stirred at 125 ° C. for 1 hour. In a second 4 liter beaker (B), distilled polyethylene wax from Baker Petrolite (US 2007/0120916 (hereby incorporated by reference in its entirety). And 54.24% by weight of the total ink weight, about 1,519.32 g), and in Example 4 of US Pat. No. 6,309,453. Of urethane resin (2.53% by weight of the total ink weight, about 70.80 g) was melt-mixed at 125 ° C. A heating mantle and a mechanical stirrer were also attached to the beaker (B). The resin dispersion in the beaker (B) was heated and stirred for 1 hour to completely melt and mix all the resins.

  The contents of the beaker (A) were homogenized using an IKA Ultra Turrax® T50 homogenizer at 125 ° C. for 30 minutes. The molten resin mixture in beaker (B), maintained at 125 ° C., was added into the homogenized pigment dispersion in beaker (A). Further, the carbon black ink in the beaker (A) was further homogenized over 30 minutes. The rheology of the carbon black ink in the beaker (A) was measured using an AR2000 Rheometer. The resulting carbon black ink was filtered through a 1 μm glass fiber cartridge filter and then a 0.45 μm glass fiber cartridge filter at 115 ° C. under low pressure (less than 5 psi). The ink was then cooled to room temperature. The final ink was tested on a Xerox® Phaser 8860 piezoelectric inkjet printer.

Example 6:
Described in Watari et al., J. Materials Science (which is incorporated herein by reference in its entirety), 23, 1260-1264 (1988). Magnetic Fe particles are prepared according to the procedure described above. The mineral goethite α-FeOOH having a particle size of 0.5 μm is reduced under isothermal heat treatment in a hydrogen atmosphere at 400 ° C. for 2 hours to convert the particles to Fe metal particles, The particles have a size of 20 × 20 × 200 nm, an aspect ratio of 10/1, a remanent magnetic moment of 72.2 emu / g, a coercivity of 1540 oersted, and a magnetocrystalline anisotropy of about 4 × 10 ⁴ J / m. ³ (measured according to Luborsky, Journal of Applied Physics, Volume 32 (3) supplements, 171S-184S (1961)).

Example 7:
Magnetic FePt particles are prepared according to the procedure described by Li et al., J. Applied Physics, 99, 08E911 (2006). 15 nm FePt nanoparticles are chemically synthesized under an argon atmosphere. The X-ray crystal structure of FePt is fcc. The NaCl powder is ball milled for 24 hours. The ball milled NaCl powder is then dispersed in hexane and mixed with the hexane dispersion of as-synthesized fccFePt nanoparticles so that the NaCl to FePt ratio is (100: 1). . The mixture is stirred to evaporate all of the solvent and annealed in forming gas (93% H ₂ , 7% Ar) at 700 ° C. for 2 hours to convert the FePt to the desired fct crystal structure. The salt is washed out with water and the particles are dried. The magnetic Fe particles are cubic, have a size of 15 nm, an aspect ratio of 1/1, a residual magnetic moment of about 40 emu / g, a coercivity of 20,000 Oersted, and a magnetocrystalline anisotropy of 660 × 10 ^4. J / m ³ .

Example 8:
The process described in Example 1 is carried out except that 71.91 g of magnetic Fe particles A prepared as described in Example 6 are added to form Extrudate B.

Example 9:
The process described in Example 8 is carried out except that about 200.00 g of magnetic Fe particles A prepared according to the description of Example 6 are used instead of 71.91 g.

Example 10:
Extrudate B (13.13% by weight of total ink weight, approximately 19.70 g) and Petrolite CA-11 diurethane dispersant (3.95% by weight of total ink weight) prepared as described in Example 8 Weigh approximately 5.92 g) into the first 250 ml beaker (A). Kemamide (registered trademark) S180 (15.19 wt% of the total ink weight, approximately 22.79 g) manufactured by Crompton Corp., manufactured by Arakawa Chemical Industries Ltd. (Arakawa Chemical Industries Ltd.) KE100 resin (10.85% by weight of total ink, approximately 16.28 g), and Naugard® N445 (0.12% by weight of total ink weight) from Crompton Corp. About 0.18 g) into a second 250 ml beaker (B). Polyethylene wax from Baker Petrolite (54.26% by weight of total ink weight, about 81.39 g) and the urethane resin described in Example 4 of US Pat. No. 6,309,453 Weigh (2.5% by weight of total ink weight, approximately 3.74 g) into a third 250 ml beaker (C). Beakers (A), (B) and (C) are heated at 130 ° C. for about 3 hours. After heating for 2 hours, the contents of beaker (B) are stirred using a heated spatula to promote melting and dissolution of the mixture, but this is repeated 30 minutes later. When the mixture in beaker (B) is completely dissolved and melted, the contents of beaker (B) are poured into beaker (A).

  The magnetic carbon black ink thus prepared exhibits an estimated viscosity of about 11 cps as measured with an AR2000 rheometer manufactured by TA Instruments. This viscosity is inferred from the viscosity of an ink containing only carbon black, typically having a viscosity in the range of about 10 to about 11 cps at about 110 to about 140 ° C. If the Fe particles are well dispersed, it is believed that they do not increase in viscosity beyond about 10 to about 20 percent, depending on the concentration of Fe particles. The ink is then filtered through a 6 μm and then optionally 1.0 μm glass fiber disc filter at 110 ° C. under 15 psi pressure. The final ink is then cooled to room temperature and printed. The composition of this ink is shown in Table 3.

Example 11:
The following ingredients are melted and stirred at 125 ° C. in a 4 liter beaker (A): Extrudate C prepared according to the description of Example 9 (13.13% by weight of total ink weight, about 367.64 g) Petrolite CA-11 (3.94 wt% of total ink weight, approximately 110.49 g), Chemamide® S180 (total ink weight) from Crompton Corporation. 15.19 wt%, about 425.41 g), KE100 resin (10.85 wt% of total ink weight, about 303.86 g) from Arakawa Chemical Industries Ltd., and Crompton Corporation (Crampton Corp.) Nowguard ( augard) (R) N445 (0.12 wt% of the total ink weight, about 3.40 g). A heating mantle and a mechanical stirrer are attached to the beaker (A). The magnetite dispersion containing the carbon black is heated and stirred at 125 ° C. for 1 hour. In a second 4 liter beaker (B), polyethylene wax from Baker Petrolite (54.24% by weight of total ink weight, about 1,519.32 g), and US Pat. No. 309,453 (which is incorporated herein by reference in its entirety), the urethane resin described in Example 4 (2.53% by weight of total ink weight, about 70.80 g) at 125 ° C. Melt and mix. A heating mantle and a mechanical stirrer are also attached to the beaker (B). The resin dispersion in the beaker (B) is heated and stirred for 1 hour to completely melt and mix all the resins.

  Using an IKA Ultra Turrax® T50 homogenizer, homogenize the contents in the beaker (A) for 30 minutes, but maintain the temperature at 125 ° C. during homogenization. . The molten resin mixture in beaker (B) is held at 125 ° C. and then added to the homogenized pigment dispersion in beaker (A). Further, the magnetic carbon black ink in the beaker (A) is further homogenized over 30 minutes. The ink thus obtained is filtered through a glass fiber cartridge filter of 6 μm and then 1.0 μm in order under low pressure (less than 5 psi) at 115 ° C., and then the ink is cooled to room temperature. The final ink is then printed using an inkjet printer. The composition of this ink is shown in Table 3.

Example 12:
Magnetic carbon black as described in Example 11 except that an additional 200 g of Extrudate C was added to the ink after the final 30 minute homogenization step and the ink was homogenized over an additional 20 minutes. Prepare ink. The composition of this ink is shown in Table 3.

Example 13:
The process described in Example 8 is performed except that 71.91 g of the magnetic FePt particle B of Example 7 is used instead of 71.91 g of the magnetic Fe particle A of Example 6.

Example 14:
Extrudate D (13.13% by weight of total ink weight, about 19.70 g) and Petrolite CA-11 (3.95% by weight of total ink weight, about 5.70%) prepared as described in Example 13. 92 g) is weighed into a first 250 ml beaker (A). Kemamide (registered trademark) S180 (15.19 wt% of the total ink weight, approximately 22.79 g) manufactured by Crompton Corp., manufactured by Arakawa Chemical Industries Ltd. (Arakawa Chemical Industries Ltd.) KE100 resin (10.85% by weight of total ink, approximately 16.28 g), and Naugard® N445 (0.12% by weight of total ink weight) from Crompton Corp. About 0.18 g) into a second 250 ml beaker (B). Polyethylene wax from Baker Petrolite (54.26% by weight of total ink, approximately 81.39 g), and US Pat. No. 6,309,453 (all by reference) Weigh the urethane resin described in Example 4 of the present invention (2.5% by weight of total ink, about 3.74 g) into a third 250 ml beaker (C). Rub in. Beakers (A), (B) and (C) are heated at 115 ° C. for about 3 hours. After heating for 2 hours, the contents of beaker (B) are stirred using a heated spatula to promote melting and dissolution of the mixture, but this is repeated 30 minutes later. When the mixture in beaker (B) is completely dissolved and melted, the contents of beaker (B) are poured into beaker (A).

  The magnetic carbon black ink prepared in this way has a viscosity of about 11 cps at about 110 ° C. to about 140 ° C. as measured using an AR2000 Rheometer from TA Instruments. It is thought that shows. The ink is then filtered through a 6 μm and then 1.0 μm glass fiber disc filter in order at 110 ° C. under 15 psi pressure. The final ink is then cooled to room temperature and printed using an inkjet printer. The composition of this ink is shown in Table 3.

Example 15:
A magnetic carbon black ink is prepared as described in Example 12 except that WB-5 dispersant is used in place of Petrolite CA-11. The composition of this ink is shown in Table 3.

Example 16:
A magnetic carbon black ink is prepared as described in Example 12 except that WB-17 dispersant is used in place of Petrolite CA-11. The composition of this ink is shown in Table 3.

Example 17:
As described in Example 8, except that about 200.00 g of magnetic FePt particles B prepared according to the description of Example 7 are used instead of 71.91 g of magnetic Fe particles A prepared according to the description of Example 6. The process of is implemented.

Example 18:
The carbon black ink is prepared as described in Example 12, but extrudate E prepared as described in Example 17 is used (instead of Extrudate C prepared as described in Example 9). The composition of this ink is shown in Table 3.

Example 19:
A carbon black ink is prepared as described in Example 14 except that WB-5 dispersant is used in place of Petrolite CA-11. The composition of this ink is shown in Table 3.

Example 20:
A carbon black ink is prepared as described in Example 14 except that WB-17 dispersant is used in place of Petrolite CA-11. The composition of this ink is shown in Table 3.

Example 21:
39.9 g of magnetic FePt particles prepared as described in Example 7 are added to 300 g of deionized water containing 1.3 g of 20% aqueous anionic surfactant Dowfax 2A1 ™. In contrast, 83 g of 18% Nipex® 150 carbon black solution (Degussa Canada, Burlington, Ontario) was added and ball milled over 3 hours. Crushing to produce a pigment dispersion.

  15.25 g diethylene glycol, 5.0 g Jeffamine ED-600, polyether diamine (available from Texaco Chemical Co.), and 20.15 g previously prepared pigment dispersion. Is added to 59.6 g of deionized water with mixing to prepare an aqueous ink composition. This ink can be printed using either a heating type or a piezoelectric ink jet printer.

Example 22:
A stable magnetic carbon black concentrate in dibutyl sebacate (available from Morflex, Inc., NC) is obtained as follows: initial speed 1500 RPM and final speed 2500 RPM. In a 1 liter stainless steel beaker fitted with a DISPERMAT FT (available from VMA-Getzmann GMBH) equipped with a 40 mm high shear mixing dissolver set to 0 g of Nipex® 150G carbon black (available from Cabot) was added to 100.18 g of dibutyl sebacate (Morflex, Inc. x, Inc.) is slowly added with high shear mixing to a solution of 100 g SOLSPERSE 13940 (40% active, available from Avecia). 40 g of magnetic Fe particles A prepared as described in Example 6 are added. The dispersion is continuously stirred for 2 hours after the addition of carbon black and magnetic particles. The amount of the dispersant supported on the pigment is estimated to be about 2.6 mg / m ² assuming the optimum conditions for stabilization.

  This dispersion is further processed in Dispermat SL-C12 (available from VMA-Getzmann GMBH) under the following conditions over 270 minutes: Speed = 2000 RPM; Temperature = 30-55 ° C (water cooled); Circulation rate = about 3 g / sec (passing through 125 mL chamber); Milling bead amount = 100 mL; Bead type = 0.8-1.0 zirconium-silicon dioxide.

Example 23:
The cobalt salt of linolenic acid can be prepared as described in Example 5 of US Patent Application Publication No. 2007 / 0120923A1.

The cobalt salt of linolenic acid is N.I. It may be obtained by direct electrochemical synthesis as described by N. Kumar et al., Canadian Journal of Chemistry (1987), 65 (4), 740-3. Specifically, 0.1 g linolenic acid is dissolved in 50 mL acetone containing 0.04 g Et ₂ NClO ₄ . This solution is added to form a simple electrochemical cell in the form of Pt ⁽⁻⁾ / CH ₃ CN + linolenic acid / Co ⁽⁺⁺⁾ and an initial voltage of 25 V is applied for 45 minutes. Cobalt (II) linolenate precipitates directly during its electrochemical oxidation.

  Alternatively, the cobalt salt of linolenic acid may be prepared by a precipitation process, for example by adding water-soluble cobalt sulfate to a heated sodium salt solution of linolenic acid until precipitation is complete. . The salt so obtained is washed and dried by conventional methods. The cobalt salt of linoleic acid can also be obtained by these methods in the same manner.

Examples 24-27:
Using a high shear mixer, the stable magnetic carbon black concentrate prepared as described in Example 22 is dispersed in a vehicle, ie, a blend of linear and branched alkanes and alcohol, and then the metal salt is added. Thus, ink compositions 24 to 27 containing magnetic particles are prepared. Table 4 lists the specific compositions of Examples 24-27. In some cases, the metal salt may be manganese stearate.

Claims (1)

A carrier,
An optional colorant;
Stabilized magnetic single crystal nanoparticles,
A vehicle containing linear alkanes, branched alkanes, and alcohols;
A cobalt salt of linoleic acid;
Only including,
An ink having an absolute value of magnetic anisotropy of magnetic nanoparticles of 2 × 10 ⁴ J / m ³ or more.