JP2007070637A - Polymerized fatty acid diester useful for formulating hot melt ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent carrier material which is useful for a hot melt ink, and an ink comprising the carrier material. <P>SOLUTION: The solid diester for a hot melt ink can be prepared by reacting a polymerized fatty acid with a long chain of primary monovalent alcohol, optionally in the presence of a diamine, wherein the long chain alcohol has at least 20 carbon atoms, and preferably 24 or more carbon atoms. The liquid polymerized fatty acid is esterified with the monovalent alcohol to provide a diester which is a solid at room temperature and has a melting point of less than about 150°C. The diester can be formulated with a colorant and/or an image forming material, to provide an ink for the hot melt printing, such as hot melt inkjet printing, gravure printing, or intaglio printing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a hot melt ink, its components, and a printing method using such an ink.

BACKGROUND OF THE INVENTION Hot melt inks are characterized by being solid at room temperature and melting at the high temperatures that the hot melt ink imparts to the substrate. Hot melt inks are widely used in ink jet printers and have been proposed for use in intaglio printing and gravure printing.

  Inkjet printing is a well-known process for printing without contacting a substrate such as paper, plastic film, metal foil or the like. In general, inkjet printing ejects a jet of liquid ink through a very small orifice. After jetting, the jet is divided into small droplets of uniform size at a fixed distance from the known orifice as the dispersion distance. The ink droplets travel through the air until they strike the substrate, thereby forming an image on the substrate.

  Various techniques have been developed for directing jet ink in an image fashion from a print head of a printing device to a substrate. In one technique called drop-on-demand, the printhead passes over the substrate and ejects ink droplets only at that location when the ink is desirably placed on the substrate. . The instant dripping technique is commonly used in desktop ink jet printers.

  In contrast, in a process known as continuous stream jet printing, the print head continually ejects ink droplets while passing over the substrate or while the substrate passes the print head. ing. Since the guiding system is located between the print head and the substrate, the ink droplets should not touch the substrate at a specific location on the substrate or the ejected droplets Is directed to one of the recirculation grooves. A typical continuous jet ink jet printer uses ink that can be charged, and the guiding system is an electrostatic field that interacts with the charged ink droplets and directs the ink droplets to the desired location. Continuous jet jet ink printing is more commonly found in industrial printing than desktop printing.

  Jet inks suitable for either instant drop or continuous jet ink jet printing can be classified as either liquid jet inks or hot melt jet inks. Both types of ink typically include both a colorant and a carrier. Here, the carrier is any material that dissolves or suspends the colorant. Liquid jet ink is liquid at room temperature and is typically at about room temperature when stored in the printhead before being ejected. A simple liquid jet ink consists of an aqueous carrier and a water-soluble dye as a colorant. After the liquid jet ink contacts the substrate, the solvent typically evaporates or escapes from the colorant, thereby leaving the colorant visible where the ink first contacts the substrate.

  In contrast, hot melt jet inks are solid at room temperature and are heated to a molten state before being ejected from an inkjet printhead. The molten hot melt ink cools and solidifies upon contact with a substrate, which is typically at room temperature. A simple hot melt ink consists of a wax as a carrier and a pigment or dye as a colorant. All or nearly all components of the hot melt ink remain where the molten ink contacts the substrate. That is, little or no hot melt ink escapes or evaporates.

  The ink composition used for jet ink printing must have certain properties. The ink composition provides a consistent dispersion length, droplet viscosity, and a constant liquid, at least in continuous jet jet printing, under a specific set of conditions used during the jet ink printing process. It is highly desirable to represent the charge of the drop. In order to meet these requirements, the jet ink composition must have stable viscosity and resistance characteristics and must not dry over time.

  One of the major problems faced by liquid jet inks is that the inks contain significant amounts of water and / or organic solvents. Since the water and / or the organic solvent evaporates when allowed to stand, these ink compositions dry and solidify. As a result, the orifice of the print head is blocked. A further problem is that loss of volatile solvent increases the viscosity of the ink, thereby substantially changing the performance of the ink. Also, porous substrates such as paper tend to wrinkle and / or distort when printed using a large amount of liquid jet ink. Furthermore, organic solvents present in the liquid jet ink can evaporate after contacting the substrate, which can cause health problems for nearby people.

  Another problem associated with the presence of volatile solvents in liquid jet inks is that the solvent bleeds the colorant inside the printed substrate, which is typically porous, resulting in reduced printing resolution. It is to become scarce. Porous substrates with special coatings can overcome this problem, but such special substrates are expensive and work well on “plain paper” or standard uncoated sheets, for example It is not usually necessary for other types of printing such as copy printing. In at least office settings, it is highly desirable that all printing, including ink jet printing, be done on “plain paper” or standard transparency.

  Hot melt inks offer many advantages over liquid inks. For example, when liquid ink is used to place a colorant on a porous substrate, the colorant tends to be carried inside the substrate as the liquid carrier enters the substrate. This causes a reduction in printing density and a slight reduction in printing resolution. However, the rapid solidification of the hot melt ink fixes the colorant to the substrate surface and correspondingly increases the printing density and resolution. A further advantage is that there is little or no wrinkling associated with hot melt ink printing. This advantage is in sharp contrast to the situation of printing liquid ink. Yet another advantage is that hot melt inks are easier to transport than liquid inks without spilling.

  For several reasons, the adhesion of the colorant to the substrate can also be excellent in hot melt printing. For example, all carriers in a hot melt ink do not evaporate or escape from the colorant as occurs in printing with liquid ink, but remain on the surface of the substrate printed with the colorant, so This is more effective in assisting the fixing of the colorant to the substrate surface. Also, a solid carrier at room temperature naturally has better fixing properties than a liquid carrier.

  Looking specifically at jet ink printing, hot melt inks offer the advantage of having essentially no volatile components. Therefore, there is no component evaporation in hot melt inks, and therefore there are no health risks associated with ink viscosity changes, solidification, and solvent evaporation corresponding to the component evaporation seen with liquid inks.

To a large extent, the characteristics of the carrier determine the characteristics of the jet ink. The prior art discloses several materials that can be used in hot melt jet inks as carriers, sometimes called vehicles, binders, or solid organic solvents. Patent Document 1, diesters of sebacic acid (a solid linear (solid linear), C ₁₀ dicarboxylic acid) discloses the use of paraffinic alcohols having and 12 or fewer carbon. Patent document 2 discloses the use of natural wax. _U.S. Patent _{No. 6,057,033} discloses the use of _C20-24 acids or alcohols. U.S. Patent No. 6,099,086 discloses the use of aromatic sulfonamides. Patent document 5 discloses the use of short chain polyamides. U.S. Patent No. 6,057,032 discloses the use of ethyl ester of stearic acid (solid linear, _C18 carboxylic acid). U.S. Patent No. 6,099,077 discloses the use of tall oil rosin. The above is an illustration of prior art relating to hot melt ink carriers.

  U.S. Patent No. 6,099,077 discloses the preparation of an ester wax. This ester wax is a mixture of a solid aliphatic monocarboxylic acid and a solid aliphatic dicarboxylic acid reacted with a solid aliphatic wax alcohol (obtained by oxidation of a natural or synthetic hydrocarbon having a freezing point of about 70 ° C.) (Prepared by oxidation of paraffin and / or montan wax). This wax ester is said to be useful for floor polishing.

U.S. Patent No. 6,057,031 discloses high molecular weight esters prepared by reacting a primary branched alcohol having a minimum of 28 carbon atoms with a polymeric fatty acid. This ester is a liquid at room temperature and is therefore unsuitable for hot melt inks, but is useful as a lubricant, release agent, plasticizer, solvent, or modifier additive for such compositions. It is said that there is.
U.S. Pat.No. 3,653,932 U.S. Pat.No. 4,390,369 U.S. Pat.No. 4,659,383 U.S. Pat.No. 4,820,346 U.S. Pat.No. 4,830,671 U.S. Pat.No. 5,151,120 U.S. Pat.No. 5,354,368 British Patent No. 909,363 International Publication No. 86/00300 Pamphlet

  Despite considerable research in the field of carriers for hot melt inks, there remains an excellent carrier material useful for hot melt inks and inks having such carrier materials. is needed.

SUMMARY OF THE INVENTION The present invention relates to solid diesters prepared by reacting about 2 equivalents of liquid polymerized fatty acid with about x equivalents of C _{20 +} monohydric linear alcohol and about y equivalents of diamine. Here, x + y is equal to about 2, and y is 0 to about 1.

The present invention also relates to a process for preparing a solid diester in which about 2 equivalents of liquid polymerized fatty acid is reacted with about x equivalents of C _{20 +} monovalent linear primary alcohol and about y equivalents of diamine. Here, x + y is equal to about 2, and y is 0 to about 1.

  Another aspect of the invention relates to a hot melt ink composition comprising an imaging component and a solid diester as described above.

  Yet another aspect of the present invention is a method of jet printing. The method comprises the steps of mixing an imaging component with the solid diester, thereby preparing a hot melt ink, and melting the hot melt ink inside a print head designed for hot melt printing. And jetting the molten hot melt ink from the print head onto the substrate.

  A further aspect of the invention is a method of gravure printing and intaglio printing. This method comprises the steps of mixing an imaging component with the solid diester described above, thereby preparing a hot melt ink, melting the hot melt ink to prepare a molten ink, and melting the gravure or intaglio printing plate with the molten ink. Providing a printing plate having a molten ink on the plate, and then contacting the printing plate having the molten ink on the plate with the substrate and transferring the image from the printing plate to the substrate. Include.

According to the present invention, the following is provided to achieve the above object.
(Item 1) Prepared by reacting about 2 equivalents of liquid polymerized fatty acid with about x equivalents of C _{20 +} monovalent linear primary alcohol and about y equivalents of diamine, where x + y is equal to about 2 and y A solid diester in which is from 0 to about 1.
(Item 2) The diester according to Item 1, which has a melting point of about 40 ° C to about 150 ° C.
(Item 3) The diester according to Item 1, having a melting point of about 60 ° C to about 130 ° C.
(Item 4) The diester of item 1, having a viscosity of less than about 300 cP at 150 ° C.
(Item 5) The diester of item 1, having a viscosity of less than about 100 cP at 130 ° C.
(Item 6) The diester of item 1, wherein the diester has an acid value of less than about 20.
(Item 7) The diester according to Item 1, wherein the polymerized fatty acid has an acid value of about 180 to about 200.
(Item 8) The diester according to item 1, wherein the polymerized fatty acid is a hydrogenated polymerized fatty acid.
9. The diester of claim 1, wherein the polymerized fatty acid comprises less than about 10 weight percent trimer acid and greater than about 90 weight percent dimer acid.
(Item 10) the diamine has a molecular formula of H ₂ NR-NH _2, R is selected from C ₂ ~ about C ₃₆ hydrocarbons and C ₂ ~ about C ₃₆ poly (alkyleneoxy), according to claim 1 Diester.
(Item 11) The diester according to item 1, wherein the diamine is selected from the group consisting of ethylenediamine, 1,6-hexanediamine, and 1,10-decanediamine.
(Item 12) The diester of item 1, wherein the monohydric alcohol has from 20 to about 26 carbon atoms.
(Item 13) The diester according to item 1, wherein the monohydric alcohol is a mixture of monohydric alcohols, and the mixture has a hydroxyl value of about 60 to about 180.
(Item 14) The diester according to item 13, wherein the mixture has a hydroxyl value of about 70 to 130.
(Item 15) The diester according to Item 1, wherein y is less than about 0.33.
(Item 16) The diester according to item 1, wherein y is 0.
(Item 17) A hot melt ink composition comprising an image forming component and the diester according to item 1.
(Item 18) The hot melt ink composition according to item 17, wherein the image forming component is a colorant.
(Item 19) The hot melt ink composition according to item 17, having a viscosity of about 1 cP to about 50 cP at a temperature of about 75 ° C. to about 175 ° C.
(Item 20) The hot melt ink composition according to item 17, having a viscosity of about 5 cP to about 15 cP at a temperature of about 110 ° C to about 130 ° C.
(Item 21) A step of preparing a hot melt ink by mixing an image forming component with the diester described in Item 1, and a step of storing the hot melt ink in a molten state inside a print head designed for hot melt printing And a step of ejecting the molten hot melt ink from the print head onto the substrate.
(Item 22) A step of preparing a hot melt ink by mixing an image forming component with the diester of Item 1, a step of preparing a molten ink by melting the hot melt ink, and a gravure printing plate or an intaglio printing plate Contacting the molten ink to provide a printing plate having the molten ink thereon, and then contacting the printing plate having the molten ink thereon with a substrate from the printing plate to the substrate. And a step of transferring an image to the printing method.
(Item 23) comprising reacting about 2 equivalents of liquid polymerized fatty acid with about x equivalents of C _{20 +} monovalent linear primary alcohol and about y equivalents of diamine, wherein x + y is equal to about 2 and y A process for preparing a solid diester wherein is from 0 to about 1.
(Item 24) The process according to item 23, wherein y is 0.
25. The diamine has a molecular formula of H ₂ NR—NH ₂ , R is selected from C ₂ to about C ₃₆ hydrocarbons and C ₂ to about C ₃₆ poly (alkyleneoxy), and the monohydric alcohol is 24. The process of item 23, having 20 to about 26 carbon atoms.

The present invention relates to solid diesters useful as components of hot melt inks, and more particularly to hot melt inks for ink jet printing, intaglio printing, and gravure printing. This diester is prepared by esterifying a liquid polymerized fatty acid, mainly a dicarboxylic acid (also known as a dibasic acid), with a long-chain linear monohydric alcohol, optionally in the presence of a diamine. Such a reaction of a dicarboxylic acid with a monohydric alcohol provides a diester that is solid at room temperature and has a melting point below about 150 ° C. This diester can be formulated with colorants and / or other imaging components to provide inks for hot melt printing.

The polymerized fatty acids used to form the solid diesters of the present invention are well known and commercially long-lived materials and need not be described in great detail. Polymerized fatty acids are typically formed by heating long chain unsaturated fatty acids such as _C18 monocarboxylic acids to about 200 to about 250 ° C. in the presence of a clay catalyst so that the fatty acids polymerize. . The product is typically a dimer acid formed by dimerization of fatty acids, i.e., C ₃₆ dicarboxylic acids and trimer acids formed by trimerization of the fatty acid, i.e., C ₅₄ tricarboxylic Including acid. Polymerized fatty acids are typically a mixture of structures in which the individual dimer acids can be saturated, unsaturated, cyclic, acyclic, and the like. A more detailed discussion of fatty acid polymerizations can be found in, e.g., U.S. Pat.No. 3,157,681, and NavalStores-Production, Chemistry and Utilization, DF Zinkel and J. Russel (eds.), Pulp. Chem. Assoc. Inc., 1989, No. See Chapter 23.

  Fatty acid polymerization forms much more dimer acid than trimer acid, so even if trimer acid and even higher polymerization products are present with dimer acid. A trader can often refer to polymerized fatty acids as dimer acids. Preferably, the polymerized fatty acid comprises less than about 10 weight percent trimer acid based on the total weight of the polymerized fatty acid, and the dimer acid comprises at least about 90 weight percent of the polymerized fatty acid. More preferably, the dimer acid essentially comprises the entire polymerized fatty acid.

  Typical unsaturated fatty acids used to form polymerized fatty acids include oleic acid, linoleic acid, linolenic acid, and the like. Tall oil fatty acid is a mixture containing long-chain unsaturated fatty acid obtained as a by-product of wood pulp processing, and is suitable for the preparation of polymerized fatty acid useful in the present invention. While tall oil fatty acids are suitable long chain fatty acid sources, polymerized fatty acids can alternatively be prepared by polymerization of unsaturated fatty acids from other sources (eg soybean or rape).

  Tall oil fatty acids typically contain some resin acid. Therefore, the polymerization of tall oil fatty acids can be formed by combining dimer acids with impurities such as resin acids, dimerized resin acids, and decarboxylic acid resin acids. These impurities can be present in the polymerized fatty acids useful in the present invention. Typical acid values of polymerized fatty acids useful in the present invention are on the order of about 180 to about 200.

  Polymerized fatty acids useful in the present invention are liquids, regardless of whether their components, such as trimer acid and / or resin acid dimer, are solid or semi-solid. However, the combination with any component present with the dimer acid is liquid at 25 ° C.

  The polymerized fatty acids of the present invention can be hydrogenated prior to the esterification reaction. Alternatively, the product of the esterification reaction can be hydrogenated. In any case, hydrogenation tends to provide a slightly higher melting point for the diester and tends to give the diester a somewhat higher oxidative stability.

  Polymerized fatty acids, dimer acids, and hydrogenated variants thereof can be obtained from many vendors. For example, Union Camp Corporation (Wayne NJ) sells polymerized fatty acids under the UNIDIME® trademark.

The diester of the present invention is a reaction product of a polymerized fatty acid and a long-chain linear monohydric alcohol as described above. Long chain alcohols useful in the present invention have at least 20 carbon atoms. The long chain alcohol typically does not have more than about 60 carbon atoms, but may have 30, 40, or more carbon atoms. The symbol C ₂₀₊ means herein that the monohydric alcohol useful in the present invention has at least 20 carbon atoms, and optionally more than 20 carbon atoms.

C ₂₀₊ monohydric alcohols useful in the present invention are solid at 25 ° C. Suitably, the C ₂₀₊ monohydric alcohol is a primary saturated linear alcohol having the molecular formula C _n H _{2n + 2} O, where n is at least 20.

The C ₂₀₊ monohydric alcohol is selected such that the diester formed from the alcohol is a solid having a melting point of at least about 40 ° C., preferably at least about 50 ° C., more preferably at least about 60 ° C. . In addition, the monohydric alcohol is selected such that the diester prepared from the alcohol has a melting point below about 150 ° C, preferably below about 140 ° C, more preferably below about 130 ° C.

  Suitable monohydric linear alcohols useful in preparing the compositions of the present invention can be essentially pure monohydric alcohols having at least about 20 carbon atoms. Preferably, this essentially pure monohydric alcohol is at least about 90 weight percent of a single molecular structure, more preferably at least about 95 weight percent of a single molecular structure. Essentially pure monohydric alcohols having 20 to about 26 carbon atoms are well suited for use in the present invention. Preferably, this essentially pure monohydric alcohol has at least about 22 carbon atoms, more preferably at least about 24 carbon atoms. The number of carbon atoms of all impurities present in this essentially pure monohydric alcohol is preferably greater than about 10, more preferably greater than about 14 and even more preferably greater than about 18. Many.

  Essentially pure monohydric linear alcohols with more than 20 carbon atoms include many, including Aldrich Chemical Co., Inc. (Milwaukee, WI) and M. Michel and Company, Inc. (New York, NY) Marketed by A suitable pure monohydric alcohol is behenyl alcohol, commercially available as Cachalot® from M. Michel and Company, Inc. (New York, NY).

  Alternatively, the monohydric linear alcohol can be a monohydric alcohol mixture as long as the reaction product of the dicarboxylic acid and the monohydric alcohol mixture is a solid, ie, has a melting point of at least about room temperature. Preferably, at least about 90% of the monohydric alcohol in the monohydric alcohol mixture has at least about 20 carbon atoms, more preferably at least about 24 carbon atoms. The remaining 10% of impurities in the monohydric alcohol mixture can have fewer than 20 carbon atoms as long as the monohydric alcohol mixture has a hydroxyl number of at least about 60, preferably from about 70 to about 130.

Among many other techniques, vapor pressure osmometry (VPO) can be used to characterize the number average molecular weight of an alcohol mixture. Mixtures of monohydric alcohols useful in the present invention have a number average molecular weight of about 200 to about 800, preferably about 300 to about 600, depending on the VPO. Pure C ₂₂ monohydric linear alcohol has a number average molecular weight of 326 by VPO.

  Suitable alcohol mixtures are commercially available, for example, from Petrolite Corporation (Tulsa, OK) under the trademark UNILIN®.

Monohydric alcohols have linear alkyl groups, whether present as essentially pure alcohols or present in mixtures of monohydric alcohols. Exemplary alcohols useful in the present invention include 1-eicosanol (C ₂₀ ), 1-docosanol (C ₂₂ , also known as behenyl alcohol), dotriacontanol (C ₃₂ ), tetratriacontanol (C _34), penta triacontanol (C _35), tetra con ethanol (C _40), tetra Acon ethanol (C _44), de penta Acon ethanol (C _54), tetra-hexa Acon ethanol (C _64), de hexa Acon pentanol (C ₇₂ ) and the like are included.

  A diamine can be added to the reaction mixture comprising polymerized fatty acid and monohydric alcohol. As used herein, the term diamine refers to an organic molecule having only two reactive amine groups. If a diamine is present, the diamine allows the formation of an amide diester. However, the amount of diamine present in the reaction mixture of polymerized fatty acid and monohydric alcohol must be very small. Otherwise, the melt viscosity of the resulting amide diester will be too high. Therefore, only about 50% of the total reaction equivalent of the mixture of diamine and monohydric alcohol can be contributed by the diamine component.

  In other words, the reaction mixture comprises about 2 equivalents of polymerized fatty acid, about x equivalents of monohydric alcohol, and about y equivalents of diamine, so that an essentially neutral product is formed, x + y = about 2. If so, y is less than about 1. Preferably, y is less than about 0.33 so that only one third of the equivalents that are reactive with the polymerized fatty acid arise from the diamine component. More preferably, y is less than 0.25, even more preferably y is equal to 0. When y is 0, the reaction product does not contain an amide bond. When 2 equivalents of dibasic acid are used in the reaction, x + y need not be exactly equal to 2, but preferably the product is essentially neutral, ie less than about 20, preferably about 10 Has a lower acid number.

  The optional diamine component has only two reactive amine groups, which are preferably primary amine groups. The reactive amine group combines with organic components formed from carbon, hydrogen, and optionally oxygen atoms. Here, the organic component has from 2 to about 36 carbon atoms. Ethylene diamine is an exemplary diamine having 2 carbon atoms, whereas dimeric diamine is an exemplary diamine having 36 carbon atoms. The carbon skeleton of the diamine component can be saturated or unsaturated, for example, linear alkylene in 1,6-hexanediamine (also known as hexamethylenediamine) and 1,12-dodecanediamine, cyclic alkylene in isophoronediamine Or aryl in xylenediamine. JEFFAMINE (R) diamine, or poly (alkyleneoxy) diamine, manufactured by Texaco, Inc. (Houston, TX), also known as polyether diamine, contains both carbon and oxygen in the organic component to which the amine group is attached. An exemplary diamine having:

  Suitable diamines such as 1,6-hexanediamine, ethylenediamine and 1,10-decanediamine have from 2 to about 12 carbon atoms.

  To prepare the solid diesters of the present invention, the polymerized fatty acid, monohydric alcohol, and optionally a diamine component can be combined and the product mixture can be heated. Any order of combination is suitable, and the heating rate is not particularly important. The final heating temperature is suitably about 200 ° C to about 250 ° C. The progress of the reaction is monitored by taking samples and measuring the acid number and melt viscosity of those samples.

  During heating, water vapor is released as esterification and, if necessary, amidation reactions occur. Preferably, water vapor is condensed and removed from the reaction mixture as soon as it is formed, thereby completing the reaction. A Dean-Stark trap is suitably used for this purpose. Alternatively, the water vapor is removed by applying a moderate vacuum of about 20 to about 200 mtorr.

  A catalyst can be used to speed up the esterification or ester / amidation reaction. Suitable catalysts here are well known in the art, such as sulfuric acid, phosphoric acid and other inorganic acids, metal hydroxides and alkoxides such as tin oxide and isopropoxide titanate, tin or zinc salts and the like And a divalent metal salt. When present, the catalyst is used in small amounts, for example, less than about 5% by weight of the total mass of the reaction mixture, preferably less than about 2%, more preferably less than about 1% of the total mass of the reaction mixture. Should do. An unnecessarily high amount of catalyst increases the cost of preparing the diester or amide diester, and often leaves a residue that can be detrimental to the environment in which the hot melt ink is located, such as the printhead.

  Diesters have melting and melt viscosity properties that make them well suited as components of hot melt inks, particularly jet inks. Thus, the diester is a solid at room temperature and may have a melting point of about 40 ° C to about 150 ° C, preferably about 50 ° C to about 140 ° C, more preferably about 60 ° C to about 130 ° C. The diester further has a melt viscosity of less than about 300 centipoise (cP) at 150 ° C., preferably less than about 200 cP at 140 ° C., more preferably less than about 100 cP at 130 ° C.

  Preferred diesters of the present invention are at least partially transparent and therefore do not interfere with, smudge or obscure the appearance of colorants or other imaging components in the ink. Furthermore, suitable diesters are hard, not oily and non-tacky.

  Another aspect of the present invention is a hot melt ink composition comprising an imaging component and a diester as described above. An imaging component is a material that can be detected or observed by any means. Colorants are suitable imaging components, where they can be detected visually by the human eye or by an optical character reader. Both dyes and pigments are suitable colorants, and an extensive list of specific dyes and pigments suitable for use in the hot melt inks of the present invention is described in both US Pat. Nos. 5,286,288 and 5,122,187. Has been. The entire disclosures of these two patents are incorporated herein by reference.

  Alternatively, the imaging component can be a magnetic material that can be scanned by a suitable reader, or a fluorescent material that can be detected upon exposure to light of a particular wavelength. In rare cases, the carrier itself may serve as the imaging component, but more typically the carrier functions primarily to suspend and disperse the imaging component at elevated temperatures and after printing the image A transparent material that helps to fix the forming component to the substrate.

  The carrier typically comprises about 0.5 to about 97 weight percent of the hot melt ink composition, preferably about 80 to about 97 weight percent of the hot melt ink composition. The imaging component typically comprises from about 0.1 to about 3 weight percent, preferably from about 0.3 to about 2 weight percent of the hot melt ink composition.

  The hot melt ink composition of the present invention may contain components in addition to the colorant and the diester. For example, when hot melt ink is used for continuous jet ink printing, the ink may include an electrolyte. By including an electrolyte, the hot melt ink can be made to carry a charge by adjusting the electrostatic field through which the charged ink particles must pass, and the charged hot melt ink droplets can be printed. Can be directed to either the substrate or the recirculation groove. Suitable electrolytes for the hot melt ink compositions of the present invention are inorganic salts such as those disclosed, for example, in US Pat. No. 5,286,288. When the electrolyte is an inorganic salt, electrolyte solvates and dissociative compounds as well disclosed in US Pat. No. 5,286,288 are preferably present in the hot melt ink composition.

  Other ingredients that may be present in the hot melt ink composition of the present invention include corrosion inhibitors, biocides, plasticizers, tackifiers, surfactants, dispersions, antioxidants, rheology modifiers, and One or more of the UV stabilizers are included.

  The hot melt ink composition of the present invention generally simply combines the desired ingredients to form a mixture and the mixture is heated with stirring to form a molten homogeneous composition that is a hot melt ink composition. Can be prepared. Typically, a temperature of about 90 ° C. to about 150 ° C. is suitable to achieve a uniform composition after stirring for about 5 seconds to about 10 minutes. It is also possible to melt one component of the ink, such as the carrier, and then add the other components with stirring. If a pigment is included in the hot melt ink composition, it may be necessary to grind the mixture of components to provide a uniform dispersion of the pigment in the ink. Grinding may suitably be accomplished by a ball mill or an atritor.

  As used herein, the term “hot melt ink” refers to an ink that is solid at room temperature and liquid at the operating temperature of a printer that uses hot melt ink. A typical printer for hot melt inks heats the ink to about 110 ° C to about 130 ° C. Therefore, the hot melt ink of the present invention has a viscosity of about 1 centipoise (cP) to about 50 cP at a temperature of about 75 ° C. to about 175 ° C., more preferably at a temperature of about 90 ° C. to about 150 ° C. It has a viscosity of about 2 cP to about 20 cP, and even more preferably has a viscosity of about 5 cP to about 15 cP at a temperature of about 110 ° C to about 130 ° C.

  The hot melt inks of the present invention can be used to print on a wide variety of substrates that can be porous or non-porous. Exemplary substrates include plastic, plastic laminate, glass, metal, paper, wood, and the like. This ink can be used in instant drop printers and continuous ink jet printers. These printers are commercially available from many vendors.

  Hot melt inks can also be used for gravure and intaglio printing. To achieve such printing using hot melt ink, the hot melt ink as described above is melted and the melted ink is stored in a reservoir. The printing plate is typically warmed above or about the same temperature as the hot melt ink, and the printing plate is then contacted with the pooled molten hot melt ink. In this way, the melted ink is transferred to the gravure or intaglio printing plate in essentially the same manner as current methods for transferring liquid ink to the printing plate.

  A printing plate having melted hot melt ink thereon is then contacted with the substrate in order to transfer the ink to the substrate in an imagewise fashion. The substrate is typically at room temperature and immediately causes the hot melt ink to cool, thereby immobilizing the ink to the substrate.

  The following examples are set forth as a means of illustrating the invention and are not to be considered as limiting the invention.

Example 1
Preparation of di (C ₃₈ ) alkyl dimer acid salt
21.4g EMPOL (R) 1008 dimer acid (HenkelCorp., Emery Group, Cincinnati, OH, about 72 meq acid group) and 50.7g UNILIN (R) 550 alcohol (Petrolite Corporation, Polymers Division, Tulsa, OK , Vapor pressure osmometry (VPO) number average molecular weight of 550, an alcohol mixture having an estimated functional group purity of 85% and a hydroxyl value of 76; 69 meq hydroxyl group) is heated to 220-225 ° C and held for 3 hours , Thereby forming a hard, brittle, off-white, non-sticky, nearly opaque solid. The softening point of this solid was 99 ° C., and the viscosity was 21 cP at 130 ° C.

Example 2
Preparation of di (C ₃₈ ) alkyl dimer salt modified with 1,6-hexanediamine
53.1 g EMPOL® 1008 dimer acid (about 180 meq acid), 94.2 g UNILIN® 550 alcohol (128 meq hydroxyl group), 2,7 g 1,6-hexanediamine (hexamethylene) HMDA, also known as diamine, HMDA, Aldrich Chemical, Milwaukee, WI, 46 meq amine) and heated to 220-225 ° C and held for 3 hours, thereby stiff, brittle, tan, non-sticky, translucent Formed a solid. The softening point of this solid was 103 ° C., and the viscosity was 28 cP at 130 ° C.

Example 3
Preparation of di (C ₂₆ ) alkyl dimer salt modified with 1,6-hexanediamine
29.5 g EMPOL® 1008 dimer acid (about 104 meq acid groups) and 22.5 g UNILIN® 350 alcohol (375 vapor pressure osmometry (VPO) number average molecular weight and 85% estimated sensory function) Alcohol mixture with base purity and hydroxyl value 129; 52 meq hydroxyl) and 3.0 g HMDA (52 meq amine) heated to 220-225 ° C. and held for 3 hours, thereby being slightly soft, A flexible, tan, non-tacky, translucent solid was formed. This solid had an acid number of less than 9, a softening point of 77 ° C, and a viscosity of 45 cP at 130 ° C.

Example 4
28.3 g EMPOL® 1008 dimer acid (about 96 meq acid groups), 19.4 g Cachalot BE (1-docosanol, M. Michel and Company, New York, NY, 58 meq.), 2.3 g HMDA (38 meq amine) was heated to 220-225 ° C. and held for 3 hours, thereby forming a translucent, hard solid. The softening point of this solid was 73 ° C., and the viscosity was 33 cP at 130 ° C.

Comparative Example 1
Stearyl alcohol (hydroxyl of Aldrich Chemical Co., Milwaukee, WI, 15.02 g, 56 meg), dimer acid (EMPOL® 1008, 31.76 g, 112 meq acid) and HMDA (3.23 g, 56 meq) The mixture is heated to 223-228 ° C. for 3 hours with a gentle sweep of nitrogen. The product cooled to room temperature was a clear, almost colorless, soft solid. The solid handle contained fat, had a softening point of 75 ° C. and a viscosity of 53 cP at 130 ° C. This material is unsuitable for use in jet inks due to their physical properties. Because this material is too soft to have adequate frictional resistance, it contains a lot of fat, it cannot have proper adhesion, and it is very hard, so a film-like substrate Because it cannot be moistened.

  It will be understood by those skilled in the art that changes can be made to the above-described embodiments without departing from the broad inventive concept of the above-described embodiments. Accordingly, it is to be understood that the invention is not limited to the particular embodiments disclosed, but is intended to encompass modifications within the spirit and scope of the invention as defined by the appended claims.

Claims (1)

Prepared by reacting about 2 equivalents of liquid polymerized fatty acid with about x equivalents of C _{20 +} monovalent linear primary alcohol and about y equivalents of diamine, where x + y is equal to about 2 and y is from 0 to about 1, a solid diester.