MXPA06004600A - Novel wax for reducing mar and abrasion in inks and coatings - Google Patents

Abstract

Waxes prepared from hydrogenated plant oils, such as castor and soybean, are formulated into aqueous ink and paper coating compositions. Ink compositions comprising these waxes and evaluated for their resistance to mar and abrasion achieved rub resistance and slip performance comparable to compositions utilizing conventional wax additives, which are generally derived from petroleum. The waxes in the inventive compositions have a low iodine value (ranging from approximately 2 to approximately 5), and a melting point between approximately 120 degrees to approximately 190 degrees F (Mettler Drop Point). These naturally derived waxes are used as an alternative to petroleum and synthetically derived waxes in the manufacture of inks and coatings for paper and cellulosic products.

Description

NEW WAX TO REDUCE USUAL WEAR AND ABRASION IN INKS AND COATINGS FIELD OF THE INVENTION One embodiment of the present invention is an ink composition which includes a highly hydrogenated wax which is prepared from oils of hydrogenated plants, such as castor bean and soybean . These waxes, when used as additives in paper and ink coating formulations, impart properties of conventional anti-wear, anti-rub, or anti-slip ink to the ink or coating. The compositions containing these waxes protect the printed and coated articles against abrasion, embrittlement or staining while maintaining the sliding properties when the ink or coating is subjected to scratching forces that may occur during shipping, or handling of a coated or coated article. printed. The waxes used have a low iodine value (ranging from about 2 to about 5), and a melting point between about 120 degrees to about 190 degrees F (48.4-86.9 ° C) (Mettler Drip Point). The wax includes a triglyceride whose fatty acids are predominantly stearic acid (C? 8). BACKGROUND OF THE INVENTION Inks and coatings are used to print text and images on a variety of different surfaces (or Ref. 171803 substrates), ranging from cellulosic articles such as paper and corrugated cardboard, plastic articles and films, metals, to articles of clothing. The ink is generally applied to a portion of the substrate to produce a detailed image such as letters or an image. A coating is generally applied uniformly on a complete substrate as a continuous film. Inks and coatings that are subject to rubbing and scratches, whether in transit, storage or use, may be scratched with lines and, in the case of text, become difficult to read, or lose the expected image quality. the end users. The final use of the ink has a role in the determination of its formulation, because certain properties are more desirable in one type of ink than another. Various types of ink are used in processes such as high speed newspaper printing, gravure inks, flexography, thermal offset, thermofixing, letterpress, screen printing, spraying, brush application, or the like. For the purpose of the present invention, the term flexographic ink should refer to the ink used in flexography, flexography being defined as "... use raised rubber or photopolymer plates (for printing), and requires preparation shorter than typographic printing or offset printing ... Flexography is used to print milk cartons, narrow-mesh labels, flexible packaging, corrugated cardboard and paperback books. " (A. Glassman, 1985, Printing Fundamentals, TAPPI Press, page 322). In addition, flexography can be used for printing on other substrates, such as plastic films, sheets, coated and uncoated papers, and cardboard. The additives are often incorporated into inks and coating being mixed and ground in the ink formulation and coating with pigments; added as a part of the final ink mixture; or introduced in other times. The printing inks in particular use such additives, so that the ink does not rub off when the substrate surface is subjected to the normal abrasive forces encountered in use and handling, such as during the handling of paper products, or during the shipment of corrugated cardboard under the wet conditions that accompany the handling of refrigerated or frozen goods, or shipped goods packed in ice. The addition of frequently selected additives also produces improved slip properties. The sliding properties allow other printed pages to contact and rub on the ink or coating without causing the ink to stain. Frequently controlled slippage is desirable for such items as magazines that will be stacked; It may be undesirable to have the stack slid apart. One way to control the slip property is the use of micronized waxes incorporated in the ink or coating. It is speculated that the fundamental mechanism involves some interlacing of the wax particles between the two coated surfaces. The wax is micronized, and dispersed in the formulation to such an extent that it can not be detected by the human eye. The dispersion of the micronized waxes in the formulations also has a lesser effect on the gloss reduction than if the wax were melted in the ink or coating formulation. It is known in the art that micronized waxes can revert to inks and coatings less susceptible to abrasion and also enable slip control. Some waxes used in ink and coating formulations to modify the usual wear abrasion and slip modification are often supplied in powder form. Hard waxes are generally jet milled at a particle size ranging from about 5 to about 15 microns, with the resulting products often being referred to as 'micronized waxes'. These powdered waxes are often difficult to disperse in the ink or coating formulation due to the high surface tension and the need to break apart the agglomerates. To facilitate their dispersion in ink or coating formulations, suppliers of micronized waxes often treat the surface of the powder with surfactants or other dispersion aids, or grind the powder into a paste that is more easily dispersed in the ink or coating formulation. final . The jet milling of wax in micronized particle sizes is an intensive energy process which also generates heat. This process can often cost more than the value of the wax itself. Hard waxes, defined as those that have a hardness of less than 6 dmm (as measured by the needle penetration test for wax hardness) are milled easier than soft waxes, and therefore cost less to micronize them . The melting point of the wax also affects the ability of a wax to be micronized; If the melting point is too low, the heat generated in the jet milling may cause the wax to melt, rendering the process incapable of micronizing the wax. In addition, mechanical chillers for jet mills have been used, but because they increase grinding costs even further, it is generally considered that they are not cost effective. Many commercially available anti-abrasion compounds contain polytetrafluoroethylene ("PTFE") in the form of a micronized powder. PTFE, commercially available from E. I. DuPont, Wilmington, DE and sold under the TEFLON® brand, has a low surface tension that makes it difficult to disperse and requires long mixing times. One compound containing PTFE is Protech 120, sold by Carroll Scientific, Inc. (a division of Lubrizol Corp, Wickliffe, OH) which is described as a high solids virgin PTFE wax compound (approximately 83%), and Used in ink formulations. Polyethylene waxes have also been used as anti-abrasion additives in the ink industry. The ink manufacturer usually incorporates these waxes as dispersions of the wax into resins, generally of the same type with the ink formulations in which they will be incorporated. Murayama, in U.S. Patent No. 3,843,570 discloses a porous material comprising PTEE and having micropores, the material is obtained by polymerization of a monomer capable of forming a thermoplastic resin. The resulting material is suitable with inks and is also printable. United States Patent No. 5,158,606 (Carlick et al.) Describes a printing ink composition with a high degree of rub resistance comprising a dispersion of a pigment in a vehicle containing a C7-C40 oil and a polymer latex emulsified in the dispersion. The inventors state that synthetic waxes, such as polyethylene waxes or PTFE waxes, are the most popular waxes used in the ink industry. They also indicate that the relative cost of PTFE waxes is prohibitively high for applications such as new inks, but where the cost is not of interest, a PTFE wax with petrolatum can be added to the oil / latex ink composition. polymeric Mueller et al. (U.S. Patent No. 5,643,984) discloses a wax composition for the printing ink industry which uses polyethylene waxes and oxidized polyethylene waxes; Fischer-Tropsch waxes; microcrystalline or carnauba waxes in an ink formulation based either on an aromatic or aliphatic solvent. The prior art illustrates the use of petroleum waxes and synthetic waxes to formulate the ink and coating compounds. There is no mention of vegetable derived waxes for use in ink and / or coating formulations, there is still a recognized need and a long feeling to find alternatives to products such as PTFE, expensive synthetic waxes such as microcrystalline waxes, and other waxes of oil that are derived from limited and increasingly scarce natural resources. There is also a recognized and long felt need to use materials in inks and coatings that are considered safe for humans due to the use of ink or coating in the manufacture of plastic and paper containers used to transport and store food products. There is also a recognized and long felt need to use ink materials and / or coatings that are naturally derived and can easily be recycled back into the environment without long-term adverse effects; the goods packaged to the consumer, for example, are known to be difficult to recycle. Therefore, there is a need to employ a wax, which has similar properties of commercially available PTFE, and synthetic or petroleum-derived waxes used in ink and coating formulations. Due to the large volume of waxes consumed in these applications it is also preferred that the compositions are readily available. From a both supply and natural resource point of view, it is preferred that the compositions are obtained from a source that is preferably renewable, such as from plant extracts. There is a need for a wax that is hard and highly fused and can be micronized in cost-effective powder. Since the world's oil supply is finite, and reduced, it is also desirable to have a wax that can be obtained from a renewable source, such as plants, before being petroleum-based. The anti-abrasion properties of the waxes of the present invention are most useful for water-based inks and coatings and are particularly suitable for use in flexographic inks. These waxes are particularly well suited for rendering inks and coatings less susceptible to usual wear and abrasion because they are very hard relative to more conventional petroleum-based waxes and are derived from renewable natural resources. BRIEF DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a wax composition that can be incorporated into the ink and coating formulations. Another object of the present invention is to provide an ink or coating composition, which can be subsequently applied to articles such as paper, cardboard and the like for consumer use and other packaged goods applications. Another object of the present invention is to provide a wax composition that can be incorporated into ink and coating formulations as a substitute for petroleum-derived waxes currently used in such formulations. Another object of the present invention is to provide a wax composition that is easily dispersed in ink and coating formulations. Still another object of the present invention is to provide a wax composition which is then formulated in an ink or coating, and the ink or coating is applied to an article as a barrier or for identification or information, the ink or coating has characteristics of usual anti-wear, anti-abrasion and anti-abrasion performance similar to those of a conventional product currently used for this purpose Still another object of the present invention is to provide a wax composition that can be derived from a renewable resource instead of non-renewable petroleum based compositions. Yet another aspect of the present invention is to provide a wax composition which can be derived from a renewable resource and which can be economically produced. Another object of the present invention is to provide a wax composition for use in ink and coating and for paper coating and to have properties that are generally considered safe by the Food and Drug Administration. Another object of the present invention is to provide an ink additive and anti-rub, anti-abrasion and anti-wear coating conventional for water-based inks and coatings, which is useful to increase its performance properties. The additive of the present invention maintains good gloss and degradation properties in the ink or coating formulations in which it is used.

The waxes used in the present invention meet the stringent requirements of these and other applications. The present inventors have unexpectedly discovered that highly hydrogenated oils such as palm, soy and castor can be converted into a wax that can be effectively used as a substitute for conventional synthetic and petroleum waxes in the formulation of ink compounds and / or adhesives. One embodiment of the present invention comprises a highly hydrogenated vegetable oil (derived from sources such as palm, soybean and castor) which has wax-like properties and can be formulated using conventional means with other components in the manufacture of ink and coating compounds , to produce ink and coating compositions which have characteristics of usual wear and abrasion similar to the ink and coating formulations containing a commercially available micronized wax. The ink compositions comprising the waxes of the invention evaluated for their resistance to usual wear and abrasion achieved friction resistance and sliding performance comparable with conventional wax additives, which are generally petroleum derivatives. The waxes of the invention have a low iodine number (ranging from about 2 to about 5), and a melting point between about 120 degrees to about 190 degrees F (48.4-86.9 ° C) (Mettler Drip Point). The wax includes a triglyceride whose fatty acids are predominantly stearic acid (Ci8). Naturally derived waxes are used as an alternative to synthetic derivatives and petroleum. These waxes have the additional benefit of being soluble under average alkaline conditions. This allows for cleaner and easier recycling of articles prepared using hydrogenated vegetable oil wax against conventional petroleum waxes. This is important in consumer packaged goods where the container is often recycled using hot alkaline water. One embodiment of the present invention is an ink formulation that includes a natural wax. Another embodiment of the present invention is a coating formulation for paper and other cellulose products that includes a natural wax. The product is a highly hydrogenated wax derived from the processing of natural oil that contains products such as soybean, palm, castor and other crops from which the oil can be obtained. Although hydrogenated vegetable oils are widely used in the food industry; Highly hydrogenated vegetable oils, such as those in the embodiments of the present invention, are not widely produced or used due to their limited applications in the food industry. The materials are processed and supplied by Archer Daniels Midland (Decatur IL) designated by its product number 86-197-); Cargill Incorporated (Wayzata, MN) designated by its product number 800mrcs0000u and other sources under a generic name 'hydrogenated soybean oil1. The palm oil wax supplied by Custom Shortenings & Oils (Richmond, VA) was appointed Master Chef Stable Flake-P. Nat Wax 185 is a blend comprising 20% castor wax and 80% soy wax, provided by Marcus Oil and Chemical, Houston, TX (a division of HRD Corp., Houston TX, the assignee of this application). DESCRIPTION OF THE FIGURES Figure 1 is a flow diagram illustrating a process for the manufacture of hydrogenated oils. Figure 2 illustrates the results of the Sutherland Roce Test with an ink formulation that does not contain wax (control formulation). Figure 3 illustrates the results of the Sutherland Roce Test with an ink formulation containing an amount of the Nat 185 wax (mixture of hydrogenated castor oil wax and hydrogenated soy wax). Figure 4 illustrates the results of the Sutherland Roce Test with an ink formulation containing a quantity of Shamrock wax S-394 N5T.

DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention is a wax composition, derived from compounds of plant origin, which can be used as an alternative to oil derived wax (waxes derived from both paraffin and synthetic ethylene) in the formulation of ink and coatings which are subsequently used to print and coat various articles, yet the composition produces usual wear and abrasion properties similar to inks and coatings containing synthetic waxes or petroleum waxes. Synthetic and naturally occurring waxes are widely used in a broad cross section of industries including, but not limited to, the chemical, cosmetic, food preparation, personal hygiene, pharmaceutical and printing industries. The term wax is used to denote a broad class of wax and organic ester compounds, which include a variety of chemical structures and exhibit a wide range of melting temperatures. Frequently, the same compound can refer to either a "wax", "fat" or an "oil" depending on the ambient temperature, the chain lengths of the esterified fatty acids, and their degree of saturation or unsaturation. Generally, the greater the degree of saturation and the shorter the chain length of the esterified fatty acids, the higher the melting point of the compound. Regardless of the type of choice, the choice of a wax for a particular application is often determined by whether it is a liquid or solid at the temperature of the product with which it is used. Among the factors that determine whether a wax is a liquid or a solid at a given temperature are properties such as the degree of saturation or unsaturation of the components of the wax, mainly the fatty acids, and a property such as the number of iodine, or iodine index "IY"). The iodine value measures the amount of iodine absorbed in a given time by a compound or mixture, and the IY is therefore a measure of the unsaturation, or number of double bonds, in this compound or mixture. Generally, the greater the degree of saturation and the longer the chain length of the esterified fatty acids, the higher the melting point. Similarly, the lower the iodine value of the compound, the harder it is, and the more solid it will be at a particular temperature. The term "triglyceride" will refer to fatty acid esters of glycerol. Within the context of the present specification, the term "free fatty acid" will refer to a fatty acid that is not covalently bound through an ester bond to another molecule; the term "fatty acid component" will be used to describe a fatty acid which is covalently linked through an ester linkage to another molecule, such as glycerol. Waxes can be obtained from a number of natural sources, among which are petroleum products and plant extracts. Petroleum and plant extracts are complex mixtures, and the purification steps are often required to obtain waxes from them. Frequently it is necessary to extensively purify and wax-change a wax to make it useful for a given purpose. Despite such efforts at modification, many physical characteristics of the waxes still prevent them from being used satisfactorily or require extensive, and often costly, additional treatments to be undertaken. Many commercially used triglycerides and free fatty acids are preferably obtained from plant sources, including canola, carnauba, castor oil, cottonseed, corn, cranberry, palm, soybean and sunflower oils, and are used after being refined by known processes. those skilled in the art. For example, plant triglycerides can be obtained by solvent extraction of plant biomass using aliphatic solvents. Subsequent additional purification may involve distillation, fractional crystallization, degumming, bleaching and steam distillation. The triglycerides obtained are partially or totally hydrogenated. In addition, the fatty acids can be obtained by hydrolysis of natural triglycerides (eg, alkaline hydrolysis followed by purification methods known in the art, including distillation and steam distillation) or by synthesis of petrochemical fatty alcohols. Free fatty acids and triglycerides can be obtained in addition to commercial sources, such as Archer Daniels Midland Co. , Cargill, Central Soya and others. As used in embodiments of the present invention, the free fatty acids and fatty acid components of the triglycerides have various chain lengths, and are saturated. The properties of the wax, such as melting point, vary as a function of the chain length and degree of saturation of the free fatty acids and the fatty acid components. When the degree of saturation decreases, the melting point decreases, similarly, when the chain length of the fatty acids decreases, the melting point decreases. Preferred free fatty acids are saturated fatty acids, such as palmitic acid, and other saturated fatty acids having larger carbon chain lengths, such as arachidic acid and behenic acid. In addition, stearic acid is preferred. The vegetable oils or animal fats can be hydrogenated in a synthetic manner, using methods known to those skilled in the art, to have low or very low iodine levels. Fats naturally composed primarily of saturated triglycerides (such as palm oil or fractionated fats) can be used alone or in blend formulations with usual wear and abrasions / laminates to achieve improved water tolerance for composite materials. Saturated triglycerides having a low iodine number (a range of iodine values of about 0-70 with 0-30 preferred) can be produced by hydrogenation of a commercial oil, such as soybean oil, soybean stearin, stearin, castor, corn, cottonseed, rapeseed, canola, sunflower, palm, palm seed, coconut, blueberry, flaxseed, peanut, fish oil and cellulosic bleach resins; or fats, such as animal fats, including lard and tallow, and mixtures thereof. These oils can also be produced from genetically engineered plants to obtain lower IV oil with a high percentage of fatty acids. Fatty acids are commonly fractionated by a process known as "frigelization", where the mixture is cooled for a sufficiently long period of time to allow the harder fractions of the fats to be crystallized. This cooling is followed by filtration, with the harder fractions that are retained in a filter cake. These harder fractions have a lower iodine value and, therefore, a melting point that is higher than the melting point of the fat from which it has been separated. Accordingly, the frigelization can be used as a source for lower IV fats. The process of frigelization is generally used to fraction animal fat, and therefore can produce a variety of fractions of animal fat, which have different iodine levels and, consequently, different chemical properties. These fractions can be mixed with fatty acids and free fatty acids obtained from other sources, such as plant or plant extracts referred to above, and those mixtures could be used in the present invention. The embodiments of the present invention employ a highly hydrogenated triglyceride (wax) where the iodine number closes to zero so that the thermally more stable compound becomes. Waxes can be chosen from those having an iodine number of from 0 to 30, but a wax having an iodine value ranging from 2 to 5 is preferred.

There are many different types of coating and ink formulations. Ink type selection depends on many factors including: i) Type of equipment used for coating or printing; ii) The need to reduce volatile emissions of ink or coating; and iii) The physical properties of the ink or coating required (including solubility, barrier properties, compatibility, color). The ink and coating formulations generally include a film-forming resin or polymer and a pigment or dye. Inks and coatings are routinely used to print and coat consumer packaged foods, for example only, but not limited to, items such as corrugated cardboard used for cartons; milk containers; paper containers; brown paper; cardboard for coated; paper and similar. The level of wax is generally incorporated in ink and adhesive coatings to make them more resistant to the usual wear and abrasion ranging from about 0.5% - 5% by weight of the formulation. In other embodiments, the wax may comprise about 1% to about 3% by weight of the formulation, and in other embodiments, the level of wax in the formulations of the present invention is in the range of about 1% to about 2% by weight. weight of the formulation. In one embodiment of the composition of the present invention, the ink or coating formulation used is water based due to the functionality or compatibility of the hydrogenated vegetable oil wax with other components of water-based coating and ink formulas. The embodiments of the present invention are particularly well suited for water-based flexographic inks which are widely used in the industry. The embodiments of the present invention could be used in other types of printing inks, provided that the waxes are compatible with other components of the formulation, and there is no swelling or degradation of the waxes in such formulations. An example of an ink formulation consists essentially of between 20% -60% (percent by weight) of an acrylic resin dispersion, between 5% -30% (percent by weight) of a pigment, between 0.5% -10%. % (percent by weight) of an alcohol, between 0.01% - 5% (percent by weight) of a defoaming agent, between 20% - 75% (percent by weight) of an aqueous solvent, and between 0.5% - 5% (percent by weight) of a vegetable wax, hydrogenated, the wax is characterized by an iodine value between 2 and 5. Concern for the environment, such as the increasingly rigorous regulation of air quality issues, Pollution and disposal of hazardous waste has created a need for alternatives to the use of petroleum, petroleum-based products, or other organic solvent-based ink compositions. Formulations of water and / or soy based inks are developed to reduce the amount of volatile organic compounds released into the air during printing. The embodiments of the present invention use a natural wax in ink and coating formulations with usual wear and abrasion. The waxes used include a palm oil wax, a soy wax, a castor oil wax, and a mixture of soy wax and castor wax, the waxes are prepared from hydrogenated oil. The mixture of castor oil wax and soy wax, in a ratio of 20%: 80%, is sold as Wax NAT 185 (Marcus Oil and Chemical, Houston, TX). These waxes can be used as food additives. The properties of soy wax are summarized in the Table 1, where it can be observed that this wax has IV of approximately 2. The IV of the palm wax (Table 2) is approximately 5.

AGL: Free Fat acids, ** IS: Flavor index *** number of carbon atoms: number of double bonds (for example, 18: 2 refers to linoleic acid: palmitic acid (16: 0), stearic acid ( 18: 0), oleic acid (18: 1), arachidic acid (20: 0) and behenic acid (22: 0) * number of carbon atoms: number of double bonds (for example, 18: 2 refers to linoleic acid) The wax of soybean oil has a melting point, as measured by Mettler Drip Point, of between 155-160 degrees F (67.65-70.4 ° C), while the wax of palm oil is between 136-142 degrees F (57.2-60.5 ° C). These waxes are further characterized by having a viscosity of between 10-200 cps at a temperature of 210 degrees F (97.9 ° C). Each wax comprises 98% triglyceride by weight with micro-quantities of fatty acids. The triglyceride can be saponified through the addition of a base such as KOH to produce a saponification index. Saponification rates will vary depending mainly on the chain length of the fatty acid which is a function of the source of the vegetable wax. For palm wax and hydrogenated soybean the saponification rate is usually in the range of 180-200 mg KOH / g. When the waxes were analyzed for their fatty acid content using known methods of Liquid Gas Chromatography ("CLG"), the soy wax (Table 1) was found to comprise between 82-94% stearic acid (C18: 0) and between 3-14% palmitic acid (C16: 0). In comparison, palm oil wax (Table 2) comprises approximately 55% stearic acid (C? ß: o) / 39.5% palmitic acid (C160o) / 1.1% myristic acid (Ci4o) and about 1.0% oleic acid (C? 8 :?). Castor wax, also referred to as hydrogenated castor oil, is catalytically hydrogenated castor oil (hydrogenation of castor oil in the presence of a nickel catalyst). Castor wax is a brittle, hard wax that is extremely insoluble in water and commonly used organic solvents, as is known to those skilled in the art. The wax has a melting point of about 183 degrees F to about 185 degrees F (about 84 degrees C to about 88 degrees C), and is characterized by having an acid number of 2-3 (mg KOH / g), a saponification number of about 174-186 (mg KOH / g), and an iodine number ranging from about 3 to about 4. Castor wax has been used in the preparation of coatings that are either water repellent , or resistant to oils, petroleum and petroleum products. While a primary use of castor wax is in the manufacture of fats, it is also used in paper coatings for food packaging and cosmetic applications, and castor wax derivatives are used as surfactants and plastics additives. There is a difference in the stearic acid content of these waxes, the palm and soy waxes having between about 84% to about 92% stearic acid, and about 1% stearic acid in castor wax. The properties of the mixed wax (NAT 185) are described in Table 3, this wax has a melting point of about 185 ° F (85 ° C) and an IY of 5 maximum. An ink composition generally includes four elements, a colorant, a vehicle, a solvent and additives. The colorant is used to provide the visible image on the substrate, and the colorant can be either a pigment or a dye, depending on the final use of the ink formulation. The vehicle serves to attach the dye to the substrate, and also serves as the carrier of the ink in the press. The solvent can be part of the vehicle; it serves to provide a means for drying, and is used to solubilize other components which provide flow properties to the vehicle, while the additives are used to impart a variety of special properties to the ink formulation. The dyes can be divided into either pigments or dyes, the dyes are characterized by being soluble in the ink vehicle or the solvent used in the ink. The dyes include black pigments, which are generally forms of carbon black, and white pigments, which can be either transparent or opaque. Opaque white pigments generally include either titanium dioxide (Ti02), zinc oxide (ZnO) or zinc sulfide (ZnS), titanium dioxide being the most commonly used. Alumina hydrate, magnesium carbonate, calcium carbonate, precipitated barium sulfate, talc or clay, and with or without one or more other agents used as extenders, are included within the transparent white pigments. The color pigments may be either inorganic or organic (ie, synthetic). Some examples of inorganic pigments include, but are not intended to be limited to, blue such as iron blue, Milori blue, Prussian blue, chromium (III) pigments, ultramarine pigments, iron cyanide blue, cadmium pigments , lead chromate pigments (which may not be recommended for use with food containers), luminescent, metallic effect and pearlescent pigments. Among the organic pigments that may be included, but not proposed to be an exhaustive list, are compounds such as azo compounds, benzimidalolones, yellow diaryluro, monoazo yellow salts, dinitraniline orange, pyrazolone orange, a variety of reds and browns azo, reds and browns of naphthol, and azo condensation pigments, such as lacquers, copper phthalocyanines, quinacridines, pyrrolopyrroles diaryl, dye pigments, aminoantoaquinone pigments, dioxazines, isoindolinones and isoindolines, and quinophthalones. One embodiment of an ink composition of the present invention includes a pigment. The pigment can be selected from the inorganic or organic pigments described above, from the synthetic dyes, or combinations of the pigments and / or dyes, is determined by factors such as the desired color of the final product, or the final use of the ink. One embodiment of the present invention employs a black pigment, and the black pigment is carbon black. The solvent may be selected from a variety of aqueous or non-aqueous solvents, such as, but not proposed to be limited to, water, alcohols such as ethanol, propanol, isopropanol, n-butyl alcohol, isobutyl alcohol or sec alcohol. -butyl; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone or cyclohexanone; esters such as methyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, n-butyl acetate, isobutyl acetate, or amyl acetate; ethers such as DOWANOL® PM (trademark of Dow Chemical Co., Midland, MI), methyl CELLOSOLVE® (trademark of Union Carbide Co.), CELLOSOLVE® or butyl CELLOSOLVE®; aliphatic compounds such as hexane; naphtha, octane or mineral or aromatic alcohols such as toluene or xylene. In a flexographic ink, the solvent may comprise up to 70% of the composition. Other types of solvents may be solvents derived from petroleum, such as an aliphatic petroleum fraction having a boiling point in a range of 435 ° -535 ° F (223.8-279.4 ° C), mainly used in lithography by thermofixation and typographic printing, at concentrations ranging from 35-45%, or 450-50%, respectively. Other petroleum fractions such as toluene, lactol alcohols, esters and ketones can be used in gravure printing formulations, and the solvent can comprise up to 85% of the ink composition. However, due to environmental considerations and regulations, the use of solvents which do not emit amounts of volatile organic compounds in the atmosphere is preferred. One embodiment of the present invention uses water as the solvent. In commercial production, these wax-containing inks may include the incorporation of additives, such as, but not limited to, surfactants, solvents and / or co-solvents, and / or other stabilizing agents and / or preservatives to increase life. Useful in deposit of ink formulations. Some of these additives may be included in the composition within the range of about 0.001% to about 7% by weight of the composition. These agents can be chosen from the group consisting of an anti-fogging agent, a biocide, an antifoam, a dispersing agent, an antioxidant, an ultraviolet ("UV") absorber, light stabilizers, a flow agent , a brightness improver, a pH regulator, a preservative, a rheology modifier (viscosity) and an anti-sedimentation agent. Examples of preservatives and biocides include sodium dehydroacetate, 2,2-dimethyl-6-acetoxysiloxane, ammonium thioglycolate, biocides such as DOWICILs® (Dow Chemical Co., Midland, MI), eg DOWICEL 75, 150 and 200, benzoate salts, sorbate salts and the like, in concentrations ranging from about 0.0001 to about 5% by weight.

Examples of agents that may be used to regulate ph include acids, bases, amine salts, carboxylate salts, phosphate salts, sulfite salts, amine salts, and others, present in concentrations ranging from about 0% to about 1% by weight. Examples of agents which may be used as rheology modifiers (viscosity) include polyvinyl alcohol; modified cellulose such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose; Water-soluble acrylic resins and polyvinylpyrrolidone. Examples of surface tension control agents are anionic and cationic surface active agents such as polyethylene glycol ether sulfate, ester salts and the like as anionic compounds; and polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene alkylamines and similar compounds, such as TWEEN.RTM. and TRITON.RTM. surfactants (Rohm and Haas Co., Philadelphia PA) as nonionic compounds. Sodium lauryl sulfate and related compounds may also be used. Surfactants of the IGEPAL® series (Rhodia, Inc., Cranbury, NJ) or TERGITOL® (Dow Chemical Co., Midland, I) may be used. Additionally, one or more humectants may be added. Examples of such humectants include polyols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, glycerol and polyethylene glycols or various molecular weight ranges. Depending on the end use, such humectants may comprise up to about 15% by weight of the composition. One embodiment of the present invention is based on an aqueous flexographic ink. The final use of the ink, such as for high speed newspaper printing, gravure inks, thermal offset, thermofixing, letterpress, screen printing, spraying, brush application, or the like, will determine which additive or additives, and concentrations of them, will be added to the final formulation. Although the present invention has been described with a certain degree of particularity, it will be understood that the following examples are only for the purpose of illustrating the embodiments of the present invention, the scope of the present invention is proposed to be defined by the claims. PREPARATION OF EXAMPLES Example 1. Properties of waxes. A commercially available mixture of hydrogenated soybean oil and hydrogenated castor oil known as STEROTEX® K (Abitec Performance Products, Columbus OH) was jet milled in a MICRON-MASTER® jet mill (Custom Processing Services, Reading PA) to a particle size of 10 microns. The material was easily micronized. This micronized material is commercially available as Marcus NAT-185 wax (Marcus Oil &Chemical, Houston, TX). NAT 185 wax is a mixture of hydrogenated castor oil wax (20%) and hydrogenated soy wax (80%). Another commercially available wax (S-368 N5T, from Shamrock Technologies) was used for comparative purposes with the wax composition of the present invention. The properties of these waxes are summarized in table 3. Table 3. Wax properties 1. Shamrock Technologies, Inc. Foot of Pacific Street, Arkansas, New Jersey 2. Hegman indicates the particle size based on the Hegman Scale, which is in accordance with ASTM-D 1210 (Test Method for Vehicle Systems Dispersion of Pigment by Caliber type Hegman). 3. Marcus Oil & Chemical, 14549 Minetta, Houston Texas Example 2. Ink Formulations To test the effectiveness of the wax composition of the present invention, the ink formulations of a water-based flexographic ink were prepared including a commercially used wax (Shamrock S- 368 N5T), the wax of the invention (NAT 185) and a control preparation that does not contain wax additives. Starting with a master batch of a commercial water-based black ink known to contain no wax, a small amount (100 gm) of water-based test inks (100 gm) was made. The composition of the black ink, a commercially used ink formulation, sold by Weber and Permut, Inc.

(Linden, NJ) is summarized below (Table 4).

Table 4. Black Ink Composition (Wax Free Master Lot) 48% Acrylic Resin Dispersion (RHOPLEX®, Rohm and Haas, Philadelphia, PA) 14% Carbon Black 1.0% Isopropyl Alcohol 0.5% Antifoam (SURFYNOL® MD-20, Air Products Corp.

Allentown, PA) 37% Water A black ink was chosen because it is known that black inks easily show differences in brightness, and rub resistance tests are generally easy to read. The pH of this ink was about 8.2 to about 8.6. The three different test inks are identified in Table 5. 1. Masterbatch free of black ink wax (composition described in table 4) 2. Shamrock Technologies, Inc. Foot of Pacific Street, Ne ark, New Jersey 3. Marcus Oil & Chemical, 14549 Minetta, Houston Texas The commercial wax chosen, Shamrock S-368 N5T, is known in the industry as a wax of fine particle agitation, and served as a control, while the ink formulation that does not contain slip and rub additives served as a "white "for these experiments. The inks were made by first dispersing the wax in an amount of ink by hand on a glass plate, then giving each ink a loose pass using a 3-roll laboratory mill (5 inches by 2.5 inches (12.7 cm by 6.35 cm ), not hydraulic) at room temperature. Care was taken not to heat the ink during processing.

The dispersed wax preparations were then added to the remaining amount of the ink using a laboratory mixer (Hamilton Beach Drinkmaster double sheet, operating at a PowerStat setting of 50) operating at moderate speed, to reduce foaming and prevent Inks are heated significantly. Each ink formulation was mixed for 10 minutes. It is recognized that for commercial production, these wax-containing inks could more likely involve the incorporation of other additives, such as, but not limited to, surfactants, co-solvents and / or other stabilizing agents and / or preservatives to increase the shelf life of formulations, ink. These additives are well known to those skilled in the art, but no attempts were made to prepare a long-term stable ink for the batches of ink formulation tested in these experiments. Example 3. Evaluations of Ink Formulations. The test ink formulations prepared in Example 2 were tested for properties such as slip, gloss, and rub resistance.

. Sliding is a measure of the resistance to movement between two objects, and is usually measured by placing two objects, one on top of the other on another surface, and raising the surface, like an inclined plane, until one object slides on the other object . The gloss is a function of the ingredients of the ink, the substrate, and the smoothness of the surface of the ink film. To test the brightness, a known amount of light is angled on the ink surface, and is collected after reflection of the ink surface. The percentage of light collected is directly related to what an observer sees as brightness. The rubbing is used to measure the resistance of the printed sample to scratches from the repeated rubbing of its surface. The tester generally rubs a sample of an abrasive or a sample of the unprinted raw material, against a sample of the raw material printed by a certain number of cycles and at a specific pressure. The results are judged by a visual observation of the sample. For each of these tests, a series of paint tests of the three test ink formulations were made on Leneta Book Test Sheets Coated Form 3NT-3 using a Mayer # 6 rod. The paint tests were oven-dried for 30 seconds at 140 ° F (59.9 ° C), and then allowed to stand at room temperature for 24 hours before the test. Property: BRIGHT Brightness readings were taken on dry prints using a Gardner Brightness Meter with the 60 ° aperture. Three readings were taken in one impression, the results were averaged and summarized in Table 6.

Table 6. Ink Formulation Brightness Readings Property: Roce The Sutherland Roce Test was also done using these ink formulations. The following observations were made in a visual examination of the test samples. Sample A, which does not contain wax, showed poor slip, but considerable resistance to rubbing. Sample B, which contains Shamrock wax S-368 N5T showed good slip, and considerable rub resistance, as did sample C, which contains the NAT-185 wax of the present invention, showed good slip, and considerable resistance to touch.

Although there was considerable rubbing of the ink in the test formulations containing either the S-368 waxes N5T or NAT-185, these formulations showed much less scratches from the dried ink film than did the sample containing no wax. Based on these data, the wax composition NAT-185 of the present invention improves the slippage of the ink formulations to virtually the same degree as the commercially used S-368 N5T wax. The friction resistance of S-368 N5T and NAT-185 waxes is comparable. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (27)

CLAIMS Having described the invention as above, the contents of the following claims are claimed as property:

1. Ink composition, characterized in that it consists essentially of: between 20% -60% (percent by weight) of an acrylic resin dispersion; between 5% - 30% (percent by weight) of a pigment; between 0.5% - 10% (percent by weight) of an alcohol; between 20% -75% (percent by weight) of an aqueous solvent; and between 0.5% to 5% (percent by weight) of a wax derived from hydrogenated vegetables, the wax is characterized by an iodine number between 2 to 5.

2. Ink composition according to claim 1, characterized in that the Wax comprises between 1% - 3% of the composition.

3. Ink composition according to claim 1, characterized in that the wax is further characterized by a melting point between 120 ° F (48.4 ° C) and 190 ° F (86.9 ° C) (Mettler drip point).

4. Composition according to claim 3, characterized in that the wax is further characterized by a. a melting point of approximately 185 degrees F (84.9 ° C) (Mettler drip point) b. a softening point of approximately 156 degrees F (68.8 ° C); and c. a Brookfield viscosity of about 10 cps at 100 degrees C.

5. Composition according to claim 3, characterized in that the wax is selected from the group consisting of castor wax, palm wax, and soy wax, or a mixture of castor wax and soy wax.

6. Ink composition according to claim 3, characterized in that the solvent comprises between 20% -50% of the composition.

7. Ink composition according to claim 6, characterized in that the solvent comprises between 30% -40% of the composition.

8. Ink composition according to claim 3, characterized in that it additionally comprises between 0.01% - 5% (percent by weight) of a defoaming agent.

9. Ink composition according to claim 8, characterized in that the pigment is selected from the group consisting of carbon black, an organic pigment, a synthetic pigment, or a combination thereof.

10. Ink composition according to claim 9, characterized in that the pigment is carbon black.

11. Ink composition according to claim 8, characterized in that it additionally comprises one or more agents selected from the group consisting of anti-fogging agents, biocides, dispersing agents, antioxidants, ultraviolet light absorbing agents, light stabilizing agents, - flow agents, gloss agents, humectants, pH regulators, preservatives, rheology modifying agents, surface tension control agents, and anti-sedimentation agents.

12. Ink composition according to claim 8, characterized in that the solvent is water.

13. Coating for a cellulosic product, characterized in that it comprises a mixture consisting essentially of: between 20% -60% (percent by weight) of an acrylic resin dispersion; between 5% - 30% (percent by weight) of a pigment; between 0.5% - 10% (percent by weight) of an alcohol; between 20% -75% (percent by weight) of an aqueous solvent; and between 0.5% to 5% (percent by weight) of a wax derived from hydrogenated vegetables, the wax is distinguished by an iodine value between 2 to 5, whereby the coating, when applied to the cellulosic product, makes the cellulose-coated product resistant to damage from usual wear and abrasion.

14. Coating according to claim 13, characterized in that the wax comprises between 1% -3% of the composition.

15. Coating according to claim 13, characterized in that the wax is selected from the group consisting of castor wax, palm wax, and soy wax, or a mixture of castor wax and soy wax.

16. Coating according to claim 14, characterized in that the wax is further characterized by a. a melting point of approximately 185 degrees F (84.9 ° C) (Mettler drip point) b. a softening point of approximately 156 degrees F (68.8 ° C); and c. a Brookfield viscosity of approximately 10 cps a 100 degrees C.

17. Coating according to claim 14, characterized in that it additionally comprises between 0.01% - 5% (percent by weight) of a defoaming agent.

18. Coating according to claim 17, characterized in that it additionally comprises one or more agents selected from the group consisting of anti-fogging agents, biocides, dispersing agents, antioxidants, ultraviolet light absorbing agents I, light stabilizing agents, agents of flow, brightness enhancers, humectants, pH regulators, preservatives, rheology modifying agents, surface tension control agents, and anti-sedimentation agents.

19. Method for reducing the usual wear and abrasion of a coated cellulosic article, the method characterized in that it comprises the steps of: preparing a mixture consisting essentially of: between 20% -60% (percent by weight) of a resin dispersion acrylic; between 5% - 30% (percent by weight) of a pigment; between 0.5% - 10% (percent by weight) of an alcohol; between 20% -75% (percent by weight) of an aqueous solvent; and between 0.5% to 5% (percent by weight) of a wax derived from hydrogenated vegetables, the wax is characterized by an iodine number between 2 to 5; applying the mixture to a surface of the cellulosic article; and allowing the applied mixture to dry, whereby the applied coating reduces the damage from usual wear and abrasion to the coated cellulosic product when the coated cellulosic product is subjected to one or more tests, the test is selected from the group consisting of rubbing , abrasion, slip and shine.

Method according to claim 19, characterized in that the mixture additionally comprises between 0.01% - 5% (percent by weight) of a defoaming agent.

21. Method according to claim 20, characterized in that the wax comprises between 1% -3% of the mixture.

22. Method according to claim 21, characterized in that the wax is further characterized by a melting point between 120 ° F (48.8 ° C) and 190 ° F (87.7 ° C) (Mettler drip point).

23. Method according to claim 22, characterized in that the wax is further characterized by a. a melting point of approximately 185 degrees F (84.9 ° C) (Mettler's drip point) b. a softening point of approximately 156 degrees F (68.8 ° C); and c.

24. A method according to claim 21, characterized in that the wax is selected from the group consisting of castor wax, palm wax, and soy wax, or a mixture of castor wax and soy wax.

25. Method according to claim 20, characterized in that the mixture additionally comprises one or more agents selected from the group consisting of anti-fogging agents, biocides, dispersing agents, antioxidants, ultraviolet light absorbing agents, light stabilizing agents, flow, brightness enhancers, humectants, pH regulators, preservatives, rheology modifiers, surface tension control agents, and anti-sedimentation agents.

26. An aqueous, flexographic ink composition characterized in that it consists essentially of: between 30% -50% (percent by weight) of an acrylic resin dispersion, the acrylic resin dispersion comprises between 25% -45% solids; between 10% -20% (percent by weight) of a pigment; between 0.5% - 2% (percent by weight) of an alcohol; between 0.1% - 1% (percent by weight) of a defoaming agent; between 30% - 40% of an aqueous solvent; and between 1% to 3% (percent by weight) of a wax derived from hydrogenated vegetables, the wax is distinguished by an iodine number between 2 to 5, the wax is selected from the group consisting of castor wax, wax palm, or a mixture of castor wax and soy wax.

27. Cellulosic article, characterized in that it is coated with a composition resistant to the usual wear and tear, the composition consists essentially of: between 20% - 60% (weight percent) of an acrylic resin dispersion; between 5% - 30% (percent by weight) of a pigment; between 0.5% - 10% (percent by weight) of an alcohol; between 0.1% - 1% (percent by weight) of a defoaming agent; between 20% - 75% of an aqueous solvent; and between 0.5% to 5% (percent by weight) of a wax derived from hydrogenated vegetables, the wax is distinguished by an iodine number between 2 to 5; the wax is selected from the group consisting of castor wax, palm wax, or a mixture of castor wax and soy wax; and wherein the cellulosic article is selected from the group consisting of corrugated cardboard, brown paper, coated paperboard, and paper.