US 3615750 A
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United States Patent Inventor Rush V. Blair 103 W. 4th St., Peoria, Ill. 61602 Appl. No. 46,833 Filed June 16, 1970 Continuation-impart of Ser. No. 873,502, Nov. 3, 1969, continuation-in-part of Ser. No. 718,914, April 4, 1968.
Patented Oct. 26, 1971 PLANOCRAPl-HC PRINTING INKS AND PROCESS FOR MAKING AND USING SAME 17 Claims, No Drawings US. Cl 106/27, 101/455 Int. Cl C09d 11/06 Field of Search 106/ 1 9-32;
Primary Examiner-Julius Frome Assistant Examiner-Joan B. Evans Attorney-Bacon and Thomas ABSTRACT: Planographic and lithographic printing inks comprising a substantially anhydrous polyhydric alcohol-in-oil emulsion are disclosed. These emulsoid inks may be used in planographic or lithographic printing processes and eliminate I the necessity of separate and repeated dampening of the plate between copies.
PLAN OGRAPIIIC PRINTING INKS AND PROCESS FOR MAKING AND USING SAME This application is a continuation-in-part of application Ser. No. 873,502 filed Nov. 3, 1969 which in turn is a continuation-in-part ofapplication Ser. No. 718,914 filed Apr. 4, 1968.
BACKGROUND OF THE INVENTION The present discovery relates to the printing art and, in particular, to the field pertaining to planographic or lithographic printing. This type printing has in recent years become one of the most widely used and, accordingly, much research has been devoted to this area in order to develop new and more efficient materials and processes. Lithographic printing generally entails the use of a planographic printing surface or plate which has areas possessing a distinct selectively to various substances.
Basically the planographic or lithographic plate is prepared by producing on the surface thereof ink receptive and water receptive areas, the latter being ink repellent areas. When the plate is contacted with an aqueous liquid, the aqueous liquid is absorbed to the water receptive areas and then when the ink is applied the ink is selectively absorbed by the ink receptive surface of the plate and accordingly rejected by the ink repellent areas. In the case of indirect of offset lithography the plate, bearing the ink in only those selective areas, is contacted with the printing blanket. The image by means of the ink is transferred to the blanket which in turn transfers the image to the sheet of paper or surface upon which the image is desired. However, in the case of direct lithography, the ink bearing plate is contacted directly with the sheet of paper or surface.
The various processes presently in use for preparing printing plates range from lithographic processes, where a design is made on the surface of the material by applying a greasy, water-repellent, ink receptive material such as crayon or lithographic chalk, to photographic processes where light sensitive bi-chromated gums or light sensitive diazo materials are exposed to an image pattern and the exposed materials are treated to obtain ink receptive areas. Any of these plates may be used with the printing ink of this invention.
In situations where many copies are to be made from the original lithographic plate, flexible plates are wrapped around cylinders and an aqueous solution and ink from separate fountains are supplied by rollers. In a typical printing operation, the cylinder bearing the lithographic plate having ink receptive and ink repellent areas, is first contacted with a roller wetted by a water or other suitable aqueous solution. The aqueous solution is absorbed by the hydrophilic surfaces but repelled by the ink receptive surfaces. The plate is then contacted with a roller wetted with an oil ink and the ink is absorbed by the ink receptive surfaces and rejected in turn by the ink repellent surfaces which are rendered oil repellent by the initial treatment with the aqueous solution. The plate is then contacted with the printing blanket to which the ink is transferred, and the blanket, in turn, contacts the sheet of paper upon which the design is to be printed. The ink is transferred from the blanket to the sheet and the entire process is repeated to obtain the individual sheets bearing the design This process requires the sequential application of water and ink each time a print is made, and this repeated operation decreases the useful life of the plate. Troubles are also encountered through partial comingling or emulsification of the oil and water on the plate.
One of the proposed methods for overcoming some of the defects of the described process has been the use of water-inoil emulsion inks. However, the emulsion inks heretofor suggested for use possessed drawbacks which have not made their use particularly feasible. Some of the inks previously proposed did not have the capacity to remain in an emulsive state, that is, these inks have a tendency to demulsify or break in the ink fountain or even during storage. Others do not provide sutisfnctory prints, particularly where a great number of copics are to be produced. In order to be effective for the purpose, the inclusion of the aqueous dispersed phase in the oily printing ink must not change significantly those physical.
characteristics of the ink which are requisiteto the satisfactory fulfillment of its'function as a printing means. When an ink emulsion demulsifies in the ink fountain ordoes not properly separate or break upon application to the printing surface, the printed image is dull, less intense, and spotted or stippled. The nonimage area is sometimes toned or discolored.
BRIEF DESCRIPTION OF INVENTION The present invention is directed to polyhydric alcohol-inoil emulsion inks, their preparation and use, and in particular to substantially anhydrous emulsion inks which ((I) possess the requisite balance of stability for storage and use; ((2) permit the obtention of repeated numbers of printed images which do not possess the attendant disadvantages of the prior art water-in-oil emulsion inks; and ((3) eliminate the necessity of dampening the lithoplate previous to each application of the emulsion ink during successive printings.
GENERAL DESCRIPTION OF THE INVENTION The emulsion inks of the present invention consist essentially of an external or continuous phase of an oil having dispersed therein ink pigments and a nonpigmented internal or discontinuous phase of at least one relatively low molecular weight polyhydric alcohol, which is immiscible in the oil, preferably a mixture of trihydroxy and dihdroxy alcohols such as glycerine and ethylene glycol, preferably containing one or more surfactants which possess the solubilities and surface activities to (a) promote the preferential wetting of the nonimage areas of a conventional lithoplate by the polyhydric alcohol, (b) where necessary, maintain the emulsive relationship between the respective phases in the ink fountain while permitting the necessary separation of the phases on the plate, and (c) act as a lubricant between the phases. In general, a surfactant system suitable for purposes of the invention will have a hydrophile-lipophile balance value in the range of from about 12 to 30 but the surfactants must additionally be selected to provide for the preferential wetting of the nonimage areas of the lithoplate with the polyhydric alcohol, where necessary, to maintain the desired stability of the em ulsion, and desirably to provide lubrication between the phases.
The inks are prepared by mixing the polyhydric alcohol or alcohols containing the selected surfactant or surfactants with the oily ink dispersion until a substantially homogeneous emulsion is obtained. The use of oil-wettable pigments insures that the pigment remains in the external oil phase and does not transfer to the nonpigmented internal polyhydric alcohol phase. The resulting emulsion is allowed to age for a short period of time and then remixed. The use of the emulsion inks of the present invention in lithographic processes eliminates the need for repeated dampening of the lithoplates as a separate step during the printing operation. The polyhydric alcohols preferentially seek out and wet the nonimage areas of the plate and repel the oily ink phase. Water is not necessary and may be eliminated entirely.
The oil phase of the emulsion is composed of a suitably oily ink vehicle, including those oils and varnishes which are generally used in printing inks, having dispersed therein a printing ink pigment. The word oil as used herein is intended to include all such vehicles. A wide range of printing ink vehicles are known to the art, including hydrocarbonaceous oils such as mineral oil, seal oil, and the like which usually contain predominantly aliphatic components but which may also contain some aromatics, drying oils such as linseed oil, tung oil, other unsaturated oils of either natural or synthetic origin, and mixtures thereof, and varnishes containing either natural or synthetic resins in suitable oily solvent systems. Any of these known vehicles containing pigment dispersed therein may be used as the oily ink phase of the polyhydric alcohol-in-oil emulsion of the invention. While the invention is not limited thereto, varnishes containing long flow isophthalic alkyd resins, chlorinated rubber resins or cyclized rubber resins in the proper solvents, as known to the trade, provide very satisfactory vehicles which with added pigment comprise the oil phase of the present composition.
The isophthalic alkyd resins which may be used in the oil phase function not only as an oil but also act to bind the drying oil or varnish pigment dispersion to the surface to which the image is transferred. The use of chlorinated rubber and cyclized rubber resin oils have proved to be very advantageous since these oils permit the obtention of more stable and more uniform emulsions. The selection of surfactant becomes more flexible when the cyclized rubber oils are used since the emulsion may be sufficiently stable without dependence upon added surfactant. However, the invention in its broad aspects is not limited to these oils.
Carbon black is the commonly used pigment but it has been found that various colored inorganic pigments such as the metal oxides, for example, iron oxide, can be used depending, of course, upon the color desired. Organic pigments such as benzidine yellow, benzidine orange, phthalocyanine blue, phthalocyanine green and Sherman Williams Brilliant Toning Red B can also be used. in fact, any colored pigment which is preferentially wet by the oil phase can be used and will function both as an emulsifier and coloring agent. in addition, the oil phase may contain minor amounts of known additives, such as, agents which prevent formation of skin upon exposure of the oil phase to air, agents such as stearic acid which improve the ability of the oil phase to cover the ink receptive area of the printing plate, etc. These additional ingredients and their respective functions are well known to the artisan and can be varied or even eliminated as the situation demands. The oil phase may constitute from about 50 to 85 percent by weight of the total emulsion weight and preferably constitutes from about 58 to 84 percent by weight.
The internal phase is composed primarily of the polyhydric alcohol or mixture of trihydroxy and dihydroxy alcohols, in which the surfactant or mixture of sulfactants has been dissolved or dispersed, where necessary. The alcohols which have been found to yield particularly good quality inks are glycerine and ethylene glycol, but other polyhydric alcohols containing from 2 to 5 carbon atoms and having generally the same properties may be used. Representative of such other alcohols are 1,3 -butanediol, l,4-butanediol, 1,5-pentane diol and 2.2'-oxydiethanol. This phase constitutes from about to 50 percent, and preferably from about 16 to 42 percent, by weight of the total weight of the emulsion. These percentages include the content of the surfactant or surfactants which when required usually represents from about 0.2 percent to about 3 percent by weight of the total emulsion weight or more specifically represents from about 3 to 6.8 percent by weight of the total weight of the internal phase. No water is necessary or desirable in the composition although a small amount of water, such as may be included with surfactant solutions, or absorbed from the atmosphere may be tolerated. in general, the amount of water, if present at all, is less than about 5%. The expression substantially anhydrous as used herein does not exclude such minor amounts of water.
The surfactant or surfactants of the system may be those which possess a hydrophile-lipophile balance (referred to as HLB) which is capable (a) of maintaining the polyhydric alcohol-in-oil emulsive relationship, (b) of providing the necessary lubrication between the two phases, and (c) of permitting the preferential wetting of the nonimage areas of a lithoplate with the polyhydric alcohol, three properties which are imperative if an emulsion ink is to perform as necessary. The HLB of an emulsifier is an expression of its hydrophile-lipophile balance, i.e., the balance of the size and strength of the hydrophilic (water-loving or polar) groups and the lipophilic (oil-loving or nonpolar groups of the emulsifier.
A single surfactant may act in all three capacities, or satisfactory results can be obtained by choosing different surfactants tailored to meet the three objectives above, Le, a multicomponent system with one component serving to lower the surface tension of the polyhydric alcohol, another serving to stabilize the alcohol-in-oil emulsion and still another to serve as a lubricant. in certain instances, the oily phase containing the dispersed pigment may be of such nature that a sufficiently stable emulsion with the polyhydric alcohol is formed without the necessity of incorporating a surfactant in the polyhydric alcohol phase to serve the emulsion stabilizing function. in this instance it is only necessary that a surfactant be selected which is soluble in the polyhydric alcohol phase and which will lower its surface tension and/or serve as a lubricant. Those skilled in the art, guided by the present disclosure, will know how to select surfactants to accomplish the objectives stated. See, for example, the publication of the Atlas Chemical Industries, Inc. entitled The Atlas HLB System copyright 1963. The surfactant system of the invention must be at least partially soluble in the polyhydric alcohol, cause the alcohol to preferentially wet the nonimage areas of the plate, cause lubrication between the phases and, if necessary, at the same time keep the alcohol emulsified in the oil while the ink is in the fountain.
it is known both theoretically and experimentally, barring other offsetting influences, that the lower surface tension liquids wet metal or other high surface-energy solids more easily. The surface tension values for all liquids are temperature dependent. At room temperature most of the lower molecular weight glycols exceed 35 dynes/cm and those for the organic oils (the basic ink components) are less than 35 dynes/cm. Hence on the absence of any surfactant or other offsetting condition the oil-carbon black dispersion will compete successfully for the image and nonimage areas of the lithographic plate alike. However, in the presence of a glycolsoluble surfactant that lowers the glycol surface tension to a value slightly below that of the oil-carbon black phase, it will be the glycol that wets the nonimage area and not the oil-carbon black dispersion. It is further observed that if the glycol surface tension is lowered excessively it will begin to wet even the naturally glycol-repellent image area. An offsetting condition in this invention which aids the nonimage area being preferentially wet by the internal phase is that initially the nonimage area is wet by polyhydric alcohol solution with a sponge, cotton pad or cloth. Hence for the oily ink phase to subsequently wet the nonimage area, the absorbed layer of polyhydric alcohol must first be removed. But because this polyhydric alcohol layer is continually being replenished via the internal phase during the printing operation and because the polyhydric alcohol phase is bound strongly to the nonimage area, it is difficult if not impossible for the oily ink phase to gain access to the nonimage area. Hence some formulations do not require the addition of wetting agents.
The experimental effects of surfactants acting as emulsifiers are well known. As noted above, the reason for the emulsification of the glycol and oil-carbon black dispersion is to permit the transfer in ink from the ink fountain to the inking rollers and then to the lithographic plate. Where combinations of surfactants for wetting, lubrication and emulsification are employed, any emulsifier that does not interfere with the wetting and lubricating surfactant is permissible.
If the oil phase and the polyhydric alcohol phase are mixed in the presence of a suitably surfactant system when required to accomplish the above, the ink emulsion obtained is not only stable in the ink fountain, but upon use in a lithographic process permits the preferential wetting and provides for good ink distribution on the ink rollers. in addition an adequate number of impressions per plate with each impression exhibiting good intensity and definition and, in general, a fine quality can be obtained. These impressions can be made without the necessity of dampening the lithoplate after each printing and before the application of the ink.
In using the present emulsion inks the plate may be preliminarily contacted before the first printing with a liquid which will preferentially wet the nonimage areas and attract the internal phase of the ink. This liquid need not contain water, although aqueous solutions, such as aqueous glycerine solutions, can be used at this stage. A suitable pro-dampening liquid is a polyhydric alcohol containing an agent which will lower its surface tension, such as, for example, a liquid indentical to the internal phase of the ink emulsion. Glycerineethylene glycol solutions which have been acidified, eg with oxalic acid are also quite suitable. The plate is contacted with the pretreating solution before the first printing only since the subsequent dampenings are accomplished by the polyhydric alcohols of the ink itself.
Representative surfactants which may be included in the surfactant system are (a) the monoand di-glycerides of fatty acids such as steric, palmitic, oleic, lauric acids and mixtures thereof; (b) polyoxyalkylene fatty acid polyol esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene propylene glycol monostearate, polyoxyethylene glycol monolaurate, polyoxyethylene glycol mono-oleate, polyoxyethylene glycol monostearate, polyoxyethylene glyceryl stearate, polyoxyethylene sorbitan monopalmitate, polyoxethylene sorbitan monolaurate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan mono-oleate, which are soluble in the polyhydric alcohol phase; and (c) surfactants of the morpholinium quaternary ammonium salt type and represented by N-soya-N-ethyl morpholinium ethosulfate, and N-cetyl-N-ethyl morpholinium ethosulfate. Types (a) and (b) are representative of nonionic surfactants which may be blended together or with other nonionic or cationic surfactants having a higher HLB value. The type (a) surfactants have a relatively low HLB value and perform the function of stabilizing the polyhydric alcohol-in-oil emulsion. The type (b) nonionic surfactants are more strongly hydrophilic than type (a), in general are soluble in the polyhydric alcohols and lower their surface tension and promote their wetting of the printing plate. Other surfactants which will perform this function as well as providing lubrication between the phases, and which can be used along where emulsion stability is not a problem, include certain organo-silicones having combined hydrophobic and hydrophilic action in the same molecule, such as those wherein the molecule contains a silicone portion providing low surface tension and hydrophobic characteristics and a polyoxyalkylene portion providing hydrophilic action and compatibility with other materials. Such products are described in a Technical Service Bulletin of the Research and Development Department of the Union Carbide Corporation entitled Union Carbide L-75, L-76, L-77, L-78 and L-79 (nonionic types), Organo-Silicone Surfactants. Members of type (a) and (b) can be selected in suitable proportions to provide an HLB in the range of about 12 to 30. The cationics of type (c), in general, have an HLB in the upper portion of the recited range and possess the necessary wetting and emulsifying properties to be used alone in the emulsion inks of the invention. They can also be used to raise the HLB value of the nonionics (a) and/or (b) to provide a surfactant system capable of performing the triple function required. It will be understood that the invention is not limited to the use of these recited surfactants but can employ any surfactant system capable of performing the necessary functions in the polyhydric alcohol-in-oil emulsions.
The amount of surfactant or surfactants added to the emulsion and more specifically, to the polyhydric alcohols depends upon the surfactants selected and the HLB value of the surfactant system as well as on the composition and the relative percentages in the emulsion of the respective phases. The amount of surfactants used can only be generally defined in terms of function, i.e., that which is necessary at the selected HLB within the stated range to (i) maintain the emulsive relationship between the two phases, where necessary, (ii) to accomplish the preferential wetting ofthe image and nonimage areas of a lithoplate, and (III) to provide lubrication between the phases.
The process of producing the subject polyhydric alcohol-inoil emulsion ink comprises the steps of initially mixing the alcohols with the surfactant or surfactants. Optionally, a pH control agent may be included to ensure that the ink remains substantially neutral or slightly on the acid side. A small amount of potassium bitartrate or equivalent buffer is suitable for this purpose. After an intimate mixture, or more specifically, a solution or dispersion has been obtained, the oil medium composed of an ink pigment dispersed in an oil generally used for the purpose, is admixed with the polyhydric alcohol solution. The medium is then mixed for a period of time until an emulsion or a completely homogeneous mixture of droplets of the polyhydric alcohol solution dispersed in the external or oil phase is obtained. The emulsion is then allowed to stand at the ambient conditions for a period of time ranging from a few hours to 24 hours and then remixed to ensure that a complete dispersion is attained. The emulsion can be used after cooling; however, it is preferable to allow the emulsion to age for a period of a few days and as long as 30 days. The aging period permits the emulsion to attain a state of thermal equilibrium which in turn enhances the stability characteristics of the emulsion.
As earlier stated, the emulsion inks of the present application contain various ingredients each of which serves a distinct purpose. The pigment oil phase serves to ink the ink receptive surface of the lithographic plate while the poly-hydric alcohol phase serves to dampen or wet the hydrophilic or water receptive areas in order to insure that these areas do not for one reason or another accept the ink.
The polyhydric alcohol-in-oil ink emulsion of the invention can be used quite effectively with any of the Iitho-graphic direct or offset printing processes which employ conventional printing plates having ink receptive and ink repellent areas. In a representative embodiment, the plate (e.g. a paper direct, photo plate or metal lithographic plate prepared in the usual manner) is installed in a printing apparatus which is conventional in design with the exception that a separate water fountain and plate dampening mechanism for the conventional and sequential dampening of the plate is not necessary. The plate is initially dampened with the pretreating solution which is attractive to the internal phase of the ink as by means of a cloth or sponge and a film of the polyhydric alcohol-in-oil emulsion ink in accordance with the invention is then applied to the dampened plate generally by means of the conventional ink roller. The milling action of the roller in contact with the plate facilitates de-emulsification and separation of the phases of the ink to permit their distribution to the plate areas individually attractive to them. The plate is then contacted with the surface to which the image is to be transferred or to a printing blanket. Where the image is transferred to a blanket the image is then in turn transferred to the surface of the material upon which the image is desired. The process is repeated with the exception that the plate is not dampened be fore each subsequent application of ink.
The present polyhydric alcohol-in-oil emulsions can be used to produce multicolored impressions merely by changing the pigment color and reprinting upon the same sheets upon which the initial colored impression was made.
DETAILED DESCRIPTION OF THE INVENTION The invention, having thus been generally described, will now be described in detail. However, the detailed descriptions are not to be construed as limiting but rather, are to be considered for illustrative purposes only.
Example 1 To one-half a fluid ounce of a mixture of 2 parts glycerine (7.46 g.) and 3 parts ethylene glycol (9.84 g.) was added one gram of Cream of Tartar (Potassium bitartrate), 0.1 gram of Ottasept (a fungicide which contains as active ingredients pchloro-m-xylenol and 4-chloro-2, 6-xylenol and which is available from Ottawa Chemical Company) and one gram ofa surfactant system having an HLB of 16.5 produced by blending the following:
percent Atlas G-IBOO-Polyoxyethylene glyceride ester having an HLB of 18.1, and
10 percent Atlas Arlacel No. 186-A mixture of monoand di-glycerides of fat forming fatty acids having an HLB of 2.8 and containing a few hundredths of a percent of preservatives.
These materials were thoroughly mixed until a uniform solution was obtained. The polyhydric alcohol base solution thus obtained was added with mixing to 50 grams oil based carbon black ink having the following composition:
4 l .75 grams of carbon black pigment l98.45 grams ofchinawood gel (tung oil) I 13.40 grams of a long flow isophthalic alkyl resin 3.0 grams of hydroquinone (an anti-skin agent) The medium was mixed thoroughly until a completely homogeneous emulsion of the droplets of the polyhydric alcohol phase (internal) dispersed in the oil phase (external) was obtained.
The emulsion was then allowed to stand at ambient conditions for a period of 24 hours to allow settling of any undispersed materials and to allow the emulsion to reach thermal equilibrium since there is a redistribution of heat during mixing. After this, the emulsion was again mixed thoroughly. After the final mix, the emulsion was allowed to age for about 7 days at ambient conditions in a closed container during which substantially complete thermal equilibrium is reached.
Example 2 Example 1 was repeated with the exception that 1 gram of a surface active agent, Atlas No. 263, a 35 percent aqueous solution of N-cetyl-N-ethyl morpholinium ethosulfate having an HLB of about 30 was substituted for the surfactant i.e. the mixture of 90 percent Atlas G-l300 and the 10 percent Atlas Arlacel No. 186.
Example 3 Example 2 was repeated with the exception that only onequarter of an ounce of the mixture of glycerine and ethylene glycol was used and a cationic surfactant, Atlas G-272, a 35 percent aqueous solution of N-soya-N-ethyl morpholinium ethosulfate, having an HLB of from about 25 to 30 was used in place of the aqueous solution of N-cetyl-N-ethyl morpholinium ethosulfate used in that example.
Example 4 Example 3 was repeated with the exception that one-half of a fluid ounce of the glycerine, ethylene glycol solution was used.
Example 5 Example 4 was repeated with the exception that 1.5 grams of the 35 percent aqueous solution of N-soya-N-ethyl morpholinium ethosulfate (HLB=25-30) was used.
Example 6 To 1 fluid ounce ofa mixture of 2 parts glycerine (14.92 g.) and 3 parts ethylene glycol (l9.68 g.) was added 1 gram of Cream of Tartar (potassium bitartrate), 0.l gram of Ottasept (a fungicide which contains as active ingredients p-chloro-mxylenol and 4-chloro-2. 6-xylenol and which is available from Ottawa Chemical Company) and l gram of a cationic surfactant Atlas G-272 a 35 percent aqueous solution of N-soya-N- ethyl morpholinium ethosulfate, having an HLB of from about 25 to 30.
The resulting admixture was thoroughly mixed until a uniform solution was obtained. The solution thus obtained was added with mixing to l00 grams of chlorinated Latex resin varnish based carbon black ink having the following composition:
150 grams of Pope & Gray Latex varnish No. VZ236l (chlorinated rubber latex in appropriate hydrocarbon oil solvent) 45 grams carbon black The medium was mixed thoroughly until a completely homogeneous emulsion of the droplets of the polyhydric alcoholphase (internal) dispersed in the oil phase (external) was obtained.
The emulsion was then allowed to stand at ambient conditions for a period of 24 hours to allow settling of any undispersed materials and to allow the emulsion to reach thermal equilibrium. After this, the emulsion was again mixed thoroughly. After the final mix, the emulsion was allowed to age for about 7 days at ambient conditions in a closed container during which substantially complete thermal equilibrium is reached.
Example 7 Example 1 was repeated with the exception that the pigmented oil contained iron oxide (red-pigment) as the pigment in place of the carbon black.
Example 8 To 1% ounces ofa mixture of 2 parts glycerine (7.46 g.) and 3 parts ethylene glycol (9.84 g.) was added 2 grams of Cream of Tartar, 0.1 g. Ottasept and 2 grams of the surfactant Atlas G-27l which is a 35 percent aqueous solution of N-soya-N- ethyl morpholinium ethosulfate having an HLB of 25 to 30. The resulting materials were thoroughly mixed until a uniform solution was obtained. The resulting polyhydric alcohol base solution was added with mixing until thoroughly mixed with grams of an oil-based black ink to which 1 gram of magnesium silicate had been added and mixed. The oil-based black ink had the following composition:
1 13.45 g. carbon black pigment l l3.45 g. water resistant gloss 226.90 g. long flow isophthalic alkyd resin 3.00 g. hydroquinone The medium was mixed thoroughly until a completely homogeneous emulsion was obtained. The emulsion was then allowed to remain at room conditions in a closed container for approximately 24 hours. After this period the emulsion was again thoroughly mixed and then allowed to age for 7 days. After this period the emulsion was examined and found to be stabilized and ready for use.
Example 9 By procedure similar to that of Example 8 an emulsion ink was prepared from the following:
External phase 100 grams as follows:
75 percent LBX 296-b 25 Varnish (a heavy print varnish containing approximately 73 percent cyclized rubber dissolved in a paraffinic hydrocarbon solvent having a boiling range of 620-675 F.)
25 percent carbon black Internal phase 2 fluid ozs. as follows:
2 parts glycerine 3 parts ethylene glycol 2 grams Atlas G-27l Surfactant 2 grams Atlas G-263 Surfactant 6 grams Cream of Tartar 6 grams gum tragacanth Example l0 An emulsion ink was prepared according to the following formula:
a. 100 grams external phase containing 30 percent by weight of carbon black milled into 70 percent by weight of a varnish prepared by dissolving 42 percent by weight ofa petrol soluble cyclized rubber resin having a melting range of l40 C. (capillary method) in 58 percent by weight of a solvent mixture of aliphatic petroleum oil solvents having boiling ranges within 450 to 700 F. of the type used in the preparation of heat set printing inks to which 2.4 percent by weight, based on the weight of the solvents, of stearic acid had been added;
b. 2 fluid ounces internal phase consisting of 2 parts by weight of glycerine and 3 parts by weight of ethylene glycol to which 2 grams of a nonionic organo-silicone surfactant (L76 Silicone, Union Carbide) for reducing surface tension and for lubrication between the phases had been added.
The components (a) and (b) were thoroughly mixed and allowed to set for approximately 7 days before use. The emulsion was used in lithographic printing as herein described with excellent results.
Example 1 l A silicated aluminum plate coated with a diazo material (as for example described in US. Pat. No. 2,714,066) was exposed through an image pattern and treated in a conventional manner to produce a reproduction of the image defined by ink receptive and ink-repellent (water receptive) areas.
The lithographic plate thereby produced was installed in a conventional lithographic printing apparatus with the water fountain and dampening rollers removed therefrom. The lithoplate was then dampened with aqueous glycerine solution and the dampened plate was then contacted with glycol-in-oil emulsion ink as produced according to example 1. The ink portion of the ink emulsion was attracted to and covered the ink receptive areas while the polyhydric alcohol phase of the ink emulsion covered the water receptive or ink-repellent areas. The inked plate was then contacted with a printing blanket to which the ink was transferred and the printing blanket was then contacted with a sheet of paper so as to transfer the ink image to the paper. The process was repeated with the exception that the initial dampening step was eliminated and the plate yielded impressions possessing excellent intensity and definition and, in general, good quality. The subsequently obtained impressions made without a separate dampening step were as good in quality as the first impression made after the first and only dampening step of the process. Accordingly, it was evident that the respective phases performed as required.
Example 12 The process of example 1 l was repeated. However, in order to increase the polyhydric alcohol receptive nature of the ink repellent portions of the lithographic plate, the plate was initially treated with an aqueous solution containing a small amount of glycerine and cationic surfactant Atlas 6-27 1. The printing process was then carried out as described in the foregoing example and again impressions of excellent intensity and definition were obtained.
Example 13 The process of example 1] was repeated using in place of the glycol-in-oil ink emulsion of example l the emulsion as described in example 4. More than an acceptable number of impressions were made which exhibited good intensity and excellent definition. The plate upon inspection did not show any signs of deterioration and additional fine quality prints could have been made.
Example l4 The process of example 1 l was repeated using the ink emulsions of each of the examples 1-10 except that the initial dampening solution was a substantially anhydrous mixture of glycerine and ethylene glycol which had been acidified with oxalic acid. Excellent results were obtained.
Example 15 The process of example ll was repeated until a sufficient number of copies were made. The lithoplate was then removed from the printing apparatus and a second plate bearing an image or design which was to be printed on the sheets or copies bearing the initial impressions. The red colored polyhydric alcohol-in-ink emulsion as described in example 7 was then substituted for the black ink emulsion and the copies were replaced in the appropriate place in the printing apparatus.
The process was carried out as described in example 1 l and prints were obtained which possessed separate black and red images or designs.
Example 16 An emulsion ink was prepared, as in example 10, from the following:
Examples 17-20 Emulsion inks are prepared from the same formulation as in Example 16 except that in lieu of carbon black the pigments are:
Example t7-benzidine orange Example l8-phthalocyanine blue Example l9phthalocyanine green Example 20-William's Brilliant Toning Red [3 Examples 21-26 Emulsion inks were prepared from the same formulation as in example 16 except that the polyhydric alcohol content of the internal phase was as follows:
Parts by wt.
Example 2 l-rt. Propylene glycol 20 b. Ethylene glycol 40 Example 22-a. LJ-Butanediol 24 b. Ethylene glycol 36 Example 23-3. l.4-Butanediol 24 b. Ethylene glycol 36 Example 26-a. l.5-pentanediol 24 b. Ethylene glycol 36 Example Z5-a. 2,2'-0xydiethanol 40 b. Ethylene glycol 20 Example 26a. N-Butanol 24 b. Ethylene glycol Each of the inks of examples 16-26 are suitable for the purposes of the present invention. To show the importance of using polyhydric alcohols of two to five carbon atoms further ink samples were made up using the same formulation as in example l6 except that one of the polyhydric alcohols of the internal phase contained more than five carbon atoms. The
TABLE No. of
Test Internal Phase Carbons No. Mixture in Mol. Results l 2 Parts Ethylene Glycol 2 satisfactory I Part Propylene Glycol 3 2 3 Parts Ethylene Glycol 2 satisfactory 2 Parts l,3-Butanediol 4 3 3 Parts Ethylene Glycol 2 good 2 Parts l,4-Butanediol 4 4 3 Parts Ethylene Glycol 2 satisfactory 2 Parts, LS-Pentanediol 5 5 3 Parts Ethylene Glycol 2 poor 2 Parts 2,5-Hexanediol 6 6 3 Parts Ethylene Glycol 2 satisfactory 2 Parts 2,2-Oxydiethanol 4 7 3 Parts Ethylene Glycol 2 poor 2 Parts N-Hexanol 6 8 3 Parts Ethylene Glycol 2 poor 2 Parts 2-Methyl-2,4-
Pentanediol 6 9 3 Parts Glycerol 3 poor 2 Parts 2-Methyl-Z,4-
Pentanediol 6 It is clear from the foregoing that various obvious modifications can be made to the invention described without deviating therefrom and it is fully intended that these modifications be within the scope of the invention as defined by the appended claims.
l. A polyhydric alcohol-in-oil ink emulsion for lithographic or planographic printing containing less than 5% water, consisting essentially of:
a. from about 50 to 85 percent by weight of an oily ink external phase comprising an oil-wettable ink pigment dispersed in an oily ink vehicle selected from the group consisting of mineral oils, fatty oils, synthetic drying oils, varnishes containing resins in an organic solvent, and mixtures thereof; and
b. from about to 50 percent by weight ofa substantially anhydrous, nonpigmented, internal phase consisting essentially of polyhydric alcohol and having surface tension properties which facilitate the preferential wetting of the nonimage area of a printing plate by said internal phase when the emulsion ink is applied to the plate, the polyhydric alcohol consisting of at least two polyhydric alcohols having from two to five carbon atoms.
2. An emulsion as defined in claim 1 wherein the polyhydric alcohol consists of a mixture of at least one dihydroxy alcohol of two to five carbon atoms and glycerine.
3. The emulsion of claim 2 wherein the mixture comprises ethylene glycol and gylcerine.
4. An ink emulsion as defined in claim 1 wherein the external phase constitutes about 58 to 84 percent by weight of the total emulsion ofglycerine and ethylene glycol.
5. An ink emulsion as defined in claim 1 wherein the polyhydric alcohol internal phase contains from about 3 to 6.8 percent by weight based on the weight of said internal phase at least one surfactant having an HLB of from about 12 to which lowers the surface tension of the polyhydric alcohol, said surfactant being selected from the group consisting of:
. monoand di-glycerides of fatty acids polyoxyalkylene fatty acid polyol esters morpholinium quaternary ammonium salts organo-silicones, and
. mixtures thereof.
An emulsion as defined in claim 5 wherein the surfactant comprises a mixture of a surfactant (a) with a surfactant (b) or (c) having a higher HLB value than (a).
7. An emulsion according to claim 5 wherein the surfactant material comprises a morpholinium quaternary ammonium salt.
8. An emulsion as defined in claim 7 wherein the morpholinium quaternary ammonium salt is selected from the group consisting of N-cetylN-ethyl-morpholinium ethosulfate and N-soya-N- ethyl-morpholinium ethosulfate.
9. An emulsion as defined in claim 5 wherein said mixture of surfactants is composed of a glyceride of a fatty acid and a polyoxyethylene fatty acid polyol ester.
10. An emulsion as defined in claim 1 wherein the pigment of the external phase is carbon black and the vehicle of the external phase is selected from the group of ink oils consisting essentially of synthetic oils, varnishes, linseed oil, tung oil and mixtures thereof.
11. An emulsion as defined in claim 1 wherein the ink vehicle is a printing ink varnish comprising a cyclized rubber resin dissolved in a hydrocarbon oil solvent.
12. An emulsion as defined in claim 1 wherein the ink vehicle is a printing ink varnish containing a chlorinated rubber resm.
13. An emulsion as defined in claim 10 wherein the internal phase contains a surfactant comprising a glyceride of a fatty acid and a polyoxyethylene fatty acid polyol ester.
14. A polyhydric alcohol-in-oil printing ink emulsion for lithographic or planographic printing containing less than 5 percent water, consisting essentially of:
a. from about 50 to percent by weight of an external phase comprising an ink pigment dispersed in a printing ink varnish containing a cyclized rubber resin dissolved in a hydrocarbon oil solvent; and
b. from about 15 to 50 percent by weight of a substantially anhydrous, nonpigmented internal phase consisting essentially of a mixture of glycerine and ethylene glycol containing at least one surfactant in an amount sufficient to lower the surface tension of the mixture of alcohols so as to promote preferential wetting of the nonimage areas of the printing plate when the emulsion ink is applied to the plate and serve as a lubricant between the internal and external phases of the emulsion.
15. The emulsion of claim 14 wherein the surfactant of the internal phase is an organo-silicone.
16. The emulsion of claim 15 wherein the external phase includes a low-molecular weight natural fossil hydrocarbon resin.
17. A process oflithographic printing which comprises:
a. contacting a lithographic printing plate possessing an image defined by ink receptive and ink-repellent areas with an emulsion containing less than 5 percent water and consisting essentially of about 50 to 85 percent by weight of an oily ink external phase comprising an oil-wettable ink pigment dispersed in an oily ink vehicle selected from the group consisting of mineral oils, fatty oils, synthetic drying oils, varnishes containing resins in an organic solvent, and mixtures thereof and from about 15 to 50 percent by weight of a substantially anhydrous, nonpigmented, internal phase consisting essentially of polyhydric alcohol and having surface tension properties which facilitate the preferential wetting of the ink repellent areas, the polyhydric alcohol consisting of at least one polyhydric alcohol having from two to five carbon atoms, to thereby apply ink to the ink receptive, image areas and polyhydric alcohol to the ink-repellent, nonimage areas,
b. transferring the inked image from the plate to an ink receptive material, and
c. repeating the inking and printing steps of (a) and (b) without intermediate application of dampening solution to the printing plate.
, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,615,750 Dated October 26, 1971 Inventor(s) RUSH V. BLAIR It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:
IN THE SPECIFICATION:
Column 1, lines 23, 24-, and 49, "absorbed" should read adsorbed-.
Column 1, line 26, "of" second occurrence should be --or-.
Column 3, line 71, a closed paren should be inserted after the word "groups".
Column 4, line 29, "on" should be in; line 43, "absorbed" should read -adsorbed-; line 55, after "transfer" the word "in" should be -of-; line 61, "suitably" should be -suitable Column 10, line 53, "Examples 21-26" should read -Examples 2l25-; lines 67 and 68, delete the following:
"Example 26a.N-Butanol 24 b.Ethylene glycol 36"; line 70, "16-26" should read -l625-.
Column 11, line 2, "6 and 8" should read and 6--; line 3, "26" should be changed to -25.
IN THE CLAIMS Claim 17, column 12, line 63, "one" should be changed to --twc and "alcohol" should be -alcohols--.
EDWARD M.FLETGHER,JR. ROBERT GO'I'TSCHALK Attesting Officer Commissioner of Patents USCOMM-DC GOSTG-PGD n us, sovzmmzm PRINTING orncznu onl-n0