JPS6213195B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a process in which a sensitized area, or a portion of a sensitized area, subsequently develops a color, i.e., becomes visible, by contacting a color-activating substance. - It relates to a technique for sensitizing a support containing a generating component. In particular, latent sensitizing inks are disclosed that can be applied to selected areas of a support by a variety of conventional printing methods.

``carbonless'' paper and uncolored,
Techniques for applying color-generating materials to supports are known. Previously, application of these uncolored or latent color-generating materials involved coating the entire surface of the support using water-based coating compositions and techniques. These techniques could not be applied to patterned areas where color-generating materials were selected. Therefore, in order to provide a support with the ability to image only a portion of the support, a portion of the support may be reduced by the application of a desensitizing compound as disclosed in U.S. Pat. No. 3,809,668. Other techniques have been developed to make it more sensitive.

As the technology for providing and developing latent images advances, particularly in the field of paper-based feedback systems for applications in the education sector, color-generating components can be conveniently applied to selected areas on a support such as paper. The demands to do so have become more intense. A steam and pressure transfer technique was used in which a latent coreactant was applied to selected areas of the paper sheet to provide a latent sensitization zone, which was applied to the area of the sheet containing the latent coreactant. The color is developed by the application of a second co-reactant from a source such as an applied wax crayon. These systems are exemplified by US Pat. Reproduction techniques are used to provide latent images for subsequent development and are exemplified in US Pat. Nos. 3,451,143 and 3,632,364.

U.S. Pat. No. 3,632,364 also discloses the application of hidden images by lithographic, mimeograph, letterpress, gravure, hand stamp, and screen printing techniques.
The disclosed method involves application of a special oxidizing compound capable of oxidizing iodide to iodine to selected areas of the sheet containing starch or polyvinyl alcohol. Subsequent application of an oxidizing iodide compound to the areas where the oxidizing compound has been applied to the support results in the formation of a visible image.

Although prior art steam and pressure transmission and spirit reproduction techniques have proven useful in providing small numbers of reproductions containing hidden images, conventional printing methods using ordinary paper A satisfactory method of providing a large quantity of such reproductions has been sought. The aforementioned US Pat. No. 3,632,364 requires a special iodide oxidation system with a prepared sheet containing starch or polyvinyl alcohol. U.S. Pat. No. 3,850,649 relates to the printing of latent coreactants capable of forming colored complexes with metals by lithographic offset printing techniques.
The co-reactant is a special 2 type suitable for lithographic offset printing.
Incorporated into the fast-curing ink carrier of the phase. US Pat. Nos. 3,540,909 to 3,540,914 also disclose "colorless" printing inks containing phenolic polymeric materials dissolved in petroleum solvents. After dot printing, the acidic polymeric material contacts the basic color forming material to form a visible image. US Pat. No. 4,063,754, issued December 20, 1977, discloses compositions and processes that provide solventless or "hot melt" imaging compositions.

The present invention is based on the total weight of the ink composition,
A non-polymeric, lipophilic, organic proton-donating acidic anion with a cationic counterion from about 5 to 55
A latent sensitized ink comprising, by weight, a binder component, up to about 30 weight percent thinner and up to about 70 weight percent particulate filler, and from 20 to 30 weight percent of a polymeric hydrocarbon thermoplastic terpene resin. overcame the incompetence of the prior art by providing The ink can also be used as one of the above ingredients or as an additional ingredient.
Contains at least about 5% by weight of at least one color-generating component. The proportion of filler-pending agent component is approx.
The ratio is 0.1:1 to 6:1. The polymeric hydrocarbon thermoplastic terpene resins useful in this invention are well known and commercially available under the trade name "Pitucolite" (Pennsylvania Industrial Chemical Company) and are polymers of pinene, particularly beta-pinene. It essentially consists of These polymeric terpene resins do not crack or "crack" when drying after application in the environment of the present invention.
The surface of the ink possesses the unique property of producing a color-forming co-reactant, whereby the surface of the ink remains open and receptive to the color-forming co-reactant. This effect is particularly surprising in view of the tendency of conventional polymeric ink extenders, such as varnishes, to form films that block the surface of the film and inhibit color-forming reactions. Thus, the addition of this unique polymeric component provides latent inks with improved imaging performance over latent inks without this component. It has been found that filler levels can be significantly reduced when using this polymeric component. Therefore, in some formulations, the ratio of filler to non-polymeric vehicle component is as a minimum about 0.1:1, and preferably about 0.1:1.
It has become possible today to reduce it to a level of 0.2:1. Other additional ingredients such as tack and viscosity modifiers, antioxidants, wetting agents, fluorescent brighteners and the like can be added as desired.

Proton donating acids refer to a class of proton donating compounds that donate protons to water molecules in an aqueous solution.

The term “color-generating component” used here means color-
Refers to any of the substances known in the carbonless paper art which become colored or produce the effect of visible coloration of a separate substance when in contact with an activating component. Therefore, the combination of substances is essential for color formation. For convenience, the ingredients in the latent sensitizing ink will be referred to herein as color-generating ingredients, whereas the ingredients used to subsequently develop the color will be referred to as color-activating ingredients, but the actual ingredients are described below. Can be substituted as described.

The vehicle components described above are desirably aliphatic, aromatic and cyclic carboxylic and sulfonic acids containing at least 6 carbon atoms and cation-containing salts of these acids. When used in the formulations of this invention, these vehicle components have sufficient lipophilic content to provide acceptable inkability and promote rapid, intense color development of the sensitized areas. They require a co-solvent reaction medium for rapid and intense color development of the sensitized area. It is particularly effective when accompanied by ingredients. Examples of these excipient components are rosin acid, stearic acid, oleic acid, 2-
Ethylhexanoic acid, 2-phenylbutyric acid, benzoic acid, hydrocinnamic acid and dinonylnaphthalenesulfonic acid and the corresponding cationic salts of these acids.

The vehicle components described are generally oily liquids or crystalline or amorphous waxy solids and, when dispersed or dissolved in thinners, have an inherent tackiness to the ink's suitability for application by customary printing methods. , exhibiting desirable bonding and viscosity modifying properties of conventional polymeric binders with respect to adhesion, and similar properties.

As noted above, the color-generating component may be one of the mentioned ink components or an additional separate component.
For example, the color-generating component may be the vehicle component or filler or both mentioned. Alternatively, the ink can include another transition metal salt as an additional, separate color-generating component.

In one embodiment, the vehicle component is at least 6
The color-generating developer component is a lipophilic organic proton-donating acidic anion containing 50 carbon atoms and having a transition metal ion. Transition metal counterions form colored complexes when contacted with color-activated metal complexing agents such as dithiooxamide (DTO) and its derivatives and polyhydric phenols.

The lipophilic anion moiety provides good ink adhesion and helps promote subsequent color development of the latent sensitized ink.

In this embodiment it acts as a vehicle component or a color-generating component. Because of this dual property of the vehicle component, these inks are capable of achieving the same color-generating component per unit area of support as is possible using a color-generating component incorporated in a customary polymeric film-forming vehicle. It is particularly useful for providing effective color-generating components of much greater density than the chromophores. These inks therefore develop color more quickly and more intensely than is possible by formulating inks with color-generating components in conventional ink vehicles such as conventional varnish-containing lithographic inks. Latent sensitizing areas can be provided that develop color upon contact with the activating component.

The transition metal counterions of these color-generating vehicle components are preferably selected from nickel, copper, iron and cobalt. Although nickel and iron are generally preferred, it is important to note that these metals are commonly colored metals such as DTO and its derivatives or polyvalent phenols.
This is because the activated co-reactant produces a black color. Representative color-generating vehicle components that can be used in the present invention are nickel, iron and copper derivatives of aliphatic, aromatic and cycloaliphatic carboxylic acids and sulfonic acids containing at least 6 carbon atoms and combinations thereof. It's a combination. Therefore, nickel rosinate, calcium nickel rosinate, nickel 2-ethylhexanoate, nickel stearate,
nickel 2-phenylbutyrate, nickel oleate, nickel benzoate, nickel hydrocinnamate, nickel dinonylnaphthalene sulfonate, and the corresponding copper and iron salts of the above compounds, and two or more of the above compounds. Mixtures are useful.

An essential component of the latent, sensitized ink of the present invention is a particulate filler, which can be dispersed in a liquid ink vehicle. These fillers are necessary to keep the sensitized areas conveniently receptive to the color-activating substances used to develop the latent ink. These fillers can be any of the customary pigments and extenders known in the printing art.
The filler can be selected to be nearly transparent when dispersed in the ink vehicle, or can be colored if desired. Thus, depending on the end use of the sensitized support when applied to a support, a latent unpigmented ink can be transparent to the point of view or very compatible with the support to which the ink is applied. Can have matching or contrasting colors.

Fillers must be selected with some care depending on the particular printing method to be used in the application. Therefore, for certain printing techniques, such as wet offset printing, hydrophobic fillers should be used to give superior results. Inks formulated in this way can also be used to aid in dry offset printing. A simple emulsification test can be used to determine whether a filler is suitably hydrophobic. This test involves grinding the pigment into the desired oil and mixing the resulting suspension with the desired aqueous offset reservoir solution. After the pigment-oil combination is briefly mixed with the ink fountain solution, the ink fountain solution is decanted and the remaining pigment-oil component is weighed. If the weight gain is greater than 20% by weight, the pigment is generally unsuitable for wet offset printing. For dry offset printing, Cab-O-
Relatively non-hydrophobic fillers such as colloidal silica sold under the tradename Sils (Cabot Corporation) can be used if desired.

The final particle size of the filler in the final ink composition should be less than about 10 micrometers and preferably less than 5 micrometers for easy application by conventional printing presses.

Typical fillers that can be used are pyrogenic silica, hydrated alumina, and trihydrate, powdered and pyrogenic anhydrous and particulate colloidal silica;
Commercially available “Eyarosil” and “Cab
-O-Sils" (available from Degutsu Sign Corporation and Kyabot Corporation, respectively), calcium and magnesium carbonates, barium sulfate, kaolin clay,
Attapulgite clay, bentonite clay, zeolite, zinc oxide, urea formaldehyde pigment,
and the like.

Fillers can comprise up to about 70% by weight of the ink composition. Higher amounts of filler may be needed on non-absorbent, smooth papers, but if the paper has a rough surface that absorbs the ink easily or the surface to which the ink is deposited is receptive to the co-reactant. Smaller amounts of filler can be used. In most applications, the filler is about 25% of the ink composition.
% by weight and most preferably from about 5 to 15% by weight of the composition.

It has been found that within the compositions disclosed above the ratio of filler to said expansile component is important. In order to obtain the desired printing characteristics along with excellent imaging speed and image density when the sensitized areas are contacted with the color-activating component, the proportion of filler to vehicle component should be approximately
0.1:1 to about 6:1 and preferably about 0.2:
It should be 1 or 1:1.

As previously mentioned, certain filler components have color-
Acts as a generating component. Acidified clays, e.g.
Kaolin, attapulgiaite and bentonite clays and natural and synthetic zeolites can be used to provide both color-generating and filler functions to the ink composition, since they are color-activated basic chromogens, i.e. This is because it possesses the ability to impart intense colors when in contact with leuco dyes, which are well known in carbonless paper technology. Generally, when these fillers are used as color-generating components, the weight percentage of fillers should be about 15 weight percent or greater to obtain satisfactory color development in the sensitized areas.

The thinners used in combination with the vehicle components in the inks of the invention described above are materials well known in the printing art. These substances are solvents, diluents,
and low viscosity oils that are added to the ink to reduce its consistency and tackiness, thereby modifying the rheological properties of the ink as required for use in particular printing processes. Typical thinner materials are liquid hydrocarbons, castor oil, dialkyl phthalates, trialkyl phosphates such as tributyl phosphate, alkyl carboxylates, low molecular weight alcohols, fatty alcohols, and the like. The amount and type of thinner used in any particular composition will vary primarily depending on the vehicle components and oil-accepting fillers used. Sufficient amount of thinner is added to the formulation to provide the proper viscosity and tack for the particular printing method used. Measurements of ink tack values commonly used in the art can be used to determine the appropriate amount of thinner to add. Generally, up to about 30% by weight thinner can be used. A desirable amount of thinner is about 10 to about 25% by weight of the total ink composition.

Although the use of the above-described vehicle components in combination with thinner in the present invention obviates the need for conventional varnishes to obtain satisfactory ink adhesion performance, the normal combination of vehicle and thinner Where tack, viscosity and other rheological properties are difficult to obtain, varnishes can be used in the formulation if it is desired to further modify these properties. Useful varnishes are phenolics,
Linseed oil, alkyds and modified alkyds, nitrocellulose, tung oil, cellulose acetate,
Drying oils and other naturally produced and synthetic polymers known in the art, such as ethylcellulose, and the like. It is possible to use up to about 40% by weight of varnish based on the weight of the total ink composition. It is desirable that the varnish constitute less than about 10% by weight of the ink composition, as the film-forming nature of these varnishes tends to inhibit the development of subsequent latent inks.

Agents that suppress the effect of oxygen on the components of the ink, ie, antioxidants, can be added to stabilize the ink components and the sensitized areas after color development. Useful antioxidants are well known in the printing ink art, and any known antioxidant that does not react with the color-generating components can be used. Color - When using antioxidants that react with the generating components, the ink may form undesirable "desensitized" or colored reaction products that may produce undesired colors in the sensitized areas. Dew.

Examples of antioxidants that can be used are thiourea, hydroquinone, hindered phenols such as alkylated hydroxytoluenes, and the like. Desirably, the antioxidant comprises no more than 10% by weight of the total ink composition, and most preferably no more than about 2.5% by weight.

To improve the application, performance and aesthetic qualities of the ink, if desired, other customary agents such as lubricants, fluorescent brighteners, dyes, waxes, buffers, wetting agents and flavoring agents and the like may be added. Ink additives can be added to the ink formulation. Generally these additives will make up about 2% or less of the ink composition and most preferably about 2% or less of the total ink composition.
Consists of 0.5% by weight or less.

If the filler is or includes one of the acidified clays or zeolites described above, the filler itself becomes the color-generating component instead of or in addition to the color-generating vehicle component. be able to. If both the extender and filler contain color-generating components, the latent sensitized ink will be colored by multiple separate color-activating components.

In addition to or in place of the color-generating components noted above, additional color-generating components or mixtures of color-generating components can be incorporated into the ink formulation.
Therefore, the ink formulation contains transition metal salts, such as transition metal nitrates, sulfates or halides;
It can contain DTO or DTO derivatives, polyhydric phenols or leuco dyes, all of which are color-
Development/color-known in the art as activating ingredients.

If more than one color-generating component is used in an ink formulation, care must be taken to prevent the components from prematurely reacting with each other. Therefore, transition metal salts and DTO derivatives will generally not be combined in the same formulation. Likewise, acidified clays and leuco dyes would not be combined. Typically, the ink will contain transition metal ions and acidified clays so that the ink can be colored by either or both DTO or other metal complexes or leuco dyes.

The ink can include ingredients such as varnishes to further modify the tack, viscosity and other rheological properties of the ink as previously described. Additional conventional ingredients such as antioxidants, lubricants, fluorescent brighteners, dyes, waxes, buffers, wetting agents, flavoring agents and the like can be added as required and generally The total composition in approx.
Contains 10% by weight or less. For example, ink is about 7
Up to % by weight of antioxidants may be required.
However, the amount is generally about 2.5% by weight or less, with the remaining additives ranging up to about 2% by weight and desirably less than about 0.5% by weight.

The preferred improved ink formulation is about 5 to 55
% by weight, and preferably from about 30 to 45% by weight of a non-polymeric, lipophilic organic acidic anion, such as nickel 2-ethylhexanoate, with a cationic counterion; 20 to 30% by weight; a polymeric, hydrocarbon thermoplastic terpene resin, such as a picucolite resin, about 5 to 15% by weight particulate filler, up to about 30% by weight thinner, and about 1
Contains % by weight of antioxidants.

The inks of the present invention can be made using conventional ink compounding equipment. Inks are generally prepared by combining all the ingredients and kneading to form a homogeneous mixture of suitable working consistency in an ink mixer. In some cases, the particulate filler is added in portions to the ink before it is milled. This blend is then passed through an ink mill, such as a three roll ink mill or other conventional ink mill, until a homogeneous viscous-viscous liquid is formed. The remaining filler is then added and the mixture is further kneaded to form a homogeneous dispersion. The particle size in the final mixture is about 10 micrometers or less to make it amenable to conventional printing methods. Other liquid components previously mentioned can be added to the compounded ink to adjust the tack, viscosity and other rheological properties of the ink as desired.

The inks of the present invention can be applied to selected areas of a support such as paper by conventional printing techniques including lithography, flexography, letterpress, dry offset, rubber plate intaglio, screen printing, gravure, and the like. It can be applied to These ink compositions are applied by conventional printing equipment to make them useful on patterned or dotted substrates, and in this way price or cost notices are applied only on certain sheets of multilayer sheet format. selectively increase paper or support for use in office forms where it is desired that the image appear only on certain portions of the form, such as invoices and purchase order forms, or on certain sheets of multilayer sheet forms. make you feel

The sensitized areas of the support can then be colored by contacting the sensitized areas or portions of the areas with a color-activating component. Typically, the color-activated component is contained in a paper sheet as an encapsulating component;
For example, included on CB (coated backing) sheets,
Thereby, when the CB sheet is placed in contact with the sensitizing sheet and written or typed on the front surface of the CB sheet, the capsules are destroyed and the color-
The activating component contacts the sensitized area or portion thereof containing the color-generating component and a visible image is formed.

Alternatively, the sensitized areas can be crayon- or color-
The sensitized area can be visibly colored by contacting with a coloring solution contained in the felt-tip pen containing an activating ingredient.

The multilayer sheet style office style includes one or more CB sheets superimposed and aligned with one or more sensitized CF (front coated) sheets. Thus, a multilayer sheet format will have a CB sheet as a top sheet overlying one or more aligned CB sheets that have at least a portion of their front surface sensitized. Writing or typing on the front surface of the top sheet causes similar information to be recorded on the sensitized portion of the front surface of the underlying sheet, with the underlying sheet being written or typed on the top sheet in a multi-layered sheet fashion. The information is consistent with the information provided.

In addition to latent sensitizing ink applied to the surface of the sheet, it is customary to sensitize or unsensitize areas of the sheet to provide forms for office entries, paper-based educational feedback systems, and the like. can be printed.

The following examples further illustrate the invention. In these examples, parts and percentages are by weight unless otherwise indicated.

Example 1 An ink was made for selected sensitized areas of paper with a latent co-reactant and had the following formulation: % by weight Nickel 2-ethylhexanoate 38.5 Hydrophobic silica filler (Eyalosil R-972) , Degutsusa, Inc.) 11.5 Polymeric terpene resin (Pitucolite S-135)
25.4 Butylated Hydroxytoluene (Antioxidant) 1.0 Hydrocarbon Oil (Maggi Oil #520) 23.6 Nickel 2-ethylhexanoate, terpene resin and antioxidant were dissolved in hydrocarbon oil. The filler was then dispersed into the solution and the final dispersion was milled on a three roll ink mill to a particle size of about 3 micrometers or less.

The ink was applied with a hand roller to selected areas of the sheet on 16 pound bond paper. After drying at room temperature, a sheet coated with the encapsulated dithiooxamide derivative (“3M” trademark carbon-free paper, type 200 CB [coated backing] sheet) was placed on the encapsulated coating and the surface to which the ink was deposited. were brought into contact with each other to develop color. The sheet was passed between steel pressure rolls to uniformly develop a color on 1.2 cm wide strips of the sensitized sheet. The colored area had a fair blue-purple color as measured by an optical densitometer.

The sensitized sheet was also developed by placing a sheet coated with the encapsulated dithioxamide derivative (CB sheet described above) so that the encapsulating coating and the ink-adhering surface were in close contact. An image was created on the sensitized sheet by writing with a ballpoint pen on the front surface of the CB sheet using normal hand pressure. Similarly, typing on the front surface of the CB sheet produced an image on the intensifying sheet. Image formation was extremely fast in both cases.

EXAMPLE 2 Selected areas of paper were sensitized with a latent co-reactant and an ink was prepared having the formulation shown in Example 1, particularly adapted for application by dry offset printing presses, with the exception that Airosil R-972 was used in the formulation. Non-hydrophobic silica filler (Cab-O-Sil M-
5) was replaced. This composition prints well on a dry offset press and develops well with the CB sheet in Example 1.

Claims (1)

Claims: 1. A pressure-releasable encapsulated color-activating compound, i.e., a color-generating component, which is provided on the support after being applied to the paper support by a printing press. In a latent printing ink for providing a latent sensitized area on a support, which can be developed with a compound capable of developing color, the ink contains about 5 ~55% by weight
a color-generating vehicle component, 20 to 30% by weight polymeric hydrocarbon thermoplastic terpene resin, up to about 70% by weight particulate filler, and up to about 30% by weight thinner; a vehicle component acts as a reaction medium for the reaction of said color-activating compound with said color-generating component and develops a color or forms a separate colored substance upon contact with said color-activating compound; with a transition metal inverse ion and at least 6
a salt with a lipophilic organic proton-donating acid anion containing carbon atoms, wherein the ratio of said filler to said color-generating vehicle component is from about 0.1:1 to 6:1. printing ink. 2 the anion of the color-generating vehicle component is aliphatic;
Latent printing ink according to claim 1, characterized in that it is selected from the group consisting of cycloaliphatic and aromatic carboxylic acid and sulfonic acid anions and mixtures thereof. 3. Latent printing ink according to claim 1, characterized in that the metal ions of the color-generating developer component are selected from the group consisting of nickel, copper, iron and cobalt. 4. Latent printing ink according to claim 1, characterized in that the filler consists of acidified clay. 5. The latent printing ink according to claim 1, wherein the thinner is a hydrocarbon oil.