FI59051B - TRYCKKAENSLIGT UPPTECKNINGSSYSTEM OMFATTANDE ETT KROMOGENT MATERIAL ETT MED DETTA REAKTIVT MATERIAL OCH ETT TERFENYLLOESNINGSMEDEL - Google Patents

Description

\ VJm £ 7] rB1 ANNOUNCEMENT _Qnc jSjft UTLAGG N I NQSSKRI FT 5 9051 C Patent filed 10 06 1931

Patent meddelat (51) Kv.ik.Vci-3 fi41li 5/12 FINLAND —FINLAND pi) P «iMtlWi« «ii-iK« i «waiailn | 3i + 5 / T3 (22) H «lwmtop« lvt —AnaMcnlngtdag 06.02.73 '' (23) AlkupUvi —Gittiftittsdig 06.02.73 (41) Tullut Julktetksl - Bllvlt offtntllg 08 73

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Patani ocn registerstyrelaen Anattkan utltfd och uti.skriftM pubitcmd 27.02.81 (32) (33) (31) Requested #o »oik« M — e * | ird priorityM n.02.72 USA (US) 225658 (71) Monsanto Company, 800 North Lindbergh Boulevard, St. Louis, Missouri, USA (72) James Kern Sears, Webster Groves, Missouri, USA

(7 * 0 Oy Kolster AB

(5 * +) The present invention relates to a pressure sensitive labeling system comprising a chromogenic material, a reactive material and a terphenyl solvent. reactive material and terphenyl solvent.

Conventional pressure-sensitive copy materials comprise a combination of a dye, i.e., a dye and a solid reactant, which are completely uniformly coated on a dye-bearing plate and a dye-receiving plate and are separated by a physical boundary fence which is eliminated by pressure. Such a copy material includes a first paper sheet material containing, as a completely continuous coating, capsules that break when pressed and containing a color with a chromogenic agent, i.e. a color-generating agent and a solvent, and a second paper sheet material with a solid acid-sensitive coating which reacts with the color to form a colored reaction product. There are enough capsules containing color, both in number and volume, so that a uniform pattern is created as the color comes out of the capsules when the image pattern is printed.

2 59051

The dye contained in the capsules of the first paper sheet may be a liquid mixture of varying composition, provided that it produces a colored mark upon contact with the solid reactant. The dye is usually required to be easily encapsulated using conventional methods, to retain it well when encapsulated, and to be resistant even to somewhat elevated temperatures. It is also important that the trace formed in the reaction between the dye and the solid reactant develops rapidly, withstands fading, does not leak and does not spread openly as a result of the capillary effect or other surface phenomena.

The dye is preferably a solution containing a solvent and a colorless or substantially colorless chromogenic material which generates a dye upon contact and reaction with a solid reactant, i.e. a sensitizing material. The advantage of such paints is that they do not stain hands, clothing, or other surfaces if they are accidentally broken over them.

Solid reactants, i.e. color sensitizers, contain finely divided acidic compounds which are also colorless or almost colorless in their natural form. Commonly used materials include organic polymers and inorganic clays, which are combined with a common binder used in paper coating, such as starch, casein, polymer, or latex, before being applied to the surface of the paper.

The purpose of the solvent is to be a carrier for the chromogen and a medium for the reaction between the chromogen and the acidic sensitizer. In common practice, the chromogen is dissolved in a solvent to form a solution that can be encapsulated and used as a coating on the second surface of the copy paper. The solvent must be able to keep the chromogen in solution inside the capsule and transport the color to the delicate paper when the capsule breaks, and the solvent must promote, or at least not inhibit, color development with the solid reactant. In addition, when the capsule may inadvertently break due to careless handling, the solvent must be a non-hazardous substance that does not harm the skin, clothing or the environment.

The performance of the imaging material is determined by how well the paper withstands heat and storage, how quickly and how strongly the color develops, and how durable the image is; the solvent also plays an important role in all these aspects. Little attention has been paid in the past to the role of solvents, instead focusing on improving chromogens and sensitizing materials and using only a limited number of compounds as solvents, such as crude oils and 3,590,51 distillates, toluene, perchlorethylene, xylene, chlorine-containing paraffin-nalactyl dioctyl dioctyl dioctyl dioctyl dioctyl. Chlorodiphenyls, alkyl diphenyls, and hydrogenated terphenyls have been proposed, for example, in U.S. Patent 2,646,367 as a substitute for crude oil in a system in which the crude oil acted as an inert, colorless dye carrier. Although some of these former applications have given fairly good results, only polychlorinated biphenyls have proven to be effective enough to produce dark and durable colors and only have commercial value as a color solvent, but so far it has not been possible to exploit the full potential of the color solvent to contribute. for the performance of imaging material * Some polychlorinated biphenyls have now been found to be biologically stable and potentially hazardous to the environment and therefore unsuitable for continuous use.

It is therefore an object of the present invention to provide solvents and solvent mixtures which are superior to those previously used in imitation materials and which actively participate in promoting paper performance. Other objects of the invention will become apparent from the following descriptions and examples.

The improved chromogenic material solvents used in pressure-sensitive imaging materials are terphenyls, partially hydrogenated terphenyls, terphenyls substituted with C 1-4 alkyls, and mixtures thereof having at least 65% estrogenic nature, and mixtures thereof containing organic. These solution mixtures result in a dark and non-fading color on resin or clay coated paper *

Pressure-sensitive copy paper systems using colorless dye solutions containing chromogens and the improved solvents of the present invention can be prepared according to well-known conventional methods. There are instructions in the literature for methods for making both color-bearing paper and color-receiving paper, either a resin-coated or clay-coated model, and these methods are not included in the present invention. In most cases, the solvents reported in this specification can simply be replaced by conventional color solvents, resulting in improved copy paper systems using prior art manufacturing methods.

The solvents of the present invention are preferably used in combination with one or more conventional chromogenic materials which are normally colorless, such a class of chromogens comprising colorless aromatic double-bonded organic compounds which change to a more polarized conjugate . A particularly popular class of chromogens comprises phthalide-type compounds such as crystal violet tylactone »which is 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, and malachite green lactone» which is 3-bis- (p-dimethylaminophenyl) phthalide. Other chromogenic substances which are phthalide derivatives are 3, 3-bi- (pm-di-propylaminophenyl) phthalide, 3,3-bis- (p-methylaninophenyl) phthalide, 3- (phenyl) -3- ( indol-3-yl) phthalides such as 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3,3-bis (phenylindol-3-yl) phthalides such as 3,3-bis (1,2-dimethylindol-3-yl) phthalide, 3- (phenyl) -3- (heterocyclic substituent) phthalides such as 3- (p-dimethylaminophenyl) -3- (1 -methylpyrr-2-yl) -6-dimethylaminophthalide, phthalides substituted with indole or carbazole such as 3 * 3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide and 3,3-bis ( 9-ethylcarbateol-3-yl) -5-dimethylaminophthalide, and substituted indole phthalides such as 3- (1,3-dimethylindol-3-yl) -3- (2-methylindol-3-yl) phthalide .

Other useful chromogenic dyes according to the invention are pyromellitides substituted with indole, such as, for example, 3 # 5-bis- (p-diethylaminophenyl) -3,5-bis- (1,2-phenyl) -3,7-bis- ( , (2-dimethyl-indol-3-yl) pyromellitide, 3, 5,7,7-tetrakis- (1,3-dimethylindol-3-yl) pyrimellitide and 3, 3 # 5 * 5- tetrakis (1,2-dimethylindol-3-yl) pyromellitidine and leucuramines and substituted leucuramines such as p-xylyl-leucuramine and phenyl-leucuramine. Similarly, orthohydroxybenzoacetophenone, 2,4-bis- [p- (p-dimethylaminophenylazo) anilino] -6-hydroxy-sym-triathine, N, 3 * 3-trimethylindolinobenzopyropyrans and H, 3,3-trimethylindolino -P-naftospiro-piraanit.

With the above-mentioned chromogens, an additional auxiliary dye can be used to prevent fading in cases where fading is a problem. Many phthalide compounds, such as crystal violet lactone, are characterized by rapid color development and a normal tendency to fade over time. One suitable additional colorant is benzoyl leukomethylene blue, which oxidizes upon contact with paper and forms a slow-lasting blue color. The combination of a phthalide dichromogen and such a colorless oxidizable additive results in a mixture that produces a color rapidly and does not fade.

The solvents of this invention are terphenyls, partially hydrogenated terphenyls and terphenyls having C 1-4 alkyls as aubet substituents having at least 65% aromatic character. Fully aromatic terphenyls are waxy solids with solidification points of about 55 ° C (o-terphenyl) to 213 ° C (p-terphenyl). Hydrogenation or alkylation of these compounds to reduce aromaticity lowers the pour point and the pour point of o-terphenyl is, for example, about -21 ° C when hydrogenated to a degree of aromaticity of 70. Partially hydrogenated terphenyls, especially those with an aromaticity of 65-85, are therefore generally more popular than fully aromatic terphenyls.

The solvents of this invention which are liquid at room temperature can be used either alone or in combination with diluents. Solvents that are solid or semi-solid at room temperature must necessarily be used in conjunction with another substance, hereinafter referred to as a diluent, to make the mixture liquid enough to be used in pressure-sensitive copy paper systems. For the purposes of this invention, the term "diluent" includes both inert and near-inert substances which are of little use alone as dye solvents because they dissolve chromogen only very poorly, or because they inhibit color development in some way, as do some more active materials. such as aromatic organic compounds which can be used alone as color solvents.

Both types of diluents can be used in conjunction with the solvents of this invention. For example, the solvent may be mixed with the diluent in a ratio of 0 to 3 parts of diluent per 1 part of solvent when the diluent is a mineral or vegetable oil such as fuel oil, paraffin oil, other hydrocarbon fractions, castor oil, hoof oil, whale oil, lard oil, olive oil, soybean oil, soybean oil coconut oil or turnip oil, or an organic aryl compound such as aromatic naphtha, C 1-4 alkylbenzene, benzylbiphenyl, or C 1-4 alkylarylindan. These thinners act by altering the physical properties of terphenyl, such as viscosity or vapor pressure, which may be advantageous due to handling or preparation. Thinners can also reduce the overall cost of the solvent used in the system, and in some cases, thinners can increase the effectiveness of the solvent, especially in that the color develops faster and the color lasts without fading.

Solvents may also contain some additives specifically designed to alter or control the final properties of the liquid, such as viscosity regulators, vapor pressure regulators, freezing point depressants, odor masking and antioxidant agents, colored colors, and the like.

6 59051

In a preferred embodiment of the present invention, the chromogenic material is dissolved in a selected solvent to form a dye that reacts with an acidic solid reactant. The acidic material can be any compound that meets the definition of a Lewis acid, i. electron acceptor with respect to the chromogen, and causes the chromogen to polarize to a colored form. The solid acidic material is also useful in that it adsorbs color when the image is reproduced. Commonly used acidic materials include acid clays and acidic organic polymerized materials such as phenol polymers, phenol-acetylene polymers, maleic acid-porosine resins, partially or completely hydrolyzed styrene-maleic acid-polymeric anhydride copolymers, and ethylene-maleic copolymer and fully or partially hydrolyzed vinyl methyl ether, maleic anhydride copolymer, and mixtures thereof.

The effect of different solutions on the rate and intensity of color development was determined by a laboratory study preparing a color containing a chromogenic solution in a test solvent, applying liquid to a receiving paper coated with a reactant of either clay or resin, and measuring the intensity and rate of color development.

In the following examples, a standard dye for resin-coated paper was prepared by adding 0.5 g of crystal violet lactone (CVL) to 10 g of solvent with stirring and heating to 100-120 ° C, if necessary to effect dissolution. The solution was cooled to room temperature, seeded with a few chromogenic crystals and allowed to stand for several days with stirring from time to time to ensure that the solution was not supersaturated. A standard dye for clay-coated paper was also prepared in the same manner by adding 1.15 8 of a mixture containing 5 parts of crystal violet lactone and 4 parts of benzoyl leukomethylene blue to 8.85 g of the chosen solvent.

Color development was tested by making a strip of color across a 1.25-inch (approximately 5 cm) wide strip of paper coated with either clay or resin using a drug dropper. The stopwatch was started and the line was applied to the surface of the paper tape with the help of a shaving blade. Five seconds after coating and at predetermined intervals thereafter, the paper reflectance was measured with a Fotovolt reflectometer. The meter was calibrated to record 100% reflection on special paper tested only when wetted as a solvent and backed by a white standard porcelain plate. Final reflection readings were taken on dry paper with a trace of the drawing, after 24 hours with a meter calibrated to record 7 59051 100% reflection on dry unstained paper. The degree of intensity of the developed color, denoted "color in percent," was calculated as 100 minus reflection; therefore, the higher the color percentage, the darker the developed color.

Table I shows the results of tests in which the corresponding solution mixtures have been evaluated, and shows the generally superior performance of the solvents of this invention. The specific materials shown in the table are for illustrative purposes only and do not limit the present invention.

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11 59051

Based on the information provided in Table I, partially hydrogenated terphenyls having an aromaticity of at least 65% are particularly suitable as solvents for chromogenic substances and useful in the preparation of pressure-sensitive copy materials. In particular, these compounds promote the rapid development of the color and the depth of the color, i.e. the darkness and the good retention of the color without fading, which is evident from the depth of the color even after seven days after the color has been exposed to light rays. Surprisingly, the compounds of this invention also overcome hydrogenated terphenyls, which have an aromaticity of only 60%. Although there is little difference in the performance of 63-75% aromatic terphenyls, a surprising decrease in performance occurs when the aromaticity is reduced from 65 to 60%.

In many cases, the partially hydrogenated terphenyls of this invention can be advantageously combined with a diluent or solvent, as noted in the examples in Table II. Such combinations are more advantageous because they can be used to optimize physical properties such as viscosity, melting point, or volatility, and thus to facilitate the use of a solvent in the manufacture of a pressure-sensitive copy material. In some cases, the addition of a diluent can improve the speed or efficiency of the dye solution, as shown by comparing Examples (f) and (g). Typical diluents were evaluated as the sole solvents used and the results can be seen in Examples (l) - (o) of Table II. · From these facts, it is clear that these diluents are of no practical use as the sole solvents and that the excellent results obtained with terphenyl and diluent combinations are mainly due to the presence of terphenyl.

Chlorobiphenyl, which contains about 42 l of chlorine, is a well-known commercial dye solvent which can be used alone or in combination with a diluent such as fuel oil. The efficacy of these agents is illustrated by the figures in Examples (p) and (q) in Table II. When comparing these figures with the results obtained from solvents containing the terphenyls of the present invention, it is found that in most cases the mixtures of this invention are as good or better in terms of their overall effectiveness than polychlorinated biphenyls.

Although the preferred embodiment of the present invention is a dual paper sheet system in which the receiving acidic material is supported by a second paper sheet and the chromogenic and solution-containing dye is supported by a second paper sheet, and the dye enters the acidic material when printed, the invention is not limited to such systems. The only requirement for pressure-sensitive copy systems is that the chromogen and acidic sensitizer be kept separate, i.e., not react with each other until pressure is applied to the system, and that the chronogen and acidic material come into contact and react with each other when pressed. Thus, it is possible to keep the chronogen and acidic material in a dry and unreacted state on a common substrate, and the solvent alone on a separate paper sheet, and by pressing to release the solvent into the mixture of chromogen and acidic material, causing local reaction and color development. Obviously, many other arrangements and solvent and impression material configurations and ratios with respect to their location in capsules on a substrate paper sheet or web are possible, and such arrangements are within the scope of the patent.

For example, it is possible to coat a single paper or backing on all components of this system and form a one-piece, self-contained unit that can be marked by moving the pen of a plotter or other means that presses against the surface of the paper. Papers such as these are particularly useful for use in inkless copiers.

The present invention thus encompasses pressure-sensitive copy paper systems which use, as the main reactants, a trace material, a chromogenic material, an acidic sensitizing material and a solution of terphenyl having an aromaticity of at least 6%. Those skilled in the art will recognize the various possibilities for variation and combination and will be able to take advantage of them when making pressure-sensitive copy paper systems from these reactive substances! these differences include, for example, the type of chromogenic material selected, the quality of the coating used and the manner in which it is applied, the number of excipients used, and the intended use of the system. The details set forth in the description and examples above therefore do not limit the present invention.

Claims (5)

15 59051 A pressure sensitive marking system comprising a paper web serving as a substrate. or sheet material, trace-forming components arranged side by side and supported on a sheet material, the components comprising a chromogenic material and an electron-accepting Lewis acid-type material capable of reacting with the chromogenic material to form a trace or label upon contact therewith; and for the chromogenic material, a liquid solvent released upon printing, characterized in that the solvent is terphenyl partially hydrogenated terphenyls, N-alkyl substituted terphenyls, or mixtures thereof having an aromaticity of at least about $ 65. System according to Claim 1, characterized in that the electron-accepting material, which is of the Lewis acid type, consists of acid clay or acidic organic polymers. A system according to claim 1, characterized in that the chromogenic material is dissolved in a liquid solvent before the chromogenic material and said electron-receiving material are brought into reaction with each other. A system according to claim 1, characterized in that the trace-forming components and the liquid solvent are present on a single substrate sheet. A system according to claim 1, characterized in that the chromogenic material is a phthalide compound.