US1740061A - Harold v - Google Patents

Description

Dec- 17, 1929 M. c. BEI-:BE ET A1. 1,740,061

I.|ITIIO(`IRAPI'IIC PLATE AND PROCESS 0F PREPARATION Original Filed Jan. 22, 1925 MURRAY iQ/Basinger cnnsnmn, ooNNEcTIcUT;

Raymann A.

THOMAS, .,KENTUGKY; Nn

HAROLD v. anamnesi-or Your swam, or Nonwoon, rome.. as.

sIGNons'ro-'T'Hnwanswonmz WATCH cass co.,'or. DAYTON, Intrigen-mln c'on- @iPoBATroN or, KENTUCKY y f LITnoqmHIo PLATE AND Pnocnss or rnnrmamrom original appli@mmf am; rainer-y 2a,

Y This inventionrel'ates particularly to plates for use in lithograpy kand to a process of preparing suchvplates.v

The primary'o'bject is to -provide plates of the-charactermentioned with printmg portions, suchl as rimages,-Vdesigns, characters, or

the like, whichare highly resistant to the disf integrating action of; lithographic ink, which will, nevertheless, -hold the ink satisfactorily, and which are also strong and durable and capable of withstanding the mechanical stress to vvhich, the lates are subjected in press-printing 'operatlons Y Still another important object is t0 provide an improved process for applying to plates, suitable for lithographingpurposes,l

f highly resistantk images, designs, or characters, which are capable of taking and holding the ink satisfactorily, and which will withstand the disintegrating action'of ink and possess such other resistant qualities as to enable these printing surfaces to be used successfully for producing a very large number of reproductions.

Accordingto the improved process, as preferably practiced, a lacquer comprising a Well thinned solution yof a highly insoluble and strongly resistant synthetic resinous compound is applied to those areas of a plate which are to serve as a medium for receiving and holding the lithographing ink and printing upon the surface to which the inkis to be transferred. It is preferred to employ a resinous compound which is insoluble in solvents of the order of-acetone, benzol (benzene, i. e., the coi-*tar product known as benzene), or the like; t'o diss/olve such highly insoluble resinous compound in a special solvent, as

. for example, furfural, and to mix the solution with suit-able thinners and preferably with certain other ingredients, thus producing a highly thinned lacquer. This lacquer then is applied in a thin coating to the sensitive areas of the plate at which areas the resinous compound and certain other ingredients in the coating are caused to become set and strongly adherent to the plate, while the solvent and thinning agents may be largely, or wholly, evaporated therefrom. Those portions of the plate which are not to permanent- 1s25,.s..r1a1 No. 4,103. Divided and um applic'dajtameaoctober l 20,1928. sum1 no. .s1a,9as. l

ly retain the image, design, characters which function in have applied thereto a suita le-)protective the printin proeessmay coating, such as a coating of gum. arabic,v rso that the selected areas only'vvill 'bepermanently coated with the resistantfcoating.

It is preferred to employ inthe-'lacquer a resin which is itself light-sensitive, or which has been rendered light-sensitive by @the incorporation ltherein of suitable' `sensitizing agents. If desired, acceleratt'jrs mayfbeemployed which comprise halogen-liberating agents. Also, Y synthetic resin which is rendered highly insoluble in character before it is dissolved in the special solvent, and which can' be rendered still more resistant and 'insoluble after the lacquer has been applied'` tothe fplate. Also, it is preferred to employ in the lacquer ahighly insoluble resin whlch can lbe still further hardened and rendered more insoluble by subjecting the plateto aheating operation after the lacquer has beenapphed.

As an example. one may takev a zinc plate and provide it with sensitive areas adapted to permanently receive the coating'substance which forms the image, design, or printing characters, may protect lthe remaining portions of the plate by a suitable coating,'such as asolution of gum arabic, may then coat the plate with the improved lacquer, Ina-y then harden the coating by heating the plate, and may then Wash the coating from the protected areas by a suitable developing operation. For example, this may be done by Washing with Water; or, the plate may be put to use in the press, Where the water from the damping roller, which ordinarily precedes the inking roller, will disintegrate the coating throughout the protected areas and leave the strongly attached portions of the coating, forming the image, or the like, in condition to receive and transfer the-ink in the printing operation.

The zinc plate may be provided with design areas. by applying-transfer ink, in the form of-an image, design, or characters, to the plate in a well-known manner; then coating the plate with gum arabic which adheres to those portions ofthe plate not covered by it` is preferred .to employ a' the transfer ink, and then washing olf the transfer ink, leaving the'clean underlying portions of .the zinc surface as "sensitive areas i. e. clean, bare areas. The improved lacquer may then be applied to the plate, may be hardened so that the exposed areas of the plate receive a permanent coating, and the 1ntervening protective coating may be removed by a developing operation (waslnng wlth water, for example), and the plate is then ready for use. It is to be understood that While the lacquer coating may cover the coating of gum arabic during the period when the plate 1s being subjected to heat to further harden the resinous coating, nevertheless, the gum arabic prevents .the resinous coating from becoming (strongly) adherent to the plate, and the coating, comprising the resinous compound and the gum arabic, may be readily washed oli' the plate, leaving the resistant resinous coating at those areas which are to be used to receive and transfer the ink in the rinting operation.

T e preferred method of preparing a suit-4 able lacquer in -accordance with the invention is, as follows:

First, repare a furfural-acetone resin by mixing ve hundred seventy-five grams of furfural and five hundred seventy-live grams acetone; pouring the mixture slowly into a saturated aqueous solution of sodium hydrate, say one thousand grams of such a strong, caustic solution, thus producing a resinous material; draining oil the caustic; crushing the remaining resin and washing it with a dilute solution of hydrochloric acid, say ten percent solution, to free it from the caustic; then heating the resin fora suitableV period, say two hours, in an open kettle, at about 300 C. The resin melts and ygradually thickens, while giving olf fumes.v The resin shouldbe constantly stirred during the heat.- ing period, and, at the end of the heating period, fumes are nolonger given off.

The heat treatment preferably is continued to a point where smallsamples of the resin are shown to be insoluble in benzol (benzene), and do not even discolor this solr Ent. The resin is then cooled and' crushed.

The lacquer preferably is formed by using the highly insoluble resin prepared in the manner described by dissolving the resin in a special solvent,si1ch as furfural, and compounding in accordance with the following formula:

Furfural-acetone resin, 400 grams; furfural 1500 cc.; benzene, 100 cc.; amyl acetate, or

ethyl acetate, 1200 cc.; celluloid, 6 grams; oil of cassia 10 cc.; oil of lavender 10 cc. i

The benzene and the acetate serve as thinners, or diluents. The essential oils disguise the odor of urfural and also resinify with heat: andthe Celluloid improves the inkholding uality of the coating and tends to toughen t e iilm.

p longer soluble in furfural.

The preferredmanner of compounding the materials is to dissolve 400 grams of the highly insoluble furfural-aceton resin, pre ared as described above, in about 1400 cc; o furfural, by heating to the boiling point for about twenty minutes; to add 500 cc. of an acetate (such as amyl or ethyl) while the solution is warm ;toy dissolve six grams of celluloid in 100 cc. cold furfural and add same to the solution; then mix 500 cc. of an acetate, such as ethyl acetate and 1000 cc. of benzene and add to said solution; and finally add the essential oils, i. e., oil of lavender and oil of cassia.

After the transfer ink has been washed oil, the sensitive areas, or image, on the gummed plate, the lacquer, prepared asv described,`is wiped over the entire plate with a rag and rubbed down into ya thin, smooth coating. For best results, the plate is then heated at about 100 C. for about one-half hour. This renders the resinous material even more insoluble. The plates may be sent directly to the press when cooled, in which case the Water from the damping roller of the press, coupled with the operation of the press, Willdisintegrate and remove the coating between the y areas which have received the permanent coating. If prefer-red, however, the coating appliedlover the gum varabic coating may be removed by washing with water before sending the plates to the press yIn any case, the lithographing ink will adhere only to the image in the printing operation.

The improved lacquer, prepared as. de'- scribed, possesses high penetrating qualities. The improved coating is of such chemical insolubility in inks, and its resistance to me-l chanical abrasion on the press in such as to render the product' far superior to a plate having simply an albumin coating, or a coating of other materials, such as have previously been used, including asphaltum. In fact, the improved lacquer provides an image far superior to that afforded by such coatings as albumin, asphaltum, or the like, even though the plate is not subjected to the heating operation after the lacquer has been applied threto. On the other hand, when the plate is subjected to the heating operation, the resin in the lacquer, which previously remained potentially reactive in some degree, is transformed into its ultimate insoluble and resistant condition, in which condition it is no.

While it is preferred -to employ furfural as a solvent for the furfural-aceton resin, any special solvent which will dissolve the resin in the highly insoluble condition maybe employed. Ani'line, or nitro-benzene will act as solvents, for example. However, such, solvents possess objectionable properties, having bad odors and being of poisonous character. .In any event, the solvent should be such that the dissolved resin can be wiped over the sensitivem area 'of theplate, and afforda thin, smoothcoatingg'also, the solvent should be such asto. dryat a reasonably rapid rslte after the film of lacquer has been ape n Y l P What has been referred to as transferring ink is the colored, greasy com ound which is applied to a photo transfer p ate and which adheres to the resistant-coating applied to sensitive areas protected .originally by transfer ink,.an ink image having been transferred to the plate and removed, afterI first coveringvthe intervening spacesY with gum.

Such an ink contains an oil, or'a grease. It.

may be readily washed v`olf the picture by means of alcohol benzine, erY turpentine.

Synthetic resins which are highly insoluble in oils, inks, orfthe solvents ordinarily used in lithographicprocesses are preferable.

The mannerl inwhich the process is racticed is illustrated-in the accompanying dli'awing2 in whichl y ig.' 1 is an elevational viewof a plan having ink characters, or designs, Vrinted thereon, illustratingthe first step o the process; Fig. 2 illustrates the condition of the plate after the application of the protective coa-ting to the areas not covered by the ink; Fig. 3 shows the condition after the ink has been removed Fig. 4 illustrates the condition after the lacquer has been applied; and Fig. 5 illustrates the condition after the lacquer has been finally hardened and the protective coating removed.

In the illustration in the drawings, A designates a plate, such as a zinc plate; and B, B designate the printing characters, or printing areas, formed on the plate in accordance with the improved process.'- The plate first has applied to its surface at the areas designated 1 the ink characters, or designs, 2. The areas of the plate not covered by the ink are designated 3. After the application of t-he ink, as by a transfer method, a protective coating, such as gum arabic, designated B, is applied to the areas 3. The ink is then wasked from the plate, leaving the areas' l bare and in proper condition to receive t-he lacquer. The lacquer, designated 4, is then applied in any suitable Way, as, for example, by rubbing a thin coating of the lacquer over the entire surface of the plate. The lacquer lills the spaces between .the areas covered by the protective coat-ing, and a thin film of the lacquer may also cover the protective coating.v

The plate is then subjected to heat treatment which has the eliect of converting the lacquer to the iinal hard, resistant state and causing the lacquer to become securely set on the plate.

The protective coatingV and the overlying film of lacquer may be removed, leaving the plate in the condition shown in Fig. 5. This may be accomplished by what is known as a developing operation. If preferred, however, the protective coating may be allowed `ed June 1, 1926, or in grantedJ une 1, 1926.

to remain on the and disappear w en the late is used.

On the drafwing, suitab ployed to facilitate an understanding of the invention. No undue limitations should be understood therefrom.

In place of thefui'fural-acetone resin employe in the lacquer, gne may employ other lsuitable furfural resins, or other s nthetic resins. For example, one may emp oy fur- .fural resins repared in accordance with the description given in the patent of Beebe, Murray` and Herlinger, Number 1,587 ,269, grantthe patent of Beebe, Murray andHerlinger, Number 1,587 ,273,

As another example, one may employ a phenolic condensation` resin, prepared in any suitable manner and having incorporated therein suitable sensitizing agents, or suitable accelerating a ents.

le legends are emplate and it will disintegrate i product, or phenol i Thus, one may prepare a phenolic con ensation esses in such manner as to produce a resin closely approachingv the infusible stage, may incorporate iny such :resin suitable lsensit-izing agents, or accelerators` the resins stillbeing soluble in a special solvent, and still poten,- tially reactive in some degree, may prepare a product lby any of the well known proci i lacquerffrom suoli a resin, and may apply it 95 to the sensitive areas of the plate in accordance with the invention, and may then cause the reaction to proceed to render the resin still more resist-ant and insoluble and produce a permanentv resistant coating at thev areas which are to serve as the ink-transferring portions of the plate. t

In any `case,/the resin employed in the lacquer preferably should be highly resistantto the solvent action of solvents of the order of benzene, acetone, etc., bht should still be soluble in soIne special solvent; and such special solvent, in connection with suitable thinners, should be of highly penetrating character.

Also, the lacquer should'be of such character that it can be applied as a thin, smooth layer. c

As has been indicated, it may be desired to incorporate in some of the resinous lacquers, such as a lacquer embodying a phenolic condensation product, a halogen-liberating agent, lsuch as a metallic halide, iodoform, or some ingredient which will liberate halogen under the action of light, so that the halogen will be free to act as a catalyst to expedite further hardening'of the resin. As an illustration a metallic halide, in colloidal form, may

`be introduced into a varnish, or a lacquer, by

introducing smallv percentages of drying agents, such as lead resinate,flead oxide, or other metal salts, and introducing also a small percentage of a halogen, such as iodine. The halogen will combine with the metallic salt to form a metallic halide, which remains dispersed in colloidal form throughout the varnish, In the case of aphenolic resin an easier method, and perhaps more satisfactory, is to incorporate in the resinoup lacquer about 3% of iodoform.

A light-sensitive varnish, or medium, embodying a phenolic condensation product, is disclosed, for example, in Beebe, Murray and Herlinger Patent Number 1,587,270,granted June 1, 1926. A s

Natural resins are not adapted to yield the highly resistant, insoluble printing surface desirable, and the artificial resin employed in 'the lacquer must be potentially reactive and capable of passing, in the final hardening operation, into the infusible and substantially insoluble condition.

This application constitutes a division of our application Serial No. 4103, filed January 22, 1925. y

4The foregoing detailed description has beengiven -for clearness of understanding to a metal plate an ink transfer, and appll t en ing to the plate a protective coating, Washing off theink transfer with a suitable solvent, then applying a lacquer coating comprising a synt etic resin which ishighly insoluble but, still reactive, then heating they plate to transform the lacquer coating to the final non-reactive state and cause it to become set on the exposed areas of the plate, and 'finally removing the coating at the-other areas.

MURRAY o. BEEBE. HAROLD V. HERLINGER. RAYMOND A. s WAIN.

only, and nounnecessary limitations should be 'understood therefrom, but the appended fclaims should be construed as broadly as permissible, in view of the prior art.A

What We regard as new, and desire to se-v l cure by Letters Patent, is:

1. The process of preparing a plate for the purpose set forth which comprises: applying to a metal plate an image, design, or charace ter comprising a compound of greasy or oily wcharacterhapplying to the plate a protective coating, removing from the plate the first` mentioned compound, thus leaving bare areas of the `plate exposed, applying va lacquer comprising a potentially reactive synthetic resin, andtransforming the synthetic resin to the final insoluble condition by heat.

2. The process of preparing a plate for the purpose set forth which comprises: applying to a metal plate an image, desi or character comprising a compound o greasy or oily character, applying to the plate la protective coating, removing from the plate the'l first-mentioned compound,l thus leaving bare areas of the late exposed a l in P a PPy g comprising a synthetic resln, subjecting the coatm'g formed by the lacquer to hardening treatment to'increase its insolubilityand rel sistant character, and removing the protective coating and oyerlyin lacquer.

4. The process of o rming a plate for the purpose set'forth, 4which comprises: applying

Images