US2418303A - Laminated photographic material and process for producing the same - Google Patents

Description

April l, 1947. M. R. HuTcHx'soN 2,418,303

LAMINATED PHOTOGRAPHIC MATERIAL AND PRCESS FOR PRODUCING- THE SAM original Filed July 12, 1941 INVENTOR AITORNEY' Vwhich has since matured Patented pr. 1, 1947 PAIE-Ni -OFFICE LAMINATED raorocnnrmc MATERIAL ANB raocass, Foa Av,121normcmo. Y l rms SAME Miiier Reese Hutchison, New York, N, Y., assignor, by `mesne Philadelphia,` Ilja.

originar application Juiy i2, 1941,

Serial N o.

402,128, now Patent No. 2,311,547, dated Februar'y 16, 1943. Dividedand-thsiapplication0ctoy her 24, 1941, Serial No.\416,33fk 1..;

v `11i Claims.

`This invention relates to a process for immunizing hygroscopic sheet materials against dimensional variations and to the product thereof. The

application isa division of my copending application Serial No. 402,128,` led July 12, 1941, into Patent i No. 2,311,547, dated February l16, 1943.

In-the parent application, commercial processes are described, calling for the use of hygrcfscopic sheet material which isimmune to dimen- -sionalvariations resulting from changes vin 4at-l mospheric moisture.` In-general, the sheet ma'- terial referred to presents agsurface processed Jfor theapplicationfof pictorial representations, ,line work, or the like as for instance, drawing :paper `or tracing cloth on which a design can be drawn, or paperpresenting a surfacecoated `with a light sensitive uemulsion upon which a .designLphotographically can be printed. Ordinary drawing paper, tracing cloth, photographic accuracy in thedimensions of the drawingsor copies, over long periods.Y y H y According to the Apresent invention, it is proposed toimmunize such sheet materials against dimensional variations, resulting fromphanges ,in

` atmospheric moisture, by adhering them ,to back- K ingelements which, themselves.are rimmune to such` changes, Aas, forvinstance, metalcrmglass, depending, of course, on the Aservice for Whichthe sheet -materials are intended. A waterfproof thermo-plastic is used to effect a bond between ,the sheet material and the backing element and again, depending upon the service, variations vin the technique of effecting the bond, are employed, all of which fully are set forthV inthe following detailed Vdescription inconjunction with `the ayccompanyingdrawings wherein Fig. luis asectional view, greatly enlarged, depicting a portion of a sheet of drawingpape backed with sheet metal;

coating, prior to being backedwith metal;

Fig. 3`is a sectional View, greatly enlarged, of

ici. rers-s) a portion of a metal sheet which has been given i,.d,:.tlfleltrile..-plastie;` coating, prior .tot being; faced v .Figfl is a diagrammatic view illustrating the 5 manner in whichthe thermofplasticieoated paper fand metal Sheet. pf. Figs- .Zapd 3r are.adhered:-V

Fig. 5 isa sectionalview, greatly Aenlargedpand depicting ayzpoigtion of a sheetof photographic .paper thermo-plastically adhered to `a, sheet of 1n :metal: 4. l

, Fig 6 is a sectional view, greatly enlarged, and depicting apcrtiepof a. Sheetpf photographie `:paper thermofplaetally adhered te a sheetof lglyaqssharnd; ,r I. i 4j l.2 .,l' 5a..; i a ,4., .J `lcigf4 is a sectional view, greatly enlargedde petinea portion-,0i a. Sheet Ofxpaper-,feoatedlpn one. side, with .e photographie emulsion and,v on ,l the apposite side, ,with ,afihermofplastiei..

Inl-sig, Lthereis `,depicted a Sheetdf drawing paper A adhered to a sheet of metal B (template stock `@the -neiehberheed V0f: 1%.. in thiekries) byA anL intermediate thin Alayerof thermolplastic C. The drawing paper A must havecertain harfacteristicsto,A renderit suitable for theiunction iti-ias to perforrrhV Thuseirlee the maintenance i of accurate dimensonsupon theeheetis ofpriihe Y importance, theplasticized paper should be yery thin preferably not ,more than three-thousandths of an` inch1 thick,A in. order that, given 4areas on the outer surface of the sheet will not vary from thecorresponding areas on,the inner `surface ,thereof which `is adjacent the backing element. AThe paper, also, .shouldA be very, smooth, `other-- wise .the pencil point quickly will Vbe, dulled,' mak r,ing the lines of varying Vwidthgthis, despite-the n`fact that a special black pencil, of extreme hardf ness, is recommended for accurate work. It is essential that all of the pencil-drawn lines` be thin1and sharply defined, since dimensions, accu- 40 rate .to athousandthof an inch,.may. beinvolved. wToughness of `paper also` is `a. requisite, 'because erasuresmust bemade and also because, in some cases it may ,bedesired to .machinethe metal Abacking element, in accordancewith the drawing on: thel'paper .with .which it'. is surfaced. i `,Such machining .operations might involve` the use iof saws, V.1i1es,. Sanders Vand millers ,which` haveua `tendency topull the paper apart and `which might, in :the absence' of.. proper paper strength,,result `in destroying the integrity of thelines, at the point of machining., t .g i

`The 1 thermo-plastic must also have special characteristics. Itnmust be insoluble` inavvater, so as to be unaffected `by atmospheric .dampness and its melting `point ,must be` greaterathan `are the temperatures generated by sawing, filing, sanding or milling the metal backing element, when that isv done, or the paper would separate, at the point of machining, from the metal and thus destroy the integrity of the design. A ther'- mo-plastic having a softening point of about 300 F. is recommended for this purpose. Thermoplastics, having such characteristics, currently are on the market.

, Care must be exercised, in the process of adhering the paper to the backing element, to insure a surface free of surface inequalities and to insure, also, that there be an entire absence of air or gas pockets between Vthe paper and the4 metal: otherwise, the integrity of the drawingwould be destroyed, since the dimensions of the paper on and in the vicinity of the ail" or gas pockets, would vary with changes in atmospheric moisture, for the reasons previously pointed out. f! Toobtain agood product, it is preferred-to coat *one surface of the metal with thermo-plastic, as well as that surface of the paper which, in the completed stock,will be adjacent the metal, since twok thermo-plastic surfaces more intimately will form a firm bond, than can possibly be secured if only one of the two surfaces is coated. A coat- VofV thermo-plastic may be applied to the Vpaperby-looping the latter transversely Aand y drawing it over the surface of liquid thermoplastid as is done when coating paperwith pho- V4tof'rraphic emulsion. If the paper then is drawn over a roller, past a scraper located at a xed distance from the coated surface ofthe-paper,

used for adhering the drawing paper to the metal backing must, in addition, be acid and alkaliproof, in order that the bond will survive the developing process.

The procedure followed, in applying the photographic paper to the metal backing, is the -a lightsensitive emulsion V, in itself, isbelieved to be new and is one of the featuresofthe in-` stant invention (Fig. 7),.

Special care must be Y exercised in preparing the paper before it is ad- Vthesurplus plastic will be scraped o leaving a coating-fof definite thickness upon` the paper. Figs. 2 and 3 illustrate, respectively, a sheet of paper -A and a sheet of metal B, both coated with thermo-plastic C and before being joined together.

The manner in which the paper and the metal backing element, both previously covered with *thermo-plastic, are adhered together, is illus- Y trated-in Fig. 4. The necessary apparatus consists of a frame, somewhat similar to a vacuum printing frame, in that it includes a base mem- -berlD and a top flexible member E capable 0f being brought together to dene a compartment AVF,=ff-rom which aircan be exhausted. The base ,Y Dis capable o-f being heated, preferably by electricity, -in'order that `the temperature may accur'ately be controlled. lThe backing element B "isl'a'id, coated surface up, on the preheated base plate" D andthe paper,` co-ated surface down, on top' of the backing element. In other words, the Yplastic layers, onthe paper and on the back- Ving element, are Vplaced in contact, after the base plate D has been heated.

` 'When the backing element and paper are in position, the frame is closed. Heat, having previously beenl applied to bring the hot plate temperature up tothe melting point of the thermo- Y.plastic (i. e., about 300? FJ, the air` is exhausted fromthe chamber F, until a vacuum of about thirty inches of mercury is obtained. These conditions V'areheld, for a definite period of time, `Vusually'iive minutes, during which period not only is all the air and whatever gas'may be given 'offby the melted thermo-plastic, extracted from -what otherwise would be the space between the z metal and the paper, butthe paper is firmly pressed, throughout its entire area, to the surface of the metal, by the action of the vacuumactuated flexible-member E; When the thermoplastic thus has been'cured, the bondV is complete and the drawing paper, thoroughly immunized hered to a backing element which is immune to dimensional variations. Thus, the thermo-plais-` tic U should be applied before the emulsion V., Thisv sequence is desirable since light sensitive, emulsion easily is contaminated and also, since the thermo-plastic tends to stiffen the paper which is very thin-around three thousandths ofan inch-thus making it easier to apply they emulsion when the paper loopis moved intoand out of Contact with the surface of the emulsion in the applying trough. Also, since photographic emulsions are sensitive to infra-red rays, aswell as t-o visiblelight,an emulsion is used, the sensitivityof` which initially is much highery than is .eifect the sensitivity of the emulsion, it is necessary that the product be cooled as expeditiously as possible and, for this'purpos'e, .suitable refrigerating means may beemployed.. s

To be more specific,."in 'adhering the photo- V*graphic paper toits base, the heating unit previi ously must be brought to a denite temperature,

which is held for a definitev period to effect a proper cure of the thermo-plastic. lWith thatl as aconideration, a light sensitive emulsion is selected i having an initial sensitivity gaged to permit a reooA . words, it is essential that the reduction in sen- 65sitivity accurately'be controllediptherwise, Ain

exposure time required for.. proper .exposurein printing. Y

In Fig. 6, there is i'llu'strateda sheet of photographic paper, immunized-against dimensional variations by-being adhered to a backing-element of glass, rather than of metal as in the embodiused where the light, for effecting the'exposure s111116 .te @mammal changes,

audace of photographic" e'irnilsion, is* required to pass through the backing element;j The unit includes a'sheetof plate glass K and a sheetofphotographic paper L, adhered to the glass'byrgneans iofa thin llayer of thermo-plastic M; Afterwthe glassjsurface ispcoated with a thin layer of thermo-plastic, the paper `is applied to the glass,

the 'Sameimanner as. is. the photographier Dauer applied -to the ,metal backing element and which previously has beendescribed, Here; too, the paperi must bevattachedntodthe surface ofv the glass," over its enti11e `are a, since it mustV be im f The thermoplastic, ,nadcliiionto beigetreten aidamlel- Kali-proof, must also be4 transparent, t0 permit the passage of light; Thereisalso followed the same procedure of using'anemulsion of `originally` `higher sensitivity than is required4 for printingsince here, too, the sensitivityv of the emulsion suffers as a result of the heat applied during the curing of the thermo-plastic, to attach the paper to the glass. In other words, the initial sensitivity of the emulsion is such that, after it has been in the heating frame for the length of time required to cure the thermo-plastic, say about ve minutes, the sensitivity will have dropped to the desired point for printing.

In the accompanying drawings, the invention has been illustrated merely in preferred form and by Way of example, but obviously many variations and modifications may be made therein which will still be comprised within its spirit. It is to be understood, therefore, that the invention is not limited to any specific form or embodiment, except insofar as such limitations are specied in the appended claims.

Having thus described my invention, what I claim is:

1. In the preparation of material having a photo-sensitive surface and which is immune to plane dimensional variations resulting from changes in atmospheric moisture,`the process which includes coating one side of a sheet material with a photographic emulsion having a sensitivity greater than is that necessary for the service intended, adhering the sheet material to a backing element immune to plane dimensional variations resulting from changes in atmospheric moisture by means of a layer of water-proof heatsetting adhesive located between the reverse side of the sheet material and the backing elementV and which is heated to the setting point to effect a bond between the sheet material and the backing element, the initial sensitivity of the emulsion being sumcient to compensate for a reduction in sensitivity which is occasioned by the heat applied.

2. rIhe process according to claim 1, wherein the sheet material is pressed firmly against the backing element during the heating step.

3. The process according to claim 1, wherein the heating step is carried out in a substantial vacuum.

4. The process according to claim 1, wherein the total heat allowed to affect the photographic emulsion is controlled so as to avoid reducing its sensitivity beyond that suitablefor the use intended.

5. The process according to claim 1, wherein the unit is subjected to rapid cooling after the adhesive has been set in order to arrest the action of the heat upon the emulsion, thereby to insure that the reduction in sensitivity occasioned by the heat will not render the photo-sensitive surface unsuitable for the use intended.

`l'igljlts'en'sitive photographic emulsion, the heatsettingof the adhesive in bonding the sheet material to the backing element having the effect of rnfaterially'reducing the sensitivit'yof the" photographic emulsion, and the initialsensitivity of the emulsion being sufficientlyl greater than that necessary for the service intendedto compensate for kSaid reduction in sensitivity.

7. As Van article of manufacture, a laminated Y unit comprising a metal backing element and a sheet material 'adhered the'ret'by means of a water-proof heateset adhesive and'surface-'coated with an unexposed light-sensitive'photographic emulsion, the heat-setting of the adhesive in bonding the sheet material to the backing element having the effect of materially reducing the sensitivity of the photographic emulsion, and the initial sensitivity of the emulsion being suicient- 1y greater than that necessary for the service intended to compensate for said reduction in sensitivity,

8. As an article of manufacture, a laminated unit comprising a glass backing element and a .sheet material adhered thereto by means of a water-proof light-transmitting heat-set adhesive and surface-coated with an unexposed lightsensitive photographic emulsion, the heat-setting of the adhesive in bonding the sheet material to the backing element having the effect of materially reducing the sensitivity of the photographic emulsion, and the initial sensitivity of the emulsion being, sufficiently greater than that necessary for the service intended to compensate for said reduction in sensitivity.

9. As an article of manufacture, adapted to be adhered by the application of heat to a backing element for use in a photographic process for producing on a surface of the material to be fabricated an accurate replica of some particular image, a flexible sheet material coated. on one side with a water-proof heat-setting adhesive and coated on the other side with an unexposed light-sensitive photographic emulsion, the temperature and time conditions required in setting the adhesive being such as to result in a material reduction in sensitivity of the photographic emulsion, and the sensitivity of said emulsion being sumciently greater than that necessary for the service intended to compensate for said reduction in sensitivity. Y

10. An adhesive photosensitive material according to claim 9, characterized in that the heat-setting adhesive, once set, has light-transmitting qualities at least as good as those of the sheet material.

11. An adhesive photosensitive material comprising a sheet material coated on one side with an unexposed supersensitive photographic emulsion and coated on the other side with a waterproof heat-setting adhesive, the supersensitivity of said photographic emulsion being related to and determined by the temperature and time conditions required to set said adhesive.

12. An adhesive photosensitive material according to claim 11, characterized in that the heat-setting adhesive, once set, has light-transmitting qualities at least as good as those of the sheet material.

13. An adhesive photosensitive material comprising a sheet material coated on one'side with an unexposed supersensitive photographic emulsion and coated on the other side with a Waterproof heat-setting adhesive, said emulsion being subject to a material loss of sensitivity under the temperature and time conditions required to set the adhesive and having a supersensitivity great enough to compensate for said loss.

14. An adhesive photosensitive material according to claim 13, characterized in-that the heat-setting adhesive, once set, has light-transmitting qualities at least as good as those of the sheet material.

MILLER. REESE HUTCI-IISON.

REFERENCES CITED The following references are of record in the le of this patent:

Number Number UNITED STATES PATENTS Name Date Rojas May 4, 1943 Price Mar. 23, 1915 Bourges Nov. 2, 1926 Nadeau Jan. 10, 1939 Mitchell Feb. 20, 1934 Ford Sept. 12, 1939 Brennan Sept. 16, 1941 Price Jan. 9, 1917 Hovey Sept. 5, 1933 Linderman May 7, 1935 Derepas Sept. 20, 1904 Linderman May 7, 1935 FOREIGN PATENTS Country Date British May 10, 1923 British July 5, 1938

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