US2495661A - Reproduction material - Google Patents

Description

Jam. 4, R. J. SCANLAN 2,495,661

REPRODUCTION MATERIAL Filed July 24, 1945 8 ABSORPTIVE LAYER SUBSTRATUM 4V RAYMOND J SOANLAN 1N VEN TOR.

aiented Jan. 24, 19 50 REPRODUCTION MATERIAL Hasbrouck Heights, N. J.,

Raymond J. Scanlan,

assignor to Keufiel & Esser Company, Hoboken,

N. l, a corporation of New Jersey Application July 24, 1945, Serial No. 606,876

4 (llaims. 1

This invention relates to a new material for making line reproductions and to processes for producing such new material and for making reproductions therefrom.

It has been the practice in making engineering reproductions to make photocopies of originals (masters) which were usually, though not always, on so-called transparent bases, 1. e. paper, cloth or the like. The photosensitive sheet was placed in contact with the master or other original and exposed to light through it. It was thereafter developed according to the type of photosensitive material employed to produce a negative of the master. This negative was thereafter used to make another print in the form of a positive on cloth, paper or even metal bases.

One of the usual materials for making the negative as above identified was known as brownprint. This was generally made by coating onto a high rag content paper a solution which contained a salt or salts of silver such as silver nitrate together with salts of iron and organic acids such as the oxalates, citrates, etc., and in which the iron was in the ferric state. Upon exposure to light the iron was reduced and a reaction would take place in the presence of moisture with the silver to produce a black image in the areas which had been exposed and the unexposed areas were relatively lighter or white if the unexposed salts could be properly removed.

Regular brown-print papers and cloths had many disadvantages. One of these, varying latitude, was due in part to the fact that the coating was never uniform since the absorption of the solution by the paper varied from area to 2;

area. Prints made had an irregularity in density which aifected seriously the nature of a subsequent print made from this. Burnt areas occurred and there were under-exposed areas though the entire sheet was given the same exposure. The sensitizing solution acted on the fibers of the paper and deleteriously affected its keeping qualities. The success of the process de-' pended upon washing out the solution from the unexposed areas. This process was slow and oftentimes incomplete so that there was discoloration in areas which should be the color of the paper. These discolorations resulted in poor reproductions when prints were subsequently made. Pencil drawings were difiicult to reproduce because the irregularities of pencil lines were emphasized instead of minimized. There were other disadvantages well known to those who have used such materials.

Corresponding difiiculties and disadvantages were found when using blueprint paper. In general, these disadvantages occurred in the case of those sensitized sheets in which the coating composition contained a light sensitive material applied in solution. The types of soluble light sensitive compositions suchas blueprint and brownprint which depend upon the action of light on a photosensitive ferric salt will be referred to hereinafter as ferri-photosensitive compositions.

I have now discovered a way for obviating the difficulties above mentioned for making line reproductions and for improving the types and quality of reproductions which can be made. The invention also includes compositions whereby intensely opaque areas are produced. This results in good printing contrast with the other areas which are relatively very transparent.

According to this invention there is produced a line reproduction material comprising a base, a gelatinous layer usually made water insoluble on an impervious surface of said base impregnated with a light sensitive compound soluble in the applying medium which is usually water.

The principal objects of this invention are to provide a -ferri-photosensitive sheet which produces good uniformity of line and background color, in which the ferri-photosensitive composition is not absorbed directly in the base sheet but is limited to overlying layers, in which dimensional stability is maintained during the developing of an image by preventing the absorption in the base sheet of the water used in developing and in which curl is prevented, by providing a combination of layers on a water absorption fibrous cellulosic sheet which layers in the preferred embodiment consist of flexible synthetic resin water impermeable separation layers on both sides of the sheet, a substratum layer including gelatine and a cellulose ester in approximately equal proportions on the water proof separation layer on the top side of the sheet, a top layer of water absorbent water insoluble gelatine containing a hardener on the substratum layer impregnated with the ferri-photosensitive composition and a gelatinous water absorbing back coating on the water impermeable layer on the back side of the sheet.

The single figure of the drawing is a diagrammatic view in section showing the new reproduction material.

In carrying out this invention a suitable base 2 usually in the form of a Web is employed. Refer to the drawing. The water absorptive fibrous cellulosic sheet making up the base may be either transparent or opaque and either cloth, paper, or

the like. Preferably it is a transparent paper or cloth and the description hereinafter will generally be for such a base although this is not intended to exclude the other materials above mentioned. The base sheet is given a surface or coating on at least one side with a suitable material which will form a water impermeable separation layer 4'. betweenthe base and the later applied gelatine layer or sensitizing solution. A large number of materials may be selected for this purpose but the most desirable coating compositions are flexible synthetic resin lacquers; e.. g. those containing nitrocellulose, cellulose acetate, alkyd resin plastics, urea formaldehyde resins and other plastics or artificial resins with or without finely ground pigments. Most of these com- .positions require and contain suitable plasticizers. Such coating materials provide a thin layer on the surface of the base which is water impermeable to prevent the access of water or other liquid to the fibers of the base material.

lhis waterproofinghas many advantages as will be understood but when applied to both sides it isespecially important in connection with maintaining dimensional stability.

.One side of the coatedand waterproofed-base land the side which may hereafter be considered the'back may now be given a coating with a material the function of which is to prevent curling. A suitable composition for this back coating 6 includes gelatine and the following formula has been found successful although other corresponding compositionsfor preventing curling. may be substituted:

Gelatine grams 450 Glacial acetic acid c. c 2500 Water c. c 1500 Acetone c. c 3000 Special denatured alcohol c. c 3000 Formaldehyde (hardener) c. c 100 This coating applied .to prevent curling must have characteristics related to those of the waterproofing layer. Instead of applying a layer such as just described containing gelatine, a sec- ..ond lacquer layer may be applied which is hydrolized so that it will act in a manner similar to gelatine to absorb moisture and offset the curling which would otherwise be produced by the absorption of water in the gelatine layer on the .front of the sheet.

On the separation or waterproofing layer on the front of the base sheet is applied a layer which is known generally as a substratum 8. The purpose of this layer is to prepare the separation or waterproof layerso that a gelatine coating may be applied and will firmly adhere thereto. A suitable substratum layer contains gelatine, cellulose ester and other ingredients according to the fol- The front surface having a' substratum layer is now ready toreceive a layer of material iElwhich will itself absorb a solution containing a photosensitive material. A number of compositions are suitable for this purpose but I have found that water absorptive water insoluble hardened gelatine of the type commonly used for photographic purposes is most desirable. A composition for such a gelatine layer is:

-. Gelatine grams 555 Water gallons 3 Chrome alum c. c 60 Formaldehyde c. c 12 Finely ground pigment grams 50 This layer of gelatine is applied in the usual manher, for applyingphotographic gelatine layers but as will be noted it contains no light sensitive masuch-as brown-print coating solutions blueprint coating solutions, as .well as.. other related light sensitive. soluble materials.

In one of the preferred forms of. the-invention a brown-print:solu-tion-containinggazsalt of a polycarboxylic acidand a-polycarboxylic acid. is prepared as, for example..-one.containingthe. following ingredients:

Ferric ammoniumcitrate grams 85.0 Tartaric acid 'do 14.0 Silver nitrate do "35 .0 Water liters 0.5

Ferric ammonium oxalate grams Oxalic acid do .10 Distilled water c.-c 500 "Potassium: ierricyanide ;c. c 100 These solutions 'of light:sensitivamaterials when applied to thefront'surface ofthesheet are absorbed into orimbibed into and impregnate the gelatine layer'but are not absorbed into the fibers of'thebase; inthose cases where-the base is a normallyabsorbeht material such as paper or cloth. After application," the coated sheet isdried in the'regulanmanner, rolled and stored-or cutinto sheets. as is customary ,inmaking such types-of reproduction :materials.

This new reproduction" material: is characterized by many improved features: over those heretofore obtained with corresponding light: sensitive materials. The sheet has what is :commonly known in the'art asa short latitude. -Because of this, the reproductions have asingle tone" for a given exposure and the irregularities: of-"the master tend to be eliminated. The gelatine'layer being of uniform characteristics absorbs the coating solution uniformly as distinguished from the irregular absorption of a fibrous base. The base is protected from the chemicals of thesensitizing and developing solutions and therefore does not deteriorate for'this. reason. Again, because of the uniformity of the gelatine layer, washing (or developing) iszuniform and .complete. In making exposures'the procedureis substantially the same as .that.for"materi'als heretoforeused and'the "product can therefore be handled in equipment generally available. Since, however, washing or developing is carried out much more readily and there is no saturation of the base by water, the only drying necessary is the removal of surface moisture and, incidentally, a small amount of moisture in the gelatine layer. This is accomplished without the special dryers normally required on blueprint and other similar commercial machines by simply blowing a fan over any available source of heat such as the arc lamps of the machine onto the surface of the sheet after it has left the washing or developing tank.

1 The new material, when it is a positive print, may conveniently be corrected or changed by the draftsman through erasing lines which were drawn on the original master. This erasing may be accomplished by the application of suitable erasing fluids or by mechanical means. In either event correction or modification lines may be readily drawn in the erased areas. With the present material there are no residual ghosts produced by mechanical damage or rearrangement of the fibers in the course of erasing or by the retention of the erasing fluid which may be semi-opaque to light. This is due to the fact that the lines to be removed are not directly on the fibers but are in the superposed gelatine layer from which they can be removed without damaging or impregnating the base sheet.

The effects of fingerprints, perspiration, drops of water, etc. on the old type of reproduction materials are not found with reproduction materials produced as herein described since the efiect of such material is solely on the surface and does not reach the fibers of the base.

It has been found that unusually dense blacks may be secured in the case of brown-print solutions where the chrome alum which was the hardener in the gelatine layer, as above described, is replaced by a corresponding amount of chromic chloride.

The new reproduction materials herein described may be employed in reproduction processes to form negatives and from these negatives the same or similar new reproduction materials may be employed to make positives to be used as reproductions or to serve as originals or masters for making reproductions of various kinds.

It is customary in the art to make from the original master, a negative, 1. e. white lines on a black or other dark background, on a paper base. This negative is then employed to make a positive. Such positive may be a blue line print or a black line print but is preferably and usually a black line print on tracing cloth and this reproduction is thereafter used as a master to make blueprints or other prints in quantities as may be required for estimating or job purposes.

Having thus described my invention, I claim:

1. In a line reproduction material of the ferriphotosensitive type which produces good uniformity of line and background color, a fibrous celllulosic sheet that is water absorptive, a flexible synthetic resin water impermeable layer on said sheet which prevents the absorption in said sheet of the ferri-photosensitive composition and limits it to overlying layers, a substratum layer including gelatine and a cellulose ester in approximately equal proportions on the water impermeable layer and a top layer of uniformly water absorbent water insoluble gelatine on said substratum layer containing a hardener in the proportion of about one part hardener to 60 parts of gelatine said hardener including at least one of the compounds, selected from the group consisting of formaldehyde, chrome alum and chromic chloride, said top layer being impregnated with the water soluble ferriphotosensitive composition which includes a ferric radical, a positive alkali radical and a polycarboxylic acid radical.

2. In a lin reproduction material of the ferriphotosensitive type which produces good uniformity of line and background color, a fibrous cellulosic sheet that is Water absorptive, a flexible syntheticresin water impermeable layer on both .sides of said sheet which will prevent the absorption in said sheet of the ferri-photosensitive composition limiting it to' overlying layers and prevent the absorption in said sheet of water used in developing the reproduction material and thereby maintain dimensional stability, 2. substratum layer including gelatine and a cellulose ester in approximately equal proportions 0n the water impermeable layer on the front side of the material, a top layer of uniformly water absorbent water insoluble gelatine on said substratum layer containing a hardener in the proportion of about one part hardener to 60 parts of gelatine, said hardener including at least one of the compounds in the group consisting of formaldehyde, chrome alum and chromic chloride, said top layer being impregnated with the water soluble ferriphotosensitive composition which includes a ferric radical, a positive alkali radical and a polycarboxylic acid radical and a gelatinous water absorbing back coating on the water impermeable layer on the back side of the material to offset curling which would otherwise be caused by the absorption of water in said water absorbent water insoluble gelatine layer applied to the front of the material.

3. In a line reproduction material of the ferriphotosensitive type which produces good uniformity of line and background color, a fibrous cellulosic sheet that is water absorptive, a flexible synthetic resin water impermeable layer on said sheet which will prevent the absorption in said sheet of the ferri-photosensitive composition limiting it to overlying layers, a substratum layer including gelatine and a cellulose ester in approximately equal proportions on the water impermeable layer and a top layer of uniformly water absorbent water insoluble gelatine on said substratum containing a hardener in the proportion of about one part hardener to 60 parts of gelatine said hardener including at least one of the compounds in the group consisting of formaldehyde, chrome alum and chromic chloride said top layer being impregnated with the water soluble ferri-photosensitive composition which includes approximately 12 parts of a ferric ammonium salt of a polycarboxylic acid, approximately 2 parts of a polycarboxylic acid and approximately 5 parts of a soluble silver salt.

4. The process for making a. line reproduction material of the ferri-photosensitive type which produces good uniformity of line and background color, comprising the steps of applying a flexible synthetic resin to at least one side of a fibrous cellulosic sheet that is water absorptive to form a water impermeable layer on said sheet which will prevent the absorption in said sheet of the ferriphotosensitive composition limiting it to overlying layers, applying a composition including gelatine and a cellulose ester on the water impermeable layer to form a substratum layer, ap-

REFERENCES CITED The following references are of record in the 15 file of this patent:

UNITED STATES PATENTS Number Name Date Schroter June 29, 1897 Schwartz Apr. 25, 1922 Rowell Mar. 5, 1935 Heidenhain May 26, 1936 Nadeau et a1 May 17, 1938 Nadeau Jan. 27, 1942 Bassist Feb. 23, 1943 Poland et al Feb. 23, 1943 Toland et a1 Mar. 2, 1943 Toland et a1 Mar. 2, 1943 Bassist Apr. 13, 1943 Bassist Mar. 21, 1944 Toland et a1 Apr. 10, 1945

Claims (1)

1. 2. IN A LINE REPRODUCTION MATERIAL OF THE FERRIPHOTOSENSITIVE TYPE WHICH PRODUCES GOOD UNIFORMITY OF LINE AND BACKGROUND COLOR, A FIBROUS CELLULOSIC SHEET THAT IS WATER ABSORPTIVE, A FLEXIBLE SYNTHETIC RESIN WATER IMPERMEABLE LAYER ON BOTH SIDES OF SAID SHEET WHICH WILL PREVENT THE ABSORPTION IN SAID SHEET OF THE FERRI-PHOTOSENSITIVE COMPOSITION LIMITING IT TO OVERLYING LAYERS AND PREVENT THE ABSORPTION IN SAID SHEET OF WATER USED IN DEVELOPING THE REPRODUCTION MATERIAL AND THEREBY MAINTAIN DIMENSIONAL STABILITY, A SUBSTRATUM LAYER INCLUDING GELATINE AND A CELLULOSE ESTER IN APPROXIMATELY EQUAL PROPORTIONS ON THE WATER IMPERMEABLE LAYER ON THE FRONT SIDE OF THE MATERIAL, A TOP LAYER OF UNIFORMLY WATER ABSORBENT WATER INSLUBLE GELATINE ON SAID SUBSTRATUM LAYER CONTAINING A HARDENER IN THE PROPORTION OF ABOUT ONE PART HARDNER TO 60 PARTS OF GELATINE SAID HARDENER INCLUDING AT LEAST ONE OF THE COMPOUNDS IN THE GROUP CONSISTING OF FORMALDEHYDE, CHROME ALUM AND CHROMIC CHLORIDE, SAID TOP LAYER BEING IMPREGNATED WITH THE WATER SOLUBLE FERRIPHOTOSENSITIVE COMPOSITION WHICH INCLUDES A FERRIC RADICAL, A POSITIVE ALKALI RADICAL AND A POLYCARBOXYLIC ACID RADICAL AND A GELATINOUS WATER ABSORBING BACK COATING ON THE WATER IMPERMEABLE LAYER ON THE BACK SIDE OF THE MATERIAL TO OFFSET CURLING WHICH WOULD OTHERWISE BE CAUSED BY THE ABSORPTION OF WATER IN SAID WATER ABSORBENT WATER INSOLUBLE GELATINE LAYER APPLIED TO THE FRONT OF THE MATERIAL.

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