US3002851A - Photosensitized transparent element - Google Patents

Description

3,002,851 PHGTGSENSITIZED TRANSPARENT ELEMENT Jack L. Sui-kin, Cleveland Heights, and Ronald C. Vickery, Novelty, Ghio, assignors to Horizons Incorporated, Princeton, Ni, a corporation of-New Jersey r No Drawing. Filed Mar. 28, 1957, Ser. No. 649,009 2 Claims. (Cl. 117-34) This invention relates to a sensitized transparent member of rigid plastic. More particularly, it relates to articles such as a card for data recording systems or an identification card, or even a slide for subsequent projection, or other articles formed of a presensitized transparent rigid thermoplastic member.

Data recording systems based on cards are becoming increasingly useful in the complex society of the present day. Business machines have been devised for retrieving the information stored and recorded on cards, either in the form of perforations or in the form of visible symbols. Recent data recording systems even involve cards which combine a perforated portion with a film secured to a window cut out of the card proper. Such cards are tedious to manufacture and are subject to failure when the film separates from the supporting card portion.

To overcome some of the disadvantages inherent in such cards, it has been proposed that transparent cards may be fabricated from synthetic thermoplastic materials and sensitized either by direct imposition on the surface of the plastic of a means which will be photosensitive as for example is shown in Patent 2,781,265, issued February 12, 1957, or by the incorporation of a photosensitive system within the base material.

In the first of these approaches it has been observed that the superimposed photosensitive material tends to curl, or otherwise cause destruction of the base material. Furthermore, the scratch resistance of the photosensitive material is particularly low. In order to reduce the sus ceptibility to destruction, it has been proposed to reinforce the base material by means of an additional supporting layer but this has been found to seriously diminish the transparency of the over-all laminated product.

The second approach, in which a photosensitive material is incorporated within the plastic system, usually requires expensive materials and careful control of the processing conditions in order to avoid undesirable side reactions.

We have now found a third method for incorporating the photosensitive material into the plastic or resinous material constituting the information card which is free from the disadvantages attendant on either of the previously practiced methods.

In accordance with our invention, a suitable synthetic plastic material, such as polyvinyl chloride, polyvinyl acetate, polystyrene, or the like, is formed into a flat card of the desired size and shape. Where the original material is not initially translucent, it is converted to a translucent blank by any suitable treatment as will later be described. Thereafter, the translucent blank is coated with a photosensitive composition such as one incorporating diazo photosensitive materials. In order to cause the photosensitive material to become firmly embedded within the plastic matrix, we have found it to be necessary to heat the composite to a temperature not exceeding about 130 C. while applying a moderate pressure to the composite. Under these conditions the photosensitive material migrates into the plastic base to a suflicient extent to obtain the desired benefits and to avoid the disadvantages found in prior art devices. The photosensitivity of the diazo material is not destroyed provided the temperature is not increased unduly and provided further that the duration of the heating step ted States Patent Patented @ct. 3, 1961 is suitably restricted. The resulting sensitized member has, by this treatment, been converted from a translucent material to a transparent material. After photoexposing, it may be developed in the usual way, for example, by 5 exposure to ammonia vapors or by the application of a wet alkaline solution of a suitable coupler. The following examples will serve to further illustrate our invention.

Example I Sheets of polyvinyl chloride were coated with Diazo N3CF (p diazo-diphenylamine formaldehyde condensate-2ZnCl The resulting coated article was heated in an oven at 120 C. while subjected to a pressure sufficient to cause flow (640 p.s.i.). At five-minute intervals sheets were withdrawn from the oven and tested for photosensitivity. It was found that even after twenty minutes at 120 C. the photosensitivity of the heat-treated sensitized plastic was not impaired to any noticeable 2O extent.

Example I] Example 111 Examples I and II were repeated using polystyrene sheets which had been rendered translucent by etching the polystyrene chemically with tetrahydrofuran in water. Other etching media, and even mechanical means such as sandblasting may be provided to render the thermoplastic translucent.

Example IV The experiment of Example I was repeated with Diazo N26 (p-diazo-N-ethyl-N-beta hydroxyethylaniline- /2ZnCl with similar results.

By means of the heat and pressure applied to the base material after the coating of diazo has been applied, the base is converted from a translucent material to a transparent material and hence meets the requirements for modern data storage cards in this respect. It will be seen, therefore, that the heating operation by means of which the sensitized material is caused to be impregnated into the plastic base, accomplishes two purposes; not only does it render the resulting blank transparent, it also serves to distribute the sensitized material Within the body of the blank and thereby avoid the tendency to curl experienced with prior art coated plastic base materials.

While We have disclosed specific diazonium compounds in connection with the described examples, it will be understood that by varying the couplers, many colors over a considerable range of the spectrum may be obtained.

The use of a roughened and translucent substrate is preferred because it contributes to the tendency of the diazo material to adhere to the base, but we wish it understood that material which is initially smooth and transparent may be processed in accordance with our invention.

Having now disclosed our invention in accordance with the patent statutes, we claim:

1. A method of forming a transparent photosensitized element of rigid vinyl plastic material selected from the group consisting of polyvinyl acetate, polyvinyl chloride and polystyrene which comprises: applying a solution of a photosensitive diazo coating to a solid transparent base References Cited in the file of this patent composed of said vinyl plastic and thereafter concurrent- 1y subjecting the coated base to a temperature between UNHED STATES PATENTS about 100 C. and 150 C., and a pressure of at least 1,966,412 Krieger July 10, 1934 500. p.s.i for a time sufiicient to permit the diazo coat- 5 2,501,874 Peterson Mall 1950 ing material to migrate into the body of the base material 2,593,9 8 Slifkin Apr. 22, 1952 but not sufiicient to destroy the photosensitivity of said 2,598,453 Slifkin May 27, 1952 diazo coating material, 2,602,740 Van Der Grinten July 8, 1952 2. The method of claim 1 wherein the pressure is be- 2,602,742 Buskes et a1. July 8, 1952 tween 500 psi. and 1000 psi. 10 2,613,149 Unkauf Oct. 7, 1952

Claims (1)

1. A METHOD OF FORMING A TRANSPARENT PHOTOSENSITIZED ELEMENT OF RIGID VINYL PLASTIC MATERIAL SELECTED FROM THE GROUP CONSISTING OF POLYVINYL ACETATE, POLYVINYL CHLORIDE AND POLYSTYRENE WHICH COMPRISES: APPLYING A SOLUTION OF A PHOTOSENSITIVE DIAZO COATING TO A SOLID TRANSPARENT BASE COMPOSED OF SAID VINYL PLASTIC AND THEREAFTER CONCURRENTLY SUBJECTING THE COATED BASE TO A TEMPERATURE BETWEEN ABOUT 100*C. AND 150*C., AND A PRESSURE OF AT LEAST 500 P.S.I., FOR A TIME SUFFICIENT TO PERMIT THE DIAZO COATING MATERIAL TO MIGRATE INTO THE BODY OF THE BASE MATERIAL BUT NOT SUFFICIENT TO DESTROY THE PHOTOSENSITIVITY OF SAID DIAZO COATING MATERIAL.