FI64472B - LYUSKAENSLIGT MATERIAL FOERFARANDE FOER DESS FRAMSTAELLNING SAT FOERFARANDE FOER BEVARANDE AV EN BILD - Google Patents

Description

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3¾¾¾ C M5 \ P & exam granted 10 11 1903 'Patent meddolat ^ ^ ^ (51) Kv.lk. ^ lnt.CI.3 G 03 C 1/72 (21) Pttenttlhftkemu * - Patent «n * öknlng 762365 (22) Hakemlipilvi - Ansökntngsdag l8.O8.76 (Fl) (23) AlkupUvt - Glltighettdag 18. 08. 76 (41) Has become public - Bllvlt offentllg 19.02.77

Patent * and National Board of Registration (+4) Date of filing and issue. -

Patents and registration of anticipation Anatia utiagd och uttskriften pubiicerad 29.07.83 (32) (33) (31) Requested privilege — Begird prlorltet 18.08.75

Switzerland-Switzerland (CH) 10703/75 (71) Neste Oy, Keilaniemi, 02150 Espoo 15, Finland-Finland (Fl) (72) Alain Roman, Bossey, Jean-Pierre Sachetto, St. Julien en Genevois, France-France ( FR), Manfred Wust, Dardagny, Jean Koutroulos, Carouge / Ge, Switzerland-Schweiz (CH) (7 * 0 Forssen & Salomaa Oy (5 * 0 Photosensitive material, process for its production and method for image capture - Ljuskänsligt material, förfarande för dess framställning samt förfarande för bevarande av en bild

The invention relates to a photosensitive material and to a process for producing this material and to a method for capturing an image using the photosensitive material.

This material is characterized in that at least on one side thereof at least the surface part contains uniformly distributed diiodopropylcellulose.

A material corresponding to the above definition can be obtained by using several methods of preparation.

In one embodiment, the material comprises paper formed from a blend of papermaking fibers comprising cellulosic fibers and diiodopropylcellulose fibers. This paper can be made of, for example, 70-90% by weight of cellulose fibers and 10-30% by weight of diiodopropylcellulose fibers.

64472 According to a variant of this procedure, the diiodopropylcellulose fibers are at least partially replaced by particles of diiodopropylcellulose powder.

In another form, this material comprises paper formed solely of diiodopropylcellulose fibers.

According to another method, said material comprises a mixture of allyl cellulose fibers and diiodopropyl cellulose fibers.

Numerous other forms of material are possible, in particular the following: Paper formed from a mixture of cellulose fibers, allyl cellulose fibers and diiodopropyl cellulose fibers.

- Paper formed from a mixture of fibers of at least one synthetic material, for example polyethylene, polypropylene, etc., and diiodopropylcellulose fibers (in this variant of conversion, diiodopropylcellulose fibers can be at least partially replaced by particles of diiodopropylcellulose powder).

- Paper formed from a mixture of cellulose fibers, fibers of at least one synthetic material and diiodopropylcellulose fibers. (In the variant, at least part of the latter is replaced by particles of diiodopropylcellulose powder).

Paper formed from a mixture of fibers, allyl cellulose fibers and diiodopropyl cellulose fibers of at least one synthetic material.

Paper formed from a mixture of cellulose fibers, synthetic fibers, allyl cellulose fibers and diiodopropyl cellulose fibers.

- Diiodopropylcellulose film.

- A film formed of allylcellulose as an inner part and diiodopropyl-8-cellulose as at least one surface part.

- A film formed by at least one film-forming polymeric material, for example polymethyl methacrylate, polyvinyl alcohol, epoxy resin, polyester, phenolic resin, a cellulose polymer containing 3 64472 diiodopropylcellulose fibers in dispersion. In a variation of this embodiment, the diiodopropylcellulose fibers may be at least partially replaced with particles of diiodopropylcellulose powder.

- A surface layer covering a suitable support structure, such as a sheet of paper or cardboard, a plastic film or the like, formed of at least one synthetic or cellulose-derived high molecular weight binder, such as polyvinyl alcohol, acrylic latex, and particles.

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The process for producing a photosensitive material is characterized in that / X f is formed into a fiber mixture consisting at least in part of diiodopropylcellulose fibers, and a sheet material is produced from the fiber mixture in a manner known per se.

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According to a first embodiment, to perform the process, a> rh / sheet of paper is prepared from a homogeneous mixture of cellulosic fibers and diiodopropylcellulose fibers. For this purpose, it is possible to proceed in a manner typical of the production of conventional paper and it is possible to use machines normally used to carry out this production process.

As a modification of this first production method for carrying out the process, it is possible to replace at least some of the cellulosic fibers with fibers of at least one synthetic material, for example polyethylene, polypropylene, polyamide fibers, etc.

In this first procedure, in terms of the performance of the process and its conversion, the diiodopropylcellulose fibers can be at least partially replaced by particles of diiodopropylcellulose powder.

According to another embodiment of the process, only diiodopropyl isellulose fibers are used to make the paper sheet.

According to another embodiment of the process, the paper sheet is made from a homogeneous mixture of cellulosic fibers and / or fibers of at least one synthetic material, this material also containing allyl cellulose fibers, and at least one side of the sheet thus formed is contacted with at least a portion of iodine is converted to diiodopropylcellulose fibers as a result of the iodine addition reaction to allylcellulose.

According to another embodiment of the process, an allylcellulose film is prepared and then at least one side of this film is x contacted with an iodine solution for a time sufficient for at least a portion of this film, starting from its surface, to be diiodopropylcellulose.

With respect to the preparation of the allylcellulose film, it is possible to proceed by any suitable method, for example by a well-known technique called "solution casting", which involves pouring a solution of the film-forming material in a volatile solvent onto a smooth surface formed by, for example, a flat surface or a rotating roller.

Another procedure for performing the process comprises directly preparing a film formed of at least one film-forming polymeric material containing diiodopropylcellulose fibers or powder particles. To carry out this production method, it is possible to mix a powder of a thermoplastic polymer, for example polyethylene, polyvinyl chloride, etc., with diiodopropylcellulose fibers or powder particles to form a homogeneous dispersion, and to prepare a photosensitive film from this dispersion by a conventional extrusion process. It is also possible to take advantage of any suitable technique, in particular the "solution casting technique". In the latter case, a suspension of diiodopropylcellulose in the form of fibers or powder particles in a solution of the film-forming polymeric material is used for the production of the film.

As the film-forming polymeric material, it is possible to use, for example, an acrylic or methacrylic polymer, a vinyl polymer or also an epoxy resin, a polyester, a phenolic or epoxy-phenolic resin, etc.

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Diiodopropylcellulose fibers or powder particles can be obtained by an iodine addition reaction with allylcellulose, this reaction preferably taking place at room temperature. The degree of substitution of the allyl cellulose used for this preparation is not less than 0.05 and not more than 3. In particular, it is possible to use allyl cellulose having a degree of substitution between 0.05 and 0.65 (water-soluble product) or allyl cellulose having a degree of substitution between 0.7 and 1.5 (a product soluble in certain organic solvents such as N-methylpyrrolidone and dimentyl sulfoxide).

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To prepare iododopropylcellulose fibers, the iodine addition reaction with allylcellulose can be carried out by dispersing allylcellulose in the form of fibers in a solution of iodine in a suitable solvent such as water, organic solvent such as methanol, ethanol, carbon tetrachloride, chloroform, etc. In this way, diiodopropylcellulose is obtained in the form of fibers which are white in color.

For the preparation of diiodopropylcellulose powder, it is possible to prepare a solution of allylcellulose in a suitable solvent, then dissolve the iodine in this solution or mix this solution with the iodine solution. In this way, diiodopropylcellulose is obtained in the form of a precipitate. This can be separated from the liquid phase and dried. Thus, diiodopropyl cellulose powder is obtained which is white in color.

The use of a photosensitive material for image capture is characterized by exposing the surface of the material to electromagnetic radiation having at least a portion of its wavelengths up to 0.315 microns by modulating the intensity of this radiation in the form of the image surface.

As the electromagnetic radiation source, for example, it is possible to use a mercury vapor lamp, the emission of which is mainly formed by the ultraviolet part of the electromagnetic radiation spectrum. For example, in order to modulate the intensity of the radiation according to the contours of the image, it is possible to use a shade or filter for electromagnetic radiation, the surface of said shield or filter having portions which absorb differently wavelengths lower than 0.315 microns. In particular, it is possible to use a conventional type of photographic negative as a screen or to form an image by projecting with a suitable optical system.

The irradiation time depends on the iodine content in the surface part of the material and the desired contrast.

This time is preferably between a few tenths of a second and a few minutes.

The image appears in the form of discolorations that are yellow to brown in color, corresponding to the irradiated portions of the surface of the material. These discolorations or dots differ in color contrast from those parts of the material surface which have not been irradiated, said parts retaining their original white or light color. By using a blind or filter with areas on the surface having an average electromagnetic radiation emission between 0 and 100 96, it is possible to form an image whose intensity of discolorations or points can vary continuously between maximum intensity and barely perceptible intensity.

The formation of colored spots or spots can be combined with the radical iodine released by diiodopropylcellulose under the influence of radiation having a wavelength of less than or equal to 0.515 microns, and the recombination of these radicals in the form of molecular iodine absorbed by the cellulose fiber and yellow in color.

Cellulose macro-radicals are also formed at the same time as radical iodine.

It is possible to modify the color of the image and / or increase its contrast by causing chemical evolution by forming colored compounds between molecular iodine and at least one suitable substance.

For this purpose, for example, it is possible to treat the surface of the photosensitive material before or after exposure with a solution of amylose (starch paste) or naphthalflavone. Under these conditions, a 7: 64472 i t intense blue image is obtained by the formation of a colored complex with iodine. If necessary, it is possible; stabilize the complex thus formed with a suitable substance.

Molecular iodine, which is an oxidizing agent, can be used in a Redox system where a change in color is generated. By way of example, it is possible to use a Ferro-ferricyanide system (potassium ferrocyanide (yellow) + I ,, - potassium ferricyanide (red) + 2l).

Color can also be altered and the contrast of the image increased by performing a photochemical evolution involving color formation, during irradiation, by reaction between a radical iodine and a suitable organic compound such as an aromatic compound.

In particular, it is possible to use an aromatic amine as an organic compound which allows a stable color to be formed rapidly by reaction with radical iodine under ultraviolet radiation.

It is also well known that certain aromatic amines are at the same time photosensitive and sensitive to oxidation by forming colored species. However, in the absence of radical iodine, such a reaction is slow and from several hours to several days is required to achieve a stable color.

When performing photochemical development within the scope of the invention, the irradiation time required to achieve a contrast image is of the order of half a second to a few seconds, depending on the intensity of the activating radiation source used. Under the same conditions, the exposed amine itself assumes a much weaker coloration, giving the image insufficient contrast.

As the amine which results in the formation of color in the presence of iodine by radiation, it is possible to use, for example, a primary amine, such as one of the following amines: aniline, benzidine, o-dianisidine, aminophenol, 1,8-diaminonaphthalene, o-toluidine, o-phenylenediamine , m-phenylenediamine, p-phenylenediamine, 4,5-dimethyl-1,2-phenylenediamine, N, N-dimethyl-1,4-phenylenediamine, tetramethyldiamino-4,4-diphenylmethane.

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It is also possible to use a secondary aromatic amine, such as one of the following: diphenylamine, dibenzylamine, or even a tertiary aromatic amine, such as triphenylamine.

Thus, it is possible to use aromatic diamines or monoamines in which the amino group is carried by a side chain attached directly to the aromatic nucleus, the latter being a benzene, naphthenic or anthracene ring.

The introduction of the photochemical developer can be carried out by impregnating the photosensitive material with an aqueous solution of this substance or with an organic solution having a concentration of, for example, between 0.01 and 5% by weight.

Irradiation is preferably performed after elimination of the impregnation solvent. At the end of the irradiation, a contrasting image is obtained, the color of which varies according to the photochemical developer used.

By way of example, Table 1 shows certain primary, secondary or tertiary amines that can be used and also the corresponding colors obtained after irradiation / irradiation: TABLE 1

Amine Color UV radiation; after 'i --1 aniline light brown! benzidine brown o-dianisidine reddish brown aminophenyl light brown 1, Θ-diaminonaphthalene dark brown o-toluidine light brown i! p-Phenylenediamine violet brown and 4,5-dimethyl-1,2-phenylenediamine brown! tetramethyldiamino-4,4'-diphenylmethane blue j diphenylamine light brown j -1-1 9 64472

In the case where an aromatic amine is used as a photochemical developer, it may be appropriate to eliminate the excess amine not associated with iodine after image formation to avoid spontaneous parasitic staining of the material in the presence of air and under the influence of light. In fact, the majority of aromatic amines considered as photochemical developing agents are able to spontaneously form colored substances simply when exposed to air and light.

For this purpose, the photosensitive material can be subjected to a treatment after photochemical development to neutralize the amines by immersing the material in a bath formed by a dilute aqueous solution containing 0.05 to 3 parts by weight of mineral acid or organic acid. In this way, an amine salt is formed which goes into aqueous solution.

As the acid, it is possible to use, for example, a mineral acid such as hydrochloric acid, sulfuric acid, nitric acid or boric acid, etc., or an organic acid such as formic acid, oxalic acid, nitric acid, glycolic acid, tartaric acid, cinnamic acid, etc.

To further increase the contrast of the image in the event that said photochemical evolution is performed, it is possible to use a strong oxidizing agent such as persulfate (for example, alkali persulfate such as KgSgOg; Na 2 SgOg} (NH 2 J 2 S 2 Og, etc.) or hydrogen peroxide. this oxidizing agent may be added to the photosensitive material at the same time as the photochemical developer or oxidizing agent may be added to the acid neutralization bath referred to above, in which case the concentration of the oxidizing agent in the neutralization bath is, for example, between 0.05 and 3% by weight.

After photochemical evolution and possible neutralization of excess developer, the photosensitive material is washed with water and then dried. In this way, a very contrasting color image is obtained which is insoluble in water or organic solvents. The non-irradiated part of the material is free of all colored matter and retains its original photosensitivity. As a result, it is possible to form several images of the same color or different colors in succession on the same material.

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In the event that no chemical or photochemical evolution is carried out, the iodine stains formed at the time of irradiation can be eliminated in a suitable manner, for example by dissolving in a suitable solvent such as methanol. The corresponding image is thus made to disappear and then a new exposure of the surface of the material is possible to form a new image. Such deletion and formation of images can be repeated dozens of times without a significant reduction in the contrast of said image.

It is also possible to transfer the image to the surface of another image substrate (receiving substrate \ by contact between the surface of the image-bearing material and the receiving substrate pisxna. For example, it is possible to use a sheet of paper containing a white or colored substance (e.g. starch paste) suitable for colored matter. by reaction with iodine.

It is possible to take advantage of the electrostatic contrast resulting from the difference in electrical conductivity between the irradiated and non-irradiated parts of the material resulting from the release of iodine in the irradiated parts (resistivity of the order of 1.10 ohm.cm), while the non-irradiated parts retain their origin! their resistivity (about 2.10 ohm.cm), to cause the image to appear by the electrophotographic development process (dry or wet electrostatic development). One such a known process comprises forming a uniform electrostatic charge on the introduction of the material, then emanate from the surface of this reserve, on the opposite side contacting the substrate with a high conductivity, for example metal sheet, the substrate to a zero potential, thereby forming the surface of the material to the latent image, which is modulated by the electrostatic charge in the form of differences in density, and finally materializing the latent image with a toner powder (a flowing colored powder that adheres by electrostatic attraction to the surface of the material and is then melted to make the image permanent).

A detailed description of such an electrostatic development process can be found, for example, in R.M. Schaffert, Electrophotography, The Focal Press, London and New York (1965) ·; 11 64472 /

Example 1 A. Preparation of starting material (di.iodopropylcellulose fibers):

One part by weight of allyl cellulose fibers having a degree of substitution of 0.33 is suspended in ethanol having a volume corresponding to 10 ml / g of allyl cellulose and half a part by weight of iodine is dissolved in the suspension thus obtained.

The reaction medium thus formed is kept for 3 hours at ambient temperature (20 ° C) with sufficient stirring to keep the fibers in suspension. The fibers are then separated from the liquid, washed with ethanol to remove any unbound iodine and finally dried by heating with air at 60 ° C. All of these operations, from the time the iodine is introduced into the suspension, are performed in a chamber in which the emission spectrum of the illuminating light source does not include wavelengths less than 0.3 microns.

A white fibrous product is obtained in which the content of chemically bound iodine is 10.87% by weight.

B. Upon completion of the photosensitive material * Using a conventional machine type, a sheet of paper having a thickness of 30 microns is produced using only diiodopropylcellulose fibers obtained as described above as a starting material. This fabrication is also performed in a chamber whose emission spectrum of the illuminating light source does not contain any radiation having a wavelength of less than 0.316 microns.

This gives a white sheet of paper which is identical in appearance to normal cellulosic paper. This sheet is completely insensitive to heating, even for long periods of time, up to temperatures of up to 150 ° C, but it quickly turns yellow (within a few seconds) when exposed to sunlight. On the other hand, it retains its original white color indefinitely if it is kept away from electromagnetic radiation with a wavelength less than or equal to 0.315 microns.

64472 C. Using photosensitive material to capture an image:

A piece of photosensitive paper obtained as described above is exposed for 2 minutes to radiation emitted by a low-pressure mercury vapor lamp (Philips, type HTQ 7 »power 2000 W) placed 15 cm from the surface of the sheet, through a photographic negative supported on a cellulose acetate-based film.

Thus, the formation of an image on the surface of the photosensitive paper is effected by the contrast of yellow spots on a white background, the spots corresponding to the exposed points having the original hue or hue of the opaque negative sheet.

Example 2:

The procedure is the same as in Example 1, except that a mixture of untreated cellulose fibers and 23% by weight of diiodopropylcellulose fibers used in papermaking is used as a starting material for the production of photosensitive paper.

The color of the photosensitive paper thus obtained is white, corresponding to an optical density of 0.10 (a value identical to the density value of normal cellulosic paper).

The optical density of the exposed parts of the image varies as a function of the irradiation time, as shown in the table below: Irradiation time (minutes): Optical density: 1 0.12 5 0.13 5 0.14 7 0.15 10 0.16 64472 ί 13

Example 5:

The procedure is the same as in Example 1, except that diiodopropylcellulose fibers made from allylcellulose fibers having a degree of substitution of 0.63 instead of 0.33 are used.

These diiodopropylcellulose fibers have a chemically bound iodine content of 15 to 53% by weight.

The appearance and properties of the photosensitive paper are identical to those of the photosensitive material of Example 1 and the same result as in Example 1 is obtained when this paper is used to record an image.

Example 4:

Identical to Example 1, except that diiodopropylcellulose fibers made from allylcellulose fibers having a degree of substitution of 1.5 are used. The chemically bound iodine content of the diiodopropylcellulose fibers is 19 to 5% by weight.

A photosensitive paper having the same appearance and properties as the photosensitive material of Example 1 is also obtained.

Example 5i

The image formed on the photosensitive material of Example 2 is wiped off by immersing a piece of the material carrying this image in a methanol bath for 10 seconds. This piece or part of the photosensitive material is dried. After drying, this material appears completely free of traces of the image and has the same uniform white hue or nuance as before the formation of this image.

The recording of the image in the same manner as in Example 1C is then repeated with identical results.

Perform 5 image fade and save cycles without a significant decrease in the contrast of the viewed image.

14,644 7 2 /

Example 6: Conversion of Image Color to Contrast by Forming a Color Complex Using a color roller, a 0.5% by weight aqueous solution of starch paste is applied to a piece of photosensitive material of Example 2 bearing the image formed as described in Part C of this example.

Those parts of this image that are originally yellow in color will immediately assume a blue color.

Example 7:

The procedure is the same as in Example 6, except that the aqueous solution of starch paste is replaced by a 0.5% solution of starch paste in a mixture of equal volumes of water and ethanol.

Those parts of the image that were originally yellow in color immediately adopt a brown color with a very high stability (the image thus formed is unchanged after the material has been stored for one month).

Example 8i (Improving stability against daylight in the image obtained according to Example 6)

The procedure is the same as in Example 6, but before imaging, the photosensitive material is impregnated with an aqueous solution of potassium oxalate and then dried.

The same result is obtained as in Example 6, but greater image stability with respect to the effect of daylight. (This improvement in image stability is possibly the result of the formation of potassium iodide by the reaction between iodine and potassium oxalate at the time of irradiation of the material).

Example 9: (Formation of a colored complex in a photosensitive material before capturing an image with an imported substance)

The procedure is the same as in Example 2, except that before subjecting the photosensitive material to radiation, it is impregnated with a 1.6% by weight ethanol solution of diphenylamine 644 72 i {\ l5, after which the material is dried.

The image thus obtained consists of stains which are brown in color and which, in response to the exposed parts, contrast with the unexposed parts which retain the original nuance or tone of the photosensitive paper.

Example 10;

The procedure is the same as in Example 9, except that an impregnating solution of 1.5% by weight of 1,4-phenylenediamine in ethanol is used.

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glycol. The material is dried at 80 ° C to eliminate alcohol and thus exposed to radiation for 2 minutes. A dark purple-brown image is obtained.

The paper thus obtained with the image is immediately washed in an aqueous solution containing $ 1 formic acid and $ 0.2 ammonium persulfate ((UH 2) 2 S 2 O 4). The color of the image changes from purple to brown. The sample is then washed in water and dried. Finally, a permanent, highly contrasting image is obtained on a white background. The optical densities in the non-image and image zones are 0.20 and 0.58, respectively. No development of optical density, especially in the non-image zone, is observed over a period of more than 4 months.

It has been found that the paper thus bearing the image thus obtained has no odor, especially the odor of aromatic products. The absence of free 1,4-phenylenediamine is also confirmed. In particular, irradiation a second time in the non-image zone results in the formation of a yellow iodine image.

On the other hand, if the material is kept after irradiation without being subjected to an acid wash treatment, rapid blackening of the non-image zones (within a few hours) is observed, while the image zones show the original brownish-purple color.

Example 11?

The procedure is as in Example 10, The washing solution consists of 1% formic acid and 1% ammonium persulfate in water. The optical densities in the 16,644-72 non-image and image zones are 0.17 and 0.69, respectively. / No development of these optical densities was observed over a period of more than 4 months.

//

Example 12: / /

The procedure is as in Example 10. The sample is irradiated for 15 seconds instead of 2 minutes. The irradiated sample is treated in a bath of $ 1 glycolic acid, 3 ° hydrogen peroxides, and $ 0.5 potassium persulfate. The corresponding densities in the non-image and image zones are 0.23 and 0.44 and are stable for more than 4 months.

Example 15t

The procedure is as in Example 10. The impregnation solution for photosensitive paper is formed with 1.5 L of Δ-phenylenediamine and 0.2 $> 1,3-phenylenediamine hydrochloride in ethanol. The washing is performed in a solution of $ 1 hydrochloric acid and $ 1 sodium persulfate in water. The corresponding optical densities in the non-image and image zones are 0.20 and 0.62 and are stable for more than 4 months.

Example 14?

The procedure is as in Example 13 · The washing solution consists of 1 $ nitric acid and 1 / o ammonium persulfate in water. The optical densities are 0.18 and 0.74, respectively, and are stable for more than 4 months.

Example 15;

The procedure is described in Example 14. The washing solution consists of 1 fo hydrochloric acid and 1 ammonium persulfate in water. The optical densities of the non-image and image zones are 0.13 and 0.45, respectively, and are stable for more than 4 months.

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Example 16:

The procedure is as in Example 1, except that a mixture of 90% by weight of freshly prepared paper-cellulose fibers and 10% by weight of di-iodopropylcellulose fibers obtained from wood cellulose and having an iodine content of 17.8% by weight is used as a starting material for the production of photosensitive paper. (The samples are irradiated at a distance of 15 cm under a mercury vapor lamp emitting ultraviolet light at a linear power of 200 V / cm).

The photosensitive material is first impregnated by the procedure of Example 10 with a solution of 0.8 $ 1,4-phenylenediamine and 0.2 10,5-phenylenediamine hydrochloride in ethanol. The papers carrying the image are washed in a solution of 1.5% formic acid and 1% ammonium persulfate in water. The following results are obtained as a function of irradiation time: Irradiation time Optical density image Optical density background 5 seconds 0.54 0.16 3 "0.48 0.15 1.5" 0.32 0.14 0.8 "0.3" ° '26 ° .1 «

No development or change in optical density was observed over a period of more than 4 months.

Example 17; A. Preparation of allylcellulose film:

A 5% by weight aqueous solution of allylcellulose having a degree of substitution of 0.4 is cast on a flat smooth surface. The water is evaporated at a pressure of 20 mmHg at ambient temperature. In this way, a transparent allylcellulose film with a thickness of 40 microns is obtained.

18 64472 3l Manufacture of photosensitive material;

The allylcellulose film obtained as described above is kept immersed for 24 hours in an ethanolic solution of iodine (containing 10 g of iodine / l of ethanol), after which the film is washed with ethanol until colorless and finally dried in a dry air stream at 50 ° C.

All the steps described in Part B of this example are performed in a light-illuminated chamber free of radiation having a wavelength of less than 0.4 microns.

In this way, a diiodopropylcellulose film having a chemically bound iodine content of 13% by weight is obtained.

C. Use of photosensitive material for image art:

The procedure described in Example 1, Part C is followed.

In this way, an image is obtained consisting of yellow dots or discolorations corresponding to the exposed points, which contrast with the unexposed parts of the material which remain colorless.

The optical density of these unexposed parts is 0.22, while the density of the exposed parts varies as a function of the exposure time as shown in the following table: Irradiation time (minutes) t Optical density: 1 0.46 2 0.64 4 0.74 6 0.80

Example 18;

The procedure of Example 11 is followed, but using an allylcellulose film having a degree of substitution of 1.5 and prepared from a 5% by weight solution in N-methylpyrrolidone by evaporating the solvent at a pressure of 20 mmHg at 80 ° C.

1? : 644 7 2 /)

The content of chemically bound iodine in the diiodopropylcellulose film is 17.6% by weight.

After exposure of the material, an image of yellow discolorations is obtained with an optical density of 0.2 for unexposed portions, while the optical density of the exposed portions varies as a function of exposure time, as shown in the following table: Irradiation time (minutes): Optical density: 1 0.32 2 0, 38 4 0.36 6 0.51 10 0.60

Example 19: (Multipurpose of the photosensitive material of Example 17)

The procedure described in Example 5 is followed, but the photosensitive material of Example 17 is used. The result obtained is similar to that described in Example 5.

Example 20: (Electrophotographic development of the image formed on the photosensitive material of Example 18)

After the light-sensitive material of Example 18 is applied for 10 minutes to ultraviolet radiation under conditions which are identical to those in Part C of Example 1 described conditions, the surface of the material is subjected to a corona discharge of 600 V, which is administered evenly over the entire surface of the opposite side of the material being, in contact with the ground in the combined alumiiniarkkiin or - plate.

The result is an electrostatic latent image with an electrostatic contrast of 15 between the exposed parts and the unexposed parts. (This contrast is the result of the resistivity of the exposed parts being 1.2 · 10 ohm / cm, while the resistivity of the unexposed parts is 18 · 10 ohm / cm).

Claims (16)

1. Light sensitive material, characterized. thereof, comprising a sheet where at least one surface portion on at least one side contains evenly distributed diiodopropyl cellulose. 2. A material according to claim 1, characterized in that said sheet is a sheet of paper formed from a mixture of cellulose fibers and diodopropyl cellulose fibers. 3. A material according to claim 1, characterized in that said sheet is a sheet of paper formed from cellulose fibers and containing the odopropyl cellulose powder particles. Material according to claim 1, characterized in that said sheet is a sheet of paper formed of only diodopropyl cellulose fibers. 5. A material according to claim 1, characterized in that said sheet is a sheet of paper formed from a mixture of cellulose fibers, fibers of at least one synthetic material and diiodopropyl cellulose fibers. 6. A material according to claim 1, characterized in that said sheet is formed of a diodopropyl cellulose film. 7. A material according to claim 1, characterized in that said sheet is formed of a film of a polymeric material which forms at least one film containing diiodopropyl cellulose fibers as a dispersion. Process for producing a light-felt-wear material according to claim 1, characterized in that it forms a fiber blend which at least partially consists of diiodopropyl cellulose fibers, and produces a sheet material of the fiber blend in a manner known per se. Process for producing a photosensitive material according to claim 1, characterized in that an allyl cellulose film is prepared and then at least one side of this film is contacted with an iodine solution for a sufficient time to at least part of