US3359105A - Speed-increasing agents for an nu-vinyl amine and organic halogen dye former system - Google Patents

Description

United States Patent 3,359,105 SPEED-INCREASING AGENTS FOR AN N-VINYL AMINE AND ORGANIC HALOGEN DYE FORM- ER SYSTEM Eugene Wainer, Shaker Heights, Ohio, assignor to Horizons Incorporated, a corporation of New Jersey No Drawing. Filed Mar. 10, 1965, Ser. No. 438,760

11 Claims. (Cl. 96-48) ABSTRACT OF THE DISCLOSURE Previously known photosensitive composition comprising an N-vinyl compound such as N-vinylcarbazole, a free radical generating organic halogen compound such as CBr is enhanced by the addition of sulfur and/or nitrogen compounds, such as Z-mercaptobenzothiazole and/ or tetrazoles.

This invention relates to light sensitive compositions such as those described in United States Patent 3,042,517 issued July 3, 1962. More particularly, it relates to the addition of certain classes of nitrogen and/ or sulfur containing organic compounds to photosensitive compositions based on N-vinylcarbazole and CBr In the above noted patent I have described light sensitive compositions consisting essentially of suitable N-vinyl com-pounds and suitable organic halogen compounds, which compositions when exposed photographically yielded a latent image which was rendered visible by means of either heat or infrared.

It has now been found that the photographic speed of such compositions is significantly increase-d by the addition of various sulfurand/ or nitrogen-containing heterocyclic compounds of the types hereinafter described.

To illustrate that the addition of such compounds is effective in increasing the photographic response of such compositions to radiation in the range of 3900 Angstrom units to 4500 Angstrom units, i.e. to radiation in the visible, the following composition was prepared:

Percent in benzene Polystyrene (1 cc) l0 Eicosane (1 cc.) 25 CBr, (5 cc.) 25 N-vinylcarbazole (3 cc.) 25

This formulation was coated ,to 0.003 inch wet thick- DENSITIES FOR SECOND EXPOSURES TO MONO- CHROMATOR (5.0/5.0 SLIT WIDTHS) Wavelength A. With MBT Without MBT To show that this increase in speed is not confined to 2-mercaptobenzothiazole, the compounds listed below ice were tested using the following photosensitive formulation:

10 cc. polyvinylchloride (PVC-30), 10% in tetrahydrofuran 2 grams N-vinylcarbazole 1.6 grams CBr 40 mg. of compound being tested.

The resulting formulation was coated on gm. baryta paper in the manner described in the above noted patent to 0.003 inch wet thickness.

The coatings were exposed in four different Ways as follows:

A. To a GE. sunlamp for 60 seconds through a 21 step wedge using a printing frame with a glass face. Sixty seconds exposure was used to insure a good number of steps for counting.

B. Same as A, except a photoflood lamp was used.

C. Exposures were made to a sunlamp for l, 5, 30 and 60 seconds without a negative (step wedge) or glass plate both of which will absorb ultraviolet radiation from the sunlamp and pass only visible radiation.

D. Same as C except a photoflood lamp which has some U.V. emission but very much less than sunlamps.

After exposure the samples Were heat developed for 5 seconds at C. in an oven with rapidly moving air.

The table below shows the results of these exposures in terms of maximum density realized with each exposure and where step wedges were used, the number of steps observed.

From this it will be seen that mercapto compounds selected from the group consisting of mercapto benzothiazoles, and mercaptotetrazoles are effective in significantly increasing the response of N-vinylcarbazole, car bon tetrabromide compositions upon exposure to light and subsequent heat development.

For the compositions given in Table I the amount of the mercaptobenzothiazole or mercaptotetrazole compound which yield significantly improved results may be varied between 5 and 150 milligrams of this type of addition for the specific base formula given and optimum amounts are in the range of 40 to 75 milligrams in the base composition given. In other words, the improvement begins to be noticeable at a 5 milligram addition and begins to reach a maximum in the range of 40 to 75 after which further additions yield no large improvement on the increase in speed and increase in density at equivalent exposures.

The compositions of the instant invention are not confined to those described in the foregoing example as will be apparent from the data which follows and it is to be understood that each and any one or more of the constituents utilized in the example may be replaced by equivalent or similar materials.

Thus, instead of CBr other organic halo-gen compounds may be used, such as pentabromoethane, iodoform and other compounds such a those specifically described in United States Patent 3,147,117 issued Sept. 1, 1964 and represented by the general formula RC-X wherein each X represents a chlorine, bromine or iodine atom and not all of the Xs need be the same, and R represents alkyl, aryl, aralkyl, haloalkyl, aroyl, Cl, Br, I or H.

The same holds true for the film forming binder material, the presence of which is optional since when it is absent the composition can be applied to paper or other absorbent substrates and utilized when carried on such supports. Instead of polystyrene or polvvinylchloride, utilized in the preceding examples, other homopolymers or copolymers or mixtures of film forming materials may be utilized. For reasons not entirely understood, some film forming materials appear to'intluence the photosensitivity TABLE I.RESULTS OF EXPOSURES TO U.V. AND

ING COMPOSITIONS Exposure A B C D Compound Added 60 sec. to sunlamp 60 sec. to photoflood Exposure to sunlamp Exposure to photoflood through step wedge through step wedge without step wedge or without step wedge or glass 01 print frame glass of print frame No. of Max. N0. of Max. Time, Density Time, Density steps density* steps density* secs. secs.

No Mercapto Compound (control) 8 1.0 1.10 1 .18 1 .16 5 21 5 19 30 60 30 44 60 1.52 60 .80 ltlercapto-benzothiazole 9 1. 24 14 2. 04 l 35 1 28 5 2.13 5 1.17 30 2.46 30 2.10 60 2. 42 60 2.01 Phenylmercapto tetrazole. 8 1- 14 6 0.90 1 .18 1 32 5 58 5 78 30 1.38 30 2.15 60 1. 52 60 2. 22 Methylmercapto tetrazole 10 1.26 11 1. 08 1 .17 1 .195

5 .23 5 .46 30 95 30 1. 23 60 1.95 60 1.50 Ethyl mercapto tetrazolc 8 1.12 8 1, 1 22 1 5 72 5 24 Q0 30 1. 20 60 1.85 1.39

Density is white light reflection density using a Photovolt densitometer.

of the composition to a greater extent than others as may be seen from a comparison of the examples which follow as compared with the preceding examples.

Finally, it should be noted that instead of the mercapto compounds utilized in the preceding examples many of the several classes of the sulfur-containing organic compounds described in copending United States patent applications Ser. No. 270,551 and 398,097 filed Apr. 4, 1963 and Sept. 21, 1964 and now United States Patents 3,285,- 744 and 3,342,602, respectively or mixtures containing two or more of such compounds may be utilized to enhance the response of the N-vinylcarbazole/CBn; mixture.

Suitable sulfur-containing compounds include the following sulfur-containing organic compounds:

(1) Mercapto compounds of the type R'SH wherein R is a heterocyclic nucleus of the type commonly used in cyanine dye chemistry, as outline in column 4 of US. Patent 3,100,703 issued Aug. 13, 1963;

(2) Disulfides of the type R'SS-R' wherein R has the same meaning as in 1 above;

'(3) Disulfides of the general formula wherein R" is selected from the group consisting of H, lower alkyl and aryl; and

(4) Cyclic sulfur compounds wherein the sulfur is attached to a carbon atom in a heterocyclic ring wherein the same carbon atom is attached to two non-carbon atoms, e.g. as in rhodanine or tetrazole.

In addition to the combination of essential constituents, namely the N-vinyl compound, organic halogen compound and sulfur-containing organic compound, the compositions of this invention may contain other substances added for a specific purpose. One particularly preferred group of compounds which may be included in the compositions of this invention are the triaryl compounds of Group V elements particularly the triphenyl compounds of antimony, phosphorus, arsenic and bismuth each of which has been found to be effective in the diminishing or total elimination of the fogging occurring as a result of the thermal development step.

For the purpose of amplifying the disclosure in the preceding example, a base composition was made up as follows:

Percent in benzene (1) Elvax No. 220 (1 cc.) s- 10 (2) Eicosane (1 cc.) 25 (3) Carbon tetrabromide (5 cc.) 25 (4) N-vinylcarbazole (3 cc.) 25

Elvax is a copolymer of polyethylene and polyvinylacetatc manufactured by the duPont company.

As a control this formulation was coated under a Wratten 1 series safelight at a 0.003" wet thickness on pound baryta paper and after which was allowed to dry in the dark for 30 minutes before exposure. Comparisons were made between exposure results obtained on this control and the composition with the various sulphur compounds added to this formulation as listed in Table II. In order to produce the sulphur containing composition the designated weight of the sulphur compound listed in Table II was added to the base composition just described, thoroughly stirred until dissolved, and again coated in a 3 mil wet thickness on baryta paper.

Each of these compositions was then exposed to a 500 watt photofiood reflector type lamp, placed at a distance of 12" and the exposure time in each case was 5 seconds. The exposure was made behind a mask so that a sharp demarcation between exposed and unexposed conditions could be established. Immediately after exposure of the photoflood lamp, the sample was developed with an infrared lamp fitted with a ruby glass envelope which filtered out all radiation below 6500 A. The specimen was maintained at a distance of approximately 3 to 4" from the infrared lamp and moved continuously during thermal and infrared development to prevent localized overheating. A time period of development of 1 minute exposure to the inrfared lamp was utilized in each case. Under the conditions specified background fog development less than 0.1 unit of density and generally in the range of 0.05 unit of density could be achieved easily. An infrared development much longer than this period yielded an undesirable buildup of background fog. The improve ment in net density (measured density minus base plus fog density) is listed in Table H.

TABLE II Net density at 5 sec. Weight in exposure to Addition to base composition (above) mg. of 500 watt addition photofiood at distance of 12 inches (1) No sulphur compound (control) 0.32 (2) 2-mercaptobenzoxazole 100 2.42 (3) ZIEGXCBDtO-fi nitrobenzothiazole 50 2.62 (4) 2-rnercapto-4 phenylthiazole 60 2. 73 (5) 6-amino 2-mercaptobenzothiazole. 30 3.0+ (6) 2-ruercapto-4,6,6trimethyl-1,3-thia no 100 1. 82 (7) 2-mercapto-4-phenylthiazole 40 2. 91 (8) Diphenyl disulfide 25 3. (9) Bis(3-phenyl-2-indolyl) disulfide 40 1.96 (10) Tetramethyl thiouram disulfide 25 2.91 (11) Rhodanine 20 3. 0+ (12) 2,4 thiazolidine dione 100 2.22 (13) 2-mercaptopyridine 100 2.15 (14) 2-mercaptobenzoic acid 50 1.82 (15) 2-rnercaptobenzoic acid. 25 3 0+ Z-mercaptobenzothiazole. 25

From the data presented in Table II it will be seen that the various groups of sulfur containing compounds are all effective in significantly increasing the response of N-vinylcarbazole/carbontetrabromide compositions upon exposure to light and subsequent heat development.

For the additions in Table II and with the specific base composition given improvement in net density at a specific exposure starts to make itself evident with the additions as low as 2 milligrams of the indicated additive and optimum additions are in the range of 25 to 100 milligrams. Doubling the high level amounts to 200 milligrams, for example, yields no further improvement in the speed or in the development of net density.

The earlier emergence of the effect of the organic sulphur compounds on the base composition utilized in Table II appears to be a function of the difference in the base composition itself over that used in Table I rather than the specific sulphur compounds being added.

As previously indicated it is also advantageous to add aryl Group Vb compounds to compositions of the type described for the purpose of minimizing the fogging since in normal thermal development in the absence of such triaryl compounds care must be taken to prevent the development of background fog in the thermal step, whereas in the presence of the triphenylstibine compound the composition could be drastically over-developed and complete restraining of background fog development is observed.

The following composition was shown to be particularly effective for this purpose:

(1) 10 cc. of polyvinylchloride in freshly distilled tetrahydrofuran (2) 2 grams of recrystallized N-vinylcarbazole 3) 1.6 grams of carbon tetrabromide (4) 50 milligrams of mercaptobenzothiazole 2 cc. of a 1 percent solution of triphenylstibine in benzene The above composition was prepared under a Wratten 1 series safelight and coated at a 0.003 wet thickness on a 135 gram baryta paper and allowed to dry for /2 hour. Thereafter, it is exposed through a negative for 5 seconds to a 500 watt photofiood at a distance of 12". The image portions of this composition were developed to a net density of between 2.5 and 3 in the image exposed areas after 60 seconds development to the infrared lamp described previously. Fog levels remained regularly below 0.05 unit of density under such conditions. Continuing the infrared development for a period of 5 minutes longer raises the fog level from 0.05 to about 0.07, whereas in the absence of the triphenylstibine composition continuing the infrared lamp development for 2 minutes rather than the 1 minute recommended previously raises the background fog level to 0.32 units of density and as the infrared development is continued for a period of 5 minutes the background fog level rises above a density of 1.5 making the result effectively useless under such exposure conditions for practical purposes.

Examination of optimum levels of the triphenylstibine compound for this specific composition indicates that significant and beneficial results are obtained in a range of 0.5 to 4 cc. of a 1 percent triphenylstibine with respect to fog restrainment without major reduction on photographic speed when net densities above 2.0 in the image portions are required. Concentration above 4.0 cc. of the stated triphenylstibine solution start to reduce photographic speed and the maximum levels of net density which can be achieved.

In the composition just given, involving a combination of N-vinylcarbazole, carbon tetrabromide, mercaptobenzothiazole and the minor amount of triphenylstibine, replacement of the carbon tetrabromide with 2.0 grams of pentabromethane yielded a thermally developed-out density of 2.5 after exposure to the photofiood lamp for 5 seconds at a distance of 12" with infrared development for a period of seconds. Replacement of the 1.6 grams of carbon tetrabromide in this same base formulas with 0.7 grams of iodoform yielded a net density of 2.5 after exposure to the photofiood and a 100 second infrared lamp development after a photofiood exposure of 2 sheets.

Proportions Preferably the relative proportions of N-vinyl compound to organic halogen compound should be between 5 and 0.5 part by weight of N-vinyl compound for each part by weight of organic halogen compound; the amount of organic sulfur containing compound should be between about 2.5 and 100 parts by weight for each 1000 parts by weight of organic halogen compound; and when present, the aryl Group Vb compound should be between 5 and 50 parts by weight for each 1000 parts by weight of organic halogen compound.

I claim:

1. A photosensitive composition comprising:

(a) an N-vinyl amine;

(b) a halogen containing organic compound represented by the general formula RCX wherein each X represents an atom of chlorine, bromine or iodine and R represents a member selected from the group consisting of H, Cl, Br, 1, alkyl, aralkyl, aroyl and haloalkyl; and,

(c) a sulfur containing organic compound selected from the group consisting of (l) Mercapto compounds represented by the formula R'S-H wherein R is a heterocyclic nucleus commonly used in cyanine dye chemistry;

(2) Disulfides represented by the formula RSSR wherein R has the same meaning as in 1 above; and

(3) Sulfur compounds wherein the sulfur is attached to a carbon atom in a heterocyclic ring wherein the same carbon atom is attached to two non-carbon atoms 2. A photographic film comprising a composition according to claim 1 coated on a support.

3. A composition according to claim 1 dispersed uniformly throughout a support.

4. A composition according to claim 1 wherein the relative proportion of N-vinyl compound is between 0.5 and 5 parts by weight for each part by weight of organic halogen compound and the relative proportion of organic sulfur compound is between 2.5 and 100 parts by weight for each 1000 parts by weight of organic halogen compound.

5. A composition according to claim 1 wherein the N-vinyl compound is N-vinyl carbazole.

6. A composition according to claim 5 wherein the organic halogen compound is a halogen containing hydrocarbon.

7. A composition according to claim 5 wherein the organic sulfur compound is a mercapto compound.

8. A composition according to claim 7 wherein the mercapto compound is a mercapto benzothiazole.

9. The composition of claim 1 containing in addition a triaryl compound selected from the group consisting of triphenylstibine, triphenylbismuthine, triphenylarsine and triphenylphosphine as an antifoggant.

10. A method of photographically producing a visible image which comprises preparing a film containing the composition of claim 1, photographically exposing the film to light thereby producing a latent image in said film, and developing a visible image thereof by applying thermal radiation to said latent image bearing film whereby said visible image is simultaneously developed and fixed.

8 11. The method of claim 10 wherein the thermal radiation is in the infrared.

References Cited UNITED STATES PATENTS 3,042,516 7/1962 Wainer 9690 3,042,518 7/1962 Wainer 9690 3,046,125 7/1962 Wainer 96-90 3,275,443 9/1966 Wainer 96-90 10 3,285,744 11/1966 Sprague et a1. 9690 J. TRAVIS BROWN, Primary Examiner.

NORMAN G. TORCHIN, Examiner.

C. E. DAVIS, Assistant Examiner.

Claims (1)

1. A PHOTOSENSITIVE COMPOSITION COMPRISING: (A) AN N-VINYL AMINE; (B) A HALOGEN CONTAINING ORGANIC COMPOUND REPRESENTED BY THE GENERAL FORMULA R-C-X3 WHEREIN EACH X REPRESENTS AN ATOM OF CHLORINE,BROMINE OR IODINE AND R REPRESENTS A MEMBER SELECTED FROM THE GROUP CONSISTING OF H, C1, BR, I, ALKYL, ARALKYL, AROYL AND HALOALKYL; AND, (C) A SULFUR CONTAINING ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF (1) MERCAPTO COMPOUNDS REPRESENTED BY THE FORMULA R''-S-H WHEREIN R''IS A HETEROCYCLIC NU CLEUS COMMONLY USED IN CYANINE DYE CHEMISTRY; (2) DISULFIDES REPRESENTED BY THE FORMULA R''-S-S-R'' WHEREIN R'' HAS THE SAME MEANING AS IN 1 ABOVE; AND (3) SULFUR COMPOUNDS WHEREIN THE SULFUR IS ATTACHED TO A CARBON ATOM IN A HETEROCYCLIC RING WHEREIN THE SAME CARBON ATOM IS ATTACHED TO TWO NON-CARBON ATOMS.